Analysis of the Correlation Between the Clinical Effect of Sacral Neuromodulation and Patient Age: A Retrospective Multicenter Study in China

Preliminary analysis of stimulation parameters for sacral neuromodulation in different indications: a multicenter retrospective cohort study from China

BACKGROUND

Sacral neuromodulation (SNM) is an effective approach for treating lower urinary tract dysfunction (LUTD), and stimulation programming is essential for successful treatment. However, research on SNM programming for various indications is limited. Thus, the authors aimed to determine whether there were differences in the stimulation parameters for different SNM indications and the appropriate programming recommendations.

MATERIALS AND METHODS

Clinical data were retrospectively collected from patients with LUTD who underwent SNM and completed internal pulse generator implantation. The parameters with the highest patient satisfaction or the most symptom improvement during the test period were considered optimal and used to set the programming after internal pulse generator implantation.

RESULTS

After screening, 282 patients were enrolled and categorized into four groups based on the following indications: refractory overactive bladder (OAB) ( n =61), neurogenic lower urinary tract dysfunction (nLUTD) ( n =162), interstitial cystitis/painful bladder syndrome (IC/BPS) ( n =24), and idiopathic nonobstructive urinary retention (NOUR) ( n =35). When analyzing the optimal stimulus parameters, disparities in the stimulation amplitude and pulse frequency were noted among the four groups. The stimulation amplitude in the nLUTD group was higher than that in the idiopathic NOUR group ( P =0.013). Differences in pulse frequency were observed between the refractory OAB and nLUTD groups ( P <0.001) and between the refractory OAB and idiopathic NOUR groups ( P =0.001). No differences in the electrode configuration or pulse width settings existed among the four groups.

CONCLUSIONS

The stimulation parameters for SNM varied among the different indications. For the initial programming of stage I, most patients are recommended to start with stimulation amplitudes below 2 V, although patients with nLUTD may benefit from higher amplitudes. A standard pulse width of 210 μs is recommended for all patients. However, for individuals experiencing nLUTD or idiopathic NOUR, the pulse frequency can begin above the standard 14 Hz but not exceed 50 Hz.

Remote programming in stage I sacral neuromodulation: a multicentre prospective feasibility study

OBJECTIVE

Sacral neuromodulation (SNM) has emerged as an effective therapy for refractory lower urinary tract dysfunction (LUTD). Remote programming holds promise in addressing the time and economic burdens associated with outpatient programming, especially for patients in the observation period following Stage I implant surgery (where the lead is implanted first without the pulse generator). The study aimed to explore the effectiveness and patient satisfaction of remote programming for Stage I SNM patients, and analyze the benefits patients gain from remote programming.

METHODS

This prospective study was conducted at multiple high-level clinical SNM centres in China. Patients requiring SNM implantation were enroled and divided into two groups based on patient preference: remote programming (RP) group and outpatient control (OC) group. Patient attitudes toward RP were assessed through questionnaires, and the degree of symptom improvement was compared between the two groups to explore the usability of RP.

RESULTS

A total of 63 participants from 6 centres were included in the study, with 32 belonging to the RP group. The remote programming system presents a high level of usability (98%) and willingness (satisfaction rate: 96.83%) in result of questionnaire. RP showed a significant advantage in improving patients' score of ICSI/ICPI (medianΔICSI/ICPI RP vs. OC= -13.50 vs -2, P =0.015). And slightly ameliorate urinary symptoms such as pain (medianΔVAS RP vs. OC= -1 vs 0, P = 0.164) and urgency (medianΔOBASS -2.5 vs. -1, P = 0.,229), but the difference was not statistically significant. RP did not significantly impact the quality of life of patients ( P =0.113), so do the rate of phase-two conversion ( P = 0.926) or programming parameters.

CONCLUSION

To the best of our knowledge, the presented study is the first multicenter research focusing on the remote programming of Stage I SNM patients. Through the clinical implementation and patient feedback, we demonstrate that remote programming is not inferior to in-person programming in terms of success rate, effectiveness, safety, and patient satisfaction.

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.

Sacral neuromodulation remote programming in patients with refractory lower urinary tract dysfunction: China’s experience during the COVID-19 pandemic

Objectives

Sacral neuromodulation is an effective, minimally invasive treatment for refractory lower urinary tract dysfunction. However, regular postoperative programming is crucial for the maintenance of the curative effects of electronic sacral stimulator devices. The outbreak of coronavirus disease 2019 (COVID-19) limited the ability of practitioners to perform traditional face-to-face programming of these stimulators. Therefore, this study aimed to evaluate the application of remote programming technology for sacral neuromodulation during the COVID-19 pandemic in China.

Materials and methods

We retrospectively collected data including baseline and programming information of all patients with lower urinary tract dysfunction who underwent sacral neuromodulation remote programming in China after the outbreak of COVID-19 (i.e., December 2019). The patients also completed a self-designed telephone questionnaire on the subject.

Results

A total of 51 patients from 16 centers were included. They underwent 180 total remote programming visits, and 118, 2, 25, and 54 voltage, current, pulse width, and frequency adjustments, respectively, were performed. Additionally, remote switching on and off was performed 8 times; impedance test, 54 times; and stimulation contact replacement, 25 times. The demand for remote programming was the highest during the first 6 months of sacral neuromodulation (average, 2.39 times per person). In total, 36 out of the 51 patients completed the questionnaire survey. Of these, all indicated that they chose remote programming to minimize unnecessary travel because they had been affected by COVID-19. The questionnaire also showed that remote programming could reduce the number of patient visits to the hospital, save time, reduce financial costs, and would be easy for patients to master. All surveyed patients indicated that they were satisfied with remote programming and were willing to recommend it to other patients.

Conclusion

Remote programming for sacral neuromodulation is feasible, effective, safe, and highly recommended by patients with refractory lower urinary tract dysfunction. Remote programming technology has great development and application potential in the post-pandemic era.

Sacral neuromodulation for overactive bladder using the InterStim and BetterStim systems

This study aimed to evaluate differences in the clinical outcomes of different sacral neuromodulation systems (InterStim and BetterStim) used in the treatment of overactive bladder. Data from a previously established database of sacral neuromodulation in China (the InterStim system) and a 2020 clinical trial of the BetterStim system were screened. Patients with overactive bladder undergoing stage II implanted pulse generator implantation were selected for analysis and divided into InterStim and BetterStim system groups. Voiding diaries and subjective scores obtained preoperatively, after stage I tined-lead implantation (experience period), and after stage II implanted pulse generator implantation were compared between the two groups. This study included 113 patients with overactive bladder (43, InterStim system group; 70, BetterStim system group). Voiding diaries and subjective scores significantly improved in both the InterStim and BetterStim system groups over the treatment period. Specifically, the urination frequency (all P < 0.001), average voiding volume (all P < 0.001), and average urinary leakage (InterStim, P < 0.05; BetterStim, P < 0.01) in both groups significantly improved at different periods during treatment. At the same time, the urgency perception scale (P < 0.001) and OAB-related quality of life score (InterStim, P < 0.05; BetterStim, P < 0.01) also significantly improved. There was no significant difference in urination frequency at baseline between the two groups (P = 0.169). Urination frequency was significantly higher in the BetterStim system group than in the InterStim group during the experience period and at follow-up (P = 0.031, P = 0.006). There was no significant difference in the number of urinary leakages between the different systems at baseline (P = 0.662), although this was higher in the InterStim system group during the experience period (P = 0.016), and the difference disappeared at the last follow-up (P = 0.565). There were significant differences in baseline urgency perception scale (P = 0.001) and OAB-related quality of life score (P < 0.001) between the two groups; however, these differences were not maintained at follow-up (P = 0.81, P = 0.479). Both sacral neuromodulation systems are safe and effective in treating overactive bladder. The InterStim system may be more beneficial for patients with dry overactive bladder. Satisfactory outcomes may be achieved with the BetterStim system in patients with wet overactive bladder. However, further studies are required to confirm this finding.

Bilateral electrical pudendal nerve stimulation as additional therapy for lower urinary tract dysfunction when stage II sacral neuromodulator fails: a case report

Background

Sacral neuromodulation (SNM) has become an effective therapy for patients with lower urinary tract dysfunction (LUTD) who do not respond to conservative treatment. However, an effective treatment strategy for patients who fail SNM has not yet been identified. An option for LUTD is needed when the clinical response to the SNM diminishes.

Case presentation

A 51-year-old Chinese man presented to an outpatient clinic complaining of difficulty in urination for > 3 years. The patient also complained of urinary frequency and urgency, accompanied by perineal discomfort. He was diagnosed with LUTD based on his symptoms and previous examinations. The patient underwent sacral neuromodulation with a permanent implantable pulse generator (IPG) (provided free of charge by Chengnuo Medical Technology Co., Ltd.; General Stim, Hangzhou, China) in the left buttock, as he participated in the company’s clinical trial to test the long-term effects of IPG. He reported loss of efficacy of the device 3 months after the implantation. We performed bilateral electrical pudendal nerve stimulation (EPNS) therapy for him. After 2 weeks of treatment, he began to report smooth voiding within 2 h after EPNS, and a moderate improvement in urinary frequency, urgency, and perineal discomfort. After 4 weeks of EPNS, the patient reported > 50% improvement in his urination, evaluated with the short form of the International Consultation on Incontinence Questionnaire for Male Lower Urinary Tract Symptoms. He reported smooth voiding, moderate improvements in urinary frequency and urgency, and the disappearance of the perineal discomfort. He also reported improved sleep and erections. The patient was discharged after 8 weeks of EPNS treatment.

Conclusion

EPNS could be an option as an additional therapy for patients with LUTD who have failed SNM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-021-00808-5.

Variable- versus constant-frequency sacral neuromodulation in black-zone overactive bladder patients: a study protocol for a multicenter, prospective, randomized, blind, self-controlled trial

Background

The curative effect of sacral neuromodulation (SNM), used to treat overactive bladder (OAB) patients, is definite. However, some patients still have recurrent symptoms after SNM and unsatisfactory symptom improvement after repeated adjustments of the stimulation parameters combined with oral drugs. These are referred to as black-zone OAB patients. The described SNM is the standard method, which involves a constant-frequency stimulation (CFS) of the patient's specific sacral nerve. A new treatment strategy, which combines the advantages of high-frequency and low-frequency stimulations to generate variable-frequency stimulation (VFS), has not yet undergone a formal randomized clinical trial. Therefore, we designed this clinical trial to evaluate the efficacy and safety of VFS-SNM and CFS-SNM in the treatment of black-zone OAB patients.

Methods

We designed a multicenter, prospective, randomized, blinded, self-controlled trial with a 12-week follow-up period. The trial randomly divides the enrolled patients into CFS-SNM and VFS-SNM groups. The main evaluation index is the comparative effectiveness of VFS-SNM and CFS-SNM at the last follow-up. The secondary evaluation indices include the change in the OAB symptom score, the quality of life (QOL) score, and the visual analog scale compared with the baseline period at each follow-up time point.

Discussion

Previous studies and our pre-experimental results suggest that black-zone OAB patients may benefit from VFS-SNM. Twelve weeks of VFS-SNM are effective in 40%, and the non-inferior cutoff value is 10% (80% power, 0.05 significance level, 20% loss to follow up). Thus, the calculated sample size is 37 cases each for CFS and VFS groups. The trial is expected to be carried out in 18 centers, but centers will be added or removed as appropriate depending on specific implementation conditions. Clinical researchers at each center will be responsible for screening qualified participants. This is the first randomized controlled trial to comprehensively evaluate the efficacy and safety of VFS-SNM in black-zone OAB patients, which will provide high-quality clinical evidence and may provide new clinical options for such patients.

Trial registration

Chinese Clinical Trial Registry: ChiCTR2000036677, registration date: 24 August 2020.

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

Overactive bladder (OAB) is a common urological disease, reducing patient quality of life (QoL). Sacral neuromodulation (SNM) is a treatment option used when conservative treatment is inadequate. However, constant frequency stimulation-SNM (CFS-SNM) may not be sufficiently effective in achieving targeted symptom reduction in some patients. For such black-zone patients, a different treatment strategy is needed. Variable frequency stimulation (VFS) has been used for deep-brain stimulation treatment in patients with Parkinson’s disease with positive outcomes. Accordingly, in this study, we hypothesized the promising outcomes of VFS-SNM in black-zone OAB patients. Here, we evaluated the efficacy and safety of VFS-SNM viz-a-viz CFS-SNM in a black-zone patient with refractory OAB whose frequent micturition symptoms were not relieved after undergoing traditional conservative treatment. A 50-year-old male patient was treated with CFS-SNM at our hospital in October 2016, but his symptoms recurred after administering multiple medications and program-controlled parameter adjustments. We then treated the patient with VFS-SNM in March 2020. A 2-week follow-up through telephonic interviews was conducted; the improvements in voiding symptoms were evaluated by calculating the OAB symptom score (OABSS) and OAB-related QoL (OAB-QoL) score. We observed that OABSS was significantly lower after VFS-SNM than after CFS-SNM. Further, we observed that VFS-SNM significantly improved daytime and nocturnal micturition frequency, as evident from the reduced OABSSs from after CFS-SNM to after VFS-SNM. The main reason for patient dissatisfaction after CFS-SNM was the increased average daily micturition frequency and urgency. VFS-SNM controlled the micturition frequency to within the patient’s acceptable range, significantly improving the patient’s QoL (40% improvement in OAB-QoL score). To the best of our knowledge, this is the first case report on the use of VFS-SNM with positive outcomes in a black-zone OAB patient, suggesting that VFS-SNM is not inferior to CFS-SNM in the treatment of black-zone patients.

Influence of patient sex on the effectiveness of sacral neuromodulation: A cohort study from China

BACKGROUND

Sacral neuromodulation (SNM) has been widely used to treat lower urinary tract dysfunction. Studies have shown a higher conversion rate among female patients than among male patients. However, the influence of gender on the clinical effectiveness of SNM remains unclear. We aimed to confirm whether patients of both genders show similar benefits after SNM treatment.

MATERIALS AND METHODS

Clinical data of patients with lower urinary tract symptoms associated with pelvic floor dysfunction (overactive bladder, neurogenic bladder, interstitial cystitis/painful bladder syndrome, idiopathic urinary retention) treated with SNM in 10 medical centres in China between January 2012 and December 2016 were retrospectively collected. The patients were classified by gender. Variations in objective (voiding diary) and subjective scores in the baseline, testing, and last follow-up periods were compared. Data were analysed using statistical measures.

RESULTS

The study included 203 patients (93 males, 110 females). There were no statistical differences in baseline information between the two groups, both groups showed improvement over time. Unsatisfactory improvement was observed in the quality of life and sexual life scores of both groups over the entire treatment period (all p＞0.05). Although there was a difference in the maximum voiding volume between the groups at baseline, no difference was observed at the last follow-up (p = 0.004, p = 0.044, p = 0.124), unlike in the average volume where a difference was noted at the last follow-up (p = 0.085, p = 0.964, p = 0.031). While there were no differences in quality of life, sexual life, or pelvic pain and urinary urgency frequency scores at baseline, a significant difference was observed at the last follow-up, and the degree of improvement was less among female patients (p = 0.836, p = 0.131, p = 0.015; p = 0.294, p = 0.265, p = 0.013; p = 0.299, p = 0.087, p = 0.015).

CONCLUSION

SNM treatment elicited a similar effect on patients of both gender; however, a significant difference was observed regarding patient satisfaction with the treatment. Further preoperative patient education, especially, for female patients with interstitial cystitis/painful bladder syndrome may improve patient satisfaction.