Patterns and predictive factors of hearing loss following microvascular decompression for hemifacial spasm: a systematic review.

In 30 seconds

This systematic review and meta-analysis assessed the prevalence, patterns, and potential risk factors for hearing loss after microvascular decompression for hemifacial spasm. It included 11 studies involving 4,014 adults with objective preoperative and postoperative hearing assessments. The pooled prevalence of permanent postoperative hearing loss was 2.60% (95% confidence interval [CI]: 1.13%-5.87%), with substantial between-study heterogeneity (I 2 = 87.4%). Brainstem auditory evoked response changes and greater cerebellar retraction were identified as factors associated with hearing impairment, although evidence on compressing vessel type was insufficient for reliable analysis.

Key findings

• Pooled prevalence of permanent postoperative hearing loss was 2.60% (95% confidence interval [CI]: 1.13%-5.87%; I 2 = 87.4%).
• Prevalence was 5.29% in prospective studies and 1.97% in retrospective studies; the difference was not statistically significant.
• Changes in brainstem auditory evoked response wave V latency or amplitude consistently predicted hearing impairment across most studies.
• Greater depth, distance, and duration of cerebellar retraction were significantly associated with increased hearing-loss risk.

Why it matters

Hearing impairment is an important potential complication of microvascular decompression, and the pooled estimate provides a broad indication of its frequency. The substantial heterogeneity means that this estimate is imprecise. Associations with intraoperative auditory response changes and cerebellar retraction highlight potentially relevant factors for understanding and monitoring this complication.

What to keep in mind

The pooled estimate had substantial between-study heterogeneity (I 2 = 87.4%). Evidence on compressing vessel type was insufficient and inconsistently reported, preventing reliable meta-regression.