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Facial paralysis and the role of free muscle transplantation
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ANNPLA-1146; No. of Pages 10 Annales de chirurgie plastique esthétique (2015) xxx, xxx—xxx
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Facial paralysis and the role of free muscle transplantation ´ re ˆ t de la greffe musculaire libre La paralysie faciale et l’inte R.M. Zuker The Hospital for Sick Children, Staff surgeon, 555 University Avenue, ON M5G 1X8, Toronto, Canada
KEYWORDS Facial paralysis; Muscle transplantation; Symmetrical smile; Cross face nerve graft; Muscle reinnervation
MOTS CLÉS Paralysie faciale ; Greffe musculaire libre ; Symétrie du sourire ; Greffe de nerf facial controlatéral ; Réinnervation musculaire
Summary Facial paralysis can have significant functional, psychological and aesthetic concerns that alter the lives of our patients. These effects can be functional, affecting the eye, nose and mouth, or aesthetic, affecting the symmetry of the face and particularly the mimetic function of smile. Several reanimation procedures have been described to address this. In this chapter, we will outline our technique for reanimation utilizing segmental gracilis muscle transplants to the face. These are innervated either by the contralateral normal 7th nerve via a cross face nerve graft, or a different ipsilateral motor where no 7th nerve is available or would not produce the required result. The other ipsilateral motor that we have found extremely effective is the motor nerve to masseter. This can power a segmental gracilis muscle transplant and lead to excursion that is near normal. These techniques will be described in detail. # 2015 Published by Elsevier Masson SAS. Résumé La paralysie faciale est susceptible d’avoir des répercussions significatives sur les plans fonctionnel, psychologique et esthétique qui transforment l’existence de nos patients. De tels retentissements peuvent être fonctionnels par rapport aux yeux, au nez ou la bouche ; ils sont également parfois esthétiques, altérant la symétrie du visage et, plus particulièrement, la fonction mimétique du sourire. Plusieurs procédures de réanimation ont été mises au point en vue d’atténuer le problème. Dans ce chapitre, nous allons décrire dans les grandes lignes notre technique de réanimation qui consiste à utiliser le transfert musculaire libre partiel de gracilis. L’innervation de ces transferts libres se fait soit par le VII controlatéral, soit par le nerf massétérin ipsilatéral lorsque le facial n’est pas utilisable. # 2015 Publié par Elsevier Masson SAS.
E-mail address: [email protected]. http://dx.doi.org/10.1016/j.anplas.2015.06.001 0294-1260/# 2015 Published by Elsevier Masson SAS.
Please cite this article in press as: Zuker R.M. Facial paralysis and the role of free muscle transplantation. Ann Chir Plast Esthet (2015), http://dx.doi.org/10.1016/j.anplas.2015.06.001
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Facial paralysis can lead to a number of functional, psychological and aesthetic concerns. There is a wide range of presentations, from complete facial paralysis (Fig. 1) to varying degrees of incomplete facial paralysis, with further subdivisions based on the section of the face that is involved. The most common form in children is unilateral congenital facial paralysis, often called ‘‘developmental palsy’’ (Fig. 2). This usually involves all components of the face but may be isolated to only the buccal segment or the mandibular segment (Fig. 3). Facial paralysis can also be bilateral in children with the most common form being that seen in Moebius syndrome (Fig. 4). These clinical presentations [1] will be discussed in detail, as well as our preferred method of treatment. The affects of facial paralysis involve orifice control for the eye, nose and mouth, as well as facial expression. The lack of orifice control for the eye can lead to corneal exposure, keratopathy and potential visual loss. The orifice control relating to the nose can cause difficulties breathing with lack of normal opening of the involved nostril. The lack of orifice control for the mouth can affect the symmetry of the face with drooping of the involved side, as well as problems related to speech, chewing and oral competence leading to drooling. In some cases, the lack of dental protection can lead to dental decay. The mimetic function, however, of the facial nerve is critical for social interactions. Non verbal communication is conveyed by facial expression and is essential for normal interpersonal interactions. A smile invokes a smile in others and conveys feelings that cannot be transmitted in any other way. Consequently, a spontaneous dynamic smile is critical for personal interactions (Fig. 5). We try to approach the reconstruction of facial paralysis with this spontaneous dynamic smile in mind. A smile consists of two components. One of the physical movement of the corners of the mouth which originates
Figure 1 surgery.
Complete facial paralysis following brain tumour
Figure 2
Congenital developmental palsy — incomplete.
intracranially from the 7th nerve nucleus. The other component, however, is the emotional expression of joy which comes from the frontal lobe. It is a combination of these two components that lead to a normal spontaneous smile. This is effected through the 7th nerve and for this reason, we prefer
Figure 3 drome’’.
Mandibular branch paralysis — ‘‘Crying facies syn-
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Figure 4
Bilateral facial paralysis in Moebius syndrome.
to use a 7th nerve based reconstruction if possible. In developmental palsy, this is usually our preferred method using the normal 7th nerve as our power source. There are a number of reanimation procedures available for the treatment of facial paralysis. Firstly, nerve based reconstruction using direct nerve repair, nerve grafts and transfers are helpful if timing permits. The muscle unfortunately will deteriorate after about 1 year of lack of innervation. The motor end plates lose their ability to function and the muscle is rendered non-reinnervatable. However, prior to 1 year, a nerve-based reconstruction may be possible. If there is no usable musculature in the face, muscle transfers can be applied. Regional muscle transfers have been utilized with great success [2,3]. However, they can lead to contour irregularities and limited excursion. This is particularly true with the masseter transfer which also has an inappropriate lateral direction of contraction. Our preference is to replace the zygomaticus major and minor muscle complex activity with a free muscle transplant. These are technically more difficult but they can be positioned where one wants without the limitation of the vascular or neural pedicle. Consequently, the vector of movement is more natural and the extent of excursion approaches normal [4]. The goal of facial paralysis reconstruction is to produce a normal appearance. This involves symmetry at rest with minimal distortions and active movement of the oral commissures in the appropriate direction and the appropriate excursion. Both form and function are essential (Fig. 6A, B). The keys to success in muscle transplantation will be discussed in detail but involve: muscle positioning; reduction of bulk;
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Figure 5 The lack of a symmetrical smile makes interpersonal communication awkward.
strong motor input; accurate tension.
Patient selection In the young patient, who has a minimal droop, we believe we can get adequate excursion with a cross face nerve graft followed by a muscle transplant. However, in the older patient with excessive droop, we believe it is preferable to do a muscle transplant powered by a more powerful nerve such as the motor nerve to masseter. When there is no 7th nerve bilaterally, muscle transplantation can also be carried out, but must be powered by a different motor. Again in these situations, we prefer to use the motor nerve to masseter.
Cross face nerve graft — Gracilis muscle transplant combination In the younger individual with unilateral facial paralysis, we prefer the cross face nerve graft/muscle transplant combination [5]. In the cross face nerve graft procedure, the normal side is explored. We do this with an open approach through a pre-auricular incision. The meshwork of the 7th nerve in the mid face helps us to select an appropriate branch and importantly to preserve an alternate branch (Fig. 7). This is done with a nerve stimulator under direct vision. The nerve that we want typically lies midway between the root of the helix and the oral commissure. A bipolar nerve stimulator is used and a facial nerve map is produced. Once the appropriate nerve is selected (Fig. 8), we make a tunnel
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Figure 6 A. Preoperative bilateral facial paralysis (Moebius syndrome). B. Postoperative following bilateral segmental gracilis muscle transplantation to the face innervated by the motor nerve to masseter.
just above the periosteum, across the upper lip to the buccal sulcus on the involved side. We prefer to use the proximal component of the sural nerve just distal to the knee for our nerve graft [6]. We procure the sural nerve through a transverse incision just below the popliteal fossa. Our dissection goes through the fascia and the nerve is identified. It is dissected proximally to the popliteal fossa where it is divided. We then use a nerve stripper to strip distally to about the mid calf. Here another incision is made, the freed nerve is divided and withdrawn (Fig. 9). Typically, it has no branches and is of excellent size match for the branch of the facial nerve that we have selected. The nerve is placed through the tunnel (Fig. 10). The end in the buccal sulcus is marked with a prolene suture and a hemoclip so that it can be easily identified at the next operation. The branch of the
Figure 7 Cross face nerve graft, exploration of normal side, facial nerve mapping and selection of appropriate segment of facial nerve.
facial nerve that we had selected is divided and then under high-powered magnification coapted to the sural nerve graft. Typically, the size match is excellent if the proximal component of the sural nerve is utilized. The incisions are then closed with absorbable sutures. No drains are required.
Muscle transplant procedure We wait approximately 9 months for the activity of the facial nerve to grow across the graft. After 9 months, it is ready to power our new muscle transplant. If we were to do both the nerve graft and the muscle transplant at the same time, the muscle would atrophy excessively and not function as well. Thus, 1 year later, we then proceed with the muscle transplant procedure. The preoperative planning for this procedure is essential. First, we must assess the vector of
Figure 8
Appropriate branch of facial nerve being stimulated.
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Figure 9
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Sural nerve procurement.
movement of the normal side. We also assess the location of movement relative to the oral commissure, that is to say the site of pull at the oral commissure (Fig. 11). We try very hard to replicate the normal side as best possible. After our preoperative planning is complete, we use an open approach through a preauricular incision and a submandibular extension on the involved paralyzed side. We carry the dissection medially towards the oral commissure at the level of the deep fat. We identify the area around the mouth and upper lip, sometimes with the aid of traction intraorally. We place our anchoring sutures very carefully into the oral commissure and upper lip. If there is excessive droop, we place an additional suture into the lower lip as well so that we can elevate the lower lip to its normal position relative to the normal side. Typically, we will place one suture in the oral commissure and two in the upper lip, and possibly one in the lower lip. With traction on these sutures, we assess the movement that is created and the future location of the pull of our muscle transplant (Fig. 12). This is one of the most important parts of the procedure, to get our anchoring sutures in exactly the right location. We also identify the facial artery and facial vein as these will be used to revascularize our muscle transplant. To minimize bulk, we remove the buccal fat pad as well as a portion of the deep fat that would lie directly on top of the muscle.
Figure 10 Sural nerve graft in place and ends placed on green background, ready for coaptation to facial nerve on normal side and secured to periosteum in upper buccal sulcus on involved side.
Figure 11 Preoperative planning prior to muscle transplant procedure noting vector, point of pull and facial artery.
Muscle tension In order to get the correct tension, we measure the distance from the oral commissure to the root of the helix, as this will be the length of our functioning muscle. We add 1 cm on each end for suturing and this will be the length of muscle that is procured from the thigh. Attention is then turned to the
Figure 12 Assessment of predicted excursion with traction on anchoring sutures.
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R.M. Zuker sutures. Once the muscle is secured, then the anchoring sutures are tied down and the muscle transplant is locked in place. Typically, we use a No. 1 Vicryl suture for our anchoring sutures. The muscle is then revascularized through microvascular anastomoses to the facial artery and vein. The motor nerve to gracilis is tunneled into the upper lip so that it lies next to our previously placed cross face nerve graft. An upper buccal sulcus incision is used to access the cross face nerve graft and prepare it for coaptation to the motor nerve to gracilis. This nerve repair is done under high magnification under the operating microscope intraorally.
Securing the muscle
In order to secure the muscle appropriately into the commissure and upper lip, we have a line of mattress sutures going across the end of the muscle that will be inserted into the commissure and upper lip. This line of mattress sutures will lock our anchoring sutures so that they will not slide through the muscle (Fig. 14). If we have four anchoring sutures, we utilize five mattress sutures. The anchoring suture goes into the muscle behind the mattress suture and then back into the oral commissure or upper lip very close to where the original one was. It then comes back through the muscle proximal to the next mattress suture just above the first. These are done sequentially so that the anchoring sutures are all locked behind this row of mattress
Now that the muscle is positioned into the oral commissure and upper lip, revascularized and reinnervated, we then secure the proximal portion to the temporal fascia. We do this with heavy vicryl mattress sutures, placing the muscle under the appropriate tension. This generally puts the oral commissure even with the normal side and with only slight tension (Fig. 15). It is not overcorrected as this will distort the mouth, nor is it undercorrected, as it will not provide for the appropriate excursion. After this, the cheek flap is repositioned and closed. We typically use a small Penrose drain, exiting from a post auricular separate stab incision. The drain lies close to the vascular anastomosis, but not adherent to it. After the cross face nerve graft muscle transplant combination procedures, we typically see muscle activity beginning at about 4 months post-muscle transplant. We then have the patient enter into an exercise program with biofeedback. They try to smile in front of a mirror and observe the activity of the reconstructed oral commissure. They try to increase the excursion so that it is as close to normal as possible, and also try to get it to become as spontaneous as possible. As we are utilizing the 7th nerve, spontaneity is generally not a problem and the muscle is activated at the same time as the normal side. Under close scrutiny, one can see a slight time delay as the neural activity moves across the cross face nerve graft from the normal side and into the muscle on the reconstructed side.
Figure 14 Gracilis being inserted with anchoring sutures locking behind row of mattress sutures.
Figure 15 Muscle transplant in place, revascularized and ready for securing sutures in temporal fascia under appropriate tension.
Figure 13 Segmental gracilis muscle procurement. Approximately, one third of circumference of muscle utilized.
thigh. An upper inner thigh incision is made and the gracilis muscle is encountered. Approximately one third of the circumference of the gracilis muscle is utilized with the neurovascular bundle at the center of our procurement (Fig. 13).
Muscle locking
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We have been very pleased with the results of this combination surgery (Fig. 16A—D). It is imperative, however, to use a significant amount of facial nerve on the normal side in order to provide adequate motor input. It is also important to only use a small segment of gracilis in order to avoid excess bulk. The results of unilateral facial paralysis reconstruction utilizing cross face nerve graft and muscle transplant combination surgeries can be seen in the following images.
We have tried various motor nerves, such as the hypoglossal, the accessory, but feel that the motor nerve to masseter is by far the best. It is a powerful nerve that will provide excellent excursion to the muscle transplant. We feel it also is in a better position to allow for spontaneity through cortical plasticity [7]. The muscle transplant procedure is essentially the same as that previously described. A pre-auricular incision with a submandibular extension is made. The dissection proceeds anteriorly toward the oral commissure. The plane is at the lower level of the deep fat. There is often no facial musculature to guide one in the plane of dissection. This is the case in Moebius syndrome, where no muscle has developed. In this situation, it is helpful to use the plane of the facial artery to guide the dissection. This will lead the operator in the correct plane without going too deep into the mucosa or too superficial into the dermis. We continue the dissection at the level of the facial artery to the oral commissure and upper lip. Here again, we place our anchoring sutures into
Muscle transplant innervated by the motor nerve to masseter In bilateral facial paralysis, there is no facial nerve available, and consequently, the cross face nerve graft procedure is not possible. In these situations, we have still found the segmental gracilis muscle transplant to be most useful. However, it needs to be innervated by a different motor nerve.
Figure 16 smiling.
Unilateral facial paralysis. A. Preoperative: at rest. B. Preoperative: smiling. C. Postoperative: at rest. D. Postoperative:
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the oral commissure and upper lip and do our measurements. The facial artery and vein are appropriately prepared.
The motor nerve to masseter The motor nerve to masseter is found by carrying the dissection deep through the masseter muscle to almost its under surface. It lies in the plane between the middle component and the deep component of the musculature. We utilize the Borschel rule to find the motor nerve to masseter. This is 3 cm anterior to the tragus and 1 cm inferior and deep to the mid component of the three lobes of the masseter muscle (Fig. 17) [8]. The nerve is identified as a white structure coursing downward and anteriorly toward the oral commissure. It is confirmed by the use of the electrostimulator. It is dissected into the musculature, divided at its point of branching and then brought upward to the surface of the muscle. Thus, it is in a better position for nerve coaptation to the motor nerve to gracilis. We find it helpful to remove the buccal fat pad. This aids in the dissection of the facial vessels and also reduces bulk in the cheek. We remove not only the buccal fat pad but also a small amount of the deep fat that will lie on top of the actual muscle transplant. The muscle is positioned as previously described and the vascular anastomoses are carried out. Then, the motor nerve to masseter is coapted to the motor nerve of the gracilis. The muscle is repositioned and secured in the temporal fascia, as previously described under appropriate tension (Fig. 18). Again, a small Penrose drain is utilized through a separate post-auricular stab incision. In bilateral cases, we do one side at a time and space them at least 3 months apart. We do this to allow the first side to become active so that we can see exactly the vector of pull and the location of the insertion. Thus, we are able to replicate this as best possible when we do the second side. We wait at least 3 months before doing the second side in bilateral cases to assess movement but could potentially wait longer depending on the wishes of the patient.
Reinnervation schedule After about 10 weeks, the muscle is reinnervated when the motor nerve to masseter is used. We again institute a
Figure 17
Finding the motor nerve to masseter.
rehabilitation program with smiling and biofeedback. Here, the biofeedback is extremely important in order to not only gain adequate excursion but also to create a degree of spontaneity. With ongoing therapy in the well-motivated patient, many do go on to have a spontaneous smile (Fig. 19A—E). However, this does not happen automatically but only with a frequent exercise program utilizing biofeedback. When the motor nerve to masseter is utilized, initially the patients have to bite down to activate the muscle. This is phase I and it occurs at about 10 to 12 weeks after surgery. Very quickly however, they move on to phase 2 where they are able to activate the muscle without moving the jaw. Then, with the rehab described and the biofeedback, they sometimes progress onto phase 3 where the activity becomes spontaneous when a smile is needed.
Discussion Muscle transplantation for facial paralysis is a very technically dependent procedure. It must be carried out precisely and each step is critical for its success. We feel the key elements are positioning the muscle appropriately and maintaining it in that location. This involves very careful suture placement and the technique described to limit any pulling through of the suture. The second critical factor is to reduce bulk. We do this by only using a small segment of the gracilis muscle, approximately 1/3 of the circumference. We also remove the buccal fat pad and some of the subcutaneous fat that will lie over the muscle. The third component is to provide a strong motor input. We do this by selecting a significant portion of the facial nerve on the normal side to coapt to a thin sural nerve graft. We try to get as much axon density into the nerve graft as possible. We utilize the motor nerve to masseter in bilateral cases, which provides enough power for normal muscle excursion. The fourth key to success is to provide appropriate tension on the muscle. This involves placing the muscle under a slight degree of tension so that the commissure just barely moves. With these four critical components, we have been very impressed with the results of muscle transplantation for facial paralysis reconstruction. We do rely on cortical plasticity when the motor nerve to masseter is utilized, fortunately in many cases that
Figure 18 Segmental gracilis muscle in position, revascularized and reinnervated by the motor nerve to masseter.
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Figure 19 Bilateral facial paralysis (Moebius syndrome). A. Preoperative: at rest. B. Preoperative: attempting a smile. C. Postoperative: at rest. D. Postoperative: small smile. E. Postoperative: full smile.
transference and spontaneity has occurred. However, there have been some where this spontaneity has not occurred and the required smile has to be thought about to happen. The reasons for this are under further investigation [9]. We believe that the motor nerve to masseter is an excellent choice in bilateral cases of facial paralysis. It is also appropriate when we would anticipate inadequate excursion because of a very powerful smile on the normal side. We also feel it is helpful in a failed previous procedure, where one does not want to dissect once again the normal facial nerve. In children with unilateral facial paralysis that is of the congenital type, our preference is still the cross face nerve graft/muscle transplant combination. In conclusion then, facial paralysis can have significant effects from a functional, psychological and aesthetic viewpoint. Reconstruction is possible. We feel that muscle transplantation can yield excellent results providing natural appearing oral commissure movement and excursion. The muscle can be powered either by a cross face nerve graft in unilateral cases, or by the motor nerve to masseter in bilateral cases. This surgical intervention can lead to
improved oral continence, clearer speech, improved facial symmetry and perhaps, most important, a restored smile in acquired cases and a created smile in congenital cases.
Disclosure of interest The author declares that he has no conflicts of interest concerning this article.
References [1] Westin LM, Zuker RM. A new classification system for facial paralysis in the clinical setting. J Craniofac Surg 2003;14:672. [2] Labbe D, Huault M. Lengthening temporalis myoplasty and lip reanimation. Plast Reconstr Surg 2000;105:1289. [3] Labbe D. Myoplastic d’allongement du temporal V.2 et réanimation des lèvres. Ann Chir Plast Esthet 2009;54:571. [4] 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 masseter. Plast Reconstr Surg 2006;117:2407.
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10 [5] Zuker RM, Gur E, Hussain G, Manktelow RT. Facial paralysis. Plast Surg 2013;3:278. [6] Manktelow RT, Zuker RM. Cross-facial nerve graft — The long and short graft: the first stage for microneurovascular muscle transfer. Oper Tech Plast Reconstr Surg 1999;6(3)174—9. [7] Zuker RM, Goldberg CS, Manktelow RT. Facial animation in children with moebius syndrome after segmental gracilis muscle transplant. Plast Reconstr Surg 2000;106:1.
R.M. Zuker [8] Borschel G, Zuker RM, Kawamura DH, Kasukurthi R, Hunter DA, Woo AS. The motor nerve to the masseter muscle: anatomic and histomorphometric study to facilitate its use in facial reanimation. Plast Reconstr Aesthet Surg 2012;363—6. [9] 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.
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ANNPLA-1146; No. of Pages 10 Annales de chirurgie plastique esthétique (2015) xxx, xxx—xxx
Available online at
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Facial paralysis and the role of free muscle transplantation ´ re ˆ t de la greffe musculaire libre La paralysie faciale et l’inte R.M. Zuker The Hospital for Sick Children, Staff surgeon, 555 University Avenue, ON M5G 1X8, Toronto, Canada
KEYWORDS Facial paralysis; Muscle transplantation; Symmetrical smile; Cross face nerve graft; Muscle reinnervation
MOTS CLÉS Paralysie faciale ; Greffe musculaire libre ; Symétrie du sourire ; Greffe de nerf facial controlatéral ; Réinnervation musculaire
Summary Facial paralysis can have significant functional, psychological and aesthetic concerns that alter the lives of our patients. These effects can be functional, affecting the eye, nose and mouth, or aesthetic, affecting the symmetry of the face and particularly the mimetic function of smile. Several reanimation procedures have been described to address this. In this chapter, we will outline our technique for reanimation utilizing segmental gracilis muscle transplants to the face. These are innervated either by the contralateral normal 7th nerve via a cross face nerve graft, or a different ipsilateral motor where no 7th nerve is available or would not produce the required result. The other ipsilateral motor that we have found extremely effective is the motor nerve to masseter. This can power a segmental gracilis muscle transplant and lead to excursion that is near normal. These techniques will be described in detail. # 2015 Published by Elsevier Masson SAS. Résumé La paralysie faciale est susceptible d’avoir des répercussions significatives sur les plans fonctionnel, psychologique et esthétique qui transforment l’existence de nos patients. De tels retentissements peuvent être fonctionnels par rapport aux yeux, au nez ou la bouche ; ils sont également parfois esthétiques, altérant la symétrie du visage et, plus particulièrement, la fonction mimétique du sourire. Plusieurs procédures de réanimation ont été mises au point en vue d’atténuer le problème. Dans ce chapitre, nous allons décrire dans les grandes lignes notre technique de réanimation qui consiste à utiliser le transfert musculaire libre partiel de gracilis. L’innervation de ces transferts libres se fait soit par le VII controlatéral, soit par le nerf massétérin ipsilatéral lorsque le facial n’est pas utilisable. # 2015 Publié par Elsevier Masson SAS.
E-mail address: [email protected]. http://dx.doi.org/10.1016/j.anplas.2015.06.001 0294-1260/# 2015 Published by Elsevier Masson SAS.
Please cite this article in press as: Zuker R.M. Facial paralysis and the role of free muscle transplantation. Ann Chir Plast Esthet (2015), http://dx.doi.org/10.1016/j.anplas.2015.06.001
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Facial paralysis can lead to a number of functional, psychological and aesthetic concerns. There is a wide range of presentations, from complete facial paralysis (Fig. 1) to varying degrees of incomplete facial paralysis, with further subdivisions based on the section of the face that is involved. The most common form in children is unilateral congenital facial paralysis, often called ‘‘developmental palsy’’ (Fig. 2). This usually involves all components of the face but may be isolated to only the buccal segment or the mandibular segment (Fig. 3). Facial paralysis can also be bilateral in children with the most common form being that seen in Moebius syndrome (Fig. 4). These clinical presentations [1] will be discussed in detail, as well as our preferred method of treatment. The affects of facial paralysis involve orifice control for the eye, nose and mouth, as well as facial expression. The lack of orifice control for the eye can lead to corneal exposure, keratopathy and potential visual loss. The orifice control relating to the nose can cause difficulties breathing with lack of normal opening of the involved nostril. The lack of orifice control for the mouth can affect the symmetry of the face with drooping of the involved side, as well as problems related to speech, chewing and oral competence leading to drooling. In some cases, the lack of dental protection can lead to dental decay. The mimetic function, however, of the facial nerve is critical for social interactions. Non verbal communication is conveyed by facial expression and is essential for normal interpersonal interactions. A smile invokes a smile in others and conveys feelings that cannot be transmitted in any other way. Consequently, a spontaneous dynamic smile is critical for personal interactions (Fig. 5). We try to approach the reconstruction of facial paralysis with this spontaneous dynamic smile in mind. A smile consists of two components. One of the physical movement of the corners of the mouth which originates
Figure 1 surgery.
Complete facial paralysis following brain tumour
Figure 2
Congenital developmental palsy — incomplete.
intracranially from the 7th nerve nucleus. The other component, however, is the emotional expression of joy which comes from the frontal lobe. It is a combination of these two components that lead to a normal spontaneous smile. This is effected through the 7th nerve and for this reason, we prefer
Figure 3 drome’’.
Mandibular branch paralysis — ‘‘Crying facies syn-
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Figure 4
Bilateral facial paralysis in Moebius syndrome.
to use a 7th nerve based reconstruction if possible. In developmental palsy, this is usually our preferred method using the normal 7th nerve as our power source. There are a number of reanimation procedures available for the treatment of facial paralysis. Firstly, nerve based reconstruction using direct nerve repair, nerve grafts and transfers are helpful if timing permits. The muscle unfortunately will deteriorate after about 1 year of lack of innervation. The motor end plates lose their ability to function and the muscle is rendered non-reinnervatable. However, prior to 1 year, a nerve-based reconstruction may be possible. If there is no usable musculature in the face, muscle transfers can be applied. Regional muscle transfers have been utilized with great success [2,3]. However, they can lead to contour irregularities and limited excursion. This is particularly true with the masseter transfer which also has an inappropriate lateral direction of contraction. Our preference is to replace the zygomaticus major and minor muscle complex activity with a free muscle transplant. These are technically more difficult but they can be positioned where one wants without the limitation of the vascular or neural pedicle. Consequently, the vector of movement is more natural and the extent of excursion approaches normal [4]. The goal of facial paralysis reconstruction is to produce a normal appearance. This involves symmetry at rest with minimal distortions and active movement of the oral commissures in the appropriate direction and the appropriate excursion. Both form and function are essential (Fig. 6A, B). The keys to success in muscle transplantation will be discussed in detail but involve: muscle positioning; reduction of bulk;
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Figure 5 The lack of a symmetrical smile makes interpersonal communication awkward.
strong motor input; accurate tension.
Patient selection In the young patient, who has a minimal droop, we believe we can get adequate excursion with a cross face nerve graft followed by a muscle transplant. However, in the older patient with excessive droop, we believe it is preferable to do a muscle transplant powered by a more powerful nerve such as the motor nerve to masseter. When there is no 7th nerve bilaterally, muscle transplantation can also be carried out, but must be powered by a different motor. Again in these situations, we prefer to use the motor nerve to masseter.
Cross face nerve graft — Gracilis muscle transplant combination In the younger individual with unilateral facial paralysis, we prefer the cross face nerve graft/muscle transplant combination [5]. In the cross face nerve graft procedure, the normal side is explored. We do this with an open approach through a pre-auricular incision. The meshwork of the 7th nerve in the mid face helps us to select an appropriate branch and importantly to preserve an alternate branch (Fig. 7). This is done with a nerve stimulator under direct vision. The nerve that we want typically lies midway between the root of the helix and the oral commissure. A bipolar nerve stimulator is used and a facial nerve map is produced. Once the appropriate nerve is selected (Fig. 8), we make a tunnel
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Figure 6 A. Preoperative bilateral facial paralysis (Moebius syndrome). B. Postoperative following bilateral segmental gracilis muscle transplantation to the face innervated by the motor nerve to masseter.
just above the periosteum, across the upper lip to the buccal sulcus on the involved side. We prefer to use the proximal component of the sural nerve just distal to the knee for our nerve graft [6]. We procure the sural nerve through a transverse incision just below the popliteal fossa. Our dissection goes through the fascia and the nerve is identified. It is dissected proximally to the popliteal fossa where it is divided. We then use a nerve stripper to strip distally to about the mid calf. Here another incision is made, the freed nerve is divided and withdrawn (Fig. 9). Typically, it has no branches and is of excellent size match for the branch of the facial nerve that we have selected. The nerve is placed through the tunnel (Fig. 10). The end in the buccal sulcus is marked with a prolene suture and a hemoclip so that it can be easily identified at the next operation. The branch of the
Figure 7 Cross face nerve graft, exploration of normal side, facial nerve mapping and selection of appropriate segment of facial nerve.
facial nerve that we had selected is divided and then under high-powered magnification coapted to the sural nerve graft. Typically, the size match is excellent if the proximal component of the sural nerve is utilized. The incisions are then closed with absorbable sutures. No drains are required.
Muscle transplant procedure We wait approximately 9 months for the activity of the facial nerve to grow across the graft. After 9 months, it is ready to power our new muscle transplant. If we were to do both the nerve graft and the muscle transplant at the same time, the muscle would atrophy excessively and not function as well. Thus, 1 year later, we then proceed with the muscle transplant procedure. The preoperative planning for this procedure is essential. First, we must assess the vector of
Figure 8
Appropriate branch of facial nerve being stimulated.
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Figure 9
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Sural nerve procurement.
movement of the normal side. We also assess the location of movement relative to the oral commissure, that is to say the site of pull at the oral commissure (Fig. 11). We try very hard to replicate the normal side as best possible. After our preoperative planning is complete, we use an open approach through a preauricular incision and a submandibular extension on the involved paralyzed side. We carry the dissection medially towards the oral commissure at the level of the deep fat. We identify the area around the mouth and upper lip, sometimes with the aid of traction intraorally. We place our anchoring sutures very carefully into the oral commissure and upper lip. If there is excessive droop, we place an additional suture into the lower lip as well so that we can elevate the lower lip to its normal position relative to the normal side. Typically, we will place one suture in the oral commissure and two in the upper lip, and possibly one in the lower lip. With traction on these sutures, we assess the movement that is created and the future location of the pull of our muscle transplant (Fig. 12). This is one of the most important parts of the procedure, to get our anchoring sutures in exactly the right location. We also identify the facial artery and facial vein as these will be used to revascularize our muscle transplant. To minimize bulk, we remove the buccal fat pad as well as a portion of the deep fat that would lie directly on top of the muscle.
Figure 10 Sural nerve graft in place and ends placed on green background, ready for coaptation to facial nerve on normal side and secured to periosteum in upper buccal sulcus on involved side.
Figure 11 Preoperative planning prior to muscle transplant procedure noting vector, point of pull and facial artery.
Muscle tension In order to get the correct tension, we measure the distance from the oral commissure to the root of the helix, as this will be the length of our functioning muscle. We add 1 cm on each end for suturing and this will be the length of muscle that is procured from the thigh. Attention is then turned to the
Figure 12 Assessment of predicted excursion with traction on anchoring sutures.
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R.M. Zuker sutures. Once the muscle is secured, then the anchoring sutures are tied down and the muscle transplant is locked in place. Typically, we use a No. 1 Vicryl suture for our anchoring sutures. The muscle is then revascularized through microvascular anastomoses to the facial artery and vein. The motor nerve to gracilis is tunneled into the upper lip so that it lies next to our previously placed cross face nerve graft. An upper buccal sulcus incision is used to access the cross face nerve graft and prepare it for coaptation to the motor nerve to gracilis. This nerve repair is done under high magnification under the operating microscope intraorally.
Securing the muscle
In order to secure the muscle appropriately into the commissure and upper lip, we have a line of mattress sutures going across the end of the muscle that will be inserted into the commissure and upper lip. This line of mattress sutures will lock our anchoring sutures so that they will not slide through the muscle (Fig. 14). If we have four anchoring sutures, we utilize five mattress sutures. The anchoring suture goes into the muscle behind the mattress suture and then back into the oral commissure or upper lip very close to where the original one was. It then comes back through the muscle proximal to the next mattress suture just above the first. These are done sequentially so that the anchoring sutures are all locked behind this row of mattress
Now that the muscle is positioned into the oral commissure and upper lip, revascularized and reinnervated, we then secure the proximal portion to the temporal fascia. We do this with heavy vicryl mattress sutures, placing the muscle under the appropriate tension. This generally puts the oral commissure even with the normal side and with only slight tension (Fig. 15). It is not overcorrected as this will distort the mouth, nor is it undercorrected, as it will not provide for the appropriate excursion. After this, the cheek flap is repositioned and closed. We typically use a small Penrose drain, exiting from a post auricular separate stab incision. The drain lies close to the vascular anastomosis, but not adherent to it. After the cross face nerve graft muscle transplant combination procedures, we typically see muscle activity beginning at about 4 months post-muscle transplant. We then have the patient enter into an exercise program with biofeedback. They try to smile in front of a mirror and observe the activity of the reconstructed oral commissure. They try to increase the excursion so that it is as close to normal as possible, and also try to get it to become as spontaneous as possible. As we are utilizing the 7th nerve, spontaneity is generally not a problem and the muscle is activated at the same time as the normal side. Under close scrutiny, one can see a slight time delay as the neural activity moves across the cross face nerve graft from the normal side and into the muscle on the reconstructed side.
Figure 14 Gracilis being inserted with anchoring sutures locking behind row of mattress sutures.
Figure 15 Muscle transplant in place, revascularized and ready for securing sutures in temporal fascia under appropriate tension.
Figure 13 Segmental gracilis muscle procurement. Approximately, one third of circumference of muscle utilized.
thigh. An upper inner thigh incision is made and the gracilis muscle is encountered. Approximately one third of the circumference of the gracilis muscle is utilized with the neurovascular bundle at the center of our procurement (Fig. 13).
Muscle locking
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We have been very pleased with the results of this combination surgery (Fig. 16A—D). It is imperative, however, to use a significant amount of facial nerve on the normal side in order to provide adequate motor input. It is also important to only use a small segment of gracilis in order to avoid excess bulk. The results of unilateral facial paralysis reconstruction utilizing cross face nerve graft and muscle transplant combination surgeries can be seen in the following images.
We have tried various motor nerves, such as the hypoglossal, the accessory, but feel that the motor nerve to masseter is by far the best. It is a powerful nerve that will provide excellent excursion to the muscle transplant. We feel it also is in a better position to allow for spontaneity through cortical plasticity [7]. The muscle transplant procedure is essentially the same as that previously described. A pre-auricular incision with a submandibular extension is made. The dissection proceeds anteriorly toward the oral commissure. The plane is at the lower level of the deep fat. There is often no facial musculature to guide one in the plane of dissection. This is the case in Moebius syndrome, where no muscle has developed. In this situation, it is helpful to use the plane of the facial artery to guide the dissection. This will lead the operator in the correct plane without going too deep into the mucosa or too superficial into the dermis. We continue the dissection at the level of the facial artery to the oral commissure and upper lip. Here again, we place our anchoring sutures into
Muscle transplant innervated by the motor nerve to masseter In bilateral facial paralysis, there is no facial nerve available, and consequently, the cross face nerve graft procedure is not possible. In these situations, we have still found the segmental gracilis muscle transplant to be most useful. However, it needs to be innervated by a different motor nerve.
Figure 16 smiling.
Unilateral facial paralysis. A. Preoperative: at rest. B. Preoperative: smiling. C. Postoperative: at rest. D. Postoperative:
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the oral commissure and upper lip and do our measurements. The facial artery and vein are appropriately prepared.
The motor nerve to masseter The motor nerve to masseter is found by carrying the dissection deep through the masseter muscle to almost its under surface. It lies in the plane between the middle component and the deep component of the musculature. We utilize the Borschel rule to find the motor nerve to masseter. This is 3 cm anterior to the tragus and 1 cm inferior and deep to the mid component of the three lobes of the masseter muscle (Fig. 17) [8]. The nerve is identified as a white structure coursing downward and anteriorly toward the oral commissure. It is confirmed by the use of the electrostimulator. It is dissected into the musculature, divided at its point of branching and then brought upward to the surface of the muscle. Thus, it is in a better position for nerve coaptation to the motor nerve to gracilis. We find it helpful to remove the buccal fat pad. This aids in the dissection of the facial vessels and also reduces bulk in the cheek. We remove not only the buccal fat pad but also a small amount of the deep fat that will lie on top of the actual muscle transplant. The muscle is positioned as previously described and the vascular anastomoses are carried out. Then, the motor nerve to masseter is coapted to the motor nerve of the gracilis. The muscle is repositioned and secured in the temporal fascia, as previously described under appropriate tension (Fig. 18). Again, a small Penrose drain is utilized through a separate post-auricular stab incision. In bilateral cases, we do one side at a time and space them at least 3 months apart. We do this to allow the first side to become active so that we can see exactly the vector of pull and the location of the insertion. Thus, we are able to replicate this as best possible when we do the second side. We wait at least 3 months before doing the second side in bilateral cases to assess movement but could potentially wait longer depending on the wishes of the patient.
Reinnervation schedule After about 10 weeks, the muscle is reinnervated when the motor nerve to masseter is used. We again institute a
Figure 17
Finding the motor nerve to masseter.
rehabilitation program with smiling and biofeedback. Here, the biofeedback is extremely important in order to not only gain adequate excursion but also to create a degree of spontaneity. With ongoing therapy in the well-motivated patient, many do go on to have a spontaneous smile (Fig. 19A—E). However, this does not happen automatically but only with a frequent exercise program utilizing biofeedback. When the motor nerve to masseter is utilized, initially the patients have to bite down to activate the muscle. This is phase I and it occurs at about 10 to 12 weeks after surgery. Very quickly however, they move on to phase 2 where they are able to activate the muscle without moving the jaw. Then, with the rehab described and the biofeedback, they sometimes progress onto phase 3 where the activity becomes spontaneous when a smile is needed.
Discussion Muscle transplantation for facial paralysis is a very technically dependent procedure. It must be carried out precisely and each step is critical for its success. We feel the key elements are positioning the muscle appropriately and maintaining it in that location. This involves very careful suture placement and the technique described to limit any pulling through of the suture. The second critical factor is to reduce bulk. We do this by only using a small segment of the gracilis muscle, approximately 1/3 of the circumference. We also remove the buccal fat pad and some of the subcutaneous fat that will lie over the muscle. The third component is to provide a strong motor input. We do this by selecting a significant portion of the facial nerve on the normal side to coapt to a thin sural nerve graft. We try to get as much axon density into the nerve graft as possible. We utilize the motor nerve to masseter in bilateral cases, which provides enough power for normal muscle excursion. The fourth key to success is to provide appropriate tension on the muscle. This involves placing the muscle under a slight degree of tension so that the commissure just barely moves. With these four critical components, we have been very impressed with the results of muscle transplantation for facial paralysis reconstruction. We do rely on cortical plasticity when the motor nerve to masseter is utilized, fortunately in many cases that
Figure 18 Segmental gracilis muscle in position, revascularized and reinnervated by the motor nerve to masseter.
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Figure 19 Bilateral facial paralysis (Moebius syndrome). A. Preoperative: at rest. B. Preoperative: attempting a smile. C. Postoperative: at rest. D. Postoperative: small smile. E. Postoperative: full smile.
transference and spontaneity has occurred. However, there have been some where this spontaneity has not occurred and the required smile has to be thought about to happen. The reasons for this are under further investigation [9]. We believe that the motor nerve to masseter is an excellent choice in bilateral cases of facial paralysis. It is also appropriate when we would anticipate inadequate excursion because of a very powerful smile on the normal side. We also feel it is helpful in a failed previous procedure, where one does not want to dissect once again the normal facial nerve. In children with unilateral facial paralysis that is of the congenital type, our preference is still the cross face nerve graft/muscle transplant combination. In conclusion then, facial paralysis can have significant effects from a functional, psychological and aesthetic viewpoint. Reconstruction is possible. We feel that muscle transplantation can yield excellent results providing natural appearing oral commissure movement and excursion. The muscle can be powered either by a cross face nerve graft in unilateral cases, or by the motor nerve to masseter in bilateral cases. This surgical intervention can lead to
improved oral continence, clearer speech, improved facial symmetry and perhaps, most important, a restored smile in acquired cases and a created smile in congenital cases.
Disclosure of interest The author declares that he has no conflicts of interest concerning this article.
References [1] Westin LM, Zuker RM. A new classification system for facial paralysis in the clinical setting. J Craniofac Surg 2003;14:672. [2] Labbe D, Huault M. Lengthening temporalis myoplasty and lip reanimation. Plast Reconstr Surg 2000;105:1289. [3] Labbe D. Myoplastic d’allongement du temporal V.2 et réanimation des lèvres. Ann Chir Plast Esthet 2009;54:571. [4] 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 masseter. Plast Reconstr Surg 2006;117:2407.
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10 [5] Zuker RM, Gur E, Hussain G, Manktelow RT. Facial paralysis. Plast Surg 2013;3:278. [6] Manktelow RT, Zuker RM. Cross-facial nerve graft — The long and short graft: the first stage for microneurovascular muscle transfer. Oper Tech Plast Reconstr Surg 1999;6(3)174—9. [7] Zuker RM, Goldberg CS, Manktelow RT. Facial animation in children with moebius syndrome after segmental gracilis muscle transplant. Plast Reconstr Surg 2000;106:1.
R.M. Zuker [8] Borschel G, Zuker RM, Kawamura DH, Kasukurthi R, Hunter DA, Woo AS. The motor nerve to the masseter muscle: anatomic and histomorphometric study to facilitate its use in facial reanimation. Plast Reconstr Aesthet Surg 2012;363—6. [9] 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.
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