Detailed Investigation of Bladder Diary Parameters During Sacral Neuromodulation in Patients With Overactive Symptoms.

AIMS: Sacral neuromodulation (SNM) is a well-accepted, minimally invasive modality for patients with overactive bladder (OAB). Successful response to SNM is defined as at least 50% improvement in key symptoms, evaluated in a bladder diary (BD). BDs provide much useful information on bladder behavior during daily life. The aim of this study is to investigate BD parameter changes during SNM therapy in patients with OAB. MATERIALS AND METHODS: The International Consultation on Incontinence Questionnaires (ICIQ)-BD was filled out by 34 patients with OAB, for three days at baseline and after three weeks of subthreshold sensory stimulation. The patients were considered responders for SNM when 50% improvement was seen in the BD. They underwent implantation of an internal pulse generator (IPG), and subsequently, an ICIQ-BD and a visual analog scale (VAS) evaluating bladder satisfaction during three days were filled out six weeks, six months, and one year after IPG implantation. RESULTS: IPGs were implanted in 29 patients (85%). The BD showed a significant decrease in 24-hour leakage at three weeks from 4.2 to 0.6 (-86%, p < 0.001), similar significant decreases at six weeks and six months, and at one year (-80%). Voided volume (VV) at corresponding bladder sensation codes was not different between baseline and at three weeks of tined-lead procedure (TLP) (p > 0.05), and at six weeks (p > 0.05), six months (p > 0.1), and one year of IPG (p > 0.08). After three weeks of TLP, urgency episodes decreased from 4.8 to 3.4 (-30%, p = 0.025), with 59% reduction at six-weeks IPG (p < 0.001) and 49% at six-months IPG (p = 0.013). At one year, a decrease from 4.7 to 2.3 (52% reduction, p = 0.017) was noted. VAS showed the strongest correlation with urgency (p < 0.001) and frequency (p = 0.006). No significant correlation was found with VV (p = 0.87). CONCLUSIONS: Our study describes how bladder sensation parameters change over time in patients on SNM. VV does not significantly increase, nor does frequency significantly decrease over the first year. Leaks and the percentage of urgency episodes significantly decrease, reaching a plateau level between six-weeks and six-months SNM.

[Postpartum fecal incontinence. State of the problem]. / Poslerodovoe anal'noe nederzhanie. Sostoyanie problemy.

A review of the current national and foreign literature is devoted to epidemiology, risk factors, causes, diagnosis and modern treatment approaches for fecal incontinence (FI). Incidence of FI in early and delayed period after childbirth is 30% or more. At the same time, up to 87% of postpartum injuries of anal sphincter remain undiagnosed. Importantly, routine caesarean section does not reduce the risk of incontinence. In addition to typical complaints of spontaneous gas and stool, diagnosis of FI after childbirth includes transrectal ultrasound, MRI, anorectal manometry and pudendal nerve terminal motor latency testing. Survey of proctologists from different regions of Russia revealed a high demand from medical community for educational programs devoted to diagnosis, treatment and rehabilitation of patients with postpartum perineal injuries.

Comparison of surgical techniques for optimal lead placement in sacral neuromodulation: a cadaver study.

BACKGROUND: Sacral neuromodulation (SNM) is a common treatment for patients with urinary and faecal incontinence. A close contact of the tined lead electrode with the targeted nerve is likely to improve functional outcome. The aim of this study was to compare the position of the SNM lead in relation to the sacral nerve by comparing different implantation techniques. METHODS: This cadaver study was conducted at the Division of Anatomy of Vienna's Medical University in October 2020. We dissected 10 cadavers after bilateral SNM lead implantation (n = 20), using two different standardized implantation techniques. The cadavers were categorized as group A (n = 10), representing the conventional guided implantation group and group B (n = 10), where SNM implantation was conducted with the novel fluoroscopy-guided "H"-technique. The primary goal was to assess the distance between the sacral nerve and the lead placement. RESULTS: The electrodes were inserted at a median angle of 58.5° (46-65°) in group A and 60° (50-65°) in group B, without reaching statistical significance. In 8 cadavers, the lead entered the S3 foramen successfully. The median distance of the lead to the nerve did not show a significant difference between both groups (E0: Group A: 0.0 mm vs. Group B: 0.0 mm, p = 0.969; E1: Group A: 0.0 mm vs. Group B: 0.5 mm p = 0.754; E2: Group A: 2.5 mm vs. Group B: 2.5 mm p = 1.000; E3: Group A: 3.5 mm vs. Group B: 4.0 mm p = 0.675). In 2 cases (20%) of the conventional group A, the lead was misplaced and located at the gluteal muscle. Perforation of the presacral fascia was observed in one lead placement in group A and in two placements in group B. CONCLUSIONS: Both standardized implantation techniques may ensure close electrode proximity to the targeted nerve. Misplacement of the electrode was more often observed with the conventional implantation technique.

Sacral neuromodulation for the treatment of overactive bladder: systematic review and future prospects.

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.

The Influence of Electrode Configuration Changes on the Sensory and Motor Response During (Re)Programming in Sacral Neuromodulation.

OBJECTIVES: This study aimed to assess the neurophysiological basis behind troubleshooting in sacral neuromodulation (SNM). Close follow-up of SNM patients with program parameter optimization has proven to be paramount by restoring clinical efficacy and avoiding surgical revision. MATERIALS AND METHODS: A total of 34 successful SNM patients (28 overactive bladder wet, six nonobstructive urinary retention) with an implantable pulse generator were included. All possible bipolar and monopolar electrode settings were tested at sensory threshold (ST) to evaluate sensory (mapped on a perineal grid with 1 cm2 coordinates) and motor (peak-to-peak amplitude and latency of muscle action potential) responses of the pelvic floor. Pelvic floor muscle electromyography was recorded using a multiple array probe, placed intravaginally. Parametric tests were used for paired data: repeated-measures ANOVA or t-test. A nonparametric test was used for paired data: Friedman ANOVA or Wilcoxon signed rank (WSR) test; p < 0.05 was considered statistically significant. If significant, ANOVA was followed by Dunn-Bonferroni post hoc analysis. RESULTS: Monopolar configurations showed significantly lower STs-1.38 ± 0.73 V vs 1.76 ± 0.89 V (paired t-test: p < 0.0001)-and presented with significantly higher peak-to-peak amplitudes-115.67 ± 79.03 µV vs 90.77 ± 80.55 µV (WSR: p = 0.005)-than bipolar configurations. When polarity was swapped, configurations with the cathode distal to the anode showed significantly lower STs, 1.73 ± 0.91 V vs 1.85 ± 0.87 V (paired t-test: p = 0.003), and mean peak-to-peak amplitudes, 81.32 ± 72.82 µV vs 100.21 ± 90.22 µV (WSR: p = 0.0001). Cathodal changes resulted in more changes in sensory responses than anodal changes (χ2 test: p = 0.044). In cathodal changes only, peak-to-peak amplitudes were significantly higher when the distance between electrodes was maximally spread (WSR: p = 0.046). CONCLUSIONS: From a neurophysiological point of view, monopolar configurations stimulated more motor nerve fibers at lower STs, therefore providing more therapeutic efficiency. Swapping polarity or changing the position of the cathode led to different sensory and motor responses, serving as potential reprogramming options.

Sacral Neuromodulation Changes Pelvic Floor Activity in Overactive Bladder Patients-Possible New Insights in Mechanism of Action: A Pilot Study.

OBJECTIVES: To evaluate if electrodiagnostic tools can advance the understanding in the effect of sacral neuromodulation (SNM) on pelvic floor activity, more specifically if SNM induces changes in pelvic floor muscle (PFM) contraction. MATERIALS AND METHODS: Single tertiary center, prospective study (October 2017-May 2018) including patients with overactive bladder syndrome undergoing SNM. Electromyography of the PFM was recorded using the Multiple Array Probe Leiden. The procedure consisted of consecutive stimulations of the lead electrodes with increasing intensity (1-3, 5, 7, 10 V). Recordings were made after electrode placement (T0) and three weeks of SNM (T1). Patients with >50% improvement were defined as responders, others as nonresponders. For the analyses, the highest electrical PFM response (EPFMR), defined as the peak-to-peak amplitude of the muscle response, was identified for each intensity. The sensitivity (intensity where the first EPFMR was registered and the normalized EPFMR as percentage of maximum EPFMR) and the evolution (EMFPR changes over time) were analyzed using linear mixed models. RESULTS: Fourteen patients were analyzed (nine responders, five nonresponders). For nonresponders, the PFM was significantly less sensitive to stimulation after three weeks (T0: 1.7 V, T1: 2.6 V). The normalized EPFMR was (significantly) lower after three weeks for the ipsilateral side of the PFM for the clinically relevant voltages (1 V: 36%-23%; p = 0.024, 2 V: 56%-29%; p = 0.00001; 3 V: 63%-37%; p = 0.0002). For the nonresponders, the mean EPFMR was significantly lower at 8/12 locations at T1 (T0: 109 µV, T1: 58 µV; mean p = 0.013, range <0.0001-0.0867). For responders, the sensitivity and evolution did not change significantly. CONCLUSIONS: This is the first study to describe in detail the neurophysiological characteristics of the PFM, and the changes over time upon sacral spinal root stimulation, in responders and nonresponders to SNM. More research is needed to investigate the full potential of EPFMR as a response indicator.

Sacral neuromodulation: troubleshooting needle placement.

INTRODUCTION AND HYPOTHESIS: The objective was to develop an instructional video that utilizes fluoroscopic images and anatomical landmarks to increase the surgeon's ability to troubleshoot optimal placement of the foramen needle and lead during a stage I sacral neuromodulation (SNM) procedure. METHODS: Eight different examples of suboptimal foramen needle placement with subsequent corrections during a SNM procedure were performed and recorded on a fresh female cadaver. RESULTS: Fluoroscopic images were obtained during the procedure, and illustrations of the posterior aspect of the sacrum highlighting the S3 foramina and nerve are shown for anatomical comparison. CONCLUSIONS: This video demonstrates how to efficiently identify and correct suboptimal foramen needle placement in order to obtain optimal lead placement during an SNM procedure. Understanding the relationship between the bony landmarks on fluoroscopy and the S3 nerve and foramen are important in order to understand how to correct a suboptimal foramen needle and thus achieve optimal lead placement.

Sacral neuromodulation: sacral anatomy and optimal lead placement.

INTRODUCTION AND HYPOSTHESIS: To develop an instructional video that correlates cadaveric anatomy with fluoroscopic images to assist in conceptualization of optimal placement of the foramen needle and lead to complete an efficient and successful sacral neuromodulation (SNM) procedure. METHODS: A SNM procedure was performed and recorded on a fresh female cadaver. Fluoroscopic images were obtained during the procedure to highlight the bony relationships to the S3 foramen and nerve. Dissection of the anterior and posterior sacrum was completed to highlight the tract of the S3 nerve. Techniques to increase the likelihood of optimal foramen needle and thus lead placement were highlighted. CONCLUSIONS: This video demonstrates how achieving optimal foramen needle placement within the S3 foramen is key to optimal lead placement. Understanding the relationship of the bony landmarks on fluoroscopy to the S3 nerve and foramen, seen in the cadaveric dissections, are important in understanding how to achieve optimal lead placement. This optimization should lead to decreased operating room time, maximization of programming options, and decreased amplitude requirements.

Unilateral versus bilateral sacral neuromodulation test in the treatment of refractory idiopathic overactive bladder: A randomized controlled pilot trial.

AIM: To compare treatment success rate in terms of improvement of bladder overactivity between unilateral and bilateral sacral neuromodulation testing. METHODS: A multicentric, parallel, randomized, open pilot trial (October 2012-September 2017) was conducted. Participants presented primary overactive bladder resistant to first-line treatments. Patients were excluded in case of secondary bladder, pelvic, or neurological condition. Patients were randomized between bilateral testing (n = 28) or unilateral testing (n = 27), to determine the best functional response before final implantation. The primary outcome was the rate of patients presenting at least 50% of clinical improvement at 1 month on urinary frequency, number of urge incontinence episodes or number of urinary urgency episodes. Symptom severity, implantation success rate, uroflowmetry, device tolerance, complications, and quality of life were also assessed. RESULTS: Fifty-five patients have been included. The rate of patients presenting at least one significant clinical improvement at month 1 was 62% in the bilateral group versus 84% in the unilateral group (P = .0891), RR = 0.74 (0.51; 1.07). There was no significant difference between bilateral and unilateral groups in terms of improvement of urinary frequency (0% and 17%; P = .1115), number of urge incontinence episodes (52% and 63%; P = .4929) or number of urinary urgency episodes (57% and 74%; P = .2411). More complications were reported in the bilateral group than in the unilateral group (9 [47%] vs 4 [16%], respectively; P = .0239). CONCLUSION: Systematic bilateral sacral neuromodulation testing before final implantation did not appear to increase success rate compared with unilateral stimulation in the treatment of overactive bladder.

Pelvic Floor Muscle Electromyography as a Guiding Tool During Lead Placement and (Re)Programming in Sacral Neuromodulation Patients: Validity, Reliability, and Feasibility of the Technique.

PURPOSE: To assess the validity, reliability, and feasibility of electromyography (EMG) as a tool to measure pelvic floor muscle (PFM) contractions during placement and (re)programming of the tined lead electrodes in sacral neuromodulation (SNM) patients. MATERIALS AND METHODS: Single tertiary center, prospective study conducted between 2017 and 2019 consisting of three protocols including a total of 75 patients with overactive bladder (wet/dry) or nonobstructive urinary retention. PFM EMG was recorded using the multiple array probe (MAPLe), placed intravaginally. All stimulations (monophasic pulsed square wave, 210 µsec, 14 Hz) were performed using Medtronic's standard SNM stimulation equipment. During lead implantation, all four lead electrodes were stimulated with fixed increasing stimulation intensities (1-2-3-5-7-10 V). During lead electrode (re)programming, five bipolar lead electrode configurations were stimulated twice up to when an electrical PFM motor response (EPFMR), sensory response, and pain response were noted (i.e., the threshold), respectively. Additionally, amplitude and latency of the EPFMRs were determined. Validity, reliability, and feasibility were statistically analyzed using the intraclass correlation coefficient, weighted Cohen's kappa and linear regression, respectively. RESULTS: Validity: EPFMRs were strongly associated with visually detected PFM motor responses (κ = 0.90). Reliability: EPFMR amplitude (ICC = 0.99) and latency (ICC = 0.93) showed excellent repeatability. Feasibility: linear regression (EPFMR threshold = 0.18 mA + 0.76 * sensory response threshold) showed an increase in the sensory response threshold is associated with a smaller increase in EPFMR threshold, with the EPFMR occurring before or on the sensory response threshold in 83.8% of all stimulations. CONCLUSIONS: Measuring PFM contractions with EMG during placement and (re)programming of lead electrodes in SNM patients is valid, reliable, and feasible. Therefore, the use of PFM EMG motor responses could be considered as a tool to assist in these procedures.

Neural pathway of bellows response during SNM treatment revisited: Conclusive evidence for direct efferent motor response.

BACKGROUND: In sacral neuromodulation (SNM) patients, it is thought the bellows response elicited upon sacral spinal nerve stimulation is reflex-mediated. Therefore the mechanism of action of SNM is considered to be at the spinal or supraspinal level. These ideas need to be challenged. OBJECTIVE: To identify the neural pathway of the bellows response upon sacral spinal nerve stimulation. DESIGN, SETTING, AND PARTICIPANTS: Single tertiary center, prospective study (December 2017-June 2019) including 29 patients with overactive bladder refractory to first-line treatment. INTERVENTION: Recording of the pelvic floor muscle response (PFMR) using a camcorder and electromyography (EMG) (intravaginal probe and concentric needles) upon increasing stimulation during lead or implantable pulse generator placement. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The lowest stimulation intensity needed to elicit a visual PFMR and electrical PFMR was determined. Electrical PFMRs were subdivided according to their latency. OUTCOME: the association between visual and electrical PFMRs. Statistical analyses were performed using the weighted kappa coefficient. RESULTS: Three different electrical PFMRs could be identified by surface and needle EMG, corresponding with a direct efferent motor response (R1), oligosynaptic (R2), and polysynaptic (R3) afferent reflex response. Only the R1 electrical PFMR was perfectly associated with the visual PFMR (κ = 0.900). CONCLUSIONS: The visual PFMRs upon sacral spinal nerve stimulation are direct efferent motor responses. A reopening of the discussion on the mechanism of action of SNM is possibly justified.

Pelvic floor activation upon stimulation of the sacral spinal nerves in sacral neuromodulation patients.

PURPOSE: To assess the activation of the different parts of the pelvic floor muscles (PFM) upon electrical stimulation of the sacral spinal nerves while comparing the different lead electrode configurations. MATERIAL AND METHODS: PFM electromyography (EMG) was recorded using an intravaginal multiple array probe with 12 electrodes pairs, which allows to make a distinction between the different sides and depths of the pelvic floor. In addition concentric needle EMG of the external anal sphincter was performed to exclude far-field recording. A medtronic InterStim tined lead (model 3889) was used as stimulation source. Standard SNM parameters (monophasic pulsed square wave, 210 microseconds, 14 Hz) were used to stimulate five different bipolar electrode configurations (3+0-/3+2-/3+1-/0+3-/1+3-) up to and around the sensory threshold. Of each EMG signal the stimulation intensity needed to evoke the EMG signals as well as its amplitude and latency were determined. Linear mixed models was used to analyse the data. RESULTS: Twenty female patients and 100 lead electrode configurations were stimulated around the sensory response threshold resulting in 722 stimulations and 12 times as many (8664) EMG recordings. A significant increase in EMG amplitude was seen upon increasing stimulation intensity (P < .0001). Large differences were noted between the EMG amplitude recorded at the different sides (ipsilateral>posterior>anterior>contralateral) and depths (deep>center>superficial) of the pelvic floor. These differences were noted for all lead electrodes configurations stimulated (P < .0001). Larger EMG amplitudes were measured when the active electrode was located near the entry point of the sacral spinal nerves through the sacral foramen (electrode #3). No differences in EMG latency could be withheld, most likely due to the sacral neuroanatomy (P > .05). CONCLUSIONS: A distinct activation pattern of the PFM could be identified for all stimulated lead electrode configurations. Electrical stimulation with the most proximal electrode (electrode #3) as the active one elicited the largest PFM contractions.

Concomitant Sacral Neuromodulation and Gynecologic Surgery: A Single-Institution Experience.

AIMS: Sacral Neuromodulation (SNM) is a safe and minimally invasive treatment for urinary and fecal pelvic floor disorders (PFDs). With a high prevalence of women reporting multiple PFDs, knowledge regarding concomitant surgery may inform optimal patient care. Our literature search did not identify any published data on this topic, thus we sought to report our experience with concomitant SNM and gynecologic surgery. Our primary objective was to identify the rate of adverse events among cases. Secondarily, we reviewed the anesthetics used to identify potential associations when performing combined surgery. MATERIALS AND METHODS: This was retrospective case series of women undergoing SNM at a single academic center from 2012 to 2018. Cases were identified using current procedural terminology codes for SNM and common gynecologic procedures. These electronic medical records were reviewed to identify cases that occurred concomitantly in addition to obtaining demographics, adverse events, type of anesthesia, and overnight hospital stay. Descriptive data analysis was performed with Excel. RESULTS: Of 200 identified cases of SNM, 15 (7.5%) were concomitantly performed with another procedure. Most concomitant surgeries occurred with insertion of implantable pulse generator. Three minor adverse events occurred: two urinary tract infections and one occurrence of urinary retention. Eight (53%) cases were performed under general anesthesia while seven (46%) received monitored sedation. CONCLUSIONS: No serious adverse events or anesthesia-related complications were identified in this series. While general anesthesia was used more often, it was in accordance with our standard practice for the gynecologic procedures. This study supports the safety of concomitant gynecologic and SNM surgery.

Timing of sacral neurostimulation is important for increasing bladder capacity in the anesthetized rat.

We assessed the effects of limited application of sacral neurostimulation (SNS) during bladder filling on bladder capacity using our previously published SNS model in rats. Female Sprague-Dawley rats (n = 24) were urethane anesthetized (1.2 g/kg sc) and implanted with jugular venous and transvesical bladder catheters. L6/S1 nerve trunks were isolated bilaterally, and two electrodes were placed on each exposed nerve. True bladder capacity (TBC) was determined using stable single-fill cystometrograms. In the first series of experiments, SNS was applied at the onset of bladder filling for 25%, 50%, 75%, and 100% of the previous control filling cycle duration (n = 10). In the second series of experiments, SNS was applied during the first, second, third, and fourth 25% and the first and second 50% of the control fill. In the first series, a significant increase in TBC was observed only when SNS was applied for 75% or 100% of the control fill duration (30% and 35%, respectively, P < 0.05). In the second series, significant increases in TBC only occurred during the fourth 25% period and second 50% period (32% and 43%, respectively, P < 0.001). Results from the second series also revealed an increase in subsequent single-fill bladder capacities (TBC) only when SNS was applied during the second 50% of the prior fill cycle. These data indicate that the application of SNS during the final 50% of the bladder fill cycle is necessary and sufficient for increasing bladder capacity.

[The use of surgical neuromodulation to treat chronic pelvic pain]. / Primenenie khirurgicheskoi neiromoduliatsii dlia lecheniia khronicheskoi tazovoi boli.

Chronic pelvic pain (CPP) is a pain syndrome that is very difficult to treat. The effectiveness of CPP treatment remains low despite the use of integrated approaches. That is why it is necessary to search for new treatment approaches and methods. Surgical neuromodulation has recently been used increasingly often to treat CPP. OBJECTIVE: To evaluate the effectiveness of different types of neurostimulation in patients with chronic pelvic pain. MATERIAL AND METHODS: Thirty-two patients were treated at the N.N. Burdenko National Scientific and Practical Center for Neurosurgery. All the patients were diagnosed with CPP and transferred to the Center because of unsatisfactory results of earlier treatment. The mean duration of pain was 8.6 years (range: 1-31 years). Pain intensity and the neuropathic component of the pain syndrome were assessed using the conventional scales and questionnaires (VAS, LANSS, Pain Detect, and DN4). The levels of anxiety, depression, and catastrophic pain were also assessed. The effect of pain on quality of life was evaluated using the modified Brief Pain Inventory (BPI). All the selected patients underwent trial lead implantation at the first stage. Sacral root stimulation was used in 15 patients (unilateral one in 8 patients and bilateral one in 7 patients); three patients underwent spinal cord stimulation; 14 patients were treated with combined neurostimulation. RESULTS: In 27 (84.37%) patients, the trial period was regarded as positive and the systems were implanted for chronic neurostimulation. After one year of stimulation, the mean VAS score for pain intensity was 3.53 (compared to 8.61 before the surgery). Regarding quality of life, the most significant effects of treatment were as follows: the number of pain paroxysms was reduced; physical self-maintenance, social life, sleep, and sexual activity were improved; and daily physical activity was increased. CONCLUSION: . Neurostimulation ensures a stable pain relief and improves quality of life in patients with chronic pelvic pain refractory to conservative treatment.

Needle Placement and Position of Electrical Stimulation Inside Sacral Foramen Determines Pelvic Floor Electromyographic Response-Implications for Sacral Neuromodulation.

BACKGROUND: Lead placement within the sacral foramen in sacral neuromodulation patients is guided by visual assessment of the contraction of the pelvic floor musculature (PFM) and/or verbal assessment of the sensation and location of sensation upon stimulation. Generally, lead placement is proceeded by needle probing. This study evaluates which location inside a single sacral foramen would be most ideal for the release of the permanent electrode lead, by measuring electromyographic (EMG) motor responses of the PFM upon stimulation of a peripheral nerve evaluation (PNE) needle. MATERIALS AND METHODS: In eight patients, four standard PNE needles, and in one patient, two PNE needles, were introduced into the same foramen, parallel to the midline and parallel to each other. Position was verified by X-ray. Needles were stimulated (square pulsed waves, 210 µsec, 14 Hz) at increasing amplitudes (1-2-3-5-7-10 mA). PFM EMG was measured using the Multiple Array Probe (MAPLe) placed intravaginally or intrarectally, with 24 derivations. For this study, the mean (normalized) EMG was taken of all electrodes and different positions within the foramen were compared using the Wilcoxon signed rank test. RESULTS: A total of 202 PFM EMG measurements were recorded upon stimulation. EMG motor responses of the PFM for current stimulation = <2 mA showed statistically significant higher mean (normalized) EMG values for needles positioned cranial, medial, and cranial-medial, in comparison to needles positioned caudal, lateral, and caudal-lateral (p = 0.004; p = 0.021; p = 0.002). CONCLUSIONS: Our data suggest stronger PFM contractions are elicit in cranial- and medial-placed PNE needles upon stimulation with clinically relevant current amplitudes (≤ 2 mA). Placement of the lead should aim for this spot in the foramen.

Repeatability of tools to assist in the follow up and troubleshooting of sacral neuromodulation patients using the sensory response.

PURPOSE: Sacral neuromodulation (SNM) is an established minimally invasive therapy for functional disorders of the pelvic organs in which electrodes are stimulated in proximity of the sacral spinal nerves. Reprogramming of the electrodes is regularly required and is based on the sensory response. This study assesses the repeatability of a pelvic chart and grading system to enable a more objective assessment of the sensory response upon electrode stimulation. MATERIAL AND METHODS: In 26 SNM patients, with OAB or NOUR, assessment of the sensory response was done using the sensory threshold (ST) and a pelvic chart with 1 cm2 coordinates, each coordinate corresponding with a dermatome and location of sensation (LoS). A grading system was developed based upon the ST and LoS. Repeatability of ST was assessed using a two-way mixed effects, absolute agreement, single rater/measurement intraclass correlation coefficient (ICC), and displayed using a correlation and Bland Altman plot. Repeatability of dermatomes, LoS, and grading system was assessed using kappa correlation coefficient. RESULTS: On average, 1.55 ± 0.85 coordinates were used to point out the area where the stimulation was perceived. The mean amount of coordinates between the area pointed at during the first and second measurement was 0.47 ± 0.74. ST showed excellent repeatability (ICC 0.93, 95%CI 0.90-0.94, P < 0.001). Dermatomes, LoS and grading system showed a substantial to almost perfect agreement (κ = 0.740-0.833, P < 0.001). CONCLUSIONS: The pelvic chart and grading system, using the sensory response upon electrode stimulation, are repeatable tools and can be used to assist in follow up and troubleshooting of SNM patients.

Comparative effectiveness of one versus two-stage sacral neurostimulation device placement.

OBJECTIVE: Sacral neurostimulation (SNS) is an effective third-line treatment for overactive bladder. We sought to compare the cost of standard two-stage SNS device placement to that of a combined one-stage placement using a Markov chain model. METHODS: Costs were defined using Medicare outpatient reimbursement rates. The model was developed as follows: With the two-stage approach, patients underwent initial lead placement with fluoroscopy and those who converted to stage two underwent permanent generator placement week later. Patients who did not convert underwent lead removal. Patients undergoing a one-stage procedure had initial lead and generator placement at the same time. Patients with success underwent no further procedure. Patients without success could opt for generator and lead removal. Cost effectiveness of one versus two-stage placement depended on successful conversion rate. RESULTS: Reimbursement included physician, anesthesia, facility and device fees. In a two-stage procedure, initial cost of lead placement was $6170. With successful conversion, cost of a second procedure with permanent lead and generator placement was $18,474. Patients who failed test phase underwent lead removal for a cost of $2879. In a one-stage procedure approach, initial cost of permanent lead and generator placement was $18,474. Patients with a successful outcome had no additional costs. Patients with an unsuccessful outcome could have the lead and generator removal for a cost of $5758. If the conversion rate from testing phase to permanent placement was greater than 71%, a one-stage approach proved to be cost effective. CONCLUSIONS: Identifying patients with favorable risk factors for success may predict those patients who warrant a one-stage approach.

Sacral neuromodulation using the standardized tined lead implantation technique with a curved vs a straight stylet: 2-year clinical outcomes and sensory responses to lead stimulation.

OBJECTIVES: To assess clinical follow-up data over 24 months, comparing the use of a curved vs straight stylet in patients undergoing sacral neuromodulation using the standardized tined lead implantation technique. PATIENTS AND METHODS: We conducted a single tertiary-centre, prospective study between August 2013 and June 2015 involving 40 patients with overactive bladder and 15 with non-obstructive urinary retention refractory to first-line treatment. The primary outcome was successful tined lead procedure according to intention-to-treat analyses at 12 and 24 months. The secondary outcome was number of optimal electrode configurations during programming. Statistical analysis was performed using plain non-parametric tests for numerical and categorical data. RESULTS: Successful tined lead procedures were achieved in 33 of 35 patients (94%) implanted with the curved stylet compared with 13 of 20 patients (65%) implanted with the straight stylet (P = 0.005). Intention-to-treat analyses at 12 and 24 months showed success rates of 94% and 91%, respectively, in the curved stylet group vs 65% and 45%, respectively, in the straight stylet group (P = 0.002 and P < 0.001). In the curved stylet group, 60% and 25% of the electrode configurations were considered optimal and poor, respectively, vs 40% and 37%, respectively, in the straight stylet group (P < 0.001). CONCLUSIONS: The use of the standardized implantation technique with the curved stylet led to more successful tined lead procedures, better success rates after 2 years of follow-up and a greater number of optimal electrode configurations when compared to use of the straight stylet.

Chronic refractory constipation due to neurogenic bowel dysfunction can be successfully treated by sacral neurostimulation.

INTRODUCTION: In the last few decades, sacral neurostimulation (SNS) has proven to be an effective treatment option for functional bowel disorders. Experience concerning the role of SNS in the treatment of chronic constipation due to neurogenic bowel dysfunction (NBD) however is limited. METHODS: In this report, we present the case of a 44-year old patient, with chronic refractory neurogenic constipation after a spontaneous cerebral hemorrhage, who was treated with SNS. RESULTS: Prior to treatment with SNS, the Constipation Scoring System showed a score of 22/30. Three months after SNS implantation, this score was reduced to 5/30. Patient had successful evacuation of stool every one to two days. Medication could be reduced to 15 drops of picosulphate per day. Patient experienced a significant improvement in quality of life. CONCLUSIONS: We believe that SNS could offer a safe, effective and relatively cost-effective treatment for patients with NBD refractory to conservative treatment.