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TRIGEMINAL NERVE INJURY: DIAGNOSIS AND MANAGEMENT 1042-3699/92 $0.00 + .20

MANAGEMENT OF PERIPHERALNERVE INJURIES

Basic Principles of Microneurosurgical Repair

A. Lee Dellon, MD

The management of peripheral nerve in-juries has become increasingly sophisticatedas our understanding of the pathophysiologyof neural degeneration and the basis ofneural regeneration has improved. The pur-pose of this article is to focus on the surgicalprinciples related to nerve injury and repair,forming a bridge between the early articleson physiology and pathophysiology, sensoryevaluation, and electrical and radiologic di-agnosis and the articles to follow which dealwith specific problems of individual branchesof the trigeminal nerve. ~’

The management of peripheral nerve in-iuries has been made enormously easier bythe classification of these injuries by Seddonand Sunderland. The details of these classi-fications have been reviewed recently andupdatedTM and are covered again in the sec-ond article of this issue. Sir Sidney Sunder-land has catalogued in encyclopedic fashionmost of the knowledge related to nerves,a°but this work is certainly not "user friendly."A multiauthored text attempting to coordi-nate the experience of hand surgeons (gen-eral, orthopedic, and plastic surgeons) ap-peared in 1980.25 Since then, experimentalmodels for chronic nerve compression, neu-roma formation, and neural regeneration, aswell as advances in sensibility evaluation,

have permitted a coordinated approach tothe management of peripheral nerve injuriesthat has proven effective for both the upperand lower extremities. This systematic ap-proach appeared as a monograph by Mac-kinnon and Dellon in 1988.17 It is appropriateat this time to extend these concepts to themaxillofacial region, and the trigeminal nervein particular.

PERIPHERAL VERSUS CENTRALNERVE

Is the trigeminal nerve a peripheral nerve?And does it matter? Nerves within the CNSare believed, in general, not to regenerate orto regenerate poorly, whereas those of theperipheral nervous system are known to re-generate (although perhaps not as well as wewould wish). If the trigeminal nerve, beinga cranial nerve and therefore being closelyrelated to the brain, is not a peripheral nerve,perhaps we need not consider how to recon-struct it! If, however, the trigeminal nervebehaves like a peripheral nerve, then wehave the potential to restore its function.

Nerves in the upper and lower extremitiesare considered peripheral nerves, and so arethose of the thorax. The nerves within the

From the Division of Plastic Surgery and the Department of Neurological Surgery, Johns Hopkins University,Baltimore, Maryland

ORAL AND MAXILLOFACIAL SURGERY CLINICS OF NORTH AMERICA

VOLUME 4o NUMBER 2 ¯ MAY 1992 393

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brain and the spinal cord are classically con-sidered part of the CNS. What are cranialnerves? They connect neurologic areas thatare intracranial and extracranial, but they arenot all the same. In particular, the optic nerveand the olfactory nerve originate from cellbodies that are considered embryologic ex-tensions of the brain. These nerves are sur-rounded not by supporting connective tissuesheaths that contain Schwann cells, but byglial cells such as oligodendrocytes. Al-though the oligodendrocyte does producemyelin, it is immunologically distinct fromthat produced by Schwann cells. The glialsupporting cells of the CNS do not appear toproduce the neurotrophic factors necessaryto support neural regeneration.I’ 3, 13, 32 Thus,the first and second cranial nerves are inreality part of the CNS, and blindness andanosmia, respectively, result from injury tothese two nerves. In contrast, the other cra-nial nerves originate from cells within thebrain and extend as axons into tissues exter-nal to the CNS. These other cranial nervesare surrounded by connective tissue sup-porting structures that contain Schwanncells, which are highly supportive of neuralregeneration. These observations have beenconfirmed by the ingenious models fromAguayo’s laboratory, where segments of aperipheral nerve, e.g., the rat sciatic, areinserted into the CNS, e.g., the spinal cord,with the result that axons from the spinalnerve regenerate into and along the sciaticnerve.2, 28 Thus, the injured trigeminal nerve

has the capacity for neural regeneration.

NERVE REGENERATION AS ASOURCE OF PAIN

With chronic compression, the response ofthe nerve is increased fibrosis of its connec-tive tissue support structures, such as theepineurium and the perineurium, and de-myelination of individual nerve fibers. 18 Ex-amples of this type of nerve problem in themaxillofacial region are uncommon, in gen-eral, with the exception of facial nerve com-pression within the temporal bone, i.e., Bell’spalsy, and are rare for the trigeminal nervein particular. Conceivably, following facialtrauma there may be blunt or crush typedamage to the infraorbital nerve or the men-tal nerve, or following a radical neck dissec-tion scarring or electrocautery injury to the

lingual nerve that might constitute this de-gree of nerve injury. The appropriate treat-ment surgically would be an external neurol-ysis of the involved nerve, which involvessurgically-separating the nerve from its ad-herent surrounding tissues. Once separatedfrom surrounding scar, the possibility thatsignificant intraneural scarring may be pres-ent must be considered. With microsurgicaltechnique, the epineurium should be openedacross the region of compression. If theneural tissue within is soft and is character-ized by bands of Fontana,23 no further intra-neural dissection is indicated. Becausebranches of the trigeminal nerve have asmany as 20 fascicles, intraneural neurolysiscould be done at this point.12, 20 Because therewould not have been axonal loss with thisdegree of injury, a period of sensory recoverywithout discomfort would be expected. Therecovery might occur almost immediately fol-lowing the decompression of the nerve orover a period of 3 to 6 months.

With more prolonged compression, orcompression of a more severe degree, e.g.,higher pressure, axonal loss occurs. In themaxillofacial region this is most often seenassociated with facial fractures in which theinfraorbital nerve is directly in the fracturesite of the zygoma or the inferior alveolarnerve is directly in the fracture site of themandible. Neural regeneration is the normalresponse to a nerve injury severe enough tocause axonal loss. When neural regenerationis blocked or impeded, however, as it wouldbe by the compressive forces of bone at afracture site, normal regeneration does notoccur. Abortive neural regeneration resultsin the formation of a neuroma, which mayor may not be painful.

Complete or incomplete division of thenerve, of course, also results in distal degen-eration of the nerve, as described by Wallerin 1850.33 If the two ends of the divided nervelie in close proximity, as they might withinthe alveolar canal, where the division mighthave occurred during a sagittal split osteot-omy, the normal process of neural regener-ation may result in the correct direction ofproximal axonal sprouts into the distal por-tion of the nerve. Almost. always, however,a percentage of the sprouts fail to be directedappropriately and develop into a "sutureline" or neuroma-in-continuity. As just sug-gested, this may well be the result even if a

MANAGEMENT OF PERIPHERAL NERVE INJURIES 395

microsurgical repair of the divided nerve isdone. This neuroma, again, may or may notbe painful. Furthermore, the process ofneural regeneration implies the distal pro-gression of axonal sprouts over time. Thisoften is perceived by the patient as a painfulexperience, even though its duration is finite,on the order of 3 to 6 months. If neuralfunction appears to be recovering, but signif-icant pain persists at the site of injury, neu-rolysis of the nerve at this site may be indi-cated. If neural regeneration appears to bepoor and the pain is significant, surgicaltreatment should proceed as discussed belowfor the painful neuroma.

TREATMENT OF PAINFULNEUROMAS

Documentation of maxillofacial pain dueto neuromas of the trigeminal nerve existsand is usually found in the setting of retainedroot tips following dental extraction, frac-tures, or direct surgical (i.e., iatrogenic) in-jury, which includes placement of plates,screws, and osteointegrative devices.11, 26

The treatment of the painful neuroma hasreceived a great deal of attention, especiallyin the extremities. An algorithm to approachthis problem has been developed based uponthe observations that painful neuromas (1)most often appear in areas where neuralregeneration is subjected to tension, move-ment, and the influence of local neurotrophicfactors, (2) have axonal regenerationthwarted by some mechanical problem, e.g.,technical misalignment of the two ends ofthe nerve, fracture site compression, or metalplate or screw interposition, and (3) are influ-enced by the microenvironment into whichthey regenerate, i.e., medullary cavity ofbone, innervated muscle, or distal nerve withintact end-organs.7’ 8, 19

If a distal nerve exists, and especially ifappropriate distal target end-organs such asthe tongue, lower lip, or cheek skin arepresent, the recommended surgical treat-ment is excision of the neuroma, whether itbe end bulb, lateral, in-continuity, or someother shape or appearance, and reconstruc-tion of the nerve gap. The usual techniquefor nerve gap reconstruction is the interpo-sition interfascicular nerve graft as describedby Millesi; the technical details are consid-ered below. In the absence of appropriate

distal tissue to reinnervate, treatment of painis best achieved by neuroma resection andimplantation of the proximal end of the nerveinto an innervated muscle or into the med-ullary cavity of bone.14 In membranous boneshaving a virtually nonexistent medullary cav-ity, an alternative is to place the proximalend of the injured nerve into an adjacentsinus, i.e., frontal sinus for the supraorbitalnerve, maxillary sinus for the infraorbitalnerve.

Recently, Gregg has reported the results ofhis treatment of painful neuromas of thetrigeminal nerve by a microsurgical tech-nique, which appears to have been a combi-nation of neurolysis, neuroma resection, andnerve repair or graft. He reported relief ofpain in about 60% of his patients whose painwas characterized by hyperalgesia or hyper-pathia.~° If a patient refuses to have autoge-nous nerve harvested for the nerve graftdonor tissue, or in the case of an iatrogenicinjury in which any additional damage isminimized, a nerve conduit of an appropriatealloplastic material is a reasonable alterna-tive. 6 Crawley and Dellon have reported sucha case for a painful neuroma of the inferioralveolar nerve.4 The use of alloplastic mate-rials in the maxillofacial region is discussedin detail in another article.

NERVE REPAIR AND NERVEGRAFTING

Nerve repair should not be mysterious.The history of nerve reconstruction is fasci-nating, and several accounts are worth read-ing.17, 24, 29 The early physicians, such as Hip-pocrates, did not distinguish nerves fromtendons. This distinction was made by Galenin the second century A.D. Nerve repair wasat first not attempted because nerve regen-eration was not considered a possibility. Par-tial nerve injury was believed to cause con-vulsions, and completing the nerve divisionwas the recommended course of action.When attempts to suture a nerve were be-gun, all types of suture material were util-ized, including thread prepared by boilingthe tendon from a turtle’s leg and then peel-ing off strands for suturing. Once it becameaccepted, in the nineteenth century, thatnerve repair was possible, the controversycentered on the source of neural regenera-tion: Did neural regeneration come from the

396 DELLON

Figure 1. The term trunk graft referred to the use of a large diameter donor nerve to reconstruct a nerve gap. Becauseof the large diameter, the revascularization of the center of the graft was poor, leading to collagenization and impededneural regeneration.

Figure 2. The term autograft refers to the donor nerve coming from the same host, and is in contrast to homograft, inwhich the donor is another member of the same species, and xenograft, in which the donor is a member of anotherspecies. These terms do not refer to the size of the graft or to the technique of placing the graft.


Figure 3. The term cable graft refers to the technique in which multiple strands of smaller cutaneous nerve are wrappedor bundled or perhaps glued into a thicker cable-like structure. The cable graft has a potential for poor revascutarizationof its central area, and is not recommended.

neuron in the spinal cord or dorsal ganglionor did regeneration occur from individualcells, parts of the distal nerve in the periph-ery? The first nerve graft, done in 1869Philipeaux and Vulpian, was done in themaxillofacial region and involved the trigem-inal nerve! Their operation was the transferof a segment of a dog’s lingual nerve intothat dog’s hypoglossal nerve.27 Their intentwas to determine if the piece of sensory nervewould reinnervate the tongue muscle, not byserving as a conduit or passive bridging ma-terial but by having the cells within it connectto the proximal and distal segments of themotor nerve. Thus Vulpian, who was a pre-eminent pathologist in Paris, was a reticular-ist and did not erhSrac6 tl~6 neuron ~0nCept.~The evolution of our current concepts ofnerve repair and regeneration has been re-viewed recently 16 and strongly supports theapproach to tension-free nerve repair, as pi-oneered by Hano Millesi. Millesi’s own re-view of his efforts to demonstrate that ten-sion at the nerve suture line produces inferiorresults by inducing increased collagen for-marion from the epineurial and perineurialfibroblasts and his courageous introductionof interposition interfascicular grafting intoclinical practice are worth reading.21

The nomenclature that is most appropriatemust be emphasized at this point and rep-resents the recommendations of the Interna-tional Microsurgery Society (see Glossary).2~

Vessels are anastomosed; nerves are repairedor reconstructed. In parts of the body inwhich the nerves are larger than they are inthe head and neck region, there are appro-priate concerns with the number of fasciclespresent. If a peripheral nerve has severallarge, identifiable fascicles, these are eachsurrounded by perineurium and separatedfrom each other with interfascicular or inter-nal epineurium. External or extrafascicularepineurium surrounds the entire group offascicles. Even though multiple small fasci-cles can be identified in, for example, theinferior alveolar nerve,31 all are sensory andonly an epineurial repair is required.5

A nerve graft requires a nerve repair ateach end of the graft. The poor prognosis ofnerve grafting following World War II camefrom the use of trunk grafts (Fig. 1). Unfor-tunately, the nomenclature for grafts hasbecome confused. Grafts taken from an in-dividual and placed into that same individualare autografts (Fig. 2), regardless of how thesegrafts are arranged or what size they are. Inthe early nerve grafting experience, graftswere often taken from other individuals (ho-mografts is the appropriate term for these),again regardless of how they were used orin what size, with the term denoting onlythe biologic source of the graft. A xenograft isa graft from a different species placed into ahuman. Clearly immunologic rejection ac-counted for these nerve graft failures. The

398 DELLON

VIENNA ~

NERVE GRAFT

Figure 4. The preferred grafting technique for a gap in a multifascicular nerve is termed an interposition interfascicularnerve graft, as described by Hano Millesi of Vienna.

trunk grafts were nerve grafts of a large cross-sectional area, such as an ulnar nerve beingused to graft a median nerve defect. It is nowclear that these grafts failed owing to insuf-ficient blood supply to the inside portions ofthe donor nerves; neural regeneration failedbecause it could not proceed through theischemic, collagenized centers of these largetrunk grafts. Some donor nerves were ob-tained from thinner cutaneous nerves, suchas the sural, but these were woven orwrapped around each other to form a "cable"(Fig. 3). Cable grafting was not successful forreasons quite similar to-those just discussed;the graft segments in the center of the cablewere not easily revascularized from the recip-ient bed.

Because the early to mid-twentieth centurynerve grafting experience was not good,nerve reconstructions were accomplished bywidely dissecting the two ends of the dam-aged nerve, flexing joints) even shorteningbone length if necessary, toward the goal ofbringing the two ends of the nerve together.Gradually, in the postoperative period, theextremity was mobilized, with scar ultimatelybeing introduced as tension was created atthe suture line. ’Controversy centered onwhether to do a primary or a secondary nerverepair. To Millesi goes the credit for proving

that placing thin cutaneous nerve segments,and multiple ones if necessary, across a de-fect in the nerve not only relieves tension atthe repair site but also ensures good vascu-larization of the grafts if they are not bundledtogether. Thus the present preferred term isan interposition interfascicular nerve graft, inwhich multiple strands are usually used (Fig.4). The principles of nerve reconstruction areillustrated with two upper extremity exam-ples (Figs. 5, 6, and 7).

RECOMMENDATIONS FORTRIGEMINAL NERVERECONSTRUCTION (APPENDIX)

Primary repair of a nerve injury should bedone whenever possible. If the ends of thenerve have been sharply divided and thereis no loss of neural tissue, a direct repair isindicated. Because the trigeminal nervebranches are usually polyfascicular andpurely sensory, a microsurgical epineurialsuture technique is best. Even if there aremultiple fascicles, the dissection required toseparate these may well cause more scarringthan it is worth. Usually two 8-0 or 9-0 nylonsutures are used, or a few more if it isnecessary to maintain orientation.


Fi-g~J~e 8.-A~- Ee~t-l~a~i~ 6f a 3S:y6a~f-01d ~d~a5 W56 7 y~.r~ b~f6re, S~ustaide~] a d~vision 5f the ulnar di~it&l deR, e to thethumb when cut in the palm with an oyster knife. She was repaired 3 weeks after the injury, and the surgeon resectedthe ends of the nerve and believed he could approximate them without "undue" tension. B, Seven years later, she haspain at the repair site that radiates into her thumb, and has no functional sensory recovery at the ulnar tip of her thumb.C, Exploration reveals a neuroma-in-continuity. D, Proximal and distal resection is required until scar-free nerve isencountered, here leaving a gap of 2.5 cm to be reconstructed when the thumb is extended. E, The anterior branch ofthe medial antebrachial cutaneous nerve is chosen as the nerve graft donor. The posterior branch, which suppliessensation to the elbow, is not taken. F, A close-up view of the nerve graft in place using two 8-0 nylon sutures at eachnerve juncture.

If the wound is grossly contaminated or ifthe mechanism of injury is such that scarringof the proximal and distal ends over the nextfew weeks is anticipated, then the ends ofthe nerve should be tagged or approximatedto each other with 3-0 nylon. One shouldplan to return for a delayed nerve repair, orpreferrably a nerve graft, when soft tissue

stabilization has occurred. Blunt, contusive,or avulsive injuries, such as gunshots ormotor vehicle accidents, may create this ex-tended nerve injury. If it is unclear whetherthe nerve is just bruised or will undergoprogressive collagenization, a nerve repairmay be done primarily, but the patient andfamily must be informed that if signs of

400 DELLON

Figure 6. A 26-year-old woman had her distal right forearm explored because of pain, thought to be ulnar nervecompression. She had had a childhood injury in that area, thought to have been of no consequence. The first explorationrevealed what the surgeon took to be a neural tumor within the ulnar nerve. A, The distal forearm incision is visible,and the sensibility evaluation demonstrated no functional sensation in her ulnar nerve distribution. B, There was wastingof her ulnar innervated intrinsic muscles, and here the clawing is noted. C, Exploration demonstrated the large neuroma-in-continuity related to the childhood injury to her ulnar nerve. Distally, the ulnar artery and the motor and sensoryfascicles of the ulnar nerve have been identified. Proximally, the dorsal cutaneous branch of the ulnar nerve has beenidentified, and it is intact. The proximal ulnar motor and sensory fascicles have been identified topographically to permitthe correct positioning of the interposition nerve grafts. D, Harvesting a long length of the medial antebrachial cutaneousnerve with its multiple anterior branches. E, The resected neuroma leaves a gap of 6 cm in the nerve to be reconstructedby the nerve graft on the gauze. F, The multiple interfascicular interposition nerve grafts in place.


Figure 7. ]’he same patient as in Figure 6, i~vith the_ technique of the graft in more detail.A, _The condition of the distalulnar nerve fascicles--soft, without scarring and appropriate for grafting. B, Similar appearance of the proximal fascicles.C, The distal nerve juncture sites. D, The proximal nerve juncture sites. E, At just 4 months after the grafting, the Tinelis advancing well, already reaching the palm.

neural regeneration do not occur, a second-ary nerve reconstruction with a graft will benecessary to restore function.

In the setting of nerve injury that is notacute, such as following dental extraction orfracture plating, the surgical planning mustbe to replace the damaged segment of nervewith a graft. Too often failure to provide atension-free reconstruction by means of agraft is the reason for failure to recover func-tion; it is not the fault of the nerve repair,but rather the choice of an inappropriatetechnique for the reconstruction.

The most appropriate source of donornerves for the maxillofacial region may notbe the head and neck! Traditionally, branchesof the cervical plexus have been used, andthese, such as the greater auricular nerve,are appropriate in length and in diameter.The disadvantage of the cervical plexus is ascar in what may be thought by the patientto be a cosmetically unacceptable site. Fur--thermore, an anesthetic ear lobe may bedisturbing to someone wearing earings. Asnoted in Figures 5, 6, and 7, the forearm,and especially the anterior branch of the

402 DELLON

medial antebrachial cutaneous nerve, canleave an acceptable donor site scar and oftenleaves very little donor site sensory disability.Although the sural nerve is probably themost commonly used donor nerve sourceworldwide, it has the disadvantage of leavinga disfiguring scar and the potential for apainful neuroma near a shoe top region. Thesural nerve is certainly a justifiable donor siteif a great deal of nerve is required in themaxillofacial region, such as for a cross-facialnerve graft for facial palsy.

SUMMARY

This article presents a brief overview of theprinciples of management of peripheralnerve injuries. The connective tissue andaxonal response to chronic compression mayresult in abnormal and painful sensory recov-ery. In more severe nerve compression or incomplete or incomplete nerve division,neural degeneration and regeneration mayoccur. Misdirected axonal sprouts may de-velop into neuromas, which may or may notbe painful. Painful compression injurieswithout neuroma formation can be managedgenerally with extraneural and intraneuraldissection as dictated by the severity of con-nective tissue scarring. Painful neuromas aretreated by excision with either reconstructionof the nerve gap or implantation of the prox-imal end of the nerve into an innervatedmuscle, medullary cavity of bone, or sinus.Finally, nerve repairs must be tension free.If necessary, an interpositional interfasciculargraft should be used to achieve a tension-free repair.

References

1. Bray GM, Aguayo AJ: Exploring the capacity of CNSneurons to survive injury, regrow axons, and formnew synapses in adult mammals. In Seil FJ (ed):Neural Regeneration and Transplantation. NewYork, Alan R Liss, 1989, pp 67-78

2. Carbonetto S: The extracellular matrix of the nervoussystem. Trends Neurosci 7:382, 1984

3. Carbonetto SD, Evans D, Cochard P: Nerve fibergrowth in culture on tissue substrata from centraland peripheral nervous system. J Neurosci 7:610,1991

4. Crawley WA, Dellon AL: Inferior alveolar nervereconstruction with a polyglycolic acid bioabsorbablenerve conduit: A case report. Plast Reconstr Surg,in press, 1992

5. Dellon AL: Discussion of "The relationship betweenstructural features of nerve trunk and suture meth-ods" by Zhong S, et al. J Reconstr Microsurg 3:91,1987

6. Dellon AL, Mackinnon SE: An alternative to theclassic nerve graft for the management of the shortnerve gap. Plast Reconstr Surg 82:849, 1988

7. Dellon AL, Mackinnon SE: Treatment of the painfulneuroma by neuroma resection and muscle implan-tation. Plast Reconstr Surg 77:427, 1986

8. Dellon AL, Mackinnon SE, Pestronk A: Implantationof sensory nerve into muscle: Preliminary clinicaland experimental observations on neuroma forma-tion. Ann Plast Surg 12:30, 1984

9. Dellon ES, Dellon AL: The first nerve graft, Vulpian,and the 19th century neural regeneration contro-versy. J Hand Surg, in press, 1992

10. Gregg JM: Studies of traumatic neuralgia in themaxillofacial region. J Oral Maxillofac Surg 48:135,1990

11. Gregg JM: Studies of traumatic neuralgias in themaxillofacial region: Surgical pathology and neuralmechanisms. J Oral Maxillofac Surg 48:228, 1990

12.Jiranec W, Seiler WA IV, Dellon AL: Teaching thetechnique for microsurgical intraneural neurolysis. JReconstr Microsurg 3:137, 1987

13.Longo FM, Manthorpe M, Skaper SD, et ah Neuron-otrophic activities accumulate in vivo within siliconenerve regeneration chambers. Brain Res 261:109,1983

14. Mackinnon SE, Dellon AL: Algorithm for manage-ment of painful neuroma. Cont Orthop 13:15, 1986

15. Mackinnon SE, Dellon AL: Classification of nerveinjuries as the basis for treatment. In Mackinnon SE,Dellon AL (eds): Surgery of the Peripheral Nerve.New York, Thieme, 1988, pp 35-39

16. Mackinnon SE, Dellon AL: Nerve repair and nervegrafting. In Mackinnon SE, Dellon AL (eds): Surgeryof the Peripheral Nerve. New York, Thieme, 1988,pp 89-127

17. Mackinnon SE, Dellon AL: Surgery of the PeripheralNerve. New York, Thieme, 1988

18. Mackinnon SE, Dellon AL, Hudson AR, Hunter DA:A primate model for chronic nerve compression. JReconstr Microsurg 1:185, 1985

19.Mackinnon SE, Dellon AL, Hudson AR, Hunter DA:Alteration of neuroma formation by manipulation ofneural enviro~a~ent. Pla_st~ Reconstr Surg 76:345,1985

20. Mackinnon SE, O’Brien JP, Dellon AL, et al: Anassessment of the effects of internal neurolysis on achronically compressed rat sciatic nerve. Plastconstr Surg 81:251, 1988

21. Millesi H: The nerve gap. Theory and clinical prac-tice. Hand Clin 2:651, 1987

22. Millesi H, Terzis JK: Nomenclature in peripheralnerve surgery. Clin Plast Surg 11.3-8, 1984

23. Zachary LS, Dellon AL: The bands of Fontana, in.preparation, 1992

24. Ochs S: A brief history of nerve repair and regen-.eration. In Jewett DL, McCarroll HR Jr (eds): NerveRepair and Regeneration. St. Louis, CV Mosby,1980, pp 1-8

25. Omer GE Jr, Spinner M: Management of PeripheralNerve Problems. Philadelphia, WB Saunders, 1980

26. Peszkowski MJ, Larsson A: Extraosseous and in-traosseous oral traumatic neuromas and their asso-ciation with tooth extraction. J Oral Maxillofac Surg48:963, 1990


27. Philipeaux JM, Vulpian A: Note sur des essais degreffe d’un troncon du nerf lingual entre les deuxbouts du nerf hypoglosse, apres excision d’un seg-ment de ce dernier nerf. Arch Phys Norm Pathol3:618, 1870

28. Richardson PM, Issa VMK, Aguayo AJ: Regenera-tion of long spinal axons in the rat. J Neurocytol13:165, 1984

29. Snyder CC: The history of nerve repair. In Omer GEJr, Spinner M (eds): Management of PeripheralNerve Problems. Philadelphia, WB Saunders, 1980,pp 353-364

30. Sunderland S: Nerve and Nerve Injuries, ed 2.Edinburgh, Churchill Livingstone, 1978

31. Svane TJ, Wolford LM, Milam SB, Bass RK: Fascic-ular characteristics of the human inferior alveolarnerve. J Oral Maxillofac Surg 44:431, 1986

32. Thoenen H, Edgar D: Neurotrophic factors. Science229:238, 1985

33. Waller AV: Experiments on the glossopharyngealand hypoglossal nerves of the frog and observationsproduced thereby in the structure of their primitivefibres. Phil Trans R Soc London 140:423, 1850

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management of peripheral nerve...

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