Variable frequency stimulation of sacral neuromodulation in black-zone overactive bladder patients: a case report

Efficacy and Safety of Sacral Neuromodulation by Converting Constant Frequency Stimulation Into Variable Frequency Stimulation in Patients With Detrusor Overactivity and Impaired Contractility: A Single-Center Prospective Study

OBJECTIVES

In patients with detrusor overactivity with impaired contractility (DOIC), it is difficult to relieve abnormal lower urinary tract symptoms during both storage and voiding using sacral neuromodulation (SNM) with constant frequency stimulation (CFS). We sought to evaluate the efficacy and safety of SNM using variable frequency stimulation (VFS) in patients with DOIC by comparing it with outcomes of SNM with CFS.

MATERIALS AND METHODS

Between September 2020 and May 2021, we prospectively enrolled 20 patients with DOIC, confirmed on urodynamic examination, and administered SNM with VFS. The patients were followed up and required to maintain voiding diaries and record scale scores of overactive bladder symptoms, psychology and quality of life, uroflowmetry, ultrasonic postvoid residual urine, and adverse events at baseline and during the CFS and VFS phases.

RESULTS

The average testing phase was 26.3 ± 4.1 days. Compared with baseline values, overactive bladder symptom, psychologic health questionnaire, and quality of life scores, in addition to voiding frequency, urgency incontinence frequency, daily catheterization volume of voiding diary, and ultrasonic postvoid residual (PVR) decreased significantly during both the CFS and VFS phases (p < 0.05). The average voided volume, functional bladder capacity, and maximum urine flow rate significantly increased during the CFS and VFS phases (p < 0.05). In the VFS phase, voiding frequency, urgency incontinence frequency, daily catheterization volume of voiding diary, and ultrasonic PVR further decreased (p < 0.05), whereas functional bladder capacity, maximum urine flow rate, quality of life score, overactive bladder symptom score, and psychologic health questionnaire score further improved compared with results obtained in the CFS phase (p < 0.05). In the VFS phase, the success rate of further improvement of symptoms was 85.0%, and no new complications were noted.

CONCLUSIONS

SNM that converts CFS into VFS may be an effective treatment option for patients with DOIC, exhibiting no increase in adverse events.

Intermediate-term results of a prospective, multicenter study on remote programming sacral neuromodulation for refractory overactive bladder

Background

To evaluate the efficacy and safety of a novel remote programming sacral neuromodulation (SNM) system (BetterStim system) in the treatment of patients with refractory overactive bladder (OAB) for 3 years.

Methods

A total of 8 centers in China enrolled 84 patients with OAB. Following test stimulation 70 patients underwent implantation using BetterStim. All patients returned for follow-up at 3 and 6 months postoperatively. After that, the visits were conducted by telephone. Outcomes of voiding diaries, the overactive bladder symptom score (OABSS), questionnaires regarding OAB-related quality of life (OAB-qol), and adverse events (AEs) were evaluated at each visit. The clinical therapeutic success was defined as ≥50% improvement from baseline in any of the voiding diary variables or average voids/day return to normal voiding (<8 voids/day). The analysis is a modified Completers analysis.

Results

At the 36-month follow-up, the success rate was 79% for overall OAB symptoms, 69% for urge urinary incontinence (UUI) and 42% for urgency frequency (UF). The average number of voids/day decreased from 29.2±14.9 at baseline to 17.6±11.2 at 3 years, the average volume/void increased from 94.7±54.2 to 151.4±80.8 mL, the urgency reduced from 3.0±1.4 to 1.8±1.7 (all P<0.001). For patients with urge incontinence, mean leaking episodes/day decreased from 8.1±7.6 at baseline to 2.1±3.5 at three years (P<0.05). The devices were explanted in 8 (11.4%) patients. There were no remote programming-related AEs or device-related serious AEs that occurred.

Conclusions

The Intermediate-term results demonstrated that BetterStim SNM system with remote programming is safe and effective for patients with refractory OAB.