Minimally invasive treatment for acoustic neuromas by retrosigmoid transmeatus approach

Objective To explore surgical methods and techniques of minimally invasive microsurgical resection of acoustic neuroma, in order to improve the total resection rate of tumor and the protective rate of facial nerve. Methods Eight hundred and eighty-seven patients suffering from acoustic neuromas treated microsurgically by suboccipital retrosigmoid transmeatus approach were analyzed retrospectively between January 2000 and December 2017. Routine reexamination of enhanced MRI and assessment of facial nerve function were performed in 3 months after operation. Results Total resection of the tumor was achieved microsurgically in 841 cases, the total removal rate was 94.8%. The facial nerve was preserved anatomically in 832 cases during the operation, the facial nerve anatomic reservation rate was 93.7%. Fifty-five cases were not preserved in the anatomy, 16 of them received end to end anastomosis of facial nerve, and 3 cases underwent facial nerve grafting after operation. After 3 months of tumor resection, 695 cases (78.4%) of facial nerve function were restored to House-Brackmann (H-B) grade I to Ⅱ, 176 cases(19.8%) H-B grade III to Ⅳ and 16 cases (1.8%) H-B grade V. Conclusion Minimally invasive microsurgery for acoustic neuroma is helpful to improve the safety and surgical effect of tumor resection. Mastery of microsurgical skills is the key to the improvement of total tumor resection, facial nerve anatomy and function protection. Key words: Acoustic neuroma; Facial nerve; Electrophysiologic monitoring; Microsurgical technique