下颌角磨削术中离断咬肌神经的临床研究

Clinic Study on Angle -grinding Ostectomy with Abscising Masseter Nerve for Prominent Mandibular Angle

目的：通过观察下颌角磨削术中咬肌神经离断后咬肌厚度的变化,探讨该手术的安全性及可行性.方法：对下颌角宽大畸形伴咬肌肥大18例患者,在局麻下采用下颌角磨削去骨矫治,术中采取口内切口,先作下颌骨的磨削,成形后再于咬肌与下颌支之间的咬肌间隙内,分离出咬肌神经的总干,并于下颌切迹下方0.5 cm处离断神经主干.采用高频浅表超声成像技术,分别在治疗前、治疗后每隔4～8周,放松及用力咬合状态下测量双侧咬肌厚度.结果：本组18例切口均一期愈合.术后均获随访1～6个月,无颈、唇部感觉麻木,无张口困难,咀嚼功能正常,下颌角部所形成的曲线优美圆滑、形态自然.在两种颌位状态下,治疗后24周双侧咬肌厚度均明显小于治疗前,差异有统计学意义（P＜0.05）.咬合状态下咬肌厚度缩小程度较松弛状态改善更为明显（P＜0.05）.结论：下颌角磨削去骨后离断咬肌神经主干操作安全,肥大的咬肌会出现明显萎缩,对咬肌肥大的患者可获得很好的临床疗效.

Objective：To explore the safety and feasibility of the angle - grinding ostectomy with abscising masseter nerve for the treatment of the enlarged mandibular angle by observing the changes of the masseter muscle. Methods：Angle -grinding ostectomy was performed for 18 patients through intraoral incision under local anaesthsia. Through this incision, masseter nerve was anatomied among the masseteric space and the nerve stem was abscised 0.5cm distance below the mandibular incisure. The thickness of masseter was bilaterally measured under both resting and maximal contracted positions by high - frequency superficial ultrasonic imaging preoperatively and every 4 -8 weeks postoperatively. Results：All patients were healed primarily. During the 1 - 6 months follow - up, no patients experienced numbness on the necks and lips, difficulty in opening mouth was not found, all cases had fine masticatory function. Curves of mandibular angle were smooth and natural. The mean thickness of masseter muscle atrophied markedly than that of preoperation （ P 〈 0.05 ）. Thickness of masseter muscle under the lnaximal contracted position was greatly decreased compared with the resting position （P 〈 0.05 ）. Conclusions：The masseter muscle becomes atrophy permanently after the angle -grinding ostectomy with abscising masseter nerve. This method is reliable and stable in clinic use.