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

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