Resection of oral malignancies with safe margins leads to deficits in various functions like speech, swallowing, mouth opening, etc [1-3]. Thus, adequate reconstruction of the post-resection defect becomes a necessity and a challenge in order to restore both function and aesthetics [4]. Several local, regional, and free flaps are being used presently. The choice of the reconstruction method is chiefly dependent on various factors like the size of the post-resection defect, the age of the patient, the presence of any comorbidities, whether previous surgeries like ipsilateral neck dissections have been done or not, the surgeon’s preference, etc [2-5]. Despite the current advancements in microvascular surgeries, the use of local and regional flaps remains a preferred option for a surgeon, considering the simplicity of the surgical technique and favourable results. The masseter muscle is a muscle of mastication that helps in the elevation of the mandible and is one of the strongest muscles of the human body. Its use in the reconstruction of oral defects was first advocated by Tiwary, Snow, and Langdon in 1989 [2-3]. Its use for reconstruction of oropharyngeal defects was first documented by Conley and Gullane in 1978 [6]. This muscle has also been widely used in cases of facial palsies for reanimation purposes [7]. There are very few studies in the literature dealing with this unique mode of reconstruction of the oral cavity following carcinoma resection in posterior-inferior areas. Thus, the purpose of this study is to evaluate the efficacy of superiorly based masseter muscle flaps in the reconstruction and repair of intraoral surgical defects in patients with early cancer of the posterior-inferior parts of the oral cavity.

The masseteric branches of the maxillary artery (MbMA), facial artery (MbFA), transverse facial artery (MbTFA), and superficial temporal artery (MbSTA) supply the masseter. Based on its diameter, frequency of occurrence, and distribution area, the MbTFA can be considered to be the main branch supplying the masseter muscle. This artery is never encountered during standard comprehensive or selective neck dissection, which makes the harvest of the flap perfectly reliable even after previous or concomitant neck dissection as long as the external carotid artery is not transected. Venous drainage of the masseter muscle is provided by the facial vein, which flows into the internal jugular vein. In cases of previous neck dissection, the pterygoid venous plexus will provide venous drainage as long as the internal jugular vein is preserved. The flap can be harvested as a crossover flap by maintaining the superior zygomatic attachments or as an island flap by transecting both insertions. The only careful step is the elevation of the parotid gland and terminal branches of the facial nerve from the superficial aspect of the muscle. This step, however, is easily performed with adequate exposure; the fascia of the masseter just above the angle of the mandible is incised and dissected free along with the cheek flap to preserve the branches of the facial nerve, and the muscle is freed along its posterior margin from the parotid gland. The detachment of the mandibular or zygomatic insertions is very quickly obtained with electrocautery, and the muscle is ready to be transposed.

A 54-year-old man reported an ulceroproliferative lesion present in the left gingivobuccal sulcus and an enlargement of the submandibular lymph node on the left side. But there is no evidence of fixation or metastasis. An incisional biopsy was carried out, and the histopathology of a well-differentiated squamous cell carcinoma was obtained. A modified Schobinger incision was placed, and a modified radical neck dissection was done (from Level I to Level V) with preservation of the spinal accessory nerve, sternocleidomastoid muscle, internal and external jugular veins, and omohyoid muscle. The masseter muscle is raised and separated from the lateral surface of the mandible. A Marginal mandibulectomy is carried out from the right lateral incisor along with the tumor tissue. The masseter muscle was brought forward medially and sutured to the residual part of the mylohyoid muscle. The floor of the mouth was sutured to the medial aspect of the masseter muscle, the skin flap was repositioned, and layer-by-layer closure was done. Healing was uneventful; the defect underwent spontaneous epithelization and the patient completed postoperative radiotherapy.

Figure1: Outline for the Modified Schobinger Incision.

Figure 2: Modified Radical Neck Dissection Done and The Masseter Muscle Flap was Harvested.

Figure 3: Resected Tumor Along with The Segmented Involved Mandible.

Figure 4: Intraoperative Photo After the Layer Wise Closure.

Figure 5: Masseter Flap At 6-Months Post Op Showing Mucolisation (Arrow).

Post-ablation defects of the posterior-inferior part of the oral cavity, which are small and moderate in size, resulting from the surgery of a tumor in the oral cavity, are presently a challenge to a surgeon while planning for reconstruction. The main objective of reconstruction after ablative surgery in cancer patients is to restore optimum function and aesthetics. Several methods of reconstruction have been recommended in the literature, including skin grafts and true tissue transfer. The masseter flap produces adequate bulk for filling the defect following ablation. It is a one-stage procedure that does not require extensive dissection or result in functional loss. The cosmetic outcome of the flap is acceptable. The disadvantage of the masseter flap is its close proximity to the primary tumor.

The masseter flap offers a reliable method for oral cavity and oropharyngeal reconstruction in selected cases; it is a safe, single-stage procedure that does not require elaborate technique or postoperative care. Especially advantageous are the low postoperative morbidity, low rate of postoperative complications, and good functional results with acceptable cosmetic donor site morbidity.

Conflict of Interest

The authors declare no conflicts of interest.

Funding

Self-funding.

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