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Facial reanimations: part I—recent paralyses
YBJOM-4563; No. of Pages 6
ARTICLE IN PRESS Available online at www.sciencedirect.com
British Journal of Oral and Maxillofacial Surgery xxx (2015) xxx–xxx
Facial reanimations: part I—recent paralyses F. Biglioli ∗ Head of Maxillo-Facial Surgery Unit, San Paolo University Hospital, Milan, Italy Accepted 25 June 2015
Abstract Unilateral facial paralysis is a common condition: 1 in every 60 people will experience Bell’s palsy during the course of their life, and the residual deficits are particularly problematic for those who do not spontaneously recover the function of the facial nerve. Functionally the most relevant defect is lack of corneal lubrication because of inability to close the eyelid or blink. Morphologically, this presents as obvious ptosis caused by absence of the muscle tone at rest. “Restitutio ad integrum” of a paralysed face by operation is currently impossible, but realistic targets are improvement of facial symmetry and partial recovery of closure of the eyelids and smiling. Movements of the forehead and lower lip tend to be neglected targets for intervention because they are of less functional importance. Recent paralyses are those in which the mimetic musculature may be reactivated by provision of neural input, and the time limit is generally 18-24 months. Electromyography helps to detect it by assessing the presence of muscular fibrillations. If those are not detectable paralyses are considered to be long-standing, and new musculature must be transferred into the face, generally by transplantation of a muscular free flap or of the temporalis muscle in several different ways. When the facial nerve has been severed by trauma or during operation, immediate reconstruction must be considered and the simplest and most efficient is direct neurorrhaphy. If an appreciable part of the nerve is missing and the proximal and distal nerve stumps do not meet, an interpositional nerve graft must be placed to guarantee neural continuity. When reconstruction of the total extracranial branch of the facial nerve is required, the thoracodorsal nerve has proved to be highly effective. In case immediate reconstruction cannot be accomplished and the trunk of the facial nerve is not available as a donor nerve, mimetic musculature may be reactivated by provision of new neural input. Strong inputs from the masseteric or hypoglossus nerves may be mixed with those that arise from branches of the contralateral facial nerve after 2 cross-face nerve grafts have been placed, and good functional recovery is generally obtained. Several ancillary procedures are required to improve the end results in most cases. © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Keywords: Facial palsy; Facial reanimation; Facial nerve
Introduction Unilateral facial paralysis is a common condition. One in every 2500 people in the west develop Bell’s palsy in each year, and 1 in every 60 will have it during their lives.1 The outcomes of certain operations on the cranial base and brain may be compromised by the palsy, the aetiology of which may be congenital, developmental, traumatic, or otherwise. ∗ Correspondence to: Unità Operativa di Chirurgia Maxillo-Facciale, Ospedale San Paolo, Via A. di Rudinì 8, 20142 Milano, Italy. Tel.: +39 02 8184 4143; fax: +39 02 5032 3106. E-mail address: [email protected]
Facial paralysis greatly affects the quality of life, as it causes facial distortion and asymmetry and related functional deficits, principally lack of lubrication of the eye. Currently, there is no operation that affords a “restitutio ad integrum” of the paralysed face. Our efforts are directed to minimising the results. Facial reanimation means to restore life to the face, so our final goal is to restore movement to the paralysed face. Although static procedures may correct facial asymmetry at rest, such procedures alone are not enough. The many techniques that have been devised to reanimate the face may be separated into 2 groups according to the time between the development of the lesion of the facial nerve and its treatment.
http://dx.doi.org/10.1016/j.bjoms.2015.06.023 0266-4356/© 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Biglioli F. Facial reanimations: part I—recent paralyses. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.06.023
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Table 1 Timing of early repair of the facial nerve.
Table 2 Nerve sources.
Clinical condition
Timing of operation
Quantitative stimuli
Qualitative stimuli
Surgical discontinuation Trauma
Immediate Contemporaneous with the treatment of the skeletal trauma Eight months after onset if no appreciable clinical recovery is evident Six months after onset if no appreciable clinical recovery is evident Masseteric-facial nerve neurorrhaphy plus 2 cross-face nerve grafts
Hypoglossal nerve Masseteric nerve
Homolateral facial nerve Branches of the contralateral facial nerve
Bell’s palsy Second or third palsy Patient referred no later than 16 months after onset of paralysis Patient referred later than 16 months after onset of paralysis
Need for ancillary surgery
Masseteric-temporofacial branch of facial nerve neurorrhaphy 30% XII - jump graft - cervicofacial branch of facial nerve neurorrhaphy 2 cross-face nerve grafts Not before 6 months after first clinical signs of recovery from facial palsy
In other words, the treatments of recent and long-standing facial paralyses differ. After a period of time, which varies according to the type of muscle and the patient, a muscle becomes irreversibly fibrotic and it is useless to seek to provide new neural input. Electromyography (EMG) is of fundamental importance when intervention is planned.2 Patients with recent paralyses have fibrillations of the mimetic musculature, and if these fibrillations cannot be recorded, the paralysis must be considered long-standing. Recent paralyses are treated by replacing the neural input as soon as possible. Immediate facial nerve reconstruction When the facial nerve is severed by trauma or during an operation immediate reconstruction must be considered (Table 1), and the simplest and most efficient treatment is direct neurorrhaphy. If an appreciable part of the nerve is missing, and the proximal and distal nerve stumps do not meet, an interpositional nerve graft must be placed to guarantee neural continuity. When reconstruction of the total extracranial branch of the facial nerve is required, the thoracodorsal nerve has proved to be highly effective,3 as its anatomy closely resembles that of the facial nerve. Epineural neurorrhaphies are optimal to treat the facial nerve trunk or its tiny branches, and placement of a few 10/0 or 11/0 epineural stitches guarantees correct matching of the proximal and distal stumps. The use of fibrin glue over the neurorrhaphy at the end of the operation protects the repair against possible stretching by masticatory muscles. This step is not essential, however, because the use of fibrin glue may lead to excessive scarring and reduce the effectiveness of the neurorrhaphy. In some instances, particularly if the lesion is endocranial, a neurorrhaphy may be impossible because the lesion is too deep or a lesion of the facial nerve is located at the point of neural exit from the bulbopontine angle. The neural structure is not well-defined in that region, as the bundle of fibres looks
Deep temporalis nerve Spinal accessory nerve Phrenic nerve Glossopharyngeal/C4/C7 nerves
like “toothpaste”. In such instances it is best to choose a motor nerve as repair material to maximise the chance of functional recovery of the facial nerve. A new motor nerve may also be considered when a patient is referred several months after a surgical lesion and it is too difficult to coapt the proximal facial nerve, or efforts to find the nerve would be associated with excessive morbidity or a low probability of success, or both. Indeed, nerve damage may be extensive after some operations on the cranial base or endocranial procedures. A viable mimetic musculature is a prerequisite for reconstruction of the facial nerve. Mimetic muscles irreversibly atrophy over time, and such atrophy may be complete by 18 months, though not in all patients. Preoperative EMG is essential to rule out early irreversible atrophy, which seldom develops earlier than 12 months after the onset of palsy, particularly in cases of recurrent facial palsy, palsy caused by radiotherapy, and Ramsay-Hunt syndrome. A new motor source is required to reconstruct the facial nerve when a patient with Bell’s palsy has not recovered substantially 8 months after onset. Satisfactory recovery is impossible if mimetic movement is absent at that time. EMG must also be used to confirm that possible new motor sources (mainly the hypoglossus, masseteric, deep temporalis, and spinal accessory nerves) are functioning normally. A thorough medical history is required to rule out paralytic evolution of donor motor nerves. For example, a contralateral facial nerve should not be chosen if a second neurosurgical procedure might be required to treat a bilateral acoustic neuroma. The masseteric nerve should not be considered as a possible donor nerve if a residual brain tumour lies close to the trigeminal nucleus, and future surgery or radiotherapy might hamper masseteric viability. In such cases, an extracranial neurorrhaphy between the facial nerve trunk and an alternative motor source should be considered. Motor sources may be divided into 2 groups: those that impart strong stimuli and those that impart good-quality stimuli (Table 2). The first class includes motor nerves other than the facial; the hypoglossus and masseteric nerves are the most common.4–6 “Qualitative” motor stimuli When a person expresses emotions such as amusement, sadness, or surprise, the facial nerve (only) controls the
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facial expression by activating mimetic muscles. Other motor nerves that are connected to the facial nerve to afford new motor input must be trained to become activated to express an emotion.7 If activation of mimetic musculature depends on a motor source other than the facial nerve, and it is sought to smile voluntarily, patients must initially bite while smiling (if the masseteric nerve is to fire) or must move the tongue (if the hypoglossus nerve is to fire). Such efforts are tedious, and it is necessary to train the donor nerve. Specific physiotherapy is required; some patients become able to smile without the need for another simultaneous movement (so-called automatism). This is achieved by learning to smile in a certain way in the same manner as, with much practice, a tennis player serves without thinking of all the necessary movements. However, emotions are another matter. No nerve other than the facial nerve is activated when any of the multitude of emotions is conveyed. No smile or laugh will be spontaneous. Research workers who study spontaneous activation of the facial nerve when the “funny” emotion is experienced work principally with patients with Moebius sequence, who have so-called cortical adaptation.8 Such patients are rare.9 Reduction in corneal lubrication is the principal functional deficit in patients with facial paralysis and it may (rarely) progress to partial or total loss of visual acuity. Voluntary closure of the eyelid plays only a minor part in corneal lubrication as blinking (automatic closure of the eyelids) is the main factor that ensures the correct distribution of tear film, and occurs spontaneously 10-19 times/minute.10 Consequently, recovery of blinking should be the principal goal of facial reanimation. Again, no motor nerve other than the facial nerve will suffice. The logical consequence is that the best-quality neural stimulus is afforded by the facial nerve, because its activation reflects the natural wish to produce a particular mimetic movement at a specific moment. The nerve is also activated in response to emotion. When the homolateral facial nerve is unavailable for neurorrhaphy, one or more contralateral facial nerve branches may be coapted to ensure stimulation without development of a partial paralysis. The stimulus is transferred to the impaired facial nerve using so-called “cross-face” nerve grafts.11,12 The main drawback of such grafts is that they deliver only a small stimulus, which is seldom enough to produce a valid facial movement. The functionality of cross-face nerve grafts is improved by a distal anastomosis being made during a second procedure. However, the effect is often inadequate unless a stronger neural input is added to the cross-facing. A serious concern when severing a healthy branch of the facial nerve at a donor site is not to create a segmental paralysis. To avoid this it is essential to cut the branch immediately distal to the anterior margin of the parotid gland. In more distal regions, several neural anastomoses among the facial nerve branches ensure adequate maintenance of function. If more than one branch is used in cross-facing, it is prudent to leave an intact branch between each 2 donor branches to maintain a pathway of distally active neural anastomoses.
3
Although up to 4 cross-face nerve grafts have been placed at the same time,13 usually only 1 or 2 are used to avoid excessive weakening of the healthy hemiface. If a large branch is evident at the exit of the parotid gland, it is logical to trace that branch distally until it divides into 2 smaller branches, one of which can be coapted. Temporary weakness of the mimetic musculature that is innervated by the donor branch of the facial nerve is extremely rare, and generally resolves spontaneously within a few months.
“Quantitative” motor stimuli When it is considered that contralateral branches of the facial nerve afford the best-quality stimuli, it is often necessary to increase the quantity of neural input by coapting a second powerful motor source, and the first such source proposed (in 1879) was the XI nerve.14 This is indeed an effective motor source, but its stimulation of shoulder and neck movements is matched only with difficulty to facial expression on the healthy side. In fact, arm movements sometimes cause involuntary activation of mimetic muscles and create embarrassment for patients. Currently a spinal accessory nerve is used only if the masseteric or hypoglossus nerve is not available. Today the hypoglossus nerve is the most popular substitute motor source for reactivation of the facial nerve. It has been used to this end for many years, the procedure is easy, and it is possible to achieve high rates of functional reactivation of the facial nerve. The amplitudes of the mimetic movements produced are generally adequate, although for most patients it is difficult to couple tongue movement with smiling or closure of the eyelids. Specific physiotherapy is required to improve the results,15 the affected hemiface looks unmoved when emotions are evoked, and high rates of hemitongue paralysis can impair chewing, swallowing, and speech.16 To reduce morbidity, it was sought to coapt only part of hypoglossus fibres by side-to-end neurorrhaphy.17 The extent of reinnervation is lower than that of classical end-to-end neurorrhaphy, and this technical “advance” essentially reduces both efficacy and morbidity. The masseteric nerve was first used for facial reanimation by Spira in 1978,5 and was popularised by the Toronto group to treat developmental paralyses in patients with Moebius sequence.18 The nerve was also effective for treating a series of patients who did not have Moebius sequence.7 Currently the masseteric nerve is widely used to impart new neural input to a paralysed face. The nerve is a motor branch of the third root of the trigeminus, with a mean (SD) axonal count of 1542 (291).19 This is low, but sufficient to trigger mimetic movements with excursions comparable to those provided by the XII cranial nerve.20 The principal advantage of using the masseteric nerve is the negligible morbidity associated with harvesting it, which is in contrast to what happens when the hypoglossal nerve is to be used.
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Fig. 1. Patient affected by left facial paralysis lasting 12 months (published with the patient’s permission).
The masseteric nerve may also be used for segmental reanimation of the face, which allows quicker and more efficient reinnervation. The natural function of the masseteric nerve is control of biting. Although this is clearly remote from mimetic functioning of the musculature, biting is associated more easily with smiling than is contemporaneous movement of the tongue, which is required when the XII cranial nerve is used. Other possible donor motor nerves (including the temporalis, phrenic, glossopharyngeal, C4, and C7) are seldom used either because they are not easily accessible or because harvesting is associated with severe morbidity. Surgical correction of recent paralysis Terzis and Tzafetta were the first to admix quantitative and qualitative stimuli using the technique known as “babysitting”.13 Thirty percent of the hypoglossal fibres were connected to the trunk of the damaged facial nerve to maintain “healthy” mimetic muscles. When ingrowing axons arrived at the distal ends of 2 or more cross-face nerve grafts, they were connected to branches of the facial nerve on the paralysed side. Tomita et al. went one step further to develop simultaneous double innervation, the so-called neural supercharging.21 The hypoglossal nerve afforded a high degree of innervation, and the quality of the stimulus
Fig. 2. Diagram of planned facial reanimation: masseteric-facial nerve neurorrhaphy plus 2 cross-face nerve grafts (one to achieve spontaneity of smiling and one for restoration of blinking).
was ensured by the contralateral facial nerve. Variants of this technique were later developed by others.22 The optimum method of treating recent paralyses is to reinnervate the facial nerve trunk by masseteric-to-facial nerve neurorrhaphy, with the addition of 2 cross-face nerve grafts, one to the branch of the orbicularis oculi and one to the great zygomatic muscle. The masseteric nerve affords strong innervation of the mimetic musculature, whereas the crossface nerve grafts re-establish blinking and smiling Figs. 1–6, Supplementary videos 1 and 2). Some technical variations may be considered in specific cases. The quantitative motor stimulus may be delivered by the hypoglossal, the deep temporalis, or spinal nerves, if the masseteric nerve is not available, and the quantitative motor stimulus may be delivered by both the masseteric nerve and 30% of the fibres of the hypoglossus. The masseteric nerve is anastomosed directly to the temporofacial branch of the facial nerve, and part of the hypoglossus is anastomosed to the cervicofacial branch by a jump graft. This variant is particularly indicated for patients with “heavy” soft tissues, and those with high-level ptosis or paralysis of more than 16 months’ duration in whom mimetic muscle fibrillations are evident on EMG. Simultaneous soft tissue suspensions may be achieved by grafting of the fascia lata or transposition of the temporalis
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Fig. 3. Later ancillary surgery done to improve final result: a minitemporalis flap was transferred to the middle-third of the face to improve symmetry. Atrophy of upper and lower hemilips was treated by 2 lipofilling procedures (published with the patient’s permission).
muscle in patients with “heavy” soft tissues, high-level ptosis, or paralysis of more than 16 months’ duration.23,24 Most facial reanimations are improved by ancillary procedures.25 The possibilities are many, and address several different aspects of paralysis. Static refinements focus principally on improving the position of the eyelid and middle-face ptosis at rest. Dynamic procedures aim to increase symmetry during facial expression by the addition of further neural stimuli. Finally, injections of botulin toxin type A may render the face more symmetrical by reducing movement on
Fig. 5. Natural and well-balanced smile 24 months’ postoperatively (published with the patient’s permission).
Fig. 6. Eyelids closed 24 months’ postoperatively (published with the patient’s permission).
the healthy side. The morbidity associated with these procedures is low compared with that of further operations, but the costs and efforts are not negligible if a procedure needs to be repeated.
Conclusions
Fig. 4. Good symmetry of the face at rest 24 months’ postoperatively (published with the patient’s permission).
Immediate facial nerve neurorrhaphy yields the best reanimation results. If the trunk of the facial nerve is not available, masseteric-to-facial nerve neurorrhaphy with placement of 2 cross-face nerve grafts is the gold standard for treatment of recent paralysis. Variants of this technique, and ancillary
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procedures, may better address individual patient’s needs and improve outcomes.
Conflict of Interest We have no conflict of interest.
Ethics statement/confirmation of patients’ permission The patients have given consent to publication.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.bjoms. 2015.06.023.
References 1. McCaul JA, Cascarini L, Godden D, et al. Evidence based management of Bell’s palsy. Br J Oral Maxillofac Surg 2014;52:387–91. 2. Terzis JK, Olivares FS. Secondary surgery in adult facial paralysis reanimation. Plast Reconstr Surg 2009;124:1916–31. 3. Biglioli F, Colombo V, Pedrazzoli M, et al. Thoracodorsal nerve graft for reconstruction of facial nerve branching. J Craniomaxillofac Surg 2014;42:e8–14. 4. Korte W. Nerve grafting: facial nerve on hyperglossal nerve (in German). Dtsch Med Wochenschr 1903;17:293–5. 5. Spira M. Anastomosis of masseteric nerve to lower division of facial nerve for correction of lower facial paralysis. Preliminary report. Plast Reconstr Surg 1978;61:330–4. 6. Biglioli F, Frigerio A, Colombo V, et al. Masseteric-facial nerve anastomosis for early facial reanimation. J Craniomaxillofac Surg 2012;40:149–55. 7. Biglioli F, Colombo V, Tarabbia F, et al. Recovery of emotional smiling function in free-flap facial reanimation. J Oral Maxillofac Surg 2012;70:2413–8. 8. Manktelow RT, Tomat LR, Zuker RM, et al. Smile reconstruction in adults with free muscle transfer innervated by the masseter motor nerve: effectiveness and cerebral adaptation. Plast Reconstr Surg 2006;118:885–99.
9. Gousheh J, Arasteh E. Treatment of facial paralysis: dynamic reanimation of spontaneous facial expression-apropos of 655 patients. Plast Reconstr Surg 2011;128:693e–703e. 10. Sforza C, Rango M, Galante D, et al. Spontaneous blinking in healthy persons: an optoelectronic study of eyelid motion. Ophthalmic Physiol Opt 2008;28:345–53. 11. Scaramella LF. Anastomosis between the 2 facial nerves (in Italian). Arch Ital Otol 1971;82:209–16. 12. Smith JW. A new technique of facial animation. In: Hueston JH, editor. Transactions of the Fifth International Congress of Plastic Surgery. NSW: Butterworths; 1971. p. 83. 13. Terzis JK, Tzafetta K. The “babysitter” procedure: minihypoglossal to facial nerve transfer and cross-facial nerve grafting. Plast Reconstr Surg 2009;123:865–76. 14. Drobnik, cited by Sawicki B, in Chepault: The Status of Neurosurgery. Paris: J Rueff, 1902:189 (as quoted by Google Scholar). 15. Dalla Toffola E, Pavese C, Cecini M, et al. Hypoglossal-facial nerve anastomosis and rehabilitation in patients with complete facial palsy: cohort study of 30 patients followed up for three years. Funct Neurol 2014;29:183–7. 16. Yetiser S, Karapinar U. Hypoglossal-facial nerve anastomosis: a meta-analytic study. Ann Otol Rhinol Laryngol 2007;116:542–9. 17. Arai H, Sato K, Yanai A. Hemihypoglossal-facial nerve anastomosis in treating unilateral facial palsy after acoustic neurinoma resection. J Neurosurg 1995;82:51–4. 18. Zuker RM1, Goldberg CS, Manktelow RT. Facial animation in children with Möbius syndrome after segmental gracilis muscle transplant. Plast Reconstr Surg 2000;106:1–9. 19. Coombs CJ, Ek EW, Wu T, et al. Masseteric-facial nerve coaptation--an alternative technique for facial nerve reinnervation. J Plast Reconstr Aesthet Surg 2009;62:1580–8. 20. Sforza C, Tarabbia F, Mapelli A, et al. Facial reanimation with masseteric to facial nerve transfer: a three-dimensional longitudinal quantitative evaluation. J Plast Reconstr Aesthet Surg 2014;67:1378–86. 21. Tomita K, Hosokawa K, Yano K. Reanimation of reversible facial paralysis by the double innervation technique using an intraneural-dissected sural nerve graft. J Plast Reconstr Aesthet Surg 2010;63:e535–9. 22. Bianchi B, Ferri A, Ferrari S, et al. Cross-facial nerve graft and masseteric nerve cooptation for one-stage facial reanimation: principles, indications, and surgical procedure. Head Neck 2014;36:235–40. 23. McLaughlin CR. Surgical support in permanent facial paralysis. Plast Reconstr Surg (1946) 1953;11:302–14. 24. Labbé D. Lengthening of temporal myoplasty and reanimation of lips. Technical note (in French). Ann Chir Plast Esthét 1997;42: 44–8. 25. Takushima A, Harii K, Asato H, et al. Revisional operations improve results of neurovascular free muscle transfer for treatment of facial paralysis. Plast Reconstr Surg 2005;116:371–80.
Please cite this article in press as: Biglioli F. Facial reanimations: part I—recent paralyses. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.06.023
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British Journal of Oral and Maxillofacial Surgery xxx (2015) xxx–xxx
Facial reanimations: part I—recent paralyses F. Biglioli ∗ Head of Maxillo-Facial Surgery Unit, San Paolo University Hospital, Milan, Italy Accepted 25 June 2015
Abstract Unilateral facial paralysis is a common condition: 1 in every 60 people will experience Bell’s palsy during the course of their life, and the residual deficits are particularly problematic for those who do not spontaneously recover the function of the facial nerve. Functionally the most relevant defect is lack of corneal lubrication because of inability to close the eyelid or blink. Morphologically, this presents as obvious ptosis caused by absence of the muscle tone at rest. “Restitutio ad integrum” of a paralysed face by operation is currently impossible, but realistic targets are improvement of facial symmetry and partial recovery of closure of the eyelids and smiling. Movements of the forehead and lower lip tend to be neglected targets for intervention because they are of less functional importance. Recent paralyses are those in which the mimetic musculature may be reactivated by provision of neural input, and the time limit is generally 18-24 months. Electromyography helps to detect it by assessing the presence of muscular fibrillations. If those are not detectable paralyses are considered to be long-standing, and new musculature must be transferred into the face, generally by transplantation of a muscular free flap or of the temporalis muscle in several different ways. When the facial nerve has been severed by trauma or during operation, immediate reconstruction must be considered and the simplest and most efficient is direct neurorrhaphy. If an appreciable part of the nerve is missing and the proximal and distal nerve stumps do not meet, an interpositional nerve graft must be placed to guarantee neural continuity. When reconstruction of the total extracranial branch of the facial nerve is required, the thoracodorsal nerve has proved to be highly effective. In case immediate reconstruction cannot be accomplished and the trunk of the facial nerve is not available as a donor nerve, mimetic musculature may be reactivated by provision of new neural input. Strong inputs from the masseteric or hypoglossus nerves may be mixed with those that arise from branches of the contralateral facial nerve after 2 cross-face nerve grafts have been placed, and good functional recovery is generally obtained. Several ancillary procedures are required to improve the end results in most cases. © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Keywords: Facial palsy; Facial reanimation; Facial nerve
Introduction Unilateral facial paralysis is a common condition. One in every 2500 people in the west develop Bell’s palsy in each year, and 1 in every 60 will have it during their lives.1 The outcomes of certain operations on the cranial base and brain may be compromised by the palsy, the aetiology of which may be congenital, developmental, traumatic, or otherwise. ∗ Correspondence to: Unità Operativa di Chirurgia Maxillo-Facciale, Ospedale San Paolo, Via A. di Rudinì 8, 20142 Milano, Italy. Tel.: +39 02 8184 4143; fax: +39 02 5032 3106. E-mail address: [email protected]
Facial paralysis greatly affects the quality of life, as it causes facial distortion and asymmetry and related functional deficits, principally lack of lubrication of the eye. Currently, there is no operation that affords a “restitutio ad integrum” of the paralysed face. Our efforts are directed to minimising the results. Facial reanimation means to restore life to the face, so our final goal is to restore movement to the paralysed face. Although static procedures may correct facial asymmetry at rest, such procedures alone are not enough. The many techniques that have been devised to reanimate the face may be separated into 2 groups according to the time between the development of the lesion of the facial nerve and its treatment.
http://dx.doi.org/10.1016/j.bjoms.2015.06.023 0266-4356/© 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Biglioli F. Facial reanimations: part I—recent paralyses. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.06.023
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Table 1 Timing of early repair of the facial nerve.
Table 2 Nerve sources.
Clinical condition
Timing of operation
Quantitative stimuli
Qualitative stimuli
Surgical discontinuation Trauma
Immediate Contemporaneous with the treatment of the skeletal trauma Eight months after onset if no appreciable clinical recovery is evident Six months after onset if no appreciable clinical recovery is evident Masseteric-facial nerve neurorrhaphy plus 2 cross-face nerve grafts
Hypoglossal nerve Masseteric nerve
Homolateral facial nerve Branches of the contralateral facial nerve
Bell’s palsy Second or third palsy Patient referred no later than 16 months after onset of paralysis Patient referred later than 16 months after onset of paralysis
Need for ancillary surgery
Masseteric-temporofacial branch of facial nerve neurorrhaphy 30% XII - jump graft - cervicofacial branch of facial nerve neurorrhaphy 2 cross-face nerve grafts Not before 6 months after first clinical signs of recovery from facial palsy
In other words, the treatments of recent and long-standing facial paralyses differ. After a period of time, which varies according to the type of muscle and the patient, a muscle becomes irreversibly fibrotic and it is useless to seek to provide new neural input. Electromyography (EMG) is of fundamental importance when intervention is planned.2 Patients with recent paralyses have fibrillations of the mimetic musculature, and if these fibrillations cannot be recorded, the paralysis must be considered long-standing. Recent paralyses are treated by replacing the neural input as soon as possible. Immediate facial nerve reconstruction When the facial nerve is severed by trauma or during an operation immediate reconstruction must be considered (Table 1), and the simplest and most efficient treatment is direct neurorrhaphy. If an appreciable part of the nerve is missing, and the proximal and distal nerve stumps do not meet, an interpositional nerve graft must be placed to guarantee neural continuity. When reconstruction of the total extracranial branch of the facial nerve is required, the thoracodorsal nerve has proved to be highly effective,3 as its anatomy closely resembles that of the facial nerve. Epineural neurorrhaphies are optimal to treat the facial nerve trunk or its tiny branches, and placement of a few 10/0 or 11/0 epineural stitches guarantees correct matching of the proximal and distal stumps. The use of fibrin glue over the neurorrhaphy at the end of the operation protects the repair against possible stretching by masticatory muscles. This step is not essential, however, because the use of fibrin glue may lead to excessive scarring and reduce the effectiveness of the neurorrhaphy. In some instances, particularly if the lesion is endocranial, a neurorrhaphy may be impossible because the lesion is too deep or a lesion of the facial nerve is located at the point of neural exit from the bulbopontine angle. The neural structure is not well-defined in that region, as the bundle of fibres looks
Deep temporalis nerve Spinal accessory nerve Phrenic nerve Glossopharyngeal/C4/C7 nerves
like “toothpaste”. In such instances it is best to choose a motor nerve as repair material to maximise the chance of functional recovery of the facial nerve. A new motor nerve may also be considered when a patient is referred several months after a surgical lesion and it is too difficult to coapt the proximal facial nerve, or efforts to find the nerve would be associated with excessive morbidity or a low probability of success, or both. Indeed, nerve damage may be extensive after some operations on the cranial base or endocranial procedures. A viable mimetic musculature is a prerequisite for reconstruction of the facial nerve. Mimetic muscles irreversibly atrophy over time, and such atrophy may be complete by 18 months, though not in all patients. Preoperative EMG is essential to rule out early irreversible atrophy, which seldom develops earlier than 12 months after the onset of palsy, particularly in cases of recurrent facial palsy, palsy caused by radiotherapy, and Ramsay-Hunt syndrome. A new motor source is required to reconstruct the facial nerve when a patient with Bell’s palsy has not recovered substantially 8 months after onset. Satisfactory recovery is impossible if mimetic movement is absent at that time. EMG must also be used to confirm that possible new motor sources (mainly the hypoglossus, masseteric, deep temporalis, and spinal accessory nerves) are functioning normally. A thorough medical history is required to rule out paralytic evolution of donor motor nerves. For example, a contralateral facial nerve should not be chosen if a second neurosurgical procedure might be required to treat a bilateral acoustic neuroma. The masseteric nerve should not be considered as a possible donor nerve if a residual brain tumour lies close to the trigeminal nucleus, and future surgery or radiotherapy might hamper masseteric viability. In such cases, an extracranial neurorrhaphy between the facial nerve trunk and an alternative motor source should be considered. Motor sources may be divided into 2 groups: those that impart strong stimuli and those that impart good-quality stimuli (Table 2). The first class includes motor nerves other than the facial; the hypoglossus and masseteric nerves are the most common.4–6 “Qualitative” motor stimuli When a person expresses emotions such as amusement, sadness, or surprise, the facial nerve (only) controls the
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facial expression by activating mimetic muscles. Other motor nerves that are connected to the facial nerve to afford new motor input must be trained to become activated to express an emotion.7 If activation of mimetic musculature depends on a motor source other than the facial nerve, and it is sought to smile voluntarily, patients must initially bite while smiling (if the masseteric nerve is to fire) or must move the tongue (if the hypoglossus nerve is to fire). Such efforts are tedious, and it is necessary to train the donor nerve. Specific physiotherapy is required; some patients become able to smile without the need for another simultaneous movement (so-called automatism). This is achieved by learning to smile in a certain way in the same manner as, with much practice, a tennis player serves without thinking of all the necessary movements. However, emotions are another matter. No nerve other than the facial nerve is activated when any of the multitude of emotions is conveyed. No smile or laugh will be spontaneous. Research workers who study spontaneous activation of the facial nerve when the “funny” emotion is experienced work principally with patients with Moebius sequence, who have so-called cortical adaptation.8 Such patients are rare.9 Reduction in corneal lubrication is the principal functional deficit in patients with facial paralysis and it may (rarely) progress to partial or total loss of visual acuity. Voluntary closure of the eyelid plays only a minor part in corneal lubrication as blinking (automatic closure of the eyelids) is the main factor that ensures the correct distribution of tear film, and occurs spontaneously 10-19 times/minute.10 Consequently, recovery of blinking should be the principal goal of facial reanimation. Again, no motor nerve other than the facial nerve will suffice. The logical consequence is that the best-quality neural stimulus is afforded by the facial nerve, because its activation reflects the natural wish to produce a particular mimetic movement at a specific moment. The nerve is also activated in response to emotion. When the homolateral facial nerve is unavailable for neurorrhaphy, one or more contralateral facial nerve branches may be coapted to ensure stimulation without development of a partial paralysis. The stimulus is transferred to the impaired facial nerve using so-called “cross-face” nerve grafts.11,12 The main drawback of such grafts is that they deliver only a small stimulus, which is seldom enough to produce a valid facial movement. The functionality of cross-face nerve grafts is improved by a distal anastomosis being made during a second procedure. However, the effect is often inadequate unless a stronger neural input is added to the cross-facing. A serious concern when severing a healthy branch of the facial nerve at a donor site is not to create a segmental paralysis. To avoid this it is essential to cut the branch immediately distal to the anterior margin of the parotid gland. In more distal regions, several neural anastomoses among the facial nerve branches ensure adequate maintenance of function. If more than one branch is used in cross-facing, it is prudent to leave an intact branch between each 2 donor branches to maintain a pathway of distally active neural anastomoses.
3
Although up to 4 cross-face nerve grafts have been placed at the same time,13 usually only 1 or 2 are used to avoid excessive weakening of the healthy hemiface. If a large branch is evident at the exit of the parotid gland, it is logical to trace that branch distally until it divides into 2 smaller branches, one of which can be coapted. Temporary weakness of the mimetic musculature that is innervated by the donor branch of the facial nerve is extremely rare, and generally resolves spontaneously within a few months.
“Quantitative” motor stimuli When it is considered that contralateral branches of the facial nerve afford the best-quality stimuli, it is often necessary to increase the quantity of neural input by coapting a second powerful motor source, and the first such source proposed (in 1879) was the XI nerve.14 This is indeed an effective motor source, but its stimulation of shoulder and neck movements is matched only with difficulty to facial expression on the healthy side. In fact, arm movements sometimes cause involuntary activation of mimetic muscles and create embarrassment for patients. Currently a spinal accessory nerve is used only if the masseteric or hypoglossus nerve is not available. Today the hypoglossus nerve is the most popular substitute motor source for reactivation of the facial nerve. It has been used to this end for many years, the procedure is easy, and it is possible to achieve high rates of functional reactivation of the facial nerve. The amplitudes of the mimetic movements produced are generally adequate, although for most patients it is difficult to couple tongue movement with smiling or closure of the eyelids. Specific physiotherapy is required to improve the results,15 the affected hemiface looks unmoved when emotions are evoked, and high rates of hemitongue paralysis can impair chewing, swallowing, and speech.16 To reduce morbidity, it was sought to coapt only part of hypoglossus fibres by side-to-end neurorrhaphy.17 The extent of reinnervation is lower than that of classical end-to-end neurorrhaphy, and this technical “advance” essentially reduces both efficacy and morbidity. The masseteric nerve was first used for facial reanimation by Spira in 1978,5 and was popularised by the Toronto group to treat developmental paralyses in patients with Moebius sequence.18 The nerve was also effective for treating a series of patients who did not have Moebius sequence.7 Currently the masseteric nerve is widely used to impart new neural input to a paralysed face. The nerve is a motor branch of the third root of the trigeminus, with a mean (SD) axonal count of 1542 (291).19 This is low, but sufficient to trigger mimetic movements with excursions comparable to those provided by the XII cranial nerve.20 The principal advantage of using the masseteric nerve is the negligible morbidity associated with harvesting it, which is in contrast to what happens when the hypoglossal nerve is to be used.
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Fig. 1. Patient affected by left facial paralysis lasting 12 months (published with the patient’s permission).
The masseteric nerve may also be used for segmental reanimation of the face, which allows quicker and more efficient reinnervation. The natural function of the masseteric nerve is control of biting. Although this is clearly remote from mimetic functioning of the musculature, biting is associated more easily with smiling than is contemporaneous movement of the tongue, which is required when the XII cranial nerve is used. Other possible donor motor nerves (including the temporalis, phrenic, glossopharyngeal, C4, and C7) are seldom used either because they are not easily accessible or because harvesting is associated with severe morbidity. Surgical correction of recent paralysis Terzis and Tzafetta were the first to admix quantitative and qualitative stimuli using the technique known as “babysitting”.13 Thirty percent of the hypoglossal fibres were connected to the trunk of the damaged facial nerve to maintain “healthy” mimetic muscles. When ingrowing axons arrived at the distal ends of 2 or more cross-face nerve grafts, they were connected to branches of the facial nerve on the paralysed side. Tomita et al. went one step further to develop simultaneous double innervation, the so-called neural supercharging.21 The hypoglossal nerve afforded a high degree of innervation, and the quality of the stimulus
Fig. 2. Diagram of planned facial reanimation: masseteric-facial nerve neurorrhaphy plus 2 cross-face nerve grafts (one to achieve spontaneity of smiling and one for restoration of blinking).
was ensured by the contralateral facial nerve. Variants of this technique were later developed by others.22 The optimum method of treating recent paralyses is to reinnervate the facial nerve trunk by masseteric-to-facial nerve neurorrhaphy, with the addition of 2 cross-face nerve grafts, one to the branch of the orbicularis oculi and one to the great zygomatic muscle. The masseteric nerve affords strong innervation of the mimetic musculature, whereas the crossface nerve grafts re-establish blinking and smiling Figs. 1–6, Supplementary videos 1 and 2). Some technical variations may be considered in specific cases. The quantitative motor stimulus may be delivered by the hypoglossal, the deep temporalis, or spinal nerves, if the masseteric nerve is not available, and the quantitative motor stimulus may be delivered by both the masseteric nerve and 30% of the fibres of the hypoglossus. The masseteric nerve is anastomosed directly to the temporofacial branch of the facial nerve, and part of the hypoglossus is anastomosed to the cervicofacial branch by a jump graft. This variant is particularly indicated for patients with “heavy” soft tissues, and those with high-level ptosis or paralysis of more than 16 months’ duration in whom mimetic muscle fibrillations are evident on EMG. Simultaneous soft tissue suspensions may be achieved by grafting of the fascia lata or transposition of the temporalis
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Fig. 3. Later ancillary surgery done to improve final result: a minitemporalis flap was transferred to the middle-third of the face to improve symmetry. Atrophy of upper and lower hemilips was treated by 2 lipofilling procedures (published with the patient’s permission).
muscle in patients with “heavy” soft tissues, high-level ptosis, or paralysis of more than 16 months’ duration.23,24 Most facial reanimations are improved by ancillary procedures.25 The possibilities are many, and address several different aspects of paralysis. Static refinements focus principally on improving the position of the eyelid and middle-face ptosis at rest. Dynamic procedures aim to increase symmetry during facial expression by the addition of further neural stimuli. Finally, injections of botulin toxin type A may render the face more symmetrical by reducing movement on
Fig. 5. Natural and well-balanced smile 24 months’ postoperatively (published with the patient’s permission).
Fig. 6. Eyelids closed 24 months’ postoperatively (published with the patient’s permission).
the healthy side. The morbidity associated with these procedures is low compared with that of further operations, but the costs and efforts are not negligible if a procedure needs to be repeated.
Conclusions
Fig. 4. Good symmetry of the face at rest 24 months’ postoperatively (published with the patient’s permission).
Immediate facial nerve neurorrhaphy yields the best reanimation results. If the trunk of the facial nerve is not available, masseteric-to-facial nerve neurorrhaphy with placement of 2 cross-face nerve grafts is the gold standard for treatment of recent paralysis. Variants of this technique, and ancillary
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procedures, may better address individual patient’s needs and improve outcomes.
Conflict of Interest We have no conflict of interest.
Ethics statement/confirmation of patients’ permission The patients have given consent to publication.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.bjoms. 2015.06.023.
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Please cite this article in press as: Biglioli F. Facial reanimations: part I—recent paralyses. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.06.023