Objective      To evaluate the significance of proper drilling strategies on the posterosuperior wall of internal auditory canal in acoustic neuroma surgery.       Methods      A total of 135 patients with acoustic neuroma undergoing surgery treatment in our department from January 2007 to September 2012 were enrolled in this study and retrospectively analyzed. Suboccipital retrosigmoid approach in lateral park beach position was used for all the patients. They were all under intraoperative nerve monitoring. High speed steel cutting drill was u

sed to remove the posterior wall of internal auditory canal during operation. At the beginning

high speed steel cutting drill was used to drill. And then

when the posterosuperior wall of internal auditory canal was partly drilled open

high speed diamond drill was used to finely strip. Posterior wall of internal auditory canal was drilled as the main part. The superior wall of internal auditory canal should be regarded as an important part when high jugular bulb was present.       Results      Among the 135 patients with acoustic neuroma (from T

3a

-T

4b

)

125 patients (92.6%) were treated with total resection

8 patients were treated with subtotal resection (5.9%)

and 2 patients were treated with partial resection (1.5%). The facial nerve was anatomically preserved in 126 cases of patients (93.3%). The assessment in half a year after operation showed that the facial nerve was functionally preserved for 82 cases of patients (60.7%) [according to the House-Brackmann (HB) facial nerve grading system

gradeⅠ-Ⅱ

14 cases (10.4%) and grade Ⅲ

68 cases (50.4%)

]

. There were 5 cases (5/135

3.7%) having leakage of cerebrospinal fluid

and among them

4 patients (3.0%)were recovered after expectant treatment

and 1 case (0.7%) was recovered after surgical repair. What’s more

7 cases (5.2%) was accompanied with dysphagia as well as cough

6 cases (4.4%)with ataxia

and 1 case (0.7%) dead.       Conclusion      Sufficient preoperative assessment and appropriate management of the posterosuperior wall of internal auditory canal are very important for total resection of the tumor and preservation of the facial nerve.