SELECTIVE NEURECTOMIES TO ACHIEVE SYMMETRY IN PARTIAL AND COMPLETE FACIAL PARALYSIS

Transcription

1 British Journal of Plastic Surgery (I976), 29, SELECTIVE NEURECTOMIES TO ACHIEVE SYMMETRY IN PARTIAL AND COMPLETE FACIAL PARALYSIS By L. CLODIVS, M.D. Plastic Surgery Section, Second Surgical Department, University Hospital, Zurich, Switzerland THE goal of surgery for facial palsy when nerve reconstruction is not possible is the restoration of symmetry at rest and in function. Static symmetry is not so difficult to achieve but dynamic symmetry is still the ideal to be aimed for. In the patients to be described this was their first prerogative to be obtained even at the expense of the intensity of movement in the unaffected side, which in any case produces bizarre grimaces when emotions should be displayed. This paper describes the technique and the results obtained by selective neurectomies of the unparalysed facial nerve in partial and total facial palsy. This procedure has been advocated before (Bell, i82i; Marino, x953) but is not much in use today, since the great regenerative ability of the facial nerve seems to prevent a predictable and lasting result. By much more radical resections than previously thought necessary, however, permanently acceptable dynamic symmetry may be obtained in partial cases and less distortion of expression in complete palsies. From I968 to November I973, 35 selective neurectomies for partial and for total facial palsy have been carried out. PARTIAL FACIAL PALSY Operative technique. In order to achieve permanent exclusion of a relatively hyperactive muscle group, all its supplying nerve branches must be radically resected. This necessitates a very complete exposure of the facial nerve serving the area. Using as a vasoconstrictor POR 8 in a dilution of I ml per 20 ml of saline, a dry operative field is obtained (Clodius and Smahel, z97o). The skin incision is situated anterior to the external ear, then curves forward, parallel to the crease lines and 2 cm below the inferior mandibular margin, to end in front of a line to the anterior edge of the masseter muscle. The lower part of the incision is unnecessary for exposing the frontal branches. Using as a guide the inferior wall of the auditory meatus and the mastoid process (McCormack et al., I945; Flynn, I96O; Furnas, I965) the trunk of the facial nerve is identified prior to its entry into the parotid gland. In continuing the complete dissection of the nerve branches throughout their course in the gland, it must be remembered that the branches do not run in a flat plane; it is important therefore to free the main branches and look for ramifications in a deeper plane. The branches to the muscles to be denervated or left intact 'are identified by bipolar faradic stimulation. Because nerve conduction diminishes with repeated stimulation, the lowest current intensity which will contract the muscle is selected on the stimulator. Many small anastomotic connections are encountered between the thicker nerve branches (Fig. I). All these communicators are excised. Next, the branches at the periphery, distal to the parotid gland, leading towards the area to be denervated, are identified. For documentation, result control and accurate selection, they are usually outlined and numbered on a piece of sterile paper, with the location and the type of their muscle response. The nerves chosen for elimination are excised for a distance of at least 2 cm and up to their origin 43

2 44 BRITISH JOURNAL OF PLASTIC SURGERY FIG. I. From T. Fujita. Dissection of a left facial nerve. It took the author one full month to perform the anatomical preparation and the drawing. The abundance of communicating nerve branches, both in the parotid and in the postparotid (muscle) area is impressive. from a centrally preserved trunk. It is important to overcorrect; the neighbouring muscles to a hypercontractile area must also be weakened. Prior to wound closure, the remaining facial nerve stems are stimulated for final control. The wound is closed in layers with suction drainage through 2 or 3 catheters which leave the wound through the scalp; if parotid secretion should persist after removal of the drains, it will stop by itself as the upward directed tract contracts. A well-contoured pressure dressing is applied and the patient is given a liquid diet for 3 days, in order to limit further motion to the operative area. Nasolabial area. To obtain complete denervation of the nasolabial area is difficult and 2 of 8 such patients required re-operation. Nerve trunks, innervating both the levator oris and the lip closing muscles, had to be dissected quite distally to their ramifications for each muscle group. Figure I delineates the abundance of nerve fibres in this area and the many nerve connections between the orbicularis of the lower eyelid and the nasolabial area as well as between branches to the lower lip, the nasolabial area and the platysma.

3 NEURECTOMIES IN PARTIAL AND COMPLETE FACIAL PARALYSIS 45 FIG. 2. A, Congenital partial facial palsy of the middle third of the left face, preoperative view. B, Postoperatively, the patient tries to elevate both nasolabial areas. The right upper lip is slightly lower than the left. In the patient shown in Figures 2 and 3 almost complete symmetry was obtained except for a moderate lowering of the upper lip. Denervation on the active right side and a temporalis transfer to the eyelids on the left was carried out simultaneously to the patient shown in Figure 4. Two months later, when showing her teeth is attempted, the necessary overdenervation is obvious but after a year, on smiling, the improved symmetry of expression is visible. In retrospect, a better result would have been obtained by total denervation of the right quadratus labii superioris and zygomaticus, while preserving function of the buccinator and risorius muscles. Lower lip. Five patients have been operated on for asymmetry of the lower lip with permanent improvement. A typical case of congenital partial paralysis is shown in Figures 5-7. It is interesting that his father had a similar palsy but on the left side of his lip. This condition has been described as "asymmetric crying facies" (Pape and Pickering, 1972) or congenital absence of the depressor anguli oris muscle (Nelson and Eng, 1972). The elimination of the nerve supply to the lower lip needs extensive dissection of additional nerve fibres. To obtain the result shown in Figure 7, 8 peripheral facial branches were excised. To the patient, satisfactory symmetry was obtained. On close

4 6 BRITISH JOURNAL OF PLASTIC SURGERY FIG. 3. Intra-operative stimulation of patient in Figure 2. A, Upper main stem of facial nerve, distal to the branches for forehead motion. There is contraction of eyelids (observe the fine folds in contrast to C and D), of the corrugator, of various heads of the quadratus labii superioris and of the zygomaticus, caninus, risorius and buccinator muscles (fold below nasolabial fold, seen again in B). B, Communicating branches and some branches to the quadratus labii superioris have been removed, but further resection is necessary because the muscle response is still excessive. C and D, Larger mandibular branches: that producing the contractions in C has to be removed, while the branch innervating mainly the triangularis (D) is left intact. E, Stimulation of remaining branches to check lid closure and wrinkling of forehead (arrows). FIG. 4. A, Congenital left partial facial paralysis in a patient with additional anomalies of the genitourinary system. B, Three weeks following denervation of muscles to the right nasolabial fold. The nose was shortened in a separate procedure. The patient is trying to produce maximum movement in both cheeks. C, One and a half years postoperative: partial reinnervation on the right and improved symmetry in the perioral area.

5 NEURECTOMIES IN PARTIAL AND COMPLETE FACIAL PARALYSIS 47 FIG. 5. Congenital absence of the right depressor anguli oris muscle. Lid closure is slightly weaker on the left side. inspection of the photographs however, the nasolabial fold appears flatter on the left and the right lower lip is more activated. Figure 8 shows a minor asymmetry of the lower lip. To my mind the indication for operation which the patient insisted on, was debatable. The patient however was satisfied with the result, although there is some overcorrection. Frontal area. Denervafion of the frontal area necessitates finding all branches to this site, including those which stimulate the medial fibres of the frontalis muscle (Figs. 3 and 6). Two patients have been operated on with satisfactory results. TOTAL UNILATERAL FACIAL PALSY The problem of weakening the sound side is discussed with the patient. He is informed that initially after operation, his operated side will be almost completely paralysed and that he may not be able to close his eye for 3 to 4 months, since overcorrection, as in partial facial palsy, is mandatory. The surgical technique is as described

6 48 BRITISH JOURNAL OF PLASTIC SURGERY FIG. 6. Intraoperative facial stimulation of patient in Figure 5- A, A large branch to the lower lip and the nasolabial area. B, Following further dissection, a branch to the lower lip is isolated which curls and lowers the lip without raising the upper lip. This branch is resected. C, Further dissection reveals a branch to the quadratus labii inferioris, the triangularis and to a part of the platysma. This branch is resected. D, There is still a branch for depressing the corner of the mouth, as compared to E. This branch needs to be removed. Note contraction of the forehead corrugator. E, Subsequent to resection of 8 facial nerve branches to the lower lip, the response of stimulation of the central nerve stem is visible. Compare the innervation pattern of the lower lip and of the nasolabial fold with A. Note (arrow) contraction of medial fibres of the frontalis. FIG. 7. Patient of Figures 5 and 6. Result 2I months after nerve resections. A, On forced lip closure; B, on grimacing; C, on smiling.

7 NEURECTOMIES IN PARTIAL AND COMPLETE FACIAL PARALYSIS 49 FIG. 8. A and B, Pre- and postoperative (IO months) condition in minor asymmetrical innervation of the lower lip. 29/I--D

8 5 BRITISH JOURNAL OF PLASTIC SURGERY FIG. 9. A, Total right facial palsy, subsequent to removal of an acoustic neuroma, I week postoperatively. Anastomosis of the facial with the hypoglossal nerve had been carried out providing some muscle tonicity but no complete lid closure. B, One and a half years following selective denervations on the left and following static and "dynamic" suspensions on the right. On the left, the patient is forcedly elevating his cheek. for partial facial palsy: very extensive exposure of the facial nerve, starting with the fibres of the inferior mandibular branch, removal of small communicating branches, and minimum stimulation in order not to fatigue the nerve. I usually leave one branch for lid closure and one or two branches for reduced movement in the oral area. The ability to elevate the nasolabial area (zygomaticus, quadratus labii superioris and caninus muscles) is excluded. By preserving reduced action of the orbicularis oris, some function for the elevators and depressors of the oral commissure will return. Usually the denervation procedure is combined with static support and other procedures on the paralysed side. Of I5 patients, only I had a second denervation procedure. In this group therefore there was general satisfaction even when at the beginning of our experience the elimination of motion was not as radical as seen in Figure 9. Whenever, after too conservative denervation, movement returned, this occurred within z to 3 months. DISCUSSION R e c u r r e n c e o f m u s c l e action a f t e r d e n e r v a t l o n. In an early case because of unilateral forehead paralysis following a face lift, a neurectomy on the normal side

9 NEURECTOMIES IN PARTIAL AND COMPLETE FACIAL PARALYSIS 5I was performed using the technique of doubling the nerve end over itself (Fackelman and Clodius, I972), through a peripheral incision between the lateral eyebrow and temporal hair line (Furnas, I965). Symmetrical paralyses resulted. Within 2 months, however, movements began in the denervated paramedian supraorbital area, to which the arrow in Figure 6 points. From there, return of motion spread gradually in a centrifugal pattern. From the findings in the literature on collateral nerve regeneration (Weiss and Edds, I945; Edds, I953; Wohlfahrt, I958; Battle, I963), from the fact that all muscles of expression develop from the same mesodermal mass (Futamura, I9o6), and from the peripheral anatomy of the facial nerve, it appears that the recovery of the frontalis muscle was not by axon regeneration (Gutman and Young, I944) of the resected temporal facial branches, but by collateral regeneration: branching and sprouting of peripheral nerve fibres from intact muscles into the neighbouring denervated muscle. In addition the time in which movement of denervated muscles recurred is consistently short while, when the main facial stem is sectioned and resutured, regeneration takes I2 to I8 months (Battle, I963; Sunderland, I97o; Gaster et al., I97I). Furthermore, the most frequent recurrences were in the nasolabial area, which lies between muscles with intact nerves. Finally, it is difficult to conceive how a central nerve stump can consistently find its way across at least 2 cm of scar, to its distal branch, when complete return of function after facial nerve grafting, using microsurgical techniques, is achieved in only about 50 per cent of cases (Conley, 1973). The unused facial nerve endings. In view of the recent introduction of cross face nerve grafting (Smith, I97I; Anderl, I973) it would seem worthwhile to use the proximal cut ends to supply movement in this way in cases of total paralysis. At present, in all cases of total unilateral palsy, usually following a temporalis transfer to the paralysed eyelids, the facial nerve is exposed at its entrance into the parotid gland through the elongated incision in front of the ear for direct stimulation. This is done, even when preoperative electro-myography shows signs of degeneration and no percutaneous faradic excitability, since some muscle contractions have been observed on direct stimulation of the facial nerve in the presence of both these findings and even in a palsy of 9 years' duration. If minor motion of muscles on direct stimulation results, cross face nerve grafting using the sural nerve is performed, using the central nerve endings made available by the denervation procedure on the normal side. Funicular suturing (Gutmann and Young, I944; Sunderland, I97o), with the aid of magnification, is done. The grafts measure approximately cm. The results will be published after an adequate follow-up period has elapsed. SUMMARY Experience with selective facial neurectomies, in partial and total palsies, is reported. If under careful control by faradic stimulation the area to be weakened is completely, and the neighbouring musculature partly denervated, consistently satisfactory results can be predicted. Evidence suggests that rather than recovery of motion by axon regeneration, there is a marked tendency for collateral regeneration of peripheral facial nerve fibres from muscles left intact, into denervated muscles. Itis a pleasure to acknowledge the ever ready assistance provided by Mrs E. Jung and her staff of the hospital photography department.

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