SURGICAL EXPOSURE OF FLEXORTENDONS IN THE HAND

JULIAN M. BRUNER M.D., F.A.C.S.Des Moines, Iowa, U.S.A.

THE TERMS OF reference of this lecture are that it shall be concernedwith some subject allied to plastic surgery in which the speaker hashad experience. I have chosen to discuss the surgical exposure of flexortendons in the hand. My experience of this subject has been acquiredin army hand centres and in practice for 25 years in the capital city ofa mid-western American state where my father began his medical andsurgical practice in 1893. Injuries of the hand occur frequently here-in the home, in the factory, and on the farm.Tendon repair in general has been successful for many years. Accurate

suture of the cut tendon, with appropriate splinting to avoid dehiscenceuntil strong union occurs, is generally followed by good results.On the flexor side of the hand, however, such is not the case. The

reasons are anatomical and functional. At the base of the digits anldat the wrist tight retinacula hold the flexor tendons in their courseduring flexion. A second factor militating against successful repairis the long excursion of these tendons (2-3 in (5.1-7.6 cm)), anythingshort of which means disabilty of that finger. A third factor presentin the digit (but not in the wrist) is the tenuous and vulnerable bloodsupply available to the flexor tendons through the slender vincula.These three factors have conspired to make flexor tendon surgery inthe hand difficult. Recent improvements in technique, however, haveled to better results. Among these is the use of new incisions to gainbetter exposure.

Primary flexor tendon repair in the distal digit, in the proximalpalm, and in the forearm is generally successful; therefore this dis-cussion will be limited to the two retinacular regions where success iselusive: No Man's Land at the base of the digit and the carpal tunnelzone at the wrist.The late Dr. William J. Mayo, whom I assisted years ago, often

stressed the importance of wide abdominal exposure to view the path-ological anatomy and to perform the operation. Good exposure is even

Second part of the sixth Mclndoe Lecture delivered at the Royal College of Surgeons of

England on 7th December 1972 at the meeting of the British Association of Plastic Surgeons

(Ann. Roy. Coll. Surg. Engl. 1973, vol. 53)

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SURGICAL EXPOSURE OF FLEXOR TENDONS IN THE HAND

more pertinent in the hand, where structures are small and accessdifficult.

In 1950, on the invitation of Sir Archibald Mclndoe, I attended themeeting of the British Association of Plastic Surgeons at Hill End, St.Albans, under the presidency of Mr. Rainsford Mowlem. After themeeting I spent some time at East Grinstead and presented a shortpaper before the house staff of the Queen Victoria Hospital on thesubject of 'Incisions for non-septic surgery of the hand'. (This paperwas later read before the house staff of the Royal Infirmary, Edinburgh,at the invitation of Sir James Learmonth, one of my surgical chiefsat the Mayo Clinic, and was published in the British Journal of PlasticSurgery in 19511.) In this article I presented ideas current in 1950 re-garding surgical exposure in the hand and described the dilemma of thesurgeon who was attempting with great frustration to expose longitudinalstructures through transverse incisions, to conform with the skin creases.These limited crease incisions, although leaving fine scars, were a handi-cap in obtaining necessary exposure.

As an example of how progress was retarded, let us recall the ex-posure used for fasciectomy in Dupuytren's disease. At that time manyof us performed this operation through an incision in the distal palmarcrease supplemented by separate incisions on the finger. This meant a

difficult and obscure dissection with extensive undermining of the skin.Today fasciectomy is done through continuous digitopalmar incisionswhich give excellent exposure of the hyperplastic fascia in the regionof the joints where contracture occurs. They are often zig-zag incisions,or longitudinal incisions, converted by Z-plasty in the finger and inthe palm as suggested by McGregor.

Exposure of flexor tendons in the digitsPrimary repair. For primary repair of the flexor tendons we must

have early, clean, incised wounds, commonly seen after lacerationscaused by broken glass and sharp metal. The surgeon presented withsuch a wound on the volar surface of the finger must decide how bestto obtain additional exposure for local resection of the digital theca,tendon repair, and nerve suture.

In oblique wounds additional exposure is obtained by proximaland distal bayonet extensions just anterior to the neurovascular bundle.Transverse wounds on the finger pose a greater problem. These also maybe extended by bayonet incisions, but if one digital artery has beensevered or thrombosed, the distal extension must be on the same sideas the injured artery or a skin slough may occur. Transverse woundsof the finger should not be enlarged by zig-zag extensions immediately

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JULIAN M. BRUNER

adjacent to the wound of injury. To do so creates skin flaps with acuteangles, and skin necrosis may occur if blood supply is compromised.

If both neurovascular bundles are severed, both nerves and one ar-tery should be sutured if possible. In such a finger tendon repairshould then be deferred for later grafting.

Fi-. 1. Extension of wounds for primary flexor tendon repair.

Elective surgery. For elective surgery the Bunnell mid-lateral in-cision has been standard. The volar digital skin remains intact, and theincision heals with an acceptable scar. However, this lateral approachleaves much to be desired, because: (1) the dorsal branches of thedigital nerve must be severed, or they remain in the way; (2) the lateral

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SURGICAL EXPOSURE OF FLEXOR TENDONS IN THE HAND

approach to the flexor tendon may injure the collateral and retinacularligaments; (3) if the incision is extended into the palm it must cross theneurovascular bundle; and (4) it is awkward to work between fingersor on the ulnar side of the thumb.

In 1965 I departed from the traditional mid-lateral approach andmoved to the volar skin. This was prompted by an accidental zig-zagglass cut on the finger of a young student sustained while bar-tending.The exposure provided by this ready-made incision was so good, theresult of primary tendon repair in No Man's Land so successful, andthe subsequent scar so favourable that I decided to use this staggeredapproach for other flexor tendon repairs. Such a volar approach isdirect, does not encroach on the neurovascular bundle, and may be ex-tended into the palm as far as necessary. The digital theca is therebywidely exposed so that it can be partially excised (for either primaryrepair or tendon grafting), leaving whatever pulleys are necessary in thefinger to prevent bow-stringing of the tendon or graft.

In 1967 I reported the use of this incision at the Anglo-ScandinavianSymposium of Hand Surgery in Lausanne and Vienna2. Three yearslater at the joint meeting of the American and Scandinavian Hand So-cieties in Finland, Sweden, and Holland I was pleased to find that thismethod of exposure of the flexor tendons was frequently being usedby surgeons in those countries.There has been some difference of opinion as to the exact delinea-

tion of the volar zig-zag incision. All agree that the hinges should beat the skin creases of the finger and palm. However, some haveplaced the hinge in the mid-lateral line of the finger. I believe that theincision should extend only to a point directly anterior to the neuro-vascular bundle and should not encroach upon or even expose it, thusinviting injury. The angle at the hinge should be somewhat less than135 degrees. Some surgeons have doubled the number of zig-zags ineach finger segment, reducing the angle to about 90 degrees, thus mak-ing the skin serrations sharper. In the distal segment of the finger orthumb the incision should skirt the proximal edge of the digital nerve asit fans out to supply the pulp, thus leaving intact sensation in the fingerpad. At the end of the incision, just proximal to the vortex of thefinger print, direct access is given to the insertion of the profundustendon-especially important in tendon grafting. Proximally the zig-zagcourse may be extended into the palm and to the thenar crease; thenceto the wrist if necessary.Two other American surgeons were pioneers in the use of this in-

cision: Dr. J. W. Littler of New York and Dr. L. D. Howard of SanFrancisco. The latter once remarked: 'The volar zig-zag incision onthe finger just had to come.'

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In my experience, scars resulting from this incision have been ac-ceptable and no changes in sensation of the volar digital skin havebeen noted. Flexion contractures have not resulted. If they occur, theymay be due to injury of the volar plate or to improper postoperativesplinting. The little finger especially has a strong tendency to curl up,shrimp-like, at its interphalangeal joints. This must be prevented bysplinting these joints in extension as recommended by J. I. P. James.

Exposure of flexor tendons at the wristWe turn now to the exposure of flexor tendons at the wrist. Their

repair in the carpal tunnel zone has often been attended with difficulty,as it has in No Man's Land. The carpal canal, containing nine flexortendons and the median nerve, is normally snug, and when swellingoccurs in the synovial tissues, as it frequently does in menopausalwomen, pressure is exerted on the median nerve, with resultingparaesthesiae.

Decompression of the median nerve for 'carpal tunnel syndrome' wasfirst done by James Learmonth in 1930 at the Mayo Clinic on a patientwith arthritis of the wrist. He used a short transverse incision throughwhich he divided the transverse carpal ligament, with dramatic relief ofsymptoms. It was not until about 1950, however, that this operationcame into general use. We have since learnt that wider exposureof the carpal canal is advisable to avoid injury to the median nerveand its motor and sensory branches. The incision commonly used islongitudinal, with a small zig-zag at the wrist level to minimize the scar.

In my experience, section of the volar retinaculum has been withoutcomplication. Bow-stringing of the flexor tendons does not follow as itdoes on the back of the wrist when the dorsal retinaculum is severed.If one explores this region one or two years later, he finds that thetransverse carpal ligament has been reconstituted.Such wide exposure has not yet been exploited for the repair of ten-

dons injured within or near the carpal canal. Many surgeons still regardthe flexor retinaculum with some awe and go to great lengths not tosever it. The transverse carpal ligament is a bridge under which theflexor tendons ebb and flow, but like the Tower Bridge in London itmay be opened, and in due course it will close itself (Fig. 2).

Primary repair. During the past five years I have opened the carpalcanal widely for the primary repair of tendon injuries. The transversecarpal ligament is transected, distally the palmar fascia is incised, andproximally the antebrachial fascia is freely divided. With such wide ex-posure, multiple tendons severed within or near the canal may be quicklyidentified, matched, and repaired, also the median nerve if it is injured.

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SURGICAL EXPOSURE OF FLEXOR TENDONS IN THE HAND

The antebrachial fascia and the transverse carpal ligament should neverbe sutured. The palmar fascia should be excised locally in the regionof tendon suture to prevent adhesions (Potenza).A word of warning! Oblique wounds on the volar surface of the

wrist may usually be connected with the standard carpal tunnel incision,

Fig. 2. Surgical exposure of flexor tendons.

but with transverse wounds of the wrist a cruciate incision must beavoided, or sloughs may occur in the distal flaps. If there is any ques-tion of adequate blood supply, a bridge of intact skin should be leftjust distal to the transverse wrist wound under which the transversecarpal ligament may be incised (Fig. 1).

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In many textbooks the surgeon is advised to suture only the pro-fundus flexor tendons if all are cut under or near the transverse carpalligament. I believe the sacrifice of the sublimis tendons, so indispensablefor individual flexion of the fingers, is destructive and unnecessary. Forsome time now, with wide exposure of the carpal canal, I have re-paired all flexor tendons cut within or adjacent to it, both profundusand sublimis. They heal well and adhesions that occur are graduallymobilized by individual finger motions. Cross-union of profundus andsublimis flexor tendons has not been a problem in my experience. Ifsuch union should persist, tenolysis is available.

Elective surgery. Incisions for elective surgery at the wrist level areoften limited to short transverse or L-shaped incisions proximal to thetransverse carpal ligament. These will suffice for elective surgery on oneor two tendons. If many tendons are involved, the standard carpal tUIl-nel incision may be necessary.

DiscussionMuch experimental work has been done in recent years in regard to

the blood supply of the cut tendon and the mechanism of healing. Weknow that a callus of fibroblastic tissue occurs at the site of suture andthat healing comes largely from peripheral cells in the wound and notfrom the cut ends of the tendon.

After a flexor tendon is cut in the finger it is often prevented fromretracting by the vincula, in which fine blood vessels are then subjectedto strong muscle traction for hours or days, with possible thrombosis.If this happens, a segment of the sutured tendon may actually be an

infarct. The tissue reaction to a segment of dead tendon must be in-tense, and this may explain many a failure after primary repair. It isin such cases that we return to the scene months later to do a tendongraft and will find a congealed conglomerate of cicatrix.

In the Bunnell Lecture of 1971 Claude Verdans reviewed the presentstatus of flexor tendon surgery in the hand, including both primary re-

pair and grafting. He believes that when both flexor tendons are cut

in No Man's Land removal of the sublimis tendon, which has beenstandard practice for many years, may injure the blood supply of the

profundus tendon. He reports cases in which he has sutured both sub-

limis and profundus tendons in No Man's Land with excellent results.

My experience in the carpal tunnel zone is similar to Verdan's in No

Man's Land-that is, the sublimis tendons may be successfully retained

and repaired. This suggests that a technique practised for many yearsneeds to be reexamined. It may be that in the future the sacrifice of

the sublimis tendon in both areas will be remembered as an ancientpagan rite still practised by hand surgeons in 1972.

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SURGICAL EXPOSURE OF FLEXOR TENDONS IN THE HAND

(a) ..... :< : . .: . : ~~~~(c)Fig. 3. Tendon graft, both flexors little finger (4 months post-injury).(a) Preoperative. (b) Zigzag volar incision. (c) P.L. graft in place (d) Post

operative-hand open. (e) Postoperative-hand closed.

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(b)

JULIAN M. BRUNER

ConclusionDuring the past 25 years flexor tendon repair in the hand has made

significant advances. Flexor tendon grafting has been brought to ahighly successful level, as evidenced by the admirable series reportedby Guy Pulvertaft4 and by Joseph Boyes. Primary repair, so long inthe doldrums but so advantageous to the patient, now shows greatpromise. More successful primary repairs are now being done andthe status of briefly delayed primary repair is being defined.Improved techniques are contributing to these advances. Among these

are incisions which give better exposure. Although some surgeons mayregard the serious discussion of incisions as elementary, such is not thecase in the hand. The correct incision, indelibly inscribed on the skin,is a plan of battle. It may portend victory or defeat from a skin slough,or condemn the surgeon to a two-hour arduous repair which might havebeen completed in one hour. Unfortunately many incorrect incisions aredepicted in textbooks and the error perpetuated through several editions.Examples of this are misleading incisions recommended for the reliefof carpal tunnel syndrome or de Quervain's disease which expose sen-sory nerves to injury, often with serious disability.The volar zig-zag incision, previously proscribed but used now for

more than five years by many surgeons, is a dependable alternativeto the standard mid-lateral digital incision and greatly facilitates electiveflexor tendon surgery. The carpal tunnel incision, until recently usedonly to decompress the median nerve, is now being exploited for therapid primary repair of multiple tendons sevefed at the wrist.

Finally, if we are to make real progress in flexor tendon surgery,the surgeon who does primary repair and the surgeon who does ten-don grafting must actually be one and the the same person.

The future of hand surgery. And what of hand surgery in the fu-ture? Today in Britain and in America it is being done by plastic,orthopaedic, and general surgeons. In this context it is a subspecialty,but it may not remain so.

The scope of hand surgery is expanding. Surgery for rheumatoiddisease of the hand is an important branch, developed during recentyears. My colleague in Iowa City, Adrian Flatt, is one of several sur-

geons well qualified in this field who are mercifully correcting thedeformities of these crippled hands.

Microsurgery applied to the repair of small arteries and nerves is an-

other recent development, and it appears likely that hand surgeons ofthe future must be skilled in the use of the operating microscope. Theaccomplishments of Cobbett of East Grinstead, O'Brien of Melbourne,and James W. Smith of New York are impressive.

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SURGICAL EXPOSURE OF FLEXOR TENDONS IN THE HAND

(a)

Fig. 4. Primary repair, both flexors little~~~~~~~~~~~~~~~~finger..(a)Peerte.. (b)Fin

gretd . (c) Finr f2 0$ ,R 'i ~(b)

( c )~~~~~~~~~~~~~~~~~~CFig. 4. Primary repair, both flexors little finger. (a) Preoperative. (b) Fin-

gers extended. (c) Fingers flexed.

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JULIAN M. BRUNER

As trauma increases in modem life, traumatic hand surgery expands,requiring expertise in bone, nerve, and tendon repair. This suggeststhat hand surgery should be a specialty in its own right. A few surgeonslocated in the large cities of America confine themselves to surgery ofthe hand, and a good case can be made for such limitation. If one visitsthe clinics of these surgeons, he will at once appreciate the high levelof their clinical judgement and technical skill. It is likely, however,that for some years ahead hand surgery will remain a subspecialty.The chief problem is to develop training centres and to determine thescope and length of such training.The study of anatomy, now lamentably de-emphasized in some med-

ical schools and postgraduate programmes, must on the contrary, bereinforced by repeated dissections. The Royal College of Surgeons ofEngland and its sister Colleges have traditionally fostered the higheststandards of anatomical knowledge. This must be maintained especiallyin surgery of the hand, where the precise knowledge of normal and an-omalous structures is of critical importance.The desire of surgeons to avoid scars on the volar surface of the

fingers, hand, and wrist is commendable, but experience has shownthat exposure of the flexor tendons through crease incisions is in-adequate. Poor flexor tendon surgery is often the direct result of poorexposure. The function of grasp is by far the most important in thehand and far outweighs cosmetic considerations. However, if rea-sonable care is used in the closure of zig-zag incisions, they areinconspicuous, as shown by the photos in Figures 3 and 4.

In the United States 54 centres for training in surgery of the handhave been listed in a brochure issued by the American Society for Sur-gery of the Hand. However, these centres have no official approval andthe training period has not been agreed upon. I believe it should includeat least one year of experience on a service where large numbers of handcases are seen.At the meeting of the British Society for Surgery of the Hand ill

Windsor in May 1972 steps were taken for the development of suchcentres in Great Britain. The high level of hand surgery in this countryis known throughout the world and is due in no small measure to thework of those pioneers in this field of whom Sir Archibald Mclndoe isan outstanding example.

REFERENCES1. BRUNER, J. M. (1951) British Journal of Plastic Surgery, 4, 48.2. BRUNER, J. M. (1967) Plastic and Reconstructive Surgery, 40, 571.3. VERDAN, C. (1972) Journal ofBone and Joint Surgery, 54-A, 472.4. PULVERTAFT, R. G., Personal communication.

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