A total of 18 patients with massive vascular malformations of the head and neck region were treated with compartmentalization using nonabsorbable sutures followed by injection of a sclerosant agent into each compartment. The indication for compartmentalization was either to stop potentially uncontrollable, life-threatening hemorrhage during the dissection of the lesion or to reduce its vascularity to allow a less dangerous subsequent resection. Compartmentalization was used in both high-flow and low-flow vascular malformations. In this technique, large nonabsorbable sutures are placed deeply in multiple areas within the lesion. The aim is to divide the malformation into multiple compartments by changing the direction of the suturing; in this way the sclerosing agent is provided with a more effective environment. The sclerosant used was either sodium tetradecyl sulfate 3%, absolute alcohol, or both. The total amount of infiltrate varied from 3 to 35 cc, according to the size of malformation. After compartmentalization, swelling was the most noticeable complication. With this technique, it was possible to treat what were considered untreatable malformations using standard techniques and to control the inevitable serious bleeding.