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Translated Article

‘ ‘TINGLING’ ’ SIGNS WITH PERIPHERAL NERVEINJURIES

J. TINEL

Original citation: La Presse Medicale 47 (1915), 388–389

We know how difficult it is to be precise when makingdiagnoses for peripheral nerve injuries. Is the nervesevered, compressed, torn or obstructed, or is it in theprocess of regenerating itself ? Is the palpable neuromapermeable or not for the axon cylinders ? Has suturing anerve been successful or not ?y So many vitallyimportant queries confront clinicians daily as far asthe prognosis and treatment are concerned.

We think that routine studying of tingling produced bypressure on the nerve may be extremely beneficial forsolving these problems.

Pressure on an injured nerve trunk quite oftenproduces a tingling sensation, felt by the patient at theperiphery of the nerve and localized to a very precisearea of the skin.

It is extremely important to differentiate this tinglingsensation from pain that is sometimes also caused bypressure on a traumatized nerve. Painfulness is a sign ofneuritic pain; tingling is a sign of regeneration; or, morespecifically, tingling indicates the presence of youngaxons in the process of growing.

Painfulness from neuritic pain is almost always localpain, experienced in the same place where the nerve isunder pressure.

When it affects the whole of the path of the nerve, itnevertheless exists and is more pronounced in the areawhere pressure is applied. It is almost always accom-panied by pain from pressure on the muscle masses, andmore often than not the muscles are more painful thanthe nerve.

Tingling from regeneration is not painful; it is a slightlyuncomfortable sensation that patients usually compareto electricity. It is hardly noticed in the area that ispressed and is much more noticeable in the correspondingcutaneous area. The muscles that are next to the‘‘tingling’’ nerve are not painful.

In almost every case it is easy to tell the differencebetween these two types of phenomena, pain andtingling, that are caused by pressure on the nerve. Theyrarely co-exist on the same nerve, or more to the point,they rarely co-exist in the same area of the affectednerve; but we can see that they can exist on the samenerve trunk.

These two different signs caused by pressure on thenerve are additional to the sensory symptoms revealedby exploring the skin. In fact, neuritic pain is oftenaccompanied by painful hyperaesthesia of the skin;regeneration of the nerve manifests itself by paresthe-siae, the most common of which is the rather painful

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tingling feeling associated with hyperaesthesia caused bytouching, pricking and especially by lightly stroking theskin.But in every case the symptoms produced by pressure

on the nerve, the pain that indicates irritation of theaxons or the tingling which indicates regeneration aremuch easier to distinguish from each other than signs ofskin sensitivity. They are also much more constant andoccur much earlier; they provide much more precise,permanent and more useful information.The systematic study of tingling caused by pressure on

the nerve very often enables us to:Find out if the interruption to the nerve is complete or

partial.Determine the exact location and the extent of the

injury.Detect regeneration of the axons at an early stage, to

follow its progress and to assess the extent of it.A few examples are given below:1. Where the nerve is completely severed, there is a very

clear area on the path of the nerve trunk where pressureresults in tingling in the cutaneous area of the nerve.This tingling area is quite small; it is no more than 2 to

3 cm; it is permanent and absolutely constant; it does notalter for weeks and even months. It is only on the path ofthe nerve and no other place can be found above orbelow the injury where pressure can cause tingling.This area indicates that at this precise point, the axons

were suddenly disrupted and have undergone regenera-tion but, powerless to fight the obstacle or find theperipheral segment again, they have amassed to form alarger neuroma.2. With complete interruptions to the nerve by very firm

compression, the same characteristics of constancy,permanence and precise limitation are found; but thetingling area is wider; it can reach up to 6, 8 or 10 cmalong the path of the nerve. For example, with thefrequent compression of the radial nerve caused by afractured humerus, we can follow the entire path of thenerve enclosed in the bone callus by studying theresultant tingling; we can find out if the nerve is affectedthroughout the whole callus and even if the nerve isdamaged in the upper or lower part of the fracture.It should be noted that, with a bone callus, by simply

pressing on the nerve it is difficult to produce tingling; itis more easily produced by gently tapping the callus. Inany case, if the tingling area remains constant and doesnot extend beyond the lower limit of the callusconstriction and if the nerve does not cause tingling

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below the injury for several weeks, this is because thecompression has constricted the nerve quite severely andthe axons have been damaged and cannot grow throughthe construction.

3. In certain cases there can be two different tinglingareas on the same nerve, caused by two separate injuries.

For example, we saw two wounds in a case of radialparalysis caused by injury to the upper part of the arm.There was an initial tingling area on the radial nerve atthe level of the exit hole of the bullet, on the posteriorsurface of the arm, and a second, larger area on theexternal surface of the limb at the level of a very largefracture callus. These two areas were constant andlimited and no signs of tingling were found below thebone callus. The operation showed that the nerve hadfirstly been partly destroyed by the passage of the bulletand that some fibres that had escaped this destructionwere compressed and divided lower down in the fracturecallus.

Partial tingling of a nerve can also be observed.Pressure on the sciatic nerve, for example, can reveal alimited injury to its external or internal part, with thetingling feeling localized to the cutaneous area of eitherthe external popliteal nerve or the internal poplitealnerve.

Another example is a man with paralysis of the sciaticnerve caused by an injury to the middle part of the thigh,who was experiencing a double tingling sensation;pressure on the nerve in the position of the woundproduced tingling on the sole of the foot, i.e. in theinternal popliteal nerve area; but on the other hand,pressure on the nerve below the injury caused a muchwider area of tingling on the back of the foot, in theexternal popliteal area and this pressure area progres-sively reached the popliteal fossa. In this case, on theone hand, the internal part of the sciatic nerve wascompletely damaged and produced a permanent tinglingsensation; on the other hand, there was partial damageto the external part of the nerve, with progression of theregenerating axons and pressure area causing tingling tothe popliteal fossa.

4. Partial damage of the nerve or, more specifically,injuries that allow the passage of regenerating axons, ischaracterized by the progressive expansion of thetingling area experienced.

Consequently, we see that tingling is experienced belowthe injury and progressively extends towards theperiphery along the path of the nerve. A nerve thattingles below the injury is a nerve that is partially orcompletely regenerating itself. So, the slow progress ofthe axons can be followed week by week; the speed ofthe nerve’s recovery can be seen; moreover, the extent ofit can be assessed, depending on the intensity of thetingling caused and the extent of the cutaneous areaaffected.

The same applies to nerve sutures where, by assessingthe progressive size of the tingling area, the success ofthe operation can more or less be ascertained.

As the tingling area extends and becomes morepronounced towards the periphery, it decreases andeven ends up completely disappearing around thetraumatized area. Moreover, it moves erratically, whilststill affecting a considerably wide area.It is therefore still necessary to explore the nerve along

the whole of its path. For example, we examined a manwith complete paralysis of the sciatic nerve; he had thewound on the upper part of this thigh for 5 months; theparalysis was still complete even though there was stillsome muscular tone and the numb area seemed to beslightly smaller. We looked without success on thesciatic nerve for a tingling area, on and above the injury,and we wondered if its absence might indicate anincorrect diagnosis. But, on the contrary, the tinglingwas much lower down, on the nerve branches, in thearea of the popliteal fossa reaching as far as the middlepart of the leg. Consequently, it was a nerve that wasalready in an advanced state of repair; in fact, we weresoon able to see faradic contractility reappear in somemuscle bundles of the gastrocnemius, peroneal nervesand tibialis anterior muscle.5. The same gradual extension of the tingling area can

be found in partial damage with neuritic pain.Sometimes, though this is rare, it seems that the

occurrence of pain and re-growth can affect the samenerve; but this is quite difficult to interpret. Nonetheless,generally with neuritis the patient experiences pain froma painful swelling or even very painful tingling, ratherthan the sensation of real tingling.However, in most cases tingling gradually replaces

neuritic pain caused by pressure on the nerve; in a way itfollows on from it. As the tingling area decreases, thenerve trunk and the adjoining muscles stop beingpainful; for example, a sciatic nerve that is no longerpainful tingles when the thigh is pressed, whilst thenerves and the muscle mass in the leg are still painful.It is easy to see from these few examples the

advantages of having a tingling feeling. It goes withoutsaying that the systematic study of this symptom maynot under any circumstances dispense with the meticu-lous examination of motor, electric, sensory and trophicproblems. It should be used alongside this and, in mostcases, just confirms and clarifies the clinical data alreadyobtained from this examination.It would be much more harmful to place too much

importance on signs of tingling that can sometimes bemissed and the following are some examples:1. Tingling caused by pressure on the nerve hardly

ever occurs earlier than the fourth or even the sixth weekfollowing the injury.In fact, we know that any nerve injury, whether a

division or compression, is followed by an initial periodof degeneration: descending degeneration, or Walleriandegeneration, as far as the nerve endings; ascendingdegeneration or retrograde degeneration generally onlyaffects a few areas of the nerve but occasionally itaccompanies quite severe damage to the nerve cells. It is

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TINGLING SIGNS 89

only after this initial degenerative phase that fibrillationof the axons in the central section, and their develop-ment and growth, occurs. It seems that in humans thisregeneration phase only appears after about 3 or 4weeks; however, it can appear earlier or later, dependingon the individual’s age, state of health and regenerativecapabilities.

It is during this neoformation period of the axons ofthe nerves that tingling sensations seem to occur.

2. Similarly, the tingling disappears once the nerve hasreturned to its normal condition, and once the newlyformed axons have reached maturity. The tingling seemsto stop after about 8 or 10 months. Naturally there arewide variations, depending on the individual, theinjuries and the length of the nerve that needs toregenerate. We have observed that tingling disappears inan erratic way, by gradually moving towards theperiphery of the nerve.

3. Finally, in some rare cases tingling may not occur,apart from within the limits at the start and end that we

have just outlined. This occurs when the injury is veryslight and has not significantly destroyed the nerve fibresor, conversely, because there is no regeneration assometimes happens with elderly, ill or infectious patientswith severe nutritional problems.Tingling, therefore, is not always an absolutely

constant or permanent sign that is easy to interpret.Under no circumstances can the meticulous andrepeated examination of the patient be replaced.Tingling can only be of use when combined with allthe other clinical symptoms.Nonetheless, with all these reservations, it seems to us

that tingling is sometimes likely to bring to light certainproblems concerning neurological diagnoses and toprovide useful information for the prognosis andtreatment of peripheral nerve injuries.

r 2004 La Presse Medicale. Published by Elsevier Ltd. The British Society for Surgery of theHand.doi:10.1016/j.jhsb.2004.10.007 available online at http://www.sciencedirect.com