Frontiers in Hand Rehabilitation 0749-0712/91 $0.00 + . 20

melano-~ripheral

:~e kinase ’:mration. Recurrent Carpal Tunnel Syndrome,

~tored Epineural Fibrous Fixation, andto nerve

Tractionree,l DP: ~europamy

f internalrepair in

~6 James M. Hunter, MD*~: Nenro-~ebe GW~shington,

"~9uests to

hell, MD I The surgical release of the transverse carpal re, suits rarely became evaluated. Reports have

~: Surgeryi

ligament for the uncomplicated carpal tunnel been documented that deal with the weaknessmsylvania ~ syndrome (CTS) can be acceptable for hands of pinch and grip after carpal tunnel ligamenttee Street not requiring heavy, repetitive, complex or division. Hence, some hand surgeons have beenPA 19104 sophisticated work. Articles appear weekly in concerned with the need to close the carpal

the popular press concerning carpal tunnel syn- ligament after repair. These techniques, i.e.,drome; for example, "if you have numb fingers Z- or N-plastics, are usually loose closures that

iat night or in the morning, don’t suffer, call ensure ample room in the canal for the medianyour doctor and have the miracle operation, nerve. This plan enhances pinch, not grip,

~ why suffer any longer." A recent article by s~rength.Raoul Tubiana7, author of four volumes of hand Recurrent carpal tunnel syndrome is becom-surgery, states that "despite its high incidence ing a real problem in increasing numbers, andand its reputation for simplicity and efficiency, numerous complications are also increasing~ Icarpal tunnel release does not invariably pro- am particularly concerned about the number ofduce good results, and dissatisfied patients are patients with CTS that do not return to thenot infrequently, encountered." Unsatisfactory work force after surgery. Their complaints ofresults are caused by inaccurate diagnosis and, pain in the hand and weakness of grip are often

i : all too frequently, iatrogenic surgical complica- passed off as "compensationitis."tions. Surgical technique plays an important This article addresses certain factors that re-

; role in the achievement of good results, late to less than optimum surgical results afterThe diagnosis of CTS frequently requires only carpal tunnel surgery and after recurrent carpal

~ : a complaint of numb fingers before surgery is tunnel surgery, Some of the patients have hadi contemplated. The surgical treatment of CTS is previous injuries, others multiple neuropathies

now undertaken by any surgeon capable of or repeated surgeries; function is reduced andoperating. There is no gold standard left to morale is low.balance the scale to good or excellent results. A new treatment plan proposes that completeInstead, acceptable and unacceptable is the :median nerve mobilization p~rmits anatomic

-i:? margin for approval, surgical closure of the carpal ligament to pre-Looking over 20 years of carpal tunnel sur- serve the full function of grip and pinch.

gery in a large hand center practice, I have A therapy "solution" to the carpal tunnelcome to appreciate that if the patient had cor- recovery problem is the idea of a quick, intenserection of numbness and tingling in the hand work-hardening program. Those experienced, inand no complications, that would be considered hand surgery and hand therapy know full wella good result. The complicated cases were al- that as part of a progressive program, the con-

..... ways placed in another category of recovery, so cept of preparing a patient for work is sound in

*Distinguished Professor of Orthopaedic Surgery, Jefferson Medical College, Thomas Jefferson University; President, HandRehabilitation Center; President, Hand tlehabilitation Foundation, Philadelphia, Pennsylvania

Hand Clinics--Vol. 7, No. 3, August 1991 491

492 James M. Hunter

philosophy and results. A revie~v of cases thathave failed to make the grade shows that therehas been very little information documented asto where the patient was before the decisionfor surgery was made and carried out. Forexample, how many months did it take for himto get to a point where he couldn’t work prop-erly and, in fact, did he have any history of pastinjuries to the hand or the extremity? If so, hadhe ever fully recovered? In fact, was the patientcompensating for problems by substituting su-pination and pronation of the forearm, and eveninternal and external rotation of the arm, beforehe finally was unable to carry on any longer?This situation promotes disuse atrophy, imbal-ances of function, and other neuropathies thatoverall are going to require a carefully plannedtime period after surgery to give optimum func-tion to the upper extremity. The miracle ofcarpal tunnel surgery falls short, as does post-operative ~vork-hardening programs in patientswho fall into these categories.

Many patients are made worse by rapid-pacerecovery programs: supination activities are un-comfortable because they put the median nerveon traction, so the patient compensates withpronation, only to develop a radial neuropathy.Depending on the demands of the work per-formance, this unfortunate patient, now with adouble neuropathy, may find the only way outis to use arm motions and shoulder and necksubstitutions to perform supination and prona-tion and forearm activities with the arm ininternal and external rotations. This, of course,is the step toward the "brachial plexus tractionproblem" that may go unrecognized for longperiods. The complex pattern of the multiplerieuropathies is not uncommon today and,therefore, must be looked for carefully in the.future by physicians and therapists. The multi-ple neuropathy problem in the upper extremitymust be carefully reviewed in all patients whocomplain of an unsatisfactory and incompleteresult following carpal tunnel syndrome sur-gery.

Over the years, it has been interesting to meto have been asked many times, "Dr. Hunter,when you place those tendon rods, don’t youever get a carpal tunnel syndrome?" In over700 staged tendon surgeries, approximately 200multiple rods have been placed in the carpaltunnel, and I have not been able to observe atrue compression neuropathy of the mediannerve, because the space in the" carpal canalcan handle as many as four tendon rods. Theroutine technique in our hand service for manyyears has been to pass a large curved Kelly

hemostat through the ulnar side of the carpalcanal, press the instrument next to the hamate,and transect the carpal ligament. If one ap-proaches the canal from the proper angle andmoves along either the superficial or deep levelo:~ the flexor tendons, large instruments movev.ery easily, and it is possible to put two andthree Kelly hemostats in the space of the carpalcanal.

We should be thinking differently about thenarrow compartments that permit the "com-pression neuropathy’" of the median nerve. Inother words, there is, except in the situation oftumors, displacement of carpal bones, or syno-vitis, plenty of room in the bony carpal canalfor the nine flexor tendons, their sheaths, andthe median nerve. There must, therefore, beother factors present. Why then does not theroutine carpal tunnel surgery correct the prob-lem uniformly? Why do many patients complainof hand weakness, and why are some patientsworse after carpal tunnel surgery?

Clinical records and data are being collectedat our hand center on the demography of over1,000 eases of carpal tunnel surgery. There is astrong suggestion that some 20% did not per-form as expected. I have termed these "recur-rent carpal tunnel syndromes.’" Our studiesshow that there is a high incidence of previousinjury in recurrent carpal tunnel syndrome. Itmoves some 27% in the general population to46% of patients studied with recurrent carpaltunnel syndrome. These findings suggest thatsomething different happens to these patientsto take them out of the simple category of a__compression neuropathy of the median nerve.As surgeons, we should consider this group ofpatients with previous injury to the hand orwrist very carefully. This group of patients mayhave fibrous fixations or neurbdesis to the epi-neural nerve structures (Fig. 1). With glidinglimited, traction neuropathies develop withwrist, hand, and forearm motion. The time ofonset and the intensity of symptoms vary,, andmay be intermittent. Electromyographs (EMGs)are frequently normal. The examining physicianmust apply techniques of traction stress to thenerve, and the electromyographer must do thesame (see the article in this issue by RichardRead).

As centers become more adept at diagnosingthe neurologie thoracic outlet syndrome, or asDr. Schwartzman describes it in this issue’s"The Brachial Plexus Traction Injury," it willbe apparent that there is a high incidence ofthis problem existing with CTS, with an in-

carpal~amate,,he ap-;le and.’p levels move,vo and,~ carpal

out the

rve. Ination of~r syno-~I canalhs, andbre, benot thee prob-)mplainpatients

)tleetedof over

ere is a~ot per-"recur-studies

~reviousome. Itation tot carpalest thatf)atients~ry of a

nerve.;roup ofland ornts may:he epi-gliding

,p withtime of!ry, and(EMGs)wsieian,; to the~ do thelliehard

~nosing(:, or as

issue’sit will

ence ofan" in-

Recurrent Carpal Tunnel Syndrome, Epineural JVibrous Fixation, and Traction Neuropathy 493

Figure i. Traction neuropathy of the median nerves in the forearm. The patient originally sustained a contusion of the "forearm at work. Scar fixation of the median nerve was proximal to the site of two wrist surgeries. This is finally recognizedat the third surgery.. A, On the left of the illustration, note the smooth sheath surface of nerve gliding following surgeD, IIwith wrist motion. In the center, note epineural sear fixation of the median nerve at the site of original injury, occurringtwo years earlier. On the right, observe a proximal forearm traction neuropathy of the median nerve. The nerve is thin,and the surface is fibrous (the thumb abduction stress test positive in 30 seconds). B, Median nerve free from sear; glidingsheath on nerve surface distal; fibrous sheath on traction nerve proximal. This patient disabled by pain in the hand andforearm became progressively worse in therapy. Traction neuropathy of the median nerve caused the hand to be used inpronation resulting in radial neuropathy.

creased incidence in recurrent carpal tunnelsyndrome.

BEHIND THE SCENES IN CARPALTUNNEL SYNDROME: PROBLEMS THAT

MAY BRING ON RECURRENT CARPALTUNNEL SYNDROME

Previous injury to the hand and wrist mayalter the anatomy and physiology of the mediannerve by local or general fibrous fixation tosurrounding tissues (the fibrous fix or neuro-desis). When this is unrecognized at the timeof carpal tunnel surgery, nerve fixation maybecome more severe, and new pathology maydevelop; hence the recurrent carpal tunnel syn-drome..~ Unrecognized secondary neuropathy in the

forearm from misuse or overuse is also a factor;for example, the radial neuropathy and theulnar neuropathy.

Another problem is the unrecognized bra-chial plexus neuropathy or traction injury sec-ondary to (1) work problems, especially lateralabduction or overhead lifting, that (2) falls the outstretched arms and, for the 80s and 90s,(3) high-velocity vehicle injury and the com-puter keyboard.

The most common behind-the-scenes prob-lem in CTS is nerve fixation that has occurredin the trail of life. For example, the forgotteninjury when young, falling from a’skateboard,

the armed service injury, the sprained wrist,which is passed off and now forgotten; the caraccident, perhaps many years ago, ~vhen thehand hyperextended on the dashboard; the fallon ice with a sprained wrist or possible fracture.These are examples of occasions where tensionor traction of the median nerve may haveoccurred. Injury followed by repair graduallymatures into fibrous changes in the epineuralstructures of the nerve and in the epineuralstructures around the nerve. Fibrous sheets orspecific scar fixations can form anywhere alongthe nerve and block the ability of the nerve tobe elastic and reform as joint and tendons moveand contract.

One of the most common findings in seriesof carpal tunnel syndromes is the pattern forthe median nerve to be fixed toward the volarsurface and to the radial side of the carpal canal(Figs. 2 and 3). This is a position that createsample room for the passage of the flexor tendonsduring the transmission of power grip in thehand with the wrist movement. The radialposition of the median nerve presents the mostadvantageous position :for the nerve to managethenar motor innervation as well as thumb,index, and middle finger innervation.

Importantly, this type of pre-existing fibrousfixation surrounding the epineural surface ofthe median nerve is functional until stressedwith excessive work traction or a new injury.Dr. George Phalen, in his classic article oncarpal tunnel syndrome~ noted that the com-

1 extensor carpi ulnaris2 triquetrum3 flexor digitorum profundus4 pisiform5 flexor carpi ulnaris "6 ulnar nerve7 volar carpal ligament8 ulnar artery and venae comitantes9 palmaris Iongus

10 flexor digitorum superficiatis11 median nerve and palmar cutaneous

branch12 flexor retinaculum13 flexor pollicis Iongus14 flexor carpi radialis15 abductor pollicis Iongus16 extensor pollicis brevis!7 radial artery, and vena~ c.omitante.~18 superficial branch of radial nerve19 scaphoid20 extensor carpi radialis Iongus21 extensor carpi radialis brevis22 capitate23 extensor pollicis Iongus24 posterior interosseous nerve25 extensor digitorum communis and

extensor indicis proprius26 hamate27 extensor digiti minimi

14 1312 1109

24

8 76

25 26 27

Figure 2. Cross-section anatomy of wrist. Note #11 median uerve and iucisioo site. (From Tubiana R, McCnllough CJ,Masquelet AC:..A,n Atlas of Surgical Exposures of the Upper Extremity, Loudou, Martio l)uoitz, 1990, p 249; withpermission.)

Recurrent Carpal Tunnel Syndrome, Epineural Fibrous Fixation, and Traction Neuropathy 495

3

2

1 deep head of flexor pollicis brevis2 oblique head ~ adductor pollicis3 transverse head4 first dorsal interosseous5 interossei6 deep motor branch of ulnar nerve

Figure 3. Anatomy of hand: Flexor tendons beneath major retinaculum of hand. . (From Tubiana R, McCullough CJ,Masquelet AC: An Atlas of Surgical Exposures of the Upper Extremity. London, Martin Dunitz, 1990, p 263; withpermission.)

pression neuropathy with hourglass effect ~vasthe prevalent finding at surgery. After surgery,patients went through uneventful recovery andminimal complications after this carpal tunnelrelease. Phalen believed that, diagnostically,the wrist flexion test was due to a swelling ofthd median nerve at the proximal edge of thetransverse carpal ligament. Eighty percent ofhis cases had positive flexion tests. The wristextension test was not mentioned as aggravatingthe symptoms of CTS. There is no referenceprior to surgery of cumulative trauma. A reviewof our series of cases in 1990 suggests that thedemography of patients with CTS has changed.Some of the complaints are similar, particularlythe numbness at night and in the mornings.The pain and burning paresthesias, weaknessesand disuse that seem to follow work adjustment

" neuropathies of the extremities are not dis-cussed.

¯ The hyperextension wrist and finger test, notreferred to in Phalen’s discussion, has becomea most useful test, indicating the prbbability ofa traction neuropathy or scar fixation of the

nerve along the course from palm to wrist tot~orearm.

The traction neuropathy of the median nerve:may present symptoms that coexist ~vith com-pression neuropathies, but if they can be sin-gled out: an additional problem to compressionis suggested: that of underlying traction neurop-athy. Importantly, traction neuropathy may ex-ist in the background while compression neu-ropathy is treated by carpal tunnel release.Traction neuropathy symptoms related to fixa-tion of the nerve slowly continue to presentsymptoms of weakness and, finally, pain. Theylead to recurrent carpal tunnel syndrome.

An additional test that may assist should--bediscussed: the thenar muscle abduction test isoften positive with a traction median nerveneuropathy. The technique is as follows: if theforearm is supinated, the wrist and fingers areextended and the thumb is adducted to theside. The patient must be instructed to keepthe flexor pollicis longus tendon at rest. Priorto starting this test, the abduction is reviewed.The size of the thenar muscle is identified and,

496 James M. Hunter

using thumb pressure against the thumb, astrength measurement is made from 0 to 4 +.Timing of this test starts when all three factorsare in place: the wrist extended, fingers ex-tended, and the thumb adducted, all undertension by the observer. The results should bepositive in approximately 1 minute. The patientmay complain to some extent during the test.If the nerve is very sensitive, the observer mayhave to adjust tension during the test. The finalobservation is after 30 seconds or 1 minute: adrop in the power of the thenar muscle as thepatient attempts to raise the thumb against theobserver’s thumb. The thumb fails or falls tothe side, i.e., pretest observation of 3+ maydrop to 1+ as the thumb is tested with thewrist in neutral.

This test can be duplicated in the operatingroom, with direct stimulation of the motorbranch of the median nerve, and can be usedas a motor stretch test during EMG. Scarfixation and traction neuropathy of the mediannerve are important behind-the-scene prohlemsin CTS that may lead to less than satisfactoryresults.

Behind the scenes of recurrent carpal tunnelsyndromes are congenital variations and anom-alies of the median nerve tendons and musclesin the carpal canal. I have often had the privi-lege of teaching hand fellows about the problemof the small incision, because the congenitalpattern is observed through a large generousincision. It becomes clear as a new nerve pat-tern is observed how easy it would be to haveinjured a segment of the nerve, if one was notable to see clearly and widely the operativefield (Fig. 4). There is little wonder that thereare iatrogenic nerve problems with small inci-sion release of the carpal ligament.

Figure 4. Many anomalies or anatomy variations arerelated to the median nerve in the carpal tunnel. Thisexample shows a large palmaris longus tendQn in the carpalcanal, fixed to the epineurium of the median nerve. Thiscould be a hazard with a small incision.

To elaborate on the problem of nerve fixationand traction neuropathy, the statistics from re-view of a large number of recurrent carpaltunnel syndromes show that the percentage ofpatients with previous injury in the generaldemography of patients is approximately 27%.This rises to approximately 46% in patients withrecurrent carpal tunnel syndrome; this suggeststhat nerve fixation sites are predictably presentand should be studied at every setting of carpaltunnel surgery (Fig. 5). The pattern of fixationof the nerve to the radial side of the carpaltunnel usually shows intimate attachment to thethickened flexor synovium of the flexor pollicislongus, the flexor profundus of the index finger,and the lumbrical muscle surface of the indexfinger (Fig. 5C). It is not unusual to find thenerve fibrous fixed as it curves to,yard the palmin relation to the palmar fascia, ~vhere it is ledinto the intertendinous spaces. Spinner6 haspointed out the importance of freeing the nerveat this level in carpal tunnel surgery. Thesensory nerve to the middle and ring fingersusually is well separated, working freely withspreading of the fingers and thumb. Fixation ofthe radial side of the median nerve as it passesjust distal to the transverse carpal figament tothe palmar fascia and through the preosseousbands is frequently seen at the time of surgery(Fig. 5D). Studies on 40 consecutive carpaltunnel surgeries show, after the transverse car-pal ligament has been divided, that if one holdsthe wrist at neutral and pulls on the fibrousepineurium of the nerve with an instrumentfrom distal to proximal, 2 to 6 mm of motion isgenerally the rule. Distal movement from theforearm to the carpus is 8 to 12 mm before_nerve mobilization (Table 1). These ranges aresimilar to Wilgus and Murphys prior to mobi-lization. This reflects fixation distal in the carpalcanal and looser fixation proximally, a fairlyconsistent finding in primary and recurrentcarpal tunnel surgery.

The normal anatomy of the uninjured handis one of a splay of the sensory nerves of themedian nerve in the palm (Fig. 5D). This easilypermits the thumb and the fingers to spreadwithout discomfort in the hand. This would becritical in the functions of the pianist or theviolinist. This splay effect is lost following injuryand fibrous adhesions. With fixation such asthis, when the wrist is placed in full extensionand thumb and finger extension are added atthe same time, there is essentially no movementof the nerve, because it is tractioned againstthe carpal bones like a bow string. This patternmay be reversed by pronation of the forearm

aerve fixationstics from re-arrent carpalpercentage of

the generalimately 27%.patients withthis suggests

~tably present:ring of carpal,rn of fixation)f the carpal,’hment to theflexor pollicisindex finger,of the index

tl to find the,ard the pahnhere it is ledSpinnera hasing the nerve:urgery. The

ring fingersg freely with~. Fixation ofe as it passest ligament to~ preosseous~e of surgery:utive carpalmsverse ear-: if one holds

the fibroust instrumentof motion ismt from themm before

e ranges areior to mobi-in the earpal.lly, a fairlyd recurrent

ajured hand~rves of the¯ This easily¯ s to spreadis would bemist or the~wing injuryion such as11 extension:e added at) movementned against[’his pattern:he forearm

Recurrent Carpal Tunnel Syndrome, Epine, ural Fibrous Fixation, and Traction Neuropathy 497

Figure 5. A. Incision for carpal tunnel surgery. B. Kelly hemostat under transverse carpal ligament. Pressed to hamatebone. C, Mobilization of median nerve proximal and distal to motor branch marked. D, Nerve mobilization_ of sensorymotor "’splay" in palm opened. E, Nerve mobilization: Anteroposterior lift; wrist at 20 degrees of flexion. F, Nervemobilization: Anteroposterior lift: wrist in neutral. G, Nerve mobilization: Anteroposterior lift; wrist in 60 degrees ofextension.

and by flexion of the wrist. The traction effectmay be further enhanced by flexor tendon syn-ovial fixation on the dorsal surface of the mediannerve. The adherence of the flexor tendonsynovium to the epineurium of the median

nerve (_Fig. 6) can preset the nerve with tension;extension of the wrist produces traction on thenerve. Repeated use at the workplace nowproduces numbness and weakness, followed bypain and cramping.

498 James M. ttunter

Table 1. Longitudinal and Anteroposterior Motionof the Median Nerve at the Wrist: Before and After

Mobilization Procedures

PREMOBILIZATION POSTMOBILIZATION

Wrist Neutral Wrist Neutral

P D 8 to i2 mm 10 to 22 mm13P2to6mm 6to 12mmAngular lift 20 mm 46 mm (40 to 50 ram)

Wrist Extended Wrist Extended + Fingerand Thumb 15 mm

Angular Lift 10 mm Wrist Flexed 50 to 60 mmAngular Lift i5 to 20 mm

P, proximal; D, distal; P D, forcep at proximal edge ofcanal pulls epineurium distal; D P, forcep at hamate pullsepineurium distal to proximal.

Database, 40 cases.Gliding and anteroposterior angle measured at the prox-

imal edge of the hamate. (The carpal ligament has beenopened close to the hamate.)

The lateral fibrous sheets fixed to the proximal ~vall ofthe carpal canal are opened around the circumference ofthe median nerve sufficient to pass a rubber vessel loop tolift the nerve volarly for anteroposterior measurement.

The diagnosis now is "Traction Neuropathy,"and comes on slowly with use of the hand. Thisis a more complex problem than compressionneuropathy. Patient complaints begin to include"nay hand hurts," "I have pain on use" and, attimes, "I have burning in my fingertips." Phal-en’s test diminishes, Tinel’s test at the wristincreases with wrist extension, and the mediannerve now becomes tender in the carpal canaland in the volar forearm. Many of these pat!entsare happy to rest their forearms in pronationwith the palm down. The tension-sensitive me-dian nerve, when tractioned during forearmsupination, becomes uncomfortable. These un-diagnosed patients will regress in a hand ther-apy program. They are also set up to develop aradial neuropathy from using the forearm inprotective pronation.

Figure 6. Adherence of the flexor tendon, synovium tothe median nerve.

The diagnosis of traction neuropathy of themedian nerve may be subtle and difficult todiagnosis. Stress nerve conduction electro-myography will help make the diagnosis. Theroutine EMG is usually normal, but becomespositive after putty exercise and positional stresstesting (see the article in this issue by RichardRead). This is a frequent behind-the-scenesproblem in recurrent carpal tunnel syndrome.

When the diagnosis of traction neuropathy issuspected, the approach to therapy and surgicalmanagement must be revised and new treat-ment instituted. Patients with significant nervefixation or traction neuropathy problems areunlikely to respond to routine carpal tunnelsurgery. I am troubled by the term neurolysis,often used in manv variations from one surgeonto another. Frequently heard comments relatedto neurolysis include "it is inappropriate to freethe median nerve completely at the level of thecarpal tunnel, and one should always leave thefibrous structure around the nerve or on thefloor of the nerve, for this carries the importantblood supply to the nerve." My personal obser-vation is that the median nerve, in t~aet, handlesmobilization from the sensory, nerve splay inthe palm through the carpal canal to the fascia

Table 2. Vascular Recovery of Median Nerve atCarpal Tunnel, Following Complete Nerve

Mobilization

Cases studied: Grade I --Uncomplicated carpal tunnelhistory.

Grade II --Complicated by previousinjury to hand or wrist ortraction injury and thoracicoutlet syndrome

Grade III--Complicated by previousfailed surgery at carpaltunnel

Mobilization of median nerve with (a minimum of 40 mmangular lift at the proximal hamate)

and

Vascular recovery after " /tourmquet release

Tourniquet time = average, 55 to 75 min

Recovery average

Grade I --Immediate to 15 secondsGrade II ---5 to 30 seconds averageGrade III--Variation with significant -

epineural scar fixationrequiring epineurolysis 30secto2 + min

Vascular recovery data recorded at end of operativeprocedure under 3.5 power loops. Observation based onvisible median nerve segment usually from sensory splayin palm to 1 inch proximal to wrist crease.

Pink shading throughout nerve = recovery.Wrist neutral or slightb; flexed.Database, I00 cases.

)pathy of thed difficult to:tion electro-iagnosis. Thebut becomes,sitional stresste by Richardad-the-scenes~l syndrome.aeuropathy is~v and surgicald ne~v treat-aificant nerve)roblems are.’arpa[ tunnel’.n neurolysis,~ one surgeonnents relatedpriate to freee level of theays leave the~e or on thehe importantrsonal obser-fact, handles,rve splay into the fascia

an Nerve at

~te Nerve

I carpal tunnel

y previousor wrist orand thoracic

g previoustt carpal

mrn of 40 mm

5 secondsaverage~ignificantixationurolysis 30

t of operativettion based onsensory splay

Recurrent Carpal Tunnel Syndrome, Epineural Fibrous Fixation, and Traction Neuropathy 499

of the superficialis muscle very adequately.Vascular recovery predictability returns within30 seconds after tourniquet release (Table 2).The exception to this clinical observation is the~,~asional case of recurrent carpal tunnel syn-

~rome where severe circumferential scarringhas clearly compromised a segment of thenerve. (This fact should give surgeons anotherreason to look beyond the ligament when doingsurgery at this level.)

Considering that the median nerve is leftpartially fixed at some point during routinecarpal tunnel surgery, the scar fix (see Fig. 1)may be out of sight of the surgeon, proximal tothe forearm or distal in the palm. Gliding~:ovements of the nerve, therefore, occur only:;~ a minimal way after surgery. New scar fixa-tion occurs on the nerve at the site of surgery,often placing the nerve into the edges or theundersurface of the wound. The patients lateroften complain of tenderness along their inci-sion in the palm and in the wrist. The Tinel’sfindings are common, deep pressure producespain, and supination and extension of the wristproduce traction phenomena on the mediannerve with symptoms. Generally, this symptom¯ ::mplex develops after the first 6 postoperative,., ceks in recurrent carpal tunnel syndrome, andmay become progressive in the months thatfollow. The fibrous fix or neurodesis matureswith the daily functions of the hand, wrist, andforearm. Many patients of strong stamina andgood muscle ability are able to produce effectiveadjustments in the length of the nerve beyonda fibrous fix point. This calls on the innate

of the nerve to lengthen and glide withinplanes in and around the perineural, epi-

and endoneural structures. This biologicchange has been well described by Lundborg.~

Haftekt showed that the epineurium had a highof elasticity and resistance to stretching,

but could also be the first nerve structure topast tensile strength. This represents

important part of the recovery process onthe median nerve following injury.

problem of recurrent carpal tunnel syn-is becoming more common. Ultimately,

.the demography of the failed CTS will becomeknown. When we retrace patient histo-

back to the beginning, we will find thatof these patients had a history of previousand unrecognized peripheral nerve prob-

in the upper extremity. This implies thatiagnosis of CTS was correct, but that

were other factors mitigating against thetreatment. The nerve was decom-

pressed but not able to glide after surgery, and

became fixed in the healing scar of the carpalligament and skin.

The incidence of thoracic outlet syndrome,or brachial plexus traction neuropathy, is in-creasing in nay statistics. This could reflect thefact that I have become more aware, and ourservice has become more attentive, to the meth-ods and procedure of diagnosing this importantproblem. This brings up the relationship of thecarpal tunnel syndrome and the thoracic outletsyndrome, and the question of the double-crushinjury. Is it really a factor, or are these merelycomplex neuropathies in the same extremity?a

Some of the eases that failed to show fullrecovery after carpal tunnel surgery in realityare complaining of a higher nerve problem inthe brachial plexus. They may have, on lateralabduction of their extremity, a C fiber burn inthe lateral trunk of the brachial plexus, probablyfrom the large sensory fibers in the C7 route tothe plexus, through the median nerve. Thismav closely approximate the complaints of se-vere carpal tunnel pain. Generally, however,this sensory pattern will be more intense in theindex finger, secondly the thumb, and pares-thesia may actually split the middle finger. Thispattern is fairly reliable, and has been men-tioned by Schwartzman in his article on braehialplexus traction injury in this issue.

Carpal Tunnel Release Alters Normal HandFunctions

Surgical opening of the transverse carpal lig-ament causes significant relaxation of the originof the muscles of opposition and pinch. Thehamate bone is the origin of the strong ligamentthat holds the radial ray in proper alignment.Opening the transverse carpal ligament permitsthe radial side of the hand or the thumb ray tofall away from the ulnar side" of the hand. Thesefactors produce weakness of thumb pinch thatsome patients complain about following carpaltunnel surgery.

Dividing the carpal ligament allows the flexortendons to drift more volar than usual, whengripping in neutral and partial flexion. Thischange in anatomy supports certain patient’scomplaints that they have difficulty with theirgrip strengths. This problem has been recog-nized, but until this time it has not beenpossible to offer a significant change to affectbetter recovery.

Following injury to the carpal tunnel, a groupof factors must be considered if improvementof the patient is to be realized. The median

500 JmnesM. Hunter

nerve generally presents in a radial locationalong the radial wall of the carpal tunnel. Itow-ever, when postsurgery scarring occurs, themedian nerve may present in a more volarposition, and may be traction-fixed in the ’.heal-ing scar of the ligament. This is one of theproblems seen during recurrent carpal tunnelsurgery. The nerve may also be fixed beyondthe carpal ligament, proximally in connectivetissue, or on the dorsal side of the anteriorsynovium of the flexor tendons by fibrous shea-thing. The median nerve may have a major fixby fibrous scar to the radial wall and to thetight sheaths of the flexor pollicis longus andflexor digitorum profundus of the index finger.The sensory nerves normally splay open in thepalm. They may become fixed together bvfibrous tissue and by the unyielding palmarfascia distally. In addition to these distal fixationpoints, there may be proximal fibrous fixationsbeyond the wrist to the forearm i:ascia.

A New Plan for Recurrent Carpal TunnelProblems

The median nerve in recurrent carpal tunnelsyndrome, following trauma or ~ailed surgery,may actually be fixed in adhesions, in the palmthrough the carpal tunnel, wrist, and into theforearm. The approach to this delicate problemis complete mobilization of the median nervethrough the hand and wrist. To accomplish this,epineural fibrous fixation is removed frmn the~,surrounding anatomy in the hand and wrist, sothat the median nerve can be lifted 40 to 50mm in the anteroposterior plane at the wrist(see Fig. 5E, Table i). This permits the nerveto move without tension on full ranges of motionof the hand, wrist, and forearm. This programhas proven successful in recovering salvageproblems, sufficiently that it has now beenapplied to the uncomplicated CTS. The uni-formity of improvement has been borne out in-the postoperative recovery, recorded by sensi-bility, nerve conduction studies, and clinicalassessment. This information, importantly, im-plies that the vascular nutrition of the rnediannerve became better as the biologic bed forgliding was uniformly established.

A plan to reverse the negative side of carpaltunnel surgery can be established. Return themedian nerve and the nine flexor tendons totheir natural, anatomic location deep in thecarpal canal, out of harm’s way. This wouldhonor the professional musician, the artist, andgive the working hand a new dimension of

recovery follmving carpal tunnel surgery. Theweakness of prehension and grip from divisionof the transverse carpal ligament could be elim-inated by reconstructing the central flexor ret-inaeulum of the hand. The results of 40 consec-utive cases, in which a combination of completemobilization.of the median nerves and recon-struction of the transverse carpal ligament havebeen reviewed. The early return of dexterityand strength has been impressive. Palm ten-derness is minimal to absent. Nerve recoveryseems ahead of schedule. The probability ofimproved long-term results is such that thisapproach could be used for the heavy workerand the performing artist.

MEDIAN NERVE MOBILIZATION ANDCARPAL LIGAMENT RESTORATION

Median nerve mobilization of the hand andwrist permits the median nerve and the flexortendons to return to normal anatomic positions,xvhich enhances comfort and function.

The purpose of mobilization is based on thefollowing:

Perineural fibrous fixation is present, signifi-cantly in patients with a history of previousinjury to the hand and wrist, and"patients withrecurrent Carpal tunnel syndrome, i.e., patientswith one or more previous surgeries for CTS.

If the tension fixing sites of epineural fibrousfixation (EFF) are not removed from the nerveso that the nerve can move freely with wristand finger movements, the nerve will becomefixed in the healing bed of the released trans-verse carpal ligament. Depending on the de-gree of fixation, nerve gliding programs--mayfail and the patient may remain disabled.

Mobilization of the median nerve done care-fully under magnification preserves the basicepineurium and the internal blood supply tothe nerve. The routine," 4-inch segments :mo-bilized in this procedure can be expected torecover visual circulation in 5 to 15 seconds(Table 9), except in unusual circumstances.

Contracted sections of perineural fibrosishave been removed up to 9. inches,-with vas-cular recovery slowed i to 9. minutes undervisual magnification. This doses the margin ofsafeW in median nerve mobilization at the car-pal tunnel level. In my opinion, if done care-fully, this is acceptable and good results can beexpected. This treatment permits the internalmobilization of the perineural and endoneurallayers to begin gliding in soft tissue patterns,as described by Lundborg.e I recommend that

surgery. Thefrom division

could be elim-tral flexor ret-s of 40 consec-m of completees and recon-ligament haven of dexterityce. Palm ten-erve recoveryprobability ofuch that thisheavy worker

TION ANDORATION

the hand andtnd the flexormie positions,tion.based on the

esent, signifi-, of previouspatients withi.e., patients

ies for CTS.leural fibrous~m the nervely with wristwill become

.leased trans-~ on the de-rograms maysabled.,e done care-’es the basic~d supply to.~gments mo-expected to15 seconds

astances.ural fibrosis~s, with vas-nutes underae margin ofn at the car-f done care-,~sults can bethe internalendoneural

ue patterns,mmend that

Recurrent Carpal Tunnel Syndrome, Epineural Fibrous Fixation, and Traction Neuropathy

the epineural fixation points that enter towardthe intrafasicutar bed be lysed only on theepineural surface. These nerve surfaces mayappear a little rough, but if complete mobilityis achieved, a functional gliding bed will occur.

Mobilization of the median nerve blends wellwith early postoperative gliding programs. Theroutine gliding of over 100 mobilized nerves atthe wrist level has been effective. Most patientsare satisfied, and their nerve conduction andsensibility testing grade up to better levels. Tenof these cases reflect no improvement in EMC,studies, but they were symptomatically morecomfortable. Three patients had reduced sen-.sibility but less pain or burning. These 10 case,,’,were all recurrent carpal tunnel syndromes in.dae Grade III salvage category (Table 2).

TECHNIQUE OF NERVE MOBILIZATIONAND RESTORATION OF TRANSVERSE

CARPAL LIGAMENT

possible, but they are generous, placed fromthe distal r~almar crease to the wrist. ~ crease andhen angled ulnarly beyond the antebraehial

fascia. Properly prepared, natients acce t this~ne~slon, in that the structural li aments will bereturned to their proper position and scar ten-derness ~s reheved (see F~g. 5A).

The median nerve trunk is visually identifiedin the proximal end of the incision and marked.The palmar sensory branch of the median nervecan be seen and mobilized. The palmar fasciais spread in the palm, and excessive thickeningsare excised. The most ulnar branch of themedian nerve is identified by tugging and tag-

ust distal to the transverse carpal ligamentFig. 5C).

The transverse arterial arch is protected anda large, blunt Kelly hemostat is placed in linewith the hamate bone. The instrument is angled30 degrees radially and passes deep to the radialsurface of the hamate. The instrument is then

The purpose of this procedure is to returnthe gliding bed of the median nerve and toprotect the nerve from outside tramna whilevorking. Of parallel importance is to return the

major pulley retinaculum of the flexor tendonsystem of the hand (see Fig. 3) and preservethe fascial origin of the thenar muscles of thethumb. The ultimate purpose, of course, is torestore the function and neurovascular nutritionof the nerve and the disabled hand to optimum.This means the best opportunity for hand re-habilitation.

All incisions are placed as cosmetically as

501

placed in a straight line to the carpal wristcrease, and the tip of the instrument is palpableon the ulnar side of the median nerve in theantebrachial t:ascia (see Fig. 5B). To incise thevolar and transverse carpal ligaments, the in-strument is-held securely against the hamate,and the scalpel follows the closed teeth of theinstrument carefully through the ligamentstructure. At the distal edge of the transversecarpal ligament, maximum light and specialattention are directed to the possibility of asensory nerve anomaly; this does exist andshould be constantlv checked. Also just distalto the ulnar edge o~ the transverse carpal liga-ment runs a consistent small sensorv nerveconnection from the ulnar nerve to the’mediannerve. The ligament is then opened longitudi-nally just radially to the hook of the hamate(see Fig. 5C).

The appearance and mobility of the nerve isnow studied in preparation for mobilization. Amarker dot is placed at the proximal edge ofthe hamate using a pick-up tooth forcep. Thefibrous epineurium is pinched, and the distalto proximal and proximal to distal excursion isnoted (see Table 1). The fascial fix from thelateral border of the nerve to the carpal tunnelis gently opened at the marker site around thenerve. The angular lift from the proximal edgeof the hamate bone is noted with wrist neutral,flexed, and extended (see Fig. 5E-G).

The nerve is gently mobilized in the carpalcanal under magnification. Dissections are car-ried distally to the motor branch. The motorbranch is stimulated, identified, and labeled.Multiple variations in the anatomy of the motorbranch are often noted. The motor nervem--aypass through the carpal ligament, around theedge of the carpal ligament, or leave the radialborder of the median nerve or any other quad-rant of the median nerve. The nerve may haveas many as three branches’ before it enters thenmscle. All these points must be observed andthe median nerve protected with a colored loop.Stimulation of the motor branch will measurethe function of the thenar muscle; it should bedone early in the procedure to overcome theeffect of the tourniquet. The response of themuscle is recorded on a scale of 0 to 4 +, andthis can be charted. The thenar muscle abduc-tion test, which has proved useful in the clinicalexamination of the traction median nerve, canbe confirmed at this time. The wrist, fingers,and thumb are extended and held for 30 to 60seconds. The wrist is brought to neutral andthe motor branch is stimulated electrically at 2MA. If the test had been positive prior to

502 James M. Hunter

surgery, it is likely to be positive at this time.A reduction of approximately 2 + may be seen;for example, if the nerve was 3+ on initialobservation, it may go to 1+. Generally, therecovery is very rapid on release of nervetraction.

The sensory splay of the palmer nerve anat-omy is checked by abducting the fingers andextending the thumb. All fibrous traction fixa-tions are excised under magnification. The sen-sory branches should spread to the distal edgeof the transverse carpal ligament. These nervesshould move freely in all planes, sufficient tobe lifted in the anteroposterior plane for in-spection (see Fig. 5D).

As the median nerve is mobilized at the wristcrease, fixation planes at the wrist, beneath theantebrachiat fascia, are lysed. Blunt finger ex-ploration of the median nerve is carried out inthe forearm, where the nerve passes underfascia and is fixed to the flexor digitorum super-ficialis muscle. Any additional fixed points arefreed. In instances of severe trauma to theextremity, the surgeons should look for a densefibrous fixed point or true neurodeses beyondthe incision. It may be necessary, to extend theincision more proximally to get forearm mediannerve trunk mobilization. The linear and ante-rior posterior movements of the nerve are nowmeasured at the proximal edge of the hamate(see Table 1):

Measurements of the nerve at the proximalhamate mark are taken with a neutral wrist,extension of the wrist with finger extension,and flexion of the wrist with fingers relaxed.Importantly, the mobilization goal in the ante-rior/posterior plane should be approximately 40ram; depending on the patient’s anatomy, this

’ could be 50 mm. The angular lift is done eitherwith a rubber loop or a rounded instrument.

.~ The anteroposterior angular measurementfrom a fixed point of the median nerve at thislevel closely approximates mobilization of thelateral trunk of the brachial plexus. In theclinical evaluation of mobilization of approxi-mately 40 brachial plexus at the supraclavicularlevel, the fiat curve of the first rib is used asthe bony fixed point to measure mobilization ofthe three nerve trunks from their transverseprocess fixed point to the fascial fix beyond thefirst rib. Mobilizations of the three trunks arebetween 45 mm and 55 mm for the uppertrunk, 32 mm and 38 mm for the middle trunk,and 28 mm and 35 mm for the lower trunk. Atboth ends of the peripheral nervous system inthe upper extremity, the mobility or elasticityof the nerve trunk and the biology to support

nutrition and internal circulation is similar. Thisobservation deserves further study.

The ~vound is irrigated and prepared fortransverse carpal ligament closure. Care istaken to prepare the radial and ulnar bordersof the ligament and to be especially observantto the contents of the Guyon canal ulnarly andto the motor branch of the median nerve at thedistal edge of the ligament radially. Closure ofthe transverse carpal ligament is carried outusing four 2-0 Dacron double-whip stitches(Fig. 7).

The marker loop is seen on the motor branchof the median nerve as the first stitches areplaced. With the stitches in the transversecarpal ligament, two or three chromic suturesmay be placed in the proximal fascia, however,this is optional based on nerve mobility. Beforeclosure of the carpal canal, the wrist is placedin a neutral position, all digits are relaxed, andthe tourniquet is released. The tourniquet timeis recorded, as is the visual vascular recoveryof the median nerve (Table 2, Fig. 8).

Before ligament closure, all moving struc-tures around the nerve are checked for gliding.Any tissue that has become fixed in the suturesis removed, and bleeding is controlled. In cer-tain posttraumatic cases, it may be necessary todrain the wound. When the wound is closed, a

~ ~

2-0 ethibond (4.)in ligament

2-0 chromic

Figure 7. A, B, C, Closure of the transverse carpalligament is carried out using four 2-0 Dacron double-whipstitches (2-0 chromic is optional).

504

median nerve traction, governed by hand,wrist, and forearm movements. Traction andtension suggest the intermittent disturbance ofnerve nutrition and nerve conduction as theelastic limits of the nerve are approached. Thesefactors accumulate and, in time, cause tractionneuropathies with pain. This is followed by areduced work capability. This impairment canbe reversed by surgical nerve mobilization fol-lowed by functional nerve gliding therapy. Abackground history injury to the hand and wristmay be significant, as well as factors such asoveruse and misuse of the hand and extremity.Prior to surgelT, the careful application of di-agnostic stress tests are essential, for the differ-ential diagnosis of fixation traction and posi-tional peripheral neuropathies.

Nerve mobilization supported by magnifica-tion and the techniques of hand surgery hasbeen successful by the methods discussed andhas permitted, importantly, the restoration ofthe anatomic retinaculum for the flexor tendonsystem. This can be restored in carpal tunnels~argery and reconstructed with basic ligamentmaterial in recurrent carpal tunnel surgery.

ACKNOWLEDGMENT

The author wishes to acknowledge Drs. SavvosPoulos, Michael Behrman, and Robert Piston for

James M. Hunter

their editorial assistance; and Lynn Hawkins, MarieHurtado, and Lucy Zedolik for manuscript prepara-tion.

REFERENCES

1. Haftek J: Stretching injury of peripheral nerve: Acuteeffects of stretching of rabbit nerve. J Bone Joint Surg[Br] 52:354, 1970

2. Lundborg G: Nerve Injury and ]Repair. New York,Churchill Livingstone, 1988

3. Millese H, et al: The gliding apparatus of peripheralnerve and its clinical significance. Ann Hand Surg9:87-97, 1990

4. Narakas AO: The role of Thoracic Outlet syndrome inthe Double Crush syndrome. Ann Hand Surg 9:331-340, 1990

5. Phalen GS: The carpal tunnel syndrome: Seventeenvears experience in diagnosis and treatment of sixhundred and fifty four hands. J Bone Joint Surg [Am]48:211, 1966

6.~ Spinner M: Injury to the Major Branches of PeripheralNerves of the Forearm, ed 2, 1978

7. Tubiana R: Carpal tunnel syndrome. Some vie~vs on itsmanagement. Ann Hand Surg 9:325-330, 1990

8. Wilgis EFS: Murphy JR: The significance of longitudinalexcursion in peripheral nerves. Hand Clin North Am2:761-766, 1986

Address reprint requests to

James M. Hunter, MDHand ]Rehabilitation Center

901 Walnut StreetPhiladelphia, PA 19107