Short-Term Efficacy of Sacral Neuromodulation on Cystometric Parameters in Patients With Detrusor Overactivity

This study aimed to describe the short-term efficacy of sacral neuromodulation (SNM) on cystometric parameters in a population of patients with overactive bladder (OAB) associated with detrusor overactivity (DO).

This is a multicenter retrospective study, conducted in three university hospital centers. All patients who underwent two-stage SNM to treat OAB associated with DO between 2016 and 2023 were eligible. Three-day bladder-diary, uroflowmetry, and cystometric parameters were collected at baseline and at the end of the test phase. The primary end point was the disappearance of DO on urodynamic study performed at the end of the test phase. Secondary end points included changes in cystometric parameters, including maximum cystometric capacity (MCC), volume at first sensation of bladder filling (FSBF), volume at first noninhibited detrusor contraction (NIDC), and maximum detrusor pressure (PDetMax). All end points were evaluated in the overall population and in the following subgroups: nonneurogenic and neurogenic populations, nonneurogenic and neurogenic populations with high-pressure DO (PDetMax >40 cmH₂O).

Among the 97 patients included, 68 (70.1%) were women, and 39 (40.2%) had an underlying neurologic disease. In the overall population, DO disappeared in 18 patients (18.6%), whereas significant increases were observed in the volume at FSBF (+39.5 mL; p = 0.0014) and in MCC (+33.9 mL; p = 0.0021). In the subgroup of patients reporting clinical success and who underwent implantable pulse generator implantation, DO disappeared in 17 patients (20.2%), and improvements in sensory parameters were even more marked (FSBF: +46.9 mL, p < 0.001; MCC: +44.7 mL, p < 0.001). No significant change in PDetMax was observed in either group.

Our study showed that SNM completely eliminated DO in only 18.6% of cases. It also seemed more effective on sensory cystometric parameters (FSBF, MCC) than on motor cystometric parameters (NIDC, PDetMax).