Douglas B. Chepeha
INTRODUCTION
To prepare for free flap reconstruction of the cheek, a history that involves discussion of the patient’s objectives will affect donor site choice. Depending on the patient’s body habitus and skin color, different sites will affect the degree that the skin paddle of the transplant will blend with the recipient site. I use the subscapular/thoracodorsal system or the lateral arm as donor sites. Careful assessment of prior surgery, past or future radiation planning, orbital function, ocular function, position of the corner of the mouth, facial nerve function, and depth of the planned defect is important. The cheek consists of three lamellae that, in total, are quite thin; the skin/ subcutaneous tissue, the superficial muscle aponeurotic system (SMAS), and the buccinator/buccal mucosa. It is important to address all three lamellae, be sure to maintain the suspension of the corner of the mouth, and support the lower eyelid (Figs. 36.1and 36.2). For tumors that involve more than one layer and/or perineural invasion is a concern, MRI and CT are an important component of preoperative assessment and planning. When assessing the patient for cheek reconstruction, it is important to consider local tissue. A free tissue transfer should be used for patients who have inadequate local donor tissue, have involvement of at least two lamellae of the cheek, will develop ectropion, or will not be able to maintain the position of the corner of the mouth.
FIGURE 36.1 This is a 62-year-old woman who has undergone resection of a maxillary sinus squamous cell carcinoma (SCC) that involved the cheek subunit. This is an intraoperative view of the left lateral face. The blue paper template has been made for the external skin paddle. Eight marks have been placed on the template for transfer to the donor site to facilitate the inset. The defect includes all three lamellae of the cheek. The angle of the mouth requires suspension of the modiolus. The nerve to the upper lip orbicularis oris was stimulated and was felt not to require additional nerve grafting.
FIGURE 36.2 This is an elevated thoracodorsal artery scapular tip flap (TDAST). Three paddles have been elevated from the donor site. The cheek portion of the skin paddle is shown on the lower left of the image, and the serratus muscle is shown on the upper right of the image. The cheek skin template has been outlined, and the remainder of the skin paddle will be deepithelialized. The additional skin paddle will be used to restore volume and resurface the posterior palate. The bone will be used to restore the malar eminence and orbital rim. The markings on the skin paddle can be seen; these will aid the inset at the recipient site.
HISTORY
As with any history, the assessment has to take into account prior treatment, the extent of the defect, and the patient’s goals relative to what the reconstructive intervention can accomplish. If the patient had a significant radiation or smoking history, the likelihood of a wound complication or late tissue atrophy increases. Therefore, a thicker, higher volume reconstruction may require customization of the flap or choice of an alternative donor site. Prior trauma or surgery to possible donor sites needs to be assessed. It is best to have a primary and secondary donor site discussed with the patient prior to the surgery. It is important to know about prior surgery or trauma to the site to understand the risk to the facial nerve, for example, prior local excision, parotid procedures, local flaps, facelift, facial trauma, or idiopathic facial nerve weakness. It is important to take a history about prior eye surgery or trauma, because this is an adjacent subunit and can be impacted by cheek reconstruction. It is important to support the lower eyelid with the reconstruction. If there is a preexisting ectropion, or the cheek defect extends to the eyelid subunit, an oculoplastics consultation should be considered.
PHYSICAL EXAMINATION
Assessment of the extent of the disease is essential for the surgeon to plan the defect, help prepare for tissue transplantation, and help to educate the patient. In the case of prior trauma, burns, or surgery, the degree of contracture of the involved subunits is important to assess to allow for compensation with skin paddle design. The goal of the assessment is to determine the extent and depth of the cheek subunit involvement. Specifically, assessment of the involvement of the adjacent eyelid and nasal subunits, the involvement of the deeper lamellae of the cheek that include the SMAS, the facial nerve, the buccinator muscle, the parotid duct, and the buccal mucosa. Bimanual palpation is helpful to assess the depth of tumor involvement. Intraoral examination of the buccal mucosa is good for assessing the extent of intraoral involvement. Palpation of the infraorbital rim is good for assessing lid mobility and deep extension. Observing the face in repose in addition to eye closure, angle of mouth elevation, and lip closure is useful to determine SMAS or facial nerve involvement. Testing of cheek sensation is useful for determining involvement of the infraorbital nerve.
INDICATIONS
Local flaps such as cervical facial rotation flaps are the reconstruction of first choice for cheek defects. Microsurgical reconstruction of cheek defects is for patients who have inadequate local donor tissue for a local rotational, advancement, or interpolation flaps. These situations arise when there has been extensive tissue loss such as in burns, trauma, or necrotizing fasciitis, in situations where the defect is deep and the essential elements of the SMAS, facial nerve, lower eyelid, and/or the buccal mucosa have been lost. The goals of cheek reconstruction are to prevent ectropion, maintain the position of the corner of the mouth, restore the soft tissue contour of the midface, prevent rotation and contracture of the nose into the reconstructed cheek, and maintain jaw opening by providing adequate intraoral lining.
CONTRAINDICATIONS
It is important to assess the local tissue options and not immediately move to a microsurgical option. There are few contraindications because patients tolerate cheek reconstruction well. As with any major surgical procedure, patients need adequate preoperative clearance.
PREOPERATIVE PLANNING
Radiology
The need for radiology varies greatly depending on the etiology of the defect, depth of the defect, and prior treatment. For superficial lesions, the need for preoperative imaging is limited. Imaging is important for patients with neoplastic disease extending to the SMAS, who have facial nerve weakness, who have had prior treatment, or whose disease crosses outside the cheek anatomic subunit, to anticipate the extent of the defect. CT scan with contrast is useful for assessment of the fascial planes of the SMAS, buccinator, pterygomandibular raphe, nasal facial groove, and the orbital septum. If there are facial nerve findings that are more extensive than the primary lesion would suggest, then an MRI can be helpful to assess perineural invasion. This would help anticipate the extent of nerve grafting that would be necessary. As with any reconstructive microsurgery case, the recipient artery and vein have to be a part of the reconstructive plan. If the patient had prior neck exploration or dissection, consideration of a CT angiogram to aid in identification of recipient artery can be helpful so that a donor site with adequate pedicle length can be chosen.
For cheek reconstruction, color and contour match are important when choosing the donor site. A patient’s body habitus and skin color will affect the choice of donor site. Also, when choosing the adipose tissue used for contouring, it should be from a site that will not become ptotic when inset into the recipient site. For many patients, the lateral arm and the parascapular/latissimus site provide the best color match, are good for contouring, have fewer problems with ptosis, and are my first choice sites. The lateral arm is also a good donor site for nerve grafts, particularly the posterior antebrachial cutaneous nerve (PACN) of the forearm. Despite these advantages, the lateral arm site has a very short, very small-caliber pedicle and will rarely reach past the facial or occipital artery recipient sites and, for this reason, is less commonly used. The parascapular/latissimus donor site has a longer, larger caliber pedicle, has well-compartmentalized adipose tissue, and good skin color match, but the harvest is from the lateral thorax, and this makes the elevation more difficult when the extirpation is being performed. To overcome this, I place the patient in a semidecubitus position for the extirpation and reconstruction.
The most commonly used donor site for cheek defect reconstruction is the anterolateral thigh (ALT) donor site because it has a long, large-caliber pedicle, is easy to harvest during the extirpation of the cheek, and is at least second best for many of the reconstructive challenges of cheek reconstruction. The color match of the ALT is not as good as that of the lateral arm or the parascapular site, but it offers a long pedicle that is particularly valuable for patients who have a “vessel poor” neck. If the ALT donor site is thin, volume issues are easily addressed by elevating a larger skin paddle that can be deepithelialized to obtain adequate volume. The vastus lateralis of the ALT donor site can be used to aid in the reconstruction of intraoral defects; otherwise this donor site is best elevated as a muscle sparing or perforator-based transplant so that the volume is not left distorted by muscle that will eventually atrophy. The rectus abdominis donor site is not commonly used because of poor color match and ptosis. The forearm is useful in thin defects or after tissue expansion prior to transfer. For defects that include the zygomaticus muscles and are extensive, the corner of the mouth needs to be suspended statically or dynamically. The latissimus dorsi muscle sparing flap with a slip of neuromyogenous serratus for suspension of the corner of the mouth is a useful intervention. Decision making with respect to facial reanimation is addressed in other chapters. For extensive cheek and intraoral defects, two skin paddles are required. In these cases, the thickness of the skin paddle has to be considered because the cheek is thin and care has to be taken to choose the donor sites to ensure that the two skin paddles together do not produce an excessively bulky reconstruction.
I perform nerve grafting if the facial nerve branches that supply the orbicularis oris or the zygomaticus muscles are sacrificed. In these cases, the posterior, lateral, or medial antebrachial cutaneous nerve (MACN) of the forearm is used as the donor site because the branching pattern allows for a single proximal anastomosis and multiple distal anastomoses. As mentioned previously, involve oculoplastics if there has been prior surgery on the eyelid or there is concern that the patient will have ectropion postoperatively.
SURGICAL TECHNIQUE
Prior to excision of the cheek defect, a template is fashioned that is the same size as the extirpated tissue. Approximately six to eight tacking sites are marked out around the circumference of the defect and are also transferred to the template for transfer to the donor site. This improves the accuracy and speed of the inset. If there is concern about ectropion, the template can be enlarged in the area of the lower eyelid to help prevent ectropion. The template is traced out on the donor site taking into consideration the axis of the pedicle. The template is helpful because it prevents distortion of the face after inset.
Pincushioning is a problem with cheek reconstructions. To help reduce this late complication, the deep portion of the transplant is pulled past the excision line. This maneuver is accomplished with five to six bolster sutures that are placed around the defect to stretch the deep tissue of the skin paddle into the defect. The 2-0 monofilament nonabsorbable suture is used in a half horizontal mattress technique. This suture is passed through the recipient site skin about 1.5 cm from the edge of the excision, then into the deep adipose tissue of the transplanted skin paddle, and then back out through the skin of the recipient site with about 7 mm of travel from where the suture was initially passed. The two ends of the suture are crossed inside a 10 French bolster, and the ends are tied over the bolster with minimal to moderate tension. This approach is thought to help the deep tissue of the transplant slide under the recipient tissue and minimize dead space in a manner that deep sutures are not entirely able to address. Deep 4-0 interrupted resorbable monofilament suture to the adipose tissue, a second interrupted layer to the subdermal tissue, and a third layer in a subcuticular running technique are also used.
To maintain the position of the mouth, it is important to address the SMAS layer. A determination needs to be made with respect to partial versus total resection of the components of the SMAS that support the angle of the mouth and contribute to oral competence. For the cases where the SMAS is partially resected and critical neuromuscular elements are intact, the cut edges of the muscle or the fascia should be tacked back together with a 4-0 monofilament resorbable suture on a small taper needle. Often, the partially resected SMAS cannot be fully reapproximated without producing facial distortion. In these cases, return the partially resected SMAS to its anatomic position and tack it to adjacent intact SMAS. If there is not adjacent SMAS and there is a gap, then use the suture to bridge the resected tissue without reapproximation. The scar from the underside of the skin paddle of the transplanted tissue will scar to the anatomically positioned SMAS and help maintain the remaining SMAS in anatomic position. If the zygomaticus support to the angle of the mouth is resected, the modiolus needs to be supported statically or dynamically. For patients undergoing autogenous transplantation, fascia can be harvested from an adjacent compartment at the donor site or a dynamic neuromuscular unit can be used to provide suspension, and these techniques are covered in another chapter (Fig. 36.3). When performing oral commissure suspension, the anchorage to the zygoma should be secure; plate and screws should be used if necessary. I suspend in the anatomic position of the zygomaticus and use some minor overcorrection.
FIGURE 36.3 This is an image of the left lateral face. The right side of the image is cranial, and the left side of the image is caudal. The commissure can be seen at the top of the image. The serratus muscle is seen crossing the defect from the modiolus to the malar eminence to support the commissure, and the neural anastomosis can be seen in the inferior/posterior aspect of the defect. The skin paddle is reflected anteriorly, exposing the deep surface. The thin sheet of latissimus muscle can be seen on the deep surface from the muscle sparing elevation.
Attention to the lower eyelid is important so that the patient does not develop ectropion as a late effect. The skin paddle should be designed with excess skin and subcutaneous tissue pushing the lid superiorly. The skin paddle should be securely tacked into the circumference of the cheek defect before closing the lid site. The first two sutures in the area of the lid should be toward the lateral then medial canthus. This should produce a soft tissue sling under the lower lid. Then the deep portion of the transplanted skin paddle should be tacked to the orbital rim starting centrally in the midpupillary line. To prevent contraction of the lower lid, temporary sutures can be placed in the lower lid and taped to the forehead.
Few patients need the facial nerve grafted because the facial nerve courses deep to the SMAS. As a result, the end organ (SMAS) is resected before the facial nerve is resected. There are exceptions, patients who require nerve resection for perineural invasion or patients who have an intact but denervated orbicularis oris. For these cases, nerve grafting can be of some benefit. My donor site of choice is the arm. The PACN, the MACN, or the lateral antebrachial cutaneous nerves (LACNs) are used. The PACN is harvested when elevating a lateral arm skin paddle for transplant. The nerve fibers are located over the muscle belly of the digastric in Camper’ fascia. If the arm is not being used as a free tissue donor site, then a curvilinear incision can be made between the brachioradialis and flexor carpi radialis from a side just distal to the antecubital fossa to approximately two-thirds down the forearm to harvest the MACN or LACN. The incision is made to the depth of Camper fascia, and the MACN nerve can be identified and selected for the appropriate branching pattern. A scalpel is used distally that incorporates the fascia so as not to cause wallerian degeneration in the smaller fibers. The LACN can be identified laterally, coursing with the cephalic vein in Camper fascia. This area can be accessed with a scissor spread toward the cephalic vein where the LACN will be colocated. The LACN tends to be larger and has fewer branches. The nerve anastomosis is performed with an operating microscope and 8-0 nonabsorbable monofilament suture. Three simple sutures are placed. If there is not a clear distal neurovascular bundle, then the nerve is drawn into, for example, the orbicularis oris muscle with a suture and left buried within the muscle belly.
The parotid duct may be excised with the cheek defect. For patients who do not have xerostomia and have a functioning parotid gland, there are two alternatives. The duct can be clipped, and the parotid will undergo involution. If the parotid is a functioning gland, I use a small vein graft to reconstruct the duct. An interrupted suture technique is used with an 8-0 nonabsorbable monofilament suture with the assistance of an operating microscope. If the ampulla was excised, the remaining terminus of the duct can be tacked to the margin of the buccal defect with 6-0 monofilament, nonabsorbable suture using a taper needle (Figs. 36.4 and 36.5).
FIGURE 36.4 This image is of the left lateral face. The upper part of the image is cephalic and the lower part of the image is caudal. This is an image from revision surgery 10 months after chemoradiation. There has been atrophy and contracture of the orbicularis oris, and this has reduced lip height. In addition, the lip is longer on the operated side than on the unoperated side. The modiolus is adequately suspended. There is an incision on the lip, and an advancement flap from lateral to medial has been performed along the expected location of the nasolabial crease. The desired result of increasing lip height and decreasing lip length is achieved. In addition, the preauricular cheek skin has been advanced from lateral to medial to reduce the size of the transplanted skin paddle.
FIGURE 36.5 This is an 18-month posttreatment image. The modiolus is in an acceptable position. The cutaneous portion of the lower lateral cheek skin paddle still needs to be reduced and the skin paddle overall needs some debulking. The overall facial symmetry is good. The nose has not rotated into the defect although the patient will need a nasal spreader graft on the left. Because of concerns about long-term contracture, the nasal ala would not be repositioned for several more years.
POSTOPERATIVE MANAGEMENT
All patients have Silastic suction drains placed in the base of the defect. Drains are removed if drainage is less than 30 mL in a 24-hour period. If there is a buccal defect, a suction drain is placed in a dependent location adjacent to the buccal closure that runs parallel to the pedicle and nerve grafts but does not cross these structures. If the patient has undergone resection of the buccal mucosa with the cheek defect, the patient takes nothing by mouth for the first week if he or she has not undergone prior radiation treatment. For patients who have undergone prior chemoradiation, depending on postoperative healing, a period of 2 to 4 weeks should pass before resuming oral intake. During this time, the patient should undergo oral care that can include three times daily oral irrigation with half and half normal saline and 3% hydrogen peroxide. For compliant patients, brushing of the teeth is desirable to improve oral hygiene. The patient remains in hospital for approximately 6 to 8 days and is seen weekly with speech pathology and nursing during the early postoperative period. Should the free flap dehisce, the area is reapproximated with monofilament suture. Three postoperative doses of antibiotics and deep venous thrombosis (DVT) prophylaxis until the patient is ambulating are routinely administered.
COMPLICATIONS
The most common early complications are hematoma or abscess arising from a hematoma. I am aggressive about taking the patient back to the operating room, irrigating the wound, protecting the nerve grafts if present, and reclosing. To prevent hematoma, I place a face lift dressing or place transbuccal mattress sutures using a 2-0 nonabsorbable monofilament run through 10 French Silastic bolsters.
There are a number of late complications that relate to positioning of the adjacent anatomic subunits such as the lower eyelid, lip, oral commissure, and nasal ala. There can also be complications that relate to the bulk of the transplanted skin paddle or difficulties with color match or pincushioning. In my opinion, the best treatment of these complications is prevention. It is important to try to address the issues of the reconstruction with the initial inset, particularly if the patient has undergone or planned for adjuvant radiation since revision surgery can be difficult. The most important structures to deal with during the initial reconstruction are the lower eyelid, the suspension of the commissure, optimization of the remaining SMAS system, and facial nerve grafting. The late revisions that are easier to manage are reduction of transplanted skin paddle bulk, advancement of local cheek tissue to reduce the surface area of the transplanted skin paddle, and resection of the denervated lip to improve symmetry of the oral commissure.
RESULTS
The results with free flap reconstruction of the cheek are generally excellent. The limitations such as skin color, skin texture, and bulk represent the most significant challenges. Debulking and flap augmentation following the initial healing can result in an excellent functional and aesthetic outcome.
PEARLS
• Choose the donor site that has the best color match and the least chance for ptosis to improve blending of the reconstruction into the face.
• Match the size and shape of the skin paddle to the defect to reduce dysmorphism.
• Stretch the deeper adipose layer into the defect with bolsters to reduce pincushioning.
• Support the lower eyelid to prevent ectropion, to protect the cornea, and to have excess tissue available for any revision which may become necessary.
• Carefully reconstruct the remaining SMAS because very acceptable results can be obtained with careful reconstruction of the local muscle aponeurotic system.
PITFALLS
• Because the position of the corner of the mouth is the most important functional and esthetic consideration, failure to support the oral commissure can result in significant functional and cosmetic deformity.
• In spite of the finest reconstructive techniques, the failure to perform a nerve graft at the time of the initial reconstruction may hinder the achievement of an acceptable reconstructive result.
INSTRUMENTS TO HAVE AVAILABLE
• Major head and neck set
• Marking system for templating the defect
• Ruler to assist in positioning of the oral commissure
• Operating microscope for vessels, nerve, and duct
SUGGESTED READING
Jowett N, Mlynarek AM. Reconstruction of cheek defects: a review of current techniques. Curr Opin Otolaryngol Head Neck Surg 2010;18(4):244–254.
Menick FJ. Discussion: simplifying cheek reconstruction: a review of over 400 cases. Plast Reconstr Surg 2012;129(6):1300–1303.
Rapstine ED, Knaus WJ II, Thornton JF. Simplifying cheek reconstruction: a review of over 400 cases. Plast Reconstr Surg 2012;129(6):1291–1299.