Neurogenic detrusor overactivity (NDO) is treated with antimuscarinics as first-line treatment. For patients with contraindications or unresponsive, intradetrusor injections with botulinum toxin (BoNT) are a safe and effective but expensive option.
Our study evaluated whether adding solifenacin to the intradetrusor injection of BoNT A could boost the effect of BoNT in patients with NDO due to multiple sclerosis or spinal cord injury refractory to antimuscarinics alone and/or lead to less frequent injections.
We performed a prospective study on 49 patients assigned alternatively to group A, undergoing BoNT injections, and group B, adding solifenacin.
Measures and Outcomes:
We gathered data from urodynamic testing and questionnaire assessments before and 3 months after injections and reinjections. We analyzed 39 patients who achieved total continence and a minimum 24-month follow-up period.
After treatment, both groups had statistically significant improvement of overactive bladder questionnaire (OABq) score, post void residue (PVR), and peak detrusor pressure (Pdet). Reinjection was needed after a mean 8.2 months for group A and 11.7 months for group B. We analyzed the improvement rate of parameters compared between the 2 groups—group B had greater OABq score improvement (A = 17.25 ± 5.07, B = 20.44 ± 4.51, P = 0.0485), as well as for maximum bladder capacity (A = 11.05 ± 7.04 mL, B = 19.39 ± 6.43 mL, P = 0.0005); differences in Pdet change (A = 51.72 ± 16.57 cmH2O, B = 50.80 ± 16.33 cmH2O, P = 0.7635) and PVR change (A = 17.67 ± 12.63 mL, B = 12.30 ± 8.32 mL, P = 0.126) were not statistically significant.
Our study shows that adding solifenacin improves patient satisfaction, increases the interval between reinjections, thus lowering costs, and improves maximum bladder capacity. Pdet was kept in safe ranges, but no statistically significant conclusions could be drawn regarding Pdet and PVR decrease related to adding solifenacin. Although our study is limited by the small series of patients and lack of randomization and placebo control group, the BoNT–solifenacin combination could be considered in NDO in terms of cost-effectiveness. Further studies would be beneficial.