A pilot prospective study to evaluate whether the bladder morphology in cystography and/or urodynamic may help predict the response to botulinum toxin a injection in neurogenic bladder refractory to anticholinergics

BACKGROUND We have observed different clinical responses to botulinum toxin A (BTX-A) in patients who had similar urodynamic parameters before the procedure. Furthermore, some bladders evaluated by cystography and cystoscopy during the procedure had different characteristics that could influence the outcome of the treatment. The aim of this study was to assess whether cystography and urodynamic parameters could help predict which patients with neurogenic detrusor overactivity (NDO) refractory to anticholinergics respond better to treatment with injection of BTX-A. METHODS In total, 34 patients with spinal cord injury were prospectively evaluated. All patients emptied their bladder by clean intermittent catheterization (CIC) and had incontinence and NDO, despite using 40 mg or more of intravesical oxybutynin and undergoing detrusor injection of BTX-A (300 IU). Pretreatment evaluation included urodynamic, and cystography. Follow-up consisted of urodynamic and ambulatory visits four months after treatment. The cystography parameters used were bladder shape, capacity and presence of diverticula. Urodynamic parameters used for assessment were maximum cystometric capacity (MCC), maximum detrusor pressure (MDP), compliance and reflex volume (RV). RESULTS After injection of BTX-A, 70% of the patients had success, with 4 months or more of continence. Before the treatment, there were significant differences in most urodynamic parameters between those who responded successfully compared to those who did not. Patients who responded successfully had greater MCC (p = 0.019), higher RV (p = 0.041), and greater compliance (p = 0.043). There was no significant difference in the MDP (0.691). The cystography parameters were not significantly different between these groups bladder shape (p = 0.271), capacity (p > 0.720) and presence of diverticula (p > 0.999). Statistical analyses were performed using SPSS (version 20.0) and included Student's t-test for two paired samples and Fisher's exact test, with a significance threshold of 0.05. CONCLUSIONS This study suggests that the cystography parameters evaluated cannot be used to help predict the response to injection of BTX-A in the treatment of refractory NDO. However, the urodynamic parameters were significantly different in patients who responded to the treatment, with the exception of the MDP.