Untitled record

ES 2 356 348 T3

DESCRIPTION

Field of Invention

The invention relates generally to nerve and muscle identification and integrity tests, and more particularly to systems and methods for safeguarding against nerve and muscle injury during surgical procedures, identification and evaluation of nerve and muscle integrity after traumatic injuries. , and verification of the range of motion and attributes of muscle contraction during reconstructive surgery.

Background of the Invention

US 5,284,154 discloses an apparatus for locating a nerve and for protecting nerves during surgery. A system according to the preamble of claim 1 is known from US 4,515,168.

Even with today's sophisticated medical devices, surgical procedures are not without risk. The anatomy of each patient is different, requiring the surgeon to be always vigilant regarding these differences so that the desired result is achieved. The positioning of nerves and other tissues in a human or animal body is an example of how the internal anatomy differs from patient to patient. Although these differences may be slight, if the surgeon fails to identify one or more nerves, the nerves can be damaged, stretched, or cut during an operation. The negative effects of nerve damage can range from lack of feeling in that part of the body to loss of muscle control.

Traumatic injuries often require surgical repair. Determining the extent of muscle and nerve injury is not always possible using visual inspection. The use of an intraoperative stimulator allows an accurate assessment of the neuromuscular system in that area. This assessment provides valuable knowledge to guide restorative / reconstructive surgery after traumatic injury, and when performing a wide range of surgeries.

Summary of the Invention

According to the present invention there is provided a tissue stimulation system according to claim 1.

The invention provides devices for intra-operative stimulation. Intra-operative stimulation allows precise evaluation of the neuromuscular system to guide reconstructive or reconstructive surgery.

Additional aspects of the invention provide a tissue stimulation system that can be sterilized and prepackaged for single use. The stimulation signal from the tissue stimulation system includes an amplitude that can range from about zero milliamps to about 20 milliamps, allowing for precise selective stimulation of muscles and nerves, as well as identification of muscles and nerves, muscle junctions, or contracting. muscles to assess the quality of surgical interventions. The duration of the tissue stimulation signal may include a range between about zero microseconds and about 200 microseconds, for example. The first cue delivered by the tissue stimulation system may include, for example, auditory and visual cues. The tissue stimulation system may further include a second indication means to provide confirmation of energy to the device and delivery of a stimulation signal to the electrically conductive surface. In one embodiment, the electrically conductive surface of the probe comprises between about 1 millimeter and about 10 millimeters from the distal end of the probe, and the probe comprises a diameter between about 0.5 millimeters and about 1 millimeter. The tissue stimulation system may further include a return electrode electrically coupled to the stimulation control device.

Another aspect of the invention provides devices, systems, and methods comprising a stimulation monitor or probe and at least one electrode. In one embodiment, a handheld monitor or probe includes the stimulation control devices and at least one stimulation electrode within a unitized housing to provide an ergonomic stimulation device. The manual stimulation probe may be a single-use sterile instrument intended for use during surgical procedures to identify nerves and muscles, muscle attachments, or to contract muscles to assess the quality of surgical interventions or the need for surgical interventions, or to evaluate the function of nerves already identified by visual or acoustic means, or by other instruments that monitor the nervous system.

Characteristics and advantages of the invention are set forth in the following Description and Drawings, as well as the added description of technical characteristics.

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Brief Description of Drawings

Fig. 1A is a perspective view showing the stimulation control device in use with a stimulation probe.

Fig. 1B is a perspective view with a cut away and in section showing the stimulation probe having the stimulation control device integrated within the stimulation probe, and showing an optional needle-type electrode.

Fig. 2 is a block diagram of a circuit that the stimulation control device shown in Figs. can incorporate.

Description of Preferred Realizations

This Specification discloses various systems and methods for safeguarding against injury to nerves, muscles, and tendons during surgical procedures or confirming the identity of nerves, muscles, and tendons and evaluating their function or the function of muscles enervated by those nerves. The systems and methods are particularly well suited to assist surgeons in identifying nerves and muscles to ensure nerve and muscle integrity during medical procedures.

Desirably the systems and methods allow the application of a stimulation signal at levels high enough for the purpose of stimulating and evaluating nerve or muscle, or the integrity of both nerve and muscle in numerous medical procedures, including, but not limited to, evaluating the proximity to a specific tissue region, assess proximity to a nerve, or to identify nerve tissue, assessing whether a nerve is intact (e.g. g., after traumatic injury) to determine if repair may be needed, evaluating muscle contraction to determine whether or not the muscle is innervated and / or if the muscle is intact and / or if the muscle is cut, and assessing the muscle and tendon length and function after tendon repair or transfer prior to completion of a surgical procedure.

Furthermore, it should be appreciated that the disclosed systems and methods are applicable for use in a wide variety of medical procedures with a wide variety of medical devices. By non-limiting example, the various aspects of the invention have application in procedures requiring ambitious medical devices as well as internal vision devices.

Figs. 1A and 1B show various embodiments of a manual stimulation probe or monitor 100 for identification and testing of nerves and / or muscles during surgical procedures. The stimulation probe 100 is preferably a single-use sterile instrument intended for use during surgical procedures to identify nerves and muscles, or to contract muscles to assess the quality of surgical interventions or the need for surgical interventions, or to assess nerve function. already identified by visual means.

The stimulation probe is preferably sized small enough to be grasped and used with one hand during surgical procedures. The angle of the stimulation tip facilitates access to both deep and superficial structures without the need for a large incision. A visual or acoustic indicator 126 incorporated into the housing provides reliable feedback to the surgeon regarding the request and delivery of stimulus current.

In one embodiment, the stimulation probe 100 includes a housing 112 carrying an insulated conductor 124. The insulated conductor 124 connects to an electrode 110 positioned at the distal end 114 of the housing. The insulated conductor 124 within housing 112 is isolated from housing 112 using common isolation means (eg, wire insulation, washers, glands, spacers, sleeves, and the like). Electrode 110 is positioned in electrically conductive contact with at least one muscle, or at least one nerve, or at least one muscle and nerve.

In a further embodiment, the stimulation probe 100 is monopolar and is equipped with a single electrode 110 at the proximal end 114 of the housing. Electrode 110 can be any of a variety of electrode types (eg, paddle, wire, surface), depending on the surgical procedure being performed. In an alternative embodiment, the stimulation device 100 itself may be bipolar, which precludes the use of the return electrode 130.

As shown in Figs. 1A and 1B, stimulation probe 100 can accommodate within housing 112 the electrical circuitry of a stimulation control device 22. In this arrangement, stimulation probe 100 can have two operational slide controls, 155 and 160. Current switch 155 serves a dual purpose of feeding and cutting the feed signal to probe 100, and can also be moved to control the amplitude selection of the stimulation signal within a predefined scale (e.g., 0 , 5, 2.0, and 20 mA). Pulse control switch 160 allows adjustment of the duration of the stimulation signal pulse from a predefined scale (eg, 0 to 200 microseconds).

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An operating element, such as a stimulus probe 110, exits the housing at distal end 114 to supply stimulus current to excitable tissue. The probe or electrode 110 comprises a length and a diameter, and is desirably fully isolated with the exception of the most distal end, e.g. eg, about 1.0 millimeters to about 10 millimeters, and desirably from about 4 millimeters to about 6 millimeters, which is not isolated and serves as a stimulus surface to allow the surgeon to deliver the stimulus current only to the intended tissue. The small area of ​​the probe (the active electrode) ensures a high current density that will stimulate nearby excitable tissue. The probe diameter can range from about 0.5 millimeters to about 1.0 millimeters, and can desirably be about 0.75 millimeters.

In monopolar operation, a return electrode (or indifferent electrode) 130 provides an electrical path from the body to the control device 22. The return electrode 130 may be positioned on the intact skin surface (eg, surface electrodes such as those used to monitor ECG during surgical procedures) or it could be live needle 131 (see Fig. 1B), and be placed in the surgical field or penetrate through intact skin. The proximal end 118 of the housing may incorporate a connector or jack 120 that provides options for return current paths, such as by a surface electrode 130 or a needle electrode 131, having an associated plug 122.

Additionally, device 100 may desirably incorporate an acoustic or visual indicator 126 for the surgeon. This visual or acoustic indicator 126 allows the surgeon to confirm that the stimulator 100 is supplying stimulus current to the tissue it is contacting. By using different tones, colors, different flash rates, etc., the indicator 126 (which may have the form p. g., from an LED) allows the surgeon to confirm that stimulation tip 110 is in position, the instrument is connected, and that stimulus current is flowing. Thus the surgeon has much greater confidence that the failure to cause muscle contraction is due to a lack of viable nerve tissue near the tip of stimulator 100 rather than a lack of connection of the return electrode or some instrumentation problem.

The acoustic feedback also makes possible the provision of assisting the surgeon with monitoring the integrity of the nerve during surgery. Insulated conductor 124 connects to an electrode 110 which, in use, is positioned within the surgical field on a nerve distal to the surgical site. Stimulation of the nerve causes muscle contraction distally. The stimulation control device 22 can be programmed to provide an acoustic tone followed by a stimulation pulse at prescribed intervals. The acoustic tone reminds the surgeon to observe the distal muscle contraction to confirm upon stimulation that the nerve is intact and functioning.

Manual stimulation probe 100, as discussed above, can be used to locate a nerve in a patient by connecting a patient to first electrode 110 and second electrode 130, moving current switch 155 to an on position that gives place where a stimulation signal 29 is generated by the stimulation control device 22 and transmitted to the first electrode 110, through the patient's body to the second electrode 130, and back to the stimulation control device 22.

As FIG. 2 shows, stimulation control device 22 includes a circuit 32 that generates stimulation electrical waves. A battery 34 internal to stimulator 100 desirably supplies power. The pulse generator 28 also desirably includes a programmable embedded microprocessor 36, which carries embedded code. The code expresses pre-programmed rules or algorithms for generating the desired waves of electrical stimulation using the stimulus output circuit 46 and for operating the visible or audible indicator 126 based on controls actuated by the surgeon.

In one form, the size and configuration of the stimulation control device 22 makes for an inexpensive device, which does not have manual internal circuit adjustments. It is likely that stimulation control device 22 of this type will be manufactured using automated circuit board assembly equipment and methods.

According to a desirable technical feature, the stimulation control device may be small enough in size to be grasped and used by one hand during surgical procedures. The angle of the stimulation tip facilitates access to both deep and superficial structures without the need for a large incision. The visual or acoustic indication built into the housing provides reliable feedback to the surgeon regarding the request and delivery of stimulus current.

According to a desirable technical feature, power is supplied by a single-use main battery mounted within the housing on or near circuit board 22.

According to a desirable technical feature, stimulation control device 22 desirably uses a standard commercially available flash programmable micro-power microcontroller 36. The microcontroller 36 reads the controls operated by the surgeon, controls the rhythm of the

ES 2 356 348 T3 stimulus pulses, and controls feedback to the user about the instrument situation (eg, an LED or 1, 2 or more colors that can be on, off, or flashing).

The microcontroller operates at low voltage and low power. The microcontroller sends low-voltage pulses to the stimulus output stage that converts these low-voltage signals to stimulus pulses of higher voltage, controlled voltage, or controlled intensity that are applied to the electrode circuit. This stimulus output stage typically involves the use of a series capacitor to prevent the presence of direct current flow in the electrode circuit in normal operation or in the event of an electronic component failure.

The foregoing is considered only as illustrative of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described.