Sacral neuromodulation for treating the symptoms of overactive bladder syndrome and non-obstructive urinary retention: >10 years of clinical experience

Sacral neuromodulation in the management of non-obstructive urinary retention: Test phase and predictive factors

AIM

The aim of this study is to evaluate the success of the test phase of sacral neuromodulation in management of chronic non-obstructive urinary retention and the factors predictive of good response.

MATERIALS AND METHODS

This is a retrospective study carried out on a cohort of patients followed up in a tertiary University Hospital in France. Fifty-two patients with chronic non-obstructive urinary retention were included in this study. These patients were seen over the past 20 years, from the year 2000 to 2020. The initial evaluation of patients included a summary of medical and surgical history, age, BMI, history of pelvic floor disorders, initial voiding pattern, physical examination, voiding diary, initial uroflowmetry and a urodynamic study. Postoperative follow-up and analysis of complications were also carried out.

RESULTS

A total of 52 patients were included in this study, 13 males and 39 females. Out of these patients, 17 patients (32.7%) with a median age of 47.3 years±18.1 benefited from definitive implantation of the sacral neuromodulation. The univariate analysis showed that age was the only significant variable in this study and the optimal age threshold was<58.5 years.

CONCLUSION

SNM is a therapy with significant clinical benefits and low morbidity for patients with chronic non-obstructive urinary retention. The results obtained need to be confirmed with a prospective study with a larger number of patients.

LEVEL OF EVIDENCE: 4

Two-year safety and efficacy outcomes for the treatment of overactive bladder using a long-lived rechargeable sacral neuromodulation system

AIMS

Sacral neuromodulation (SNM) therapy for overactive bladder (OAB) has proven long-term safety and efficacy. Historically, the only commercially available SNM device was nonrechargeable requiring replacement surgery due to battery depletion. The Axonics System is the first rechargeable SNM device and is qualified to last a minimum of 15 years in the body. The study objective was to evaluate the safety and efficacy of this rechargeable SNM system. This study reports 2-year outcomes.

METHODS

A total of 51 subjects were implanted with the Axonics System in a single nonstaged procedure. Subjects had OAB, confirmed on a 3-day voiding diary (≥8 voids/day and/or ≥2 incontinence episodes over 72 hours). Test Responders were defined as subjects that were responders at 1 month postimplant. The efficacy analysis included therapy responder rates, change in the quality of life, and subject satisfaction reported in Test Responders (n = 30) and all implanted subjects (n = 37) that completed the follow-up visits. Adverse events (AEs) are reported in all implanted subjects.

RESULTS

At 2 years, 90% of the Test Responders continued to respond to the therapy based on voiding diary criteria. Satisfaction with therapy was reported by 93% of subjects and 86% found their charging experience acceptable. Of the urinary incontinence Test Responders, 88% continued to be responders at 2 years, and 28% were completely dry. There were no unanticipated (AEs) or serious device-related AEs.

CONCLUSIONS

The Axonics System® provides sustained clinically meaningful improvements in OAB subjects at 2 years. There were no serious device-related AEs. Subjects reported continued satisfaction with their therapy.

Combination of sacral nerve and tibial nerve stimulation for treatment of bladder overactivity in pigs

PURPOSE

Sacral nerve and tibial nerve stimulation have been singly used to treat overactive bladder (OAB). This study evaluated the effects of both combined stimulation on treating bladder overactivity in pigs and explored a novel treatment modality for OAB.

METHODS

An implant-driven stimulator of the S3 spinal nerve was implanted in 5 pigs. The contralateral tibial nerve was stimulated by an external stimulator. Multiple cystometrograms were performed to determine the effects of single nerve stimulation and combination sacral nerve stimulation (SNS) and tibial nerve stimulation (TNS) on the micturition reflex by infusing normal saline (NS) or acetic acid (AA).

RESULTS

AA-induced bladder overactivity significantly reduced bladder capacity (BC) to 16.3 ± 2.2% of the NS control level (389.4 ± 27.68 ml; P < 0.01). When given a single stimulation, both SNS and TNS significantly increased the BC to 39.2 ± 1.6% and 34.9 ± 5.0% of the NS control level (P < 0.01), respectively. Combined SNS and TNS significantly increased the BC to 50.2 ± 5.2% of the NS control level (P < 0.01) and induced a superior inhibitory effect than SNS or TNS alone (P < 0.05).

CONCLUSIONS

Combination SNS and TNS induced a superior inhibitory effect on bladder overactivity in pigs compared to single stimulation and thus could be a novel treatment modality for OAB.

Involvement of opioid receptors in inhibition of bladder overactivity induced by sacral neuromodulation in pigs: A possible action mechanism

AIMS

To determine the role of opioid receptors in the inhibition of bladder overactivity by sacral neuromodulation (SNM) in pigs, and explore the possible mechanism of SNM.

METHODS

Both implant-driven stimulators of the S3 spinal nerve were implanted in seven pigs. Naloxone and tramadol were administered. Multiple cystometrograms were performed to determine the effects of SNM and opioid receptors on the micturition reflex by infusing normal saline (NS) or acetic acid (AA).

RESULTS

AA-induced bladder overactivity significantly reduced the bladder capacity (BC) to 29.9 ± 3.9% of the NS control level (413.1 ± 55.4 mL) (P < 0.01). SNM significantly increased the BC to 39.4 ± 5.5% of the NS control level (P < 0.03). In the absence of SNM, the cumulative dose of naloxone (0.02 and 0.2 mg/kg intravenously) did not significantly change the BC (25.1 ± 3.1% and 20.2 ± 3.1% of the NS control level, respectively) (P > 0.05). In the presence of SNM, both doses of naloxone significantly reduced the BC to 27.2 ± 3.0% and 25.1 ± 2.9% of the NS control level (P < 0.05), respectively. In the absence of SNM, tramadol did not significantly change the BC (31.5 ± 3.9% of the NS control level) (P > 0.05). In the presence of SNM, tramadol significantly increased the BC to 49.1 ± 6.1% of the NS control level (P < 0.01).

CONCLUSIONS

Opioid receptors play a role in inhibition of bladder overactivity during SNM. Combining SNM with tramadol could be a novel treatment modality for overactive bladder.

Initial experience with sacral neuromodulation for the treatment of lower urinary tract dysfunction in Brazil

Objectives:

We report on the short-term outcomes of sacral neuromodulation (SNM) for treatment of idiopathic lower urinary tract dysfunction in Brazil (procedures performed before 2014).

Materials and Methods:

Clinical data and surgical outcomes of patients who underwent SNM staged procedures were retrospective evaluated. Urological assessment included a focused medical history and physical examination, measurement of postvoid residual volumes, urodynamics, and bladder diaries. A successful test phase has been defined by improvement of at least 50% of the symptoms, based on bladder diaries.

Results:

From January 2011 to December 2013, eighteen consecutive patients underwent test phase for SNM due to refractory overactive bladder (15 patients), non-obstructive chronic urinary retention (2 patients), and bladder pain syndrome/interstitial cystitis (1 patient). All patients underwent staged procedures at four outpatient surgical centers. Mean age was 48.3±21.2 (range 10-84 years). There were 16 women and 2 men. Median follow-up was 3 months. Fifteen patients (83.3%) had a successful test phase and underwent implantation of the pulse generator (IPG). Median duration of the test phase was 7 days (range 5–24 days). Mean age was 45.6±18.19 years in responders versus 61.66±34.44 years in non-responders (p=0.242). Mean operative time (test phase) was 99±33.12 min in responders versus 95±35 min for non-responders (p=0.852). No severe complications were reported.

Conclusion:

SNM is a minimally invasive treatment option for patients with refractory idiopathic lower urinary tract dysfunction. Our initial experience with staged technique showed that tined-lead electrodes yielded a high rate of responders and favorable clinical results in the short-term follow-up.

[Tibial nerve transcutaneous stimulation for refractory idiopathic overactive bladder in children and adolescents]

INTRODUCTION

The purpose of this study was to evaluate safety and tolerability of transcutaneous tibial nerve stimulation (TENS) in patients under 15years of age with refractory overactive bladder.

MATERIALS AND METHODS

A retrospective analysis was conducted on outcomes of TENS (1daily 20-minute session, 10Hz) in patients with refractory overactive bladder, excluding patients with neurogenic bladder. Treatment efficacy was evaluated on symptomatic improvement and voiding schedule. Healing was defined as following: no recurrence of urinary tract infection, normal urodynamic voiding parameters, no nighttime continence disorder, normal uroflowmetry.

RESULTS

Nineteen consecutive patients with refractory overactive bladder were treated from November 2010 to March 2012 (11girls, 8boys, age 12.1±2.7 years). Three patients reported only daytime voiding disorders, the others reported daytime and nighttime voiding disorders. Ten patients reported febrile urinary tract infection (1 boy, 9 girls). The average length of treatment was 6 months. Two patients were lost to follow-up. Thirteen patients had only tibial TENS; 3 patients had tibial TENS and trospium chloride or desmopressin. At 1-month assessment, 16 patients out of 17 (94%) reported symptomatic improvement. At the end of treatment, 12 patients out of 17 (70%) met healing criteria (5 boys, 7girls), without relapse within 9 months. Three boys (18%) had partial improvement (no daytime wetting, but increased daytime frequency). No patient reported side effects.

CONCLUSION

Tibial TENS is a safe, non invasive and effective treatment in refractory overactive bladder in children. The success rate is 70%, with no side effect and no relapse at the end of the treatment in our study.

Contribution of sacral neuromodulation to manage persistent voiding dysfunction after surgery for deep infiltrating endometriosis with colorectal involvement: preliminary results

OBJECTIVE

Around 5% of women experience persistent voiding dysfunction after surgery for deep infiltrating endometriosis (DIE) with colorectal involvement. The gold standard to manage persistent voiding dysfunction is intermittent self-catherization, but this treatment may reduce quality of life of the patients due to care constraints. The objective of our study was to assess the contribution of sacral neuromodulation (SNM) in the management of persistent voiding dysfunction secondary to surgery for DIE with colorectal resection.

STUDY DESIGN

Five patients referred for persistent voiding dysfunction after surgery for DIE with colorectal resection were included and fitted with a temporary SNM system to test for feasibility. This consisted of placing an electrode unilaterally next to the S3 sacral nerve root and connecting it to an external pacemaker. The patients wore the electrode and the external neurostimulator for 21 days and kept a voiding diary. The SNM test was considered positive when a 50% decrease in self-catheterization was achieved after removal of the electrode. The system was implanted permanently in patients with a positive SNM test. Urodynamic tests were performed before and after the SNM test.

RESULTS

Two of the five patients had a positive SNM test and were implanted permanently. At 40 months the first patient had completely stopped self-catheterization and the second patient was performing self-catheterization twice a day with a post voiding residue volume of less than 100ml at 52 months.

CONCLUSION

SNM could be a curative technique in some patients with persistent voiding dysfunction after surgery for DIE. Further studies are required to better select patients who might benefit from SNM testing and subsequent device implantation.

[Urinary incontinence in men and women. Diagnostics and conservative therapy]

Urinary incontinence can affect men and women to the same degree. A differentiation is made between stress incontinence (i.e. urine discharge as a result of physical activities, sneezing or coughing), urge incontinence (i.e. strong urge to void with involuntary discharge of urine), mixed urinary incontinence and special forms. While men and women share the pathophysiology of urge-associated urinary incontinence, the multifactorial female urinary stress incontinence is in contrast to the stress incontinence in men which is almost exclusively caused by prostatectomy (postprostatectomy). The basic diagnostic procedure for urinary incontinence is largely non-invasive. Special diagnostic procedures are reserved for recurrences and preparation for operative measures. Therapy is oriented to the degree of suffering and patient compliance and incorporates conservative measures as first line therapy (e.g. lifestyle changes, bladder and continence training). Duloxetin is approved for the medicinal therapy of female urinary stress incontinence. The treatment of urge-associated urinary incontinence is primarily with anticholinergic agents. Alternatively, procedures for neuromodulation, a beta mimetic or injection therapy with botulinum toxin can be used in the future.

Convergence and cross talk in urogenital neural circuitries

Despite common comorbidity of sexual and urinary dysfunctions, the interrelationships between the neural control of these functions are poorly understood. The medullary reticular formation (MRF) contributes to both mating/arousal functions and micturition, making it a good site to test circuitry interactions. Urethane-anesthetized adult Wistar rats were used to examine the impact of electrically stimulating different nerve targets [dorsal nerve of the penis (DNP) or clitoris (DNC); L6/S1 trunk] on responses of individual extracellularly recorded MRF neurons. The effect of bladder filling on MRF neurons was also examined, as was stimulation of DNP on bladder reflexes via cystometry. In total, 236 MRF neurons responded to neurostimulation: 102 to DNP stimulation (12 males), 64 to DNC stimulation (12 females), and 70 to L6/S1 trunk stimulation (12 males). Amplitude thresholds were significantly different at DNP (15.0 ± 0.6 μA), DNC (10.5 ± 0.7 μA), and L6/S1 trunk (54.2 ± 4.6 μA), whereas similar frequency responses were found (max responses near 30–40 Hz). In five males, filling/voiding cycles were lengthened with DNP stimulation (11.0 ± 0.9 μA), with a maximal effective frequency plateau beginning at 30 Hz. Bladder effects lasted ∼2 min after DNP stimulus offset. Many MRF neurons receiving DNP/DNC input responded to bladder filling (35.0% and 68.3%, respectively), either just before (43%) or simultaneously with (57%) the voiding reflex. Taken together, MRF-evoked responses with neurostimulation of multiple nerve targets along with different responses to bladder infusion have implications for the role of MRF in multiple aspects of urogenital functions.

Sacral neuromodulation in patients with idiopathic overactive bladder after initial botulinum toxin therapy

PURPOSE

We evaluated whether patients with overactive bladder and incontinence who discontinued intravesical botulinum toxin therapy can be successfully treated with sacral neuromodulation.

MATERIALS AND METHODS

All patients who were referred to our center after discontinuation of botulinum toxin-A between 2005 and 2010 were included in this observational study. All patients underwent test stimulation with sacral neuromodulation and were evaluated with voiding diaries. Success was defined as more than 50% improvement in leakage episodes. Successful test stimulation was subsequently followed by a definitive implant. Patient satisfaction with sacral neuromodulation therapy was evaluated 1 year after the definitive implant.

RESULTS

A total of 20 patients were included in the study. Of these patients 17 (85%) had discontinued botulinum toxin-A because of lack of efficacy and 3 had been treated successfully with botulinum toxin-A but requested a more permanent solution. The mean interval between the botulinum toxin-A and the sacral neuromodulation test stimulation was 23 months. In 14 patients (70%) the test stimulation was successful and they received a definitive implant. Of the 14 patients 5 even showed a decrease of greater than 90% in leakage episodes. One year after implantation 11 patients (79%) were satisfied with the sacral neuromodulation treatment.

CONCLUSIONS

Despite the small sample size, this study indicates that patients who are dissatisfied with or in whom botulinum toxin-A treatment fails can respond successfully to sacral neuromodulation. The success rate of the test stimulation was comparable to that of patients who have never been treated with botulinum toxin-A. The 1-year satisfaction rate was comparable that of patients without a history of botulinum toxin-A treatment.

Efficacy of sacral neuromodulation on urological diseases: a multicentric research project

INTRODUCTION AND AIM OF THE STUDY

Sacral neuromodulation has been used as a safe, effective treatment option for patients with lower urinary tract dysfunction (LUTD). Several clinical studies demonstrated its positive effects on refractory urge incontinence, non-osbstructive urinary retention, urgency frequency syndrome, as well as on other non- urological disorders, such as fecal incontinence and chronic constipation. The aim of this research project was to evaluate the efficacy and safety of sacral neuromodulation on the management of LUTD refractory to the standardized first line treatment options.

MATERIALS AND METHODS

We retrospectively collected and evaluated data from patients undergoing sacral neuromodulations between September 2001 and November 2010 in 4 Urological Centres of North-East Italy. The patients were affected by Overactive Bladder Syndrome (OAB), Urinary Retention (UR), Fecal Incontinence (FI), Constipation (CO), Chronic Pelvic Pain (CPP). All the patients were evaluated with voiding diaries, before and after implantation.Patients included in the present evaluation were followed up in a network of 4 Italian urological centres, which participate to in the Italian Clinical Service project - a national urological database and medical care project aiming at describing and improving the use of implantable urological devices in the Italian clinical practice. Continuous normally distributed variables were reported as the mean value ± standard deviation (SD). Continuous non-normally distributed variables were presented as the median values and an interquartile range (IQR). The t-test and Wilcoxon test were used to compare continuous variables, as appropriate. A two-sided p <0.05 was considered statistically significant.

RESULTS

Overall, 157 patients underwent implantation of sacral neuromodulator during the period under review. Eighty-three out of 157 (53%) patients complained of OAB; 52 (33%) of UR; 5 (3%) of faecal incontinence; 4 (2%) of chronic constipation; 12 (8%) of CPP. The median follow- up was 11 months (IQR 1 - 91 months). In patients treated for OAB, we documented a statistically significant reduction in the mean number of: incontinence episodes/die, pads/die, daily micturitions, nocturnal micturitions and global micturitions. In patients treated for UR, we observed a statistically significant reduction in the mean post- voiding residual volume and in the number of self catheterization. Interpretation of results: It is difficult to translate into quantifiable data the subjective perception of improvement of the symptoms expressed by the patients, as they are frequently subjective perceptions, not always numeric data. This subjective perception makes it difficult to the clinician to evaluate the real outcomes of this procedure, and makes it difficult to achieve a complete follow-up.

CONCLUSIONS

This multicenter research project confirmed the midterm safety and effectiveness of sacral neuromodulation in the treatment of refractory overactive bladder syndrome and urinary retention, showing high cure rates and low complication rates.

Sacral neuromodulation for treating neurogenic bladder dysfunction: clinical and urodynamic study

PURPOSE

The efficacy of sacral neuromodulation for treating refractory idiopathic lower urinary tract dysfunction is now well established. Nevertheless, results of this technique in neurological patients are still controversial. The aim of this retrospective study was to assess the results of sacral neuromodulation in neurogenic bladder dysfunction.

MATERIALS AND METHODS

Between 1998 and 2008, a percutaneous nerve evaluation or a two-stage technique was performed in 62 patients (mean age 50.5 ± 14.8 years) with neurogenic lower urinary tract dysfunction. Before and during the temporary stimulation, each patient had a urodynamic evaluation and performed a bladder diary. The test was considered positive if the clinical and urodynamic improvement was over 50% and if the symptoms reappeared after turning the stimulation off.

RESULTS

Lower urinary tract dysfunction was detrusor overactivity in 34 cases and chronic urinary retention in 28 cases. A detrusor-sphincter dyssynergia (DSD) was associated in nine cases. Out of the 62 patients, 41 patients (66.1%) had more than 50% improvement on urodynamic evaluation and bladder diary and 37 were implanted. With a mean follow-up of 4.3 ± 3.7 years, results remained similar to the evaluation phase in 28 cases (75.7%), were partially altered in three cases (8.1%) and lost in six cases (16.2%). In these six cases, neuromodulation failed on average 12.0 ± 12.4 months after implantation.

CONCLUSION

Sacral neuromodulation seems to constitute a serious therapeutic option for patients with neurogenic lower urinary tract dysfunction. However, its results depend on the type of the underlying neurologic disease and in particular, whether it may progress or not.

Urinary incontinence in women: part 1 of a series of articles on incontinence

BACKGROUND

Urinary incontinence can arise in a woman of any age. Its prevalence is between 10% and 40%. The main clinical problems in urogynecology are stress urinary incontinence (involuntary leakage of urine on exertion, sneezing, or coughing) and the overactive bladder syndrome (nycturia, pollakisuria, and urinary urgency with or without incontinence).

METHOD

Selective literature search, with special attention to large-scale studies and to the guidelines of the German Society of Obstetrics and Gynecology (Deutsche Gesellschaft für Gynäkologie und Geburtshilfe, DGGG) and its Task Force on Urogynecology and Pelvic Floor Reconstruction (Arbeitsgemeinschaft Urogynäkologie und Beckenbodenrekonstruktion).

RESULTS

There are many diagnostic and therapeutic options, whose use should be based on the degree of the patient's suffering and on her motivation to be treated. Anticholinergic drugs are of established value in the treatment of overactive bladder. They are used in combination with possible lifestyle changes and bladder training. In some circum-stances, botulinum toxin injections can be considered as well. Stress incontinence should be treated conservatively (with pelvic floor training) before any surgical treatment is provided. The new tension-free vaginal tapes are just as effective as classic treatments, such as colposuspension, while being less invasive and enabling a more rapid recovery.

CONCLUSION

All women with urinary incontinence should undergo appropriate, specialized diagnostic evaluation and well-founded counseling in order to benefit from individualized treatment.

Bursting stimulation of proximal urethral afferents improves bladder pressures and voiding

Reflex bladder excitation has been evoked via pudendal nerve, pudendal nerve branch and intraurethral stimulation; however, afferent-evoked bladder emptying has been less efficient than direct activation of the bladder via sacral root stimulation. A stimulation method that improves activation of the urethra-bladder excitatory reflex with minimal sphincter recruitment may lead to improved bladder emptying. Fine wire electrodes were placed in the wall of the urethra in five cats. Placement of electrodes near the proximal urethra evoked bladder contractions with minimal sphincter activation. On these electrodes, lower frequency burst-patterned stimuli evoked greater bladder voiding efficiencies (71.2 +/- 27.8%) than other stimulus patterns on the same electrodes (50.4 +/- 41.5%, p > 0.05) or any stimulus pattern on electrodes that elicited urethral closure (16.5 +/- 12.7%, p < 0.05). Fine wire electrodes specifically targeted afferent fibers in the urethra, indicating the feasibility of clinical evaluations using the same method. This work may improve the translation of next generation neuroprostheses for bladder control.