Acupuncture and vitamin B12 injection for Bell's palsy: no high-quality evidence exists

To assess the efficacy of acupuncture combined with vitamin B12 acupoint injection versus acupuncture alone to reduce incomplete recovery in patients with Bell's palsy.

A computer-based online retrieval of Medline, Web of Science, CNKI, CBM databases until April 2014 was performed for relevant trials, using the key words "Bell's palsy or idiopathic facial palsy or facial palsy" and "acupuncture or vitamin B12 or methylcobalamin".

All randomized controlled trials that compared acupuncture with acupuncture combined with vitamin B12 in patients with Bell's palsy were included in the meta-analysis. The initial treatment lasted for at least 4 weeks. The outcomes of incomplete facial recovery were monitored. The scoring index varied and the definition of healing was consistent. The combined effect size was calculated by using relative risk (RR) with 95% confidence interval (CI) using the fixed effect model of Review Manager.

Incomplete recovery rates were chosen as the primary outcome.

Five studies involving 344 patients were included in the final analysis. Results showed that the incomplete recovery rate of Bell's palsy patients was 44.50% in the acupuncture combined with vitamin B12 group but 62.57% in the acupuncture alone group. The major acupoints were Taiyang (EX-HN5), Jiache (ST6), Dicang (ST4) and Sibai (ST2). The combined effect size showed that acupuncture combined with vitamin B12 was better than acupuncture alone for the treatment of Bell's palsy (RR = 0.71, 95%CI: 0.58-0.87; P = 0.001), this result held true when 8 patients lost to follow up in one study were included into the analyses (RR = 0.70, 95%CI: 0.58-0.86; P = 0.0005). In the subgroup analyses, the therapeutic effect in patients of the electroacupuncture subgroup was better than in the non-electroacupuncture subgroup (P = 0.024). There was no significant difference in the incomplete recovery rate by subgroup analysis on drug types and treatment period. Most of the included studies were moderate or low quality, and bias existed.

In patients with Bell's palsy, acupuncture combined with vitamin B12 can reduce the risk of incomplete recovery compared with acupuncture alone in our meta-analysis. Because of study bias and methodological limitations, this conclusion is uncertain and the clinical application of acupuncture combined with vitamin B12 requires further exploration.