TWI528936B - A system for cutting ligaments or soft tissues within the body - Google Patents

Description

A system for cutting ligaments or soft tissues in the body

The present invention relates to a surgical system. More particularly, the present invention relates to a system for cutting ligaments or soft tissues in a body that crosses a ligament, such as a wrist ligament, with minimal interventional means, typically by releasing the wrist ligament to treat carpal tunnel syndrome .

Often due to the frequent, continuous repetitive movements of the hand, the soft tissues of many people's wrists and carpal tunnels are damaged. The damage caused by the repetitiveness of hand and wrist movements is collectively referred to as cumulative repetitive stress syndrome or repetitive strain. One of the most familiar and common wrist injuries is called carpal tunnel syndrome. Carpal tunnel syndrome causes pain, discomfort, nerve conduction disorder and dysfunction in the hands, and sometimes causes the arm to produce the above situation. The most common symptoms of this type of condition include intermittent pain and numbness in the hands.
Carpal tunnel syndrome occurs when the median nerve extending from the forearm to the hand is compressed or squeezed at the wrist. The median nerve provides a sense in the human thumb, index finger, middle finger, and ring finger. The median nerve controls the perception of the palm side of the thumb and these other fingers and the nerve impulses that are transmitted to some of the muscles in the hand that allow the fingers and thumb to move. The median nerve receives blood, oxygen, and nutrients through the microvasculature, which is present in the connective tissue surrounding the nerve fibers. An increase in the pressure on the nerve fibers causes the microvasculature to contract and reduces the flow of blood to the median nerve. Long-term lack of oxygen and nutrition can cause severe nerve damage.
The median nerve passes through the carpal tunnel, which is a tube located in the wrist. The three sides are surrounded by the carpal bone, and the fourth side is surrounded by a fibrous sheath called the lateral carpal ligament. In addition to the median nerve, nine flexor tendons in the hand also pass through the tube. When stressed, the median nerve can cause pain, weakness, or numbness in the hands and wrists that can radiate upward along the arm. The median nerve may be compressed by a decrease in the size of the carpal tunnel itself, or an increase in the size of the contents of the carpal tunnel (i.e., swelling of the flexor tendon and the smooth tissue surrounding these flexor tendons), or both. For example, a situation in which the flexor tendon is stimulated or the flexor tendon is inflamed can cause swelling of the flexor tendon. Stimulation of the stimulated flexor tendon or swelling of other tissues within the tube causes the carpal tunnel to narrow, thereby compressing the median nerve. The cross-sectional area of the carpal tunnel also changes when the hand or wrist changes position. Bending or stretching of the wrist causes the cross-sectional area to become smaller, thereby increasing the pressure acting on the median nerve. Bending the wrist also causes a certain rearrangement of the flexor tendon, which also forces the median nerve. For example, simply bending the wrist at a 90 degree angle will reduce the size of the carpal tunnel. If left untreated, carpal tunnel syndrome can cause chronic neuromuscular discomfort in the hand and sometimes cause chronic neuromuscular discomfort in the arm.
The treatment of carpal tunnel syndrome includes a variety of non-surgical methods and surgical methods, of which carpal tunnel loosening is one of the most common surgical methods. This surgical approach involves cutting the transverse carpal ligament to relieve pressure on the median nerve and is typically performed by either an open or endoscopic approach. In the open procedure, the skin above the carpal tunnel is cut and the transverse carpal ligament is transected with direct visualization. Then use suture to reattach the skin. Endoscopic methods require the skin to be cut at one or more locations to allow for the insertion of the endoscope and the various tools required to transect the ligament. Such tools typically include a combination of specially constructed scalpels and guiding instruments. Inserting such tools below, above, or above and below the target ligament also requires the formation of one or more channels in the hand that can cause concomitant trauma to the surrounding tissue, potential damage to the nerve, And a longer postoperative recovery period. In addition, the use of a scalpel typically requires the scalpel to pass through the passage multiple times to complete the transection, which creates a complex cut pattern on the surface of the severed ligament.
Techniques that have been proposed to be less invasive include, for example, the use of a flexible saw element that is introduced into the interior of the hand and positioned adjacent to or around a target ligament, and then reciprocating the flexible saw element to cut tissue. A significant disadvantage of incisions formed by saw-type instruments compared to knife-type instruments is that they inherently create a kerf. Substances removed from the kerf are either deposited in the surgical site and near the surgical site, or removed by additional steps that must be taken. In addition, the cutting surface produced by the sawing device tends to be rough and bruised, and micro-injury on the cutting surface increases the inflammatory response (edema, erythema, fever and pain), which can lead to local tissue adhesions and scarring, which can be prolonged. Rehabilitation time can complicate the healing process.
Alternatively, there is a method of cutting a ligament using a tensioned wire, string or filament. Cutting is performed by tensioning the cutting element or by reciprocating the tensioned cutting element. A disadvantage with this method is that the arrangement of the cutting elements is such that other portions adjacent to the target ligament also enter the cutting range and it is difficult to form the starting point of the slit. The optimal path should be such that the cutting element is only loaded onto the target ligament and the cutting force is concentrated at the beginning of the incision. In addition, the use of a tensioning device for cutting also causes an unnecessary increase in wounds.
Therefore, there is a need for a new system that penetrates the skin through a pinhole to reach a tissue such as a ligament and cuts it, while having only a minor effect on the surrounding tissue, thereby achieving a smooth, knife-like incision.

The present invention relates to cutting soft tissues such as ligaments in a minimally invasive manner. The system of the present invention does not require any incision to the skin, minimal damage to tissue surrounding the target ligament, can form a sharp, knife-shaped incision that smoothes the target ligament, does not require suturing, and can be easily and quickly performed under clinic conditions. Implementation.
More specifically, the present invention relates to the introduction of a small, flexible, linear cutting assembly into the body and surrounding it around the target ligament. The ends of the cutting assembly are then manipulated to traverse the ligaments to create a smooth, knife-like cut. The specially constructed retrieval tool of the present invention enables easy and rapid guidance of the cutting element and placement to a position around the target ligament with minimal disruption or damage to surrounding tissue. The retrieval tool component includes an elongated, rigid needle-like distal portion that is formed with an open pin-eye contact structure in the retrieval tool adjacent the distal end of the retrieval tool. The detachment structure is sized to engage the retrieval tool with the cutting element and to remain engaged with the cutting element as the retrieval tool is moved by the pulling force.
When transversing the transverse carpal ligament, the skin of the hand is first pierced using a retrieval tool, forming a first channel position near the proximal end of the ligament and laterally adjacent the ligament. The retrieval tool is then inserted into the hand through the carpal tunnel along a path just below the ligament and is projected from the hand at a second channel position just at the distal end of the ligament. The position of the retrieval tool within the hand and in particular the position of the retrieval tool relative to the ligament is displayed by means of a positioning measure performed by, for example, an ultrasound imaging device, so that the retrieval tool can be accurately manipulated. The pick-up mechanism of the retrieval tool engages a length of cutting element to pull the fold-back structure formed by the cutting element into the hand through the second channel position. The zero bend radius of the cutting element allows the formation of a foldback structure that does not take up as much space as possible. The foldback structure is pulled under the ligament and pulled out of the first channel position, then the cutting element is disengaged from the retrieval tool and the first free end of the cutting element is pulled through the hand. Re-inserting the retrieval tool into the hand and extending along the upper interface of the ligament to the second channel position, causing the retrieval tool to engage the second segment of the cutting element and pulling the retraction structure of the cutting element into the hand, over the ligament and from The first channel position is pulled out. The second free end of the cutting element passes through the hand, over the ligament and is pulled out of the first channel position, completing the operation of arranging the cutting element around the ligament such that the cutting element is in a position for transection. The cross-section of the retrieval tool and the cutting element is very small, and the method of introduction and positioning of such a tool in the hand is very small, greatly reducing the risk of damaging the median nerve and the smaller nerves branching therefrom. Furthermore, the cutting element is positioned only by two small perforations and cross-cutting is performed by one of the two perforations, which makes the healing time shortest and makes the scar formed substantially negligible.
The physical properties of the cutting assembly are selected to enable the ligament to be cut without kerf. The small diameter and high tensile strength of the cutting element enable transection of the ligament by manipulating the end of the cutting element. Unequal forces can be alternately applied to both ends of the cutting element to create a reciprocating cutting action. Alternatively, one end can be pulled with a greater force than the other end to pull the cutting element in one direction, thereby causing the cutting element to sever the ligament. Alternatively, both ends can be pulled simultaneously with the same amount of force to pull the cutting assembly through the ligament. The smooth, non-abrasive surface of the cutting element enables a knife-like cut to be made without the formation of a kerf, so that the separated material is not concomitantly deposited at or near the cutting site.
The invention may also be modified to further simplify the surgical procedure. For example, the sequence of steps of arranging the cutting elements around the ligament can be altered such that the retrieval tool first passes over the upper portion of the ligament and retrieves the folded back portion of the first end of the cutting element, and then passes the retrieval tool through the carpal tube to retrieve the cutting The folded back portion of the second end of the component. Additionally, a rigid threading positioning tool can be attached to the second end of the cutting element to facilitate engagement of the retrieval tool with the cutting element at a location that is entirely within the hand and thereby closer to the distal edge of the ligament, thereby aligning the ligament with the ligament Any organization in the neighborhood produces the smallest cross-cutting. It is also possible to mark the retrieval tool to allow its orientation to be determined when the removal element is in the hand, thereby increasing the ability of the retrieval tool to engage the cutting element. Additionally, a protective tube surrounding a portion of the cutting element can be employed to protect tissue between the proximal inlet and the ligament. Both ends of the cutting element can be passed through a single protective tube, or each end of the cutting element can be passed through its own protective tube.
These and other advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention.

10. . . hand

12. . . Carpal tunnel

14. . . bone

16. . . Lateral carpal ligament

18. . . Median nerve

20. . . Flexor tendon

twenty two. . . Retrieval tool

twenty four. . . Remote part

26. . . handle

28. . . Pick-up structure

29. . . top

30. . . remote

32. . . mark

34. . . Cutting element

34a, 34b. . . Ends

36. . . Threading positioning tool

38. . . Rigid distal end

40. . . handle

42. . . Entrance

44. . . Export

46, 48. . . Foldback structure

50. . . Protective tube

52. . . Remote accessory

54. . . Hypodermic needle

56. . . Locking mechanism

58. . . Handle

60. . . section

Figure 1 is a cross-sectional view of the carpal tunnel area of the hand;
Figure 2 is a perspective view of an embodiment of the retrieval tool of the present invention;
Figure 3 is a perspective view of an embodiment of the cutting assembly of the present invention;
4A through 4H are perspective views of a hand with a wrist ligament shown, showing the sequence of steps for performing the method of the present invention;
5A-5C are cross-sectional views of the hand and transverse carpal ligaments showing the steps for performing the method of the present invention;
6A and 6B are cross-sectional views of the hand and transverse carpal ligament showing an alternative embodiment utilizing a protective tube; and FIGS. 7A and 7B are high magnifications of an alternative embodiment of the retrieval tool Enlarged section view.

The present invention relates to cutting soft tissue in a manner that is minimally invasive and does not require the use of a scalpel, saw or endoscope. The invention is particularly suitable for use in cutting ligaments and is most suitable for use in the treatment of carpal tunnel syndrome to loosen the transverse carpal ligament.
FIG. 1 is a cross-sectional view of the carpal tunnel region of the hand 10. The carpal tunnel 12 is an area of the wrist and palm of the hand 10 that is formed by a U-shaped set of bones 14, which form the hard bottom and the two walls of the carpal tunnel. The top of the carpal tunnel is formed by a transverse carpal ligament 16 attached to the carpal bone. The median nerve 18 and flexor tendon 20 of the thumb and other fingers are located inside the carpal tunnel. The size of the carpal tunnel becomes smaller or the size of the carpal tunnel contents is increased to cause the median nerve to be compressed, thereby causing carpal tunnel syndrome. This compression can be mitigated by, for example, loosening the ligaments transversely to the ligament.
2 is a perspective view of a preferred embodiment of the retrieval tool 22 of the present invention. The retrieval tool primarily includes an elongated rigid needle shaped distal portion 24 and a proximally located handle 26. The distal portion 24 has an open pin-eye attachment structure 28 disposed adjacent its distal end 30. The detachment structure 28 is formed by an open eye formed in the outer surface of the distal end portion 24 of the retrieval tool 22 to provide the distal portion 24 with a smoothest outer surface for insertion of the retrieval tool 22 into the tissue or from Pulling back in the tissue minimizes the possibility of trauma. The distal portion 24 can have a pointed tip 29 as shown in the illustrated embodiment. Alternatively, the tip can have a blunt configuration. The pick-up structure 28 is slightly offset rearward from the distal end 30. Indicia 32 may be provided on the handle 26 to distinguish the direction of the pick-up structure 28 adjacent the distal end 30 of the retrieval tool 22. The length of the distal portion 24 is selected to be greater than the width of the transverse carpal ligament. The diameter of the distal portion 24 is selected to be no greater than about 1 mm.
3 is a perspective view of the cutting element 34 of the present invention with an optional rigid threading positioning tool 36 attached to the cutting element 34. The cutting element has a flexible, small diameter, wire-like structure with high tensile strength and a smooth surface with a surface roughness of no more than 50 microns. The cutting elements can comprise monofilaments or a plurality of fibers or strands that are joined by weaving or other means, wherein each strand has a smooth surface to present a relatively smooth, non-abrasive surface. Physical properties include: a bend radius less than half the thickness of the ligament, preferably zero; a diameter less than about 1.0 mm, preferably less than 0.5 mm; and a tensile strength greater than 500 MPa. The cutting element may comprise fibers or yarns formed from cotton, silk, fiberglass, carbon fibers, various plastic fibers or metal fibers. More specifically, woven fabrics, synthetic fibers, mineral fibers, polymer fibers, microfibers can be used to form the cutting assembly. The optional threading positioning tool 36 includes a rigid distal end 38 that is sufficiently small in diameter to be able to extend into and be retained within the pick-up structure 28 of the retrieval tool 22. The handle 40 is disposed proximate the proximal end of the positioning tool 36 to enable the positioning tool 36 to be grasped and manipulated.
Figures 4A through 4H illustrate preferred methods of practicing the invention. After anesthesia is applied to the region of the hand 10 and the region surrounding the lateral carpal ligament 16, as shown in Fig. 4A, the distal end 30 of the retrieval tool 22 is brought into contact with the portion of the hand that is closest to the proximal edge of the target ligament. The ligaments are shown for clarity only, as no incision is performed throughout the procedure to expose the ligaments in any way for viewing. Furthermore, the position of the retrieval tool relative to the ligament is displayed using an imaging device such as, for example, an ultrasonic device commonly used for various imaging purposes, but the imaging device is not shown to prevent it from obstructing the surgical position, which is also for the purpose of clarity. Preferably, the retrieval tool enters the hand at a position about 30 mm from the proximal edge of the transverse carpal ligament, since the carpal tunnel can then be accessed at a shallower angle so that no adjustments need to be made after the carpal tunnel is reached. The angle of the tool and minimizes trauma to the tissue. In addition, this also allows for easier imaging of the retrieval tool.
In Figure 4B, the retrieval tool enters the hand through the inlet 42 (the first channel position, or the first position), just below the ligament through the carpal tunnel and through the outlet 44 (the second channel position, or the second position) ) stretched out. Where the retrieval tool 22 is selected to have a pointed tip 29, the inlet 42 and the outlet 44 can be formed by directly passing the retrieval tool through the skin. Where the retrieval tool used has a blunt end, a sharp instrument is required to form the inlet and guide the retrieval tool into the hand. Also shown is the engagement of the cutting element 34 with the detachment structure 28 proximate the distal end of the retrieval tool. In this particular embodiment, the rigid threading positioning tool is not attached to the distal end of the cutting element.
As shown in FIG. 4C, after the cutting element 34 is engaged with the detachment structure 28, the retrieval tool 22 is pulled back from the hand to pull the retraction structure 46 formed by the cutting element into the hand through the outlet 44, through the carpal tunnel. And pulled out from the entrance 42. As shown in Fig. 4D, the foldback structure 46 is then disengaged from the retrieval tool 22, and the foldback structure 46 is pulled to hold the end portion 34a of the cutting element 34 while holding one end 34a of the cutting element stationary. The opposite end 34b is pulled out of the hand.
Figure 4E shows a subsequent step of the method in which the retrieval tool is again inserted into the hand through the inlet 42 over the upper interface of the ligament 16 and out of the hand through the outlet 44. The portion of the cutting element 34 that projects from below the ligament is engaged with the detachment structure 28 of the retrieval tool 34.
As shown in FIG. 4F, after the cutting assembly 34 is again engaged with the detachment structure 28, the retrieval tool 22 is pulled back from the hand to pull the retraction structure 48 formed by the cutting element into the hand through the outlet 44, through the wrist. The tube is pulled out from the inlet 42. As shown in Fig. 4G, the foldback structure 48 is then disengaged from the retrieval tool, and while the one end 34b of the cutting element is held stationary, the foldback structure is pulled to pull the end 34a of the cutting element from the hand. Out. Thereby the cutting element is in a position around the ligament 16 in order to perform a subsequent operation for cross-cutting. As shown in Fig. 4H, the ends 34a, 34b of the cutting element can simply be grasped by the user, can be wrapped around the user's hand or fingers for secure grasping, or can be attached to the handle for maximum grasping. Grip and control. Unbalanced forces can be alternately applied to the two ends 34a, 34b of the cutting element to reciprocate the cutting assembly. Alternatively, one end can be pulled with a greater force than the other end to pull the cutting element in one direction, thereby cutting the cutting element through the ligament. Alternatively, the two ends 34a and 34b can be pulled simultaneously with the same amount of force to pull the cutting assembly through the ligament. After the cross-cutting is completed, it is only necessary to pull the cutting element through the inlet 42. A small bandage is wound around the inlet 42 and the outlet 44, respectively, to complete the entire process.
In an alternative embodiment, as shown in FIG. 5A, as a modification of the step shown in FIG. 4C, the retrieval tool 22 is not completely pulled out of the inlet 42. The retrieval tool is pulled out to a position just enough to expose the detachment structure 28 and allow the foldback structure 46 formed by the cutting assembly 34 to be disengaged and pulled out of the retrieval tool, while the majority of the remote 30 remains under the skin . As a result, the retrieval tool is more likely to move along the same path before the retrieval tool reaches the upper surface of the ligament 16, which can cause trauma and damage to the tissue involved in the insertion of the retrieval tool and the completion of the transection step. small.
In an alternative embodiment, as shown in FIG. 5B, as a modification of the step shown in FIG. 4E, the retrieval tool 22 does not extend through the outlet 44 to engage the cutting assembly 34. Conversely, the cutting assembly 34 engages the retrieval tool 22 within the hand, preferably at a location as close as possible to the distal end of the lateral carpal ligament 16. The opening direction of the pick-up structure 28 of the retrieval tool shown in the drawing faces the viewer. The indicia on the handle 26 allows the user to determine the orientation of the pick-up structure without directly viewing the remote of the retrieval tool. By engaging the cutting element 34 with the retrieval tool at a location near the distal end of the ligament, and then pulling the cutting element 34 over the upper interface of the ligament, as much as possible to wrap less excess tissue between the cutting element and the ligament, thereby transversing The ligaments cause less trauma to the tissue.
As a further improvement of the preferred embodiment illustrated in FIG. 5B, FIG. 5C illustrates the use of a cutting element 34 coupled with a rigid threading positioning tool 36. As determined by ultrasound imaging, once the distal end 30 of the retrieval tool is in place such that the attachment structure 28 is located remotely from the distal edge of the lateral carpal ligament, the end of the cutting assembly 34 that is outside the inlet 42 is pulled. 34b, in order to pull the opposite end 34a and the rigid threading positioning tool 36 connected to the end 34a into the outlet 44. Once the rigid distal end 38 of the positioning tool 36 reaches the appropriate depth shown, the cutting element 34 can be more easily engaged with the retrieval tool 22 by the visibility and tactile feedback of the positioning tool under ultrasound imaging, wherein the tactile feedback This is produced when contact occurs between the rigid distal end portion 24 of the retrieval tool 22 and the rigid distal end 38 of the positioning tool 36. Once the cutting element 34 is confirmed to engage the detachment structure 28 of the retrieval tool 22, the positioning tool 36 is pulled from the outlet 44 leaving only the cutting element 34 within the detachment structure 28. Separating the cutting element 34 from the positioning tool 36, and subsequently pulling the retrieval tool 22 such that the folded back formation formed by the cutting element is pulled through the channel above the ligament and pulled out of the inlet 42 and then pulled back the folding structure to The free end 34a is pulled through the hand from the inlet 42 to arrange the cutting element to surround the target ligament.
Where the cutting element 34 is selected to have a bend radius greater than zero, it may be necessary to first introduce a guide line of zero bend radius into the hand and then set the guide line around in the manner described above with respect to setting the actual cutting element. ligament. Once such a guide wire is in place, one end of the guide wire is directly connected to one end of the cutting element and the guide wire is pulled out to replace the guide wire with the cutting element. This method allows the size of the inlet to be minimized, otherwise the inlet is required to be sized to accommodate the larger fold-back structures 46, 48 formed by cutting elements of non-zero bend radii.
As shown in FIGS. 6A and 6B, another alternative preferred method for practicing the present invention includes the use of one or more protective tubes 50 that are disposed to surround the cutting assembly 34 at the inlet 42. Both ends of the cutting element can pass through a single protective tube (Fig. 6A), or each end can pass through its own protective tube (Fig. 6B). The protective tube 50 serves to protect surrounding tissue from damage when a tension is applied to the cutting assembly and the cutting element is pulled or the cutting element is reciprocated for transection. The protective tube acts particularly when the cutting element creates a certain bend in or around the inlet 42. A thin-walled tube that is flexible but capable of withstanding the cutting of the cutting element is selected as the protective tube.
As shown in Figures 7A and 7B, in another alternative preferred embodiment, the modified retrieval tool includes a hypodermic needle 54 and a distal attachment 52 mounted on the hypodermic needle 54, distal attachment 52 has a blunt tip. The hypodermic needle is initially used to form the inlet 42, inject an anesthetic, and/or a liquid (e.g., a saline solution) to expand the surgical site, thereby separating the various tissues and components, making it easier to position the cutting assembly in place. After the injection is completed, the hypodermic needle is extended from the body to form the outlet 44. The distal attachment 52 is inserted into the hypodermic needle and locked in place by the locking mechanism 56 (Fig. 7B). Such a locking mechanism can take any of a variety of forms, including an interference fit formed by the undulating configuration of the handle 58 shown in the figures. As shown in Fig. 4C, after the cutting element is engaged with the retrieval structure 28 of the retrieval tool, the hypodermic needle is pulled back to pull the foldback structure 46 into the hand. The outer diameter of the portion 60 of the distal attachment 52 of the retrieval tool can be selected to substantially match the outer diameter of the hypodermic needle, resulting in a smooth transition.
While the invention has been described with respect to the specific embodiments of the embodiments of the present invention For example, the sequence of steps can be changed such that the retrieval tool first passes over the upper surface of the transverse carpal ligament and retrieves the folded back formation formed by the cutting elements, and then the retrieval tool passes over the lower surface of the transverse carpal ligament. Additional inlets may be formed to make it easier to form the cutting elements around the target. Any one of the channel positions can be used as the final outlet for both ends of the cutting element. Moreover, the methods of the present invention and retrieval tools of appropriate size can be used to transect other tissues to perform, for example, but not limited to, trigger finger release surgery, fistula release surgery, and plantar fascia release surgery. The systems and methods of the present invention can be readily adapted to sever other soft tissues such as, for example, the muscles, tendons, vessels, and nerves of humans and animals. Therefore, the scope of the invention is limited only by the scope of the appended claims.

10. . . hand

16. . . Lateral carpal ligament

twenty two. . . Retrieval tool

28. . . Pick-up structure

34. . . Cutting element

42. . . Entrance

44. . . Export

Claims (26)

A system for cutting a ligament in a body, comprising: a flexible linear cutting element having a smooth surface; a retrieval tool having a rigid needle-like distal portion, the distal portion being of sufficient length to Extending from a first position laterally adjacent the ligament to a second position laterally adjacent to the ligament and opposite the first position, and a top end of the distal portion enabling it to be from the first position Positioning into the body, moving along a side edge of the ligament and extending from the second position, and the distal portion of the detachment structure can be at the second position with the cutting Engaging the component in engagement with the cutting assembly during its return to the first position along the original path and disengaging it from the cutting assembly prior to retracting to the first position; imaging device It is capable of displaying the position of the retrieval tool relative to the ligament. The system of claim 1, wherein the cutting assembly has a diameter of less than 0.5 mm. The system of claim 1, wherein the cutting assembly has a bending radius of zero. The system of claim 1, wherein the cutting assembly has a bend radius that is less than half the thickness of the ligament. The system of claim 1, wherein the cutting assembly has a tensile strength greater than 500 MPa. The system of claim 1, wherein a rigid threading positioning tool is attached to the cutting element, the positioning tool having the distal end portion of the retrieval tool and the cutting element in the The second position is engaged within the body and the positioning tool is then separated from the cutting element before the retrieval tool is retracted along the original path. The system of claim 1, wherein the cutting element has a surface roughness of no greater than 50 microns. The system of claim 1, wherein the detachment structure is an open pin-eye detachment structure located near a distal end of the distal end portion of the retrieval tool. The system of claim 1, wherein the retrieval tool comprises an injection needle and a distal attachment engageable with the injection needle, the distal attachment having the detachment structure. The system of claim 9, wherein the distal attachment has a blunt tip. The system of claim 1, wherein the distal end portion of the retrieval tool has a diameter of no more than 1 mm. The system of claim 1, wherein the imaging device comprises an ultrasound imaging device. The system of claim 1, further comprising: a thin-walled flexible protective tube through which the cutting element passes, and the molding material of the protective tube is such that the cutting element The protective tube is not cut by the cutting element when moving within the protective tube. A system for cutting soft tissue within a body, comprising: a flexible linear cutting element having a smooth surface; a retrieval tool having a rigid needle-like distal portion, the distal portion being of sufficient length to Extending from a first position laterally adjacent to the soft tissue to a second position laterally adjacent to the soft tissue and opposite the first position, and a top end of the distal portion enabling it to be from the first position Positioning into the body, moving along a side edge of the soft tissue and extending from the second position, and the distal portion of the detachment structure can be at the second position with the cutting Engaging the component in engagement with the cutting assembly during its return to the first position along the original path and disengaging it from the cutting assembly prior to retracting to the first position; imaging device It is capable of displaying the position of the retrieval tool relative to the soft tissue. The system of claim 14, wherein the cutting assembly has a diameter of less than 0.5 mm. The system of claim 14, wherein the cutting assembly has a bend radius of zero. The system of claim 14, wherein the cutting assembly has a bend radius that is less than half the thickness of the soft tissue. The system of claim 14, wherein the cutting assembly has a tensile strength greater than 500 MPa. The system of claim 14, wherein a rigid threading positioning tool is attached to the cutting element, the positioning tool having the distal end portion of the retrieval tool and the cutting element in the The second position is engaged within the body and the positioning tool is then separated from the cutting element before the retrieval tool is retracted along the original path. The system of claim 14, wherein the cutting element has a surface roughness of no greater than 50 microns. The system of claim 14, wherein the detachment structure is an open pin-eye detachment structure located near a distal end of the distal end portion of the retrieval tool. The system of claim 14, wherein the retrieval tool comprises an injection needle and a distal attachment engageable with the injection needle, the distal attachment having the detachment structure. The system of claim 22, wherein the distal attachment has a blunt tip. The system of claim 14, wherein the distal end portion of the retrieval tool has a diameter of no more than 1 mm. The system of claim 14, wherein the imaging device comprises an ultrasound imaging device. The system of claim 14, further comprising: a thin-walled flexible protective tube through which the cutting element passes, and the molding material of the protective tube is such that the cutting element The protective tube is not cut by the cutting element when moving within the protective tube.