Endoscopic suture clip

Abstract: A method of clamping suture strand (24) by applying heat and compressive force to a polymeric surgical clip (10) having first (11) and second (12) opposed leg members so as to clamp the suture strand (24) between the opposed inner clamping surfaces (14,15) of the first (11) and second (12) leg members; a surgical clip (10) defined by first (11) and second (12) leg members, the first leg member (11) having a hole (20) therein; and a surgical device (30) for clamping a clip (10) about a suture (24), such device (30) defined by a trigger-activated handle (31), clamping jaws (32) with a heating element (23) disposed on one of the clamping members (33,34) of the clamping jaws (32), a shaft (35) connecting the jaws (32) to the handle (31), and means (37-39) for activating the heating element (23) and for delivering compressive force to the clamping jaws (32) to close the clip (10) about a suture (24).

Description: BACKGROUND OF THE INVENTION This invention relates generally to a surgical clip. More particularly, it relates to such a clip suitably adapted to replace a suture knot during endoscopic surgery, as well as a method of applying such a clip to clamp a suture, and a device for accomplishing this method. As medical and hospital costs continue to increase, surgeons are constantly striving to develop advanced surgical techniques. Advances in the surgical field are often related to the development of operative techniques which involve less invasive surgical procedures and reduce overall patient trauma. In this manner, the length of hospital stays can be significantly reduced, and therefore the hospital and medical costs can be reduced as well. One of the truly great advances in recent years to reduce the invasiveness of surgical procedures is endoscopic surgery. Endoscopic surgery involves the use of an endoscope, which is an instrument permitting the visual inspection and magnification of any cavity of the body. The endoscope is inserted through a cannula after puncture through the wall of the body cavity with a trocar, which is a sharp-pointed instrument. The surgeon can then perform diagnostic and therapeutic procedures at the surgical site with the aid of specialized instrumentation designed to fit through additional cannulas providing small diameter openings into the desired body cavity as may be required. An age-old procedure which surgeons are required to perform to repair or reconstruct traumatized bodily tissue is suturing. Fortunately, medical instruments have been recently designed to allow a surgeon to manipulate a suture, or suture and needle combination, through the small diameter opening of a cannula. However, the ability to tie an appropriately placed suture knot has become troublesome and problematical. Therefore, in response to this problem, surgeons have sought alternatives to conventional knot-tying techniques which would be suitable during endoscopic surgery. Among these alternatives include the use of hemostatic clips, which are designed to ligate blood vessels and other tubular members, to replace suture knots. Such hemostatic clips are described, for example, in U.S. Patent Nos. 4,418,694 and 4,476,865. These clips can be readily applied with a clip applier which is designed to function through the small opening of a cannula. Unfortunately, the force required to displace these clips from the suture is inadequately low. As a result, hemostatic clips of the type shown in the art are unsuitable for general endoscopic surgery needs. More recently, attempts have been made specifically to replace tying suture knots. U.S. Patent 4,662,068 describes an apparatus which performs the multiple functions of fusing adjacent suture strands together as well as cutting the strands after the fusing operation is performed. Unfortunately, such a device is unable to transmit to the adjacent suture strands an adequate adhesive force to prevent the suture strands from disengaging. U.S. Patent 4,078,731 describes a suture clip which eliminates the need for tying suture knots. The clip configured in such a manner which allows the clip to be manipulated into a first position which defines a complete passageway around the suture being threaded through the clip. Once the clip is placed adjacent to desired bodily tissue, the clip is manipulated into a second position for clamping the suture. Although this clip can be designed to achieve adequate clamping force, unfortunately the overall design of the clip requires delicate fabrication which can lead to practical difficulties. US patent 3,856,016 discloses an occlusion clip requiring less delicate fabrication that clamps over a anatomical tubular structure, squeezing the tubular structure into a flat shape therefore sealing the tubular structure shut. In view of the deficiencies of the prior art for creating a useful alternative to tying a suture knot, what is desired within the medical community is a clip and a method for applying the clip using endoscopic techniques which can successfully replace the suture knot. In addition it would be helpful if a suitable clip applier were developed which could be used in conjunction with such a clip and the method for applying the clip. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described in greater detail in conjunction with the accompanying drawings wherein: Figure 1 is a perspective view of the surgical clip of the present invention. Figure 2 is a perspective view of the surgical clip and a suture strand prior to clamping the suture strands. Figure 3 is a perspective view of the clip of Figure 2 after the clip is clamped about the suture strand. Figure 4 is a side elevational view of a device that can be used for applying the clip. Figure 5 is an enlarged detail view of a plurality of clips of this invention used in conjunction with a device for applying multiple clips. Figure 6 is a perspective view which illustrates another embodiment for using the method of this invention with a conventional clip to attach adjacent suture strands. SUMMARY OF THE INVENTION In one aspect, the invention is a method of securely applying a surgical clip to a strand of suture. The method comprises the steps of a) providing a surgical clip composed of a polymeric material with first and second leg members joined at their proximal ends, each leg member having a clamping inner surface, said clamping inner surface being in opposition to the clamping inner surface of the other leg member; b) placing the strand of suture between the clamping inner surfaces of the first and second leg members; characterised in that the polymeric material has a low softening temperature; heat is applied to at least a portion of the clip so as to soften the polymeric material from which the clip is composed; and a compressive force is applied against the first and second leg members of the clip while the clip is in a softened state so as to clamp the strand of suture between the clamping inner surfaces of the first and second leg members; and then the heat and compressive force is removed from the clip. In another aspect, the invention is a surgical clip. The surgical clip comprises first and second leg members. Each leg has an outer grasping surface, a clamping inner surface, and an outer distal surface connecting the outer grasping to the clamping inner surface. The clamping inner surface of each leg member is in opposition to the clamping inner surface of the other leg member. In addition, the first leg member has a hole therein. The clip is characterised in that the clip is composed of a polymeric material with a low softening temperature. In a further aspect of the invention, the invention is a combination of a surgical device for clamping a surgical clip about a suture and the clip, in which the clip is composed of a polymeric material with first and second opposed leg members as described in Claim 21. The method of this invention provides a unique way of using a simple clip design to securely anchor or fasten a strand of suture with an adequate clamping force and adhesive power to prevent the suture strand from disengaging. Surprisingly, the clamping and adhesive forces are adequate to eliminate the need for tying suture knots. Advantageously, the method of this invention is used in conjunction with endoscopic surgery, and therefore represents a tremendous advance in the state of the medical art by eliminating the need for tying suture knots. A surgical clip of the invention is simple in design, easy to fabricate, and can be used with a vast array of surgical devices for applying the clip. The device of this invention for applying the clip can be especially adapted for use during endoscopic procedures which require the manipulation and placement of the clip within the body cavity through a trocar. The invention as described herein can be utilized in any surgical procedure which requires suturing, and therefore requires the fastening or anchoring of a suture strand. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figure 1, there is shown a surgical clip 10 of the present invention. The surgical clip has a first leg member 11 and a second leg member 12 which join together at their proximal ends at outer proximal surface 13. The first leg member has a clamping inner surface 14, an outer grasping surface 16, and an outer distal surface 18 which facially connects the clamping inner surface to the outer grasping surface. Correspondingly, the second leg member has a clamping inner surface 15, an outer grasping surface 17, and an outer distal surface 19 which connects the outer grasping surface to the clamping inner surface. The clamping inner surface of the first leg member is a substantially flat surface, while the opposed clamping inner surface of the second leg member has a major surface 21 which is substantially flat and a ridge 22 formed on this major surface. The ridge extends longitudinally from the outer distal surface of the second leg member in a direction substantially parallel to the axis of the second leg member. The ridge facilitates the clamping force which is placed upon a suture strand when the strand is clamped within the clip. The clip has a hole 20 extending therethrough for facilitating the application of heat internally to the clip to allow the material from which the clip is composed to achieve a softened state for clamping. Alternatively, the hole can be used to allow placement of the clip on the shaft of a clip applier, while heat is applied to another portion of the clip from a source located on the clamping jaws of the clip applier. The hole is advantageously disposed within the first leg member between the outer grasping surface and the clamping inner surface. The hole is desirably cylindrical for ease of fabrication, and extends completely through the first leg member from the outer distal surface 18 to the outer proximal surface 13. For ease of manipulation of the clip when a heating element is inserted into the hole, the hole is advantageously disposed in a direction which is substantially parallel to the axis of the first leg member. The surgical clip of this invention can be made of any polymeric material which is biocompatible with bodily tissue and bioabsorbable. The preferred bioabsorbable polymeric materials are homopolymers and copolymers of glycolide, lactide, para-dioxanone, trimethylene carbonate and ε-caprolactone. The preferred polymer material is derived from the polymerization of para-dioxanone, because of the low softening temperature of polymers derived from para-dioxanone. The preferred means for fabricating the clip from bioabsorbable polymeric materials is to inject a suitable polymer melt into an appropriately designed mold at process conditions conventionally employed for such polymer systems. After the polymer melt cools in the mold, polymer shaped in the proper configuration to meet the design criteria of the clip is released from the mold. The molded clip can then be sterilized using conventional methods to render the clip suitable for surgical applications. Referring now to Figures 2 and 3, there is shown the process by which the clip of this invention can be clamped about a strand of suture, thus eliminating the need to tie a surgical knot during surgery. A heating element 23 can be extended through the first leg member of the clip. Once the heating element is extended through the clip, and the clip is ready to be softened, the suture strand which is desired to be clamped is placed between the clamping inner surfaces of the leg members of the clip. When the suture strand is properly positioned between the opposed inner surfaces, the heating element can be activated so that heat generated from the heating element raises the temperature of the polymeric material from which the clip is composed until such temperature exceeds the softening temperature of the polymeric material. This temperature is most often achieved when the temperature of the polymer exceeds its glass transition temperature. When the proper softening temperature is reached, compressive force can be applied to the opposed leg members as shown by the direction of the arrows at Figure 3, so that the suture strand becomes securely clamped between the clamping inner surfaces of the leg members of the clip. When the clamping operation is completed, the heat and the compressive force can then be removed. Advantageously, this method can be used to fasten or anchor not only one strand of suture but also two or more adjacent strands of suture. This can be accomplished because of the high pull force required to disengage the clamped strands due to the combination of clamping and adhesive action of the clip. The method of the invention is advantageously carried out over a very short period of time, preferably within less than 10 seconds. This can be accomplished by applying a short burst of heat energy to the leg member, while simultaneously applying compressive force to the leg members to clamp the suture within the inner surfaces of the clip. Although this would be the preferred means for carrying out the invention, it is certainly not a limiting factor in how the method of the invention can be carried out. An alternative embodiment of the invention is illustrated at Figure 5. A shaft of a device for grasping a clip and applying compressive force is designed to carry a plurality of clips on the shaft for proper placement within the body. A heating element can be placed on the longitudinal shaft at its distal tip or alternatively, on the grasping member of the device. Heat is then applied to at least a portion of the most distally disposed clip on the shaft to soften the clip, and the softened clip is pushed distally from the shaft to fully engage the grasping member of the device. The grasping member of the device can then be activated to apply compressive force on the clip for clamping about a suture. In turn, the remaining clips would be pushed distally along the shaft for continuing application of multiple clips. Figure 6 illustrates that it is unnecessary to utilize a clip having a hole extending through one of its leg members to practice the method of this invention. It is entirely possible to use a heating element which can be attached or contacted in some fashion to any clip having two opposed leg members, provided at least a portion of such a clip can be heated to a temperature above its softening temperature for subsequent application of compressive force on the leg members for clamping. Figure 4 shows a surgical device 30 of this invention for clamping surgical clip 10. The device as shown can be utilized with the alternative embodiment depicted in Figure 5 for the application of multiple clips. The device includes a trigger-activated handle 31 having a base 36 and an actuating trigger 37. The trigger can be squeezed against the base when the user applies force in the direction of the arrow as shown. After the application of such force, the trigger returns to its position shown in Figure 4. In addition to the handle, there is a longitudinal tubular shaft 30 which connects the handle to clamping jaws 32. The longitudinal shaft has a long neck which is suitably configured to be placed down a trocar sleeve during endoscopic surgery. The clamping jaws have first and second opposed clamping members, shown at 33 and 34 respectively, configured to grasp the first and second opposed leg members of a clip. The first clamping leg member has a heating element 32 disposed thereon for applying heat to the most distally-positioned clip. Alternatively, the heating element could be disposed at the distal end of the shaft, where it can extend through the hole of the most distally-positioned clip. To use the surgical instrument shown in Figure 4, the user would squeeze the trigger against the base of the handle to activate contact switch 38, which in turn would power a suitable power source 39. This power source may be a low voltage battery which also may be rechargeable. Once the battery is turned on, the heating element is activated and the clip is softened while grasped within the clamping jaws of the instrument. Simultaneously with this action, the squeezing of the trigger causes the shaft to rotate in the direction of the arrow as shown to allow the clamping jaws of the instrument to apply compressive force against the leg members of the clip for clamping the clip about a suture. While this invention has been described in its most preferred embodiments, there are a vast array of additional embodiments which would fall within the scope of the claimed invention as defined by the appended claims, and such additional embodiments should not be construed to fall outside the scope of the appended claims merely because they have not been specifically described herein.

Claims: A method of securely applying a surgical clip to a strand of suture (24) comprising the steps of: a) providing a surgical clip (10) composed of polymeric material with first and second leg members (11 and 12) joined at their proximal ends, each leg member having a clamping inner surface (14 and 15), said clamping inner surface (14) being in opposition to the clamping inner surface (15) of the other leg member; b) placing said strand of suture (24) between the clamping inner surfaces (14 and 15) of said first and second leg members (11 and 12); characterised in that the polymeric material has a low softening temperature; heat is applied to at least a portion of said clip (10) so as to soften said polymeric material from which said clip (10) is composed; and a compressive force is applied against said first and second leg members (11 and 12) of said clip (10) while said clip (10) is in a softened state so as to clamp said strand of suture (24) between said clamping inner surfaces (14 and 15) of said first and second leg members (11 and 12); and said heat and said compressive force is removed from said clip (10). The method of Claim 1 wherein the steps of applying heat and compressive force are performed simultaneously. The method of Claim 1 wherein the clip (10) has means for receiving the application of heat internally within said first leg member. The method of Claim 3 wherein the first leg member (11) has a hole (20) therein for receiving the application of heat internally. The method of Claim 4 wherein each leg member (11 and 12) of said clip (10) has an outer grasping surface (16 and 17) and an outer distal surface (18 and 19), said outer distal surfaces (18 and 19) connecting said outer grasping outer surfaces (16 and 17) to said clamping inner surfaces (14 and 15). The method of Claim 5 wherein said hole (20) is disposed between said outer grasping surface (16) and said clamping inner surface (14) of said first leg member (11). The method of Claim 6 wherein said first and second leg members (11 and 12 ) are joined at their proximal ends by an outer proximal surface (13). The method of Claim 7 wherein said hole (20) is a cylindrical hole (20) extending from said outer distal surface (18) to said outer proximal surface (13). The method of Claim 8 wherein said cylindrical hole (20) is disposed in a direction substantially parallel to the axis of said first leg member (11). The method of Claim 9 wherein said clip (10) is composed of a polymeric material which is bioabsorbable. A surgical clip (10) comprising first and second leg members (11 and 12), each leg member having an outer grasping surface (16 and 17) a clamping inner surface (14 and 15), and an outer distal surface (18 and 19) connecting said outer grasping surfaces (16 and 17) to said clamping inner surfaces (14 and 15) said clamping inner surfaces (14 and 15) being in opposition to the clamping inner surface of the other leg member, said first leg member (11) having a hole (20) therein; characterised in that the surgical clip (10) is composed of a polymeric material with a low softening temperature. The clip (10) of Claim 11 wherein said first and second leg members (11 and 12) are joined together at their proximal ends by an outer proximal surface (13). The clip (10) of Claim 12 wherein said hole (20) is disposed between said outer grasping surface (16) and said clamping inner surface (14) of said first leg member (11). The clip (10) of Claim 13 wherein said hole (20) is a cylindrical hole (20) extending from said outer distal surface (18) to said outer proximal surface (13). The clip of Claim 14 wherein said cylindrical hole (20) is disposed in a direction substantially parallel to the axis of said first leg member (11). The clip (10) of Claim 15 wherein said clamping inner surface (14) of said first leg member (11) is a substantially flat surface. The clip (10) of Claim 16 wherein said clamping inner surface (14) of said second leg member (12) has a major surface (21) which is substantially a flat surface. The clip (10) of Claim 17 wherein said major surface (21) of said clamping inner surface (15) of said second leg member (12) has a ridge (22) formed thereon. The clip (10) of Claim 18 wherein said ridge (22) extends from said outer distal surface (19) in direction substantially parallel to the axis of said second leg member (12). The clip (10) of Claim 19 wherein said polymeric material is bioabsorbable. A combination of a surgical device (30) for clamping a surgical clip (10) about a suture (24) and the clip (10), said clip (10) comprising first and second opposed leg members (11 and 12) and said device (30) comprising a handle (31) having a base (36) and an activating trigger (37) movably attached to said base (36), clamping jaws (32) having first and second opposed clamping members (33 and 34) configured to grasp said first and second opposed leg members (11 and 12) of said clip (10), and a tubular shaft (35) for connecting said handle (31) to said clamping jaws (32); characterised in that the clip is composed of a polymeric material that softens when heat is applied to it and the device (30) also comprises a heating element (32) disposed on said first clamping member, a first means for activating said heating element (32) such that when said clip (10) is grasped in said clamping jaws (32) and said heating element (32) is activated, causing said polymeric material from which said clip is composed to be heated and hence softened, and means for delivering a compressive force to said first and second opposed clamping members (33 and 34) of said clamping jaws (32) so as to close said first second opposed leg members (11 and 12) of said clip (10) about said suture (24) then said polymeric material is in a softened state. The surgical device (30) of Claim 21 wherein said base (36) of said handle (31) has a contact switch (38) disposed on the surface thereof. The surgical device (30) of Claim 22 wherein said first and second means are activated by squeezing said trigger (37) of said handle (31) so as to cause contact between said trigger (37) and said contact switch (38) thereby activating said switch (38).

Inventors: BREGEN MICHAEL, LUSCOMBE BRIAN H, BREGEN, MICHAEL, LUSCOMBE, BRIAN H.
Applicants: ETHICON INC, ETHICON INC.
Application year: 1993
Main classification: A61B17
IPC codes: A61B17