Many reports of the trapezius myocutaneous flap have centered on a single form of the flap. However, three distinct myocutaneous segments—the superior, the lateral island, and the extended island flaps—can be harvested from the trapezius muscle and its overlying skin.¹ In 1972, Conley described the superior trapezius flap, based on the paraspinous perforating branches of the posterior intercostal vessels.² Panje and Demergasso described the lateral island trapezius flap, based on the transverse cervical vessels.^3,4 Mathes and Nahai described the vertical trapezius myocutanous flap in 1979.⁵ Baek et al. described the lower island flap, based on the transverse cervical vessels, in 1980.⁶

The role of the trapezius flap in reconstruction of defects of the head and neck remains relegated to salvage cases or those selected patients with significant morbidities who otherwise cannot withstand extended operations. One of the main reasons why this flap continues to lack popularity is due to the positioning of the patient to raise the flap as well as the potential for vascular compromise to the skin island. Given the location of defects in the head and neck, the use of the trapezius flap requires repositioning the patient from a supine position to a prone position to harvest and then repositioning the patient for the inset of the flap. The need for multiple repositioning can sometimes be avoided when the preparation of the defect and raising of the flap can be carried out with the patient in the lateral decubitus position.

The trapezius flap can be used to reconstruct numerous defects in the head and neck region ranging from defects in the oral cavity, resurfacing of various sites in the neck, and coverage of mandibular and temporal defects.

Anatomy

The trapezius muscle is a triangular muscle that covers the back of the neck and shoulder region and extends inferiorly in the back. It arises from the medial third of the superior nuchal line of the occipital bone, the external occipital protuberance, the ligamentum nuchae, the spine of the seventh cervical vertebra, the spines of all the thoracic vertebrae, and the corresponding supraspinous ligament. The upper part of the trapezius passes obliquely downward, laterally and forward to the lateral third of the clavicle. The middle part passes transversely to the medial edge of the acromion and the upper border of the spine of the scapula. The lower part passes obliquely upward and laterally to terminate in the tubercle at the medial end of the spine of the scapula.⁷ The actions of the trapezius muscle can be divided based on the region, the upper region elevates the shoulder, the middle retracts the scapula and aids in the abduction of the upper extremity, and the lower portion aids in the depression of the scapula.

The blood supply to the trapezius flap had been a source of confusion in the literature for many years. Netterville and his colleagues are credited with clarifying the blood supply to the flap in their publication of a cadaveric study published in 1991.⁸ The skin overlying the trapezius muscle receives its blood supply from four sources: the transverse cervical artery, the dorsal scapular artery, the intercostal perforators lying just off the midline, and the branches from the occipital artery.

The blood supply to the trapezius muscle and overlying skin is primarily from the superficial and deep descending branches of the transverse cervical artery, as well as the occipital artery. The superficial descending branch arises directly from the thyrocervical trunk in 75–80% of cases and is known as the transverse cervical artery.⁹ The dorsal scapular artery arises from the subclavian artery in 75% of cases; however, in 25% of cases, it arises from the transverse cervical artery, and in these cases, the vessel is named the deep descending branch of the transverse cervical artery, and the junction of the two descending branches is the cervicodorsal trunk. The transverse cervical artery enters the trapezius muscle at the base of the neck and descends vertically along the deep surface of the trapezius. The dorsal scapular artery runs under the levator muscle before it divides, giving a major branch and a descending branch. The major branch exits between the rhomboid major and minor to gain access in the deep surface of the trapezius to supply its lower trapezius. The descending branch continues under the rhomboid major muscle and does not supply the trapezius.

The neural supply to the trapezius muscle comes from the spinal accessory nerve.

Flap harvest

• The flap is raised with the patient in either the prone position or in the lateral decubitus position.
• When the flap is to be raised with the patient in the lateral decubitus position, using a beanbag helps to facilitate the positioning as well as securing the patient.
• The skin paddle component of the flap is positioned by measuring the location of the defect from the pivot point in the shoulder.
• Once the measurement from the pivot point to the defect is measured, the information is then transferred to the trapezius. The marking for the skin island should overlie the trapezius muscle.
• The incision is begun on the lateral aspect of the skin flap and carried down to the fascia of the trapezius muscle.
• The positioning of the skin island is checked to be sure that it is placed over the muscle. The preference is that the entire skin island is placed directly over the muscle; if this is not possible, the skin paddle is usually not extended further than 15 cm below the inferior tip of the scapula.
• Once the positioning of the skin island is confirmed, the incision is extended superiorly towards the base of the neck.
• The skin flap is elevated laterally until enough exposure is performed to enable elevation of the myocutaneous trapezius flap.
• The medial skin is then elevated medially towards the spine with the inferior aspect around the previously marked skin island.
• The skin paddle is then sutured to the fascia of the muscle to minimize shearing of the skin island from the underlying muscle.
• Incising the muscle around the skin p/>
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