RESUMEN
Background Microvascular decompression (MVD) utilizes brainstem auditory evoked potential (BAEP) intraoperative monitoring to reduce the risk of iatrogenic hearing loss. Studies report varying efficacy and hearing loss rates during MVD with intraoperative monitoring. Objectives This study aims to perform a comprehensive review and study of diagnostic accuracy of BAEPs during MVD to predict hearing loss in studies published from January 1984 to December 2013. Methods The PubMed/MEDLINE and World Science databases were searched. Studies performed MVD for trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia or geniculate neuralgia and monitored intraoperative BAEPs to prevent hearing loss. Retrospectively, BAEP parameters were compared with postoperative hearing. The diagnostic accuracy of significant change in BAEPs, which includes loss of response, was tested using summary receiver operative curve and diagnostic odds ratio (DOR). Results A total of 13 studies were included in the analysis with a total of 2,540 cases. Loss of response pooled sensitivity, specificity, and DOR with 95% confidence interval being 74% (60-84%), 98% (88-100%), and 69.3 (18.2-263%), respectively. The similar significant change results were 88% (77-94%), 63% (40-81%), and 9.1 (3.9-21.6%). Conclusion Patients with hearing loss after MVD are more likely to have shown loss of BAEP responses intraoperatively. Loss of responses has high specificity in evaluating hearing loss. Patients undergoing MVD should have BAEP monitoring to prevent hearing loss.
RESUMEN
OBJECTIVE: The primary aim of the study was to assess the sensitivity and specificity of intraoperative monitoring in predicting postoperative hearing loss during microvascular decompression (MVD). METHODS: The study was designed as an examination of the diagnostic accuracy of brainstem evoked potentials compared with reference standard for nonserviceable hearing loss (Class C/D), which is a change of more than 50 dB on pure tone threshold, and change of speech discrimination score of more than 50. All patients underwent surgery and audiograms at a University of Pittsburgh Medical Center facility in the study period 2005-2012. All participants received a pre- and postaudiogram within 90 days before or after the operation. During the operation, participants received intraoperative monitoring with a supervising physician. A total of 238 patients were selected. Brainstem auditory evoked potentials (BAEPs) were indexed into categories of change based on their maximum change and response at the end of surgery. Differences in hearing outcome by BAEP change were analyzed. RESULTS: Age and sex did not affect outcomes. Patient outcome was affected by condition. The BAEP categories significant changes, transient loss, and persistent loss show a sensitivity/specificity of 0.905/0.701, 0.667/0.903, and 0.429/0.972, respectively. The receiver operating characteristic curve has an area under the curve of 0.870 with a 95% confidence interval of 0.783 to 0.957. CONCLUSIONS: Loss of wave V during MVD is a specific indicator of postoperative hearing loss. The current alarm criteria used to warn the surgeon is a sensitive indicator of impending postoperative hearing loss. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that in patients undergoing MVD, intraoperative BAEPs accurately identifies those who will have postoperative hearing loss.