Free Flap in Head and Neck Reconstruction
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Following total maxillectomy with orbital exenteration, the defect is reconstructed with vertical rectus abdominis free flap. The length of the flap required is determined by measuring from the top of the orbit down to the hard palate and then across to the buccal mucosa. The width is the distance between the Eustachian tube orifice posteriorly and the nasal spine anteriorly. The flap is raised as a vertical ellipse of abdominal skin perfused by vessels which arise from the inferior epigastric vessels and perforate the rectus abdominis muscle. A large segment of the left rectus muscle is therefore raised with the skin.
The thin pliable skin of the front of the forearm is used in radial forearm free flap. The high degree of vascularity, flexibility, and reliability is the main reason for popularity of the flap in head and neck reconstruction. The nerve can be included within the flap, thereby making it a sensate flap. The flap usually used in the cover of the raw area in oral cavity and palate. The radial forearm flap can be divided into two epithelial surfaces separated by a de-epithelialized zone for providing inner and outer lining. A large area of the scalp can be covered with this flap. Similarly, skull base defects can also be covered. A tubed RFFF is used to reconstruct a laryngopharyngectomy defect. The thin pliable tissue from this donor site is more readily tubed than is a thicker musculocutaneous flap. This method of reconstruction offers distinct advantages over free jejunal autograft. Reconstruction of total laryngopharyngectomy defect with a tubed radial forearm free flap following total laryngopharyngectomy and bilateral neck dissection is performed. The length of the defect determines the length of the required free flap. The width of the flap is different at each end. The diameter of the upper lumen is approximately 4 cm giving a circumference of approximately 12 cm while the lower lumen has a circumference of 3 cm with circumference 9 cm. A flap of 14 cm long with width 9 cm distally and 12 cm proximally is planned, elevated, tubed with skin inside, anastomosed cranially and caudally with pharyngeal and esophageal lumen respectively; vascular anastomosis is performed as well.
The rectus abdominis musculocutaneous flap has an important role in head and neck reconstruction as it is easy to harvest with long vascular pedicle and it is reliable. The flap is supplied by deep inferior epigastric artery and vein. The rich vascularity allows greater flexibility and more accuracy in contouring the flap to the surgical defect. The flap is harvested with the patient in supine position and a two-team approach can be used. The most commonly used flap design is transverse rectus abdominis musculocutaneous flap. This flap provides excellent lining for the oral cavity following total or extended total maxillectomy.
Scapular and parascapular flap has the advantage of its length and large caliber of the vascular pedicle and large amount of skin can also transferred. Additionally, the flap can be combined with surrounding muscles, namely, latissimus dorsi and serratus anterior muscles and adjacent segment of rib. De-epithelized scapular and parascapular flap is used for soft tissue augmentation to restore facial contour. Hard palate and orbital floor can also be reconstructed.
The fibula can be transferred both as a free osseous and as a free osteocutaneous flap. The donor site is further away from head and neck region. The width of the skin paddle is limited by the ability to achieve primary closure. The most important application of the fibular flap is the reconstruction of the mandibular defect. The long straight bone can be contoured to match the mandibular defect. The successful placement of a lower dental prosthesis to restore mastication is possible with this procedure.
The anterolateral thigh flap elevation takes place further away from head and neck where ablative procedure goes on at the same time. The loss of donor skin causes little morbidity. A linear scar usually results following this procedure. Covering the soft tissue defect over the lower jaw is usually achieved by this flap.