Senior Resident, Oral and Maxillofacial Surgery, All India Institute of Medical Sciences, Raipur.
Professor, Department of Physiology, All India Institute of Medical Sciences, Raipur.
J Oral Maxillofac Surg. 2024 Sep;82(9):1076-1087. doi: 10.1016/j.joms.2024.05.009. Epub 2024 May 29.
Facial nerve (FN) dysfunction is a potential complication during open reduction of mandibular condylar fractures.
The purpose of this study was to measure and compare the postoperative FN function following transparotid (TP) and transmasseteric anterior parotid (TMAP) operative approaches in open reduction and internal fixation of condylar fractures using electromyogram.
STUDY DESIGN, SETTING, SAMPLE: A randomized controlled clinical trial was designed. The study was conducted in a single tertiary-care hospital in the inpatient setting. Patients aged above 18 years with unilateral condylar fracture of the jaw or bilateral condylar fractures undergoing surgery on only 1 side were included. Patients were excluded if they had fractures of the head, bilateral condylar fractures with surgery planned on both sides, a previous history of surgery in the retromandibular area, existing lacerations to approach condyle, preoperative signs of FN weakness, or a history of parotid surgery.
The predictor variable was the operative approach and the subjects were allocated randomly to TMAP and TP.
MAIN OUTCOME VARIABLE(S): The primary outcome variable was postoperative FN function in the surgical approach employed using the House-Brackmann scale and electromyography (EMG) to record any subtle weakness in nerve function. The FN function is recorded at 3 time intervals postoperatively 1 week (T1), 1 month (T2), and 3 months (T3). The secondary outcomes studied were operating time and any other complications recorded.
Age, sex, fracture pattern with classification of condylar fractures into condylar neck or base fractures according to Loukata et al. Any associated fracture of mandible describing the anatomical location viz symphysis and parasymphysis (anterior mandible), body, contralateral condyle or greater than 1 associated fracture were recorded. Similarly, the presence or absence of any associated midface fracture was also recorded to suggest that the study participants were homogenous in all aspects.
Analytical statistics included χ test, t-test, and repeated measures ANOVA followed by post hoc test to compare EMG data (mean power and mean amplitude) between 2 operative approaches (TP vs TMAP) for facial muscles including frontalis, oculi, and buccinator at different time intervals (T0, T1, T2, T3). Patients within each group were also analyzed to check for nerve recovery occurring during the follow-up period. The level of significance was set at P < .05.
The study sample was composed of 22 patients with a mean age of 32.82 ± 11.21 years in TMAP and 27.82 ± 8.54 years in the TP group respectively (P = .26); male predominance of 81.8 and 90.9% in TMAP and TP group respectively (P = .53) was noted. The FN deficit as assessed by the House-Brackmann scale clinically, was at 54% (T1), 36.4% (T2), and 9.1% (T3) for the TP group and 27% (T1),9% (T2), and 0% (T3) for TMAP group; however, the results were statistically insignificant (P = .31). In surface EMG evaluation, the mean power for the frontalis muscle was significantly higher in the TMAP approach at the T3 time (105.03 ± 9.7 vs 89.56 ± 10; 95% confidence interval -24.28 to -6.65 with P value = .002). TP approach was faster with a mean exposure time of 9.9 minutes.
The results show that both approaches give comparable long-term results with the TMAP group showing better frontalis muscle activity.
面神经（FN）功能障碍是下颌骨髁突骨折切开复位的潜在并发症。
本研究旨在通过肌电图比较经皮（TP）和经咬肌前腮腺（TMAP）两种手术入路在髁突骨折切开复位内固定术后的 FN 功能。
研究设计、设置和样本：设计了一项随机对照临床试验。该研究在一家三级保健医院的住院环境中进行。纳入年龄大于 18 岁的单侧下颌骨髁突骨折或单侧髁突骨折行单侧手术的患者。排除标准为头部骨折、双侧髁突骨折双侧手术计划、腮腺区既往手术史、现有触及髁突的切口、术前 FN 无力迹象、或腮腺手术史。
预测变量是手术入路，受试者随机分配至 TMAP 和 TP。
主要结局变量是采用 House-Brackmann 量表和肌电图（EMG）评估术后 FN 功能，以记录神经功能的任何细微弱点。FN 功能在术后 3 个时间间隔（1 周[T1]、1 个月[T2]和 3 个月[T3]）进行记录。研究的次要结局是手术时间和任何其他并发症的记录。
年龄、性别、根据 Loukata 等人的分类，髁突骨折分为髁突颈或基底部骨折的骨折模式。任何与下颌骨相关的骨折，描述解剖部位为正中联合和颏旁（前下颌骨）、体部、对侧髁突或 1 处以上相关骨折的情况。同样，也记录了是否存在任何相关的面中部骨折，以表明研究参与者在各个方面都具有同质性。
分析统计包括卡方检验、t 检验和重复测量方差分析，然后进行事后检验，以比较两种手术入路（TP 与 TMAP）对面部肌肉（包括额肌、眼肌和颊肌）的 EMG 数据（平均功率和平均幅度），不同时间间隔（T0、T1、T2、T3）。还对每组患者进行了分析，以检查在随访期间是否发生神经恢复。显著性水平设定为 P<.05。
研究样本由 22 例患者组成，TMAP 组平均年龄为 32.82±11.21 岁，TP 组为 27.82±8.54 岁（P=.26）；TMAP 和 TP 组分别为 81.8%和 90.9%的男性优势（P=.53）。通过 House-Brackmann 量表评估的 FN 缺损，TP 组在 T1 时为 54%（T1），T2 时为 36.4%（T2），T3 时为 9.1%（T3），TMAP 组在 T1 时为 27%（T1），T2 时为 9%（T2），T3 时为 0%（T3）；然而，结果无统计学意义（P=.31）。在表面 EMG 评估中，TMAP 组额肌的平均功率在 T3 时显著较高（105.03±9.7 与 89.56±10；95%置信区间为-24.28 至-6.65，P 值=0.002）。TP 方法更快，平均暴露时间为 9.9 分钟。
结果表明，两种方法均可获得相似的长期结果，TMAP 组额肌活动更好。
