Radial coil expandable medical wire

TECHNICAL FIELD

[0001] The invention generally relates to deployable medical devices for insertion into anatomical lumens.

BACKGROUND INFORMATION

[0002] Blockages and obstructions can develop in certain areas of the body, such as in the kidneys, pancreas, esophagus, and gallbladder. Minimally invasive medical procedures generally cause limited trauma to the tissue of a patient and can be used to eliminate problematic obstructions. Lithotripsy and ureteroscopy, for example, are used to treat urinary calculi, e.g., kidney stones, in the ureter of patients.

[0003] Lithotripsy is a medical procedure that uses energy in various forms, such as acoustic or electrical shock waves, pneumatic or hydraulic pulsation, or laser beams, to break up biological concretions, such as urinary calculi. The force of the energy, when applied either extracorporeally or intracorporeally, usually in focused and continuous or successive bursts, comminutes a kidney stone into smaller fragments that may be extracted from the body or allowed to pass through urination. With the help of imaging tools, such as transureteroscopic video technology and fluoroscopic imaging, the operator of the lithotripter device can monitor the progress of the medical procedure and terminate treatment when residual fragments are small enough to be voided or removed. Examples of such obstructions and the effects of treatment can be found in the published patent application US 2001/0031971, the disclosure of which is incorporated by reference herein in its entirety.

[0004] Intracorporeal fragmentation of urinary calculi can prove problematic, because stones and/or stone fragments in the ureter may become repositioned closer to and possibly migrate back toward the kidney, thereby requiring further medical intervention to prevent aggravation of the patient's condition.

[0005] Many known stone extraction devices are rigid and lack the maneuverability and flexibility to engage and disengage repeatedly a stone without harming the surrounding tissue. For example, if a stone is still too large to be extracted without further fragmentation, it can be difficult to disengage the stone from such an extraction device without damaging the delicate lining of the ureteral wall.

SUMMARY OF THE INVENTION

[0006] The invention generally relates to preventing migration of material during a medical procedure, and to safely and efficiently ensnaring and extracting material from a body. It is desirable to be able to extract such material from the body using a single instrument, which prevents the need for successive instrumentation. A medical device according to the invention can be used to repeatedly ensnare and extract or sweep material (such as stones, stone fragments, and other biological and/or foreign material) while minimizing trauma to surrounding tissue. Accordingly, the device can be deployed and collapsed repeatedly, as and when required during the medical procedure.

[0007] In one aspect, the invention is directed to a medical device including an elongate core and an elongate sleeve. The sleeve includes a lumen that extends longitudinally within at least a portion of the elongate sleeve. The core is slidably disposable within the lumen of the sleeve. The sleeve also includes a plurality of coils that are configured in a conical shape when the core is removed from a section of the lumen extending through the plurality of coils. The sleeve assumes a substantially linear configuration when the core is inserted within the section of the lumen extending through the plurality of coils.

[0008] The conical shape formed by the plurality of coils can be used to ensnare objects in an anatomical lumen. When the sleeve is in the substantially linear configuration, a portion of the sleeve can be advanced beyond an object in an anatomical lumen. The coils can then be allowed to assume their conical shape by removing the slidable core to form a structure capable of ensnaring objects in the anatomical lumen. The core can be extended back through the lumen of the sleeve to return the sleeve into the substantially linear configuration for repositioning the device in the anatomical lumen. The conical shape can then be redeployed by retracting the core from the section of the lumen extending through the plurality of coils. Thus, reversible transformation of the coiled and linear configurations of the sleeve can facilitate repeated positioning and deployment of the medical device in appropriate locations in an anatomical lumen.

[0009] In one embodiment of the invention, the plurality of coils forming a conical shape are located a predetermined distance from a proximal end of the sleeve. In another embodiment, the sleeve further includes at least one coiled element located in a portion of the sleeve distal to the plurality of coils. The at least one coiled element forms when the core is removed from a section of the lumen extending through the at least one coiled element and assumes a substantially linear configuration when the core is inserted into the section of the lumen extending through the at least one coiled element. The at least one coiled element can be used for anchoring the medical device and the conical shape can be used for ensnaring objects in the anatomical lumen.

[0010] In another aspect, the invention is directed to a medical device including an elongate sleeve and an elongate core. The elongate sleeve includes a first portion and a second portion that is more rigid than the first portion and a lumen that extends longitudinally within at least a portion of the elongate sleeve. The core is slidably disposable within the lumen and includes a section that changes shape when disposed within the first portion of the sleeve causing an outer diameter of the sleeve to increase. The core is retained in a substantially linear configuration when the section that changes shape is disposed in the second portion of the sleeve.

[0011] The first portion and the second more rigid portion of the sleeve can have different wall thicknesses. In one embodiment, the first portion of the sleeve has a wall thickness substantially less than the wall thickness of the second portion of the sleeve. In another embodiment, the first portion includes an expandable balloon. In yet another embodiment, the section that changes shape forms a coiled configuration when disposed in the first portion.

[0012] In yet another aspect, the invention is directed to a medical device that includes an elongate sleeve and an elongate core. The sleeve includes a lumen that extends longitudinally within at least a portion of the elongate sleeve and a sleeve section that changes shape. The elongate core is slidably disposable within the lumen of the sleeve and includes a core section that changes shape. Each of the sleeve and core sections retain a substantially linear configuration when restrained and form a substantially coiled configuration when aligned. The sleeve and core sections form a substantially coiled configuration when unrestrained.

[0013] In one embodiment, the coiled configuration of both the sleeve and the core can be substantially equal in shape and size. In another embodiment, each of the sleeve and core sections are adapted to remain in the coiled configuration when at least partially aligned. In yet another embodiment, each of the sleeve and core sections retain the substantially linear configuration when at least partially misaligned.

[0014] In various embodiments of the two foregoing aspects of the invention, the sections that change shape can include at least one coil. The sections that change shape can also include a plurality of coils that form different shapes, such as conical, spherical, helical, frusto-conical, or combinations thereof. In a particular embodiment, the shape formed by the plurality of coils is a generally conical shape.

[0015] In all the foregoing aspects of the invention, the core and the sleeve can be made from the same or different materials. In one embodiment, the sleeve includes a shape-memory material. In another embodiment, the core includes a shape-memory material. In yet another embodiment, both the sleeve and the core include a shape-memory material. Shape-memory materials are materials that can be formed into a particular shape, retain that shape during resting conditions, (e.g., when little or no external forces are applied to the shape), be deformed into a second shape upon subjecting the initial shape to a sufficiently high external force, and revert back to substantially the initial shape once the external forces are removed or at least lessened. Examples of shape-memory materials include synthetic plastics, stainless steel, and superelastic, metallic alloys, such as nickel/titanium (commonly referred to as nitinol), copper, cobalt, vanadium, chromium, and iron.

[0016] In addition, the sleeve and the core can have essentially any cross-sectional shape, such as polygonal, arcuate, or combinations of polygonal and arcuate elements. In the present application, the term polygonal is used to denote any shape including at least two line segments, such as rectangles, trapezoids, and triangles. Examples of arcuate shapes include circular and elliptical. Further, the sleeve can include a coating disposed on an external surface of the sleeve. The coating can be a polymeric material, for example, polytetraflouroethylene, expanded polytetraflouroethylene, ethylene-tetrafluoroethylene, and silicone. The coating can cover a substantial portion of the external surface of the sleeve.

[0017] These and other objects, along with advantages and features of the present invention herein disclosed, will become apparent through reference to the following description, the accompanying drawings, and the claims. Furthermore, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which:

[0019]FIG. 1A is a partially sectioned schematic view of one embodiment of a medical device in accordance with the invention;

[0020]FIG. 1B is another partially sectioned schematic view of the medical device of FIG. 1A, with a sleeve in a substantially linear configuration;

[0021]FIG. 1C is a cross-sectional view of the medical device of FIG. 1A taken at line <b>1</b>C-<b>1</b>C;

[0022]FIG. 2A is a cross-sectional schematic view of the medical device of FIG. 1A with the invention positioned inside the anatomical lumen;

[0023]FIG. 2B is a partially sectioned schematic view of the medical device of FIG. 2A deployed within the anatomical lumen;

[0024]FIG. 2C is another partially sectioned schematic view of the medical device of FIG. 2A deployed within the anatomical lumen;

[0025]FIG. 3A is a partially sectioned schematic view of another embodiment of a medical device in accordance with the invention;

[0026]FIG. 3B is cross-sectional schematic view of the medical device of FIG. 3A, with a sleeve in a substantially linear configuration;

[0027]FIG. 4A is a cross-sectional schematic view of yet another embodiment of a medical device in accordance with of the invention;

[0028]FIG. 4B is a cross-sectional schematic view of the medical device of FIG. 4A taken at line <b>4</b>B-<b>4</b>B;

[0029]FIG. 5A is a cross-sectional schematic view of an elongate sleeve for use with an embodiment of a medical device in accordance with the invention;

[0030]FIG. 5B is a schematic view of an elongate core for use with an embodiment of a medical device in accordance with the invention;

[0031]FIG. 5C is a cross-sectional schematic view of a medical device including the elongate sleeve of FIG. 5A and the elongate core of FIG. 5B;

[0032]FIG. 5D is a partially sectioned schematic view of the medical device of FIG. 5C in one possible deployed configuration;

[0033]FIG. 5E is another partially sectioned schematic view of the medical device of FIG. 5C in another possible deployed configuration;

[0034]FIG. 6A is a partially sectioned schematic view of another embodiment of a medical device in accordance with the invention, wherein each of the sleeve and core sections are in a coiled configuration;

[0035]FIG. 6B is a cross-sectional schematic view of the medical device of FIG. 6A, with each of the sleeve and core sections restrained in a substantially linear configuration;

[0036]FIG. 6C is a partially sectioned schematic view of the medical device of FIG. 6A, with the sleeve and core sections in aligned and coiled configurations;

[0037]FIG. 7A is a schematic view of a spherically shaped coil configuration;

[0038]FIG. 7B is a schematic view of a helically shaped coil configuration; and

[0039]FIG. 7C is a schematic view of a pigtail shaped coil configuration.

DESCRIPTION

[0040] Embodiments of the present invention are described below. The invention is not limited to these embodiments, and various modifications to the disclosed embodiments are also encompassed by the invention. A medical device according to the invention can be used to entrain biological and/or foreign material during a medical procedure. The medical procedure can involve the fragmentation of the material. The device can also be used to remove the material and/or fragments of the material safely from the body. In addition, the device can be used as a self-anchoring guide wire.

[0041]FIGS. 1A and 1B depict a medical device <b>100</b> in accordance with the invention in two different configurations. The medical device <b>100</b> includes an elongate sleeve <b>104</b> and an elongate core <b>102</b>. The sleeve <b>104</b> includes a lumen <b>106</b> that extends longitudinally within at least a portion of the sleeve <b>104</b>, a distal end <b>112</b>, and a proximal end <b>114</b>. In one embodiment the sleeve includes an outer wall <b>103</b> and an inner wall <b>105</b>. The core <b>102</b> is adapted to be disposed within the lumen <b>106</b> of the sleeve <b>104</b>. At least a portion <b>110</b> of the sleeve <b>104</b> is adapted to form a plurality of coils <b>108</b> disposed in a conical shape when the core <b>102</b> is removed from a section of the lumen <b>106</b> that extends through the plurality of coils <b>108</b> (FIG. <b>1</b>A). The plurality of coils <b>108</b> are straightened and the sleeve <b>104</b> assumes a substantially linear configuration when the core <b>102</b> is inserted within the section of the lumen <b>106</b> extending through the plurality of coils <b>108</b> (FIG. 1B). The proximal end <b>118</b> of the plurality of coils <b>108</b> is located a predetermined distance <b>116</b> from the proximal end <b>114</b> of the sleeve. The medical device <b>100</b> is configured to support the treatment and/or removal of foreign objects and organic material, e.g., blood clots, tissue, and biological obstructions, such as urinary, biliary, and pancreatic stones, from an anatomical lumen.

[0042] The sleeve <b>104</b> is constructed, at least in part, of a shape-memory material that enables the sleeve <b>104</b> to assume a coiled configuration forming a conical shape when the core <b>102</b> is removed from the section of the lumen <b>106</b> extending through the plurality of coils <b>108</b>. The shape-memory material of the sleeve <b>106</b> also enables the plurality of coils <b>108</b> to assume a substantially linear configuration when the core <b>102</b> is extended through the section of the lumen <b>106</b> extending through the plurality of coils <b>108</b>, as shown in FIG. 1B, without significantly affecting the ability of the sleeve <b>104</b> to revert back into the coiled configuration when the core <b>102</b> is removed from the section of the lumen <b>106</b> extending through the plurality of coils <b>108</b>.

[0043] Shape-memory materials suitable for use in forming the sleeve <b>104</b> include plastics, stainless steel, and metallic alloys of nickel, titanium, cooper, cobalt, vanadium, chromium, and iron. In one embodiment, the shape-memory material forming the sleeve <b>104</b> is a superelastic material, such as nitinol, which is a nickel-titanium alloy. The core <b>102</b> can also be made from a shape-memory material, such as nitinol. Other suitable materials for the manufacture of the sleeve or the core include: thermoplastic polyurethane (TPU), thermoplastic polyester elastomers, nylons, and equivalent materials. Additional suitable materials will be apparent to those skilled in the art.

[0044]FIG. 1C is a cross-sectional view of the medical device <b>100</b> of FIGS. 1A and 1B. In the embodiment shown, the medical device <b>100</b> has a generally circular cross-section; however, the cross-section could be polygonal, arcuate, or combinations of arcuate and polygonal elements. FIG. 1C depicts the core <b>102</b> disposed within the lumen <b>106</b> of the sleeve <b>104</b>. In one embodiment, the sleeve includes an outer wall <b>103</b> and an inner wall <b>105</b>.

[0045] FIGS. <b>2</b>A-<b>2</b>C depict a medical device <b>100</b>, positioned within an anatomical lumen <b>124</b> of a patient. The plurality of coils serve as a physical barrier or backstop during the lithotripsy procedure to ensure that the smaller fragments do not migrate in an undesired direction, e.g., back toward the kidney. The instrumentation used to perform the lithotripsy can be introduced into the desired location adjacent to the obstruction via another catheter or guide wire.

[0046] In one aspect, a health care practitioner inserts the medical device <b>100</b> within an anatomical lumen <b>124</b>, such as a ureteral passage, to ensnare fragments of stones resulting from a lithotripsy procedure or other objects obstructing the lumen. In this aspect, the plurality of coils <b>108</b> is deployed into a conical shape within the anatomical lumen <b>124</b> by retracting the core <b>102</b> from within the lumen <b>106</b> of the sleeve <b>104</b>, as depicted in FIG. 2B. The medical device <b>100</b> can be inserted into an anatomical lumen <b>124</b> of a patient via a catheter or a guide wire. In one method of use of the medical device <b>100</b>, a health care practitioner inserts the medical device <b>100</b> into an anatomical lumen <b>124</b> with the sleeve <b>104</b> in a substantially linear configuration and the core <b>102</b> extended through the section of the lumen <b>106</b> that extends through the plurality of coils <b>108</b>, as shown in FIG. 2A. For example, in a lithotripsy procedure to remove a kidney stone from a patient's ureter, the medical device <b>100</b> is introduced into the patient's urinary passage until the distal end <b>112</b> passes beyond the location of the stone <b>126</b> lodged in the ureter. The health care practitioner then deploys the plurality of coils <b>108</b> downstream of the stone <b>126</b> by retracting the core <b>102</b> from the section of the lumen <b>106</b> extending through the plurality of coils <b>108</b>, as depicted in FIG. 2B. The plurality of coils <b>108</b> act as a backstop to prevent the migration of the fragments, as shown in FIG. 2B. The maximum outside diameter <b>120</b> of the plurality of coils <b>108</b> is designed to be substantially the same as or slightly greater than the inside diameter of the anatomical lumen <b>124</b> so that the passage will be sufficiently occluded to prevent any subsequent migration of the kidney stone <b>126</b>.

[0047] Once the lithotripsy procedure is complete, the health care practitioner can extend the core <b>102</b> through the section of the lumen <b>106</b> that extends through the plurality of coils <b>108</b> in order to straighten, reposition and redeploy the plurality of coils to ensnare the fragments, as shown in FIG. 2C. If the fragments are small enough to pass through the anatomical lumen, the health care practitioner can drag the fragments from the anatomical lumen and out of the body. If, however, the fragments of the stone are still too large to pass through sections of the anatomical lumen, the sleeve <b>104</b> can be straightened by extending the core <b>102</b> through the section of the lumen <b>106</b> that extends through the plurality of coils <b>108</b>. In this scenario, the health care practitioner can repeat the treatment procedure by repositioning and redeploying the plurality of coils <b>108</b> beyond the stone <b>126</b> and performing a second lithotripsy procedure to further fragment the remaining obstructions.

[0048]FIG. 3A is a depiction of another medical device <b>200</b> in accordance with the invention. The sleeve <b>104</b> can include a plurality of coiled configurations, for example, a first plurality of coils <b>108</b> and a second plurality of coils <b>202</b>. In one embodiment, the second plurality of coils <b>202</b> is located distally to the first plurality of coils <b>108</b> and formed in a portion <b>210</b> of the sleeve <b>104</b>. Each plurality of coils could form a variety of shapes, such as conical, spherical, helical, frusto-conical or combinations thereof. As discussed above with respect to the first plurality of coils <b>108</b>, the second plurality of coils <b>202</b> also forms a shape when the core <b>102</b> is removed from a section of the lumen <b>106</b> extending through the second plurality of coils <b>202</b> and assumes a substantially linear configuration <b>210</b> when the core <b>102</b> is extended through the section of the lumen <b>106</b> that extends through the second plurality of coils <b>202</b>.

[0049]FIG. 3B depicts the sleeve <b>104</b> in a substantially linear configuration, where the core <b>102</b> has been extended through the section of the lumen <b>106</b> that extends through the plurality of coils <b>108</b> and the section of the lumen <b>106</b> that extends through the second plurality of coils <b>202</b>. A device including two separate pluralities of coils is especially useful for the removal of two separate obstructions lodged within an anatomical lumen at the same time. A health care practitioner can insert the medical device inside a patient in a substantially linear configuration, shown in FIG. 3B, with the distal end <b>112</b> of the medical device beyond an obstruction distal to an obstruction proximal to the distal end <b>112</b> of the medical device. The health care practitioner can subsequently withdraw the core <b>102</b> from the lumen <b>106</b> of the sleeve, resulting first in the deployment of the second plurality of coils <b>202</b> encasing the distal obstruction followed by the deployment of the first plurality of coils <b>108</b> that would capture the proximal obstruction. This way, the health care practitioner uses the medical device <b>200</b> to sweep both obstructions out of the patient's body, without having to redeploy the device.

[0050]FIG. 4A is another medical device <b>300</b> in accordance with the invention, where an external surface <b>302</b> of the sleeve <b>104</b> is covered by a polymeric material or sheath <b>304</b>. The polymeric material <b>304</b> can be spray coated onto the external surface <b>302</b> of the sleeve <b>104</b>. Alternatively, a polymer sheath <b>304</b> can be heat-shrunk onto the external surface <b>302</b> of the sleeve <b>104</b>. The polymeric sheath <b>304</b> can cover the entire length of the sleeve <b>104</b> or only a portion or portions of the sleeve <b>104</b>, such as the portions including the plurality of coils <b>108</b> and/or the coiled element <b>202</b> (<b>110</b> and <b>210</b> respectively). The coiled element <b>202</b> can be covered by the same polymeric sheath <b>304</b> as the plurality of coils <b>108</b> or the coiled element <b>202</b> can be covered by a different polymeric sheath <b>304</b>. The coiled element <b>202</b> can also be covered with a polymeric sheath <b>304</b> that has a different color or other different properties than that of the polymeric sheath <b>304</b> that covers the plurality of coils <b>108</b>.

[0051] The polymeric sheath <b>304</b> can reduce the amount of friction between the turns of the plurality of coils <b>108</b> and an inner lining of an anatomical lumen or a catheter used for delivering the medical device <b>300</b>, thereby decreasing the risk of damage to the surrounding area. The polymeric sheath <b>304</b> can be made of silicone, a flouroploymer, such as polytetraflouroethylene (PTFE), expanded polytetraflouroethylene (ePTFE), ethylene-tetrafluoroethylene (ETFE), or other suitable materials that exhibit laser resistant characteristics, e.g., a light color, that prevent or minimize damage to the sleeve <b>104</b> or other elements of the medical device <b>300</b> during a lithotripsy procedure.

[0052] In one embodiment, the color of the polymeric sheath <b>304</b> surrounding the plurality of coils <b>108</b> differs from the color of other portions of the polymeric sheath <b>304</b> and/or from the color of other elements of the medical device <b>300</b> in order to assist a health care practitioner in determining the location of the plurality of coils <b>108</b> within the anatomical lumen during a lithotripsy procedure. In another embodiment, the polymeric sheath <b>304</b> preferably comprises a plurality of colors along a length of the sleeve <b>104</b> to assist the health care practitioner who is performing the lithotripsy procedure to detect movement in the sleeve <b>104</b> and to gauge distances. This enables the health care practitioner to track and maneuver the sleeve <b>104</b> during various phases of the lithotripsy procedure. In one embodiment, the polymeric sheath <b>304</b> exhibits the standard color of a PTFE heat shrunk extrusion with a colored stripe along the length of the sleeve <b>104</b>. As the medical device <b>300</b> is manipulated, the relative size and distances of the wound sections of the plurality of coils <b>108</b> can be readily determined by examining the spiral configuration of the colored stripe, which appears about the wound section of the plurality of coils <b>108</b>. The stripe color is also preferably selected to be resistant to and reflect laser energy so as to minimize damage to the polymeric sheath <b>304</b>.

[0053] In another embodiment, the sleeve <b>104</b> can be covered with a radio-opaque material that enables a health care practitioner to track the medical device <b>300</b> inside a patient under an X-ray machine. In another embodiment, the plurality of coils <b>108</b> are covered with a radio-opaque material, which enables a health care practitioner to track and maneuver the configuration of the sleeve <b>104</b> from a coiled configuration to a substantially linear configuration, as and when needed during a lithotripsy procedure.

[0054]FIG. 4B is a cross-sectional view of the medical device <b>300</b> shown in FIG. 4A. In one embodiment, the medical device <b>300</b> has a generally circular cross-section with a core <b>102</b> disposed in the lumen <b>106</b> of the sleeve <b>104</b> and a polymeric coating <b>304</b> on the external surface <b>302</b> of the sleeve <b>104</b>. In various embodiments, the medical device <b>300</b> can have a cross-section, such as polygonal, arcuate, or combinations of arcuate and polygonal elements.

[0055]FIG. 5A depicts a sleeve <b>104</b> for use with a medical device in accordance with the invention. The sleeve <b>104</b> includes at least one flexible portion <b>404</b> and one or more rigid portions <b>402</b>, <b>406</b>. In the embodiment shown in FIG. 5A, the sleeve <b>104</b> includes a rigid portion <b>402</b>, <b>406</b> on each side of the flexible portion <b>404</b>. The flexibility and rigidity in different portions of the sleeve <b>104</b> can result either from the flexible portion <b>404</b> and more rigid portions <b>402</b>, <b>406</b> having different wall thicknesses (t₁, t₂) or they can be made from different materials that make portions of the sleeve flexible or more rigid. In one embodiment, the flexible portion <b>404</b> can be an expandable balloon. In the embodiment depicted in FIG. 5A, the wall of the flexible portion <b>404</b> has a thickness (t₁) substantially less than the thickness (t₂) of the walls of the rigid portions <b>402</b>, <b>406</b> of the sleeve <b>104</b>. The flexible portion <b>404</b> of the sleeve <b>104</b> changes form from an unexpanded state, i.e., the initial diameter of the sleeve, to an expanded state, i.e., a state of increased diameter. Alternatively, the flexible portion <b>404</b> can be sufficiently pliable to conform to the actual coil shape.

[0056]FIG. 5B depicts a core <b>102</b> for use with a medical device in accordance with the invention. The core <b>102</b> includes a section that is flexible, referred to as a shape-changing section <b>410</b>, and is adapted to change shape when extended through the lumen <b>106</b> of the sleeve <b>104</b>. In one embodiment, the shape-changing section <b>410</b> of the core <b>102</b> has a coiled configuration <b>408</b> when unrestrained. The shape-changing section <b>410</b> of the core <b>102</b> can retain a substantially linear configuration when inserted within the lumen <b>106</b> of the sleeve <b>104</b>. The coiled configuration <b>408</b> of the core can include one coil or a plurality of coils resulting in a shape, such as pigtail, conical, spherical, helical, frusto-conical, or combinations thereof.

[0057] The core <b>102</b> and the sleeve <b>104</b> can be made from the same material or different materials. In one embodiment, the core includes a shape-memory material. In another embodiment, the sleeve includes a shape-memory material. The shape-changing section <b>410</b> of the core <b>102</b> is made from a shape-memory material, which enables reversible change in the shape-changing section <b>410</b> from a coiled configuration <b>408</b> to a substantially linear configuration <b>420</b> (FIG. 5C). The flexible portion <b>404</b> of the sleeve can also be made of a shape-memory material that enables the outer diameter of the flexible portion <b>404</b> to expand when the shape-changing section <b>410</b> of the core <b>102</b> reaches the flexible portion <b>404</b> and forms the coiled configuration <b>408</b>.

[0058]FIG. 5C depicts a medical device <b>400</b> including the elongate sleeve <b>104</b> of FIG. 5A and the elongate core <b>102</b> of FIG. 5B. The core <b>102</b> is inserted into the lumen <b>106</b> of the sleeve <b>104</b> such that the shape-changing section <b>410</b> of the core <b>102</b> is retained in the substantially linear configuration <b>420</b> within the rigid portion <b>402</b> of the sleeve <b>104</b>.

[0059] In the embodiment shown in FIG. 5D, the shape-changing section <b>410</b> of the core <b>102</b> forms a coiled configuration <b>408</b> when the shape-changing section <b>410</b> of the core reaches the flexible portion <b>404</b> of the sleeve <b>104</b>. The outer diameter of the flexible portion <b>404</b> of the sleeve increases to accommodate the coiled configuration <b>408</b> of the core <b>102</b>. The more rigid portions of the sleeve <b>402</b>, <b>406</b> retain the other portions of the core <b>102</b> in a substantially linear configuration. Therefore, the reversible transformation of the shape-changing section <b>410</b> enables the core <b>102</b> to assume a coiled configuration <b>408</b> when the shape-changing section <b>410</b> parallels the flexible portion <b>404</b> and to be retained in the substantially linear configuration <b>420</b> when the shape-changing section <b>410</b> of the core <b>102</b> is retracted from the flexible portion <b>404</b> of the sleeve <b>104</b> to encounter the more rigid portions <b>402</b>, <b>406</b> of the sleeve <b>104</b>. In this manner, the shape-changing section <b>410</b> of the core and the flexible portion <b>404</b> of the sleeve <b>104</b> can change configurations depending on whether the shape-changing section <b>410</b> of the core <b>102</b> is retracted or extended through the section of the lumen <b>106</b> that extends through the flexible portion <b>404</b> of the sleeve <b>104</b>.

[0060] In yet another embodiment and as shown in FIG. 5E, flexible portion <b>404</b> of the sleeve <b>104</b> conforms to the shape of the shape-changing section of the core <b>410</b> when the shape-changing section of the core <b>410</b> reaches the flexible portion <b>404</b> of the sleeve. In this embodiment, the flexible portion <b>404</b> of the sleeve overlays the shape formed by the shape-changing section of the core <b>410</b>, so as to adopt the identical configuration as that of the core <b>102</b>. The flexible portion <b>404</b> of the sleeve <b>104</b> reverts back to a substantially linear configuration when the core <b>102</b> is retracted from within the lumen <b>106</b> of the sleeve.

[0061] A variety of conventional techniques can be used for the manufacture of the sleeve <b>104</b> including flexible and more rigid portions. In one embodiment, the flexible portion <b>404</b> and the more rigid portions <b>402</b> and <b>406</b> of the sleeve <b>104</b> can be manufactured separately and subsequently joined or sealed in an end-to-end or overlapping fashion in order to generate a single sleeve <b>104</b>. The flexible and more rigid portions of the sleeve <b>104</b> can be joined by a number of means known in the art, including heat fusing, adhesive bonding, chemical bonding or mechanical attachment. In one embodiment, the flexible and more rigid portions of the sleeve are hermetically sealed. The flexible portion of the sleeve <b>404</b> can be made from a suitable polymeric material, such as ethylene vinyl acetate, which becomes more pliable upon irradiation.

[0062] FIGS. <b>6</b>A-<b>6</b>C are depictions of another medical device <b>500</b> in accordance with the invention, where both the core <b>102</b> and the sleeve <b>104</b> include shape-changing sections <b>502</b>, <b>504</b> that can form coiled configurations <b>506</b>, <b>508</b>. The sleeve <b>104</b> includes a lumen <b>106</b> that extends within at least a portion of the sleeve <b>104</b> and the core <b>102</b> is slidably disposable within the lumen <b>106</b> of the sleeve <b>104</b>. FIG. 6A is a depiction of the medical device <b>500</b>, where the sleeve <b>104</b> and the core <b>102</b> are unrestrained, e.g., pulled apart from each other, and both shape-changing sections <b>502</b>, <b>504</b> are in their coiled configurations <b>506</b>, <b>508</b>. In this embodiment, the core <b>102</b> is retracted from the lumen <b>106</b> of the sleeve <b>104</b>.

[0063] In FIG. 6B, the shape-changing section <b>504</b> of the sleeve <b>104</b> assumes a substantially linear configuration when restrained, e.g., when a section of the core <b>102</b> other than the shape-changing section <b>502</b> is extended through a section of the lumen <b>106</b> that extends through the shape-changing section <b>504</b> of the sleeve <b>104</b>. Similarly, the shape-changing section <b>502</b> of the core <b>102</b> assumes a substantially linear configuration when restrained, e.g., the core is inserted into a section of the sleeve <b>104</b> other than the shape-changing section <b>504</b>.

[0064] In FIG. 6C, the shape-changing sections <b>502</b>, <b>504</b> are aligned such that both assume their coiled configurations <b>506</b>, <b>508</b>. In one embodiment, the shape-changing sections <b>502</b>, <b>504</b> can include a plurality of coils configured in a shape, such as conical, spherical, helical, frusto-conical, or combinations thereof. In one embodiment, the shape-changing sections <b>502</b>, <b>504</b> are adapted to assume at least partially their coiled configurations <b>506</b>, <b>508</b> when only partially aligned. Alternatively, the shape-changing sections <b>502</b>, <b>504</b> can be adapted to retain their substantially linear configuration <b>510</b>, <b>512</b> when only partially misaligned. In one embodiment, the coil configurations of the sleeve section and the core section are equal in size and shape. For example, the sleeve section coil configuration can include eight coils in a conical shape and the core section coil configuration can include eight coils in a complimentary conical shape.

[0065] FIGS. <b>7</b>A-<b>7</b>C depict examples of different coil shapes that may be formed in the core <b>102</b>, the sleeve <b>104</b>, or both. FIG. 7A is a depiction of a spherical shape <b>604</b> formed by the plurality of coils. FIG. 7B is a depiction of a helical shape <b>606</b> formed by the plurality of coils. In FIG. 7C, the shape is a single coil in a pigtail configuration, instead of a plurality of coils, as shown in FIGS. 7A and 7B. The shape and size of the coil configuration is selected based on the intended use of the medical device.

[0066] In all the foregoing aspects of the invention, the overall length of the medical device depends on the application for which the medical device is intended. Generally, the overall length will be in the range of about 50 cm to about 250 cm. In one embodiment and with respect to urinary applications, the total length of the device <b>100</b> is about 140 cm to about 220 cm, and preferably about 200 cm. Devices for other applications, or those intended for use with children, will be different lengths.

[0067] The diameters of the sleeve <b>104</b> and the core <b>102</b> depend on the application for which the device is intended. For example, in the case of urinary applications, the maximum outside diameter of the sleeve <b>104</b> is typically in the range of about 0.5 mm to about 1.5 mm and the maximum diameter of the core <b>102</b> is such as to enable the core <b>102</b> to be slidably disposed within the lumen <b>106</b> of the sleeve <b>104</b>. For other applications, for example, use of the device for the removal of an obstruction in the gastrointestinal tract, the outside diameter of the sleeve <b>104</b> can be as large as about 1 cm to about 2 cm.

[0068] In all the forgoing aspects of the medical device of the invention, the number of coils in plurality of coils of the sleeve and the core depends on the intended use of the medical device. In one embodiment, the plurality of coils has between about 5 turns and about 15 turns, and preferably about 7 turns to about 10 turns. The maximum outside diameter of the proximal end of the plurality of coils can be, for example, in the range of about 0.2 cm to about 3.0 cm, and preferably about 0.7 cm to about 0.8 cm. Adjacent turns of the plurality of coils may abut each other or be separated by small gaps <b>122</b>. In the embodiment shown in FIG. 1A, the gaps <b>122</b> are up to about 2 mm wide; however, the gaps can be varied to suit a particular application.

[0069] The location of the plurality of coils also depends on the intended use of the medical device. In one embodiment, the distance <b>116</b> of the coils from the proximal end of the device is about 0.0 cm to about 15.0 cm. In another embodiment, the distance <b>116</b> can be about 50 cm to about 200 cm, or about 100 cm to about 130 cm and preferably about 120 cm to about 130 cm.

[0070] In all the forgoing aspects of the medical device of the invention, the sleeve <b>104</b> and core <b>102</b> can be manufactured by, for example, injection molding or extrusion and optionally a combination of subsequent machining operations. Extrusion processes may be used to provide a uniform shape, such as a single monolithic frame. Injection molding can then be used to provide the desired geometry of the open spaces, or the open spaces could be created in the desired locations by a subsequent machining operation. In one embodiment, the sleeve <b>104</b>, the core <b>102</b>, or both can be made from a co-extrusion high density polyethylene for an inner portion and a polyamide for the outer portion. The co-extrusion process results in the necessary combination of flexibility, to navigate tortuous vessels, and column strength to effectively straighten out the coil. In addition, the coextrusion process can be used to produce the sleeve <b>104</b> and polymeric coating <b>304</b>. Alternatively, the core <b>102</b> could be drawn wire.

[0071] In all the foregoing aspects of the invention, the shapes of the sleeve and the core can be generated by wrapping the desired portions of the sleeve or the core around a mandrel to form into the desired shape and then heating at sufficient time and temperature to set the shape into the sleeve, the core, or both. The time or the temperature largely depends on the type of material that is used for the manufacture of the sleeve and the core. Once the portions of the sleeve or the core have been heat-treated to set into the desired configurations, the sleeve or the core may be straightened by pulling at the linear portions on either side of the shape; however, the sleeve and the core will return to the wound configurations when released.

[0072] Other embodiments incorporating the concepts disclosed herein are within the spirit and scope of the invention. The described embodiments are illustrative of the invention and not restrictive.