Randomized controlled trial to evaluate the treatment outcomes of trasparotid and transmasseteric anterior parotid approaches to treat mandibular subcondylar fractures.

As reported in literature, mandibular condylar fractures accounts up to 17.5% - 52% of total mandibular fractures. There are various surgical approaches available in literature for ORIF of subcondylar fracture. Among extraoral approaches, retromandibular transparotid approach has been the approach of choice for many surgeons. Recently, retromandibular transmasseteric anterior parotid approach has been associated with less facial nerve palsy reported in literature, though there is paucity. So this study was designed to evaluate the efficacy these two approaches for treatment of subcondylar fractures. 53 cases were included and divided into 2 groups: group A in which 26 cases were treated with retromandibular transmasseteric anterior parotid approach and group B in which 27 patients were treated with retromandibular transparotid approach. Patients were randomized into both groups as per computer generated randomization table provided by Department of Biostatistics, AIIMS. These patients were followed up at postoperative day 1, day 7, 1 month and 3 month. Evaluation of facial nerve status was the primary outcome of the study and time taken for fracture exposure, blood loss during exposure, postoperative sialocele or parotid fistula, surgical site infection, scar and radiographic evaluation of fixation site were secondary outcomes.

The mean age of patients in group A and group B was 26.38 (18-52) and 24.11 (18-36) years respectively. Group A consisted of 22 males and 4 females, whereas, group B consisted of 25 males and 2 females. The most common mode of trauma for enrolled patients was road traffic accident, 65.3% in group A and 74% in group B, followed by assault, fall and sports injury was least. 22 patients in group A and 21 patients in group B had unilateral subcondylar fractures whereas, 4 patients in group A and 6 patients in group B were had bilateral subcondylar fracture. In group A, 11 cases had laterally displaced, 7 cases had medially displaced and 8 cases had non-displaced condyle. Similarly, in group B, 14 patients had laterally displaced, 6 patients medially displaced and 8 patients had non-displaced condyle. 19 cases in group A and 20 cases in group B had non-dislocated condyle whereas, 7 patients in each group had dislocated condyle. The mean deviation of condyle in group A and group B was 23.84 and 31.48 degree respectively. Mean preoperative mouth opening in group A and group B was 15.19mm and 19.18 mm respectively. 21 patients in group A and 23 patients in group B had deranged occlusion, whereas, 5 patients in group A and 4 patients in group

had acceptable occlusion. The mean interval between trauma and surgery was 8.3 days and 8.1 days in group A and B respectively.

The results of the study showed that the mean exposure time in group A and group B was 19.88 minutes and 14.48 minutes respectively. The mean blood loss in group A and group B was 9.69mL and 8.98mL respectively. None of the patients in group A had any facial nerve paresis, neither transient nor permanent. However, in group B, 2 patients had transient facial nerve injury postoperatively which resolved after 3 months. In both groups, 2 patients developed sialocele and none of them had parotid fistula. 1 patient in group B had surgical site infection postoperatively, other than that no patients enrolled in study showed any sign of surgical site infection. 3 patients in each group was not satisfied with scar after 3 months. In group A, 3 patients showed plate fracture at 3 month follow up. In all of these patients, osteosynthesis was done with 2 non-parallel 2mm miniplates. In our study, facial nerve injury associated with retromandibular transparotid approach was more as compared to retromandibular transmasseteric anterior parotid approach, though statistically not significant.

It can be concluded that the differences in efficacy of retromandibular transmasseteric anterior parotid and retromandibular transparotid approach are comparable in terms of adequacy of exposure, time taken for exposure, blood loss during exposure, incidence of facial nerve injury postoperatively and other complications like sialocele, parotid fistula, unaesthetic scar and plate fracture postoperatively. Surgical approach for surgical management of condylar fractures should be decided based on level of fracture, anatomic factors of patient, surgical skill of the surgeon and available armamentarium. Further studies with larger sample size can be planned for Comparison of these approaches to further the literature.