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Smile reconstruction using the serratus anterior muscle
SMILE RECONSTRUCTION USING THE SERRATUS ANTERIOR MUSCLE SCOTT P. BARTLETT, MD
In the rehabilitation of established facial palsy, cross-facial nerv e grafting followed by free-muscle transfer is the preferred method to restore facial balance and smile. At our institution we have used the serratus anterior muscle almost exclusively in these procedures. Advantages of this muscle include its ease of harvest, favorable muscular anatomy, consistent and lengthy neurovascular pediclG and minimal donor site morbidity. Copyright9 i:999by W.B. Saunders Company KEY WORDS: serratus muscle harvest, transfer, insetting, postoperative rehabilitation
With the development and refinement of microsurgical techniques, a new era was entered in the treatment of facial palsy. Previously limited to local static or dynamic slings, management has now been extended to include crossfacial nerve grafting and free-muscle transfer performed either in stages or conjointly. These techniques, b y offering volitional control of facial motion; represent the gold. standard of care for the patient with facial palsy. With minor variationsi cross-facial nerve grafting: techniques employed by most experts in the field of facial reanimation are similar. 1,2 There has evolved, however, differences of opinion regarding the optimal muscle to use in the second-stage reconstruction. Although t h e use of a variety of different muscles has been attempted, only four, the gracilis, 3 pectoralis minor, 4,s serratus anterior, 6,7 and latissimus dorsi s,9 are used regularly. At our institution we have used the serratus anterior almost exclusively. This experience has evolved over a 13-year interval during which, through trial and error, we have refined the technique for the use of this muscle. 7 The purpose of this report is to provide the operating surgeon with a step-by-step guide to the use of this muscle to rehabilitate the paralyzed face.
ANATOMY OF THE SERRATUS ANTERIOR MUSCLE The serratus anterior muscle forms a thin sheet between the chest wall and the scapula (Fig 1A). The muscle originates from a series of fleshy interdigitati0ns, covering ribs 1 through 8 or 9 and the intervening aponeuroses of the intercostal muscles. From these origins, it runs posteriorly and dorsally toward its insertion along the vertebral border of the scapula. 1~ Although the purpose of this muscle is to aid in scapular rotation during shoulder
From the University of Pennsylvania Medical Center and the Children's Hospital of Philadelphia, Philadelphia, PA. Address reprint requests to Scott P. Bartlett, MD, 10 Penn Tower, 3400 Spruce St, Philadelphia, PA 19104. Copyright 9 1999 by W;B. Saunders Company 1071-0949/99/0603-0008510.00/0
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motion, removal of several of the lower slips does not appear to affect overall shoulder function. The blood supply to the serratus anterior muscle is the thoracodorsal pedicle, which has been well described elsewhere, u After bifurcation of the subscapular artery and vein into the thoracod0rsal and CircumfleX vessels, the thoracodorsal vessels course downward to the latissimus dorsi muscle. These vessels consistently give off a major branch that supplies the inferior serratus muscle (Fig 1A). Thus, when this branch, along with several inferior slips of the muscle and the main thoracodorsal vessels are harvested, a consistent pedicle of 6 to 15 cm in length can be taken. AlthOugh unusual vascular variations have been described, we have not,encountered these clinically. Distinct from the vascular pedicle is the nerve supply to the serratus anterior muscle. The long thoracic nerve runs anteromedial to the vessels, intercepting and passing deep to the artery near the 5th rib (Fig 1A). This nerve pedicle ranges in length from 3 to 8 cm. 11Importantly, as this nerve passes over the first 3 or 4 slips, it gives off distinct branches to these slips. This allows one to split these fascicles off the main trunk and sacrifice only nerve that is supplying the distal musculature, 7 which will be harvested as 2, 3, or more slips en bloc (Fig 1B). The muscle itself is of the bipennate type with the fibers arranged obliquely.
STAGE ONE: CROSS-FACIAL NERVE GRAFT PLACEMENT Although placement of the cross-facial nerve graft as the first stage in microvascular muscle transfer has been described elsewhere in this issue, a few points are worthy of note. In certain patients, overactivity of lip depressors on the nonparalyzed side is seen. This leads to increased smile imbalance, even when a free-muscle transfer has achieved successful midface elevation. Accordingly, in these patients in w h o m this activity is strongest, direct deanimation of lip depressor activity is of value. 12 In the author's experience, techniques that attempt to reanimate lip depressors have been inconsistent and unreliable, hence, it is now common
Operative Techniques in Plastic and Reconstructive Surger)4, Vol 6, No 3 (August), 1999: pp 190-196
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Fig 1. (A) Anatomy of the serratus anterior muscle and its neurovascular pedicle; Note parallel arranged Slips and generous pediCle length, easily accessed through a midmaxiilary incision. (B) Muscle eievated on neurovaScuiar pedicle before trartsfer
practice during the first-stage, that of cross-facial nerve grafting, to deanimate the nonparalyzed lip depressors. Access to the facial nerve is obtained through an extended face-lift type of incision (Fig 2), which allows one to not only isolate the midbuccal branches to be used as donor nerves for the cross-facial nerve graft, but also to identify the cervical and marginal mandibular branches as
Fig 2, Extended face-lift type of incision used for midfacial access in both stage one and two, Note marking of lip depressor muscle vectors, USE OF THE SERRATUS ANTERIOR
they exit the parotid gland and course over the surface Of the masseter muscle inferiorly irito the neck. When seen here, each fiber can be individually stimulated with a nerve Stimulator, and those that cause lip depression can be sectioned (Fig 3A-B). Frequently, this will require removal of 1, 2, or 3 branches, because not only does direct lip-depressor muscle activity need to be ablated, but platysma activity as well (Fig 4A-B). The second point regarding this first-stage reanimation dealS with nerve-graft placement. Although the shortest distance between the nonparalyzed and paralyzed side of the face is across the upper lip, we have abandoned this in favor of submental nerve-graft placement (Fig 5). The reasons for this are twofold. First, placement of the nerve graft across the upper lip and onto the preauricular region puts it in a position to be easily injured during dissection or insetting of the free-muscle transfer. Even if it is identified in this position and shifted from harms way, a large portion of the terminal nerve will need to be separated from its surrounding vasculature, which may adversely effect nervegraft function. Second, in stage two of the operation, to be described in the section that follows, microvascular anastomoses are done to the anterior facial artery and vein; placing the nerve graft in the submental position ideally situates it for microscopic repair. A final point should be made regarding the selection of the buccal branch to be used (sacrificed). In my experience, the midbuccal region is served not only directly but by a great deal of crossover innervation from branches coursing to the face above and below this point. I routinely select the largest, most active, (when stimulated) midbuccal branch for the single-cross facial-nerve repair. In no instance has there been significant deanimation of the nonparalyzed side. In fact, partial deanimation of this nonparalyzed side during stage one frequently leads to improved facial balance both initially and after the completion of the free-muscle transfer.
191
Fig 3. (A-B) Isolation, identification, and section of nerves to lip depressor on nonparalyzed side as described in text. STAGE TWO: MICROVASCULAR OF THE SERRATUS ANTERIOR
TRANSFER MUSCLE
Once it has been determined that nerve-graft regeneration transfacially is complete, which usually take 9 to 12 months, stage two is undertaken. Before anesthetizing the patient, complete facial analysis and marking must be undertaken. With the patient sitting upright and relaxed, the best vector of midfacial lift on the nonparalyzed side is marked. A mirror image marking of
this is then transferred to the opposite side. Also marked is the position of the nasolabial fold~on the nonparalyzed side. This position is also transferred to the contralateral side, but placed more medially than expected, because when the muscle is inset this will frequently be pulled to a more lateral position (Fig 6). Once this vector analysis has been completed, the operation can commence. One of the advantages of the use of the serratus anterior muscle is the ease of harvest, which can be combined with
Fig 4. (A) Overactive lip depressors seen preoperatively. (B) After Stage one, cross-facial nerve graft, and resection of lip depressor nerves, improved balance of the lower lip is seen.
192
SCOTT P. BARTLETT
match the contralateral side when the muscle is inset and functioning (Fig 8). Early in the author's experience, a nasolabial fold incision was used for muscle inset, combining this with a de-epithelialized buried strip at the nasolabial fold. With the technique described previously, this extra incision is not necessary and, therefore, no scars are left in the central face. Simultaneous with recipient site preparation is the harvest of the serratus anterior muscle. The muscle is approached through a midaxillary incision. After elevation and reflection of the subcutaneous tissues, the edge of the latissimus dorsi muscle is identified and, with that, the thoracodorsal pedicle and the subjacent serratus anterior muscle. After identifying the muscular slips of the serratus, one can move proximally, identifying both the nerve and artery to the muscle. Dissection is performed into the axilla, dividing the main trunk of;the thoracodorsal to the latissimus dorsi muscle to maintain the length of the pedicle to the serratus muscle. Similarly, the long thoracic nerve is identified and dissected anteriorly and superiorly. As mentioned previously, the nerve frequently has distinct fascicles to the upper 2 or 3 slips that can be separated from the remainder of the nerve. 7 At this point, the slips of the serratus to be used are identified, typically 3, or'at the most 4, in number. These are separated from slips above and below, and are dissected sharply and bluntly from both the ribs anteriorly and the scapula posteriorly. The muscle can then be raised as a true island pedicle based on the nerves Fig 5. Course of submental nerve graft placement.
the preparation of the recipient site by two teams working simultaneously. The recipient site is approached by making a mirror image-extended face-lift incision on the paralyzed side of the face and elevating a skin flap well into the cheek. The terminal end of the cross-facial nerve graft is identified and this is gently dissected inferiorly in the cheek to the level of the facial vessels. The extent of the dissection is determined by the preoperative markings of vectors. Typically, the skin is elevated in a deep subcutaneous plane well out across the nasolabial fold region to the upper lip, commissure, and lower lip. Additional dissection may be performed into the alar base if a muscle slip is to be positioned here to aid in both dynamic and static nostril opening. Once this pocket is dissected, attention is directed to isolation of the anterior facial artery and vein as they course over the mandibular border. This is performed under loupe magnification with each vessel being dissected free from the surrounding tissue for approximately 2 cm (Fig 7). Because the inset of the muscle will depend on the direction of the vector pull, at this point of the operation stitches for distal inset of the muscle are placed. Based on the patient's contralateral anatomy, three or four sutures are used. The two main sutures are those at the modiolus and the lateral upper lip, with supplemental sutures placed at the alar base and lower lip, as determined by vector analysis. The stitches themselves are typically permanent 2-0 or 3-0 braided suture, which encompass all tissue between skin and mucosa and do not include dermis. After placement of each stitch, gentle traction determines if indeed they are positioned appropriately to
USE OF THE SERRATUS ANTERIOR
Fig 6. Preoperative vector markings. Patients left side is normal. The mirror image right-side markings are made with the placement of the nasolabial fold more medially as described in text.
193
Fig 7. Preparation of the recipient site (right face) with isolation of anterior facial vessels (single arrOw) and crossfacial nerve graft (double arrow).
and vessels. After heparinization, the nutrient vessels to the flap are divided and the muscle is removed. it is most useful to transfer the muscle =r the face by turning it over, such that the superficial surface is deep. If a generous amount of muscle has been taken, one can then tailor the muscle in the face either proximally or distally to ensure that the pedicle of the muscle matches the facial vessels at the recipient site (Fig 9). The first thing one does is to gently stretch the muscle out on the face to a moderate degree of tension and trim proximally and distally. By doing this, one assures that the pedicle will align properly. The muscle is then inset into the nas olabial fold (upper lip, alar base, modiolus, lower lip) by using the previously placed sutures in a mattress fashion to the muscle. These are tied down sequentially as the muscle is inset against the nasolabiat fold region. The muscle is then put on stretch for proximal fixation. Although no absolute guide can be outlined for determining the amount of tension to place on a muscle, it is has been m y experience that near maximal tension is required. This will result in an overcorrected nasolabial fold position, which will relax over the next 3 to 6 weeks (Fig 10A-B). If the muscle tends to distort and roll on itself, it is best to incise the muscular fascia to allow it to drape more evenly. The muscle is generally trimmed on a bias proximally so that it may be affixed superiorly. Fixation is usually performed to the zygomatic arch periosteom and the superficial layer of the deep temporal fascia, again with braided 2-0 or 3-0 mattress sutures. At this point, microneurovascular repairs are
194
Fig 8. After placement of sutures at modiolus and the upper and lower lips, traction confirms satisfactory position.
made. If the trimming and insetting of the muscle were performed appropriately, then donor and recipient nerve, artery, and vein are now in close proximity. Repair of the artery and vein is typically done in an end-to-end fashion, because this gives the best size match and provides for the best and most unambiguous monitoring postoperatively. The nerve repair should be done with the least amount of tension, but also with the elimination of any redundant donor or recipient nerve, so that reinnervation of muscle occurs promptly.
Fig 9. Trimming of serratus muscle before inset and microneurovascular repair.
SCOTT P. BARTLETT
Fig 10. (A-B) After muscle inset and closure. Note degree of overcorrection of "smile," AFTERCARE
The patient remains in the hospital for approximately 5 days of monitoring. Aspirin is given daily per rectum and no other anticoagulants are Used unless difficulty was encountered with the anastomoses. Patients are advised to continue aspirin for 3 to 6 months. The patient is assessed every several weeks. If the operation has been successful, muscular activity begins in 3 to 6 months, and at this point the patient is instructed in exercises to maximize motion. Alternativel~ this can be clOne with the aid of a therapist. Over the past I3 years, the author has completed 29 cases of which approximately 24 are available for complete follow-up review. There have been no microvascular failures and approximately 75% to 80% of the patients' results
have been judged good to excellent. Clinical examples are shown in Figs 11A-B and 12A-B.
CONCLUSION
Based on our experience with the serratus anterior muscle, we feel that it is an ideal muscle for use in reanimation of the paralyzed face. There is almost no donor-site morbidity and the donor scar is well concealed. The muscle has a consistent and lengthy neurovaScular pedicle and the dissection, for the most part, can easily be mastered by a senior resident in training. This long neurovascular pedicle, combined with placement of the nerve graft, submentally makes anastomosis to the anterior facial vessels possible in virtually all cases. These vessels are typically larger than
Fig 11. Patient smiling before (A) and after (B) muscle transfer.
USE OF THE SERRATUS ANTERIOR
195
Fig 12. Patient smiling before (A) and after (B) muscle transfer.
the t e m p o r a l vessels a n d , therefore, m o r e reliable. A d d i t i o n ally, the m u l t i p l e slips of the m u s c l e m a k e for a c c u r a t e i n s e t i n a n d a r o u n d the lip a n d m o d i o l u s , a n d the b u l k a n d size of the m u s c l e are i d e a l u n d e r m o s t c i r c u m s t a n c e s . A p o t e n t i a l d i s a d v a n t a g e of the flap is the m u s c u l a r a n a t o m y . Because the fibers are b i p e n n a t e a n d , therefore, oblique in their orientation, one could theoretically argue t h a t e x c u r s i o n of the m u s c l e w o u l d n o t b e as g r e a t as t h o s e i n w h i c h the m u s c l e fibers are all o r i e n t e d l o n g i t u d i n a l l y a n d parallel. We h a v e n o t s e e n this to b e the case.
REFERENCES 1. Anderl H: Cross-facial nerve transplant. Clin Plast Surg 6:433-443, 1979 2. WellsMD, Manktelow RT: Surgical management of facial palsy. Clin Plast Surg 17:645-656, 1990 3. Harri K, Ohmori K, Torii S: Free gracilis muscle transplantation with microneurovascular anastomosis for the treatment of facial paralysis. Plast Reconstr Surg 57:133-141,1976 4. HarrisOn D: The pectoralis minor vascularized muscle graft for tl~e treatment of unilateral facialpalsy. Plast ReconstrSurg 75:206-213,1985
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5. Terzis JK: Pectoralis minor: A unique muscle for correction of facial palsy. Plast Reconstr Surg 83:767-773, 1989 6. Buncke HJ, Alpert BS, Gordon L, et al: Free serratus anterior muscle transplantation for unilateral facial nerve paralysis. Presented at the American Association of Plastic Surgeons Annual Meeting, May 21-24, 1984, Chicago, IL 7. Bartlett SP, Reedy BK: Technical refinements in the use of the serratus anterior to reanimate the paralyzed face. Presented at the American Association of Plastic Surgeons Annual Meeting, May 17-20, 1998, Montreal, Quebec, Canada 8. Harii K, Asato H, Yoshimura K, et ah One-stage transfer of the latissimus dorsi muscle for reanimation of the paralyzed face: A new alternative. Plast Reconstr Surg 102:941-949,1998 9. Wei W, Zuoliang Q, Xiaoxi L, et al: Free split and segmental latissimus dorsi muscle transfer in one stage for facial reanimation. Plast Reconstr Surg 103:473-480,1999 10. Derby LD, Bartlett SP, Low DW: Serratus anterior free tissue transfer: Harvest related morbidity in 34 consecutive cases and a review of the literature. J Reconstr Microsurg 13:397-403,1997 11. Bartlett SP, May JW, Yaremchuk MJ: The latissimus dorsi musclei A fresh cadaver study of the primary neurovascular pedicle. Plast Reconstr Surg 67:631-636,1981 12. Conley J, Baker DC, Selfe RW: Paralysis of the mandibular branch of the facial nerve. Plast Reconstr Surg 78:569-573,1982
SCOTT P. BARTLETT
In the rehabilitation of established facial palsy, cross-facial nerv e grafting followed by free-muscle transfer is the preferred method to restore facial balance and smile. At our institution we have used the serratus anterior muscle almost exclusively in these procedures. Advantages of this muscle include its ease of harvest, favorable muscular anatomy, consistent and lengthy neurovascular pediclG and minimal donor site morbidity. Copyright9 i:999by W.B. Saunders Company KEY WORDS: serratus muscle harvest, transfer, insetting, postoperative rehabilitation
With the development and refinement of microsurgical techniques, a new era was entered in the treatment of facial palsy. Previously limited to local static or dynamic slings, management has now been extended to include crossfacial nerve grafting and free-muscle transfer performed either in stages or conjointly. These techniques, b y offering volitional control of facial motion; represent the gold. standard of care for the patient with facial palsy. With minor variationsi cross-facial nerve grafting: techniques employed by most experts in the field of facial reanimation are similar. 1,2 There has evolved, however, differences of opinion regarding the optimal muscle to use in the second-stage reconstruction. Although t h e use of a variety of different muscles has been attempted, only four, the gracilis, 3 pectoralis minor, 4,s serratus anterior, 6,7 and latissimus dorsi s,9 are used regularly. At our institution we have used the serratus anterior almost exclusively. This experience has evolved over a 13-year interval during which, through trial and error, we have refined the technique for the use of this muscle. 7 The purpose of this report is to provide the operating surgeon with a step-by-step guide to the use of this muscle to rehabilitate the paralyzed face.
ANATOMY OF THE SERRATUS ANTERIOR MUSCLE The serratus anterior muscle forms a thin sheet between the chest wall and the scapula (Fig 1A). The muscle originates from a series of fleshy interdigitati0ns, covering ribs 1 through 8 or 9 and the intervening aponeuroses of the intercostal muscles. From these origins, it runs posteriorly and dorsally toward its insertion along the vertebral border of the scapula. 1~ Although the purpose of this muscle is to aid in scapular rotation during shoulder
From the University of Pennsylvania Medical Center and the Children's Hospital of Philadelphia, Philadelphia, PA. Address reprint requests to Scott P. Bartlett, MD, 10 Penn Tower, 3400 Spruce St, Philadelphia, PA 19104. Copyright 9 1999 by W;B. Saunders Company 1071-0949/99/0603-0008510.00/0
190
motion, removal of several of the lower slips does not appear to affect overall shoulder function. The blood supply to the serratus anterior muscle is the thoracodorsal pedicle, which has been well described elsewhere, u After bifurcation of the subscapular artery and vein into the thoracod0rsal and CircumfleX vessels, the thoracodorsal vessels course downward to the latissimus dorsi muscle. These vessels consistently give off a major branch that supplies the inferior serratus muscle (Fig 1A). Thus, when this branch, along with several inferior slips of the muscle and the main thoracodorsal vessels are harvested, a consistent pedicle of 6 to 15 cm in length can be taken. AlthOugh unusual vascular variations have been described, we have not,encountered these clinically. Distinct from the vascular pedicle is the nerve supply to the serratus anterior muscle. The long thoracic nerve runs anteromedial to the vessels, intercepting and passing deep to the artery near the 5th rib (Fig 1A). This nerve pedicle ranges in length from 3 to 8 cm. 11Importantly, as this nerve passes over the first 3 or 4 slips, it gives off distinct branches to these slips. This allows one to split these fascicles off the main trunk and sacrifice only nerve that is supplying the distal musculature, 7 which will be harvested as 2, 3, or more slips en bloc (Fig 1B). The muscle itself is of the bipennate type with the fibers arranged obliquely.
STAGE ONE: CROSS-FACIAL NERVE GRAFT PLACEMENT Although placement of the cross-facial nerve graft as the first stage in microvascular muscle transfer has been described elsewhere in this issue, a few points are worthy of note. In certain patients, overactivity of lip depressors on the nonparalyzed side is seen. This leads to increased smile imbalance, even when a free-muscle transfer has achieved successful midface elevation. Accordingly, in these patients in w h o m this activity is strongest, direct deanimation of lip depressor activity is of value. 12 In the author's experience, techniques that attempt to reanimate lip depressors have been inconsistent and unreliable, hence, it is now common
Operative Techniques in Plastic and Reconstructive Surger)4, Vol 6, No 3 (August), 1999: pp 190-196
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B
j -/ ~r
Fig 1. (A) Anatomy of the serratus anterior muscle and its neurovascular pedicle; Note parallel arranged Slips and generous pediCle length, easily accessed through a midmaxiilary incision. (B) Muscle eievated on neurovaScuiar pedicle before trartsfer
practice during the first-stage, that of cross-facial nerve grafting, to deanimate the nonparalyzed lip depressors. Access to the facial nerve is obtained through an extended face-lift type of incision (Fig 2), which allows one to not only isolate the midbuccal branches to be used as donor nerves for the cross-facial nerve graft, but also to identify the cervical and marginal mandibular branches as
Fig 2, Extended face-lift type of incision used for midfacial access in both stage one and two, Note marking of lip depressor muscle vectors, USE OF THE SERRATUS ANTERIOR
they exit the parotid gland and course over the surface Of the masseter muscle inferiorly irito the neck. When seen here, each fiber can be individually stimulated with a nerve Stimulator, and those that cause lip depression can be sectioned (Fig 3A-B). Frequently, this will require removal of 1, 2, or 3 branches, because not only does direct lip-depressor muscle activity need to be ablated, but platysma activity as well (Fig 4A-B). The second point regarding this first-stage reanimation dealS with nerve-graft placement. Although the shortest distance between the nonparalyzed and paralyzed side of the face is across the upper lip, we have abandoned this in favor of submental nerve-graft placement (Fig 5). The reasons for this are twofold. First, placement of the nerve graft across the upper lip and onto the preauricular region puts it in a position to be easily injured during dissection or insetting of the free-muscle transfer. Even if it is identified in this position and shifted from harms way, a large portion of the terminal nerve will need to be separated from its surrounding vasculature, which may adversely effect nervegraft function. Second, in stage two of the operation, to be described in the section that follows, microvascular anastomoses are done to the anterior facial artery and vein; placing the nerve graft in the submental position ideally situates it for microscopic repair. A final point should be made regarding the selection of the buccal branch to be used (sacrificed). In my experience, the midbuccal region is served not only directly but by a great deal of crossover innervation from branches coursing to the face above and below this point. I routinely select the largest, most active, (when stimulated) midbuccal branch for the single-cross facial-nerve repair. In no instance has there been significant deanimation of the nonparalyzed side. In fact, partial deanimation of this nonparalyzed side during stage one frequently leads to improved facial balance both initially and after the completion of the free-muscle transfer.
191
Fig 3. (A-B) Isolation, identification, and section of nerves to lip depressor on nonparalyzed side as described in text. STAGE TWO: MICROVASCULAR OF THE SERRATUS ANTERIOR
TRANSFER MUSCLE
Once it has been determined that nerve-graft regeneration transfacially is complete, which usually take 9 to 12 months, stage two is undertaken. Before anesthetizing the patient, complete facial analysis and marking must be undertaken. With the patient sitting upright and relaxed, the best vector of midfacial lift on the nonparalyzed side is marked. A mirror image marking of
this is then transferred to the opposite side. Also marked is the position of the nasolabial fold~on the nonparalyzed side. This position is also transferred to the contralateral side, but placed more medially than expected, because when the muscle is inset this will frequently be pulled to a more lateral position (Fig 6). Once this vector analysis has been completed, the operation can commence. One of the advantages of the use of the serratus anterior muscle is the ease of harvest, which can be combined with
Fig 4. (A) Overactive lip depressors seen preoperatively. (B) After Stage one, cross-facial nerve graft, and resection of lip depressor nerves, improved balance of the lower lip is seen.
192
SCOTT P. BARTLETT
match the contralateral side when the muscle is inset and functioning (Fig 8). Early in the author's experience, a nasolabial fold incision was used for muscle inset, combining this with a de-epithelialized buried strip at the nasolabial fold. With the technique described previously, this extra incision is not necessary and, therefore, no scars are left in the central face. Simultaneous with recipient site preparation is the harvest of the serratus anterior muscle. The muscle is approached through a midaxillary incision. After elevation and reflection of the subcutaneous tissues, the edge of the latissimus dorsi muscle is identified and, with that, the thoracodorsal pedicle and the subjacent serratus anterior muscle. After identifying the muscular slips of the serratus, one can move proximally, identifying both the nerve and artery to the muscle. Dissection is performed into the axilla, dividing the main trunk of;the thoracodorsal to the latissimus dorsi muscle to maintain the length of the pedicle to the serratus muscle. Similarly, the long thoracic nerve is identified and dissected anteriorly and superiorly. As mentioned previously, the nerve frequently has distinct fascicles to the upper 2 or 3 slips that can be separated from the remainder of the nerve. 7 At this point, the slips of the serratus to be used are identified, typically 3, or'at the most 4, in number. These are separated from slips above and below, and are dissected sharply and bluntly from both the ribs anteriorly and the scapula posteriorly. The muscle can then be raised as a true island pedicle based on the nerves Fig 5. Course of submental nerve graft placement.
the preparation of the recipient site by two teams working simultaneously. The recipient site is approached by making a mirror image-extended face-lift incision on the paralyzed side of the face and elevating a skin flap well into the cheek. The terminal end of the cross-facial nerve graft is identified and this is gently dissected inferiorly in the cheek to the level of the facial vessels. The extent of the dissection is determined by the preoperative markings of vectors. Typically, the skin is elevated in a deep subcutaneous plane well out across the nasolabial fold region to the upper lip, commissure, and lower lip. Additional dissection may be performed into the alar base if a muscle slip is to be positioned here to aid in both dynamic and static nostril opening. Once this pocket is dissected, attention is directed to isolation of the anterior facial artery and vein as they course over the mandibular border. This is performed under loupe magnification with each vessel being dissected free from the surrounding tissue for approximately 2 cm (Fig 7). Because the inset of the muscle will depend on the direction of the vector pull, at this point of the operation stitches for distal inset of the muscle are placed. Based on the patient's contralateral anatomy, three or four sutures are used. The two main sutures are those at the modiolus and the lateral upper lip, with supplemental sutures placed at the alar base and lower lip, as determined by vector analysis. The stitches themselves are typically permanent 2-0 or 3-0 braided suture, which encompass all tissue between skin and mucosa and do not include dermis. After placement of each stitch, gentle traction determines if indeed they are positioned appropriately to
USE OF THE SERRATUS ANTERIOR
Fig 6. Preoperative vector markings. Patients left side is normal. The mirror image right-side markings are made with the placement of the nasolabial fold more medially as described in text.
193
Fig 7. Preparation of the recipient site (right face) with isolation of anterior facial vessels (single arrOw) and crossfacial nerve graft (double arrow).
and vessels. After heparinization, the nutrient vessels to the flap are divided and the muscle is removed. it is most useful to transfer the muscle =r the face by turning it over, such that the superficial surface is deep. If a generous amount of muscle has been taken, one can then tailor the muscle in the face either proximally or distally to ensure that the pedicle of the muscle matches the facial vessels at the recipient site (Fig 9). The first thing one does is to gently stretch the muscle out on the face to a moderate degree of tension and trim proximally and distally. By doing this, one assures that the pedicle will align properly. The muscle is then inset into the nas olabial fold (upper lip, alar base, modiolus, lower lip) by using the previously placed sutures in a mattress fashion to the muscle. These are tied down sequentially as the muscle is inset against the nasolabiat fold region. The muscle is then put on stretch for proximal fixation. Although no absolute guide can be outlined for determining the amount of tension to place on a muscle, it is has been m y experience that near maximal tension is required. This will result in an overcorrected nasolabial fold position, which will relax over the next 3 to 6 weeks (Fig 10A-B). If the muscle tends to distort and roll on itself, it is best to incise the muscular fascia to allow it to drape more evenly. The muscle is generally trimmed on a bias proximally so that it may be affixed superiorly. Fixation is usually performed to the zygomatic arch periosteom and the superficial layer of the deep temporal fascia, again with braided 2-0 or 3-0 mattress sutures. At this point, microneurovascular repairs are
194
Fig 8. After placement of sutures at modiolus and the upper and lower lips, traction confirms satisfactory position.
made. If the trimming and insetting of the muscle were performed appropriately, then donor and recipient nerve, artery, and vein are now in close proximity. Repair of the artery and vein is typically done in an end-to-end fashion, because this gives the best size match and provides for the best and most unambiguous monitoring postoperatively. The nerve repair should be done with the least amount of tension, but also with the elimination of any redundant donor or recipient nerve, so that reinnervation of muscle occurs promptly.
Fig 9. Trimming of serratus muscle before inset and microneurovascular repair.
SCOTT P. BARTLETT
Fig 10. (A-B) After muscle inset and closure. Note degree of overcorrection of "smile," AFTERCARE
The patient remains in the hospital for approximately 5 days of monitoring. Aspirin is given daily per rectum and no other anticoagulants are Used unless difficulty was encountered with the anastomoses. Patients are advised to continue aspirin for 3 to 6 months. The patient is assessed every several weeks. If the operation has been successful, muscular activity begins in 3 to 6 months, and at this point the patient is instructed in exercises to maximize motion. Alternativel~ this can be clOne with the aid of a therapist. Over the past I3 years, the author has completed 29 cases of which approximately 24 are available for complete follow-up review. There have been no microvascular failures and approximately 75% to 80% of the patients' results
have been judged good to excellent. Clinical examples are shown in Figs 11A-B and 12A-B.
CONCLUSION
Based on our experience with the serratus anterior muscle, we feel that it is an ideal muscle for use in reanimation of the paralyzed face. There is almost no donor-site morbidity and the donor scar is well concealed. The muscle has a consistent and lengthy neurovaScular pedicle and the dissection, for the most part, can easily be mastered by a senior resident in training. This long neurovascular pedicle, combined with placement of the nerve graft, submentally makes anastomosis to the anterior facial vessels possible in virtually all cases. These vessels are typically larger than
Fig 11. Patient smiling before (A) and after (B) muscle transfer.
USE OF THE SERRATUS ANTERIOR
195
Fig 12. Patient smiling before (A) and after (B) muscle transfer.
the t e m p o r a l vessels a n d , therefore, m o r e reliable. A d d i t i o n ally, the m u l t i p l e slips of the m u s c l e m a k e for a c c u r a t e i n s e t i n a n d a r o u n d the lip a n d m o d i o l u s , a n d the b u l k a n d size of the m u s c l e are i d e a l u n d e r m o s t c i r c u m s t a n c e s . A p o t e n t i a l d i s a d v a n t a g e of the flap is the m u s c u l a r a n a t o m y . Because the fibers are b i p e n n a t e a n d , therefore, oblique in their orientation, one could theoretically argue t h a t e x c u r s i o n of the m u s c l e w o u l d n o t b e as g r e a t as t h o s e i n w h i c h the m u s c l e fibers are all o r i e n t e d l o n g i t u d i n a l l y a n d parallel. We h a v e n o t s e e n this to b e the case.
REFERENCES 1. Anderl H: Cross-facial nerve transplant. Clin Plast Surg 6:433-443, 1979 2. WellsMD, Manktelow RT: Surgical management of facial palsy. Clin Plast Surg 17:645-656, 1990 3. Harri K, Ohmori K, Torii S: Free gracilis muscle transplantation with microneurovascular anastomosis for the treatment of facial paralysis. Plast Reconstr Surg 57:133-141,1976 4. HarrisOn D: The pectoralis minor vascularized muscle graft for tl~e treatment of unilateral facialpalsy. Plast ReconstrSurg 75:206-213,1985
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5. Terzis JK: Pectoralis minor: A unique muscle for correction of facial palsy. Plast Reconstr Surg 83:767-773, 1989 6. Buncke HJ, Alpert BS, Gordon L, et al: Free serratus anterior muscle transplantation for unilateral facial nerve paralysis. Presented at the American Association of Plastic Surgeons Annual Meeting, May 21-24, 1984, Chicago, IL 7. Bartlett SP, Reedy BK: Technical refinements in the use of the serratus anterior to reanimate the paralyzed face. Presented at the American Association of Plastic Surgeons Annual Meeting, May 17-20, 1998, Montreal, Quebec, Canada 8. Harii K, Asato H, Yoshimura K, et ah One-stage transfer of the latissimus dorsi muscle for reanimation of the paralyzed face: A new alternative. Plast Reconstr Surg 102:941-949,1998 9. Wei W, Zuoliang Q, Xiaoxi L, et al: Free split and segmental latissimus dorsi muscle transfer in one stage for facial reanimation. Plast Reconstr Surg 103:473-480,1999 10. Derby LD, Bartlett SP, Low DW: Serratus anterior free tissue transfer: Harvest related morbidity in 34 consecutive cases and a review of the literature. J Reconstr Microsurg 13:397-403,1997 11. Bartlett SP, May JW, Yaremchuk MJ: The latissimus dorsi musclei A fresh cadaver study of the primary neurovascular pedicle. Plast Reconstr Surg 67:631-636,1981 12. Conley J, Baker DC, Selfe RW: Paralysis of the mandibular branch of the facial nerve. Plast Reconstr Surg 78:569-573,1982
SCOTT P. BARTLETT