The submental island flap is a reconstructive option in head and neck surgery. It involves transferring a section of skin, fat, and muscle from the area under the chin to repair defects elsewhere. This technique provides a local tissue source for reconstruction, which can be particularly useful after the removal of tumors, following trauma, or for correcting congenital anomalies. The flap is designed to maintain its own blood supply, allowing it to survive and integrate into the new site.
Understanding the Submental Island Flap
The submental island flap is named for its anatomical location and harvesting method. The “submental” region refers to the area beneath the chin, specifically within the submental and submandibular triangles of the neck. The term “island” signifies that the tissue is isolated from its surrounding connections, except for a pedicle containing its blood supply, allowing it to be moved while remaining viable.
The viability of this flap relies on a consistent blood supply primarily from the submental artery, a branch of the facial artery. This artery originates from the facial artery below the mandible, near the submandibular gland. It courses forward and medially, supplying the skin and platysma muscle. The submental artery measures 1 to 2 millimeters in diameter and is 5 to 8 centimeters long. Venous drainage is provided by the submental vein, which drains into the facial vein.
It is thin and pliable, allowing for good functional and aesthetic outcomes, particularly in areas requiring flexibility. The skin from the submental area also offers a favorable color and texture match for facial skin, aiding in a more natural appearance post-reconstruction. The size of the flap can vary, with reported dimensions up to 10 x 16 centimeters, depending on neck laxity and the ability to achieve primary closure of the donor site.
Primary Uses in Head and Neck Reconstruction
The submental island flap is frequently employed to reconstruct defects in various areas of the head and neck. Its versatility makes it a valuable option for repairing soft tissue deficiencies that result from the removal of cancerous tumors, traumatic injuries, or congenital conditions.
A common application of the submental island flap is in the oral cavity, where it is used to reconstruct defects of the tongue, floor of the mouth, buccal mucosa, and palate. It has been successfully used for mobile tongue reconstruction, even for larger defects such as those resulting from a hemiglossectomy, which helps restore mobility and function for speech and swallowing.
Beyond the oral cavity, the flap also finds use in reconstructing defects of the pharynx, including the oropharynx and hypopharynx. It can also be applied to facial skin defects. The flap’s reach allows it to extend to various sites, including the chin, lips, midface areas, or to cover hardware used in spine surgery.
The submental island flap can be adapted for more complex reconstructions. For instance, an osteomyocutaneous variant, which includes a small rim of bone from the inferior part of the mandible, can be used to reconstruct small composite defects of the mandible, maxilla, or orbit. In male patients, the flap can be de-epithelialized to address concerns about hair growth at the recipient site.
The Surgical Approach
Performing a submental island flap involves several careful steps, beginning with patient positioning and flap design. The patient is placed in a supine position with the neck extended to provide optimal surgical access. A handheld Doppler may be used to identify the cutaneous perforators, small blood vessels that supply the skin, located near the mandibular arch and anterior belly of the digastric muscle.
The flap is designed as an ellipse in the submental area, with its upper border drawn along the inferior edge of the mandible. The maximum width of the flap is determined by a “pinch test,” which assesses how much skin can be taken from the donor site while allowing for direct, tension-free closure. The incision is made through the skin and fat, down to the platysma muscle, and dissection proceeds in a subplatysmal plane.
During the elevation of the flap, the ipsilateral submandibular gland and both anterior bellies of the digastric muscle are identified. The facial and submental vessels are carefully identified and dissected, often lying deep to the superior aspect of the submandibular gland. The overlying segment of the ipsilateral anterior belly of the digastric muscle may be included with the flap to protect the terminal vascular supply, and the platysma muscle is often sutured to the skin paddle to further protect the cutaneous perforators.
Once the flap and its vascular pedicle are fully mobilized, care is taken to protect the marginal mandibular nerve, which runs close to the area and, if injured, can affect lower lip movement. The flap is then transferred to the recipient site, through a tunnel created beneath the skin or directly into the oral cavity. The method of transfer and any additional maneuvers, such as dividing the facial artery or vein to increase the flap’s reach, depend on the specific location and size of the defect. The donor site in the neck is then closed, with wide undermining of the inferior flap to ensure a tension-free closure, and suction drains are placed.
Patient Experience and Considerations
Following submental island flap surgery, patients experience a recovery period involving a hospital stay, pain management, and a gradual return to normal activities. Hospital stays typically range from 8 to 14 days. Pain is managed with medication, and patients are advised to begin a clear liquid diet within 24 hours, progressing to a soft diet after about one week.
Potential complications can arise, although the submental island flap is considered reliable. Flap-specific complications may include partial or, less commonly, total flap necrosis (tissue death due to insufficient blood supply). Other issues include flap dehiscence (where the surgical wound reopens), or infection at either the donor or recipient site. Nerve injury is a possibility during dissection, with the marginal mandibular nerve being a particular concern; injury to this nerve can lead to a loss of lower lip depression. Donor site complications are minimal but can include swelling, numbness, or dehiscence of the donor site wound.
For cancer patients, oncological safety is a significant consideration when using the submental island flap. There has been historical debate about the risk of transferring cancerous lymph nodes from the neck to the reconstructed site. However, current understanding suggests that with careful patient selection and meticulous surgical technique, the flap can be used safely, particularly in patients with clinically node-negative necks (no obvious signs of cancer spread to the lymph nodes). Surgeons often perform an ipsilateral selective neck dissection (removing lymph nodes from the same side as the flap) after the flap has been harvested to ensure cancerous tissue is removed. Studies have shown no increased risk of locoregional tumor recurrence in carefully selected patients, even in some cases with pathologically positive lymph nodes, provided appropriate postoperative adjuvant treatment is given.