Abstract: Objective　To investigate the distribution of the facial nerve in acoustic neuroma using preoperative diffusion tensor imaging（DTI） combined with intraoperative exploration of the positional relationship between the facial nerve and acoustic neuroma. Methods　A total of 45 patients with acoustic neuroma who were treated in Ganzhou Hospital Affiliated Nanchang University between January 2014 and July 2017 were selected.The positional relationship between the facial nerve and the tumors was detected through DTI. The position of the facial nerve was verified and monitored by electrophysiology during the operation. The House-Brackmann（H-B） facial nerve grading scale was used to assess patient facial nerve function before surgery and within 2 weeks after surgery. Results　Among the patients，there were 42 patients whose facial nerve could be displayed by DTI；in 39 patients（92.9%），the facial nerve position detected by DTI was consistent with intraoperative electrophysiology monitoring and anatomical marks. The facial nerves of these patients were all located on the ventral side of the tumor；among them，17 cases（43.6%） were located in the middle third of the tumor，9 cases（23.1%） were located in the lower third of the tumor，8 cases（20.5%） were located in the upper third of the tumor，3 cases（7.7%） were located in the lower pole of the tumor，and 2 cases（5.1%） were located in the upper pole of the tumor. The facial nerve was anatomically preserved in 41 cases（91.1%）. The facial nerve was not detected in 2 cases（4.4%） during surgery，and facial nerve injury occurred in 2 cases（4.4%），owing to inconsistencies in the facial nerve position and the position detected by preoperative DTI. The H-B facial nerve grading scale within 2 weeks after surgery was as follows：25 cases of grade Ⅰ-Ⅱ（55.6%），15 cases of grade Ⅲ-Ⅳ（33.3%） and 5 cases of grade Ⅴ-Ⅵ（11.1%）. Forty-two cases（93.3%） had total tumor resection；1 case（2.2%） had residual tumor tissue in the auditory canal；2 cases（4.4%） had a small amount of tumor residue adjacent to the brain stem and adhering to the facial nerve；2 cases（4.4%） underwent bone flap removal after surgery，owing to cerebellar swelling；1 case（2.2%） died of postoperative bleeding at the operation site；and 1 case（2.2%） experienced hemiplegia due to a partial infaRCTs of the brainstem and was able to live independently after 3 months of rehabilitation. Conclusion　Preoperative facial nerve DTI can predict the position of the facial nerve. The position of the facial nerve in the cerebral cisternal side in acoustic neuroma is variable. Understanding the distribution of the facial nerve in acoustic neuroma can improve anatomical and functional preservation of the facial nerve.

Key words: Neuroma, acoustic；Facial nerve；Nerve distribution；Diffusion tensor imaging；Surgical procedures, operative

摘要： 目的　术前应用磁共振弥散张量纤维束成像技术（DTI）行面神经成像，结合术中面神经与听神经瘤的位置关系，探讨听神经瘤中面神经的分布规律。方法　选取2014年1月—2017年7月南昌大学附属赣州医院收治的听神经瘤患者45例，术前行面神经DTI显示肿瘤与面神经的关系，术中行神经电生理监测验证面神经的位置，术前、术后2周内采用House-Brackmann（H-B）面神经功能分级对患者进行面神经功能评定。结果　42例听神经瘤患者的面神经可通过DTI显示，术中通过神经电生理监测及解剖标识确定面神经位置与DTI相吻合者39例（92.9%），其面神经均位于肿瘤腹侧，其中，17例（43.6%）位于肿瘤中部1/3，9例（23.1%）位于肿瘤下部1/3，8例（20.5%）位于肿瘤上部1/3，3例（7.7%）位于肿瘤下极，2例（5.1%）位于肿瘤上极。41例（91.1%）面神经解剖保留，2例（4.4%）术中未发现面神经，2例（4.4%）术中面神经位置与术前DTI成像面神经位置不相符导致操作过程中神经损伤。术后2周内H-B面神经功能分级为Ⅰ~Ⅱ级25例（55.6%），Ⅲ~Ⅳ级15例（33.3%），Ⅴ~Ⅵ级5例（11.1%）。42例（93.3%）肿瘤全切除，1例（2.2%）内听道部分肿瘤残余，2例（4.4%）脑干及与面神经粘连少量残留，2例（4.4%）因小脑肿胀术后去除骨瓣，1例（2.2%）术后术区出血死亡，1例（2.2%）脑干部分梗死致一侧肢体偏瘫，康复治疗3个月后可自主生活。结论　术前面神经DTI可以预测面神经的位置，听神经瘤中脑池段面神经位置多变，掌握听神经瘤中面神经的分布规律可提高面神经的解剖及功能保留率。

关键词: 神经瘤, 听；面神经；神经分布；磁共振弥散张量纤维束成像技术；外科手术