A Study On The Microsurgical Treatment And Techniques Of Facial Nerve Preservation For Large Acoustic Neuromas

Objective: To explore the surgical strategy and techniques of facial nerve preservation in the microsurgical treatment for large acoustic neuromas, so that to improve the therapeutic effects of this type of tumors.Methods: The data of 59 cases of large acoustic neuromas treated microsurgically by suboccipital retrosigmoid approach were analyzed and summarized retrospectively. Among them, the late 27 cases were treated with intraoperative facial nerve monitoring (IFNM group), the previous 32 cases were treated with no intraoperative nerve facial monitoring (NIFNM group).The results of the facial nerve preservation were compared between the two groups.Results: Total tumor resection was achieved in 54 of the 59 patients(91.5%), subtotal resection in 4(6.8%) and partial resection in 1(1.7%). No patient died. 25(92.6%) cases facial nerve were anatomically preserved in the IFNM group and 23(71.9%) cases in the NIFNM group. According to House-Brackmann(H-B) facial nerve grading system 6 months after operation : IFNM group: 20(74.1%) cases with H-B Grade I,II; 5(18.5%) cases with H-B grade III,IV; 2(7.4%) cases with H-B grade V,VI. NIFNM group: 14 (43.8%) cases with H-B Grade I,II; 8(25.0%) cases with H-B grade III,IV; 10 (31.2%) cases with H-B grade V,VI. Both of the anatomic and functional preservation(H-B I,II) rates of facial nerve in the IFNM group are higher than that of NIFNM group, The difference was significant(P<0.05) in the results of facial nerve preservation between the two groups.Conclusions: Learning the pathological anatomic relationships between the facial nerve and the tumor, skilled microsurgical technique and IFNM are very important for totally tumor resection and facial nerve preservation in the patients with large acoustic neuromas. The anatomic and functional preservation rates of facial nerve could be increased by using of IFNM. The prognosis is also could be improved .