Soft tissue coagulation probe

IS 2 232 688 T3

DESCRIPTION

Soft tissue coagulation probe.

Background of the invention

1. Technical sector to which the invention belongs

The present invention relates generally to structures for the positioning of one or more diagnostic or therapeutic elements within the human body, and more particularly, it relates to a power control system for electrophysiology according to the preamble of claim 1.

two. Description of the above techniques

Patents EP-A-0 628 288 and WO-A-9 730 644 respectively disclose a system of the type initially mentioned.

There are many cases in which diagnostic and therapeutic elements must be inserted into the human body. One such case involves treatment for heart conditions, such as atrial fibrillation and atrial palpitations ("flutter") that lead to an unpleasant, irregular heartbeat called arrhythmia.

The normal rhythm of the sinus of the heart begins with the sinoatrial node (or "SA node") generating an electrical impulse. The impulse usually propagates evenly through the right and left atria, and the septum of the atrium toward the atrioventricular node (or "AV node"). This spread causes the atria to contract in an organized fashion to transport blood from the atria to the ventricles, and to provide timed stimulation of the ventricles. The AV node regulates the propagation delay of the atrioventricular bundle (or "HIS" bundle). This coordination of the electrical activity of the heart causes atrial systole during ventricular diastole. This, in turn, improves the mechanical function of the heart. Atrial fibrillation occurs when anatomical obstacles in the heart disrupt the normally uniform propagation of electrical impulses in the atrium. These anatomical obstacles (called "conduction blockers") can cause the electrical impulse to degenerate into several small circular waves that circulate around the obstacles. These small waves, called "reentry circuits," disrupt the normal uniform activation of the left and right atria.

Due to loss of atrioventricular synchrony, people suffering from atrial fibrillation and palpitations also suffer the consequences of altered hemodynamics and loss of cardiac efficiency. They also face a high risk of infarction and other thromboembolic complications due to loss of effective contraction and stasis of the atrium.

While there are drug treatments for atrial fibrillation and palpitations, the treatment is far from perfect. For example, certain antiarrhythmic medications, such as quinidine and procainamide, can reduce both the incidence and duration of episodes of atrial fibrillation. However, these medications frequently fail to maintain the rhythm of the breast in the patient. Cardioactive medications, such as digitalis, beta blockers, and calcium channel blockers, can also be administered to control ventricular response. However, these drugs are poorly tolerated by many people. Anticoagulant therapy also fights thromboembolic complications but does not eliminate them. Unfortunately, drug solutions often do not remedy the subjective symptoms associated with an irregular heartbeat. They also do not restore cardiac hemodynamics to normal values ​​or eliminate the risk of thromboembolism.

Many researchers believe that the only way to truly treat the three unfavorable outcomes of atrial fibrillation and palpitations is to actively disrupt all potential pathways to the atrial reentry circuits.

One surgical method of treating atrial fibrillation by disrupting the pathways for reentry circuits is the so-called "maze procedure," which relies on a predetermined shape or pattern of incisions to anatomically create a tortuous path, or labyrinth, to electrical propagation within the left and right atrium. The incisions direct electrical impulses from the SA node along the specified path through all areas of both atria, causing the uniform contraction required for normal transport function of the atrium. The incisions ultimately direct the impulse to the AV node to activate the ventricles, restoring normal atrioventricular synchrony. The incisions are also carefully placed to interrupt the conduction routes of the more common reentry circuits. The maze procedure has been found to be very effective in healing atrial fibrillation. However, the maze procedure is difficult to perform. It requires open heart surgery and is very expensive. For this reason, despite its considerable clinical success, only a few maze processes are performed per year.

More recently, labyrinth processes have been developed using catheters that can form lesions in the endocardium to effectively create a labyrinth for electrical conduction in a predetermined route. Catheters are disclosed, by way of example, in current Applicant's own US Patent No. 5,582,609. From

ES 2 232 688 T3 typically, lesions are formed by ablation of tissue with an electrode supported by the catheter. Radio frequency (“RF”) electromagnetic energy applied by the electrode heats up, and eventually causes tissue death (ie, causes “ablation”), to form a lesion. During ablation of soft tissues (ie, tissues other than blood, bone, and connective tissues) coagulation of tissues takes place and it is this coagulation that causes tissue death. Thus, references to soft tissue ablation are necessarily references to soft tissue coagulation. "Soft tissue coagulation" is the process of crossing over of proteins in tissues causing gelation of tissues. In soft tissues, it is the fluid within the membranes of tissue cells that gels killing the cells, thereby causing tissue death.

Catheters used to create lesions (the lesions of which are 3-15 cm in length) typically include a relatively long and relatively flexible body part that has an ablation electrode at its distal or distal end. The part of the catheter that remains inserted into the patient's body is typically 23 to 55 inches (58.4 to 139.7 cm) in length and others 8 to 15 inches (20.3 to 38.1 cm) can be found. ), including the handle, outside the patient's body. The proximal end of the catheter body is connected to the handle that includes directional controls. The length and flexibility of the catheter body allows the catheter to be inserted into a major vein or artery (typically the femoral artery), directed into the heart, and then manipulated such that the ablation electrode makes contact with the tissue to be sectioned or ablated. Fluoroscopic imaging is used to provide the physician with a visual indication of the location of the catheter.

The appendages of the atrium are potential primary sources of thrombus formation. The appendages of the atrium are especially important in the transport of blood because they have a pouch-like geometry with a neck potentially narrower than the pouch itself. In this case, contraction of the appendix is ​​essential to maintain an absolute average blood velocity high enough to eliminate regions of potential stasis, which can lead to thrombus formation.

In the maze process performed with open heart surgery, the typical access points to the interior of the atria are the appendages of the atrium. Therefore, upon completion of the surgical process, the area occupied by the appendages of the atrium is removed by surgical removal of said appendages. This mitigates subsequent problems resulting from blood stasis in the appendages of the atrium, and also, from electrical isolation of the appendages from the rest of the atria. However, as noted above, open heart surgery is very expensive and the incision-based maze process is difficult to perform. While catheter-based processes are not appropriate for appendage removal, catheter-based procedures and devices have recently been developed that reposition the atrial appendages, fix them in an altered position, and / or fuse the appendage walls together. to isolate the appendages, reduce the areas of stasis and finally, the formation of thrombi. Said procedures and apparatus are disclosed in US Patent No. 5,865,791, owned by the applicant. One of these procedures involves the use of a catheter that has a loop that is tightened around the appendix. RF energy is then transmitted to the appendage via the loop to thermally fuse the appendage walls to each other, thereby isolating the appendage.

Treatment of atrial fibrillation and palpitations is believed to require the formation of long, thin lesions of varying lengths and curvilinear shapes in cardiac tissues. These long, curvilinear lesion shapes require deployment within the heart of flexible ablation elements and have multiple ablation zones. Formation of these lesions by ablation can provide the same therapeutic advantages as the complex incision patterns provided by present maze surgical procedures, but without invasive, open heart surgery.

With larger and / or longer multiple electrode elements there is a demand for more precise control of the ablation process. The supply of ablation energy must be controlled to avoid incidences of tissue damage and clot formation. The supply of ablation energy must also be carefully controlled to ensure the formation of uniform and continuous lesions, without hot spots or gaps in the ablated tissues.

The task is more difficult because the cardiac chambers vary in size from one individual to another. They also vary according to the condition of the patient. A common effect of heart disease is enlargement of the heart chambers. For example, in a heart experiencing atrial fibrillation, the dimension of the atrium can be up to three times that of a normal atrium.

Catheter-based ablation and isolation of the atrium appendages have been shown to be a significant advance over conventional open-heart surgical approaches. However, the present inventors have determined that still other improvements can be achieved.

For example, and with respect to ablation processes in particular, the inventors have determined that it can be very difficult to accurately position an ablation electrode on the surface of the endocardium by manipulating the distal end of a relatively long catheter body from a remote or remote handle. This is especially true with regard to locations in the left atrium. The present inventors have also determined that fluoroscopy is a somewhat inaccurate method for visualizing ablation electrodes during positioning and in determining whether the electrodes are in proper contact with tissues.

IS 2 232 688 T3

Additionally, a primary goal of any ablation process is to create contiguous lesions (often long curvilinear lesions) without overheating the tissues or causing burns or clots. Tissue ablation takes place at 50 ° C, while overheating takes place at 100 ° C. The current inventors have further determined that it can be difficult to produce tissue contact that meets this result with an electrode mounted on the distal end of a relatively long catheter. This is especially true in procedures where an electrode at the distal end of the catheter is pulled along the tissues. This pulling or dragging also makes exact placement of the electrode very difficult. Other drawbacks identified by the present inventors relate to the effects of convective cooling of the blood on the electrodes. For example, the power requirements of the system must be high enough to compensate for the loss of life to convective cooling.

One approach proposed for the overheating problems associated with conventional ablation catheters is the so-called "cold tip" approach. In this case, the surface of the tissues is cooled with a saline solution. While saline is useful to some extent in keeping the surface temperature below the superheat temperature, the surface temperature of tissues can still rise well above 100 ° C. These temperatures will cause the gases to expand within the subsurface tissues. Ultimately, the tissues will rupture or swell, resulting in perforations of the epicardial surface and / or dislodging of tissue extracts that can cause infarction.

Referring again to the isolation of the atrium appendages, the current inventors have determined that catheter-based processes have many of the same drawbacks as discussed, such as those relating to positioning and visualization. Additionally, the inventors have also determined that the loop can bunch the tissues when the loop is tightened and that the fusion of the tissues is improved if this bunching can be avoided.

With respect to power control, conventional ablation devices include controls that are located either on the RF energy source, or on a foot pedal. The inventors have therefore determined that such arrangements are not desirable and can make it difficult to control power during a surgical procedure.

Referring again to surgical procedures in general, a problem associated with many surgical procedures is excessive bleeding. For example, a high level of bleeding is frequently associated with the removal of lobules from the liver and certain cancerous tumors. The inventors have determined that the present surgical methods can be improved on the blood loss aspect.

Summary of the invention

The aim of the present invention is to provide a power control system for electrophysiology of the type initially mentioned, which avoids the aforementioned problems and which simplifies the creation of models of complex lesions in soft tissues, such as myocardial tissues in the heart.

To achieve the above and other objectives, a power control system for electrophysiology according to the present invention comprises the features of claim 1.

The remote control power device, which is connected to the power unit, may be located in close proximity to the patient or otherwise within the sterile area of ​​an operating room. Such an arrangement provides more convenient power control than conventional devices.

Additionally, since the power control interface is located on the remote control device, the remote control part of the entire electrophysiological system can be more conveniently brought into the sterile area because both the surgical probe and the device remote control are easily sterilizable. Conventional power control interfaces, on the other hand, are part of a remote control unit that is not easily sterilizable.

The above described and many other corresponding features and advantages of the present invention will become more clearly apparent upon understanding of the present invention with reference to the following detailed description, in consideration of the accompanying drawings.

Brief description of the drawings

A detailed description of preferred embodiments of the invention will now be made with reference to the accompanying drawings, in which Figures 10e to 10g do not form part of the invention.

Figure 1 is a side, partial sectional view of a surgical device for positioning a surgical element within the body of a patient in accordance with one embodiment.

Figure 2 is an end view of a surgical device of Figure 1.

IS 2 232 688 T3

Figure 3a is a side view of a surgical device for positioning an operative element within the patient's body according to another embodiment.

Figure 3b is a partial side view of a portion of the surgical device shown in Figure 3a.

Figure 4 is a side view, in partial section, of a part of the surgical device shown in Figure 3a.

Figure 5 is a side view of a surgical device for positioning a surgical element within the body of a patient in accordance with another embodiment.

Figure 6a is a partial sectional side view of a surgical device for positioning a surgical element within the body of a patient in accordance with another embodiment.

Figure 6b is a sectional view taken along line 6b-6b in Figure 6a.

Fig. 7 is a sectional view showing an operating element covered with regenerated cellulose.

Fig. 8a is a sectional view showing a partially hidden operating element.

Fig. 8b is a sectional view showing an alternative configuration of an operating element.

Figures 9a-9c are front views of a tongue assembly according to one embodiment.

Figure 9d is a side view of the tab assembly shown in Figures 9a-9c.

Figure 9e is a sectional view taken along line 9e-9e in Figure 9a.

Figure 9f is a front and partial sectional view of a surgical device for positioning a surgical element within the body of a patient in accordance with another embodiment.

Figure 10a is a side view of a surgical device for positioning a surgical element within the body of a patient in accordance with one embodiment.

Figure 10b is a side view, in partial section, of an alternative tip that can be used in conjunction with the device shown in Figure 10a.

Figure 10c is a side view, in partial section, of another alternative tip that can be used in conjunction with the device shown in Figure 10a.

Figure 10d is a perspective view of a probe handle according to one embodiment.

Figure 10e is a perspective view of a probe handle according to another embodiment.

Figure 10f is an exploded perspective view of a probe according to one embodiment. Figure 10g is an enlarged view of the probe shown in Figure 10f.

Figure 10h is a plan view of an electrophysiological system in accordance with one embodiment of the present invention.

Figure 10i is an enlarged view of the remote power control unit shown in Figure 10h.

Figure 11a is a sectional view of the distal area of ​​the device shown in Figure 10a taken along line 11a-11a in Figure 10a.

Figure 11b is a sectional view of an alternative distal region of the device shown in Figure 10a.

Figure 11c is a side view, in partial section, of another alternative distal region of the device shown in Figure 10a.

Figure 12 is a sectional view taken along line 12-12 in Figure 10a.

Figure 13 is a side view of a surgical device for positioning a surgical element within the body of a patient in accordance with another embodiment.

Figure 14 is a side view of a surgical device for positioning a surgical element within the body of a patient in accordance with another embodiment.

IS 2 232 688 T3

Figure 15 is a perspective view of a part of the device shown in Figure 14.

Figure 16 is a side view of a surgical device for positioning a surgical element within the body of a patient in accordance with another embodiment.

Figure 17 is a side view of a flange according to one embodiment.

Figure 18 is a sectional view taken along line 18-18 in Figure 17.

Figure 19 is a plan view of the flange illustrated in Figure 17.

Figure 20 is a side view of a surgical device for positioning an operative element within the body of a patient and applying a clamping force to a body structure in accordance with one embodiment.

Figure 21 is a side view of a surgical device for positioning an operative element within the body of a patient and applying a clamping force to a body structure in accordance with another embodiment.

Figure 22 is a side view of a surgical device for positioning an operative element within the body of a patient and applying a clamping force to a body structure in accordance with another embodiment.

Figure 23 is a plan view of a support member of the operating element of a surgical device shown in Figure 22.

Figure 24a is a plan view of another support element of the operating element.

Figure 24b is a plan view of another support member of the operating member.

Figure 25 is a side view of a surgical device for positioning an operative element within the body of a patient and applying a clamping force to a body structure in accordance with another embodiment.

Figure 26 is a side view, in partial section, of an exemplary procedure that includes the surgical device shown in Figure 20.

Figure 27 is a side view, in partial section, of an exemplary procedure that includes the surgical device having an alternative support member configuration.

Figures 28 and 29 are schematic views of a system for controlling the application of ablation energy for a series of electrodes, using multiple temperature sensing inputs.

Figure 30 is a schematic flow chart showing one implementation of the temperature feedback controller shown in Figures 28 and 29, using individual amplitude control with collective duty cycle control.

Figure 31 is a schematic view of a neural network prediction device, which receives as inputs the temperatures detected by the multiple detector elements to a given electrode region and outputs at a predetermined temperature from the hottest tissue region.

Figure 32 is a partial side view showing the use of a support catheter in conjunction with a loop catheter to hold the walls of the inverted appendage together.

Figure 33 is a partial view of the combination shown in Figure 32, illustrating additional steps of holding an appendage in an inverted orientation.

Figure 34 is a perspective view of the pressure application probe according to one embodiment attached to a support probe of the operating element.

Figure 35 is an enlarged perspective view of the pressure application probe shown in Figure 34.

Figure 36 is a partial perspective view of the pressure application probe according to another embodiment. Fig. 37 is a perspective view of a coupling device according to one embodiment.

Figure 38 is a perspective view showing a pressure application probe and aco6 device.

The procedure shown in Figure 37 used in combination with the surgical device shown in Figure 10a.

Figure 39 is a perspective view showing the coupling device shown in Figure 37 used in combination with the surgical device shown in Figure 10a.

Figure 40 is a perspective view of a coupling device according to another embodiment.

Detailed description of the preferred embodiments

Next, a detailed description of the best currently known ways of carrying out the invention will be made. This description should not be taken in a limiting sense, but merely for the purpose of illustrating the general principles of the invention.

The description is distributed as follows:

I. Probe type apparatus

II. Operating elements

III. Epicardial applications of a probe type apparatus

IV. Endocardial Applications of a Probe Type Apparatus

V. Other surgical applications

SAW. Apparatus that applies a clamping force

VII. Appliance applications that apply a clamping force

VIII. Force control

The section titles and general layout in this detailed description are for convenience and are not intended to limit the present invention.

The present disclosure discloses a number of electrode structures, primarily in the context of cardiac ablation, because the structures are suitable for use with myocardial tissues. However, it should be noted that the structures are applicable for use in therapies involving other types of soft tissues. For example, various aspects of the electrode structures have applications in procedures relating to other regions of the body, such as the prostate, liver, brain, gallbladder, uterus, and other solid organs.

I. Probe type apparatus

As shown by way of example in Figures 1 and 2, a surgical device (or "probe") (250) for positioning an operating element (252) within the patient's body comprises a relatively short stem (254 ) and a bending or flexing tab assembly (256), associated with the distal end of the stem, to support the operative element. In this case, the operating element (252) takes the form of a series of electrode elements (294), as will be indicated in more detail in the following section II. Preferably, the relatively short shaft may be about 4 to 18 inches (10.2 to 45.7 cm) in length, and is preferably 8 inches (20.3 cm) in length, while the outer diameter of the shaft is comprised preferably between 2 and 8 mm (6 and 24 "French"). The tab assembly (256) has a default usage configuration. In the exemplary embodiment shown in Figures 1 and 2, the tab assembly includes a pair of tab legs (258) and (260) and an annular member (262) that supports the operating member (252). The surgical device also includes a tubular member (264) (a cylindrical-shaped sleeve in the exemplary embodiment shown) that covers a portion of the stem (254) and is also slidable with respect thereto. The tab assembly (256) is adapted to collapse (insert configuration) in response to movement of the substantially tubular member (264) in the distal direction, and expand to the predetermined configuration of use when the substantially tubular member is displaced in the proximal direction. . A handle (266) may be provided at the proximal end of the stem (254). The tubular member (264) preferably includes a raised gripping surface (268).

Another exemplary surgical device (or "probe") for positioning a surgical element within the patient's body, generally represented by reference numeral 270, is shown in Figures 3a-4. In this case, the surgical device includes a substantially triangular shaped tab assembly (272) consisting of first and second side legs (274) and (276) and a distal leg (278). The distal leg (278), which is preferably nonlinear end-to-end and is approximately 10 to 12 cm in length, includes first and second linear portions (280) and (282) and a curved portion (284) positioned across half the distance between the ends. This tab configuration provides a spring force against the body surface

ES 2 232 688 T3 that has been selected during use (such as the wall of the atrium in a cardiac process) and the curvature in the distal leg (278) optimizes the contact between the operating element (252) and the selected surface. The tab assembly (272) collapses in the manner shown in Figure 4 when the tubular member (264) is placed thereon and will return to the orientation shown in Figure 3a when the tubular member is removed. Surgical device (270) also includes a second handle (267).

During use of the exemplary surgical device shown in Figures 1-4, the handle 266 (Figure 1) or 267 (Figure 3a) is grasped by the physician and a force is applied through the stem ( 254) and lateral legs (258) and (260) (figure 1) or (274) and (276) (figure 3a) to the annular element (262) (figure 1) that supports the operating element, or to the distal leg (278) (Figure 3a). Therefore, the stem and the side legs (including the area in which the side legs are located) must be strong enough to prevent collapse or crushing when a force is applied. The fact that the present devices do not pass through a tortuous vascular pathway to the site of interest allows the stem and barb legs to be stiffer than a conventional catheter stem. That aspect of the invention is explained in more detail below. Alternatively, the stem (254) and the side legs (274) and (276) in the embodiment shown in Figures 3a and 4 can be configured such that they flatten and form a semicircle with the distal leg (278). when a force is applied to the stem (see figure 3b). In this case, the operative element must be appropriately concealed, in one of the ways described below, to limit contact of the operative element with the desired body structure.

As shown by way of example in FIG. 5, a guidewire (286) can be used to direct and / or anchor the distal leg (278) of the tab assembly (272) shown by way of example in a anatomical anchoring site (such as the pulmonary veins shown in figure 5). Guidewire (286) passes through a lumen of stem (254). The distal end of the guide wire (286) passes through the lumen (288) formed in one of the side legs (274) and (276) of the barb assembly, while the proximal end is attached to the handle (290) . Alternatively, two guide wires (each passing through one of the side legs) can be used to anchor the barb assembly (272) at two anatomical anchor locations. Both wires would extend into the same handle.

The exemplary embodiments shown in Figures 1-5 can be arranged without the tubular member (264). These devices are especially useful in surgical procedures associated with a thoracotomy or a median stereotomy, where the tab assemblies can be easily crushed and advanced to the desired location, or they can be advanced to the desired location without being crushed. In this case, the tab assemblies can be malleable, if desired, as opposed to simply being flexible or bendable.

Referring again to Figures 6a and 6b, an endoscope (292) can pass through a lumen of a tubular element (264 ') having a pair of lumens. Alternatively, stem (254) and endoscope (292) may pass through a common lumen.

The barb assemblies shown in Figures 1-5 are preferably made from an inert, elastic wire, such as nickel titanium wire (commercially designated Nitinol material) or 17-7 stainless steel. However, an inert and elastic injection molded plastic material can also be used. The molded plastic or wire is covered by a suitable biocompatible elastomer or thermoplastic material, such as PEBAX^® or Pellethane^®. Preferably, the different parts of the tongue assemblies comprise thin, rectilinear strips of a flexible material or of a plastic material. Also, other cross-sectional and longitudinal configurations can be used. For example, the legs of the tab may taper in cross-section in the distal direction, varying, for example, the thickness or the width or diameter (if round), to provide variable stiffness according to its length. Also, variable stiffness can be achieved by changes in the composition of the material or by different techniques and processes of the material. Referring more specifically to the embodiments shown in Figures 3a-5, the distal leg (278) can be configured such that the leg is flat at the distal end, but becomes more semi-circular in cross section as said leg is brought into position. greater proximity in order to produce the stiffness profile and prevent lateral movement of the tongue assembly. The curvature of the tab legs can also be varied, and the lateral ends of the distal leg can be trimmed to provide greater lateral stability.

As shown by way of example in Figures 9a-9e, the probe barb assembly shown in Figures 3a and 4 may be replaced by a curved barb assembly (300). In this case, the barb assembly comprises an inert flat wire (302) (preferably made of Nitinol) that acts as a spring, and an external part (304) (preferably made of PEBAX^® or Pellethane^®). In its cross section, the flat wire (302) has a long side and a short side. The short sides are arranged in planes parallel to the plane shown in Figure 9d. As such, the tab assembly 300 will flex in the manner shown in Figures 9b and 9c, when the "in plane" forces F are applied to the tab assembly. Rather, the assembly will resist curvature when forces are applied "out of plane" in the manner shown in Figure 9d. Thus, it will be used to form an arcuate lesion during, for example, a process in which a lesion forms around a pulmonary vein.

It should be noted in this case that the wire (302) does not have to be rectangular or in cross section as shown. Other cross sections in which the length is greater than the width can also be used. The wire (302) can also be made from a malleable material, such as partial stainless steel or

ES 2 232 688 T3 fully annealed, instead of the spring material discussed above. The malleable embodiments will allow the operator to adjust the shape of the ablation element support structure to irregular anatomical structures.

As shown in FIG. 9f, the exemplary barb assembly 300 'includes first and second steering wires 301a and 301b that are attached to the flat spring wire 302, for example, by welding, mechanical stapling or adhesive bonding. The proximal ends of the steering wires (301a) and (301b) are operatively connected to the button (303) on a handle (266 ') via an eaves (not shown). The handle 266 'is substantially similar to the handle 266 shown in Figure 1, except for the button 303, the eave, and the arrangement for the steering wires 301a and 301b. Rotation of button (303) will cause the tab assembly to move from side to side, for example, in the manner shown in Figure 9c. Thus, in addition to simply moving the handle, the physician will be able to move the operating element (252) within the patient's body by turning the knob (303). This movement is useful when the physician attempts to precisely position the operative element within the patient's body and / or attempts to control the contact force between the operative element and the tissue surface. This is especially true when the handle and / or stem (254) cannot be displaced, due to anatomical or surgical limitations.

In the exemplary embodiment, the steering wires 301a and 301b are attached approximately at the midpoint of the flat wire loop. Other configurations are also possible, depending on the configuration of the loop that is desired after turning the knob (303). For example, one wire can be fixed closer to the top of the loop than the other. The shape of the eaves can also be varied. More detailed explanations of the realization of the steering wire, albeit with conventional catheter devices, can be found in the US patents of the same current applicant N^you 5,195,968, 5,257,451 and 5,582,609.

The stem (254) is preferably relatively rigid. As used in this description, the terms "relatively rigid" mean that the stem (or other structural element) is either rigid, or malleable, or somewhat flexible. A rigid stem cannot bend. A malleable stem is a stem that can be easily bent by the physician, assuming the desired shape without regaining the shape when released, so that it remains the same shape during the surgical process. Therefore, the stiffness of a malleable stem must be low enough to allow the stem to be bent, but high enough to resist bending when the forces associated with a surgical procedure are applied to the stem. A somewhat flexible stem will bend and spring back when released. However, the force received to bend the stem must be substantial. Rigid and somewhat flexible stems are preferably formed from stainless steel, while malleable stems are formed from annealed stainless steel.

One method of quantifying the flexibility of a stem is to observe the flexing or deformation of the stem when one end is cantilevered and a force is exerted perpendicular to the longitudinal axis of the stem at a location between the ends. This bending (σ) is expressed as follows σ = WX² (3L-X) / 6EI in which:

W is the force applied perpendicularly to the longitudinal base of the stem,

L is the length of the stem,

X is the distance between the fixed end of the rod and the applied force,

E is the modulus of elasticity, and I is the rod moment of inertia.

When the force is applied to the free end of the stem, the deflection can be expressed as:

σ = WL³/ 3EI assuming that W and L are equal when comparing different stems, the respective values ​​of E and I will determine how much the stems will bend. In other words, the stiffness of a stem is a function of the product of E by I. This product is referred to in this description as "bending modulus." E is a characteristic of the material that forms the shaft or stem, while I is a function of stem geometry, wall thickness, etc. Therefore, a stem formed from a relatively soft material can have the same bending modulus as a stem formed from a relatively hard material, if the moment of inertia of the softer stem is sufficiently greater than that of the softer stem. Lasted.

For example, a 2-inch (5.1 cm) relatively rigid stem (malleable or somewhat flexible) will have modulus

ES 2 232 688 T3 with a minimum bending of approximately 28 N-cm²(1 lb-in.²). Preferably, a relatively stiff 5.1 cm (2 in.) Stem will have a bend modulus of approximately 86 N-cm.²(3 lb-in.²) and approximately 1435 N-cm²(50 lb-in.²). By comparison, a 5.1 cm (2 inch) piece of a conventional catheter stem, which must be flexible enough to travel through the veins, typically has a bend modulus of about 2.8 N- cm²(0.1 lb-in.²) and approximately 8.6 N-cm²(0.3 lb.-in.²). It should be noted that the bending modulus ranges that have been explained are primarily associated with initial bending. In other words, the ranges of the bend modulus are based on the magnitude of the force applied at the free end of the longitudinal axis of the cantilevered stem and perpendicular to it, which is required to produce a flex of 2.5 cm ( 1 inch) from a resting position (i.e. no flex).

As indicated above, the bending of a shaft depends on the composition of the shaft, as well as the moment of inertia. The shaft can be made of an elastic material, a plastic material, an elastoplastic material, or a combination thereof. By designing the stem 254 relatively rigid (and preferably malleable), the surgical tool is better suited for the limitations encountered during the surgical procedure. The force required to bend a relatively rigid stem with the length of 5.1 cm (2 inches) should be in the range of approximately 6.7 N (1.5 lbs.) To approximately 53.4 N (12 lbs.) . For comparison, the force required to bend a 5.1 cm (2-inch) piece of a conventional catheter stem should be between approximately 0.9 N (0.2 lb.) and 1.1 N (0, 25 lb.). Also in this case, the force values ​​refer to the magnitude of the force, applied at the free end of the longitudinal axis of the cantilevered stem and perpendicular to it that is required to produce a flexion of 2.5 cm (1 in. ) from a resting position (no flexion).

Ductile materials are preferable in many applications because such materials can be plastically deformed prior to failure. Materials are classified as ductile or brittle, based on the percentage of elongation when failure occurs. A material with more than 5% elongation before failure is generally considered ductile, while a material with less than 5% elongation before failure is generally considered brittle. The ductility of the material can be based on a comparison of the cross-sectional area at break to the original cross-sectional area. This characteristic does not depend on the elastic characteristics of the material.

Alternatively, the shaft can be a mechanical component similar to a shielded conduit (sheath with a metal spiral) or Loc-Line^® flexible, which is a linear set of interlocking ball and housing links that may have a central lumen or chamber. These would be hinged as segmented sections joined linearly to form the shaft.

The exemplary tubular member 264 shown in Figures 1-6b is preferably in the form of a relatively thin cylindrical sheath (eg, approximately 1.2 mm (0.005 inches) thick) and has a outer diameter preferably less than 46 mm (0.180 inches). The sleeve material is preferably lubricating, to reduce friction during movement of the sleeve with respect to axis (254) and tab assemblies (256) and (272). For example, materials made from polytetrafluoroethylene (PTFE) can be used for the sheath. The distal end of the sheath must be relatively flexible to prevent damage. If necessary, additional stiffness can be achieved in the remaining part of the casing by coating the casing with a braided material covering with a PEBAX material.^®(comprising a polyethel block amide, related to nylon). Other composites made from braided PTFE with a more rigid outer layer and other lubricating materials can also be used.

Alternatively, the tubular member (264) can be substantially rigid, being formed of the materials described above with respect to the stem or shaft (254).

As shown by way of example in Figure 10a, a surgical probe (308) in accordance with another embodiment of this invention comprises a relatively rigid stem (310), a handle (312), and a distal section (314). The stem (310) consists of a hypodermic tube (316), which is rigid or relatively rigid, and an outer polymer tube (318) on said hypodermic tube. A relatively rigid malleable or somewhat flexible tube will preferably have a modulus of curvature between approximately 86 N-cm² (3 lb-in.²) and approximately 1435 N-cm²(50 lb-in.²). The handle (312) is similar to the handle (266) explained above, in that it comprises a PC panel (320) to connect the operating elements in the distal part of the probe to a power source. The handle (312) preferably consists of two molded half handles and is also provided with a reinforcing element (322). An operating element (254) (in this case, in the form of a series of electrode elements (294)) is disposed in the distal or remote section (314). This embodiment is particularly useful because it can be easily inserted into the patient's body through an insertion opening, such as a trocar.

A handle (312) shown in Figure 10a is intended for use in a conventional power supply configuration in which the transmission of power from an RF generator (or other power source) to the electrode (294) is controlled by a stripping switch. As shown by way of example in FIG. 10d, and in accordance with one embodiment of the present invention, a handle (312 ') is provided with a manually operable start-stop switch (313). The start-stop switch (313) allows the clinician to selectively turn on and off the supply of RF ablation energy (and other types of power) to the electrode (s) located at the distal portion of the probe.

IS 2 232 688 T3

In addition to the global start-stop switch (313), the handle (312 ") shown in FIG. 10e by way of example also comprises a series of individual start-stop switches (315) for each of the electrodes. Individual start-stop switches (315) allow the clinician to selectively control the supply of power to individual electrodes. The exemplary handle (312 "), having seven individual on-off switches (315), is preferably used on a probe having seven electrodes. In case, for example, the doctor tries to ablate tissues with only three of the electrodes, then the chosen electrodes can be activated by means of the corresponding switches (315) before placing the global on-off switch (313) in the position "March".

A series of indicator elements (317) are also disposed on the exemplary handle (312 ") shown in Figure 10e. Preferably, there is an indicator element (317) for each of the start-stop switches (315). In the embodiment shown, the indicator elements (317) take the forms of buttons that remain raised when a corresponding start-stop switch (315) is pressed. This provides the physician with a tactile and visual indication of the on-off status of the switches (315). Indicator elements 317 may also take the form of indicator lights. They can also be used to indicate the start-stop situation of the switches (315), audible indicators. For example, a loudspeaker on the handle or the power supply device can be used to periodically indicate which of the switches 315 is in the "on" position.

In accordance with another aspect, a probe can be configured such that the handle is reusable, and the remaining parts of the handle are separately removable or reusable. Referring again to Figures 10f and 10g, the exemplary handle (312 ") comprises an edge-type connector having a first portion (319) on the handle and a second portion (321) on the remaining portion of the handle. probe. In the embodiment shown, the remaining portion is basically the shaft 310 which, as described above, supports a series of electrode elements (not shown).

The first and second connector parts 319 and 321 have elements that will mechanically couple the handle to the remaining part of the probe, releasing the two at the desired time. The first and second parts of the connector will also connect signal cables from the electrodes (or other operating elements) and temperature detectors to the power source. A locking mechanism (not shown) can be used to maintain the integrity of the connection between the two parts of the connector. A cable (323) may be arranged to connect the handle to a power source.

The handles shown in Figures 10e-10g can be used with any of the probes that have been disclosed and the characteristics of said handles can be incorporated into any of the other handles that are disclosed in this description.

As shown by way of example in Figures 10h and 10i, and in accordance with one embodiment of the present invention, a remote control unit (325) can be used in conjunction with a surgical probe (308) or a catheter ( not shown). The remote control power unit (325) comprises a main body (327a) and a series of on-off switches (327b). Preferably, there is a start-stop switch (327b) for each of the electrodes and in the embodiment shown there are seven electrodes and seven start-stop switches. The remote control power unit may also include a general start-stop potential switch (not shown). Alternatively, a foot control (not shown) may be provided to perform the same function.

The size and shape of the remote power control unit (325) allow it to be easily held in one hand by the physician or other member of the operating room team. Preferably, the remote power control unit (325) is approximately 20.3 cm (8 inches) long, about 3.8 cm (1.5 inches) wide, and approximately 1.3 cm (0.5 inches) thick. Of course, the dimension and shape can be adjusted to suit specific needs.

The remote power control unit 325 can be used in conjunction with conventional electrophysiology power control units, such as those disclosed in US Patent No. 5,545,193, that are connected to a power source. (such as ablation energy) and provide individual electrode control. To facilitate said use, the remote control device comprises a connection apparatus which, in the embodiment shown, consists of a cable (329a) and a connector (329b). The cable 329a should be relatively long, that is, approximately between 1.8m (6 feet) and 4.6m (15 feet) in length, preferably being 3m (10 feet). The connection apparatus may also take the form of a wireless transmitter / receiver device or any other appropriate device. Surgical probe (308) is also connected to the power control unit for electrophysiology. When the foot control is used it is also connected to the power control unit for electrophysiology.

The exemplary remote power control unit 325 comprises indicators 333 in the form of the remote or distal portion of the surgical probe, indicator lights 335, and numbers corresponding to the respective probe electrodes. the probe. The combination of indicators, lights, and numbers allows the clinician to easily determine which electrodes are activated and which are inactivated.

IS 2 232 688 T3

Surgical probe (308) (as well as other probes disclosed in this description) and remote power control unit (325) are sterilizable. For this purpose, these devices are either completely hermetically sealed or certain parts, such as those comprising electronic components, are sealed. Components that are not sealed can allow the entry of a sterilizing gas, such as ethylene oxide (EtO). Surgical probes and remote power control units must also be splash resistant.

In cases where a malleable shaft (310) is desired, the hypodermic tube (316) may be the heat treated malleable hypodermic tube (316), which is shown in Figures 10a, 12 and 13. By heat treating selectively form certain parts of the hypodermic tube, one section of the hypodermic tube (preferably the distal section) can be made more malleable than the other. This will reduce any discontinuity between distal section (314) and shaft (310) when the distal section is malleable.

A series of temperature sensing elements (such as thermocouples, not shown) can be positioned on the longitudinal end edges of the electrode elements 294, or can be found between them, or placed upside down or abutting. the same, in any of the devices disclosed in this description by way of example. Additionally, a reference temperature sensing element may be provided. For example, a reference temperature sensor (324) can be positioned on the handle so that ambient temperature will be used as a reference, as shown in Figure 10a. The reference temperature sensor may alternatively be arranged at or near the end or distal point of the device. Another alternative is to use an electrical circuit to function as a reference temperature detector. A reference temperature sensor can also be placed on the patient's body or in the operating room, and the physician can simply enter the reference temperature into the power control device. It should be noted that the accuracy of the reference temperature sensor is less important in applications where the patient is in bypass, because the effects of convective cooling of the blood as it passes the electrodes are substantially reduced. Also, the surgical devices of the invention provide better tissue contact than conventional catheter-based devices, which provide more accurate temperature control.

The distal section (314) can be either somewhat flexible, in that it will conform to a surface against which it is pressed and will then regain its original shape when removed from said surface, or, as indicated above, it will be malleable. A bending modulus of 86 N-cm is preferred² (3 lb-in.²) and 1435 Ncm² (50 lb-in.²). As shown by way of example in Figure 11a, a somewhat flexible distal section (314) may include a spring element (330), which is preferably, or a solid flat wire spring (as shown ), a round wire, or a Nitinol three-leaf flat wire spring, which is connected to the distal end of the hypodermic tube (316). Other spring elements formed from materials such as 17-7 stainless steel or so-called "joiner's steel" can also be used. A series of conductors 332 and 334 connect electrode elements 294 and temperature sensing elements, respectively, to panel PC 320. The spring element (330) and the conductors (332) and (334) are contained within a flexible body (336), preferably formed from PEBAX material.^®, polyurethane, or other suitable materials. The spring element 330 can also be pre-tensioned, so that the distal tip is prebent as shown in Figure 10a. Also, an insulating sleeve (331) may be positioned between spring element (330) and conductors (332) and (334).

In cases where a malleable distal portion (314) is desired, the spring element (330) can be replaced by a mandrel (337) made of a suitable malleable material, such as annealed stainless steel or beryllium copper. as shown, for example, in Figure 11b. The mandrel will ideally be attached to the tip or distal end of the device (for example, by welding, spot welding, or adhesives) and will pass through the shaft to the handle, to which it will also be attached, to ensure good transmission of torque. forces and stability of the tip and distal end. Alternatively, the malleable mandrel may be attached directly within the distal end of the hypodermic tube (316) on the shaft or may be attached, for example, by welding, spot welding or adhesives.

Alternatively, and as shown by way of example in Figure 11c, a slot (339) may be formed in the hypodermic tube (316 '). The malleable mandrel (337) is inserted into the slot (339), and is then held in place by the spot welds (341) (shown), soft solder or adhesive. The slot (339) comprises an opening (341) at one of its ends through which the mandrel (337) passes. Slot 339 may also include another opening at the other end. The slot (339) is positioned spaced from the proximal end of the hypodermic tube (316 ') to create additional support for the mandrel (337) when the mandrel (337) is curved and formed into various shapes or structures. By shortening the length of the mandrel (337) the torque of the shaped distal assembly is increased over that previously described, in which the mandrel is anchored within the handle.

The distal part (314) can also be constituted by a hypodermic tube that is simply a continuation of the hypodermic tube (316) of the stem or shaft. However, the distal end hypodermic tube may be a separate element connected to the shaft hypodermic tube (316), if it is desired that the distal end hypodermic tube has different stiffness (or bendability) than the shaft hypodermic tube.

IS 2 232 688 T3

The shaft or stem 310 may be between 10.2 cm and 45.7 cm (4 and 18 inches) in length, and preferably 15.2 to 20.3 cm (6 to 8 inches). The distal portion 314 may have a length of 1 to 10 inches (2.5 cm to 25.4 cm) and is preferably 2 to 3 inches (5.1 to 7.6 cm). To facilitate the formation of long continuous lesions, the distal portion (314) preferably includes six electrode elements (294) spaced from each other, which are approximately 12mm in length. The number and length of the electrode elements 294 can, of course, be varied to suit specific applications.

As shown by way of example in Figures 10b and 10c, the distal section (314) may be provided with a distal electrode (or tip). Referring first to Figure 10b, distal electrode 326 may be a solid electrode with a through hole for one or more temperature sensors. Another exemplary electrode is the envelope electrode (328) shown in Figure 10c, which could also have one or more temperature sensors inside it. Distal electrodes have a number of applications. For example, a distal electrode can be dragged along an anatomical surface to create a long lesion. The distal or remote electrode can also be used to make contact with lesions (straight or curvilinear) created by the electrode elements (294) if, for example, the distal section (314) does not exactly adapt to the anatomical surface, and to continue lesions formed by the electrode elements. The distal electrode can also be used to create acute anatomical ridge or ridge injuries, so that the integrity of the surgical device would be compromised if the distal section (314) were curved to accommodate said ridge or ridge area.

As shown by way of example in Figure 13, an exemplary surgical probe (340) is provided with a pull wire (342) that allows the physician to adjust the curvature of the distal portion (314) from a no-curve situation, up to a slight curve, an extreme curve or even a loop, if desired. The distal portion (344) of the pull wire is connected to the distal or distal tip of the distal section (314). The distal portion of the pull wire enters the stem in the vicinity of the ablation electrodes, and the proximal portion (346) exits through an opening formed in the handle (312). However, for pull wire 342, probe 340 is substantially the same as the spring point probe shown in Figures 10a and 11a. Alternatively, the proximal portion of the pull wire 342 may be associated with a knob / knob device, as shown in FIG. 9f.

As shown, for example, in Figures 14 and 15, a surgical probe (348) is provided with a distal or remote loop structure (350) comprising an operating element (252) in the form of a series of electrodes. (294). The distal loop structure (350), which extends through the opening (352) of the sheath (354), is connected to a stem (356). Said stem is connected, in turn, to the handle (312). The proximal portion of the sheath (354) comprises a handle (358) that allows the sheath to be moved away and closer. The stiffness of the loop structure (350) is less than that of the sleeve (354). As such, when the sleeve (354) is stretched in the proximal direction, the loop structure (350) will bulge out of the opening of the sleeve (352) as shown in FIG. 14. When the sleeve (354) is returned to its furthest position, the loop structure (350) will slide back past the interior of the sleeve such that the sleeve and the loop are coaxial.

The exemplary loop structure 350 is similar to the distal portion 314 of the probe shown in Figures 10a and 11a in that it includes a spring element (not shown), such as a leaf spring or a flat wire spring (preferably formed from Nitinol), which is covered by a flexible material, such as a PEbAx® tube (359). In addition to allowing the distal portion (350) to bulge outward, the spring element can be flat, thereby also providing elasticity that helps the distal portion to conform to the anatomical surface of interest and to prevent "out-bending." flat ”.

In the exemplary embodiment shown in Figures 14 and 15, a pivot assembly (360) is disposed at the distal end of the sleeve (354). The pivot assembly (360) comprises a base member (362) and a pivot member (364), which is secured to the base member by a pivot pin (366). Referring more specifically to FIG. 15, the pivot member (364) pivots within a slot (368) formed in the base member (362). The dimensions and shapes of the slot 368, and the location of the pivot element 364 therein, can be adjusted to adjust the shape of the loop. For example, the location of the pivot element (364) and the shape and dimensions of the slot (368) can be varied such that the pivot element can only rotate 30, 60, 90 or 180 °. However, a rotation up to 270 ° is possible. The pivot element (364) comprises a connector (372) (such as that shown threaded or spiked) to secure the distal end of the loop structure (350) to the pivot element.

The rigidity, malleability, or flexibility of the probe 348 can be achieved in a number of different ways. For example, sheath 354 can be formed from a stainless steel hypodermic tube, a relatively rigid and somewhat flexible stainless steel hypodermic tube, or a relatively rigid and malleable annealed stainless steel hypodermic tube. Additionally or alternatively, shaft 356 may be a rigid (or somewhat flexible) stainless steel hypodermic tube or a malleable annealed stainless steel hypodermic tube. In either case, the distal end (374) of the shaft (356) will abut the flexible portion of the loop structure (350). Other materials can be used, of course, in place of stainless steel. A rigid plastic tube of high hardness, for example, can be a substitute for the hypodermic stainless steel tube in the sleeve or stem.

IS 2 232 688 T3

Once the sleeve (354) and the stem (356) have been positioned relative to each other, so that the desired loop is produced, the sleeve can be attached to the stem by means of a “touhy borst” connector (376) that It is attached to the distal end of the sleeve (354) between the handle (358) and the handle (312).

An ablation probe (378) in accordance with another aspect of the present invention is shown, for example, in Figure 16. The probe comprises a stem (380) (similar to stems (254), (310) and ( 356) described above) on which one or more ablation electrodes (294) have been mounted. As described in greater detail in Section II below, a shield 296 can be used to control the focus of the ablation energy and / or prevent conduction cooling when the probe is in the bloodstream. A handle (266) is also supplied. Stem 380 is preferably approximately 4-16 inches long, approximately 3-8mm in diameter. Furthermore, the stem can be rigid or relatively rigid and, in case it is relatively rigid, it can be malleable or somewhat flexible. The ablation probe (378) can be used for a number of procedures. For example, the stem can be inserted into the heart to perform ablation procedures.

Referring again to Figures 34 and 35, a pressure application probe (650) can be used to apply pressure to the distal section of a probe, such as the probe (308) shown in Figure 10a, or any other device. support of the operating element. Applying pressure with the probe (650) can improve the level of contact between the tissues and, for example, the distal section (314) of the probe (308). The pressure application probe (650) comprises an elongated main body portion (652) and at least one coupling device (654). The exemplary pressure application probe shown in Figures 34 and 35 also comprises a second coupling device (658). As explained in detail below, the second coupling device (658) has a slightly different shape than the coupling device (654).

The main body portion (652) is preferably and alternatively rigid, malleable, or somewhat flexible and approximately 4 to 18 inches in length, although the length is adjustable. to suit specific applications. When a malleable-type main body part is desired, the main body part (652) may be formed in the manner described above with respect to shaft (254), and preferably consists of a soft metal rod or tube. , or a rod or tube of a curable plastic material. For example, shaft 254 can be formed from a nickel titanium rod or tube, which is ductile at room temperature and straightens at elevated temperatures, such as those used during autoclave sterilization. Regardless of stiffness, the outer surface of the main body part (652) must be covered with insulating material, such as PEBAX® or urethane. Coupling device 654 is preferably formed from an insulating material, such as polycarbonate, urethane, fiberglass filled thermoplastic, or ABS.

The coupling device can have any of a number of different configurations. In the exemplary embodiment shown in Figures 34 and 35, the coupling devices 654 and 658 are generally C-shaped, with a coupling device 658 having a more open shape. In use, the C-shape helps to maintain the coupling devices in the desired location on the distal portion of the surgical probe (308) so that pressure can be applied to the desired location. The open shape of the coupling device (658) allows the coupling device to be easily repositioned along the distal portion of the surgical probe without altering the position of the surgical probe relative to the tissues.

The C-shaped coupling device (654) can be attached to the distal section (314) of the probe (308) as shown in Figure 34, or any other probe by inserting the distal tip of the probe. through the opening (656) or by snapping the coupling device (654) onto the distal section. When it is desired to make a snap coupling, the coupling device must be somewhat flexible. This arrangement allows the pressure application probe (650) to rotate relative to the probe (308) when the two are engaged. As a result, the pressure application probe (650) can be reoriented without moving the probe (308). Pressure application probe (650) can also be used to move probe (308) within the patient's body when the two are in contact.

As shown by way of example in FIG. 36, an exemplary pressure application probe (660) is provided with a coupling device (662) having a relatively narrow profile. The narrow profile allows the probe (660) to make contact with the distal section of the operating element support device, such as the distal section (314) of the probe (308), even where the two devices are in contact. oriented at a noticeable angle to each other. Of course, the coupling device is not limited to the shapes shown in Figures 34-36. Any shape capable of engaging the distal portion of a probe can be used.

While there is no limitation on this use, the pressure application probes shown in Figures 34-36 are especially useful in toroscopic procedures. In this case, the pressure application probe can be inserted into the patient's body through one opening, while the electrode support probe is inserted through another opening and is connected to the pressure application probe.

Another device that can be used in conjunction with probes, such as the probe 308 shown in Figure 10a, is shown, for example, in Figure 37. The coupling device 664, by way of example, comprises a base element (666), a general C-shaped coupling device (668) (similar to that shown in

ES 2 232 688 T3 described above) and, in the embodiment shown, a connecting element (670). The base member (666) and the coupling device (668) may also be directly connected to each other.

Coupling device 664 has a wide range of uses. For example, the coupling device may be part of a pressure application probe (672), as shown in Figure 38. Another exemplary use of the coupling device (664) is as shown in FIG. shown in Figure 39. In this case, the coupling device (664) is positioned over a probe, such as the probe (308), which is used to form a distal loop. The coupling device can be located at different points along the length of the probe and arranged in different rotational orientations with respect to the probe (note arrows 674a and 674b), in order to control the shape of the loop. To this end, the base member (666) and a portion of the distal section (314) may include respective sets of teeth that allow the rotational orientation of the coupling device (664) to be set relative to the probe (308). . Observe the teeth (676) in figure 40.

In order to increase the number of coupling device applications, the connecting element (670) can be configured in many ways. For example, connecting element 670 can be rigid, flexible, somewhat flexible, or malleable. The connecting element (670) can also take the form of a hinge or pivot. The base element (666) and the coupling device (668) can also be fixed at different angles to each other (see for example figure 38).

II. Operating elements

A. Operational elements by way of example

In the exemplary embodiments shown in Figures 1-16, the operating element (252) is made up of a series of electrode elements (294). Electrode elements 294 can serve a wide variety of different purposes. Operating elements 252 can also be chemical ablation lumens, laser devices, ultrasonic transducers, microwave electrodes, and direct current hot wires.

In the embodiments shown, the primary use of the electrode elements is to transmit energy, and more particularly, RF energy for ablation of cardiac tissues. However, the electrode elements can also be used to detect electrical events in cardiac tissues. Alternatively or additionally, the electrode elements can serve to transmit electrical pulses to measure the impedance of cardiac tissues, to timing cardiac tissues, or to assess tissue contact using conventional timing and sensing techniques. Once the physician makes contact with the tissues in the desired heart region, the physician applies ablation energy to the electrode elements.

In the exemplary embodiments shown in Figures 1-16, electrode elements (294) are electrically coupled to individual conductors (see reference numeral (295) in Figures 8b and 9e, and numeral (332) in Figures 11a, 11b and 12) to conduct ablation energy thereto. The conductors are passed in a conventional manner through a lumen extending through one of the legs of the reed and stem (254) into a PC panel in the handle (266), where they are electrically coupled to a connector (296) that is housed in an opening (298) (see figure 1). Connector 296 plugs into an ablation RF energy source. A number of temperature sensing elements (not shown), such as thermocouples or thermistors, may be disposed on the tab assemblies shown. These temperature sensing elements can be located on, below, or abutting the extreme longitudinal edges of the electrode elements (294), or between them. For temperature control purposes, signals are transmitted from the temperature sensing elements to the ablation energy source via conductors (see reference numeral (297) in Figures 8b and 9e, and reference numeral (334) in Figures 8b and 9e). Figures 11a, 11b and 12) which are also connected to the panel PC. Suitable temperature sensing elements and controllers that control power to an electrode, based on the sensed temperature, are disclosed in US Pat. No.^you 5,456,682 and 5,582,609. The respective numbers of conductors will, of course, depend on the number of detectors and electrodes used in a specific application. A suitable temperature control system is described below with reference to Figures 28-31.

The electrode elements can be mounted in different ways. For example, they may comprise multiple electrode elements of a rigid general structure, arranged in a segmented relationship, spaced from one another. The segmented electrodes may each comprise solid rings of a conductive material, such as platinum, constituting an interference mount around the annular element of the tab. Alternatively, the electrode segments may comprise a conductive material, such as platinum-iridium or gold, coated onto the device, using conventional coating techniques or an ion beam deposition (IBAD) process. For better adhesion, a nickel or titanium undercoat can be applied. The electrodes can also take the form of helical ribbons.

Alternatively, the electrode elements may comprise spaced spaced lengths of spiral coils wound closely on the device to form a set of generally flexible electrode elements. The coils are made of an electrically conductive material, such as a copper, platinum or stainless steel alloy, or composites, such as tubes with an internal filler (for example, a copper core with a platinum jacket or envelope) . The electrically conductive material of the

ES 2 232 688 T3 coils can also be coated with platinum-iridium or gold to improve their conduction characteristics and biocompatibility.

Electrode elements can be formed with an ink conductive compound that is applied by printing onto a non-conductive tubular body. A preferred conductive ink compound is a conductive ink silver-based flexible adhesive (polyurethane binder), however, other metal-based adhesive conductive inks such as platinum-based, gold-based, gold-based, can also be used to form electrodes copper, etc. These inks are more flexible than epoxy-based inks.

As shown, for example, in Figure 7, the electrode elements may also include a coating of porous material (299), which transmits ablation energy through an electrified ionic medium. For example, as disclosed in US Patent No. 5,991,650, electrode elements and temperature sensing elements can be coated with regenerated cellulose, hydrogel, or plastic, with electrically conductive components. With respect to regenerated cellulose, the coating acts as a mechanical barrier between the components of the surgical device, such as electrodes, preventing the entry of blood cells, infectious agents, such as viruses and bacteria, and large biological molecules, such as proteins, simultaneously providing electrical contact with the human body. The regenerated cellulose coating also acts as a biocompatible barrier between the components of the device and the human body, so that the components can be made from materials that are somewhat toxic (such as silver or copper).

For applications where the ablation electrode is in contact with circulating blood as well as tissues, such as when the patient is not on bypass, the electrode coating with regenerated cellulose decreases the convection cooling effect of the electrode since regenerated cellulose is a poor thermal conductor compared to metal. Thus, the effect of convection cooling by circulating blood past the regenerated cellulose coated electrodes is reduced. This provides better control for a lesion generation process because the highest tissue temperature is in the vicinity of the ablation electrode.

Furthermore, the regenerated cellulose coating reduces the side effects attributed to supplying RF energy to an electrode that has a rough transmission between the conducting electrode and the insulating material. The current density across the electrode and the power density within the tissues are more uniform, reducing the incidence and severity of burns and / or clot formation. A more uniform current density along the axis of the device also results in a more uniform temperature distribution across the electrode, which reduces the requirement for precise placement of the temperature sensors on the ablation electrodes. Additionally, by coating the device with regenerated cellulose to create the outer surface, less cumbersome methods can be used for forming electrodes and bonding conductors to the electrode surfaces.

During the coating process, a device, such as one of the distal tab assemblies described above, is coated with a viscose solution. The viscose solution is preferably cellulose xanthate, which is a form of solubilized cellulose derivative that is dissolved in a sodium hydroxide solution. The viscose solution is applied by dipping into the distal end assembly, which includes the electrodes, signal leads, temperature detectors, etc. The coated device is then regenerated by contacting an acid, such as sulfuric acid, which converts the xanthate back to a cellulose structure. The term "regenerated cellulose" refers to cellulose that has been converted from a solubilized cellulose derivative back into a pure cellulose backbone. This regeneration process creates sufficiently large micropores in the coating that allow sufficiently small ion transport to prevent the entry of blood cells, infectious agents, such as viruses and bacteria, and large biological molecules, such as proteins.

Once the cellulose has been regenerated, it is washed with water to remove acid residues and sulfur compounds. An oxidizing agent (bleach, etc.) can be added to the wash water to accelerate the removal of sulfur compounds. After the cellulose has been regenerated, it is subjected to complete cure in an environmental chamber with reduced humidity. Subsequently, it is preferable to make the regenerated cellulose flexible in the dry state, and to achieve this, moisture is reintroduced into the cellulose coating material by setting the environmental chamber to a higher humidity. Alternatively, a small amount of a material, such as glycerol, can be applied to the coating and the hydroscopic nature of the glycerol will hydrate the cellulose coating creating sufficient flexibility. An overall thickness range for operative regenerated cellulose coatings is 0.25 to 3.8 mm (0.001 inches to 0.015 inches), with a preferred thickness range of 0.25 mm to 0.76 mm (0.001 at 0.003 inch); and the preferred thickness being about 0.51 mm (0.002 inches).

Materials other than regenerated cellulose could be used which have mechanical strength and characteristics suitable for the coating material. Hydrophilic materials having effective pore sizes of 500 to 500,000 Daltons, with a porosity of 1-10%, and which are biocompatible, could be effective. Some types of hydrogels, such as those used for single-use contact lenses, are suitable materials. Plastic materials that have additives can also be used to transform them into semiconductors. The loaded plastic should have a resistance in the approximate range of 200-2,000 ohm-cm, and should be applicable in very thin films to the device.

IS 2 232 688 T3

The thickness of the cellulose coating is controlled by the viscosity of the coating solution and the rate of immersion, and a different viscosity of the coating solution can be achieved by diluting it with a sodium hydroxide solution. Variable wall thickness can be achieved by varying the extraction speed during the dipping process. The lower the extraction speed, the thinner the wall thickness, and the faster the extraction speed, the greater the wall thickness. An increased coating wall thickness can also be obtained by multiple coating layers. To ensure proper lamination between said layers, each layer is coagulated with a salt solution (sodium sulfate, etc.) before applying another layer. Furthermore, spraying and coextrusion of the viscose solution on the electrodes and the distal section can also be used to achieve a variable wall thickness of the cellulose coating.

In another method of coating the distal electrode assembly, a regenerated cellulose tubular shell is created on a mandrel. The regenerated cellulose shell is then inserted into the distal assembly.

The regenerated cellulose coating can also be applied to a "wet" electrode element. The humidity of the wet electrode element prevents the electrode elements from sticking to tissues during the ablation process. A wet electrode is formed by a material that has a high liquid absorption capacity, such as an open cell foam material, hydrogel, or a cloth. Alternatively, the regenerated cellulose coating may simply be wet prior to processing, such as an ablation process.

The electrode elements can be actuated in a unipolar fashion, in which the ablation energy emitted by the electrode elements is returned through an indifferent patch-type electrode (not shown) externally attached to the skin of the patient. Alternatively, the elements can be driven in bipolar mode, in which the ablation energy emitted by one or more electrode elements is returned by other electrode elements. The magnitude of power required for tissue ablation is between 5 to 150 W.

The electrode elements are preferably 4mm to 20mm in length. Patterns of continuous-type lesions result uniformly when adjacent electrode elements are separated by a maximum of 2.5 times the diameter of the electrode segment. Further details for forming long, thin, continuous lesion patterns are found in PCT Publication No. WO 95/10318, entitled "Systems and Methods for Forming Elongated Lesion Patterns in Body Tissue Using Straight or Curvilinear Electrode Elements." ("Systems and methods for modeling elongated injuries in body tissues using straight or curvilinear electrode elements."). Similar sizing and spacing can be used in conjunction with the other embodiments shown.

Using rigid electrode segments, the length of each electrode segment can vary from about 2mm to about 10mm. Using multiple rigid electrode segments with a length greater than approximately 10 mm each has an adverse effect on the overall flexibility of the element. In general, it can be noted that adjacent rigid electrode segments with lengths less than about 2 mm do not continuously form the desired continuous lesion patterns.

When flexible electrode segments are used, electrode segments with a length greater than about 10 mm can be used. The flexible electrode segments can be about 50mm long. If desired, the flexible electrode structure can be continuously extended along the entire length of the support tab.

B. Considerations of operating elements in a refrigeration environment without convection

In the exemplary embodiments shown in Figures 1-6a, 7, 9a-f, 10, 13 and 14, the electrode elements are not hidden. Such embodiments are particularly useful when little or no fluid is present, such as the case where the heart is bypassed and there is no blood flow within the heart. In this case, the air acts as an insulator and produces only moderate convection cooling effects, compared to a circulating bloodstream that has a higher coefficient of convection than virtually static air. The energy transmission is therefore essentially limited to the RF energy transmitted from the part of the electrode surface that is in contact with the tissues to a ground electrode or other electrode within the group of electrode elements. . The overall impedance of the system will increase (compared to where blood is present) due to the reduced effective surface area between the electrode and the tissues.

Both conditions, i.e. concentrated RF energy and low heat dissipation in air, will have an impact on ablation because they result in higher current density with high local heat storage without the heat reduction that convection cooling provides. . When creating large lesions with a conventional catheter, charring can be created by dragging the tip, due to the high current density and difficulty in controlling tissue temperature and power control that are inherent in the process of drag. The present invention, however, can take advantage of a high current density because the electrodes are not entrained. For example, a series of electrodes can be used for simultaneous ablation since the effective surface area (tissue contact) between all of the ablation elements is smaller.

ES 2 232 688 T3 and the effects of convective cooling are small compared to situations where blood is present. This reduces the power demands of the system. In addition, by using electrodes with a lower thermal mass (compared to a conventional solid tip electrode), less heat will be retained by the electrode and better detection of tissue surface temperature can be achieved. This will accelerate injury creation and allow for better control of injury creation.

It should also be noted that the concealment or masking described in the next section can be helpful during bypass, because the tissues may partially wrap around the electrodes when the distal end of the device is pressed against the tissues. This concealment or masking can also be used to control the thickness of the lesions.

C. Considerations of operating elements in a convection cooling environment

In cases where the patient is not on bypass and blood is flowing past the electrodes, or in other situations where fluid flow is available, the part of the electrode elements (or other operating elements ) not intended to contact tissues can be concealed by a variety of techniques with a material that is preferably electrically and thermally insulating. For example, a layer of UV adhesive (or other adhesive) can be painted over preselected parts of the electrode elements to isolate the parts of the elements not intended to contact tissues. Alternatively, a slotted sheath may be disposed over the part of the electrode elements not intended to contact tissues. Also, deposition techniques can be implemented to position a conductive surface only on the portions of the tab assembly to be contacted with the tissues. A coating can be formed by dipping electrode elements in polytetrafluoroethylene (PTFE).

As shown by way of example in Figure 8a, a layer of polymer (296) can be thermally melted onto the electrodes (294) to hide the desired portions of the electrodes. The coating prevents the transmission of ablation energy directly into the bloodstream, and directs the applied ablation energy directly into and into tissues.

Next, an exemplary process for using the polymer layer will be explained. A segment of a tube that constitutes the stem is cut long enough to cover the desired electrodes, and is then divided into halves (or other desired angle) along the axis. One half is placed over the mounted distal section, so that it covers the side of the electrodes to be hidden. A piece of polymeric retraction tube, preferably RNF-100 or irradiated LDPE, is carefully slid over the distal end of the catheter so that the masking tube is not displaced from its placement over the electrodes and so that it ends approximately 2 cm beyond the end of the half tube. The distal end is then heated in a controlled heat source to approximately 204 ° C (400 ° F) so that the masking tube fuses with the distal stem tube along its length. , and in such a way that all its edges are well fused in the tube that constitutes the stem, but they are not fused excessively so that the coated electrodes can perform a punching action. Finally, the polymer retraction tube is split at one end and the assembly is heated to approximately 107 ° C (225 ° F), while the polymer retraction tube is slowly peeled away from the fusion-attached catheter stem. .

Additionally, as shown in Figure 8b, the shape of an electrode 294 'can be such that metallic material in the area that is not intended to contact tissues is removed.

The masking or masking techniques that have been described in the previous paragraphs improve the efficiency, for example, of an ablation process by reducing the surface area of ​​the electrodes and, therefore, the energy required for heating the tissues. Masking or concealment can be used to form a narrow electrode which is desirable in some cases, even when the patient is on bypass. The convection cooling effects of the blood flow past the electrode are also reduced. Furthermore, the transmission of RF energy to unforeseen anatomical parts is prevented. This is especially important in epicardial applications where the ablation electrode elements can be sandwiched between multiple anatomical parts, including, for example, the aorta and pulmonary arteries. Concealment techniques also concentrate the application of ablation energy to help control the characteristics of the lesion.

III. Probe Apparatus Epicardial Applications

The embodiments of the present invention described above (mainly those explained with respect to Figures 10a-14) can be used in a number of epicardial processes. One such procedure is a labyrinth-type ablation procedure to prevent fibrillation of the atrium. A thoracostomy, which is a less invasive surgical procedure than a thoracotomy or median stereotomy, can be used to gain access to the atrium. In this case, relatively small incisions are created in the intercostal space. In each of the incisions, a trocar can be used to provide an access opening to the chest cavity. These openings can be used for viewing with fiber optic cameras, ultrasound, or other viewing devices, as well as for surgical devices that ablate tissue. Surgical devices can, for example, be inserted through openings on the left side of the patient that provide direct access to the atrium.

ES 2 232 688 T3 left. The devices can then be used to create long, thin, curvilinear or annular lesions on the surface of the epicardium. If necessary, the lung lobes can be refracted during the process, inserting an endotracheal tube that inflates the right lung only. The left lung will collapse when the chest is opened.

There are also frequent atrial fibrillation substrates in areas close to the pulmonary veins. Lesions can be created on the surface of the epicardium around the pulmonary veins or between the pulmonary veins. However, there is a certain difficulty associated with access to the epicardium due to the presence of fat deposits in the area of ​​the pulmonary vein. The devices described above can create lesions on the surface of the epicardium in the vicinity of the pulmonary veins because they can penetrate through fat deposits by exerting sufficient force against the surface of the epicardium to compress the remaining fats to a degree that ablation electrodes make contact with the epicardium. However, it is very difficult to achieve adequate contact between the tissues and the electrodes. Therefore, it is preferable to carry out endocardial ablation around or between the pulmonary veins, as described below.

IV. Endocardial applications of probe-type devices

The embodiments of the present invention described above can be used in a number of endocardial processes. To create lesions on the surface of the endocardium, access must be gained to the interior of the left atrium. To obtain thoracostomy access to the left atrium by thoracostomy, a cannula can be inserted through the left atrial appendage or the left atrial free wall. The preferred access point is the left atrial appendage, especially if the physician intends to isolate the left atrial appendage at the end of the procedure. More specifically, and as shown by way of example in Figures 32 and 33, a clammable catheter (642) having movable clamping expansions (644) can be used, which is described in US Patent No. 5,865,791, to capture, pull and stretch the appendage AP. Next, a loop catheter (646) having a loop (648), which is also described in US Patent No. 5,865,791, can be used to bypass the left atrial appendage near the base of the appendage. The clamping catheter facilitates positioning of the loop at the base of the appendix by pulling the appendix through the loop. A needle is then used to puncture the wall of the appendix and access the left atrium. A guide wire is drawn by the needle into the left atrium. The needle is then pulled out, leaving the wire in place. Next, an introducer / dilator combination is introduced over the guide wire into the left atrium. The loop is then tightened around the introducer to prevent blood flow past the introducer into the distal atrial appendage. The dilator is then removed, leaving the introducer as access to the interior of the left atrium.

Instead of the loop technique, a bag-closure cord technique can be used in which sutures are used to tighten the atrial appendage around the introducer.

One of the exemplary devices described above, such as those described with reference to Figures 1-9f, can be inserted into the atrium with its tab flattened. Once inside, the sleeve is retracted so that the tab returns to its predetermined configuration and the ablation process is carried out. The sheath is pushed over the tab when the ablation process is complete, and the device has been removed from the atrium. Similarly, the devices described above with reference to Figures 14 and 15 can be inserted with the loop in the retracted state, while the device shown in Figure 13 can be inserted prior to pulling the wire attached to the tip or distal end. These devices can then be manipulated to cause the loops to form. The ablation process can be carried out next. The devices described above with reference to Figures 10a-c, 12 and 16 only need to be inserted to carry out the procedure. The same is true for the malleable material versions of the exemplary devices of Figures 1-9e.

After completion, the introducer is removed and the loop is tightened to isolate the appendage from the left atrium. The loop can be removed from the probe and left in place to keep the appendix isolated. When using the aforementioned drawstring bag technique, the sutures can be tensioned to isolate the appendix. Alternatively, the appendix can be isolated as described below with reference to Figure 26.

In addition to thoratoscopic procedures, another area of ​​cardiac treatment that will benefit from the present invention is mitral valve repair and replacement (which typically involves a thoracotomy, median stereotomy, or thoracostomy), since atrial fibrillation it can be a complication of mitral disease that occurs before or after mitral valve surgery. More specifically, incisional reentry can develop after surgical procedures (such as mitral valve and thoracostopic processes) in which an incision is made in the wall of the atrium which is then closed by sutures, mechanical closures, or other similar devices. Creating a lesion from the incision at the mitral valve annulus (or other anatomic barrier) will reduce the potential for reentrant spread around the incision and thus terminate atrial fibrillation and / or prevent it from develop atrial fibrillation. For example, if the left atrial appendix is ​​used to access the interior of the left atrium for devices that create lesions on the endocardial surface, an additional lesion must be created from this access site to the mitral valve annulus, so that does not occur

ES 2 232 688 T3 incisional reentry when the incision is closed. This additional process is also applicable for processes in the right atrium using incisions to access the interior of the atrium.

Also, there is a frequency of atrial fibrillation substrates in the vicinity of the pulmonary veins. The creation of long, curvilinear lesions between the pulmonary veins, around single pulmonary veins, and / or from pulmonary veins to the mitral valve annulus, will prevent atrial fibrillation. The device shown by way of example in Figures 1 and 2, having an annular electrode assembly, is especially suitable for positioning ablation electrodes around the internal portion of a pulmonary vein. Alternatively, lesions can be created on the surface of the epicardium around the pulmonary veins or between the pulmonary veins. However, there is some difficulty associated with access to the epicardium due to the presence of fat deposits in the area of ​​the pulmonary vein.

V. Other surgical applications

A surgical procedure using the present invention can be used to reduce the level of bleeding during surgical procedures. The process generally comprises the steps of coagulation (or ablation) of tissues to a predetermined depth and subsequent formation of an incision in the coagulated tissues. Coagulation can be achieved by applying RF energy, for example, with the probe shown in Figure 10a. Since the tissues are clotted, the incision will not cause bleeding.

An exemplary process is the removal of a diseased liver lobe. This is a relatively time-consuming procedure and, using conventional surgical techniques, there is a significant risk of serious bleeding. Using one embodiment of the present invention, the lobe tissues are coagulated to a depth of approximately 3mm to 7mm using RF energy. The coagulated tissues are then cut and separated with a scalpel, electrosurgical device, or other suitable instrument. To avoid bleeding, the depth of the cut should not exceed the depth of the coagulated tissues. The process of tissue coagulation and formation, then an incision in the coagulated tissues can be repeated until the incision reaches the desired depth. In this case, each cycle of coagulation and incision will require approximately 90 seconds, 60 seconds to carry out the coagulation and 30 seconds to carry out the incision.

The present surgical technique is, of course, applicable to surgical procedures, in addition to the removal of a lobe of the liver. Such procedures can involve, for example, the vessel, kidneys, other areas of the liver, heart, skeletal muscles and lungs (such as pulmonary lobotomy), as well as the brain. The present technique is also useful in oncology surgical procedures because cancerous tumors tend to be highly vascularized. An exemplary cancer process is the shrinking of a cancerous tumor.

A surgical tool set includes, among other tools necessary for a specific process, a device for soft tissue coagulation and tissue cutting. Suitable devices for soft tissue coagulation are shown, for example, in Figures 1-27 and 34-40. With respect to the probe shown in Figures 10f and 10g, the part of the probe that includes the second connection zone (321), the stem (310) and a series of electrode elements can be included in the tool assembly. with or without the handle (312 ”). As noted above, scalpels, electrosurgical devices, and other suitable instruments can be used to cut tissue. Preferably, the tool assembly is housed in a sterile package that has a flat, rigid bottom portion and a transparent top that provides tool recesses, thereby providing a ready-to-use surgical kit. . The bottom part can be made up of fibers of Tyvek® spunbonded plastic material, or other suitable materials, which allow the contents of the container to be sterilized after the tools have been sealed inside the container. container.

SAW. Apparatus for applying a clamping force

As shown by way of example in Figures 17-19, a clamping device (382) comprises a pair of clamping elements (384) and (386), which are pivotably fixed to each other by a pin. (388), and a surgical element (252) which may be of the type explained above in section II. In this case, the surgical element consists of a series of ablation electrodes (294). The clamping device (382) also comprises a pair of locking elements (390) and (392) and an electrical connector (394) that can be used, for example, to connect the electrodes (294) to a power source. RF energy. Referring more specifically to FIG. 19, the clamping device 382 may also, if desired, take a longitudinally curved shape. Of course, the overall shape of the fastener or flange will depend on the process for which it is intended.

Certain procedures require the application of a clamping force to the body structure involved, in addition to the operation carried out by the operative element. One such procedure is the isolation of an appendage of the atrium, which is explained in more detail below with reference to Figure 26. As shown, for example in Figure 20, a suitable device (396) to be used in such a procedure includes a handle (398) having a pair of fasteners (400) and (402) that can be moved between Yes. In this exemplary embodiment, the handle elements are pivotally fixed to each other by a pin (404) and comprise respective openings (406) and (408). The handle (308), which is actuated

ES 2 232 688 T3 similar to scissors, is operatively connected to a pair of support members (410) and (412), for example, by a suitable mechanical link located within a housing (414). Actuation of handle 398 causes support members 410 and 412 to move relative to each other creating a clamping force. Of course, other types of handles can also be used which can cause movement of the support elements.

An operating element or surgical element (252) is associated with one or both (as shown) of the support elements (410) and (412). Preferably, the operating element consists of one or more electrode elements (294) suitable for ablation (such as those explained in detail in the previous section II and that can operate in unipolar or bipolar mode) in each of the support elements (410 ) and (412). Of course, the operating element 252 may also consist in whole or in part of other types of electrodes, such as a hot tip to cauterize the walls of the appendix. Electrode elements (294) (or other operating element) can be connected to a surgical control / power bridge device via a connector (416). Conductors extend from the electrode elements (294) through chambers of the support elements (410) and (412), and the handle (398) towards the connector (416).

Referring again to Figure 21, the surgical device (418) is similar to that shown in Figure 20, except that the handle (398) is not connected to the support elements (410) and (412) of the operating element by a mechanical link. Rather, the handle member (420) and the support member (422) form an integral unit, such as the handle member (424) and the support member (426). The integral units are pivotally attached to each other by a pin (428). Thus, while the embodiment shown in Figure 20 is especially useful in situations where thoracostomy is used, the embodiment shown in Figure 21 is especially useful in access for thoracotomy or median sternotomy. In either case, the atrial appendage (or other body part) is grasped (or fixed) in such a way that the surgical device is arranged perpendicularly.

As shown by way of example in Figures 22 and 23, the support elements (432) and (434) of the operative element in the exemplary surgical device (430) are attached to the distal ends of the elements. handle 436 and 438, respectively, such that the support elements are perpendicular to the handle elements. Although the elements of the handle (436) and (438) are fixed, respectively, to the middle part of the support elements (432) and (434) (according to longitudinal view, as shown in figure 23), the Support elements can be offset in one direction or another for specific needs (see figure 23a). Furthermore, as shown, for example in Figures 24a and 24b, the support elements (432 'and 432 ") can also be curved, or they can be L-shaped with an angle Θ comprised approximately between 90 ° and 180 °. . The preferred embodiments shown in Figures 22-24b support the body part so that it is arranged parallel to the surgical device.

The exemplary embodiments of Figures 22-24b may be provided with a clamping device used to grasp the body part or structure and pull it in the proximal direction. As shown, for example, in Figure 25, the clamping device (440) comprises a cylindrical element (442) which is urged in the proximal direction by the spring (444). A pair of clamping jaws (446) extend outwardly from the distal end of the cylindrical member (442). The clamping jaws (446), which can pivot relative to each other, are connected to a rod (448) that passes through the cylindrical member (442) with the ability to slide relative thereto. The rod (448) is urged proximally by the spring (450) which, in turn, urges the clamping jaws (446) proximally against the distal end of the cylindrical member (442). In this way, the clamping jaws (446) are forced into their closed position and the jaws can be loosened, pushing the rod (448) in the distal direction.

VII. Appliance applications that apply a clamping force

The clamp (382) shown by way of example in Figures 17-19, can effect the isolation of a part of the body and facilitate the therapeutic and / or diagnostic effects of the operative element (252). In a process of isolating an atrium appendage, for example, clamp 382 can be used to grasp the atrium appendage and isolate it from the interior thereof. RF energy can then be delivered through electrodes 294 (in unipolar or bipolar mode) to fuse the appendage walls of the atrium together. Thereafter, the clamp can be disassembled, or disconnected, from the RF power source by leaving it in place.

Referring again to Figure 26, an exemplary use of the surgical device 396 shown in Figure 20 is the isolation of an atrial appendage. In this case, the device is inserted into an opening in the chest wall. The appendage of the atrium is captured between the support elements (410) and (412) by actuating the handle (398). RF energy is then transmitted from the electrodes (294) of one support element to the electrodes of the other (bipolar mode), or from the electrodes to an indifferent reference electrode on, for example, a patch (unipolar mode) to Thermally fuse the walls of the atrium appendage to each other and insulate the appendage from the atrium. The surgical device shown in Figures 21-26 can be used in a similar manner.

As shown by way of example in Figure 27, the operating element (such as, for example, the electrodes (294)) can be moved from one side to the other of the support elements (452) and (454) . This offset configuration, which can be used in conjunction with any of the exemplary devices in the figures

IS 2 232 688 T3

20-25, is especially useful in a process of isolation of the appendage of the atrium. In this case, the electrodes (294) are displaced from the side of the support elements (452) and (454), which is close to the interior of the left atrium. By insulating the parts of the support elements that do not support the electrodes, and directing RF energy to the side of the appendix (or other body part) isolated by clamping or clamping force, clots or thrombi will occur due to heating of static blood in the part of the appendix that will be isolated from the bloodstream when the side walls fuse together. Of course, when the patient is on bypass, such concealment or masking is unnecessary unless it is used to create lesions of certain dimensions.

VIII. Power control

A. General

Figure 28 shows, in schematic form, a representative system (500) for applying ablation energy by multiple emitters based, at least partially, on local temperature conditions detected by multiple sensing elements.

In FIG. 28, the multiple sensing elements comprise thermocouples 508, 509, and 510, individually associated with multiple ablation energy emitters, comprising electrode regions 501, 502, and 503. ). The system (500) also includes a common reference thermocouple (511) supported within the coupling element for exposure to the bloodstream. Alternatively, other types of temperature sensing elements may be used such as, for example, thermistors, fluoro-optical detectors, and resistive type temperature detectors, in which case the reference thermocouple 511 would not typically be required.

The system (500) further comprises an indifferent electrode (519) for operation in unipolar mode.

The ablation energy emitters 501, 502, 503 may comprise the previously described rigid electrode segments. Alternatively, electrode regions 501, 502, 503 may comprise a segmented or continuous flexible electrode of wrapped conductor or tape. It should be appreciated that system 500 can be used in association with any ablation element that utilizes multiple independently actuated ablation elements.

The system (500) includes a source (517) of ablation energy. In Figure 28, source 517 generates radio frequency (RF) energy. Source 517 is connected (via a conventional isolated output stage 516) to a set of power switches 514, one for each electrode region 501, 502, and 503. A connector 512 (supported by the probe handle) electrically couples each electrode region 501, 502, 503 to its own power switch 514 and to other parts of the system 500.

The system (500) also includes a microcontroller (531) coupled via an interface (530) to each of the power switches (514). The microcontroller (531) turns on or off a power switch (514) to supply RF power from the source (517), individually to the electrode zones (501), (502) and (503). The supplied RF energy flows from the respective electrode region (501), (502) and (503), through the tissues to the indifferent electrode (519), which is connected to the return path of the isolated output stage. (516).

The power switch 514 and interface 530 configuration may vary according to the type of ablation energy being applied. Figure 29 shows a representative implementation for applying RF ablation energy.

In this implementation, each of the power switches (514) includes an N-MOS power transistor (535) and a P-MOS power transistor (536) coupled between corresponding electrode regions (501), (502) and (503) and the isolated output stage (516) of the power source (517).

A diode (533) carries the positive phase of the RF ablation energy to the electrode area. A diode (534) carries the negative phase of the RF ablation energy to the electrode area. Resistors 537 and 538 bias the N-MOS and P-MOS power transistors 535 and 536 in a conventional manner.

The interface 530 for each of the power switches 514 includes two NPN transistors 539 and 540. The emitter of an NPN transistor (539) is coupled to the gate of the N-MOS power transistor (535). The NPN transistor connector (540) is coupled to the gate of the P-MOS power transistor (534).

The interface for each power switch (514) also includes a control bus (543) coupled to the microcontroller (531). The control bus (543) connects each of the power switches (514) to the digital ground (DGND) of the microcontroller (531). The control bus (543) also includes a power line (+) (+ 5V) connected to the connector of the NPN transistor (539) and a power line (-) (-5V) connected to the emitter of the NPN interface of the transistor (540).

The control bus (543) for each of the power switches (514) further includes an E line_sel. The base of the NPN transistor (539) is coupled to the E line_sel control bus (543). The base of the NPN transistor (540)

ES 2 232 688 T3 is also coupled to line E_sel of the control bus (543) through the Zener diode (541) and a resistor (532). Line E_sel Connect to the cathode of the Zener diode (541) through the resistor (532). Zener diode (541) is selected so that NPN transistor (540) turns on when E_sel exceeds about 3 volts (which for the embodiment shown, is a logical 1).

It should be appreciated that the interface (530) can be designed to manipulate other logic level standards. In the specific embodiment, it is designed to manipulate conventional TTL ("transistor transfer logic") levels.

The microcontroller (531) adjusts E_sel from the control bus (543) to a logic value 1 or 0. At logic value 1, the gate of the N-MOS transistor (535) is connected to the (+) 5 volt line through the NPN transistors (539) . Similarly, the gate of the P-MOS transistor (536) is connected to the (-) 5 volt line through an NPN transistor (540). This conditions power transistors 535 and 536 to conduct RF voltage from source 517 to the associated electrode region. The power switch (514) is "on."

When the controller (531) sets E_sel at a logic value of 0, no current passes through the NPN transistors (539) and (540). This conditions power transistors 535 and 536 to block conduction of RF voltage to the associated electrode region. The power switch (514) is "off".

The system (500) (see figure 28) also includes two analog multiplexers (MUX) (524) and (525). Multiplexers 524 and 525 receive a voltage input from each of thermocouples 508, 509, 510, and 511. Microcontroller 531 controls both multiplexers 524 and 525 to select voltage inputs from temperature sensing thermocouples 508, 509, 510, and 511.

Voltage inputs from thermocouples 508, 509, 510, and 511 are sent to front end signal conditioning electronics. The inputs are amplified by differential amplifiers (526), ​​which read the voltage differences between the copper conductors of the thermocouples (508/509/510) and the reference thermocouple (511). The voltage differences are conditioned by the element (517) and converted into digital codes by the analog-to-digital converter (528). Lookup table (529) converts digital codes to temperature codes. The temperature codes are read by the microcontroller (531).

The microcontroller (531) compares the temperature codes of each thermocouple (508), (509) and (510) with preselected criteria to generate feedback signals. The preselected criteria are entered through a user interface (532). These feedback signals control interface power switches 514 via interface 530, connecting electrodes 501, 502, and 503 in on and off positions, ie, on and off.

The other multiplexer (525) connects the thermocouples (508), (509), (510) and (511) selected by the microcontroller (531) to a temperature controller (515). Temperature controller 515 also comprises front end signal conditioning electronics, as previously described with reference to items 526, 527, 528, and 529. This electronics converts the voltage differences between the copper conductors of the thermocouples (508/509/510) and the reference thermocouple (511) into temperature codes. The temperature codes are read by the controller and compared to preselected criteria to generate feedback signals. These feedback signals control the amplitude of the voltage (or current) generated by the source (517) for supply to the electrodes (501), (502) and (503).

Based on the feedback signals from the microcontroller (531) and the temperature controller (515), the system (500) distributes power to the multiple electrode zones (501), (502) and (503) to establish and maintain a distribution. uniform temperatures across the ablation element. In this manner, the system (500) obtains a safe and efficient formation of a lesion using multiple emitters of ablation energy.

System 500 can control ablation energy delivery in different ways. Some representative modalities will be described below.

B. Individual Amplitudes / Collective Duty Cycle

Electrode regions 501, 502 and 503 will be designated symbolically E (J), where J represents a given electrode region (J = 1 to N).

As described above, each of the electrode regions E (J) has at least one temperature sensing element (508), (509) and (510), which will be designated S (J, K), where J represents the electrode region and K represents the number of temperature sensing elements in each electrode region (K = 1 to M).

In this mode (see Figure 30), the microcontroller (516) operates the power switch interface (530) to supply RF power from the source (517) in multiple pulses of the 1 / N duty cycle.

With pulsating power supply, the amount of power (P_{E (J)}) carried to each of the individual electrodes is as follows:

IS 2 232 688 T3

PE (J) - AMPe (j)² X CYCLE WORKe (j) in which:

AMP_{E (J)} is the amplitude of the RF voltage carried to the electrode region E (J), and CYCLE WORK_{E (J)} is the duty cycle of the pulse, expressed as follows:

WORKCYCLEe (j) = TONe (j) / [TONe (j) + TOFFe (j)] where:

TON_{E (J)} is the time in which the electrode region E (J) emits energy during each pulse period,

TOFF_{E (J)} is the time when the electrode region E (J) does not emit energy during each pulse period.

The expression TON_{E (J)} + TOFF_{E (J)} represents the pulse period for each electrode region E (J).

In this mode, the microcontroller (531) collectively establishes the duty cycle (WORK CYCLE_{E (J)}) of 1 / N for each electrode zone (N equals the number of electrode regions).

Microcontroller 531 can sequence successive power pulses to adjacent electrode regions, such that the end of each duty cycle for the previous pulse overlaps slightly with the start of the duty cycle for the next pulse. This overlap in pulse duty cycles ensures that source 517 applies power continuously, without causing open circuit interruption periods during pulse switching between successive electrode regions.

In this mode, the temperature controller (515) makes individual adjustments to the amplitude of the RF voltage for each electrode region (AMPE (J)), thus individually changing the PE power (J) of the ablation energy transported during the duty cycle to the electrode region, as controlled by the microcontroller (531).

In this mode, the microcontroller (531) cycles through successive data acquisition sampling periods. During each sampling period, the microcontroller (531) selects individual detectors S (J, K), and the voltage differences are read by the controller (515) (via MUX (525)) and converted into temperature codes. TEMP (J).

When there is more than one sensing element associated with a given electrode region, the controller (515) records all the sensed temperatures for the determined electrode region, and selects the highest sensed temperature from among these, which constitutes TEMP (J).

In this mode, the controller (515) compares the temperature TEMP (J) detected locally at each electrode E (J) during each data acquisition period at a given temperature TEMP_set established by the doctor. Based on that comparison, the controller (515) varies the AMPE (J) amplitude of the RF voltage supplied to the electrode region E (J), while the microcontroller (531) maintains the CYCLEWORKE (J) for said electrode region and all other electrode regions, to establish and maintain TEMP (J) in the determined temperature period TEMP_set.

The temperature of the set point TEMP_set It can be varied according to the doctor's criteria and empirical data. A representative predetermined temperature point for cardiac ablation is believed to be in the range of 40 ° C to 95 ° C, with 70 ° C being a preferred representative value.

The way the controller (515) controls AMP_{E (J)} It can incorporate proportional control methods, proportional integral derivative (PID) control methods, or fuzzy type logic control methods.

For example, using proportional control methods, if the temperature detected by the first detector element TEMP (1)> TEMP_set, the control signal generated by the controller (515) individually reduces the amplitude AMP_{E (1)}of the RF voltage applied to the first electrode region E (1), while the microcontroller (531) maintains the collective duty cycle WORK CYCLE_{E (Í)} for the first electrode region E (1) likewise. If the temperature detected by the second detector element TEMP (2) <TEMP_set, the control signal from the controller (515) increases the amplitude AMP_{E (2)} of the pulse applied to the second electrode region E (2), while the microcontroller (531) maintains the collective duty cycle CYCLE WORK_{E (2)} for the second electrode region E (2) same as CYCLE WORK_AND(!), and so on. If the temperature detected by a certain sensing element is at the predetermined temperature point TEMP_set, no changes are made to the amplitude of the RF voltage for the associated electrode region.

Controller 515 continuously processes voltage difference inputs during successive periods of

ES 2 232 688 T3 data acquisition for individual setting AMP_{E (J)} in the electrode region E (J), while the microcontroller (531) maintains the collective duty cycle equally for all electrode regions E (J). In this manner, the embodiment maintains a desired temperature uniformity across the ablation element.

Using a proportional integral differential control (PID) technique, the controller 515 takes into account not only instantaneous changes that take place in a given sample period, but also changes that have occurred in previous sampling periods and the proportion o speed at which these changes vary over time. For this reason, using the PID control technique, the controller (515) will select differently to a determined proportionally large instantaneous difference between TEMP (J) and TEMP_set , depending on whether the difference is getting larger or smaller compared to previous instantaneous differences, and whether the rate at which this difference is changing from previous sampling periods is increasing or decreasing.

C. Calculation of the highest prediction temperature

Due to heat exchange between the tissues and the electrode zone, the temperature sensing elements may not accurately measure the maximum temperature in the zone. The reason for this is that the zone of highest temperature occurs below the surface of the tissues, with a depth of approximately 0.5 to 2.0 mm from the point where the zone of the energy emitting electrode ( and the associated sensing element) make contact with the tissues. If power is applied by heating fabrics too quickly, the actual maximum fabric temperature in this lower surface area can exceed 100 ° C, causing fabric drying and / or micro-explosions.

Figure 31 shows an implementation of a neural network predictor (600), which receives as input the temperature detected by multiple detector elements S (J, K) in each electrode zone, in which J represents a determined electrode zone ( J = 1 to N) and K represents the number of temperature sensing elements in each electrode zone (K = 1 to M). The predictor (600) outputs a prediction temperature of the hottest tissue zone T_Maxpred (t). Controller 515 and microcontroller 531 calculate amplitude and duty cycle control signals based on T_Maxpred (t), in the same way as described using TEMP (J).

The predictor (600) uses a two-layer neural network, although more hidden layers can be used. As shown in Figure 30, predictor 600 includes a hidden first and second layer, and four neurons designated N_(L,_X), where L identifies layer 1 or 2 and X identifies a neuron in that layer. The first layer (L = 1) has three neurons (X = 1 to 3), as indicated below N_(1>1); N₍i,₂₎; and N_(E3). The second layer (L = 2) comprises an output neuron (X = 1), designated N_(2d).

The temperature readings of the multiple detector elements, of which only two have been shown - TS1 (n) and TS2 (n) - for illustrative purposes, are weighted and entered into each neuron N_(OR); N_(E2); and N_(E3) of the first layer. Figure 30 represents the W-shaped weights^L(k,_N), in which L = 1; k is the order of the input detector; and N is the input neuron number 1, 2, or 3 of the first layer.

The output neuron N_(2d) the second layer receives as inputs the weighted outputs of the neurons N_(OR); N₍i,₂₎; and not,₃). Figure 30 represents the output weights as W^l(OR,_X), where L = 0; O is the output neuron 1, 2, or 3 of the first layer; and X is the input neuron number of the second layer. Based on those weighted inputs, the output neuron N_(2d) makes prediction T_Maxpred (t). Alternatively, a sequence of previous read samples from each detector can be used as input. In doing so, a history term would contribute to the prediction of the highest tissue temperature.

The predictor (600) must be formed with a set of known data containing the temperature of the detector elements TS1 and TS2 and the temperature of the hottest region, which have previously been achieved experimentally. For example, using a reverse propagation model, the predictor 600 can be shaped to predict the hottest known temperature from the data set with the least error by means of squares. Once the shaping or adaptation phase has been completed, the predictor (600) can be used for the prediction of Tmaxpred (t).

They can also be used to calculate T_Maxpred (t) other types of data processing techniques. See, for example, US Patent No. 5,906,614.

It should be noted that there are certain considerations to take into account when performing ablation / coagulation procedures in the presence of little or no fluid. These procedures include, for example, procedures that must be performed during a heart bypass. These considerations arise from the fact that the convection cooling effects associated with air are much less than those associated with blood and other fluids. Furthermore, the intimate physical (and thermal) contact between the electrodes and the tissues will allow a relatively free heat exchange between them.

Since electrodes that transmit RF energy have high conductivity, they will be subjected to much less ohmic heating. However, heat will be withdrawn from the tissues towards the electrode when RF power is applied to the tissues, which results in a time delay between the highest tissue temperature and the electrode temperature, as well as a temperature gradient within of the tissues in the vicinity of the su25

ES 2 232 688 T3 surface thereof. The temperature of the electrode will eventually approach the temperature of the tissues. At this point, a relatively small temperature gradient will occur between the highest tissue temperature and the electrode temperature, as well as a relatively small heat transfer between the tissues and the electrode. Accordingly, the temperature control algorithm must take into account the time delay between the temperature of the subsurface tissues and the temperature detected at the electrode. However, usually the difference between the temperatures of the tissues in equilibrium and the detected temperatures can be neglected.

In addition to control considerations, the user interface should also allow the physician to receive an indication as to whether convection cooling will exist, allowing the physician to select the appropriate temperature control algorithm.

The shown and preferred embodiments use computer controlled digital processing to analyze information and generate feedback signals. It should be appreciated that other logic control circuits using microswitches, gates and / or inverters, analog circuits and the like are equivalent to the microprocessor controlled technique, which has been indicated in the preferred embodiment.