The anatomical basis of the osteo-musculo-cutaneous trapezius flap in mandibular reconstruction.

The osteo-musculo-cutaneous trapezius flap has seen its indications in mandibular reconstruction reduced since the appearance of micro-anastomotic flaps. However, it may still be useful when the patient has marked atheroma contraindicating a free flap. While the arterial supply of this flap is well known, the same is not true for its venous drainage. The preservation of the accessory nerve and its limits in mandibular reconstruction has been little studied. We carried out a study on 30 subjects (60 cadaveric dissections of trapezius flaps) in order to address these questions. The study has been completed by a surgical series of five patients. The cadaveric study allowed demonstration of the variability of venous drainage of this flap, which depended on the external jugular vein in 80% of cases, the subclavian vein in 12% of cases and on both veins in about 8% of cases. The accessory nerve in one third of cases passed through the middle of the arteriovenous pedicle making its preservation impossible. The segment of the scapular spine allowed reconstruction of about 9 cm of mandible including the mental protuberance in 95% of cases. The surgical study confirmed the data of the cadaveric study and showed the value of this flap when free flaps are contraindicated.