[Keyhole microsurgery for acoustic neurinomas through suboccipital retrosigmoid sinus approach]

Acoustic neurinomas is one of the most common benign tumor in central nervous system, the main treatment is surgical resection. This study is to explore keyhole surgery with suboccipital retrosigmoid sinus approach for acoustic tumor resection and discuss how to improve the surgical skill and effect.

Thirteen cases of acoustic neurinomas from Sept. 2000 to Dec. 2001 in our department were operated using keyhole craniotomy technique through unilateral modified suboccipital retrosigmoid approach with "[symbol: see text]" incision. All patient underwent suboccipital craniotomy in order to maintain anatomical replacement, and the tumors (2.0-4.4 cm in diameter) were removed under microscope.

Tumors were completed resected in 11 cases, subtotally removed in 2 cases. Eleven patients had obtained anatomic preservation of the facial nerves. Complete follow-up information was obtained in all patients for a period of 3-15 months after operation. House-Brackmann Score in 8 case were Grade I-II, 4 cases Grade III-IV, one case Grade V. Grades I and II facial nerve function were maintained in 61.5% of cases, measurable hearing was preserved in 53.8% of cases(7 cases), and 38.5% of cases maintained serviceable hearing. No severe permanent operative complications were found and no surgical mortality occurred.

Microsurgery with keyhole craniotomy is a safe and effective method for treatment of patients with small and medium-size acoustic neuromas. The advantages of keyhole suboccipital craniotomy are anatomical replacement, less postoperative complications, and beneficial to patient's mental health.