Sacral Neuromodulation (SNM): Can Percutaneous Nerve Evaluation (PNE) Really Compete with Stage 1 to Predict Outcomes?

To estimate the long-term cost-effectiveness of specialised treatment options for medically refractory idiopathic overactive bladder (OAB) wet. The cost-effectiveness of competing treatment options for patients with medically refractory idiopathic OAB wet was estimated from the perspective of the National Health Service in the UK. We compared sacral nerve stimulation (SNS) with percutaneous nerve evaluation (PNE) or tined-lead evaluation (TLE) with optimal medical therapy (OMT), botulinum toxin type A (BoNT-A) injections, and percutaneous tibial nerve stimulation (PTNS). We used a Markov model with a 10-year time horizon for all treatment options with the exception of PTNS, which has a time horizon of 5years. Costs and effects (measured as quality-adjusted life years) were calculated to derive incremental cost-effectiveness ratios (ICERs). Direct medical resources included are: device and drug acquisition costs, pre-procedure and procedure costs, and the cost of managing adverse events. Deterministic sensitivity analyses were performed to test robustness of results. At 5years, SNS (PNE or TLE) was more effective and less costly than PTNS. Compared with OMT at 10years, SNS (PNE or TLE) was more costly and more effective, and compared with BoNT-A, SNS PNE was less costly and more effective, and SNS TLE was more costly and more effective. Decreasing the BoNT-A dose from 150 to 100IU marginally increased the 10year ICERs for SNS TLE and PNE (SNS PNE was no longer dominant). However, both SNS options remained cost-effective. In the management of patients with idiopathic OAB wet, the results of this cost-utility analysis favours SNS (PNE or TLE) over PTNS or OMT, and the most efficient treatment strategy is SNS PNE over BoNT-A over a 10-year period.

Sacral Nerve Stimulation for Refractory Overactive Bladder in the Elderly Population

Patients with voiding dysfunction, such as overactive bladder (OAB) syndrome and non-obstructive retention, who have failed conservative treatment are candidates for sacral nerve stimulation (SNS). Sacral nerve stimulation was originally described by Tanagho and Schmidt.1 Medtronic received United States Food and Drug Administration (FDA) approval for Interstim in July 1998 for urge incontinence. To proceed with full implant, patients were initially tested with a percutaneous nerve evaluation (PNE). The percutaneous permanent tined lead (PPTL) was released in 2002 and is now the most commonly used procedure performed prior to a patient receiving a permanent implant.2 The advantage of the PPTL over PNE is higher implantation rates 88% versus 46%.3 Richard and colleagues used an interesting approach looking at the PNE as an adjunct to the PPTL and the implanted pulse generator implant. They performed a retrospective chart review of 106 patients who underwent 116 PNEs. Of these 116 patients, 62 (53%) had a successful PNE. Of these successful cases, 57 (92%) went on to an implant. Using the PNE allowed them to pre-select patients for PPTL, which increased their overall success.4 The authors address noteworthy considerations in their approach to SNS. The most worthwhile is the use of a 60% goal for symptom improvement compared to the standard 50%, which was an initial arbitrary goal. Some may argue we should consider an even higher improvement rate, possibly 70%. The authors astutely point out that the placebo success rate for anticholinergics can be as high as 60%, clearly explaining why some patients do not improve even after a full implant. Considering the significant expense of the product, elimination of the placebo effect would decrease cost, improve efficacy and prevent unnecessary procedures. Additionally, the authors discuss the prospect that using this three-stage approach may reduce the overall cost of SNS, as the cost of the PPTL staged approach is significantly less than a PNE. This may reduce the general cost to society; however, with the lower success rate of PNE, one cannot help but wonder if treatment is being withheld from some patients who are suffering. The authors should be commended for reviewing their data and trying to identify cost-efficient and more efficacious methods of providing care for their patients. A large multi-centre trial evaluating cost and efficacy would be optimal, but unfortunately improbable. As new treatment modalities enter the market, we must continue to assume the responsibility to weigh their costs and benefits to achieve the best outcomes for the greatest number of patients.

Sacral neuromodulation (SNM) is an effective treatment for patients with voiding dysfunctions, such as overactive bladder (OAB) and nonobstructive urinary retention (NOUR), that are resistant or intolerant to conservative treatments. These conditions significantly impact quality of life and healthcare costs. This thesis reviews studies on SNM and OAB, focusing on patient selection, lead placement, testing techniques, and safety and efficacy to enhance successful SNM therapy outcomes. SNM has proven to be safe and effective for treating OAB in the short-, medium-, and long-term without limiting other treatment options. No major irreversible complications were noted. Key factors for successful SNM therapy include patient selection, lead placement, and testing techniques. While no consensus on predictive factors for patient selection exists, the first-stage tined lead procedure has shown more reliable testing results and better patient selection for SNM compared to percutaneous nerve evaluation (PNE). The test stimulation phase remains the most crucial prognostic factor for long-term success. Chapter 2 investigates if a “supervised” three-week test phase increases the success rate and relates the need for reprogramming during the test phase to the one-year outcome for implanted patients. Our data showed that weekly follow-ups and reprogramming during a three-week test phase increased the number of patients who responded successfully and proceeded to implantation and chronic SNM treatment with proven durable success. Thus, a supervised three-week test phase is recommended. Chapter 3 assesses the neurophysiological basis behind troubleshooting and reprogramming by analyzing motor and sensory responses to lead stimulation. Monopolar configurations provided more efficient therapy delivery than bipolar configurations. Swapping polarity or changing the cathode position led to different sensory and motor responses, offering potential reprogramming options. These findings serve as a guiding tool during reprogramming and a basis for further research on clinical outcomes. Chapters 4 and 5 explore the use of pelvic floor muscle (PFM) electromyography (EMG) during lead placement and programming as a predictor of a successful SNM test phase. Intraoperative PFM EMG under general anesthesia aids accurate lead targeting. A correlation between therapy efficacy and PFM motor response during programming was found, linking lead placement to SNM outcomes. Responders generally exhibited lower motor thresholds (MT), lower MT/sensory thresholds ratios, higher compound muscle action potentials (CMAPs), and higher continuous PFM activation at subsensory stimulation levels. Chapter 6 examines Burst stimulation, a new SNM paradigm, showing it induced higher bladder and urethral pressure increases than conventional SNM, suggesting a higher degree of autonomic nervous system stimulation. Individual parameters such as frequency and amplitude may be important for SNM efficacy, warranting further research. Chapter 7 discusses the main findings in the context of current knowledge. Chapter 8 provides prospects for SNM in a rapidly evolving patient population.

There is limited evidence to support the efficacy of sacral neuromodulation (SNM) for older adults with overactive bladder (OAB). This study aims to report outcomes following SNM among nursing home (NH) residents, a vulnerable population with high rates of frailty and comorbidity. This is a retrospective cohort study of long-stay NH residents who underwent a trial of percutaneous nerve evaluation (PNE) or Stage 1 permanent lead placement (Stage 1) between 2014 and 2016. Residents were identified using the Minimum Data Set linked to Medicare claims. The primary outcome of this study was successful progression from trial to implant. Rates of 1-year device explant/revisions were also investigated. Trial of SNM was observed in 1089 residents (mean age: 77.9 years). PNE was performed in 66.9% of residents and 33.2% underwent Stage 1. Of Stage 1 procedures, 23.8% were performed with simultaneous device implant (single-stage). Overall, 53.1% of PNEs and 72.4% of Stage 1 progressed to device implant, which was associated with Stage 1 procedure versus PNE (adjusted relative risk [aRR]: 1.34; 95% confidence interval [95% CI]: 1.21-1.49) and female versus male sex (aRR: 1.26; 95% CI: 1.09-1.46). One-year explant/revision was observed in 9.3% of residents (6.3% for PNE, 10.5% for Stage 1, 20.3% single-stage). Single stage procedure versus PNE was significantly associated with device explant/revision (aRR: 3.4; 95% CI: 1.9-6.2). In this large cohort of NH residents, outcomes following SNM were similar to previous reports of younger healthier cohorts. Surgeons managing older patients with OAB should use caution when selecting patients for single stage SNM procedures.

Introduction Sacral Neuromodulation (SNM) is a minimally invasive treatment for OAB patients following failure of conventional interventions. Patient selection, lead placement, and testing technique are important pillars in optimizing success rates. Areas covered A comprehensive literature search was conducted on ‘sacral neuromodulation’ and ‘overactive bladder.’ There was no date restriction, with the last search dated 31 May 2021. Patient selection, lead placement, test phases, safety, efficacy, and available devices are thoroughly discussedLastly, future perspectives will be presented with the anticipated trajectory of sacral neuromodulation over the next five years. Expert opinion/commentary SNM has proved to be a safe and effective therapy on the short-, medium- and long-term without precluding any other treatment options. In all studies reviewed, no life threatening or major irreversible complications were presented. However, surgical re-intervention rates were high with a median of 33.2% (range: 8–34%) in studies with at least 24 months follow-up. No true consensus could be made regarding prognostic factors. However, optimized lead placement, consequent ideal motor thresholds, and the use of a curved stylet theoretically facilitates reaching maximal success with SNM. Test phase success rates increased to such a level that from a cost-effective point of view, single-stage implants could be considered. Abbreviations: OAB: overactive bladder; SNM: sacral neuromodulation; BoNT-A: Botulinum toxin A; PFM EMG: pelvic floor muscle electromyography; IPG: implantable pulse generator; PNE: percutaneous nerve evaluation; FSTLP: first-stage tined lead procedure; NLUTD: neurogenic lower urinary tract dysfunction; ITT: intention to threat; PPMC: per protocol modified completers; PPC: per protocol completers; AE: adverse event; MRI: magnetic resonance imaging; RCT: randomized controlled trial

Satisfaction and Patient Experience With Sacral Neuromodulation: Results of a Single Center Sample Survey

Sacral nerve stimulation (SNS) is effective for some patients with faecal incontinence. Before insertion of a costly implant, percutaneous nerve evaluation (PNE) is undertaken to identify patients likely to report success from SNS. The aim of this study was to determine whether variables of anal sphincter function measured by anal acoustic reflectometry (AAR) could predict the outcome of PNE for faecal incontinence. Women with faecal incontinence undergoing PNE were recruited. AAR, followed by anal manometry, was performed on the day of surgery, immediately before PNE. The outcome of PNE was determined by bowel diary results and incontinence severity score. Patients with a successful PNE outcome were compared with those with an unsuccessful outcome; logistic regression analysis was used to identify any independent predictors of success. Fifty-two patients were recruited, of whom 32 (62 per cent) had a successful PNE outcome and 20 (38 per cent) an unsuccessful outcome. The AAR variable opening pressure was significantly greater in patients who subsequently had a successful PNE result compared with the pressure in patients who did not (28 versus 17 cmH2 O; P = 0·008). No difference was seen in the manometric equivalent, maximum resting pressure. Opening pressure was an independent predictor of success with an odds ratio of 1·08 (95 per cent confidence interval 1·01 to 1·16; P = 0·018). AAR is a sensitive test of sphincter function and can identify differences between patients who respond to PNE and those who do not. Opening pressure is an independent predictor of success in PNE, and may be of value in the selection of patients for this expensive treatment option.

Sacral neuromodulation using a 2-staged approach is an established therapy for fecal incontinence. Office-based percutaneous nerve evaluation is a less-invasive alternative to the stage 1 procedure but is seldom used in the evaluation of patients with fecal incontinence. The aim of this study was to determine the clinical success of percutaneous nerve evaluation versus a staged approach. This was a retrospective review of a prospectively maintained, single-institution database of patients treated with sacral neuromodulation for fecal incontinence. This study was conducted at a single academic medical center. Eighty-six consecutive patients were treated with sacral neuromodulation for fecal incontinence. Percutaneous nerve evaluation was compared with a staged approach. The primary outcome measured was the proportion of patients progressing to complete implantation based on >50% improvement in Wexner score during the testing phase. Percutaneous nerve evaluation was performed in 45 patients, whereas 41 underwent a staged approach. The mean baseline Wexner score did not differ between testing groups. Success was similar between the staged approach and percutaneous nerve evaluation (90.2% versus 82.2%; p = 0.36). The mean 3-month Wexner score was not significantly different between testing methods (4.4 versus 4.1; p = 0.74). However, infection was more likely to occur after the staged approach (10.5% versus 0.0%; p < 0.05). This study was limited by its retrospective nature and potential for selection bias. Percutaneous nerve evaluation offers a viable alternative to a staged approach in the evaluation of patients for sacral neuromodulation in the setting of fecal incontinence. Not only are success rates similar, but percutaneous nerve evaluation also has the benefit of limiting patients to 1 operating room visit and has lower rates of infection as compared with the traditional staged approach for sacral neuromodulation.

Sacral Neuromodulation in Women With Idiopathic Detrusor Overactivity Incontinence: Decreased Overactivity but Unchanged Bladder Contraction Strength and Urethral Resistance During Voiding

BACKGROUND: Sacral nerve stimulation (SNS) approved for use in North America since 1997 despite the fact that the concept of using SNS to treat patients with voiding dysfunction discussed first almost 50 years ago. AIM: The objectives of the study were to assess the effectiveness of SNS the short and long term for patients with overactive bladder (OAB) dysfunction and its relation to age, gender, and causes. PATIENTS AND METHODS: This is a clinical prospective study that involved 50 cases (32 females and 18 males) with OAB. It was carried out at Ibn Sina Hospital, and the neurosciences hospital in Baghdad/Iraq from April 2015 to April 2018. All the patients were assessed preoperatively and certain inclusion criteria were used. The patients went through the 2 stage implantations of the Medtronic InterStim®. The patients were assessed at 6 months (short term) and 2 years (long term) postoperatively. RESULTS: The results of our patients were analyzed with respect to age, gender, causes of OAB, and post-operative complications. We found that younger age patients, female patients, and patients with neurogenic causes of OAB showed a better response in both the short- and long-term follow-up. CONCLUSION: Considerable progress has been made in the surgical management of OAB. Proper selection of patients is the key to the success of SNS, and female patients have better results compared to male patients. Furthermore, younger patients and patients with neurogenic causes did better than older patients and patients with idiopathic causes. SNS is a safe minimally invasive surgery with a low complication rate, and the 2 stages procedure has better results than the percutaneous nerve evaluation.

Sacral nerve stimulation (SNS) is an established treatment option for faecal incontinence. Cyclic stimulation will improve the longevity of the implanted stimulator, but little is known about its efficacy. The aim of this retrospective clinical study was to assess the efficacy of cyclic SNS for faecal incontinence. Sixty-three patients underwent percutaneous nerve evaluation (PNE) test with a 2-week period of continuous SNS. The PNE test was deemed positive in 42 patients (67 %) who underwent implantation with permanent stimulator. All 42 patients were initially stimulated in a cyclic manner with stimulation for 20 s followed by 8 s without. During follow-up, the stimulator was explanted in 2 patients and permanently turned off in one due to the loss of effect. A postal questionnaire including the Wexner score, a general quality of life (Qol) score, and a bowel habit diary was distributed to 39 patients. The questionnaire was returned by 29/39 (74 %) of the patients. Median duration of follow-up was 16 (range 3-34) months. The Wexner score and the general QoL score were significantly improved compared to pre-treatment values. Some 18 patients (62 %) were still treated with cyclic stimulation at follow-up, reporting more frequent episodes of urgency without incontinence (p = 0.020) compared to symptoms during the PNE test. Patients who had changed to continuous stimulation due to a suboptimal effect during follow-up reported more frequent episodes of urgency with incontinence (p = 0.034), minor soiling (p = 0.045) and days wearing pads (p = 0.027) compared with symptoms during the PNE test. Cyclic stimulation seems effective for most patients treated with SNS for faecal incontinence.

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. 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). AA-induced bladder overactivity significantly reduced bladder capacity (BC) to 16.3±2.2% of the NS control level (389.4±27.68ml; 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). 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.

AimThe aim of this study is to evaluate the acute effects of sacral neuromodulation (SNM) on various urodynamic parameters.MethodsPatients with overactive bladder and detrusor overactivity (DO) who were planned for percutaneous nerve evaluation (PNE) were included. Directly after the PNE, a urodynamic study (UDS) was performed. The stimulation was turned off during the first UDS (UDS 1), and during the second filling cycle, stimulation was turned on (UDS 2). The UDS was followed by a test phase of 1 week and the bladder diaries were evaluated during an outpatient clinic visit. Primary outcome measures were the differences in UDS parameter values with SNM off and on.ResultsTen female patients were included in the study and completed the study protocol. Eight patients showed ≥50% improvement of symptoms following a test phase. There were no differences between UDS 1 and UDS 2 in the UDS parameters; bladder volume at first sensation, bladder volume at first DO, highest DO pressure, bladder capacity, maximum flow rate, and pressure at maximum flow rate.DiscussionNone of the aforementioned urodynamic parameters was influenced by acute SNM in patients who responded to SNM. To the best of our knowledge, this is the first study investigating the acute effects of SNM on bladder function.

We have reviewed the evidence published on botulinum toxin A (BoNT/A), percutaneous tibial nerve stimulation (PTNS), and sacral nerve stimulation (SNS) in the management of overactive bladder (OAB). BoNT/A is effective irrespectively of the number of previous anticholinergic treatments and of the reason for failure. Doses up to 360U 3-monthly are well tolerated. BoNT/A is well tolerated and effective also in the pediatric population. Bladder instillation of liposome encapsulated BoNT/A is a new approach, deserving further research. When using PTNS, motor response from the electrical stimulus is not required, a sensory response suffices. PTNS has a lasting effect compared to oxybutynin alone. SNS is superior to standard medical treatment but the combination of SNS and anticholinergics is more effective than anticholinergic alone. The evidence published in the last 18 months has increased the level of evidence on safety and effectiveness of BoNT/A, PTNS, and SNS in the management of OAB. BoNT/A is now recommended as standard third-line treatment for OAB (in the USA) and urgency incontinence (in the USA and in Europe) in selected patients refractory to pharmacological therapy. All available third-line treatment options for OAB/urgency urinary incontinence should be offered before surgery is contemplated. http://links.lww.com/COU/A7.