To assess the efficacy of sacral nerve modulation (SNM) in the treatment of neurogenic overactive bladder (nOAB) in patients with multiple sclerosis (MS).
This retrospective multicenter study was conducted across four university hospital centers. All MS patients that underwent a two-stage SNM to treat nOAB between 2013 and 2023 were considered eligible. The primary outcome was clinical efficacy, defined as the implantation of an implantable pulse generator (IPG), associated with a 50% or greater improvement in one or more of the troublesome urinary parameters compared to baseline, as assessed by a 3-day bladder diary. Secondary outcome included self-assessment of efficacy using the Patient Global Impression of Improvement (PGI-I) rating scale, the 3-day bladder diary parameters at baseline and at the end of the test phase, and the maintenance of efficacy within 3 years following IPG implantation -using the PGI-I rating scale.
A total of 33 patients were included, 27 (82%) being females. The median Expandable Disability Status Scale (EDSS) at the time of the test phase was 4.0 ［2.5; 3.5］. Most of the patients (66.7%) were under spontaneous micturition, while 30.3% performed clean intermittent self-catheterization (CISC) and one (3.0%) was under third-person catheterization. The IPG was implanted in 29 (87.9%) patients. On PGI-I rating scale, a score of ≧ 2 (indicating “much better” or “very much better”) was reported by 23 (69.7%) patients at the end of the test phase. The median daily micturition/CISC frequency significantly decreased from baseline (9.00 [7.00; 12.0]) to the end of the test phase (7.00 [6.00; 8.00]; p <0.001). Similarly, the median nocturnal micturition/CISC frequency significantly decreased from 2.50 [1.00; 3.75] to 1.00 [0; 2.00] (p < 0.01). Furthermore, the presence of diurnal urgency episodes reduced significantly (97% vs 54%; p< 0.01), as did the presence of urge urinary incontinence episodes (82% vs 18%, p< 0.001) at the end of the test phase. However, the presence of nocturnal urgency episodes decreased without reaching statistical significance (43% vs 8.3%, p = 0.077). Fourteen patients completed a 3-year follow-up after IPG implantation, with 2 (14.3%) considered lost-to follow-up. Among the remaining 12 patients, a PGI-I rating scale score ≧ 2 was maintained in 7 (58.3%).
In MS patients with nOAB, SNM appears to exhibit clinical efficacy comparable to that observed in the non-neurological population, albeit with a med-term loss of efficacy.
