Botulinum toxin for facial neuralgia

Data sources Medline via PubMed, the Web of Science and the Cochrane Library were searched until April 2014. Study selection Randomised controlled trials (RCTs) comparing the efficacy of botulinum toxin type A (BoTN-A) with placebo in patients with painful trigeminal (TN) and postherpetic neuralgia (PHN) reporting changes in pain intensity in patients aged 19 years and older available in English were included. Data extraction and synthesis Three authors independently assessed for inclusion, extracted standard data and assessed for risk of bias. The primary outcomes were baseline and post treatment intensity of pain and patients reporting pain relief of 50% or greater. For continuous outcomes the treatment effect was measured as mean differences with 95% confidence intervals (CIs). For dichotomous outcome of reduction of pain of 50% or more, relative risk (risk ratio) with 95% CIs was reported. Statistical heterogeneity was tested with Cochran's test for heterogeneity and quantified by the I2 statistic. Results were combined using random-effects model in the presence of statistical heterogeneity otherwise fixed effect model was used. Results Six studies were included. The effects of the interventions were presented in three meta-analyses. Mean difference in post treatment pain (six studies) pooled results showed a reduction of −3.009 in the VAS (95% CI −4.566 to −1.453 p<0.001) with the use of BoTN-A. Standardised difference in mean post treatment pain (six studies) was −0.918 (95% CI −1.197 to −0.639 p<0.001) in favor of BoTN-A. For the percentage of patients experiencing 50% pain reduction (three studies) absolute risk difference and relative risk were calculated (RR 2.892, 95% CI 1.726 to 4.848 p<0.001) in favour of the use of BoTN-A. Conclusions The authors concluded that there is moderate evidence regarding the efficacy of BoTN-A in treating patients with trigeminal neuralgia and postherpetic neuralgia.