Trapezius Osteomusculocutaneous Island Flap for Reconstruction of The Anterior Floor of The Mouth and Mandible
W. R. PANJE
Indications for use of the trapezius osteomusculocutaneous island flap are (a) anterior mandibular defects, (b) compound defects (i.e., floor of mouth, tongue, or buccal area) in addition to bone (mandibular defect), (c) osteoradionecrosis, and (d) facial contouring in which bone is necessary.
This flap offers the following advantages over previous approaches: (a) it has the potential of a one-stage immediate reconstruction; (b) it offers the alternative of available skin, muscle, or bone for reconstruction of defects of the lower two thirds of the face and oral cavity; and (c) it eliminates the need for microsurgical transplantation of tissue. In addition, in patients in whom oncologic surgery has resulted in denervation of the trapezius muscle, the trapezius osteomusculocutaneos island flap has the advantage of using the already paralyzed trapezius muscle without the need for damaging additional muscles (such as the chest muscle in the pectoralis bone flap).
Multiple arteries supply the trapezius muscle, but the major blood supply is provided by the transverse cervical artery arising from the thyrocervical trunk (3). The transverse cervical artery begins deep to the sternal head of the sternocleidomastoid muscle, crosses the posterior triangle, and enters the trapezius muscle on its deep surface about 4 cm medial to the acromion. The artery is identified easily as it passes deep to the posterior belly of the omohyoid muscle (Fig. 195.1).
The transverse cervical vein usually travels in the same fascial plane as the artery; however, the vein can travel superficial to the omohyoid muscle. If it is seen in this area, it should be preserved. It usually empties into the subclavian vein 2 to 3 cm lateral to where the thyrocervical trunk originates from the subclavian artery. The vein is usually the limiting factor in extending the arc of rotation of this flap.
The accessory nerve generally enters the trapezius muscle in the area of the vascular pedicle. Because of its multiple innervations of the muscle, the nerve usually can be preserved if properly dissected.
To use the scapular spine as part of this compound flap, the trapezius muscle attachment to the scapular spine must be preserved. Accessory nutrient arteries penetrate the scapular spine at the fascial attachment of the trapezius muscle to the spine (4).