Preoperative urodynamic factors predicting outcome of botulinum toxin-A intradetrusor injection in children with neurogenic detrusor overactivity

Objective To investigate urodynamic (UD) parameters that predict outcome of intradetrusor botulinum toxin-A (BTX-A) injection in children with neurogenic detrusor overactivity (NDO), by reviewing clinical and UD data. Methods From January 2010 to March 2014, 56 cases of the first BTX-A intradetrusor injection were performed in pediatric patients with NDO. We excluded 19 cases based on these criteria: patient age <4 years, no preoperative UD study or postoperative outcome assessment, and simultaneous sphincter injection. Based on the Patient Global Impression of Improvement, patients were classified as responders or nonresponders. Results Thirty-seven cases were included finally. Mean number of pads used per day was significantly decreased after BTX-A injection (2.67 ± 1.46 vs 1.37 ± 1.15; P <.001). On postoperative UD study, maximum cystometric capacity and residual urine volume were significantly increased above baseline. Persistent NDO was only detected in 3 cases (8.1%). Regardless of UD improvements, 20 cases were responders, whereas 17 were nonresponders based on Patient Global Impression of Improvement. Preoperative bladder compliance was significantly lower in nonresponders (25.11 ± 32.59 vs 8.64 ± 6.52; P =.039). Open bladder neck (OBN) was seen in 9 cases and more likely occurred in nonresponders. Regression analysis revealed that poor bladder compliance (<10 mL/cm H₂O; odds ratio, 6.041; 95% confidence interval, 1.189-30.677; P = .030) and presence of OBN (odds ratio, 16.889; 95% confidence interval, 1.825-156.282; P = .031) were independent predictors of poor response after BTX-A injection. Conclusion Preoperative bladder compliance and OBN were important predictors of outcome after BTX-A intradetrusor injection. Thus, intradetrusor BTX-A injection should be considered in select patients to achieve optimal outcome.