Thirty patients were included in this study; two of them draped off the follow up, and one of them preferred the conservative treatment upon ORIF. Twenty-nine cohort (16 in the RMA group, 13 in the SMA group) with unilateral subcondylar fracture were consecutively included. Demographics and fractures characteristics are shown in Table 1. Of the study population, 23 were male (79.3%), and 6 were female (21.7%). The patient ranged in age from 18 to 69 years, with an average age of 37.2 ± 14.4 years. All patients completed 6 months of follow-up, ranging from 6 months to 16 months. Sixteen patients (55.17%) were treated with RMA, and 13 (44.82%) were treated utilizing the SMA approach. Both groups were treated consecutively by one surgeon. Intra-operative bleeding was minimal, and none of the patients required a blood transfusion. In four cases of the retromandibular group, the retromandibular vein was sectioned and retracted posteriorly. Operative time in retromandibular patients was shorter than submandibular patients, but the difference was not significant. The parotid fistula was not detected in any case. The facial nerve was encountered in both groups, and temporary weakness was seen in three patients. No permanent facial nerve weakness was detected at the end of the follow-up time. Postoperative malocclusion was found in two patients and was treated by elastic traction. Frey’s syndrome, wound infection, abscess, pus discharge, or cellulitis were not detected. Concomitant fractures were treated with a suitable osteosynthesis set.
Helkimo index was conducted to evaluate the patients. In patients with retromandibular approach, AiO was found in 12 patients, whereas the AiI was found in 4 patients. However, the objective clinical finding DiO, I, II were found in 2,10 and 4, respectively. Patients treated with submandibular approach had AiO in 7 patients, while the DiI was found in 5 patients table 5.
3.1 Radiological assessment:
The measurement and parameter between the mean of the fracture and non-fracture side for each approach were tested with an independent t-test and listed in table 6, 7. The intercorrelation coefficient between the two independent observers was 8.5, indicating that excellent reliability.
On RMA group, the horizontal, vertical, and midsagittal condylar angulation on the fracture side were (10.7 ± 2 °), (61.7 ± 19 °), and (72 ± 7 °), whereas on the patients with SMA fracture side were (8.4 ± 2 °), (57.8 ± 11 °), and (64.2 ± 9 °), respectively. However, the condylar position to the horizontal plane on RMA was (2.1 ± 0.7 mm) and on SMA patients was (3.3 ± 0.7 mm). The condylar position to the vertical plane in RMA’s fracture side was (7.7 ± 4 mm); however, on SMA was (7.6 ± 1.7 mm). In addition, the condylar position to the midsagittal plane on RMA was 52.9 ± 4 mm and on SMA was 46 ± 3.6 mm.
The mediolateral condylar inclination to the horizontal plane on SMA was significantly lower than with RMA (P = 0.02). Furthermore, the anteroposterior condyle inclination to the midsagittal plane was lower on SMA than on the RMA group (P = 0.01). The mediolateral condyle position was higher on the RMA than SMA (P =0.001)
Regarding the joint space, the differences between the fracture sides of the SMA and RMA was tested, the superior, medial, anterior, and posterior joint spaces on SMA patients were 3.2 ± 1 mm, 1.8 ± 0.7 mm, 2.5 ± 0.7 mm, and 1.9 ± 0.6 mm, whereas on RMA’s fracture side were 2.3 ± 0.7 mm, 2.6 ± 1 mm, 2.7 ± 0.6 mm and 2.2 ± 0.4 mm.
On the other hand, the joint spaces were tested to find the correlation between condylar position and inclination. The medial joint space was positively related to the condylar mediolateral position in both approaches (P < 0.05). However, a positive relation was detected on SMA between the anterior joint space and the anteroposterior condylar position (P = 0.008 ). Furthermore, the superior joint space had a positive relationship with the vertical condylar position on SMA patients (P = 0.004) (Table 8).
In comparing the 3D finding and the Helkimo index. A negative relationship was identified between the mediolateral condylar angulation and Helkimo Ai (subjective) and Helkimo Di (objective) on SMA (P < 0.05). However, on RMA, the same condylar angulation was significantly related with Helkimo Ai. Furthermore, the mediolateral condylar position had a negative relationship with the Helkimo Ai on the submandibular approach (table 9).