Clinical Implication of Facial Nerve Decompression in Complete Bell's Palsy: A Systematic Review and Meta-Analysis

We compared the therapeutic efficacy of facial nerve decompression (FND) and conservative treatment in patients with Bell's palsy through a systematic review and meta-analysis. Primary database search was performed in PubMed, Medline, and Embase. After screening, 13 studies were assessed for their eligibility. Among them, seven studies employing either the House-Brackmann grading system (HBGS) or May's classification (modified HBGS) were selected for quantitative and qualitative analysis. Based on May's classification, the degree of recovery was classified into complete (HBGS I), fair (HBGS II-III), or failed (HBGS IV-VI) recovery. The outcomes were assessed between 6 and 12 months after surgery. The estimated pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using random effects model. Cohorts were comprised of patients who underwent FND (n=202, 53.0%) and conservative treatments (n=179, 47.0%). In pooled analysis, the rate of complete recovery was significantly higher in the FND group than in the control group (OR, 2.06; 95% CI, 1.22 to 3.48; P=0.007) showing neither heterogeneity nor publication bias. Meanwhile, the rates of fair recovery (OR, 0.71; 95% CI, 0.42 to 1.21; P=0.208) and failed recovery (OR, 0.60; 95% CI, 0.22 to 1.67; P=0.327) in the FND group were similar to that in the control group. In subgroup analyses, there was no significant difference in the OR according to the operation timing and surgical approach. FND can be a possible treatment option for patients with complete Bell's palsy, especially for complete recovery, which provide insights on decision-making and outcome prediction. However, FND should be determined carefully given the risk of small study effects and possible complications.