Management of the small acoustic neuroma: a decision analysis.

Imaging techniques such as magnetic resonance imaging (MRI) with gadolinium may detect small acoustic neuromas before significant symptoms have developed. In this situation, the patient and surgeon may question whether the tumor requires treatment, especially if the tumor was discovered incidentally. A computerized clinical decision analysis was undertaken to model the decision to observe such tumors or proceed to immediate surgery. The decision tree was constructed with flexibility to account for tumor size, hearing level, and other critical variables such as the individual's aversion to unilateral hearing loss and facial paralysis. Unless life expectancy is short, the analysis suggests that surgery at the time of diagnosis is appropriate, assuming that growth of the tumor is anticipated. Variations in surgical proficiency and patient risk aversion within expected ranges do not influence the decision to operate. The most critical variable appears to be the probability that the tumor will remain stable in size. This finding suggests that better data regarding the growth rate of small acoustic neuromas is needed.