Evaluation of the effect of free fibular flap transplantation in repairing mandibular osteoradionecrosis defect in 151 cases

Objective: To investigate the clinical effect of free fibula flap transplantation in repairing the defect of mandibular osteoradionecrosis (ORN). Methods: A total of 151 mandibular ORN patients undergoing free fibular flap transplantation were selected from August 2005 to September 2020 in the Department of Oral and Maxillofacial Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University. Among them, 109 patients were males and 42 patients were females, aged (54.1±10.1) (ranged 31-85) years old. The clinical data of the patients was collected and the survival rate of the flaps and postoperative function were calculated to evaluate the surgical efficacy. The χ2 test was used for difference analysis. Results: Among the 151 patients, mandibular ORN caused by radiotherapy for nasopharyngeal carcinoma accounted for 79.5% (120/151). The average time for mandibular ORN appeared was 5(6) years after radiotherapy. Facial artery [57.2%(87/152)] and superior thyroid artery (50/152, 32.9%) were the main anastomotic arteries in the recipient area. There was no significant difference in the necrosis rates of the two flaps [10.3%(9/87) and 12.5%(5/50), respectively, P=0.949]. The main anastomotic veins in the recipient area were the external jugular vein [48.4%(135/279)] and the common facial vein [26.5%(74/279)]. Twenty-five cases (16.6%) had one vein anastomosed, and 126 cases (83.44%) had two veins anastomosed. There was no significant difference in the flap necrosis rate between the two conditions [20.0%(5/25) and 7.1%(9/126), respectively, P=0.100]. Ninety-seven cases (64.2%) used the peroneal musculocutaneous-fascia composite flap to repair the maxillofacial soft and hard tissue defects. Thirteen cases (8.6%) underwent the restorations with digital virtual surgery design, of which 5 cases were repaired with dental implants at the same time. After the operations, lower respiratory tract infection occurred in 17 patients (11.3%), and upper respiratory tract obstruction occurred in 3 cases (2.0%). The survival rate of the flap after operation was 90.7% (136/151), and 21 patients (13.9%) had flap vascular crisis. Delayed healing of maxillofacial wounds occurred in 33 cases (21.9%). After 3 to 24 months of follow-ups, 110 patients (76.9%) had no fistula inside/outside the oral cavity, 118 patients (82.5%) had an improvement in opening mouth of increasing (≥0.5 cm) after surgery, 135 patients (94.4%) had pain relief, 97 cases (67.8%) could eat normal diet, semi-liquid or soft food, and 137 cases (95.8%) were satisfied or basically satisfied with the treatment effects. Conclusions: The free fibular flap transplantation is an effective method to repair mandibular ORN defects. Preoperative vascular assessment is helpful for the selection of recipient vessels. Facial artery, superior thyroid artery, external jugular vein and common facial vein can be used as the main recipient vessels. The repair of the peroneal musculocutaneous-fascia composite flap facilitates the closure of internal and external fistulas. Digital technology can help to restore the maxillofacial shape more accurately, improve the patient's occlusal and chewing function and enhance the quality of life of mandibular ORN patients.