Primary repair of the severed flexor tendon

Primary repair of the severed flexor tendon

Primary Repair of the Severed Flexor Tendon--H. Bolton P R I M A R Y R E P A I R OF T H E S E V E R E D F L E X O R T E N D O N H. BOLTON, Stockport ...

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Primary Repair of the Severed Flexor Tendon--H. Bolton P R I M A R Y R E P A I R OF T H E S E V E R E D F L E X O R T E N D O N

H. BOLTON, Stockport SELECTION OF CASES

Wounds of the flexor surfaces of the wrist and hand which result in division of the flexor tendons can be caused in a variety of ways. Type o[ Wound The type of wound sustained is of prime importance in deciding on the correct treatment of the underlying tendon injury. Incised wounds such as those caused by knife or glass cuts, are more often suitable for the performance of primary tendon repair than crushing or untidy wounds, such as those caused by circular saws, or crushes under heavy machinery, where the first consideration is to secure early wound healing. In these latter types of wounds, tendon repair is better deferred to a later date. Time Lapse The length of time which has elapsed between injury and primary wound treatment is also important in deciding on the current primary treatment of the divided tendon, and a wound more than eight hours old is probably never suitable for primary tendon repair. Interference Another important point in deciding on the feasibility of primary tendon repair is the amount of interference the wound has suffered since it was sustained. Tendon and nerve damage should be diagnosed by careful distal examination and never by wound exploration in unsterile circumstances. Bleeding, prior to definitive operation, should be controlled by a pressure dressing and elevation and not by blind attempts to catch the bleeding vessels with artery forceps for further damage may be caused if this is not skilfully performed. Infection One thing is certain:--infection must be avoided by thorough wound toilet, and the removal of any devitalised tissue. OPERATIVE TREATMENT

Operation should be performed under general anaesthesia as the bloodless field afforded by a pneumatic tourniquet is an essential part of the procedure. Wound cleaning should be done by thorough lavage with soap and water. Strong antiseptics, for example Iodine in Spirit, should never be used, But Betadine is permissible and Cetavlon useful in removing oil and grease. Accidental wounds are almost always transverse or oblique. They frequently need extension for adequate exploration and this should be done in accordance with accepted principles. Extension in bayonet fashion is often the easiest. Straight, longitudinal, mid-line incisions must be avoided. After careful wound toilet and minimal excision, the extent of the damage can be ascertained. The tourniquet should now be released and haemostasis secured. If tendon repair is performed it must be done carefully and without causing further damage to the tendon and its surrounding structures. Tendons divided by knife or glass cuts frequently require no further trimming. The author finds it nearly impossible to cut a tendon as neatly as the patient manages to do. The tendon end should only be trimmed if it is dirty, cut i n a ragged fashion, or has been crushed by grasping it with forceps. Temporary transfixation of the proximal end of the divided tendon with a fine straight needle 102

Primary Repair of the Severed Flexor Tendon--H. Bolton

is preferable to repeated handling with forceps. Suture material should be fine and either silk or wire used. One or two simple mattress stitches supplemented by one or two fine peripheral sutures of 5 / 0 nerve silk is usually adequate to secure accurate apposition of the tendon ends. A Bunnell type of stitch, though more certain in its hold, does entail entering the tendon surface over a larger area. Separation at the suture line is prevented by immobilisation of the wrist and fingers in flexion and the avoidance of early active movements. Verdan (1960) and Madsen (1963) have used stainless steel wires to transfix the tendon proximal to the suture line, to prevent involuntary movements leading to the separation of the suture line during the period of immobilisation. Boyes (1964) has used a pull-out wire placed proximally with the same object. As previously mentioned, temporary tendon transfixation has been found helpful in the actual operation but has not been continued post-operatively, reliance being placed on immobilisation in the relaxed position and the avoidance of active movement. Carefully performed primary repair should not prejudice a subsequent tenolysis or tendon grafting procedure, should either become necessary. DRESSING

Wound closure must be careful and the hand is dressed subsequently in a compression dressing of fluffed gauze and crepe bandages to promote haemostasis, and prevent swelling. The wrist and fingers are relaxed by the use of a dorsal, padded, aluminium splint or by plaster of Paris. The hand should be elevated for forty-eight hours and prophylactic antibiotics given. A F T E R CARE

Early movements have never been shown to be helpful, and there is evidence clinically from Pulvertaft (1948) and experimentally from the work of Mason and Allen (1941), that early movements are harmful and increase the reaction at the site of the repair. The patient must be instructed on no account to attempt finger or thumb movement. Immobilisation should be continued for a total of three weeks and movements subsequently recovered by active exercises, assisted by a physiotherapist if necessary. There must be no passive stretching though gentle spring or elastic traction is often helpful to stretch adhesions and stiff joints. CRITICAL FACTORS

There is no doubt that most authorities agree that if the wound is tidy, and caused by a sharp implement and the patient seen in the first few hours after injury, primary tendon repair of the divided flexor tendon should always be considered. In general terms where the superficial tendons alone are divided at any level, the functional defect will be so slight that they are probably better left unrepaired. At whatever level tendon division occurs, if the local conditions are not favourable and skilled surgical treatment not available, it is far better that the wound should be cleaned and closed and tendon repair deferred rather than an ill-advised, primary operation performed, which may jeopardise further surgery later. The factors which militate against success are necrosis of tissue, delayed healing, and infection. Careful surgery and prophylactic antibiotics should prevent these occurring. LOCAL FACTORS

Flexor tendon division at the wrist

Above the carpal tunnel, the tendons lie loosely surrounded by paratenon. Primary repair at this level is almost always successful even when all the tendons are divided. They will frequently function independently if all are repaired but if the level of division is such that cross tendon adherence appears likely, it is per103

Primary Repair o/ the Severed Flexor Tendon--H. Bolton

missible to remove the superficial tendons to prevent this happening. If major nerve division accompanies the tendon injury, it is likewise amenable to primary repair using the same strict criteria already outlined. Isolated superficial tendon division is probably better left untreated. Flexor tendon division in the carpal tunnel At this level the tendons and median nerve are enclosed in a tight fibro-osseous tunnel. Conditions are similar to those in "no man's land", and the problem of adhesion formation is just as great. The profundus alone should be repaired and the superficial tendon removed, if the median nerve is divided primary repair can be undertaken. The isolated superficial tendon division should be left unsutured. In all operations at this level, the flexor retinaculum must not be sutured. Tendon division in the palm Primary tendon repair is usually the method of choice. The tendons lie surrounded by paratenon and the lumbrical muscles which afford material with which to separate suture lines. Both the profundus and superficial tendon can be repaired at this level and can later be shown to function independently. Tendon division in "no man's land" From the distal palmar crease to the insertion of the superficial tendons on the middle phalanx, the flexor tendons lie in a tight fibro-osseous tunnel, and when tendon division occurs in this area, it has usually been accepted that no attempts at primary repair should ever be undertaken. Standard teaching has been that the wound should be closed and a secondary repair performed at a later date. So many bad results have followed ill-advised or inexpertly performed repairs in this region that there is no doubt that this is sound practice, but in clean, incised wounds, seen in the first hours after injury when an experienced surgeon and operating theatre are available, and the patient suitable for an anaesthetic, then a primary repair can give an excellent result. It is obvious that this combination will, of necessity, make the performance of a primary repair in this region infrequent, even in the hands of those willing to undertake it. The profundus tendon only should be sutured and the superficial tendon excised, leaving one slip stretching from its insertion to just proximal to the proximal interphalangeal joint and tacked to the side of the fibrous tendon sheath to prevent subsequent hyperextension of this joint. The fibrous tendon sheath should be excised for about one quarter inch on either side of the suture line in the tendon, otherwise the tendon will adhere and gliding will not occur. The author has no experience of the technique advised by Richards (1963) in which following repair of the profundus, the tendon sheath is closed at the site of damage. In wounds in which it is found that the superficial tendon is intact, it is probably better not to repair the profundus tendon and the author agrees with Rank and Wakefield that it is wiser not to jeopardise the function of an intact superficial tendon. Tendon division distal to the proximal interphalangeal joint In suitable cases, division of the profundus tendon at this level should normally be treated by primary repair. Occasionally if the division is near the insertion, the proximal tendon can be advanced and fixed to the normal insertion by one of the accepted techniques but this is only possible if the division occurs with half-an-inch or so of the normal profundus attachment. Spontaneous recovery of flexion without repair has been reported when presumably tendon retraction has been prevented by an intact vinculum. More proximal division should be repaired by direct suture. The tendon sheath should be removed to prevent adhesion. Some surgeons have

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Primary Repair o/ the Severed Flexor Tendon--H. Bolton

attempted tendon advancement in this particular injury but the tendon arrangements at and above wrist level do not lend themselves so readily to this manoeuvre as does the flexor longus pollicis. THE THUMB

Primary tendon repair is usually very satisfactory in the thumb for there is only one tendon in the sheath and even an incomplete flexion range is often functionally adequate. According to R a n k and Wakefield (1968) the thumb also lends itself to tendon advancement by advancing the proximally cut tendon end to its insertion by lengthening the tendon at the musculo-tendinous junction just above the wrist. RESULTS

In reviewing patients in which primary repair has been performed using these criteria it was found that in nineteen fingers, the result was poor in five, and turther operation required, either tenolysis or tendon grafting. In the case of nineteen thumbs only one required further operation. The range of movement in some of the others was nowhere near normal but was functionally adequate. SUMMARY

The type of wound and the length of time since it was caused are the most important factors in deciding on the feasibility of primary flexor tendon repair. Above the wrist and in the palm, the local conditions are more conducive to a favourable result but in the carpal tunnel and in "no man's land", it is essential that the wound be suitable, the period since wounding short, and the technique of the repair satisfactory, if there is to be a successful outcome. The results in the thumb are superior to those in the fingers, immobilisation for three weeks in the relaxed position must be accompanied by firm instructions to the patient that finger movements must not be attempted. If all the circumstances are not favourable it is always safer to close the wound and leave definitive tendon repair to a later date.

REFERENCES

BOYES, J. H. (1964) Bunnell's Surgery of the Hand, 4th Edition, 594-596. Philadelphia, J. B. Lippincott Company. MADSEN, E. (1963) Primary tendon suture with delayed emergency operation. Proceedings of the Second Hand Club, London, May 1963, 2. MASON, M. L., and ALLEN, H. S. (1941) Rate of healing of tendons. Annals of Surgery, 113: 424. PULVERTAFT, R. G. (1948) Repair of tendon injuries of the hand. Annals of the Royal College of Surgeons, 3: 3. RANK, B. K., WAKEFIELD, A. R., and HUESTON, J. T. (1968) Surgery of repair as applied to hand injuries, 3rd Edition, Edinburgh and London, E. and S. Livingstone. RICHARDS, H. J. (1963) Primary, and delayed primary repair, of the flexor tendons of the fingers. Proceedings of the Second Hand Club, Birmingham, November 1963, 3. VERDAN, C. E. (1960) Primary repair of flexor tendons. Journal of Bone and Joint Surgery, 42A : 647. 105