Median and Ulnar Nerve Injuries: V

A Long Range Study with Evaluation of the Ninhydrin Test,Sensory and Motor Returns

J. EDWARD FLYNN, NI.D., WILLIAMi F. FLYNN, M/I.D.

From the Department of Surgery, Tutfts University School of Medicine and theFirst (Tufts) Surgical Service, and the Fifth (Harvard1)

Sturgical Service, Boston City Hospital

A STUDY was made of results of repairof transected median and ulnar nerves oneto 12 years after operation in 80 cases. Inall cases the nerves were transected at thewrist level and primary repair was per-formed. Evaluation by the ninhydrin testwas made and sensory and motor restora-tion w,ere investigated.

Sensory function in the band cannot bedetermined accurately by the cotton wooltest for touch, pin-prick for pain, and ordi-nary methods of testing sensations ofwarmth and cold. Some subjective tests,howvever, have proved valuable. Of thesethe Wlleber test5 is best, in which a two-point discrimination below 12 mm. is nor-mal. The Seddon coin test4 and 'Mobergpick-up test2 are also valuable. In thesea patient with median nerve loss grasps acoin or other object with the thumb, ringand little fingers rather than with thethtumb and index finger.An objective test for sensory function is

most desirable. The ninhydrin test, prac-ticed by Moberg,' is objective. The basisfor this test is: a hand lacking tactileperception also lacks sudomotor function.Secretion of sweat is regulated by the sym-pathetic nervous system. Fibers of thesympathetic nervous system enter the bra-chial plexus in the cervical region as postganglionic fibers, and then follow the sen-

e Submitted for ptublication January 17, 1961.Presented at the Second Annual Congress on

Trauma, National University of Mexico, 'MexicoCity, October 11, 1961.

sory pathways. W\hen a peripheral nerve issevered, sweat glands in the skin of theregion supplied by this nerve lose innerva-tion and sweating ceases within a fewminutes.

Basis for Ninhydrin Test

Ninhydrin stains amino acids and lowerpeptides with great sensitivity.3 The fol-lowing amino acids are found in sweat:alanine, asparaginic acid, glutamic acid,methionine, serine and thionine.1 The nin-hydrin test is essentially finger printing.

Technic of Ninhydrin Test

A 1.0 per cent solution of ninhydrin inacetone is prepared by dissolving 10 Gm.of ninhydrin in 1,000 cc. of acetone. Thissolution keeps for several months. Ten ml.of the solution are mixed with 5gtt. ofglacial acetic acid. The acidulated soltutionlasts about a week. It is usually better toprepare fresh acidulated solution daily.

Prints are obtained by pressing the pulpsof each finger against a 15 x 3.0 cm. stripof glazed white paper. Porous paper shouldnot be used. The print is developed bydipping the paper in the acidtulated solu-tion. The paper strips dry quickly, and arethen warmed in air at 1000 to 120° C. forfive minutes. Pturple dots of surat aminoacids then become visible but it is wvellto wait three days before fixing the printsbecause the dots become more distinct.Prints are fixed by dipping the paper in a

1002

\VunCle1 \IED)IAN ANI) lULNNUmber 6

1.0 per cenit soltution of copper nitrate ina 5:95 mixture of water and methyl alcoholor acetone, acidified by a few drops ofconcentrated nitric acid per 100 ml.

Relation Between Sensation andSudomotor Function

WN'hen a peripheral nerve is severed, thearea of skin that it supplies ceases to sweat.On examination the regions with intactsensory function sweat normally and givenormal prints, but the denervated regionsleave no print. In a hand with the mediannerve transected at the wrist there is lossof sensation and sweating over the volaraspect of the thumb, index, and middlefingers, and radial half of the volar aspectof the ring finger. In a hand with the ulnarnerve transected at the wrist there is lossof sensation and sweating over the volaraspect of the little finger and the ulnar one-half of the volar surface of the ring finger(Fig. 1).

Cutaneous Sensibility in the Hand

Wle agree with Moberg2 that there arethree grades of cutaneous sensibility in ahand: precision sensory grip, gross grip,and protective sensibility. A hand whichlacks tactile perception is blind. It cannotbe used without the aid of the eyes, andone does not know whether or how thehand holds an object, or what the object is.

TABLE 1. Low Ml1edian and (Inar Nerve Injuries

Years

BetweenRepairand

Evaluation

23

678

9101112

Low

Meedian40 Cases

1

26104

372

Ulnar40 Cases

7

74

32943

sAll NERV7E INJURIES 1003

Fic.. 1. Relation between sensation and all(Idootorftunction. Ninhydrin test.

Grade I. Precision Sensory Grip: Thisis required for buttoning a shirt, turninga bolt, tying a bundle, sewing, and windinga watch. Loss of this sensation can bedetermined objectively by the ninhydrintest. Subjective tests of value are the W;\ebertwo-point discrimination test, Seddon's cointest, and Moberg's picking-up test.Grade II. Gross Grip: This may be eval-

uated objectively by examining for thepresence of callouses, or by testing abilityin lifting a shovel, hammer, bottle orbasket.Grade III. Protective Sensibility: This

may be jtudged from the history. Lesionssuch as burns and infected wounds mayprovide further evidence. It is interestingto note how rarely precision sensory gripis restored after transection and repair ofmedian and ulnar nerves in the wrist.

Comparison Between Tactile Sensibilityand Sudomotor Function

Forty cases of median nerve and 40 casesof tulnar nerves transected and repairedprimarily at the wrist level were ex-amined from one to 12 years after operation(Table 1).

FLYNN ANI) FLYNN

AME T IMF jPROTECTIVESICE SENSIBILIlN.

_ TwS. 1xsY...

*~ ..s :: I.:..:.

Annals of SurgeryD)ecember 1962................. ....... ::. ::. ..... :. :.

I..........;,, .s W _

.....*...i11 .... ............. .. , 1.:2 ........... . ,. ......... ...:. i.' 'i _. ' ... _

FIG. 2, 3. Mledian nerve loss.

The results of the ninhydrin test werecompared with the results of the two-pointdiscrimination test, the Seddon coin test,and the MIoberg picking-up test. Normalsudomotor function is indicated by 3, mod-erately reduced by 2, greatly reduced by 1,and absent by 0. Normal precision sensorygrip, gross grip and protective sensibilityare indicated by +i++, moderately re-duced by + +, greatly reduced by +, andabsent by 0.

In eight cases of median nerve repair it

is interesting that return of sudomotor func-tion as evidenced by the ninhydrin test iscomparable to return of two-point discrimi-nation. WN"ith return of two-point discrimi-nation of 12 mm. a ninhydrin test of 2 isnoted. W;'ith two-point discrimination ofgreater than 26, a ninhydrin test of 1 isnoted (Fig. 2).More detailed study of sensory return

wvith median nerve repair shows that sudo-motor function is comparable to two-pointdiscrimination test and to other subjective

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1006 FLYNN AND FLYNN Annals of Surgery

TABLE 3. Percentage Sensory Recovery, 40) Median, 40 Ulnar Nerve Repairs

Two-Point Precision Gross Protective SudomotorDiscrimination Grip Grip Sensibility Function

SO failure 0 0 0 0 0Median 3 3 3 3 3Ulnar 0 0 0 0 0

S1 poor 0 0 0 + 2Median 27 27 27 27 27Ulnar 30 30 30 30 30

S2 fair >20 0 + ++ 1Median 50 50 50 50 50Ulnar 50 50 50 50 50

S3 good 12-20 mm. + or- ++ ++ 2Median 17 17 17 17 17Ulnar 20 20 20 20 20

S4 Excellent <12 mm. +++ +++ +++ 3Median 3 3 3 3 3Ulnar 0 0 0 0 0

Normal grip function +++; Normal sudomotor function 3.

S4 excellent

S3 good

S2 fairS1 poorSO failure

Totals

M5 excellentM4 goodM3 fairM2 poor

N1-MIO failure

Totals

TABLE 4. Sensorv Recovery of .lMedian and Ulnar Nerve Repairs

Median

ZacharyOur 5 Yrs. Our

C C/ C

3 9 0

17 29 20

50 15 5027 47 303 0 0

40 278 40

TABLE 5. Median nerve, Motor Recovery

Classification

Flexion ofInterphalangeal Adduction

Joints of Thumb

900 each 600-800500-900 450-600300-500 200-450100-300 00-200

0n-10o 0

R,

Ourc-c

7153825

15

40

Ulnar

Zachary5 Yrs.

C'

0S3+ 3

S3 2815540

390

'esults

Zacharx5 Yrs.

C,c

61341

28 MI +

12 Il1290

MIEDIAN AND ULNAR NERVE INJURIES

tests. With sudomotor function of 2 andtwo-point discrimination of 12 mm. or less,there is usually some return of precisiongrip (and a positive picking-up test). Witha ninhydrin test of 1, and a two-point dis-crimination of 26 mm. or more usuallythere is loss of precision sensory grip, nega-tive picking-up test and often a negativegross grip (Table 2).

In three cases of ulnar nerve repair, itis also noted that return of sudomotor func-tion is comparable to the return of two-point discrimination. With two-point dis-crimination of from 9.0 mm. to 12 mm. aninhydrin test of 2 is noted (Fig. 3).The more detailed study of ulnar nerve

repair shows that precision sensory grip,and the picking-up test are frequently neg-ative, even when the two-point discrimina-tion is 12 mm. or less and the ninhydrintest is 2 (Table 2).An analysis of the results of median and

ulnar nerves sutured at the wrist was made.Sensory and motor recovery were studiedand were compared with the results re-ported by others. Sensory and motor recov-ery were assessed separately and recognizedgrades of restoration from total paralysisto complete recovery were recorded.

Sensory recovery is graded from SO fail-ure, to S4 excellent. The criteria for differ-ent grades are noted in Table 3.These criteria were compared to criteria

suggested by Highet in a memorandum ad-dressed to the British Nerve Injuries Com-mittee."3 Highet's criteria for sensory re-covery are:

Stage 0-absence of sensibility in the auitono-mous zone of the nerve.

Stage 1-recovery of deep cutaneous pain sen-sibility within the autonomous zone.

Stage 2-return of some degree of superficialpain and tactile sensibility within the autonomouiszone.

Stage 3-return of superficial pain and tactilesensibility throughout the autonomous zone withthe disappearance of over-response.

Stage 4-return of sensibility as in Stage 3 witlhthe addition that there is recovery of two-pointdiscrimination within the auitonomous zone.

Study of return of sensory functions withmedian and ulnar nerve suture reveals thatthe greatest percentage of results is in S1,poor, to S2 fair (Table 3). These comparewith results reported by Zachary" (Table4).

Motor recovery with median nerve su-ture are graded from MO, failure, to M5,excellent. These criteria are based upon

TABLE 6. LInar Nerve, Alotlor Recovery

Classification

Clawing

Hyper-tensionM. P.Joints

FlexionDeformity

I. P.Joints

DigitalAbductionand Adduc-

tion

ThumbIndexPinch

FlexionDistal JointRing andLittle

Motor Recoverv

ZacharyOur 5 Yrs.('(''C I(C

0 050 10°-200

5-10 200-400

100-200 400 800

100-200 400-800

Normal

2 NormalPoor

Normal

2 Normal

4 Normal

0 Weak

500 900

300 400

200-300

100-200

MIl 00-10(0) WNeak -

MIO 0°

0 0

8 5

15 14

MI2 + 2757

M2 49

20 5

40 384

Volume 156Number 6 1007

M5 excellentM4 goo(d

M3 Fair

M2 poor

MM1-OI( failture

'rotals

FLYNN AND FLYNN Annals of SurgeryDecember 1962

FIG. 4. Ulnar nerve loss.

the extent of recovery of active flexion inthe digits and abduction of the thumb(Table 5). Highet's criteria for motor re-

covery are:

Stage 0-no contraction.Stage 1-return of perceptible contraction in

proximal muscles.Stage 2-return of perceptible contraction in

both proximal and distal muscles.Stage 3-return of function in both proximal

and distal muscles to suich an extent that all im-portant muscles are of sufficient power to actagainst resistance.

Stage 4-return of function as in Stage 3 withthe addition that all synergic and isolated move-

ments are possible.Stage 5-complete recovery.

Our study of return of motor functionwith median nerve suture shows that more

than half the cases are graded from M2,poor to M3, fair. These results comparewvith those of Zachary (Table 5).Motor recovery with ulnar nerve suture

is graded from MO, failure to M5, excellent.Criteria are based upon the angles of de-formity in the three joints with clawing,strength of thumb-index pinch, and activeflexion of distal phalanges of the ring and

little fingers (Table 6). Our findings withreturn of motor function with ulnar nerve

suture show that the greatest percentage

is in Ml, poor, to M2, fair and comparablewith those of Zachary (Table 6).

ConclusionsThe ninhydrin test is a valuable adjunct

in determining sensory return after sutureof median and ulnar nerves at the wrist.This test is comparable to the Weber two-point discrimination test and other subjec-tive tests. The two-point discrimination testis better to show normal differences in thepulp of the index and little fingers, betweenpulp of finger and volar aspect of base ofproximal phalanx, and between volar as-

pect of proximal phalanx and palm. Themain value of the ninhydrin test is that itis objective and records are permanent.This printing test is valuable in demonstrat-ing small degrees of sensory function in a

damaged nerve and in showing regionswith and without sensation.

Repair of divided median and ulnarnerves at the wrist give a fair chance ofuseful recovery. Perfect recovery is rareand possibly never occurs, but was closelyapproached in one repair in a child. Fortyper cent of meldian nerve repairs weremotor failures or poor. Tendon transplaintswere not performed in all of this group.Absence of abduction and opposition may

1008

Volume 156 MEDIAN AND ULNAR NERVE INJURIES 1009Number 6

be so well compensated for by the flexorpollicis longus, extensor pollicis longus andthe adductor pollicis that there is goodgrasp. Our indication for tendon transfer inmedian nerve palsy is when the thumbcannot be abducted sufficiently to grasp anobject such as a drinking glass.

Seventy per cent of ulnar nerve repairswere either motor failures or poor. Tendontransfer, to stabilize the second metacarpo-phalangeal joint and provide for firm pinchbetween the thumb and index finger, wasperformed in most cases after transec-tion of the ulnar nerve at the wrist.Proper splinting of the metacarpo-phalan-geal joints in 300 of flexion, with a plastercuff allows the extensor digitorium com-munis to extend the middle and distal pha-langes and control clawing. Tendon transferto correct clawing is performed when thisdisability is so pronounced that an appleor orange cannot be grasped. Tendon trans-fers for clawing were performed in about30 per cent of cases of ulnar nerves tran-sected at the wrist.

Summary

The ninhydrin test is useful in determin-ing sensation in the hand because sensationvaries directly with sudomotor function.

Long range examination of 40 medianand 40 ulnar nerves transected at the wristand repaired primarily reveals good sen-sory return in about 20 per cent with eachnerve. Good motor recovery was noted inabout 22 per cent of median nerves and8.0 per cent of ulnar nerves. However, littlepractical disability occurred as most pa-tients returned to their regular occupations.

Bibliography1. Hier, S. W., T. Cornbleet and 0. Bergeim:

The Amino Acids of Human Sweat. J. Biol.Chem., 166:327, 1946.

2. Moberg, E.: Objective Methods for Determin-ing the Functional Value of Sensibility in theHand. J. Bone & Joint Surg., 40-B:454, 1948.

3. Oden, S. and B. Hofsten: Detection of Finger-prints by Ninhydrin Reaction. Nature, 174:449, 1954.

4. Seddon, H. J.: Methods of Investigating NerveInjuries. In Peripheral Nerve Injuries, p. 1.,Ed. H. J. Seddon, MIedical Research CouncilSpecial Report Series No. 282, London: HerMIajesty's Stationery Office, 1954.

5. Weber, E. II.: Cutaneous Sensation in TextBook of Physiology. Ed. E. A. Schafer, NewYork, The MacMillan Co., p. 928, 1900.

6. Zachary, R. B.: Results of Nerve Suture. In Pe-ripheral Nerve Injuries, Ed. H. J. Seddon,Medical Research Council Special Report Se-ries, No. 282, London: Her TMajesty's Sta-tionery Office, 354, 1954.