Chir. plastica (Berl.) 3, 165--174 (1976) �9 by Springer-Verlag 1976

The Use of Neuromuscular Free Autografts with Microneural Anastomosis to Restore Elevation

to the Paralysed Angle of the Mouth in Cases of Unilateral Facial Paralysis

W i t h an A n a l y s i s of L a t e Resu l t s of Muscle Gra f t s in t he T r e a t m e n t o f 103 Cases of F a c i a l H e m i p a r e s i s *

Noel Thompson and E. H. Gus tavson

The Middlesex Hospital, London and Mount Vernon Centre for Plastic Surgery, Northwood, Middlesex, England

Received August 25, 1975

Summary. A new method is described for the correction of paralysis of the elevator muscles of the angle of the mouth in cases of unilateral facial paresis, by transplanting skeletal muscle as a free graft together with its motor nerve of supply, the latter being anastomosed to normal filaments of the facial nerve on the uninvolved side of the face, using micro- surgical technique. The results in twelve patients treated over a period of one year, are encouraging and are being given continuing trial.

The late results of free autogenous skeletal muscle grafts in restoring movement to the eyelids and mouth regions in 103 cases of unilateral facial paralysis, involving 157 grafts, are presented.

I n pa t ien t s suffering from uni la te ra l facial para lys is , weakness or absence of v o l u n t a r y ac t i v i t y in those muscles concerned wi th e levat ion of the angle of the mou th on smil ing (zygomat icus ma jo r and minor, l eva tor angul i oris, and leva tor labii superioris muscles) cons t i tu tes a chief source of complain t , and no t infre- quen t ly persis ts in the presence of a funct ioning oral sphincter . Transpos i t ion of pedicled muscle flaps f rom homola te ra l masse te r and t empora l i s muscles have fai led to achieve general use, and being i nne rva t ed b y the m o t o r divis ion of the t r igemina l nerve can a t bes t only resul t in a bizarre and unco-o rd ina ted move- ment . The use of sural nerve graf ts , employing a microsurgical technique, to l ink zygomat ic and buccal f i laments of the facial nerve on the two sides of the face (Smith, 1971 ; Ander l , 1973), can only be app l ied in cases of un i la te ra l para lys is of recent onset and before degenera t ion of the pa ra lysed muscles has become establ ished. Fre i l inger (1975) has ingeniously ex tended this me thod to allow app l ica t ion to longs tanding facial para lys i s by first inser t ing a cross-face nerve gra f t su tu red to normal facial nerve f i laments a t one e x t r e m i t y and left free a t i ts opposi te end on the pa ra lysed side; seven mon ths l a te r the free end of the nerve graf t was i m p l a n t e d into a newly t r a n s p l a n t e d skeletal muscle graf t , inser ted on the pa ra lysed side of the face, which then became re inne rva ted .

I t has now been r epea ted ly conf i rmed t h a t a free au tog ra f t of skele ta l muscle m a y be t r a n s p l a n t e d successfully p rov ided i t is dene rva t ed two weeks earlier,

* Presented at Round Table on Facial Palsy: Sixth International Congress of Plastic and Reconstructive Surgery, Paris, France, 25 August 1975.

166 N. Thompson and E. H. Gustavson

t ransfer red in i ts ent ire volume, becomes vascular ized by direct anas tomosis of i ts vessels wi th those in the host bed, and is given access to re innerva t ion by the ingrowth of cont iguous mo to r nerve axons (Thompson, 1971). Such axonal invas ion is usual ly from the normal muscle wi th which the graf t is placed in d i rec t contact , bu t can resul t f rom imp lan t a t i on of the centra l end of an ad jacen t mo to r nerve. I n the me thod descr ibed below a fr.ee graf t of skeletal muscle is t r a n s p l a n t e d as a composi te neuromuscular graf t with i ts motor nerve of supply in con t inu i ty with the graft , and re innerva t ion is ensured by direct anastomosis of i ts nerve with normal f i laments of the facial nerve, employing a microsurgical technique, to restore the movemen t of e levat ion to the pa ra lysed angle of mouth . Vascular iza t ion is by di rec t anas tomosis of vessels of the graf t with those in the t issues of the host bed in which the graf t is laid.

Technique (Fig. 1)

The extensor d ig i torum brevis muscle of the foot is dene rva ted by division of the anter ior t ib ia l n e r v e a t a level 7.5 cms above the ankle joint . This is com- p le ted under pneumat i c tou rn ique t wi th exsanguina t ion of the l imb, and using a nerve s t imula to r accura te ly to locate the nerve. Bed rest for 5 days after- wards, wi th l imi ted ac t i v i t y thereaf te r is advisable to faci l i ta te dissect ion a t the sec- ond s taged opera t ion 14 days later .

Fig. 1. Diagrammatic illustration of a composite neuromuscular graft of extensor digitorum brevis muscle of the foot, sutured to the paralysed zygomaticus muscles and suspended by slinging its tendon from the zygomatic arch above. Its motor nerve in continuity is given microsurgical suture of its constituent fasciculi to two filaments of the buccal branch of the

facial nerve of the unparalysed side

Neuromuscular Free Autegrafts in Unilateral Facial Paralysis 167

Two weeks after denervation, again using a pneumatic tourniquet, the extensor digitorum brevis muscle is removed, carefully preserving its at tached nerve (distal to the level of section) and tendons in continuity with the muscle graft. The muscle bellies are carefully cleansed of all fat, fascia and ligamentous material, the individual motor nerve branches to each belly identified, and using micro- dissection one or two bellies selected and their associated nerve fasciculi dissected from the main nerve trunk.

On the face, bilateral incisions in the nasolabial skin crease are made, ex- tending from just below the alar base of the nose to 1 cm below the level of the angle of the mouth. On the paralysed side the non-functional and degenerated zygomaticus and levator anguli oris muscles are exposed, and the muscle graft sutured into this f ibro-fatty bed, being firmly at tached to the modiolus at the angle of mouth below, with its tendon passed subcutaneously upwards to be slung, firmly fixed by locking sutures, to the zygomatic arch exposed through a small preauricular incision. By blunt dissection a subcutaneous track is prepared across the full width of the upper lip, joining the two nasolabial incisions and the motor nerve fibres supplying the muscle graft drawn by careful traction through this tunnel to present in the wound on the opposite (unparalysed) side of the face. On the contralateral (normal) side of the face, the nerve plexus of branches of the buccal portion of the facial nerve is exposed by microdissection, and those filaments supplying the levator anguli oris and zygomaticus muscles identified by electrical stimulation. Two or three of these are divided, and their central ends submitted to microneural anastomosis by a single non-absorbable suture (Ethilon 10/0) to the individual fasciculi of the motor nerve of the muscle graft. Both facial wounds are then sutured with drainage for 48 hours, and firm elastoplast pressure dressings maintained for 5 days.

Results

During the past year twelve patients have been treated in this way. Of these the first two received prolonged operations while the technique was being estab- lished, and were complicated by post-operative infection with resultant major loss of graft. Four patients treated within the last six months are still in process of reinnervating their muscle grafts, but of the residual six patients operated on more than six months ago, five show progressive reinnervation of grafts with varying degrees of restoration of the voluntary movement of elevation to the angle of the mouth on the paralysed side. All show continuing improvement up to the present time. As an example may be cited the following patient:

Case J. C. (No. 120395) (Fig. 2). Male. Age 35. An Ital ian hairdresser, he suffered at left sided Bell's palsy five years earlier, with minimal recovery except in sphincteric activity of the mouth. His chief complaints related to the eyelid paralysis (epiphora, conjunctivitis, blepharitis etc.) but more particularly to facial asymmetry especially marked on smiling due to complete loss of voluntary elevation of the left angle of mouth.

Following preliminary denervation of the extensor digitorum brevis muscles of both feet, two weeks later both sets of muscle grafts were transplanted to the face, one to the eyelids (where its application to the orbicularis oculi muscle

168 N. Thompson and E. H. Gustavson

Fig. 2a--d. Case. J. C. Male. Age 35. Unresolved Bell's palsy of left face of 5 years' dura- tion, treated by neuromuscular free graft of extensor digitorum brevis muscle and anterior tibial nerve, with microneural suture to facial nerve filaments on the unaffected (right) side of face. (a) Pre-operative: at rest. (b) Pre-operative: on smiling, showing major loss of eleva- tion of left angle of mouth. (e) Post-operative, 6 months: at rest,. (d) Post-operative,

6 months: on smiling. Facial animation largely restored

of the normal side, and passage of the graf t tendons th rough pos tnasa l vein graf ts to be inser ted along the margins of the pa ra lysed eyelids, y ie lded a good resul t wi th complete vo lun t a ry closure of the eyelids) and one into the mouth region with microneura l anas tomosis of two fasciculi of the graf t motor nerve to two buccal f i laments of facial nerve on the unpa ra lysed side of the face. Af ter six months the resul t in the mou th region is i l lus t ra ted (Figs. 2 c, d) with v i r tua l ly normal movement s of the lips dur ing condi t ions of o rd ina ry facial animat ion.

Discussion

Fol lowing the exper imenta l work of T a m a i et al. (1970) in t r ansp lan t ing muscle graf ts in dogs, using microsurgical anas tomosis of both muscles and nerves, i t

Neuromuscular Free Autografts in Unilateral Facial Paralysis 169

must appear tha t the transplantation of a muscle belly with its associated nerve, ar tery and vein, to the face with a view to restoring elevation to the paralysed angle of mouth by microsurgical anastomosis of both vessels and nerve to facial vessels and nerves on the normal side, is probably technically possible: yet the failure rate from vascular thrombosis would seem likely to prove a serious complication. Vascularization of free grafts of skeletal muscle only, routinely transplanted to the face occurs in at least 90% of grafts, so that the technique described above depends for success almost entirely upon a relatively simple microsurgical anastomosis of nerves 0n!y.

The method eliminates the prolonged t reatment period and multiple staged operations involved when the muscle graft and the nerve graft are inserted at widely separated intervals, as described by Freilinger (1975). I t is of interest to consider why a free muscle graft t ransplanted following preliminary denerva- tion, together with its nerve of supply which is then given microneural anasto- mosis to local facial nerve filaments on the opposite side of the face , should be able to survive the period required for axonal regeneration to traverse a distance of 8-10 cms to produce reneurotization of the muscle fibres, without the latter having undergone irreversible fibrosis first. I t is probable tha t a number of factors are concerned, of which the following may be of significance.

1) I t is known tha t if a frde muscle graft can survive the initial period of 3-4 days total ischaemia following transplantation, then reinnervation may be delayed for several months without muscle fibre degeneration being complete. Preliminary denervation assists survival of the muscle graft by reducing the metabolic demands of white skeletal muscle as well as by increasing its vasculari- zation (Hogan et al., 1965; Romanul and Hogan, 1965).

2) I t is also known tha t axonal regeneration is more effective in the presence of preliminary denervation. Gutmann (1942) found tha t when the rabbit ' s sciatic nerve was crushed twice at intervals 16-42 days apart , axonal regeneration was significantly more rapid than after a single crush. This suggested tha t the im- proved regeneration might be due to an increase in the number of Schwann cells accessible to the regenerated nerve fibres in the nerve distal to the lesion.

3) Lieberman (1971) states that during the first week after nerve injury the protein synthetic machinery of traumatized neurons, as indicated by morpho- logical and biochemical criteria, is in disarray; over the next week this machinery reorganises and may hyper t rophy to such a degree tha t the protein content may be doubled. Ducker et al. (1969) have suggested that axonal outgrowth would proceed faster after a second nerve lesion than after the first if there were an interval of 2 to 3 weeks between the two lesions, and this has been practically confirmed experimentally by Me Quarrie and Grafstein (1973): these investigators found tha t in the sciatic nerve of adult mice, the rate of axonal regeneration following nerve excision was increased by 27 % if preliminary denervation by nerve crush had been carried out 2 weeks earlier.

Where the mouth lacks sphincteric act ivi ty in addition, a routine circum- oral muscle graft of palmaris longus muscle is carried out s imultaneously--as also is muscle grafting of paralysed eyelids where these are present, as in the case illustrated above.

170 N. Thompson and E. H. Gustavson

The Late Results of Muscle Grafts in the Treatment oi Unilateral Facial Paralysis

Free grafts of skeletal muscle are known to survive as free grafts, provided they are denervated two weeks before transfer, are t ransplanted as intact muscle bellies to preserve full fibre length, and are placed in contact with normal, fully vascularized and innervated .muscle at the recipient site (Thompson, 1971). Their use in the t rea tment of unilateral facial paralysis, to restore movement to the paralysed eyelid or mouth has been fully described (Thompson, 1974). During the period 1968-1975, 103 patients suffering from unilateral facial para- lysis, in all of whom the paralysis had been present for at least one year, have been t reated in this way (Table 1). Results have been classified as " g o o d " where muscular act ivi ty was restored to essentially normal levels and symptoms completely relieved, " sa t i s fac to ry" where the restored movements lacked only a few millimetres of normal range and symptoms were significantly improved, and " u n i m p r o v e d " where no benefit resulted. Of a total of ~57 sets of muscle grafts applied to eyelid and mouth regions, " g o o d " or " sa t i s fac to ry" results were obtained in 88%, and 12% were unimproved.

Table 1. Muscle grafts to unilateral facial paralysis 1968-1975

Patients treated Grafts to eyelids only 12 cases Grafts to eyelids and mouth 54 cases Grafts to mouth only 37 cases

Total cases treated 103

No. of grafts Good Satisfactory Unimproved

Comprehensive results Muscle grafts to paralyzed eyelids 66 34 28 4 Muscle grafts to paralyzed mouth 91 53 23 15

Total grMts 157 87 (55.4%) 51 (32.5%) 19 (12.1%)

Paralysed Eyelids (Table 2) Two methods have been applied, and the muscle selected for t ransplantat ion

to the orbital region was the extensor digitorum brevis muscle of the foot in all cases except one (where the pronator teres muscle of the forearm was used).

a) Muscle Gra/t Applied to the Temporalis Muscle of the paralysed side, and the graft tendon taken in continuity, inserted subcutaneously along the margins of the paralysed eyelids to be anchored to the medial palpebral ligament. Re- innervat ion of the muscle graft is from the motor division of the trigeminal nerve supplying the temporalis muscle, so tha t closure of the eyelids occurs on biting the teeth together. The appearance is therefore rather bizarre, but corneal protection and relie~ of symptoms can be routinely obtained, as in the four patients treated. The method is reserved for elderly patients where appearance

Neuromuscular Free Autografts in Unilateral Facial Paralysis

Table 2. Muscle grafts to unilateral paralyzed eyelids 1968-1975

171

Total cases treated 66 Age 6 to 74 yaers

Muscles used as free grafts Extensor digitorum brevis M. (foot) 65 Pronator teres M. (forearm) 1

Result Graft recipient site Good Satisfactory Unimproved

Temporalis M. 4 0 0 Orbicularis oculi M. 30 28 4

34 (51.5%) 28 (42.4~163 4 (6.1%)

Complications Graft absorption 3 Tendon necrosis 5

(inside silicone sheath) Infection (of tendons 3

in silicone sheath) il (16.6%)

Secondary operations Tenolysis and/or tightening of tendons 14 Replacement of absorbed muscle graft 3 Replacement of tendon grafts 5 Retropunctal cautery to conjunctiva 3

25 (37.8%)

Fig. 3a and b. Muscle grafts of extensor digitorum brevis muscles of the foot applied to the homolateral temporalis muscle in a frail 67 year old woman suffering from unresolved right sided Bell's palsy with onset at age 11 years. (a) Pre-operative: eyes closed. (b) Post- operative, 1 year after muscle grafting and insertion of skin graft to lower eyelid to relieve

ectropion: on biting the teeth together. All symptoms completely relieved

is of secondary impor tance , to relieve phys ica l d iscomfor t by a simple, s t ra igh t - fo rward opera t ion (Fig. 3).

b) Muscle Gra/t Applied to the Contralateral (Normal) Orbicularis Oculi Muscle, and the t endons in con t inu i ty passed behind the nasa l bones and subcu taneous ly along the margins of t he pa ra ly sed eyelids to be anchored to the i r l a te ra l pal- pebra l l igament . I n the ea r ly cases t r e a t e d the tendons of t he graf t were enshea thed in silicone sheet where t hey passed behind the nasa l bones and an te r io r

172 N. Thompson and E. H. Gustavson

Fig. 4. Muscle grafts of extensor digitorum brevis muscles, applied to orbicularis oculi mueles of the normal eyelids and their tendons inserted into the margins of the paralysed eyelids after traversing vein grafts lying on nasal mucosa behind the nasal bones. Patient was a woman, age 66, suffering from complete right facial paralysis two years after removal of an acoustic neuroma. (a) Pre-operative: at rest. (b) Pre-operative: on voluntary closure of eyelids. (c) Post-operative, at 1 year: at rest. (d) Post-operative, at 1 year: on voluntary

closure of eyelids. Complete loss of all eye symptoms of epiphora and irritation

to nasal mucosa. These silicone tubes resulted in a high incidence of infection and tendon necrosis, and have been discarded in favour of autogenous vein grafts

as advoca ted by Hakel ius (1974). Since this modif icat ion in technique, com- plicat ions have been great ly reduced, and the results improved correspondingly

Neuromuscular Free Autografts in Unilateral Facial Paralysis 173

(Fig. 4). Of the 62 patients treated, " g o o d " or "sa t i s fac tory" results have been obtained in 94%. Secondary operations were required to ~djust the tendons of the grafts, or free them from adhesions at their post-nasal site, in 14 cases (22.6%). In three patients where epiphora was unrelieved because tension on the tendons of the grafts during eyelid closure removed the lacrimal punctu.m of the lower eyelid from contact with ocular conjunctiva, retropunctal cautery to the eyelid conjunctiva produced a sufficient entropion of the lower eyelid to cure the condition.

The Paralysed Mouth, has been treated in 91 patients, with particular refer- ence to restoring two movements.

a) Sphincteric Contraction o/ the Orbicularis oris. The muscle graft used was usually the palmaris longus of the forearm (40 patients) when the muscle belly was split so as to completely encircle the lips subcutaneously. In 14 patients where no palmaris longus muscle was available, the extensor digitorum brevis muscle of the foot was used, in association with the plantaris (or an extensor digitorum longus) tendon which was used to sling the muscle graft up to the zygomatic arch to give static support to the paralysed side of the face. Of the 54 patients so treated, 49 (90.7%) yielded " g o o d " results and 5 (9.3%) were "sa t is factory" . No cases were unimproved. Secondary tightening of the tendon sling to the zygomatic arch was applied in 9 cases (16.7%) to improve the position of the paralysed mouth at rest.

b) Elevation o/ the Paralysed Angle o/ Mouth. Where voluntary activity in the muscles responsible for elevation of the angle of the mouth (zygomaticus, levator anguli oris, levator labii superioris) on the paralysed side, still partially survives, then the movement can be strengthened and reinforced by applying a muscle graft to the weakened zygomaticus muscles on the paralysed side. In 18 patients treated in this way, " g o o d " results were obtained in 4 and "satis- fac tory" in 10; 4 patients were unimproved. The results are best when the degree of partial paralysis present pre-operatively is not profound.

Where there is total paralysis of the elevators of the angle of the mouth, a t tempts have been made to restore movement by applying the palmaris longus muscle as a free graft to the zygomaticus muscles of the normal (unparalysed) side, while passing its associated tendon in the substance of the upper lip and through a separate small tendon loop slung from the zygomatic arch on the paralysed side to end in an a t tachment to the paralysed angle of mouth. I t was hoped tha t contraction of the palmaris longus muscle graft, on reinnervation, would be transmit ted via its tendon to restore movement to the paralysed angle of mouth, but results have been poor in the 19 patients treated (minimal impro- vement in 8, failure in 11) and the method has been abandoned in favour of the neuromuscular composite graft with microneural anastomosis, described above.

References Anderl, H. : Reconstruction of the face through Cross-Face-Nerve Transplantation in facial

paralysis. Chit. plastica 2, 17 (1973) Ducker, T. B., Kempe, L. G., Hayes, G. J. : The metabolic background for peripheral nerve

surgery. J. Neurosurg. 80, 270 (1969) Freilinger, G.: A new technique to correct facial paralysis. Plast. reconstr. Surg. 56, 44

(1975)

174 5/. Thompson and E. H. Gustavson

Gutmann, E. : Factors affecting recovery of motor function after nerve lesions. J. Neurol. Psyehiat. 5, 81 (1942)

Hakelius, L.: Transplantation of free autogenous muscle in the treatment of facial para- lysis. Scand. J. Plast. reeonstr. Surg, 8, 220 (1974)

Hogan, E. L., Dawson, D. M., Romanul, F. C. A. : Enzymatic changes in denervated muscle. II. Biochemical Studies. Arch. Neurol. (Chic.) 18, 274 (1965)

Lieberman, A. R.: The axon reaction. A review of the principal features of perikaryal responses to axon injury. Int. Rev. Neurobiol. 49, 124 (1971)

McQuarrie, I. G., Grafstein, B.: Axon outgrowth enhanced by a previous nerve injury. Arch. Neurol. (Chic.) 29, 53 (1973)

Romanul, F. C. A., Hogan, E. L." Enzymatic changes in denervated muscle. I. Histochemical Studies. Arch. Neurol. (Chic.) 13, 263 (1965)

Smith, J. W.: A new technique of facial animation. Trans. Fifth Internat. Congr. Plast. Reconstr. Surg. London: Butterworths 1971, p. 83

Tamai, S., Komatsu, S., Sakamoto, H., Sano, S., Sasauchi, N., Hori, Y., Tatsumi, Y., Okuda, H. V. : Free muscle transplants in dogs with microsurgical neurovascular anas- tomoses. Plast. reconstr. Surg. 46, 219 (1970)

Thompson, N. : Investigation of autogenous skeletal muscle grafts in the dog. With a report on a successful free graft of skeletal muscle in Man. Transplantation 12, 353 (1971)

Thompson, N. : A review of autogenous skeletal muscle grafts and their clinical applications. Clin. Plast. Surg. 1, 349 (1974)

Noel Thompson, M. S., F.R.C.S. The Middlesex Hospital London/England