ABSTRACT
Objective To evaluate the safety and efficacy of microsurgical resection of large acoustic neurinoma via the suboccipital retrosigmoid approach.Methods Forty-nine patients with large acoustic neurinoma(≥4 cm) underwent microsurgical resection through suboccipital retrosigmoid approach.The craniotomy was performed by way of an unilateral S-shaped suboccipital incision.With microsurgical techniques the outmost layer of the arachnoid membrane was preserved in order to avoid damaging to the surrounding vital structures.The tumor was resected intracapsularly from the superior pole and the internal auditory meatus was finally opened.The last pieces of tumor were removed by sharp dissection from the facial nerve bidirectionally,and were resected cautiously in a piecemeal fashion.Results Of the 49 patients,45 patients(92%) received a total resection of the tumors,and 4 patients(8%) subtotal resection.No patients died.The facial nerve was preserved anatomically in 42 patients(86%) and functionally in 36 patients(73%).The acoustic nerve was preserved anatomically in 7 patients(14%) and functionally in 3 patients(6%).One patient experienced a postoperative haematoma,and a re-operation was required.No recurrence was seen in 37 patients during a follow-up for 6 months ～ 5 years(mean,2.8 years).These patients had recovered for normal work and daily activities.Conclusions Microsurgical operation through suboccipital retrosigmoid approach is a favorable treatment for large acoustic neurinomas.The procedure can improve the rate of total resection,decrease the morbidity and mortality,and effectively protect the function of the acoustic and facial nerves.