Treatment of the Scalp Avulsion by Ultrasonic Surgical Aspiration

ABSTRACT

A large scalp avulsion injury may lead to severe bleeding and may cause trauma to the forehead, eyebrows and periauricular tissue. This may bring fatal results aesthetically and functionally. Severe deformity may result after treatment and may also lead to psychological trauma disabling the patient to lead a normal social life. The scalp is made up of 5 layers histologically. They are the skin, subcutaneous fat, galea aponeurotica, subepicranial space and the periosteum. The external 3 layers of the scalp exist fairly independent of the cranial bone and function as one structure in the movement of the frontalis muscle and the occipitalis muscle. Therefore, scalp avulsion injuries usually involves the 3 outer layers along with the subepicranial space but may sometimes include the periosteum as well. Treatment methods are split thickness skin graft, replantation after defatting of the avulsed flap, composite graft and microsurgical procedures. Only methods that can preserve the hair are composite graft and microsurgery. However, limitations of composite graft and the environment of the donor and degree of vessel injury of the donor may limit microsurgical procedures. The authors report 1 case of scalp avulsion injury involving the parietal area where ultrasonic surgical aspiration was used to defat the avulsed flap and grafted onto the donor site. At the time of injury, the size and degree of vessel injury of the donor site was not suitable for a composite graft or microsurgery. Therefore, an ultrasound liposuction machine(for ultrasound assisted lipoplasty) was first used on the avulsed flap before replantation after defatting to minimize hair loss. This procedure has almost no traumatic effect on hair loss and distribution and although it may decrease the density of hair follicles, it does not lead to irregular patterns of hair loss. The avulsed flap was transplanted after minimizing hair follicle injury while removing the subcutaneous fat layer of the avulsed flap. On 1 year follow-up postoperatively, although thinning of the hair and decreased density was noticed, but regrowth of the hair was confirmed.