The operative learning curve for vestibular schwannoma excision via the retrosigmoid approach.

The results of 127 operations for vestibular schwannomata via the retrosigmoid approach performed by a single surgeon over a 24-year period are examined. Facial nerve preservation and function, morbidity and mortality were recorded prospectively for three consecutive 8-year periods to assess the effect of increasing surgical experience on outcome. Rates of facial nerve preservation and good function (House grade I & II) improved over the study period. This reached statistical significance for medium-sized tumours, indicating that the effect was independent of tumour size, whose distribution varied through the series. Improvements occurred independently in the ability to preserve the nerve and its function. Analysis of the percentage of good facial nerve outcomes achieved over time indicated that the improvements occurred mainly between the 40th and 100th cases. Overall mortality was 3% and there were no deaths in the final time period. The implications of these findings for patient care and surgical training are discussed.