面神经结构与功能可视化技术在大型听神经瘤手术中的初步应用

Preliminary application of structural and functional visualization of facial nerve in large vestibular schwannoma surgery

目的 术前应用磁共振弥散张量纤维束成像技术行面神经成像,术中联合面神经肌电图监测,实现面神经结构与功能的可视化,探讨其在大型听神经瘤手术中保护面神经的意义.方法 选取15例大型听神经瘤（内听道外最大径≥30 mm）病例,术前采用磁共振弥散张量纤维束成像技术显示肿瘤侧面神经,术中行面神经动态、主动刺激肌电图监测,并在术中验证术前面神经定位准确与否,术后定期随访评估面神经功能.结果 13例面神经可通过弥散张量纤维束成像技术显示,其中7例面神经位于肿瘤前中1/3,3例位于肿瘤前下1/3,2例位于肿瘤前上1/3,1例位于肿瘤下极,术前定位结果与术中所见吻合率为100％.11例肿瘤全切除,4例次全切除.术中面神经动态肌电图监测可提示面神经牵拉或挤压、定位面神经,主动刺激肌电图监测有助于确认可疑组织是否为面神经、证实面神经完整性.所有病例面神经均解剖保留.术后随访4 ～ 18个月,面神经功能House-Brackmann Ⅰ级8例,Ⅱ级6例,Ⅳ级1例.结论 通过面神经弥散张量纤维束成像和术中电生理监测等面神经结构和功能可视化技术,有助于术中定位和保护面神经,提高大型听神经瘤手术面神经的解剖和功能保留率.

Objective To obtain structural and functional visualization of facial nerve （FN）by preoperative identification with diffusion tensor tracking （DTT） and intraoperative electrophysical monitoring （IOM） and explore the effect of these techniques on preservation of facial nerve in large vestibular schwannoma （extrameatal diameter≥ 30 mm,VS） surgery.Methods Fifteen patients habouring large VS were adopted in this retrospective study.Structural and functional visualization of FN was conducted in each patient.Correlation of FN location between preoperative identification and intraoperative inspection was analysed.Postoperative FN function was evaluated in each patient periodically.Results FN was identified by DTT in 13 cases.Seven FNs located at the anterior middle third of the tumor,3 at the anterior inferior third,2 at the anterior superior third,and 1 at the inferior pole.The locations agreed to intraoperative findings and monitoring in all the 13 cases.Gross total resection was achived in 11 cases and subtotal in the other 4 cases.IOM was helpful to locate and protect the FN.All FNs were anatomically preserved.House-Brackmann grade Ⅰ of FN function was achieved in 8 cases,grade Ⅱ in 6,and grade Ⅳ in one.Conclusion Structural visualization by preoperative DTT and functional visualization by IOM of FN contribute to lacating and preserving FN in large VS surgery.