The effect of onabotulinumtoxinA according to site of injection in patients with overactive bladder: a systematic review and meta-analysis

This study assessed the efficacy and safety of onabotulinumtoxinA according to injection site for treatment of overactive bladder. A systematic literature review located randomized controlled trials of onabotulinumtoxinA treatment for neurogenic detrusor overactive bladder and idiopathic overactive bladder in adults. We searched MEDLINE, EMBASE, and the Cochrane Controlled Trials Register using the Ovid platform. Meta-analysis was based on Cochrane Review Methods. Eight studies (419 participants) were included. Trigone-including injection demonstrated a significant improvement in symptom score (SMD = − 0.53, 95% CI − 1.04 to − 0.02, P = 0.04, I 2 = 78%), higher complete dryness rates (OR = 2.19 patients, 95% CI 1.32–3.63, P = 0.002, I 2 = 41%), and lower frequency of incontinence episodes (WMD = − 0.85 per day, 95% CI − 1.55 to − 0.16, P = 0.02, I 2 = 87%) in patients. Comparing trigone-including injection to trigone-sparing injection, lower detrusor pressure (WMD = − 2.55 cm H2O, 95% CI − 4.16 to − 0.95, P = 0.002, I 2 = 0%) and higher volume at first desire to void (WMD = 17.54 ml, 95% CI 1.00–34.07, P = 0.04, I 2 = 0%) were observed with trigone-including injection. Between intradetrusor and suburothelial injection sites, there were no differences in efficacy or safety regarding the incidence of vesicoureteral reflux, hematuria, general weakness, bladder discomfort, large post-void residual, and urinary tract infection. Trigone-including onabotulinumtoxinA injection has superior efficacy to trigone-sparing injection without increased complications. The depth of injection does not influence the efficacy or safety of onabotulinumtoxinA.