REVIEW URRENT C OPINION
Masseteric nerve use in facial reanimation Douglas K. Henstrom
Purpose of review To review the growing literature on the use of the masseteric nerve in facial reanimation, from direct neurotization, to ‘baby-sitter’ techniques, to its use in powering neuromuscular free tissue transfer. We focus on the indications for the different uses based on the timing of the facial paralysis and other patient factors. Recent findings The use of the masseteric nerve in facial reanimation is gaining widespread acceptance for use in an expanding number of clinical scenarios. Surgeon’s experience and preference as well as patient selection are very important factors in choosing the appropriate surgical use of this nerve. Summary Facial reanimation surgery is a difficult challenge for any reconstructive surgeon. The use of the masseteric nerve branch to reanimate the face is gaining popularity. Its versatility, anatomical location, relative ease of dissection, low morbidity, and high potential for motor neural input make it an excellent option for many different reanimating techniques. The appropriate nerve use should be based on the type of facial paralysis, its timing, and patient factors such as age, prognosis, and desires. Understanding the benefits and potential drawbacks of utilizing this nerve represents an essential piece of knowledge for the facial reanimation surgeon. Keywords facial nerve, facial reanimation, gracilis muscle, masseteric nerve, neuromuscular transplant
INTRODUCTION Facial paralysis affects thousands of people every year. Although most of them recover to normal or near-normal functional levels, many will have longterm facial difficulties. In addition to the obvious distortion of facial morphology at rest and with movement, some of the functional consequences include difficulties with eye lubrication and protection, increased resistance of nasal inspiration, speech impairments, oral incompetence, and the ability to communicate nonverbally [1–3]. Causes of facial paralysis are varied, and current therapies are becoming just as varied. A review of the international English language literature shows a wide and growing range of surgical options that allows some degree of reanimation in facial paralysis. Options historically have included direct nerve repair, grafting with a donor nerve, coaptation utilizing a different motor nerve (hypoglossal, masseteric, spinal accessory, cervical rootlets, and phrenic), temporalis or masseter muscle flaps, and most recently the use of neuromuscular free tissue transfer. Often, treatment decisions are based on the surgeon’s preference and experience, as well as www.co-otolaryngology.com
patient factors such as age, overall health, diagnosis and prognosis, cause and timing of the facial paralysis, as well as status of both ipsilateral (affected) facial nerve and targeted muscles, as well as contralateral (unaffected) facial nerve [4]. Research into a better understanding of how to utilize the masseteric branch of V3 for facial reanimation surgery is growing both in the laboratory and clinically.
ANATOMY The motor nerve to the masseter is from the anterior division of the mandibular branch of the trigeminal nerve and is the largest of the three motor branches
Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA Correspondence to Douglas K. Henstrom, MD, FACS, Director, Department of Otolaryngology-Head and Neck Surgery, Facial Plastic Surgery and Facial Nerve Center, University of Iowa, 200 Hawkins Boulevard, Iowa City, IA 52242, USA. Tel: +1 319 356 3600; fax: +1 319 356 0555; e-mail: [email protected] Curr Opin Otolaryngol Head Neck Surg 2014, 22:284–290 DOI:10.1097/MOO.0000000000000070 Volume 22 Number 4 August 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Masseteric nerve use in facial reanimation Henstrom
KEY POINTS The masseteric nerve can be consistently found in the ‘subzygomatic’ triangle. Advantages of utilizing the masseteric nerve are location near native facial nerve branches, relative ease of dissection, possible length, high number of motor axons, fast reinnervation times, and low morbidity to chewing function. Disadvantages of using the masseteric nerve include the potential lack of true spontaneity in function and possible unwanted excess movement when masticating. The masseteric nerve can be successfully used in reanimating the face by direct neurotization with or without interposition grafts, ‘baby-sitter’ procedures, double innervation of native musculature or transplanted tissue, and in neuromuscular free tissue transfer. The use of the masseteric nerve to power a gracilis muscle neuromuscular transplant represents one of the most reliable and widely used techniques for reanimation of the paralyzed face.
of the trigeminal nerve [5]. After exiting the cranium via the foramen ovale, the nerve passes over the lateral pterygoid muscle and through the coronoid notch, a few millimeters anterior to the condyle of the mandible and posterior to the temporalis insertion onto the coronoid process [6], to enter the posterior surface of the masseter muscle near its origin. Of clinical importance is that the masseteric nerve is of sufficient length to allow tension-free direct coaptation with the facial nerve, when adequately dissected [5,7]. Coombs et al. [8] showed in a series of seven specimens an average number of myelinated axons contained in the distal masseteric nerves was 1543 292, which greatly outnumbers the cross-sectional counts of the facial nerve buccal branch, the distal end of a cross-face nerve graft, as well as the obturator nerve to the gracilis. Borschel’s histomorphometric analysis demonstrated the motor nerve to the masseter containing an average of 2775 470 myelinated fibers [9], again showing the significant potential neural input the masseteric nerve can provide. Brenner and Schoeller [7] also showed that in 35 of 36 specimens, multiple branches innervated the masseter at the level of the muscle entrance. This suggests that transection of a branch of the nerve may not cause severe loss of masseteric function. Others have since supported that clinically [8]. Recent anatomic studies have attempted to show the consistency of nerve position, direction
after exiting the infratemporal fossa, nerve size (diameter and length), and branching pattern to assist the surgeon in locating the nerve easily and without putting at risk other local structures [6,9,10 ]. On the basis of 10 cadaveric dissections and 11 consecutive patients, Collar et al. [10 ] described the ease of locating the motor branch to the masseter within the ‘subzygomatic triangle’. This triangle is formed by the inferior border of the zygomatic arch superiorly, a vertical line through the anterior border of the temporomandibular joint posteriorly, and the frontal branch of the facial nerve inferiorly and anteriorly. Within this triangle, they demonstrate the nerve following a line beginning at the angle formed by the temporomandibular joint and zygomatic arch, and crossing the midpoint of the triangle base formed by the frontal branch of the facial nerve. They located it consistently 10–15 mm deep to the parotidomasseteric fascia and showed clinically that this can be done in a quick, safe, and relatively noninvasive manner (Fig. 1). &
&
APPLICATIONS OF THE MASSETERIC NERVE There are three basic ways in which the masseteric nerve is being increasingly used; we will discuss the following uses: direct motor neurotization, babysitter and double innervation techniques, and the innervation of neuromuscular transplants.
FIGURE 1. Location and relevant anatomy of the masseteric nerve within the ‘subzygomatic triangle’. A, masseteric nerve; B, frontal branch of facial nerve; C, zygoma; D, coronoid process of mandible. Data from [10 ].
1068-9508 ß 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
&
www.co-otolaryngology.com
285
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Facial plastic surgery
Direct motor neurotization When the proximal stump of a damaged facial nerve cannot be used for coaptation, stimulation must be found through another nerve with motor input. Originally described by Korte [11] in 1903, the hypoglossal nerve has been the most widely utilized source for that motor input. The major disadvantages in using this nerve are the morbidity of losing input to the hemitongue and the resultant atrophy, which may impair speech and swallowing. In addition, the required tongue movement to enact the facial movements can be difficult for patients and lead to mass facial synkinetic type of movement. These consequences make it a contraindication in patients with other lower cranial nerve deficits. Because of these disadvantages, modifications to the original procedure strive to preserve some function of the hypoglossal nerve and thus tongue function. These modifications include transposition of only a section of the hypoglossal nerve, the use of jump grafts coapted at differing points along the hypoglossal nerve, and end-to-side neurorrhaphy with and without a window opened into the epineurium [12–18]. In 1978, Spira [19] first described the usefulness of the motor nerve to the masseter as a viable alternative to the hypoglossal nerve in facial reanimation. Indications for the use of the masseteric nerve include when the contralateral facial nerve is not available, Moebius syndrome, multiple lower cranial neuropathies, and when the onset of facial paralysis has been long enough ago to consider cross-face grafting (18–24 months after palsy) [8,20,21 ]. In 2004, Bermudez and Nieto [22] published a case report of masseteric–facial nerve transfer, in which they coapted the masseteric nerve to the main trunk of the injured facial nerve. Initial movement appeared 4 months postoperatively with complete recovery at 6 months. This alternative has recently been advocated and supported by other authors [8,23 ,24]. A great auricular nerve jump graft between the masseteric nerve and facial nerve branch was advocated by Biglioli, and resulted in excellent symmetry at rest and dynamic restoration of smile in two patients, good results in three cases, and adequate in two cases. None of their patients demonstrated a spontaneous smile and one patient demonstrated masseter muscle atrophy without chewing difficulty. One critical factor in selecting their patients was the presence of mimetic muscle fibrillations at preoperative electromyography. Fibrillations on electromyography recordings represent muscle fibers that are damaged, but not completely denervated and thus have the potential for reinnervation [23 ]. Using three-dimensional motion analysis, this same group showed a reduction &&
&
&
286
www.co-otolaryngology.com
(a)
(b)
(c)
(d)
FIGURE 2. Direct masseteric nerve to facial nerve coaptation. (a) Isolation of appropriate facial nerve branches. (b) Dissection under facial nerve branches into the masseter muscle (arrows depict line marking inferior border of zygoma). (c) Masseteric and zygomatic nerves transected and prepared for coaptation. (d) Direct masseteric nerve coaptation to facial nerve branch. M, masseteric nerve; , zygomatic branches of facial nerve.
in the significant presurgical asymmetry of facial movements [24]. Direct coaptation without nerve graft is now more commonly undertaken by most groups (Fig. 2). Coombs et al. [8] suggested direct neurotization of the buccal and zygomatic branches with the masseteric nerve. They conclude that this should restore facial tone, improve facial symmetry in repose, regain a voluntary and potentially spontaneous smile, and improve lower eyelid position and tone. Likewise, Bianchi et al. [25] reviewed all patients who underwent any usage of the masseteric nerve for reanimation of facial paralysis. Of their 60 patients, most of them underwent cross-facial grafting in conjunction with masseteric nerve coaptation, or the masseter nerve was used for innervating a neuromuscular transplant; however, four underwent direct masseteric–facial coaptation as the sole means of reanimating the face. In this group, facial contraction was restored after a mean of 4 months, with three patients having some degree of synkinesis. Three of their patients had moderate results and one had a good result utilizing the classification system described by Terzis and Noah [26]. A recent review by Hontanilla and Marre [20] compared utilizing the hemi-hypoglossal nerve (with sural nerve interpositional nerve graft) vs. the masseteric nerve for direct coaptation to the facial nerve. Utilizing their Facial Clima system they compared posttreatment commissural displacement and commissural contraction velocity of the treated Volume 22 Number 4 August 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Masseteric nerve use in facial reanimation Henstrom
side. They found that the mean percentage of recovery of both commissural displacement and contraction velocity did not differ between the two groups. However, patients undergoing masseteric–facial nerve coaptation showed a significantly faster onset of movement compared with those in the other group (62 4.6 days vs. 136 7.4 days). They concluded that reanimation can be effectively treated utilizing both methods, but that the use of the masseteric nerve allowed for quicker functional return and avoidance of donor nerve graft morbidity. Thus, they recommend using the masseteric nerve when both techniques are feasible. As a follow-up to that study, the same group published their results with a total of 23 patients undergoing masseteric–facial nerve coaptation [27 ], and state that it has become their preferred way of reanimation of the smile for patients with viable facial musculature. The disadvantage of using the masseteric nerve for direct coaptation to the facial nerve is that you lose the option of later using it to help power a free muscle transfer for reanimation. This nerve is commonly the backup nerve used to ‘salvage’ a failed cross-face nerve powered muscle transfer, and not having this nerve available will affect surgical options and planning. &&
true ‘baby-sitter’, especially compared to the previous use and reporting of the hypoglossal nerve. When its use has been reported in conjunction with cross-facial grafting, it usually has not been removed at a later date. Faria et al. [33] has even advocated not sectioning the masseteric nerve ‘baby-sitter’ in association with the cross-face grafting portion of the procedure, in order to increase muscle contraction. This double innervation technique was also reported by Bianchi et al. [25] in their review, revealing nine patients undergoing reinnervation with masseteric branch coaptation of ‘the inferior branch of the facial nerve in association with a cross-facial nerve-grafting technique’. Mean reinnervation time was 3 months in these patients. In a separate publication [21 ], they describe their technique of utilizing the masseteric nerve to innervate the lower division of the facial nerve and combine that with two cross-face grafts to innervate the middle and upper thirds of the face. In this way, they hypothesize a greater strength and quicker return of function of lower third facial contractions (mean of 3 months), but the spontaneity and involuntary actions in the other areas of the face (mean of 10.5 months). Although low in numbers, their results are promising when considering the double innervation techniques in patients with viable facial musculature. &&
‘Baby-sitter’ and double innervation procedures
Innervation for neuromuscular transplant
In traditional cross-facial nerve grafting procedures, there is an extended time period of deinnervated, unstimulated muscle. With this inactivity, the paralyzed muscle and neuromuscular junctions can develop irreversible atrophy and fibrosis, decreasing the success of the grafting once axonal regeneration does reach its destination. To help maintain muscle tone, this can be managed using a ‘baby-sitter’ procedure utilizing an alternative temporary coaptation with other motor nerves into the distal facial nerve branches or trunk in the same setting as cross-face nerve grafting. In a subsequent procedure, the regenerated cross-face nerve graft is transposed into the destined facial nerve branch(es) and the ‘babysitter’ is removed. Introduced by Terzis [28] in 1984, and subsequently modified and reported [29–33], this procedure first and most commonly uses the hypoglossal nerve as the ‘baby-sitter’. The consistent high rates of success utilizing the masseteric nerve with gracilis muscle transplant for facial reanimation [34–37] has inspired others to consider this donor nerve as a possible ‘baby-sitter’ in conjunction with a cross-face nerve graft procedure. However, to date, there has not been a significant reporting of the masseteric nerve as a
Utilizing the masseteric nerve to power a free tissue transfer for smile reanimation is its most widely utilized application. In 2000, Zuker et al. [35] first described their experience using the masseteric nerve as the donor source for bilateral free gracilis muscle transfer in 10 patients affected by Moebius syndrome. They found it to be very encouraging and subsequently expanded its use in more patients. They followed up that initial report with a series of 45 gracilis muscle transfers innervated by the masseteric motor nerve in 27 patients (age 16–61) with either unilateral or bilateral facial palsy showing excellent functional, emotional, and aesthetic results [38]. Since those first large reports, many centers around the world have used and reported their experiences using the masseteric nerve to power free tissue transfer for smile reanimation [34,36,39– 41,42 ]. This is most commonly done in a one-stage procedure to power the gracilis muscle (other commonly reported donor muscles include latissimus dorsi and pectoralis minor [43,44]). Interestingly, the largest published series of smile reanimation utilizing the gracilis muscle did not include any patient with the muscle powered by the masseteric nerve [45].
1068-9508 ß 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
&
www.co-otolaryngology.com
287
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Facial plastic surgery
The benefits of utilizing the masseteric nerve to power free muscle transfer in smile reanimation are the same reasons one might consider it in direct facial coaptation: relative ease of dissection in the surgical field, potential neural input, need for only one stage of surgery (as compared to the two-stage cross-facial innervation), relatively quick, clinically observable results (2–4 months), and low morbidity to mastication [35,36,41,42 ]. It is the preferred nerve of choice in certain clinical scenarios such as Moebius patients and NF2 patients [35,46]. It also consistently results in a wider range of commissure excursion after gracilis muscle transplantation compared with cross-face grafting [34,37,38] (Fig. 3). However, the main disadvantage of this donor nerve is the lack of spontaneity and synchronization of contraction while smiling. This can be very difficult to achieve and requires long postoperative rehabilitation, which must be planned for [4,34]. In Manktelow et al.’s [38] study of Moebius patients using masseter donor source, they reported the recovery of spontaneous smile in 89% of patients, at a mean follow-up of 4.7 years. They hypothesize that ‘cortical plasticity’ accounts for the development of a spontaneous smile in these patients. They also conclude with the caveat that the ability to smile spontaneously in these patients depends on the intensity of early practice. Some have shown that women may be able to produce a spontaneous smile at a higher rate than men following this surgery [47]. Other evidence supports the theory of cortical adaptation to restoration of smiling after free muscle transfer innervated by the masseteric nerve [48,49]. &
(a)
(b)
Faria et al. [37] suggested that an automatic smilinglike movement might be possible as smiling and chewing are similar functions, even if they have not observed any spontaneity in smiling within the group with the masseter nerve as donor source. He concluded that one-stage gracilis reanimation utilizing the masseteric nerve ‘produced more predictable and consistent results’, which is the basis for their recommendation. Whereas some degree of a spontaneous, emotionally driven smile may be possible in certain patient populations (i.e. Moebius patients), it is not seen or reported in all other series. Anecdotal cases have been described and theorized [48,49], but insufficient clinical evidence exists to show emotion-related muscle contractions. Another potential downside of using the masseteric nerve for innervation of the transferred muscle is the potential for involuntary, unwanted excess movement during normal mastication. If we look hard enough, we are likely to find some excess movement in all patients who successfully undergo this procedure; however, in my experience, and the reported experience of others [50], it is not clinically significant and most, if not all, patients would still have the surgery. As with direct neurotization, using a cross-face nerve graft does not preclude the use of the masseteric nerve at the same time. The double innervation of a transplanted muscle might be the ultimate choice to give enough nerve input to get the desired contraction out of the muscle and still develop true emotional spontaneity of the movement [51].
CONCLUSION The masseteric nerve is growing in popularity as the motor source for reanimating the paralyzed face. The major advantages of using this nerve for facial reanimation are the close proximity of the nerve to the facial nerve branches – possibly negating the need for a jump graft which leads to relatively fast reinnervation times (usually less than 3 months), the strength of the motor impulse, and the lack of morbidity to the masticatory muscle function [8,23 ,24,52]. Currently, there are not enough data about its usefulness as a true ‘baby-sitter’, but its use in direct neurotization of the facial nerve in conjunction with cross-face grafts or double innervation of a transplanted muscle may prove to be a true combination of the best of both worlds. Despite the potential advantages, and the ability to utilize the masseteric nerve in many different cases of facial paralysis, careful patient and technique selection is necessary for satisfactory results. If used unsuccessfully with direct coaptation to the &
FIGURE 3. (a) Preoperative smile photograph of a patient with neurofibromatosis type 2 and left-sided facial paralysis. (b) Postoperative smile of a patient 1 year after undergoing gracilis muscle transfer powered by the masseteric nerve. 288
www.co-otolaryngology.com
Volume 22 Number 4 August 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Masseteric nerve use in facial reanimation Henstrom
facial nerve, it will not be available for possible salvage surgery utilizing a neuromuscular transplant. Acknowledgements None. Conflicts of interest There are no conflicts of interest.
REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest && of outstanding interest 1. Mehta RP, Hadlock TA. Botulinum toxin and quality of life in patients with facial paralysis. Arch Facial Plast Surg 2008; 10:84–87. 2. Wachtman GS, Cohn JF, VanSwearingen JM, Manders EK. Automated tracking of facial features in patients with facial neuromuscular dysfunction. Plast Reconstr Surg 2001; 107:1124–1133. 3. Popat H, Henley E, Richmond S, et al. A comparison of the reproducibility of verbal and nonverbal facial gestures using three-dimensional motion analysis. Otolaryngol Head Neck Surg 2010; 142:867–872. 4. Bianchi B, Ferri A, Sesenna E. Facial reanimation after nerve sacrifice in the treatment of head and neck cancer. Curr Opin Otolaryngol Head Neck Surg 2012; 20:114–119. 5. Fournier HD, Denis F, Papon X, et al. An anatomical study of the motor distribution of the mandibular nerve for a masseteric–facial anastomosis to restore facial function. Surg Radiol Anat 1997; 19:241–244. 6. Cotrufo S, Hart A, Payne AP, et al. Topographic anatomy of the nerve to masseter: an anatomical and clinical study. J Plast Reconstr Anesth Surg 2011; 64:1424–1429. 7. Brenner E, Schoeller T. Masseteric nerve: a possible donor for facial nerve anastomosis? Clin Anat 1998; 11:396–400. 8. 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; 62:1580–1588. 9. Borschel GH, Kawamura DH, Kasukurthi R, et al. The motor nerve to the masseter muscle: an anatomic and histomorphometric study to facilitate its use in facial reanimation. J Plast Reconstr Anesth Surg 2012; 65:363– 366. 10. Collar RM, Byrne PJ, Boahene KD. The subzygomatic triangle: rapid, minimally & invasive identification of the masseteric nerve for facial reanimation. Plast Reconstr Surg 2013; 132:183–188. A great description of an easy, anatomically based way to quickly and efficiently identify the masseteric nerve. 11. Korte W. Nerve grafting: facial nerve on hypoglossal. Dtsch Med Wochenschr 1903; 17:293–295. [in German] 12. Atlas MD, Lowinger DS. A new technique for hypoglossal–facial nerve repair. Laryngoscope 1997; 107:984–991. 13. Conley J, Baker DC. Hypoglossal–facial nerve anastomosis for reinnervation of the paralyzed face. Plast Reconstr Surg 1979; 63:63–72. 14. Koh KS, Kim J, Kim CJ, et al. Hypoglossal–facial crossover in facial-nerve palsy: pure end-to-side anastomosis technique. Br J Plast Surg 2002; 55:25– 31. 15. May M, Sobol SM, Mester SJ. Hypoglossal–facial nerve interpositional-jump graft for facial reanimation without tongue atrophy. Otolaryngol Head Neck Surg 1991; 104:818–825. 16. Noah EM, Williams A, Jorgenson C, et al. End-to-side neurorrhaphy: a histologic and morphometric study of axonal sprouting into an end-to-side nerve graft. J Reconstr Microsurg 1997; 13:99–106. 17. Pensak ML, Jackson CG, Glasscock ME 3rd, Gulya AJ. Facial reanimation with the VII–XII anastomosis: analysis of the functional and psychologic results. Otolaryngol Head Neck Surg 1986; 94:305–310. 18. Viterbo F, Trindade JC, Hoshino K, Mazzoni Neto A. Latero-terminal neurorrhaphy without removal of the epineural sheath. Experimental study in rats. Rev Paul Med 1992; 110:267–275. 19. Spira M. Anastomosis of masseteric nerve to lower division of facial nerve for correction of lower facial paralysis. Preliminary report. Plast Reconstr Surg 1978; 61:330–334. 20. Hontanilla B, Marre D. Comparison of hemihypoglossal nerve versus masseteric nerve transpositions in the rehabilitation of short-term facial paralysis using the Facial Clima evaluating system. Plast Reconstr Surg 2012; 130:662e–672e.
21. 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; 36:235–240. An excellent review of the techniques and use of the masseteric–facial nerve direct coaptation in the setting of additional cross-face nerve grafting for maximizing the functional and cosmetic outcomes. 22. Bermudez LE, Nieto LE. Masseteric–facial nerve anastomosis: case report. J Reconstr Microsurg 2004; 20:25–30. 23. Biglioli F, Frigerio A, Colombo V, et al. Masseteric–facial nerve anastomosis & for early facial reanimation. J Craniomaxillofac Surg 2012; 40:149–155. This study entails good reasoning, description of their procedure and outcomes with long enough follow-up to draw conclusions regarding direct masseteric– facial nerve transfers. 24. Sforza C, Frigerio A, Mapelli A, et al. Facial movement before and after masseteric–facial nerves anastomosis: a three-dimensional optoelectronic pilot study. J Craniomaxillofac Surg 2012; 40:473–479. 25. Bianchi B, Ferri A, Ferrari S, et al. The masseteric nerve: a versatile power source in facial animation techniques. Br J Oral Maxillofac Surg 2014; 52:264–269. 26. Terzis JK, Noah ME. Analysis of 100 cases of free-muscle transplantation for facial paralysis. Plast Reconstr Surg 1997; 99:1905–1921. 27. Hontanilla B, Marre D, Cabello A. Masseteric nerve for reanimation of the && smile in short-term facial paralysis. Br J Oral Maxillofac Surg 2014; 52:118– 123. The largest single review of patients undergoing direct masseteric –facial nerve transfers and excellent quantitative data reviewing not only total movement, but also the speed of that movement and how it compares to the unaffected side. 28. Terzis JK. Babysitters. An exciting new concept in facial reanimation. In: Castro D, editor. 6th International Symposium on the facial nerve. Rio de Janeiro, Brazil: Kugler & Ghedini; 1988. 29. Kalantarian B, Rice DC, Tiangco DA, Terzis JK. Gains and losses of the XII–VII component of the ‘baby-sitter’ procedure: a morphometric analysis. J Reconstr Microsurg 1998; 14:459–471. 30. Mersa B, Tiangco DA, Terzis JK. Efficacy of the ‘baby-sitter’ procedure after prolonged denervation. J Reconstr Microsurg 2000; 16:27–35. 31. Terzis JK, Tzafetta K. The ‘babysitter’ procedure: minihypoglossal to facial nerve transfer and cross-facial nerve grafting. Plast Reconstr Surg 2009; 123:865–876. 32. Terzis JK, Tzafetta K. ‘Babysitter’ procedure with concomitant muscle transfer in facial paralysis. Plast Reconstr Surg 2009; 124:1142–1156. 33. Faria JC, Scopel GP, Ferreira MC. Facial reanimation with masseteric nerve: babysitter or permanent procedure? Preliminary results. Ann Plast Surg 2010; 64:31–34. 34. Bae YC, Zuker RM, Manktelow RT, Wade S. A comparison of commissure excursion following gracilis muscle transplantation for facial paralysis using a cross-face nerve graft versus the motor nerve to the masseter nerve. Plast Reconstr Surg 2006; 117:2407–2413. 35. Zuker RM, Goldberg CS, Manktelow RT. Facial animation in children with Mobius syndrome after segmental gracilis muscle transplant. Plast Reconstr Surg 2000; 106:1–8; discussion 9. 36. Hadlock TA, Malo JS, Cheney ML, Henstrom DK. Free gracilis transfer for smile in children: the Massachusetts Eye and Ear Infirmary Experience in excursion and quality-of-life changes. Arch Facial Plast Surg 2011; 13:190– 194. 37. Faria JC, Scopel GP, Busnardo FF, Ferreira MC. Nerve sources for facial reanimation with muscle transplant in patients with unilateral facial palsy: clinical analysis of 3 techniques. Ann Plast Surg 2007; 59:87–91. 38. Manktelow RT, Tomat LR, Zuker RM, Chang M. Smile reconstruction in adults with free muscle transfer innervated by the masseter motor nerve: effectiveness and cerebral adaptation. Plast Reconstr Surg 2006; 118:885–899. 39. Bianchi B, Copelli C, Ferrari S, et al. Facial animation with free-muscle transfer innervated by the masseter motor nerve in unilateral facial paralysis. J Oral Maxillofac Surg 2010; 68:1524–1529. 40. Bianchi B, Copelli C, Ferrari S, et al. Use of the masseter motor nerve in facial animation with free muscle transfer. Br J Oral Maxillofac Surg 2012; 50:650– 653. 41. Eisenhardt SU, Thiele JR, Stark GB, Bannasch H. Comparison of cross face nerve graft with masseteric nerve as donor nerves for free functional muscle transfers in facial reanimation surgery. Handchir Mikrochir Plast Chir 2013; 45:223–228. 42. Hontanilla B, Marre D, Cabello A. Facial reanimation with gracilis muscle & transfer neurotized to cross-facial nerve graft versus masseteric nerve: a comparative study using the FACIAL CLIMA evaluating system. Plast Reconstr Surg 2013; 131:1241–1252. An excellent large review comparing the outcomes of gracilis muscle transfer between those powered by a cross-face graft and the masseteric nerve. Quantitative measurements include total excursion distance and speed of movement compared to unaffected side. 43. Dellon AL, Mackinnon SE. Segmentally innervated latissimus dorsi muscle. Microsurgical transfer for facial reanimation. J Reconstr Microsurg 1985; 2:7–12. 44. Terzis JK. Pectoralis minor: a unique muscle for correction of facial palsy. Plast Reconstr Surg 1989; 83:767–776. &&
1068-9508 ß 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
www.co-otolaryngology.com
289
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Facial plastic surgery 45. 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. 46. Vakharia KT, Henstrom D, Plotkin SR, et al. Facial reanimation of patients with neurofibromatosis type 2. Neurosurgery 2012; 70:237–243. 47. Hontanilla B, Marre D. Differences between sexes in dissociation and spontaneity of smile in facial paralysis reanimation with the masseteric nerve. Head Neck 2013. [Epub ahead of print] 48. Lifchez SD, Matloub HS, Gosain AK. Cortical adaptation to restoration of smiling after free muscle transfer innervated by the nerve to the masseter. Plast Reconstr Surg 2005; 115:1472–1479; discussion 1480–1482.
290
www.co-otolaryngology.com
49. Marre D, Hontanilla B. Brain plasticity in Mobius syndrome after unilateral muscle transfer: case report and review of the literature. Ann Plast Surg 2012; 68:97–100. 50. Rozen S, Harrison B. Involuntary movement during mastication in patients with long-term facial paralysis reanimated with a partial gracilis free neuromuscular flap innervated by the masseteric nerve. Plast Reconstr Surg 2013; 132: 110e–116e. 51. Biglioli F, Colombo V, Tarabbia F, et al. Double innervation in free-flap surgery for long-standing facial paralysis. J Plast Reconstr Aesthet Surg 2012; 65:1343–1349. 52. Klebuc MJ. Facial reanimation using the masseter-to-facial nerve transfer. Plast Reconstr Surg 2011; 127:1909–1915.
Volume 22 Number 4 August 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Masseteric nerve use in facial reanimation Douglas K. Henstrom
Purpose of review To review the growing literature on the use of the masseteric nerve in facial reanimation, from direct neurotization, to ‘baby-sitter’ techniques, to its use in powering neuromuscular free tissue transfer. We focus on the indications for the different uses based on the timing of the facial paralysis and other patient factors. Recent findings The use of the masseteric nerve in facial reanimation is gaining widespread acceptance for use in an expanding number of clinical scenarios. Surgeon’s experience and preference as well as patient selection are very important factors in choosing the appropriate surgical use of this nerve. Summary Facial reanimation surgery is a difficult challenge for any reconstructive surgeon. The use of the masseteric nerve branch to reanimate the face is gaining popularity. Its versatility, anatomical location, relative ease of dissection, low morbidity, and high potential for motor neural input make it an excellent option for many different reanimating techniques. The appropriate nerve use should be based on the type of facial paralysis, its timing, and patient factors such as age, prognosis, and desires. Understanding the benefits and potential drawbacks of utilizing this nerve represents an essential piece of knowledge for the facial reanimation surgeon. Keywords facial nerve, facial reanimation, gracilis muscle, masseteric nerve, neuromuscular transplant
INTRODUCTION Facial paralysis affects thousands of people every year. Although most of them recover to normal or near-normal functional levels, many will have longterm facial difficulties. In addition to the obvious distortion of facial morphology at rest and with movement, some of the functional consequences include difficulties with eye lubrication and protection, increased resistance of nasal inspiration, speech impairments, oral incompetence, and the ability to communicate nonverbally [1–3]. Causes of facial paralysis are varied, and current therapies are becoming just as varied. A review of the international English language literature shows a wide and growing range of surgical options that allows some degree of reanimation in facial paralysis. Options historically have included direct nerve repair, grafting with a donor nerve, coaptation utilizing a different motor nerve (hypoglossal, masseteric, spinal accessory, cervical rootlets, and phrenic), temporalis or masseter muscle flaps, and most recently the use of neuromuscular free tissue transfer. Often, treatment decisions are based on the surgeon’s preference and experience, as well as www.co-otolaryngology.com
patient factors such as age, overall health, diagnosis and prognosis, cause and timing of the facial paralysis, as well as status of both ipsilateral (affected) facial nerve and targeted muscles, as well as contralateral (unaffected) facial nerve [4]. Research into a better understanding of how to utilize the masseteric branch of V3 for facial reanimation surgery is growing both in the laboratory and clinically.
ANATOMY The motor nerve to the masseter is from the anterior division of the mandibular branch of the trigeminal nerve and is the largest of the three motor branches
Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA Correspondence to Douglas K. Henstrom, MD, FACS, Director, Department of Otolaryngology-Head and Neck Surgery, Facial Plastic Surgery and Facial Nerve Center, University of Iowa, 200 Hawkins Boulevard, Iowa City, IA 52242, USA. Tel: +1 319 356 3600; fax: +1 319 356 0555; e-mail: [email protected] Curr Opin Otolaryngol Head Neck Surg 2014, 22:284–290 DOI:10.1097/MOO.0000000000000070 Volume 22 Number 4 August 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Masseteric nerve use in facial reanimation Henstrom
KEY POINTS The masseteric nerve can be consistently found in the ‘subzygomatic’ triangle. Advantages of utilizing the masseteric nerve are location near native facial nerve branches, relative ease of dissection, possible length, high number of motor axons, fast reinnervation times, and low morbidity to chewing function. Disadvantages of using the masseteric nerve include the potential lack of true spontaneity in function and possible unwanted excess movement when masticating. The masseteric nerve can be successfully used in reanimating the face by direct neurotization with or without interposition grafts, ‘baby-sitter’ procedures, double innervation of native musculature or transplanted tissue, and in neuromuscular free tissue transfer. The use of the masseteric nerve to power a gracilis muscle neuromuscular transplant represents one of the most reliable and widely used techniques for reanimation of the paralyzed face.
of the trigeminal nerve [5]. After exiting the cranium via the foramen ovale, the nerve passes over the lateral pterygoid muscle and through the coronoid notch, a few millimeters anterior to the condyle of the mandible and posterior to the temporalis insertion onto the coronoid process [6], to enter the posterior surface of the masseter muscle near its origin. Of clinical importance is that the masseteric nerve is of sufficient length to allow tension-free direct coaptation with the facial nerve, when adequately dissected [5,7]. Coombs et al. [8] showed in a series of seven specimens an average number of myelinated axons contained in the distal masseteric nerves was 1543 292, which greatly outnumbers the cross-sectional counts of the facial nerve buccal branch, the distal end of a cross-face nerve graft, as well as the obturator nerve to the gracilis. Borschel’s histomorphometric analysis demonstrated the motor nerve to the masseter containing an average of 2775 470 myelinated fibers [9], again showing the significant potential neural input the masseteric nerve can provide. Brenner and Schoeller [7] also showed that in 35 of 36 specimens, multiple branches innervated the masseter at the level of the muscle entrance. This suggests that transection of a branch of the nerve may not cause severe loss of masseteric function. Others have since supported that clinically [8]. Recent anatomic studies have attempted to show the consistency of nerve position, direction
after exiting the infratemporal fossa, nerve size (diameter and length), and branching pattern to assist the surgeon in locating the nerve easily and without putting at risk other local structures [6,9,10 ]. On the basis of 10 cadaveric dissections and 11 consecutive patients, Collar et al. [10 ] described the ease of locating the motor branch to the masseter within the ‘subzygomatic triangle’. This triangle is formed by the inferior border of the zygomatic arch superiorly, a vertical line through the anterior border of the temporomandibular joint posteriorly, and the frontal branch of the facial nerve inferiorly and anteriorly. Within this triangle, they demonstrate the nerve following a line beginning at the angle formed by the temporomandibular joint and zygomatic arch, and crossing the midpoint of the triangle base formed by the frontal branch of the facial nerve. They located it consistently 10–15 mm deep to the parotidomasseteric fascia and showed clinically that this can be done in a quick, safe, and relatively noninvasive manner (Fig. 1). &
&
APPLICATIONS OF THE MASSETERIC NERVE There are three basic ways in which the masseteric nerve is being increasingly used; we will discuss the following uses: direct motor neurotization, babysitter and double innervation techniques, and the innervation of neuromuscular transplants.
FIGURE 1. Location and relevant anatomy of the masseteric nerve within the ‘subzygomatic triangle’. A, masseteric nerve; B, frontal branch of facial nerve; C, zygoma; D, coronoid process of mandible. Data from [10 ].
1068-9508 ß 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
&
www.co-otolaryngology.com
285
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Facial plastic surgery
Direct motor neurotization When the proximal stump of a damaged facial nerve cannot be used for coaptation, stimulation must be found through another nerve with motor input. Originally described by Korte [11] in 1903, the hypoglossal nerve has been the most widely utilized source for that motor input. The major disadvantages in using this nerve are the morbidity of losing input to the hemitongue and the resultant atrophy, which may impair speech and swallowing. In addition, the required tongue movement to enact the facial movements can be difficult for patients and lead to mass facial synkinetic type of movement. These consequences make it a contraindication in patients with other lower cranial nerve deficits. Because of these disadvantages, modifications to the original procedure strive to preserve some function of the hypoglossal nerve and thus tongue function. These modifications include transposition of only a section of the hypoglossal nerve, the use of jump grafts coapted at differing points along the hypoglossal nerve, and end-to-side neurorrhaphy with and without a window opened into the epineurium [12–18]. In 1978, Spira [19] first described the usefulness of the motor nerve to the masseter as a viable alternative to the hypoglossal nerve in facial reanimation. Indications for the use of the masseteric nerve include when the contralateral facial nerve is not available, Moebius syndrome, multiple lower cranial neuropathies, and when the onset of facial paralysis has been long enough ago to consider cross-face grafting (18–24 months after palsy) [8,20,21 ]. In 2004, Bermudez and Nieto [22] published a case report of masseteric–facial nerve transfer, in which they coapted the masseteric nerve to the main trunk of the injured facial nerve. Initial movement appeared 4 months postoperatively with complete recovery at 6 months. This alternative has recently been advocated and supported by other authors [8,23 ,24]. A great auricular nerve jump graft between the masseteric nerve and facial nerve branch was advocated by Biglioli, and resulted in excellent symmetry at rest and dynamic restoration of smile in two patients, good results in three cases, and adequate in two cases. None of their patients demonstrated a spontaneous smile and one patient demonstrated masseter muscle atrophy without chewing difficulty. One critical factor in selecting their patients was the presence of mimetic muscle fibrillations at preoperative electromyography. Fibrillations on electromyography recordings represent muscle fibers that are damaged, but not completely denervated and thus have the potential for reinnervation [23 ]. Using three-dimensional motion analysis, this same group showed a reduction &&
&
&
286
www.co-otolaryngology.com
(a)
(b)
(c)
(d)
FIGURE 2. Direct masseteric nerve to facial nerve coaptation. (a) Isolation of appropriate facial nerve branches. (b) Dissection under facial nerve branches into the masseter muscle (arrows depict line marking inferior border of zygoma). (c) Masseteric and zygomatic nerves transected and prepared for coaptation. (d) Direct masseteric nerve coaptation to facial nerve branch. M, masseteric nerve; , zygomatic branches of facial nerve.
in the significant presurgical asymmetry of facial movements [24]. Direct coaptation without nerve graft is now more commonly undertaken by most groups (Fig. 2). Coombs et al. [8] suggested direct neurotization of the buccal and zygomatic branches with the masseteric nerve. They conclude that this should restore facial tone, improve facial symmetry in repose, regain a voluntary and potentially spontaneous smile, and improve lower eyelid position and tone. Likewise, Bianchi et al. [25] reviewed all patients who underwent any usage of the masseteric nerve for reanimation of facial paralysis. Of their 60 patients, most of them underwent cross-facial grafting in conjunction with masseteric nerve coaptation, or the masseter nerve was used for innervating a neuromuscular transplant; however, four underwent direct masseteric–facial coaptation as the sole means of reanimating the face. In this group, facial contraction was restored after a mean of 4 months, with three patients having some degree of synkinesis. Three of their patients had moderate results and one had a good result utilizing the classification system described by Terzis and Noah [26]. A recent review by Hontanilla and Marre [20] compared utilizing the hemi-hypoglossal nerve (with sural nerve interpositional nerve graft) vs. the masseteric nerve for direct coaptation to the facial nerve. Utilizing their Facial Clima system they compared posttreatment commissural displacement and commissural contraction velocity of the treated Volume 22 Number 4 August 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Masseteric nerve use in facial reanimation Henstrom
side. They found that the mean percentage of recovery of both commissural displacement and contraction velocity did not differ between the two groups. However, patients undergoing masseteric–facial nerve coaptation showed a significantly faster onset of movement compared with those in the other group (62 4.6 days vs. 136 7.4 days). They concluded that reanimation can be effectively treated utilizing both methods, but that the use of the masseteric nerve allowed for quicker functional return and avoidance of donor nerve graft morbidity. Thus, they recommend using the masseteric nerve when both techniques are feasible. As a follow-up to that study, the same group published their results with a total of 23 patients undergoing masseteric–facial nerve coaptation [27 ], and state that it has become their preferred way of reanimation of the smile for patients with viable facial musculature. The disadvantage of using the masseteric nerve for direct coaptation to the facial nerve is that you lose the option of later using it to help power a free muscle transfer for reanimation. This nerve is commonly the backup nerve used to ‘salvage’ a failed cross-face nerve powered muscle transfer, and not having this nerve available will affect surgical options and planning. &&
true ‘baby-sitter’, especially compared to the previous use and reporting of the hypoglossal nerve. When its use has been reported in conjunction with cross-facial grafting, it usually has not been removed at a later date. Faria et al. [33] has even advocated not sectioning the masseteric nerve ‘baby-sitter’ in association with the cross-face grafting portion of the procedure, in order to increase muscle contraction. This double innervation technique was also reported by Bianchi et al. [25] in their review, revealing nine patients undergoing reinnervation with masseteric branch coaptation of ‘the inferior branch of the facial nerve in association with a cross-facial nerve-grafting technique’. Mean reinnervation time was 3 months in these patients. In a separate publication [21 ], they describe their technique of utilizing the masseteric nerve to innervate the lower division of the facial nerve and combine that with two cross-face grafts to innervate the middle and upper thirds of the face. In this way, they hypothesize a greater strength and quicker return of function of lower third facial contractions (mean of 3 months), but the spontaneity and involuntary actions in the other areas of the face (mean of 10.5 months). Although low in numbers, their results are promising when considering the double innervation techniques in patients with viable facial musculature. &&
‘Baby-sitter’ and double innervation procedures
Innervation for neuromuscular transplant
In traditional cross-facial nerve grafting procedures, there is an extended time period of deinnervated, unstimulated muscle. With this inactivity, the paralyzed muscle and neuromuscular junctions can develop irreversible atrophy and fibrosis, decreasing the success of the grafting once axonal regeneration does reach its destination. To help maintain muscle tone, this can be managed using a ‘baby-sitter’ procedure utilizing an alternative temporary coaptation with other motor nerves into the distal facial nerve branches or trunk in the same setting as cross-face nerve grafting. In a subsequent procedure, the regenerated cross-face nerve graft is transposed into the destined facial nerve branch(es) and the ‘babysitter’ is removed. Introduced by Terzis [28] in 1984, and subsequently modified and reported [29–33], this procedure first and most commonly uses the hypoglossal nerve as the ‘baby-sitter’. The consistent high rates of success utilizing the masseteric nerve with gracilis muscle transplant for facial reanimation [34–37] has inspired others to consider this donor nerve as a possible ‘baby-sitter’ in conjunction with a cross-face nerve graft procedure. However, to date, there has not been a significant reporting of the masseteric nerve as a
Utilizing the masseteric nerve to power a free tissue transfer for smile reanimation is its most widely utilized application. In 2000, Zuker et al. [35] first described their experience using the masseteric nerve as the donor source for bilateral free gracilis muscle transfer in 10 patients affected by Moebius syndrome. They found it to be very encouraging and subsequently expanded its use in more patients. They followed up that initial report with a series of 45 gracilis muscle transfers innervated by the masseteric motor nerve in 27 patients (age 16–61) with either unilateral or bilateral facial palsy showing excellent functional, emotional, and aesthetic results [38]. Since those first large reports, many centers around the world have used and reported their experiences using the masseteric nerve to power free tissue transfer for smile reanimation [34,36,39– 41,42 ]. This is most commonly done in a one-stage procedure to power the gracilis muscle (other commonly reported donor muscles include latissimus dorsi and pectoralis minor [43,44]). Interestingly, the largest published series of smile reanimation utilizing the gracilis muscle did not include any patient with the muscle powered by the masseteric nerve [45].
1068-9508 ß 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
&
www.co-otolaryngology.com
287
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Facial plastic surgery
The benefits of utilizing the masseteric nerve to power free muscle transfer in smile reanimation are the same reasons one might consider it in direct facial coaptation: relative ease of dissection in the surgical field, potential neural input, need for only one stage of surgery (as compared to the two-stage cross-facial innervation), relatively quick, clinically observable results (2–4 months), and low morbidity to mastication [35,36,41,42 ]. It is the preferred nerve of choice in certain clinical scenarios such as Moebius patients and NF2 patients [35,46]. It also consistently results in a wider range of commissure excursion after gracilis muscle transplantation compared with cross-face grafting [34,37,38] (Fig. 3). However, the main disadvantage of this donor nerve is the lack of spontaneity and synchronization of contraction while smiling. This can be very difficult to achieve and requires long postoperative rehabilitation, which must be planned for [4,34]. In Manktelow et al.’s [38] study of Moebius patients using masseter donor source, they reported the recovery of spontaneous smile in 89% of patients, at a mean follow-up of 4.7 years. They hypothesize that ‘cortical plasticity’ accounts for the development of a spontaneous smile in these patients. They also conclude with the caveat that the ability to smile spontaneously in these patients depends on the intensity of early practice. Some have shown that women may be able to produce a spontaneous smile at a higher rate than men following this surgery [47]. Other evidence supports the theory of cortical adaptation to restoration of smiling after free muscle transfer innervated by the masseteric nerve [48,49]. &
(a)
(b)
Faria et al. [37] suggested that an automatic smilinglike movement might be possible as smiling and chewing are similar functions, even if they have not observed any spontaneity in smiling within the group with the masseter nerve as donor source. He concluded that one-stage gracilis reanimation utilizing the masseteric nerve ‘produced more predictable and consistent results’, which is the basis for their recommendation. Whereas some degree of a spontaneous, emotionally driven smile may be possible in certain patient populations (i.e. Moebius patients), it is not seen or reported in all other series. Anecdotal cases have been described and theorized [48,49], but insufficient clinical evidence exists to show emotion-related muscle contractions. Another potential downside of using the masseteric nerve for innervation of the transferred muscle is the potential for involuntary, unwanted excess movement during normal mastication. If we look hard enough, we are likely to find some excess movement in all patients who successfully undergo this procedure; however, in my experience, and the reported experience of others [50], it is not clinically significant and most, if not all, patients would still have the surgery. As with direct neurotization, using a cross-face nerve graft does not preclude the use of the masseteric nerve at the same time. The double innervation of a transplanted muscle might be the ultimate choice to give enough nerve input to get the desired contraction out of the muscle and still develop true emotional spontaneity of the movement [51].
CONCLUSION The masseteric nerve is growing in popularity as the motor source for reanimating the paralyzed face. The major advantages of using this nerve for facial reanimation are the close proximity of the nerve to the facial nerve branches – possibly negating the need for a jump graft which leads to relatively fast reinnervation times (usually less than 3 months), the strength of the motor impulse, and the lack of morbidity to the masticatory muscle function [8,23 ,24,52]. Currently, there are not enough data about its usefulness as a true ‘baby-sitter’, but its use in direct neurotization of the facial nerve in conjunction with cross-face grafts or double innervation of a transplanted muscle may prove to be a true combination of the best of both worlds. Despite the potential advantages, and the ability to utilize the masseteric nerve in many different cases of facial paralysis, careful patient and technique selection is necessary for satisfactory results. If used unsuccessfully with direct coaptation to the &
FIGURE 3. (a) Preoperative smile photograph of a patient with neurofibromatosis type 2 and left-sided facial paralysis. (b) Postoperative smile of a patient 1 year after undergoing gracilis muscle transfer powered by the masseteric nerve. 288
www.co-otolaryngology.com
Volume 22 Number 4 August 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Masseteric nerve use in facial reanimation Henstrom
facial nerve, it will not be available for possible salvage surgery utilizing a neuromuscular transplant. Acknowledgements None. Conflicts of interest There are no conflicts of interest.
REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest && of outstanding interest 1. Mehta RP, Hadlock TA. Botulinum toxin and quality of life in patients with facial paralysis. Arch Facial Plast Surg 2008; 10:84–87. 2. Wachtman GS, Cohn JF, VanSwearingen JM, Manders EK. Automated tracking of facial features in patients with facial neuromuscular dysfunction. Plast Reconstr Surg 2001; 107:1124–1133. 3. Popat H, Henley E, Richmond S, et al. A comparison of the reproducibility of verbal and nonverbal facial gestures using three-dimensional motion analysis. Otolaryngol Head Neck Surg 2010; 142:867–872. 4. Bianchi B, Ferri A, Sesenna E. Facial reanimation after nerve sacrifice in the treatment of head and neck cancer. Curr Opin Otolaryngol Head Neck Surg 2012; 20:114–119. 5. Fournier HD, Denis F, Papon X, et al. An anatomical study of the motor distribution of the mandibular nerve for a masseteric–facial anastomosis to restore facial function. Surg Radiol Anat 1997; 19:241–244. 6. Cotrufo S, Hart A, Payne AP, et al. Topographic anatomy of the nerve to masseter: an anatomical and clinical study. J Plast Reconstr Anesth Surg 2011; 64:1424–1429. 7. Brenner E, Schoeller T. Masseteric nerve: a possible donor for facial nerve anastomosis? Clin Anat 1998; 11:396–400. 8. 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; 62:1580–1588. 9. Borschel GH, Kawamura DH, Kasukurthi R, et al. The motor nerve to the masseter muscle: an anatomic and histomorphometric study to facilitate its use in facial reanimation. J Plast Reconstr Anesth Surg 2012; 65:363– 366. 10. Collar RM, Byrne PJ, Boahene KD. The subzygomatic triangle: rapid, minimally & invasive identification of the masseteric nerve for facial reanimation. Plast Reconstr Surg 2013; 132:183–188. A great description of an easy, anatomically based way to quickly and efficiently identify the masseteric nerve. 11. Korte W. Nerve grafting: facial nerve on hypoglossal. Dtsch Med Wochenschr 1903; 17:293–295. [in German] 12. Atlas MD, Lowinger DS. A new technique for hypoglossal–facial nerve repair. Laryngoscope 1997; 107:984–991. 13. Conley J, Baker DC. Hypoglossal–facial nerve anastomosis for reinnervation of the paralyzed face. Plast Reconstr Surg 1979; 63:63–72. 14. Koh KS, Kim J, Kim CJ, et al. Hypoglossal–facial crossover in facial-nerve palsy: pure end-to-side anastomosis technique. Br J Plast Surg 2002; 55:25– 31. 15. May M, Sobol SM, Mester SJ. Hypoglossal–facial nerve interpositional-jump graft for facial reanimation without tongue atrophy. Otolaryngol Head Neck Surg 1991; 104:818–825. 16. Noah EM, Williams A, Jorgenson C, et al. End-to-side neurorrhaphy: a histologic and morphometric study of axonal sprouting into an end-to-side nerve graft. J Reconstr Microsurg 1997; 13:99–106. 17. Pensak ML, Jackson CG, Glasscock ME 3rd, Gulya AJ. Facial reanimation with the VII–XII anastomosis: analysis of the functional and psychologic results. Otolaryngol Head Neck Surg 1986; 94:305–310. 18. Viterbo F, Trindade JC, Hoshino K, Mazzoni Neto A. Latero-terminal neurorrhaphy without removal of the epineural sheath. Experimental study in rats. Rev Paul Med 1992; 110:267–275. 19. Spira M. Anastomosis of masseteric nerve to lower division of facial nerve for correction of lower facial paralysis. Preliminary report. Plast Reconstr Surg 1978; 61:330–334. 20. Hontanilla B, Marre D. Comparison of hemihypoglossal nerve versus masseteric nerve transpositions in the rehabilitation of short-term facial paralysis using the Facial Clima evaluating system. Plast Reconstr Surg 2012; 130:662e–672e.
21. 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; 36:235–240. An excellent review of the techniques and use of the masseteric–facial nerve direct coaptation in the setting of additional cross-face nerve grafting for maximizing the functional and cosmetic outcomes. 22. Bermudez LE, Nieto LE. Masseteric–facial nerve anastomosis: case report. J Reconstr Microsurg 2004; 20:25–30. 23. Biglioli F, Frigerio A, Colombo V, et al. Masseteric–facial nerve anastomosis & for early facial reanimation. J Craniomaxillofac Surg 2012; 40:149–155. This study entails good reasoning, description of their procedure and outcomes with long enough follow-up to draw conclusions regarding direct masseteric– facial nerve transfers. 24. Sforza C, Frigerio A, Mapelli A, et al. Facial movement before and after masseteric–facial nerves anastomosis: a three-dimensional optoelectronic pilot study. J Craniomaxillofac Surg 2012; 40:473–479. 25. Bianchi B, Ferri A, Ferrari S, et al. The masseteric nerve: a versatile power source in facial animation techniques. Br J Oral Maxillofac Surg 2014; 52:264–269. 26. Terzis JK, Noah ME. Analysis of 100 cases of free-muscle transplantation for facial paralysis. Plast Reconstr Surg 1997; 99:1905–1921. 27. Hontanilla B, Marre D, Cabello A. Masseteric nerve for reanimation of the && smile in short-term facial paralysis. Br J Oral Maxillofac Surg 2014; 52:118– 123. The largest single review of patients undergoing direct masseteric –facial nerve transfers and excellent quantitative data reviewing not only total movement, but also the speed of that movement and how it compares to the unaffected side. 28. Terzis JK. Babysitters. An exciting new concept in facial reanimation. In: Castro D, editor. 6th International Symposium on the facial nerve. Rio de Janeiro, Brazil: Kugler & Ghedini; 1988. 29. Kalantarian B, Rice DC, Tiangco DA, Terzis JK. Gains and losses of the XII–VII component of the ‘baby-sitter’ procedure: a morphometric analysis. J Reconstr Microsurg 1998; 14:459–471. 30. Mersa B, Tiangco DA, Terzis JK. Efficacy of the ‘baby-sitter’ procedure after prolonged denervation. J Reconstr Microsurg 2000; 16:27–35. 31. Terzis JK, Tzafetta K. The ‘babysitter’ procedure: minihypoglossal to facial nerve transfer and cross-facial nerve grafting. Plast Reconstr Surg 2009; 123:865–876. 32. Terzis JK, Tzafetta K. ‘Babysitter’ procedure with concomitant muscle transfer in facial paralysis. Plast Reconstr Surg 2009; 124:1142–1156. 33. Faria JC, Scopel GP, Ferreira MC. Facial reanimation with masseteric nerve: babysitter or permanent procedure? Preliminary results. Ann Plast Surg 2010; 64:31–34. 34. Bae YC, Zuker RM, Manktelow RT, Wade S. A comparison of commissure excursion following gracilis muscle transplantation for facial paralysis using a cross-face nerve graft versus the motor nerve to the masseter nerve. Plast Reconstr Surg 2006; 117:2407–2413. 35. Zuker RM, Goldberg CS, Manktelow RT. Facial animation in children with Mobius syndrome after segmental gracilis muscle transplant. Plast Reconstr Surg 2000; 106:1–8; discussion 9. 36. Hadlock TA, Malo JS, Cheney ML, Henstrom DK. Free gracilis transfer for smile in children: the Massachusetts Eye and Ear Infirmary Experience in excursion and quality-of-life changes. Arch Facial Plast Surg 2011; 13:190– 194. 37. Faria JC, Scopel GP, Busnardo FF, Ferreira MC. Nerve sources for facial reanimation with muscle transplant in patients with unilateral facial palsy: clinical analysis of 3 techniques. Ann Plast Surg 2007; 59:87–91. 38. Manktelow RT, Tomat LR, Zuker RM, Chang M. Smile reconstruction in adults with free muscle transfer innervated by the masseter motor nerve: effectiveness and cerebral adaptation. Plast Reconstr Surg 2006; 118:885–899. 39. Bianchi B, Copelli C, Ferrari S, et al. Facial animation with free-muscle transfer innervated by the masseter motor nerve in unilateral facial paralysis. J Oral Maxillofac Surg 2010; 68:1524–1529. 40. Bianchi B, Copelli C, Ferrari S, et al. Use of the masseter motor nerve in facial animation with free muscle transfer. Br J Oral Maxillofac Surg 2012; 50:650– 653. 41. Eisenhardt SU, Thiele JR, Stark GB, Bannasch H. Comparison of cross face nerve graft with masseteric nerve as donor nerves for free functional muscle transfers in facial reanimation surgery. Handchir Mikrochir Plast Chir 2013; 45:223–228. 42. Hontanilla B, Marre D, Cabello A. Facial reanimation with gracilis muscle & transfer neurotized to cross-facial nerve graft versus masseteric nerve: a comparative study using the FACIAL CLIMA evaluating system. Plast Reconstr Surg 2013; 131:1241–1252. An excellent large review comparing the outcomes of gracilis muscle transfer between those powered by a cross-face graft and the masseteric nerve. Quantitative measurements include total excursion distance and speed of movement compared to unaffected side. 43. Dellon AL, Mackinnon SE. Segmentally innervated latissimus dorsi muscle. Microsurgical transfer for facial reanimation. J Reconstr Microsurg 1985; 2:7–12. 44. Terzis JK. Pectoralis minor: a unique muscle for correction of facial palsy. Plast Reconstr Surg 1989; 83:767–776. &&
1068-9508 ß 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
www.co-otolaryngology.com
289
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Facial plastic surgery 45. 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. 46. Vakharia KT, Henstrom D, Plotkin SR, et al. Facial reanimation of patients with neurofibromatosis type 2. Neurosurgery 2012; 70:237–243. 47. Hontanilla B, Marre D. Differences between sexes in dissociation and spontaneity of smile in facial paralysis reanimation with the masseteric nerve. Head Neck 2013. [Epub ahead of print] 48. Lifchez SD, Matloub HS, Gosain AK. Cortical adaptation to restoration of smiling after free muscle transfer innervated by the nerve to the masseter. Plast Reconstr Surg 2005; 115:1472–1479; discussion 1480–1482.
290
www.co-otolaryngology.com
49. Marre D, Hontanilla B. Brain plasticity in Mobius syndrome after unilateral muscle transfer: case report and review of the literature. Ann Plast Surg 2012; 68:97–100. 50. Rozen S, Harrison B. Involuntary movement during mastication in patients with long-term facial paralysis reanimated with a partial gracilis free neuromuscular flap innervated by the masseteric nerve. Plast Reconstr Surg 2013; 132: 110e–116e. 51. Biglioli F, Colombo V, Tarabbia F, et al. Double innervation in free-flap surgery for long-standing facial paralysis. J Plast Reconstr Aesthet Surg 2012; 65:1343–1349. 52. Klebuc MJ. Facial reanimation using the masseter-to-facial nerve transfer. Plast Reconstr Surg 2011; 127:1909–1915.
Volume 22 Number 4 August 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
