Endoscopic stone extraction device with rotatable basket

[0002] The present invention relates to basket-type devices for extracting stones such as ureteral stones, calaceal stones and other calculus and the like from the renal or biliary systems.

[0003] Various types of stone extraction baskets have been used in the past to extract stones and stone fragments from various biological systems. See for example the devices shown in the following U.S. Patents: Bates U.S. Pat. No. 6,099,534, Okada U.S. Pat. No. 6,093,196, Ouchi U.S. Pat. No. 6,077,274, Bilitz U.S. Pat. No. 6,059,796, Foster U.S. Pat. No. 5,989,266, Bates U.S. Pat. No. 5,957,932, Bates U.S. Pat. No. 5,788,710, Bates U.S. Pat. No. 5,496,330, Dormia U.S. Pat. No. 4,612,931, and Segura U.S. Pat. No. 4,590,938.

[0004] A typical stone extraction basket includes a wire basket carried by one end of a wire that is received within the lumen of a sheath. The end of the wire opposite the basket is secured to a handle that is used to slide the sheath over the wire, thereby moving the basket into and out of the lumen of the sheath. When the basket is out of the sheath, it expands to receive a stone. The sheath is then moved toward the basket to reduce the size of the basket openings, and the basket and the enclosed stone are removed from the body.

[0005] Recently, ultrasonic, laser, and electro-hydraulic techniques have been used to fragment stones in situ. Typically, the stone fragments are left in the body to be excreted. However, in some cases stone fragments may not be excreted as quickly or as completely as desired. Conventional stone extraction baskets are not optimized for the extraction of shattered stone fragments. Thus, a need presently exists for an improved endoscopic stone extraction device that is easier to use and better suited for the extraction of stone fragments.

[0006] The preferred embodiments described below include a new type of handle that permits the stone extraction basket to be rotated easily by the user and a new type of stone extraction basket that is well suited to the collection of small stone fragments.

[0007] The handle described below allows the basket to be rotated inside the body, as for example to orient the basket to admit a stone into the basket. The improved basket designs described below facilitate the retention and extraction of small stone fragments.

[0008] In one embodiment, the stone extraction basket has a large, side-facing opening to admit stones and stone fragments into the interior of the basket, and over half of the surface area of the basket is provided with relatively small openings adapted to retain stones and stone fragments in the basket. In another embodiment, the large openings of the basket are oriented to face the sheath, and the stone retention portion of the basket is disposed opposite the sheath.

[0009] The foregoing section has been provided by way of general introduction, and it should not be used to narrow the scope of the following claims.

[0010] FIG. 1 is a perspective view of an endoscopic stone extraction device that incorporates a preferred embodiment of this invention.

[0011] FIG. 2 is a cross-sectional view taken along line 2—2 of FIG. 1.

[0012] FIGS. 3, 4 and 5 are detailed views of a thumb wheel included in the embodiment of FIGS. 1 and 2.

[0013] FIG. 6 is an exploded perspective view of a portion of the handle and the end portion of the wire of the embodiment of FIGS. 1 and 2.

[0014] FIG. 6ais an exploded perspective view of the elements 73, 74 of FIG. 6 from another viewing angle.

[0015] FIG. 7 is a cross-sectional view corresponding to that of FIG. 2 of a second preferred embodiment of this invention.

[0016] FIG. 8 is a fragmentary side view of selected elements of the embodiment of FIG. 7.

[0017] FIGS. 9, 10 and 11 are enlarged perspective views of three stone retention baskets suitable for use in the embodiments of FIGS. 1-8.

[0018] Turning now to the drawings, FIG. 1 shows an endoscopic stone extraction device 10 that incorporates a preferred embodiment of this invention. The device 10 includes a handle 12 that in turn includes a grip 14 and a slide 16. As explained in greater detail below, the slide 16 is mounted to slide longitudinally along the length of the grip 14.

[0019] A tubular sheath 18 is secured to the slide 16. The sheath 18 defines a lumen 19, and the sheath 18 can be formed of any suitable flexible material, including the materials described in the above-identified prior-art patents. A strain relief collar 20 is provided at the point where the sheath 18 is secured to the slide 16 to reduce the incidence of kinking.

[0020] The device also includes a filament 22 having a first end 24 (FIG. 2) and a second end 26 (FIG. 1). The first end 24 is rotatably secured to the grip 14 (FIG. 2), and the second end 26 supports a stone extraction basket. The filament 22 can be formed of any suitable material, and is typically formed of a flexible metallic wire. Preferably, the first end 24 is thicker and stiffer than the second end 26 to facilitate insertion and manipulation of the basket 28.

[0021] The following sections will first describe the handle 12 in greater detail, before turning to alternative forms of the basket 28.

[0022] The Handle 12

[0023] As best shown in FIG. 2, the handle 12 includes a tube 30 that defines a longitudinally extending slot 32. The tube 30 forms a bore 34 and terminates at one end in external threads 36. Protruding elements 38 extend away from the perimeter of the tube 30 to facilitate the grasping of the tube 30 by a physician during use. For purposes of discussion, the portion of the tube 30 adjacent the external threads 36 will be referred to as the rear portion 42, and the opposite end of the tube 30 will be referred as the front portion 40. The tube 30 may for example be formed of any suitable, moldable thermoplastic material, though the widest variety of materials can be adapted for use with this invention.

[0024] Continuing with FIG. 2, the slide 16 includes a guide cylinder 50 sized to slide along the bore 34 of the tube 30. This guide cylinder 50 defines a central opening 52 sized to pass the filament 22 with little or no friction therebetween. The slide 16 also includes an arm 54 that extends from the guide cylinder 50 through the slot 32 to a plate 56. The arm 54 holds the plate 56 in alignment with the centerline of the tube 30. The slide 16 includes a gripping portion 58 that can be pushed or pulled by a physician during use to move the slide 16 along the longitudinal axis of the tube 30. As before, a wide range of materials can be used for the slide 16, including any suitable thermoplastic material.

[0025] As shown in FIGS. 1-5, a disk 60 is provided. This disk 60 is positioned adjacent the front portion 40 of the tube 30. The disk 60 is clamped onto the filament 22, and the disk 60 is rotatable with respect to both the tube 30 and the slide 16. As shown in FIGS. 3-5, the disk 60 includes half-disks 66, 68 that snap together in a releasable manner. The half-disks 66, 68 carry respective elastomeric gripping portions 69 designed to grip the filament 22 therebetween when the half-disks 66, 67 are snapped together.

[0026] As best shown in FIGS. 1, 2, 6 and 6a, the handle 12 carries a threaded cap 70 that defines a set of internal threads sized to mate with the external threads 36. The cap 70 includes a socket 71 that bears on a chuck 72. When the cap 70 is tightened in place, the chuck 72 is held between the socket 71 and an internal socket 31 formed by the tube 30. The chuck 72 is free to rotate but not to translate with respect to the tube 30.

[0027] The chuck 72 includes two parts 73, each having a central groove 77 sized to clamp against the filament 22. The groove 77 may be lined with an elastometric layer to ensure good frictional contact between the chuck 72 and the filament 22. Each part 73 defines external threads, and the parts 73 are clamped against the filament by a cap nut 74 such that the chuck 72 rotates and translates in unison with the filament 22. The chuck 72 forms a convex surface 75 that engages the socket 31, and a convex surface 76 that engages the socket 71. The surfaces 75, 76 are shaped to allow low-friction rotation of the chuck 72 and the filament 22 relative to the tube 30. Thus, the chuck 72 and associated elements carried by the tube 30 form a rotational joint.

[0028] Other types of rotational joints may be used, including ball-and-socket joints. For example, a ball-and-socket joint may be included in the filament 22 near the first end 24, and the first end 24 may be fixed to the tube 30. Also, the filament may have an enlarged end that forms part of the rotational joint, and the enlarged end may be sized to fit through the lumen of the sheath 18. Alternatively, the enlarged end may be too large to fit through the lumen of the sheath, and may be removable from the body of the filament 22, e.g. by disassembling the enlarged end from the filament 22.

[0029] In use, the device 10 is assembled as shown in FIGS. 1 and 2. Initially, the slide 16 is advanced (i.e. moved to the right in the view of FIG. 2) to move the sheath 18 over the basket 28. This reduces the cross-sectional dimensions of the basket 28 and facilitates insertion of the basket 28 into a region of the body adjacent to the stone to be removed. The slide 16 is then moved to the left in the view of FIG. 2 to expose the basket 28, which resiliently assumes an enlarged operational shape. As described in greater detail in the following section relating to the basket, the basket defines one or more large, stone-receiving openings, and in some embodiments the stone-receiving openings are laterally facing. The physician can position the basket as desired by manipulating the disk 60, thereby rotating the filament 22 and the attached basket 28.

[0030] It should be apparent from the foregoing discussion that rotation of the disk 60 and the filament 22 occurs without rotation of the sheath 18, the slide 16 or the handle 12. This arrangement facilitates rotation of the filament 22 and the basket 28 inside the lumen of the body cavity in which it is inserted, since friction between the sheath 18 and the endoscopic device and between the sheath 18 and adjacent tissue do not impede rotation of the filament 22 and the basket 28. Rotation of the filament 22 is guided by the rotational joint that includes the chuck 72. Once a stone has been captured within the basket, the slide 16 is then moved to the right in the view of FIG. 2 to move the sheath over at least a portion of the basket, thereby securely capturing the stone in the basket for removal.

[0031] On occasion, it may be necessary to remove the handle 12, the slide 16 and the sheath 18 while leaving the filament 22 and the basket 28 in place. This can readily be accomplished by unscrewing the cap 70 from the handle 12, removing the cap nut 74 from the parts 73, and then removing the parts 73, handle 12, slide 16 and sheath 18 from the filament 22.

[0032] The disk 60 is an example of a manipulator used to rotate the filament 22 relative to the handle 12. This manipulator can take other forms, including the form shown in FIGS. 7 and 8. The embodiment of FIGS. 7 and 8 is similar to that of FIGS. 1 and 2, except that the disk 60 has been replaced by a lever 80. This lever 80 defines a free end 82 and hinged end 84, and the free end 82 is positioned closer to the first end 24 of the filament 22 than is the hinged end 84. During normal use, the lever 80 is positioned as shown in FIG. 7 in an extended position. In this position the user can apply torques to the lever 80 and therefore to the filament 22 to rotate the filament 22 as described above. The hinged end 84 is connected to the filament 22 at a hinged joint (e.g. a living hinge or a multiple-part hinge) and the lever 80 can be moved to the retracted position shown in dotted lines in FIG. 8. In this retracted position, the lever 80 can be moved through the lumen of the sheath 18, thereby allowing the handle, slide and sheath to be removed from the filament 22 as described above.

[0033] The Stone Extraction Basket 28

[0034] The handle 10 described above can be used with any desired stone extraction basket, and also in the ureter when appropriate. However, the preferred stone extraction baskets are formed as shown in FIGS. 9, 10 and 11.

[0035] The stone extraction basket 28 of FIG. 9 is well adapted for use as a calaceal stone extraction basket. This basket includes a stone entrance region 100 and a stone retention region 102. The retention region 102 extends over more than half the area of the basket. This basket is formed by a set of longitudinal basket wires 104 and a set of lateral basket wires 106. The longitudinal basket wires 104 form a larger opening 108 in the stone entrance region 100, and the basket wires 104, 106 cooperate to form a number of smaller openings 110 in the stone retention region 102. In this embodiment, the larger opening 108 is sized to admit a stone that is at least two millimeters in diameter, and the smaller openings 110 are sized to retain a stone smaller than two millimeters in diameter. In one example, the larger opening is sized to admit stones as large as 5 mm in diameter. The wires 104, 106 are preferably small, flexible, kink-resistant wires that are capable of collapsing together to fit within the lumen 19.

[0036] In FIG. 9 the basket is shown in its operational configuration in which the basket is fully outside of the lumen 19 of the sheath 18. As described above, after a stone has been captured within the basket of FIG. 9, the sheath 18 can be moved over part of the basket 28 to reduce the size of the larger opening 108.

[0037] The basket 28 can also be used to capture ureteral stone fragments. In one example, the basket is inserted into a tract (such as the urinary tract or the biliary tract) with an endoscope, and the basket is positioned around a stone to be fragmented. Then the stone is fragmented, for example with a laser or an electro-hydraulic stone fragmenting device. On some occasions, the initial stone fragmentation operation will leave stone fragments that are too large for extraction. In this case, the surgeon can rotate basket and the partially-fragmented stone to align one of the larger stone fragments with the fragmenting device (e.g. the laser) and then repeat the stone fragmentation operation. In this way, selected stone fragments can be aligned with the stone fragmentation device as necessary to reduce the largest stone fragments to the desired size. Any suitable basket, including all of the baskets described herein, can be used to practice this method.

[0038] It should be noted that the larger opening 108 faces laterally with respect to a longitudinal basket axis extending through the second end 26 of the filament 22. Because the larger opening 108 is laterally facing, the filament rotating features of the handle 12 described above can be used to orient the larger opening 108 as desired to facilitate stone capture. Also, in the event a stone is captured that is too large to be removed from the body, the basket can be rotated to point the larger opening 108 downwardly. In this orientation, the weight of the stone tends to move it out of the basket. Once this occurs, the basket can be removed from the body and the stone fragmented using conventional lithothripsy techniques.

[0039] The basket 28′ of FIG. 10 is similar to the basket 28 of FIG. 9 except that the stone entrance region 100′ is positioned adjacent the second end 26 of the filament 22, and the stone retention region 102′ is positioned opposite the second end 26 of the filament 22. The basket 28′ is well suited for the collection of ureteral stone fragments after laser, ultrasonic, or electro-hydraulic lithothripsy. Also, the basket 28′ may be positioned proximally of a stone prior to lithothripsy to prevent stone fragments from migrating up the ureter. In use, the collapsed basket 28′ is moved past the stone or stones to be collected, then the sheath 18 is moved to allow the basket 28′ to expand to the operational configuration of FIG. 10, and then the basket 28′ is moved to collect the stones in the stone retention region. At this point, the sheath 18 is moved over the filament 22 to collapse the basket 28′ partially, thereby retaining the captured stones in the stone retention region 102′.

[0040] FIG. 11 shows a basket 28″ that is similar to the basket 28 of FIG. 9, including a stone entrance region 100″ and a stone retention region 102″. The main difference is that the basket 28″ is shaped differently as appropriate for use as a percutaneous stone extraction basket.

[0041] The wires 104, 106 may be formed continuously with the filament 22, or alternately they may be secured to the filament 22. A variety of materials can be used for the wires 104, 106, but they should be sufficiently small in diameter, flexible and kink-resistant to allow the baskets 28, 28′, 28″ to be collapsed into the lumen 19. Super-elastic alloys such as the shape memory metal alloys described in U.S. Pat. No. 5,989,266 are suitable. One such shape-memory material is nitinol, which can be annealed as described in this patent. Other materials known to those skilled in the art can readily be used to form the baskets 28, 28′, 28″. The junction between adjacent wires in the baskets 28, 28′, 28″ can be secured in any suitable way, including sutures, adhesives, and knots of the type described in U.S. Pat. No. 5,989,266.

[0042] The number of longitudinal basket wires 104 can be varied with the application, and 2, 3, 4, 5, 6 or more longitudinal wires can be used.

[0043] For the reasons discussed above, it is preferred to use the baskets 28, 28′, 28″ with the handle 12 of FIGS. 1 and 2. However, it should be clearly understood that the baskets of this invention are not limited to use with any particular handle, and a wide variety of handles can be used.

[0044] Conclusion

[0045] It should be apparent from the foregoing detailed description that improved endoscopic stone extraction devices have been described that are well suited to the collection of a wide variety of stones, including stone fragments. The stone extraction devices described above can be used with the widest variety of endoscopes, including ureteroscopes, nephroscopes and other endoscopic devices. Urinary tract stones and biliary tract stones are two examples.

[0046] As used herein, the term “stone” is intended broadly to encompass a wide variety of biological stones, calculus and the like, including fragments of stones, calculus and the like formed by any of the techniques described above or other techniques developed in the future.

[0047] The term “end portion” is intended broadly to encompass the end of structure such as a filament along with an adjacent portion of the structure.

[0048] The term “surface” is intended broadly to encompass perforated surfaces.

[0049] The foregoing detailed description has discussed only a few of the many forms that this invention can take. For this reason, this detailed description is intended by way of illustration and not limitation. It only the following claims, including all equivalents, that are intended to define the scope of this invention.