OBJECTIVE: To study the hemorheology of island flap after ischemia-reperfusion injury and modulation of dexamethasone. METHODS: Sixty Wister rats were made ischemia-reperfusion injury model, and divided into two groups randomly(Group I: intraperitoneal injection of normal saline 2 ml/kg as control group; Group II: intraperitoneal injection of dexamethasone 5 mg/kg as experimental group). Flap survived areas were measured and neutrophil necrosis numbers in flaps were counted. Erythrocytes and neutrophil hemorheology were observed. RESULTS: Area survived flap in group II was larger than that in group I. Neutrophil necrosis numbers were less in group II than in group I (P lt; 0.05). Whole blood hyposhear viscosity, erythrocyte aggregation, Casson yield stress and nerutrophil adhesion ability were higher in group I than in group II (P lt; 0.05); and the neutrophil deformability was lower in group I than in group II. CONCLUSION: Flap inchemia-reperfusion can increase erythrocyte aggregation index and neutrophil adhesion ability. Dexamethasone can improve these and decrease neutrophil necrosis numbers, so as to prevent flap from ischemia-reperfusion injury.
OBJECTIVE To repair facial and neck scar using tissue expanding technique. METHODS From January 1991 to January 1995, 16 cases with facial and neck scar were treated. Multiple tissue expanders were put under the normal skin of facial and neck area, after being fully expanded, the scars were excised and the expended skin flaps were transplanted to cover the defects. The size and number of tissue expanders were dependent on the location of the scars. Normally, 5 to 6 ml expanding volume was needed to repair 1 cm2 facial and neck defect. The incisions should be chosen along the cleavage lines or in the inconspicuous area, such as the nasolabial fold or submandibular region. The design of flap was different in the face and in the neck. In the face, direct advanced flap was most common used, whereas in the neck, transposition flap was often used. Appropriate tension was needed to achieve smooth and cosmetic effect. It was compared the advantages and disadvantages of several methods for repair of the defect after facial and neck scar excision. RESULTS Fifteen cases had no secondary deformity after scar excision. Among them, 1 case showed blood circulation disturbance and cured through dressing change. Ten cases were followed up and showed better color and texture in the flap, and satisfactory appearances. CONCLUSION Tissue expanding technique is the best method for the repair of facial and neck scar, whenever there is enough expandable normal skin.