Intradetrusor Versus Suburothelial Onabotulinum Toxin A in Adults with Neurogenic and Non-neurogenic Overactive Bladder Syndrome: A Meta-Analysis

Purpose: This systematic review and meta-analysis aimed to compare the effectiveness and safety of submucosal injection of onabotulinum toxin A (OnabotA) with intradetrusor injection for overactive bladder syndrome (OAB). Methods: This systematic review is registered with PROSPERO (CRD42021237964). A licensed librarian surveyed Medline, EMBASE, Scopus, and Google Scholar databases to conduct a comprehensive search. Studies comparing suburothelial and intradetrusor techniques of OnabotA injection for OAB were included, along with clinical and urodynamic variables and complications. The studies were assessed for quality on the basis of Cochrane Collaboration guidelines and evaluated using statistical analysis via a random-effect model and I 2 statistic. Data extraction and analysis were conducted using Covidence systematic review platform and Review Manager software. Results: Six studies with 299 patients were included in the systematic review, with four reporting that suburothelial injection of OnabotA was as effective as intradetrusor injection and two reporting intradetrusor injection to be more effective. The meta-analysis found no significant difference between the suburothelial and intradetrusor groups for mean daily catheter or voiding frequency (mean difference: 2.12 [95% confidence interval (CI): -1.61, 5.84]) and the mean number of urgency/urge incontinence episodes (mean difference: 0.08 [95% CI: -1.42, 1.57]). However, a significant heterogeneity was found among the studies. Only the mean volume at first detrusor contraction showed a significant difference, being higher for suburothelial injection (mean difference: 33.39 [95% CI: 0.16, 66.63]). No significant difference was noted for mean compliance, mean bladder capacity, and mean maximum detrusor pressure. Urinary tract infections (UTIs) ( p = 0.24) and acute urinary retention ( p = 0.92) showed no significant difference between the two groups. The risk of bias varied among the studies. Conclusions: Suburothelial injection of OnabotA is as effective as intradetrusor injection in improving OAB symptoms, and it has similar complication rates. A higher mean volume of the first detrusor contraction was found in a urodynamic study with suburothelial injection.