Venous drainage of free flaps following radical neck dissection.

Large tissue defects may occur following head and neck surgery. When combined with ipsilateral radical neck dissection the venous drainage of a free flap used to cover the defect may be compromised. Twelve patients having radical neck dissections underwent on-table venography to study the pattern of venous drainage of these flaps. The predominant drainage pattern is initially in a cephalic direction, then across the midline and finally in a caudal direction on the contralateral side of the neck. Venous drainage to the contralateral side of the neck may be a determinant of flap survival. In order to facilitate venous drainage following free flap procedures, patients should be positioned so that the contralateral internal jugular vein is not compressed. Drains should be placed caudal to the microvascular anastomoses in order to minimize interference with the cephalic direction of venous drainage. Any patient having a radical neck dissection requiring a central venous catheter should have it placed ipsilateral to the neck dissection. Thrombosis around a contralaterally placed cannula may significantly increase head and neck venous pressure.