Abstract
Oral cancer is a major public health problem in India. Most patients present with locally advanced disease requiring complex resection and reconstruction strategies. Costs, operating time and availability of expertise are major issues that influence efficient health delivery, especially in developing countries such as India. Technically simple and widely reproducible techniques may be used successfully where applicable, to overcome these issues. The submental artery flap is a well described and acceptable alternative to the radial artery forearm free flap in oral cavity reconstruction. Researchers have demonstrated its technical ease of performance and reproducibility amongst trainees. Here the authors describe the bipaddled submental artery flap, a modification of the standard flap, which can be used to provide lining as well as skin cover for a full thickness cheek defect. Two skin paddles are fashioned taking advantage of the vascular anatomy of the submental vessels.
Oral cancer is a major public health problem in India and most patients present with advanced disease requiring complex management strategies. Microvascular free flaps have become popular in reconstructing complex post resection defects in the head and neck, but factors such as cost, expertise, and logistics (e.g. operating time) are some of the serious concerns in the public healthcare delivery system in India. Simple and technically reproducible alternatives are urgently needed to tackle these issues. The submental artery flap is a well described axial pattern flap that is increasingly being used in head and neck reconstruction because of its obvious advantages. The authors describe how they perform a bipaddled submental artery flap for reconstructing a full-thickness cheek defect following resection for oral cancer.
The submental artery is a branch of the facial artery, and is about 1.0–1.5 mm in diameter. It courses along the undersurface of the mandible and, in most cases, runs deep to the anterior belly of the digastric and just superficial to the mylohyoid muscle as it enters the submental region. The artery then gives off one to four perforators that pierce the platysma muscle and supply the subdermal plexus. The location of the critical perforator is variable and can be lateral or medial to the digastric muscle. Venous drainage is through the submental vein that drains into the facial vein.
The patient was a 55-year-old female with a tobacco chewing habit. She had an exophytic tumour involving the left buccal mucosa, gingivobuccal sulcus and infiltrating the skin of the cheek. There was no destruction of the mandible on CT scan. The stage was well differentiated squamous cell carcinoma of left buccal mucosa cT4aN0M0. She underwent wide local excision with marginal mandibulectomy, supraomohyoid neck dissection and reconstruction using a bipaddled submental artery flap. Resection margins were confirmed to be histologically free of tumour on frozen section. The technical details are outlined below.
Following preoperative planning, the dimensions of the proposed defect are assessed ( Fig. 1 ). A reliable alternative is also planned. In this patient the alternative plan was to use the anterolateral thigh flap since the radial forearm flap was unavailable for use. Preoperative Doppler assessment of the location of the perforators may be useful. An elliptically oriented submental flap is planned that extends from one angle of mandible to the other. The area of ellipse used was approximately 20 cm 2 . The extent of submental skin available is determined by the ‘pinch-test’ which will allow primary closure of the donor area.
Skin incisions are marked appropriately for resection of the primary tumour and neck dissection. Flap harvest and neck dissection may proceed simultaneously. Whilst performing the neck dissection, certain deviation from the conventional technique is mandatory.
For level 1A, the flap is elevated off the contralateral anterior belly of the digastric, then taking care that no lymphatic tissue is left attached to the flap, level 1A is cleared. The ipsilateral anterior belly of the digastric is cut close to its mandibular attachment and at the intermediate tendon.
For level 1B, the submental vessels are dissected off the submandibular gland and the branch that supplies the gland is ligated or clipped. They are carefully traced to the facial artery and vein. The marginal mandibular nerve is carefully preserved.
For level 2, the facial artery take off and the facial or internal jugular vein are not ligated unless continuity can be re-established using microvascular techniques. Radical neck dissection is a relative contraindication for use of the ipsilaterally based flap.
For levels 3–5 there is no requirement for modification of the conventional technique. The authors take care to preserve the external jugular vein which has communications with the facial vein draining the submental vein.
Having completed the resection of the primary tumour and neck dissection, the flap should now easily swing into the defect either over the mandible (the authors’ preference) or through a tunnel created between the mylohyoid and the inner cortex of the mandible. The authors begin by suturing the contralateral end of the flap to the posterior most part of the buccal mucosal defect and work their way anteriorly. The flap can be raised as a bipaddled flap at the outset, but the authors prefer to split the single paddle flap into two paddles after the harvest and inset of the distal portion of the flap. Anatomically the critical perforator is located on one or other side of the ipsilateral anterior belly of the digastric muscle. A full thickness skin incision (platysma and subcutaneous tissue is left intact) is made such that this critical perforator falls within the distal paddle of the flap ( Fig. 2 ). Judicious undermining of the edges of the skin paddle on either side of this incision prevents the skin edges from being inverted at the time of suturing. This split allows the proximal paddle to be folded to the exterior to provide the skin cover. For obvious reasons, the proximal paddle is smaller than the distal. A No. 8 or 10 infant feeding tube is placed between the paddles and the flap is sutured in place. The donor area is closed primarily after leaving a suction drain. The authors take care to avoid pressure dressings since this may cause venous congestion.
