Parotidectomy for benign and malignant tumors often results in conspicuous contour abnormalities and soft tissue defects. Immediate reconstruction leads to improved patient satisfaction and local or regional flaps can be used for reconstruction in most cases. This article provides a systematic approach to parotid reconstruction.
Key points
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Reconstruction after parotidectomy is customized to patients’ needs.
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Exposure of both sides of the face during parotidectomy allows accurate reconstruction based on the contralateral side.
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Local and regional flaps can be used for most benign and malignant tumors and the sternocleidomastoid muscle flap is a useful first choice in most cases.
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Reconstruction after radical parotidectomy involves volume restoration, commonly with the supraclavicular artery island flap or free tissue transfer, as well as facial nerve reconstruction.
Introduction
Most salivary gland tumors are located in the parotid gland, and 70% to 80% of these neoplasms are benign. Tumor resection may involve partial, superficial, total, or radical parotidectomy, depending on pathology findings and location. Regardless of the extent of resection, patients are often left with a cosmetic deformity in the preauricular, infra-auricular, and retromandibular regions. This cosmetic deformity can cause disfigurement and decrease patients’ quality of life.
The principal goals of reconstruction after parotidectomy include correcting any facial nerve abnormality, preventing gustatory sweating (Frey syndrome), and restoring facial symmetry and contour. A cosmetically pleasing reconstruction is especially important given the preponderance of benign tumors among a fairly young population. Single-stage surgery improves patient satisfaction, prevents the need for revision surgeries, and has not been shown to interfere with postoperative tumor surveillance. Most parotidectomy reconstructions can be completed with local or regional flaps. This article provides an algorithm for reconstruction of parotidectomy defects using predominantly locoregional flaps and allografts.
Surgical management
The parotid gland is the largest salivary gland. Its deep and superficial lobes are artificially divided by the facial nerve, which courses though it. The superficial lobe contains 80% of the substance of the gland, and approximately 90% of parotid tumors arise here. Most tumors can be removed with a partial parotidectomy. Radical parotidectomy, including resection of the facial nerve, is reserved for malignant tumors with aggressive features and/or perineural invasion.
Preoperative Planning
Preoperative planning for parotidectomy includes fine-needle aspiration and at times MRI or computed tomography, along with appropriate patient counseling. In addition, the senior authors (B.A., B.L.) take preoperative frontal, oblique, and lateral three-dimensional photographs of all patients undergoing parotidectomy ( Fig. 1 ).
In the operating room, both sides of the face are exposed and prepped. When a local flap such as the sternocleidomastoid (SCM) muscle flap will be used, the incision is carefully planned to allow for adequate exposure. The senior authors prefer a short-scar facelift incision (microparotidectomy incision) in most benign tumors. This incision extends from the superior portion of the tragus, around the earlobe, and onto the posterior surface of the concha. They have successfully used this technique in tumors as large as 5 cm. In larger tumors, when access becomes difficult, the incision can be extended along the temporal and/or occipital hairlines. The classic modified Blair incision is rarely used in benign disorders, with the exception of very large tumors.
Reconstruction
After tumor resection, the defect is analyzed and compared with the contralateral side. Most benign tumors can be reconstructed with an SCM muscle flap with or without freeze-dried acellular human dermis. Local fascia flaps including the superficial muscular aponeurotic system (SMAS) and the temporoparietal fascia (TPF) flap are reserved for small contour abnormalities or anterior or superior defects that cannot be reached with the SCM muscle flap. Larger defects requiring significant tissue bulk, such as those from radical parotidectomy, are best reconstructed with axial flaps, such as the supraclavicular artery island (SAI) flap. The anterolateral thigh (ALT) free flap is the most commonly used free tissue flap and is generally reserved for radical defects involving mandibulectomy.
Acellular dermis
Freeze-dried acellular human dermis has gained popularity in parotid reconstruction. After tumor resection, it can be sutured to the remaining parotid tissue to add bulk and fill contour defects ( Fig. 2 ). By acting as a mechanical barrier to aberrant auriculotemporal nerve regeneration, acellular human dermis is associated with a reduced incidence of Frey syndrome. The material is incorporated into surrounding fibrous tissue and minimally resorbed over the first 6 months, after which time its volume remains stable. An increased incidence of seroma has been noted with acellular human dermis; however, the use of prolonged suction drainage reduces seroma formation significantly.
In the senior authors’ practice, acellular dermis is primarily used in conjunction with locoregional reconstruction such as the SCM muscle flap. A thick sheet, folded into no more than 2 layers, is placed superiorly or inferiorly to the flap if extra volume or length is needed. For small defects located anteriorly or superiorly, outside of the range of the SCM flap, acellular dermis is used as a stand-alone reconstruction.
Sternocleidomastoid muscle flap
The SCM muscle flap is the most commonly used flap for parotidectomy reconstruction and is sufficient for correction of most defects ( Fig. 3 ). Like acellular dermis, the SCM muscle flap has been shown to reduce the incidence of Frey syndrome. A significant amount of bulk can be obtained by transposing part of the muscle to fill depressions in the preauricular and infra-auricular areas. Compared with the SMAS flap (discussed later), the SCM muscle flap shows improved correction of contour abnormalities.
Blood supply to the SCM muscle is derived from the occipital artery in the superior third, the superior thyroid artery in the middle third, and the thyrocervical trunk inferiorly. The flap can be superiorly or inferiorly based, or the central portion can be advanced anteriorly. The superiorly based SCM muscle flap is the most commonly used ( Fig. 4 ). The senior authors’ technique involves skeletonizing the SCM muscle and making a vertical incision along the midline portion of the muscle. Care is taken to identify and preserve the greater auricular and spinal accessory nerves (see Fig. 4 ). The distance from the pivot point at the superior portion of the muscle to the edge of the defect is measured, and a horizontal cut is made using electrocautery. The SCM muscle is then rotated into the defect to cover the entire parotid bed and sutured using horizontal mattress sutures. If the posterior pull from the SCM muscle flap causes the SMAS to advance slightly, the skin is undermined anteriorly to prevent dimpling. If the defect is larger or more superior, then a wider and/or longer section of the SCM muscle is transposed. A suction drain is placed, and a small amount of skin is excised if necessary. Atrophy of the SCM muscle may occur with time, so slight overcorrection can be advantageous. In addition, a posterior defect over the region of the muscle harvest can be corrected by advancing the lateral aspect of the posterior belly of the SCM muscle.
Superficial muscular aponeurotic system flap
The SMAS flap is an easily accessible local flap that can be used for small defects ( Fig. 5 ). It also provides a physical barrier for prevention of Frey syndrome, and it is useful for anterior defects that cannot be reached with the SCM muscle flap alone. At the beginning of the parotidectomy, the SMAS can be dissected out between the subcutaneous flap and the parotidomasseteric fascia. After resection, the SMAS can be folded, laid over the parotid bed, and sutured to the remaining parotid tissue and zygomatic fascia. This flap cannot be used in cases in which the tumor involves the SMAS, and it does not provide sufficient soft tissue bulk to fill moderate to large defects. In the senior author’s practice, this flap is rarely used as a stand-alone procedure and is more commonly used to complement acellular dermis and SCM muscle flap.
Temporoparietal fascia flap
A flap based on the superficial temporal artery can also be used as an interposition flap. In this case, the parotidectomy incision is extended into the temporal hair line and a double-layered fascia graft, consisting of the TPF and the deep temporal fascia, is harvested. This graft is pedicled inferiorly, folded over the zygomatic arch, and sutured to the edges of the parotid bed. It has been used to fill gaps larger than 3 cm and may reduce the incidence of Frey syndrome. However, this flap is rarely used in our practice because of the likelihood of injury to the superficial temporal artery during parotidectomy surgery. Furthermore, there is potential for alopecia, damage to the frontal nerve, and hematoma formation.
Fat grafting
Fat can be harvested from the abdomen or thighs and placed in the parotid bed to fill contour defects. It may also be combined with the SMAS flap. The SMAS flap plus fat grafting for reconstruction after malignant parotid tumor resection has been reported with successful take of the fat even after radiation therapy. Disadvantages of fat grafting include donor site morbidity, increased blood loss and operative time, and unpredictable loss of fat.
Cervicofacial advancement flaps
In patients with tumor involving the overlying skin but without large volume deficits, local tissue advancement flaps are used to provide skin coverage and modest bulk. The cervicofacial advancement flap can be used to rotate skin, subcutaneous tissue, and platysma muscle from the neck to the face. This flap is inferiorly based and is designed based on the extent of the defect. For patients undergoing neck dissection, the inferior neck incision can be planned to allow for flap advancement. The posterior inferior limb of the incision extends inferiorly as far as necessary, even onto the chest wall, to provide adequate arc of rotation and tissue coverage. The plane of dissection is supra-SMAS in the face, subplatysmal in the neck, and subcutaneous (supradeltopectoral fascia) if it extends into the chest. The blood supply to the facial portion of the flap is in a random pattern from the subdermal plexus. The platysmal portion of the flap derives its blood supply primarily from submental artery perforators anteriorly. Defects as large as 7 × 6 cm and extending as far superiorly as the supraorbital rim have been reconstructed with this flap.
The cervicofacial flap can be modified to a bilobed configuration. The bilobed flap technique is well known for its use on many areas of the face and neck, and a large bilobed flap has been used for postburn scar contractures in the neck. The senior authors have found a modification of this flap useful for parotidectomy defects involving the overlying skin ( Fig. 6 ). It is based posteriorly in the neck and uses the principles described by Zitelli for the bilobed flap in nasal reconstruction. The primary lobe of the flap is measured to be the same diameter as the defect, and the secondary lobe is approximately half the size of the primary lobe (see Fig. 6 C). The posterior limb of the secondary lobe can be extended and curved slightly away from the base of the flap in order to facilitate rotation into the parotid defect. The primary lobe is rotated into the defect and the secondary lobe is closed primarily. This flap provides excellent color and texture match, although it necessitates an extended incision and relies on a random blood supply.
