Clinical and financial audit of diagnostic protocols for lesions of the cerebellopontine angle.

OBJECTIVE To assess the diagnostic efficiency and costs of protocols used for investigating patients with suspected lesions of the cerebellopontine angle. DESIGN Prospective evaluation of tests of auditory brain stem responses and acoustic reflex thresholds, electronystagmography, and calorics. Positive test results were confirmed or refuted by high resolution computed tomography with intravenous enhancement. SETTING Single general otolaryngology clinic in a teaching hospital. PATIENTS 270 consecutive patients with sensorineural hearing loss requiring investigation to exclude a lesion of the cerebellopontine angle. MAIN OUTCOME MEASURES Estimated costs of various diagnostic protocols and performance in detecting tumours of the cerebellopontine angle. RESULTS Protocols including tests of auditory brain stem responses and acoustic reflex thresholds as sifting tests before computed tomography were clinically acceptable and presented considerable savings over the use of computed tomography in all patients (74,000 pounds or 84,000 pounds v 122,000 pounds). The use of electronystagmography and calorics could not be justified on clinical or financial grounds. CONCLUSIONS Audiological tests of auditory brain stem responses and acoustic reflex thresholds followed by computed tomography constitute the most cost effective protocol for determining suspected lesions of the cerebellopontine angle. IMPLICATIONS The cost effectiveness of diagnostic protocols should be evaluated throughout the health service.