GB2097260A - Flexible surgical device for guiding fibrous connective tissue - Google Patents

Abstract

A flexible surgical device 11 for guiding fibrous connective tissue such as tendons and fascia through preformed passages in the body during surgical procedures comprises an elongated elastomeric member 13 having a relatively constant cross section which extends across a major portion of the total length of the device, a tip 12 and an open-ended, substantially hollow flared end portion 15. The tissue to be guided is inserted into and attached to the inside 16 of the flared end portion 15 of the device. The device 11 can be manufactured from a silicone elastomer. <IMAGE>

Description

SPECIFICATION Flexible surgical device for guiding fibrous connective tissue BACKGROUND OF THE INVENTION This invention relates to a flexible surgical device intended to be used during surgical procedures for guiding fibrous connective tissue such as tendons or fascia through preformed passages in the body such as through tendon sheaths or holes bored through bones.

Joints in the hand or foot which have been traumatized or have been deformed as a result of conditions such as rheumatoid arthritis can be restored to relatively normal function through the use of reconstructive surgical techniques. Such surgical techniques often involve re-routing fibrous connective tissue such as tendons or fascia to correct deformities or the effects of trauma.

In the past a number of different techniques have been used to pass tendons from one part of the body to another. One technique involves severing a tendon and guiding it through bones, pulleys, or other anatomical or surgical openings by drilling or cutting a passageway for the tendon when necessary and thereafter drawing the tendon through the passageway using forceps. One disadvantage of this method is that the tendon can be hard to grasp with forceps because it is slippery and wet and can be difficult to route through a passageway, especially a long passageway, because it tends to be somewhat limp in nature.

Another method involves passing a suture through the tendon to be routed and using the suture as a leader which pulls the end of the tendon through the preformed passageway. Problems can also arise with this method because, typically, the cut end of a tendon is blunt and resists being drawn through a passageway such as a tendon sheath or pulley, especially if the tendon is slightly larger in diameter than the passageway.

Various types of instruments have been designed for use in passing tendons through other parts of the body such as Bunnell Tendon Passer and Forwarding Probes, catalog number OS5515 and 0S5520, which are available from V. Mueller and Company, Chicago, Illinois. These instruments have a long tip, a flattened oval central region and a flared end opposite the tip. However, these devices are made of metal and while they are useful in guiding tendons through long passages, the rigid metal can traumatize or irritate soft tissue as it is passed through parts of the body and, can puncture a tendon sheath or pulley rather than following the natural course of the passageway.Furthermore, in order to use this instrument to pass a tendon through a bone, the passageway drilled through the bone must be at least as wide as the widest portion of the instrument since metal would not be expected to bend inward to match the size of the tendon to be passed.

Another technique used to pass tendons through parts of the body is described in Dow Corning Corporation New Product Information Bulletin:51-466 dated June, 1978, relating to the SilasticB Tendon Spacer H.P. (Swanson-Hunter Design).A two stage procedure is described wherein in Stage I, the silicone elastomer Tendon Spacer is implanted within a reconstructed tendon bed of the hand and in Stage II, it is replaced by a tendon graft.

The Tendon Spacer is replaced by a tendon graft by suturing one end of the tendon graft to one end of the Tendon Spacer and the Tendon Spacer is then pulled out with the tendon graft following behind. One potential disadvantage with this technique is that the blunt end of the tendon graft could irritate of tear the surrounding tissue as it follows the Tendon Spacer or else the tendon graft itself could be severely traumatized, especially if the tendon graft is slightly larger in diameter than the Tendon Spacer.

There is still a need for a surgical device for passing flexible connective tissue such as tendons or fascia through preformed passages in the body which is simple and convenient to use. It should be manufactured from a material which presents a minimum of potential for tissue damage during use and should enable a surgeon to position such tissue in difficult to reach locations in a reasonably short amount of time. Such a device should also have a simple means by which such tissue can be attached to the device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flexible surgical device which is useful for guiding fibrous connective tissue through preformed passages in the body which minimizes the potential for damage to the fibrous connective tissue itself and also to pulleys, tendon sheaths and other parts of the body that such tissue must be guided through because it is manufactured from a soft and flexible elastomeric material. It is not intended to be used to pierce parts of the body, but to be guided through preformed passageways with, for example, a tendon following behind.

The elastomeric material is more readily grasped by surgical instruments and the flexibility of the device enables it to be used to guide tendons through complex passages in the body and therefore reduces the operating time needed to place a tendon in difficult to reach locations in the body.

Another significant advantage of the present device is the hollow elastomeric flared end which serves a dual purpose. First, it is a convenient site for attaching the end of tendon to the device by simply suturing the tendon through the solid part of the device.

Second, it serves to gradually widen the passageway through which the tendon is to be passed, but does not make a passageway much larger than the tendon itself because the wider portion of the flared end collapses against the sides of the tendon and apprnxi mates the size of the tendon itself. The flared end reduces the possibility that tissue irritation or trauma will occur since the blunt end of the tendon is contained within the smooth flared end portion. The flared end can accommodate a variety of tendon diameters. The elastomeric flared end also has an advantage when the device is used to pass tendons through bone since the hole drilled in the bone need only be slightly larger in diameter than the diameter of the tendon itself.

It is a further object of this invention to provide a flexible surgical device as described above which in a preferred embodiment is manufactured from a flexible silicone elastomer which has the advantages of being easily molded as a one piece unit, readily sterilized prior to use, disposable after a single use and possesses a relatively low friction surface which enables the device to be passed through complex passageways in the body.

These and other objects are provided by a flexible surgical device for guiding fibrous connective tissue through preformed passages in the body comprising an elongated elastomeric member of relatively constant cross section which extends across a major portion of the total length of the device, a first elastomeric flared end portion and a second elastomeric end portion opposite the first which functions as a tip; substantially all of said flared end portion being hollow, the remainder of the device being solid, and said flared end portion being open-ended and being of sufficient length to facilitate insertion of an end portion of said tissue into said open end of the device to enable its attachment to the inside of said flared end portion.

In a preferred embodiment, the device is manufactured from a flexible silicone elastomer, the elongated elastomeric member has a flattened, oval configuration which approximates the shape of a tendon, at least a portion of the member has a relatively constant cross section wich its extremity tapering toward the center of the member to form a tip, the length of the member having a relatively constant cross section is equal to at least 85 percent of the total length of the device and the widest diameter of the flared end portion is no greater than three times the widest diameter of the member having a relatively constant cross section.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become apparent to those skilled in the art upon an examination of the following description and accompanying drawings which are merely illustrative of the present invention.

In the drawings: Figure 1 is a plan view of a preferred embodiment of the flexible surgical device of the present invention.

Figure 2 shows a perspective view of the device of Fig. 1 taken from the side to show the flattened configuration of the device.

Figure 3 is a view of the device shown in Fig.2 taken from the rear along section line 3-3 showing the flattened, oval configuration of the device.

Figure 4 is a cross sectional view of the device 11 taken along section line 4-4 of Fig.3 showing the solid, relatively constant ; eross sectional area which extends back from the tip to the hollow flared end.

Figure 5 depicts the manner in which a flexible surgical device of the present invention can be used.

Figure 6 shows the preferred procedure for attaching a tendon to the flexible surgical device of the present invention.

DETAILED DESCRIPTION OF THE INVEN TION For the purposes of the present invention, the following terms will be defined. "Preformed passages" is intended to mean a passage through some part of the body which has been formed prior to attempting to use the flexible surgical device. A preformed passage can be a pre-existing passage such as a tendon sheath or pulley or else a passage which is cut or drilled through some part of the body such as a ligament or a bone. The flexible surgical device of the present invention is not intended to pierce parts of the body, but to guide flexible connective tissue through such passages. The term "fibrous connective tissue" includes tendons, fascia and the like.

Referring to the drawings, Figs. 1 and 2 show two views of a preferred embodiment of the flexible device 11 of the present invention which comprises an elongated elastomeric member 13 having a relatively constant cross sectional area which starts at one end of the device which tapers toward and meets at the center of member~13 to form a tip 12.

Member 13 extends back from tip 12 towards the opposite end of device 11 and remains relatively constant in cross section across a major portion of the total length of the devce until point 14 on device 11 is reached. At point 14, the device 11 begins to taper outward away from the center of the tube to form a flared end 15 having a hollow interior region 16 which includes substantially all of the area inside the flared end 15. Flared end 15 is both open-ended as shown by reference numeral 17 and is of sufficient length to facilitate insertion of an end portion of flexible connective tissue into the opening in flared end 15 to enable the tissue to be attached to the inside of flared end 15. Figs. 1 and 2 show that the tapering of the outside flared end 15 stops near the end 17 of the device and is relatively constant in diameter for a short distance until point 17 is reached.This constant diameter region can extend farther along flared end 15 or can be eliminated provided that major portion of flared end 15 is tapered to enable the flared end 15 to guide flexible connective tissue through preformed passageways. The simplest and preferred type of flared end is one which gradually and continuously tapers outward from the center of the device at point 14 to point 17.

Figs. 1 and 2 have been discussed together since the preferred embodiment shown in those figures has a flattened, oval configuration and Fig. 1 shows a plan view of device 11 depicting the side of device 11 having the largest cross section while Fig. 2 shows a side view of the device 11 depicting the side of device 11 having the smallest cross section.

Fig. 3 is a view of the device 11 as shown in Fig. 2 taken from the rear along section line 3-3 and more clearly shows the preferred flattened, oval configuration of the device of the present invention. Fig. 3 shows the interior of flared end 15 of device 11 and the beginning of what will become elastomeric member 13 as seen from the inside of flared end 15. The flattened, oval configuration is preferred when the device is used to guide tendons because such a configuration approximates the shape of a tendon.

Fig. 4 shows a cross sectional view of device 11 taken along section line 4-4 of Fig.

3 showing the area of relatively constant cross section which extends from tip 12 along the device up to point 14. Fig. 4 shows the hollow interior region 16 of flared end 15 while the remainder of device 11 is a solid elastomeric material. The solid region includes tip 12, member 13, the sides of flared end portion 15 and extends slightly past point 14 into flared end 15 thereby leaving substantially all of said flared end hollow. This extension of the solid region into a small portion of the flared end is preferred because it provides a convenient and relatively secure area to insert sutures into device 11 for the purpose of attaching a tendon or other fibrous connective tissue to flared end 15.Another advantage of this extension is that it serves to provide a stronger area on the flared end which aids in slightly widening a preformed passage in soft parts of the body to allow a larger diameter tendon to be drawn through such a passage. The elastomeric tip 12 of device 11 is shown as being slightly rounded which is a preferred configuration because it enables the flexible surgical device 11 to follow complex tunnels and pulleys in the body with less chance that the tip of the device will stop as it is being pushed through such a part of the body.The term "tip" also applies to other configurations such as one wherein at least a portion and preferably, all, of the extremity of elastomeric member 13 tapers toward the center of said elastomeric member 13 to form a tip and the taper can be gradual to form a pointed tip or relatively sharp over a short distance to form a slightly rounded configuration. The end portion of the device functioning as a tip can even be blunt, particularly when the device is manufactured from a material having a relatively low friction surface such as silicone rubber, because the elastomer does not tend to spread apart or shred in the manner that a piece of fibrous connective tissue can when the edges of the tissue are caught on the edge of a passageway.Preferably, at least a portion of the extremity of the elastomeric member having a relatively constant cross section tapers toward the center of the member to fcrm a tip.

Fig. 5 shows one method of using the flexible surgical device of the present invention to guide a tendon through a pulley system in a patient's finger. Referring to Fig. 5, a side view of finger 55 is shown with a portion of the skin and other internal parts omitted for clarity. Flexible surgical device 11 has been passed through an incision in the hand (not shown) into a preformed passage in the body, namely the pulley system of finger 55. The end of tendon 50 has been sutured to flared end 15 of device 11 by means of suture 51.

Device 11 is passed through the pulley system by grasping member 13 and pushing the tip of the device 11 into the pulley system (not shown). The tip follows the passage, passes through pulleys 52 and 53 and is retrieved when it reaches incision 54. Member 13 is then grasped with forceps and pulled through the pulley system with tendon 50 trailing behind. The sutured end of tendon 50 that has been attached to flared end 15 is then removed and can then be sutured, for example, to the end of tendon 60 located on the middle phalanx 58. As shown in Fig. 5, the pulley system of finger 55 runs over one surface of metacarpal bone 56, the proximal phalanx 57, the middle phalanx 58 and the distal phalanx 59.

The preferred procedure for attaching tendon 50 to device 11 is shown in Fig. 6. The distal end of tendon 50 is sutured in a figureof-eight fashion with a double armed 4-0 or 5-0 non-absorbable monofilament suture 51.

The needles 60 are inserted into hollow region 16 of flared end 15 and are passed through the solid portion in the center of device 11 and exit near point 14. The sutures should not be passed through the thinner sides of flared end 15 because that will increase the possibility of having the sutures tear through the device 11 when attempting to guide a tendon through a tight fibro-osseous, osseous or subcutaneous preformed passage in the body. The sutures are then snugged tightly and tied securely so that the end of the tendon will be firmly attached within flared end 15 and, preferably, the end of the tendon is drawn up against the solid portion of device 11 through which the suture needles have been passed.

The device itself can be manufactured from any biocompatible elastomeric material which can undergo the necessary sterilization procedures required for surgical instruments. The elastomeric material should be soft to avoid the tissue damage that can occur when metal instruments are used and should be resilient and resistant to tearing. Examples of elastomeric materials which may be useful in producing devices of the present invention are biocompatible materials such as polyvinyl chloride elastomer, silicone elastomer and other flexible elastomeric materials known to be useful in medical devices and preferably, a silicone elastomer is used.The most preferred flexible elastomeric material is a high tear strength silicone elastomer having tear strength of at least 275 p.p.i. (Die B, ASTM D624), a tensile strength at break of at least 1100 p.s.i. (Die C, ASTM D412), an elongation at break of at least 500% (ASTM D412) and a durometer valve of 50-60 (Shore A, ASTM D2240). To further improve the tear strength of the flexible surgical device of the present invention, it can be advantageous to include a known biocompatible, reinforcing agent such as a polester mesh, cloth fabric, soft fibers, or the like within the solid portion of the device.Preferably, the device is transfer-moulded in a single cavity mold according to well-known manufacturing techniques to produce a single piece unit since the simplest and potentially strongest configuration is one wherein the tip, the relatively constant cross section member and the flared end are one intergral unit.

Referring to Fig. 1, the preferred embodiment of the device of the present invention is a flexible surgical device for guiding tendons which is manufactured from a silicone elastomer wherein the length of member 13 measured from tip 12 to point 14 is at least 85 percent of the total length of the device as measured from tip 12 to end 17. It will be obvious to those skilled in the art that the length of flared end 15 measured from point 14 to end 17 must be at least long enough to enable the flared end 15 to fit over the end of a tendon of other flexible connective tissue and allow it to be attached to the inside of flared end 15. In this preferred embodiment, the widest diameter of flared end 15 which is typically found at point 17 is no greater than three times the widest diameter of member 13.While alternative embodiments of the devices of the present invention can have a round configuration, the most preferred configuration of the device is that of the flattened, oval configuration shown in Fig. 3.

A device of the present invention was prepared by transfer molding the device in a single cavity mold using a composition which cured to a high tear strength silicone elastomer. Referring to Fig. 4, the distance between tip 12 and the point on flared end 15 where the solid region stops and hollow region 16 begins was about 12.8 centimeters (cm) and the total length of the device was 14 cm. The length of flared end 15 measured from point 14 to point 17 was about 1.8 cm.

The diameter of flared end 15 measured at its widest diameter at point 17 was 6 millimeters (mm) and its narrowest diameter at point 1 7 was 3 mm. Member 13 was 3 mm in diameter at its widest diameter point and 1.5 mm at its narrowest diameter along the region of constant cross section. The above described device was successfully used in surgical procedures conducted on the hand.

Other lengths and diameters can be selected depending upon the diameter of the tendon or other flexible connective tissue that the device is intended to guide. For example, a slightly longer embodiment of the flexible surgical device of the present invention shown in Fig. 4 can be one wherein the total length of the device is 17.5 cm and the distance between the tip 12 and the point on flared end 15 at which the solid region stops and hollow region 16 begins is 15.7 cm. In this embodiment, the length of flared end 15 measured from point 14 to point 17 is about 1.8 cm and the diameter of flared end 15 measured at its widest diameter at point 17 is 0.68 cm and its narrowest diameter is 0.43 cm. Member 13 can be 3 mm in diameter at its widest diameter point and 1.5 mm in diameter at its narrowest point along the region of constant cross section. Longer devices may be required for surgical procedures involving the knee or foot. If the device is too long for the procedure being used, the surgeon can simply cut off the excess portion from the end opposite the flared end portion.

Other modifications and variations of the flexible surgical device of the present invention will become apparent to those skilled in the art from an examination of the above specification and drawings. Therefore, other variations of the present invention may be made which fall within the scope of the appended claims even though such variations were not specifically discussed above.

Claims (6)

1. A flexible surgical device for guiding fibrous connective tissue through preformed passages in the body characterized by an elongated elastomeric member of relatively constant cross section which extends across a major portion of the total length of the device, a first elastomeric flared end portion and a second elastomeric end portion opposite the first which functions as a tip; substantially all of said flared end portion being hollow, the remainder of the device being solid, and said flared end portion being open-ended and being of sufficient length to facilitate insertion of an end portion of said tissue into said open end of the device to enable its attachment to the inside of said flared end portion, said flared end portion further being collapsible upon said tissue and capable of regaining its shape upon release of external pressure thereon.

2. A flexible surgical device as claimed in claim 1 wherein the device has a flattened, oval configuration.

3. A flexible surgical device as claimed in claim 1 wherein at least a portion of the extremity of said elongated elastomeric member tapers toward the center of said member to form a tip.

4. A flexible surgical device as claimed in claims 1, 2 or 3 wherein the device is manufactured from a flexible silicone elastomer.

5. A flexible surgical device as claimed in claims 1, 2 or 3 wherein the length of the member having a relativaly constant cross section is equal to at least 85 percent of the total length of the device and wherein the widest diameter of said flared end portion is no greater than three times the widest diameter of the member having a relatively constant cross section.

6. A flexible surgical device as claimed in claim 1 substantially as herein described with reference to the accompanying drawings.