Percutaneous tibial nerve stimulation: the Urgent PC®device

Efficacy and safety of tibial nerve stimulation using a wearable device for overactive bladder

OBJECTIVE

To evaluate the efficacy and safety of a wearable, smartphone-controlled, rechargeable transcutaneous tibial nerve stimulation (TTNS) device in patients with overactive bladder (OAB).

PATIENTS AND METHODS

This multicentre, prospective, single-blind, randomised clinical trial included eligible patients with OAB symptoms who were randomly assigned to the stimulation group or sham group. The primary efficacy outcome was change from baseline in voiding frequency/24 h after 4 weeks of treatment. The secondary efficacy outcomes included changes in bladder diary outcomes (urgency score/void, nocturia episodes/day, micturition volume/void, and incontinence episodes/day), questionnaires on Overactive Bladder Symptom Score (OABSS), Patient Perception of Bladder Condition (PPBC), and American Urological Association Symptom Index Quality of Life Score (AUA-SI-QoL) at baseline and after 4 weeks of treatment. Device-related adverse events (AEs) were also evaluated.

RESULTS

In the full analysis set (FAS), the mean (sd) change of voiding frequency/24 h in the stimulation group and sham group at 4 weeks were -3.5 (2.9) and -0.6 (2.4), respectively (P < 0.01). Similar results were obtained in the per-protocol set (PPS): -3.5 (2.9) vs -0.4 (2.3) (P < 0.01). In the FAS and PPS, micturition volume/void significantly improved at 4 weeks (P = 0.01 and P = 0.02). PPBC improvement almost reached significance in the FAS (P = 0.05), while it was significant in the PPS (P = 0.02). In the FAS and PPS, AUA-SI-QoL significantly improved at 4 weeks in the two groups (P < 0.01 and P < 0.01), whereas there were no significant differences in urgency score/void, nocturia episodes/day or OABSS between the groups. Also, no device-related serious AEs were reported.

CONCLUSIONS

The non-invasive neuromodulation technique using the novel ambulatory TTNS device is effective and safe for treating OAB. Its convenience and easy maintenance make it a new potential home-based treatment modality. Future studies are warranted to confirm its longer-term efficacy.

Pilot Study of a Novel At-Home Posterior Tibial Nerve System for Overactive Bladder Syndrome

IMPORTANCE

Urgency urinary incontinence and overactive bladder are common conditions. Third-line therapies are often underutilized because of either being too invasive or being burdensome for the patient.

OBJECTIVE

We aimed to determine the efficacy and acceptability of a noninvasive, home-based posterior tibial nerve treatment system for the treatment of overactive bladder syndrome.

STUDY DESIGN

In this pilot study, 10 postmenopausal women with urgency urinary incontinence were given the SoleStim System for home-based posterior tibial nerve stimulation. Symptoms at baseline and completion of the 8-week study were determined by 3-day voiding diary and quality-of-life questionnaire (Overactive Bladder Questionnaire) to assess for reduction in incontinence episodes.

RESULTS

All patients were 100% adherent to the SoleStim System application over the 8-week period and reported statistically significant reductions in the mean number of voids (-16.3%, P = 0.022), urgency episodes (-31.2%, P = 0.02), and urgency urinary incontinence episodes (-31.4%, P = 0.045). Forty percent of participants reported a decrease of ≥50% in their urgency urinary incontinence episodes. SoleStim was scored a value of 1.8 ± 2.0 (mean ± SD) on a 10-point usability scale, indicating that it was highly acceptable from an ease-of-use perspective. No adverse events were reported.

CONCLUSIONS

The SoleStim System improved key overactive bladder (frequency, urgency, and urgency urinary incontinence episodes) and quality-of-life metrics. The results from this pilot study suggest that the SoleStim System may be a safe, effective, and highly acceptable at-home overactive bladder therapy.

The Investigation of Percutaneous Tibial Nerve Stimulation (PTNS) as a Minimally Invasive, Non-Surgical, Non-Hormonal Treatment for Overactive Bladder Symptoms

BACKGROUND

Overactive bladder (OAB) syndrome affects 10-15% of women, severely impacting their quality of life. First-line treatments include behavioural and physical therapy, and second-line medical treatments include medications such as vaginal oestrogen, anticholinergic medications, and ß3-adrenergic agonists-with potential adverse side effects including dizziness, constipation, and delirium, particularly affecting elderly populations. Third-line treatments include more invasive measures, including intradetrusor botulinum injections or sacral nerve modulation, with percutaneous tibial nerve stimulation (PTNS) being a potential alternative treatment.

AIMS

The aim of this study was to explore the long-term efficacy of PTNS treatment for OAB in an Australian cohort.

MATERIALS AND METHODS

This is a prospective cohort study. Patients underwent Phase 1 treatment, whereby women received PTNS treatment once per week for 12 weeks. Following Phase 1, women entered Phase 2, whereby they received 12 PTNS treatments over 6 months. Their response to treatment was measured by obtaining data before and after each phase using ICIQ-OAB and the Australian Pelvic Floor Questionnaire (APFQ).

RESULTS

Phase 1 included 166 women, with 51 completing Phase 2. There was a statistically significant reduction in urinary urgency (29.8%), nocturia (29.8%), incontinence (31.0%), and frequency (33.8%) compared to the baseline. Patients who completed Phase 2 also showed a statistically significant reduction in urinary frequency (56.5%).

CONCLUSIONS

Overall, the results from this study are positive and support that PTNS is a minimally invasive, non-surgical, non-hormonal, and effective treatment for OAB. These results suggest that PTNS may be a second-line treatment for patients with OAB not responding to conservative management or for patients aiming to avoid surgical approaches.

Peripheral neuromodulation in women with overactive bladder syndrome: a systematic review

INTRODUCTION

Overactive bladder syndrome (OBS) is a urological disorder characterized by urinary urgency, increased frequency, nocturia, and may be associated with urge urinary incontinence. Posterior tibial nerve peripheral neuromodulation (PTNS) is globally recognized within the treatment options available, although an optimal protocol has not been tested. The objective of this review is to collect the evidence available on the most widely used protocol of the PTNS technique in obtaining good results in the treatment for women with OBS.

EVIDENCE ACQUISITION

A systematic review of the scientific literature was carried out in PubMed, Embase, WoS and Scopus databases. A total of 222 results were obtained, with 58 duplicates, of which 8 studies met the established inclusion criteria, all of them randomized clinical trials.

EVIDENCE SYNTHESIS

The included works show that the most widely used PTNS technique with beneficial results in women with OBS is the percutaneous route with a needle placed 5-6cm proximal to the tibial malleolus, posterior to the edge of the tibia, with the following parameters: 1 weekly session of 30minutes duration for 12 weeks, the use of pulse widths of 200μs with frequency of 20Hz.

CONCLUSION

PTNS may have beneficial and safe short-term effects in women with OBS. Despite showing statistically significant improvements in clinical symptoms, further research is needed to obtain clear scientific evidence on the optimal protocol for treating women with OBS.

The long-lasting post-stimulation inhibitory effects of bladder activity induced by posterior tibial nerve stimulation in unanesthetized rats

Tibial nerve stimulation (TNS) is one of the neuromodulation methods used to treat an overactive bladder (OAB). However, the treatment mechanism is not accurately understood owing to significant differences in the results obtained from animal and clinical studies. Thus, this study was aimed to confirm the response of bladder activity to the different stimulation frequencies and to observe the duration of prolonged post-stimulation inhibitory effects following TNS. This study used unanesthetized rats to provide a closer approximation of the clinical setting and evaluated the changes in bladder activity in response to 30 min of TNS at different frequencies. Moreover, we observed the long-term changes of post-stimulation inhibitory effects. Our results showed that bladder response was immediately inhibited after 30 min of 10 Hz TNS, whereas it was excited at 50 Hz TNS. We also used the implantable stimulator to observe a change in duration of the prolonged post-stimulation inhibitory effects of the TNS and found large discrepancies in the time that the inhibitory effect lasted after stimulation between individual animals. This study provides important evidence that can be used to understand the neurophysiological mechanisms underlying the bladder inhibitory response induced by TNS as well as the long-lasting prolonged post-stimulation effect.

Tibial nerve stimulation in the treatment of overactive bladder syndrome: technical features of latest applications

PURPOSE OF REVIEW

Overactive bladder syndrome (OAB) is a chronic condition, which can be treated by tibial nerve stimulation. The present review will focus on the technical aspects, advantages, drawbacks, and limitations of the latest available applications of posterior tibial nerve stimulation.

RECENT FINDINGS

We describe the technical aspects of recent developed implants and techniques of tibial nerve stimulation in a transcutaneous, percutaneous, and minimal invasive way. All different treatment options have advantages and disadvantages based on type of surgery, energy transfer, impedance, treatment setting options, risk of migration, and patient usability, which are described in this review. Only devices with data that are publicly available were included.

SUMMARY

New technologies are on their way in the field of tibial nerve stimulation for the treatment of OAB. Technical aspects are important to demonstrate safety and efficacy and user friendliness in order to obtain high acceptance of the various devices.

Long-term real-life adherence of percutaneous tibial nerve stimulation in over 400 patients

Background

Percutaneous tibial nerve stimulation (PTNS) is used as a treatment to reduce the complaints of overactive bladder (OAB). Although it is rewarding therapy patients need maintenance treatment to preserve the beneficial effect.

Aim

This real‐life retrospective study was performed to assess the feasibility of PTNS adherence.

Materials & methods

All patients who underwent PTNS were retrospectively included. We analyzed the following: indication, kind of treatments (pharmacologic and third‐line therapy) before and after PTNS treatment, time and reason for quitting therapy. Statistical analysis was done by performing competitive‐risk analysis and Kaplan‐Meier curves. Patients were categorized into four groups. Group 1: all patients; group 2: all patients on maintenance PTNS therapy (continuing after 12 weeks); group 3: patients on maintenance PTNS therapy excluding the following: (a) patients with initial good response who seized treatment due to death, (b) patient who successfully switched to transcutaneous stimulation, (c) patients who were cured of their OAB symptoms, or (d) patients who relocated; and group 4: group 3 but excluding those who stopped treatment because of nonmedical reasons (physical strain, inconveniencies associated with visiting the hospital).

Results

Four‐hundred two patients (70% female) with a median age of 70 years underwent PTNS. Underlying treatment indications were: OAB‐wet (54%) and OAB‐dry (29%). The median follow‐up (FU) of group 1 was 4 months. Fifty‐seven percent (N = 228) of the patients received maintenance PTNS therapy. Median FU in group 4 was 46 months (range, 3‐111 months). Over 40% of the maintenance patients stopped PTNS because of logistic reasons and physical strain during an FU time of 6 years.

Conclusion

The real‐world data described here with is in line with earlier published work in terms of the success rate of OAB treatment. However, over 40% quit their therapy due to nonmedical reasons.

Lumbosacral spinal cord epidural stimulation improves voiding function after human spinal cord injury

Deficits in urologic function after spinal cord injury (SCI) manifest both as a failure to store and empty, greatly impacting daily life. While current management strategies are necessary for urological maintenance, they oftentimes are associated with life-long side effects. Our objective was to investigate the efficacy of spinal cord epidural stimulation (scES) as a promising therapy to improve bladder control after SCI. A bladder mapping study was undertaken for sixteen sessions over the course of four months in an individual with chronic, motor complete SCI. Varying combinations of stimulating cathode electrodes were initially tested during filling cystometry resulting in the identification of an effective configuration for reflexive bladder emptying at the caudal end of the electrode array. Subsequent systematic testing of different frequencies at a fixed stimulus intensity and pulse width yielded lowest post-void residual volumes at 30 Hz. These stimulation parameters were then tested in four additional research participants and found to also improve reflexive voiding efficiency. Taken together with SCI studies on step, stand, voluntary motor control and cardiovascular regulation, these findings further corroborate that scES has an all-encompassing potential to increase the central state of excitability, allowing for the control of multiple body functions, including the urological system.

A pilot study assessing the efficacy of posterior tibial nerve stimulation in the treatment of low anterior resection syndrome

BACKGROUND

Low anterior resection for rectal cancer often results in severe bowel dysfunction, specifically low anterior resection syndrome (LARS), with symptoms such as incontinence, urgency, and frequent bowel movements. Percutaneous tibial nerve stimulation (PTNS) resulted in a high rate of success in patients with fecal incontinence. The aim of this study was to evaluate the effectiveness of treatment with PTNS in LARS and to identify predictors of the outcome of the technique.

METHODS

The study was conducted from May 2012 to April 2015 at the Alvaro Cunqueiro Hospital, University Hospital Complex of Vigo, Spain. Ten patients with LARS were recruited consecutively. All patients underwent 2 sessions per week (30 min each one) for 6 weeks. Patients were followed for 3 weeks, and those who had a significant clinical improvement were recruited to a second phase of PTNS. Some patients presenting with relapse during follow-up underwent an additional phase of PTNS. Outcome measures included Wexner scores, quality of life scores, and urgency of defecation.

RESULTS

Three patients did not complete the treatment due to poor response in the first phase. Incontinence was reduced in the remaining seven of ten patients. The median Wexner score at initial patient evaluation was 14 (IQR 10.75-18.5), which decreased to 10 (IQR 6.5-18) after treatment (p = 0.034). A statistically significant improvement was demonstrated in quality of life scale, lifestyle, depression, and daily defecation urgency (p < 0.05). LARS Score improvement was observed in five patients (50%) with a total resolution of LARS in 2 (20%).

CONCLUSIONS

PTNS is an ambulatory treatment that could play an important role in the context of a multimodal treatment approach in patients with LARS. It could be a first-line treatment to identify non-responders to conservative management who need different and more invasive treatments.

Evaluation of the axonics modulation technologies sacral neuromodulation system for the treatment of urinary and fecal dysfunction

INTRODUCTION

Sacral neuromodulation (SNM) remains one of the few effective treatments for refractory bladder and bowel dysfunction. However, SNM is associated with frequent need for surgical intervention, in many cases because of a failed battery. A rechargeable SNM system, with a manufacturer-reported battery life of 15 years or more, has entered post-market clinical testing in Europe but has not yet been approved for clinical testing in the United States. Areas covered: We review existing neuromodulation technologies for the treatment of lower urinary tract and bowel dysfunction and explore the limitations of available technology. In addition, we discuss implantation technique and device specifications and programming of the rechargeable SNM system in detail. Lastly, we present existing evidence for the use of SNM in bladder and bowel dysfunction and evaluate the anticipated trajectory of neuromodulation technologies over the next five years. Expert commentary: A rechargeable system for SNM is a welcome technological advance. However surgical revision not related to battery changes is not uncommon. Therefore, while a rechargeable system would be expected to reduce costs, it will not eliminate the ongoing maintenance associated with neuromodulation. No matter the apparent benefits, all new technologies require extensive post-market monitoring to ensure safety and efficacy.

Tibial nerve stimulation to inhibit the micturition reflex by an implantable wireless driver microstimulator in cats

BACKGROUND

Traditional tibial nerve stimulation (TNS) has been used to treat overactive bladder syndrome (OAB), but there are some shortcomings. Thus, a novel alternative is needed for the treatment of OAB. The study investigated the effects of a new type of tibial nerve microstimulator on the micturition reflex in cats.

METHODS

An implantable wireless driver microstimulator was implanted around the tibial nerve in 9 α-chloralose anesthetized cats. Cystometry was performed by infusing 0.9% normal saline (NS) or 0.25% acetic acid (AA) through a urethral catheter. Multiple cystometrograms were performed before, during, and after TNS to determine the inhibitory effect of the microstimulator on the micturition reflex.

RESULTS

TNS at 2 threshold (T) intensity significantly increased the bladder capacity (BC) during NS infusion. Bladder overactivity was irritated by the intravesical infusion of 0.25% AA, which significantly reduced the BC compared with the NS infusion. TNS at 2 T intensity suppressed AA-induced bladder overactivity and significantly increased the BC compared with the AA control.

CONCLUSION

The implantable wireless driver tibial nerve microstimulator appears to be effective in inhibiting the micturition reflex during physiologic and pathologic conditions. The implantable wireless driver tibial nerve microstimulator could be used to treat OAB.

Inhibition and Excitation of Bladder Function by Tibial Nerve Stimulation Using a Wirelessly Powered Implant: An Acute Study in Anesthetized Cats

PURPOSE

Tibial nerve stimulation is a minimally invasive neuromodulation treatment of overactive bladder. However, in addition to our limited understanding of the underlying mechanisms, there are also questions regarding the long-term delivery of tibial nerve stimulation therapy in patients. We aimed to characterize the effects of stimulation frequency using a wirelessly powered implantable stimulation device.

METHODS AND MATERIALS

Six α-chloralose anesthetized adult male cats were used in this study. A multicontact lead was surgically implanted subcutaneously in the hind limb and used to stimulate the tibial nerve. Using an isovolumetric bladder a short duration of electrical pulses was applied at amplitudes 3 times the motor threshold and at frequencies from 2 to 20 Hz.

RESULTS

Implant driven stimulation of the tibial nerve resulted in frequency dependent activation of bladder reflexes. Low frequency tibial nerve stimulation (2 Hz) consistently evoked excitatory responses (mean ± SE 32.9% ± 3.8%). In contrast, higher frequency tibial nerve stimulation (6 to 20 Hz) inhibited bladder function (overall mean 14.9% ± 2.4%). Although low foot motor thresholds were achieved at initial implantation (mean 0.83 ± 0.05 mA), a notable elevation in threshold amplitude was observed 5 hours after implantation.

CONCLUSIONS

To our knowledge this study provides the first evidence of frequency dependent modulation of bladder function in anesthetized cats. The inhibitory influence of tibial nerve stimulation at frequencies above 6 Hz transitioned to an excitatory effect at 2 Hz. Taken together these preclinical data support the feasibility of using a wirelessly powered implantable device to potentially modulate bladder function in patients.

Posterior tibial nerve stimulation in adults with overactive bladder syndrome: A systematic review of the literature

Overactive bladder (OAB) is a common condition that can significantly impact on a patient’s quality of life. Treatments include conservative methods (patient education, lifestyle modifications, bladder retraining), pharmacotherapy (anticholinergics and adrenoreceptor agonists), intravesical botulinum toxin A injections and surgical strategies (including neuromodulation, augmentation cystoplasty and urinary diversion). There has been increased interest in neuromodulation over recent years and accumulating evidence for percutaneous tibial nerve stimulation (PTNS). We have reviewed the currently available clinical evidence in a systematic, reproducible fashion. PTNS has been shown in randomised controlled studies (against sham/placebo and against anticholinergics) to be safe and effective in treating OAB. Cost effectiveness analyses for PTNS have shown mixed results depending on the length of follow-up. PTNS is a useful adjunct to therapy in OAB for patients who have failed conservative and pharmacotherapy. Further research is required to define its place in the OAB treatment algorithm.

Sacral neuromodulation and peripheral nerve stimulation in patients with anal incontinence: an overview of techniques, complications and troubleshooting

Sacral neuromodulation (SNM) therapy has revolutionized the management of many forms of anal incontinence, with an expanded use and a medium-term efficacy of 75% overall. This review discusses the technique of SNM therapy, along with its complications and troubleshooting and a discussion of the early data pertaining to peripheral posterior tibial nerve stimulation in incontinent patients. Future work needs to define the predictive factors for neurostimulatory success, along with the likely mechanisms of action of their therapeutic action.

Combination of foot stimulation and tramadol treatment reverses irritation induced bladder overactivity in cats

PURPOSE

We determined whether transcutaneous electrical foot stimulation combined with a low dose of tramadol (Sigma-Aldrich®) could completely suppress bladder overactivity.

MATERIALS AND METHODS

Repeat cystometrograms were performed in 18 α-chloralose anesthetized cats by infusing the bladder with saline or 0.25% acetic acid. Transcutaneous electrical stimulation (5 Hz) of the cat hind foot at 2 to 4 times the threshold intensity needed to induce observable toe movement was applied to suppress acetic acid induced bladder overactivity. Tramadol (1 to 3 mg/kg intravenously) was administered to enhance foot inhibition.

RESULTS

Acetic acid irritated the bladder, induced bladder overactivity and significantly decreased bladder capacity to a mean ± SE of 26% ± 5% of saline control capacity (p <0.01). Without tramadol, foot stimulation at 2 and 4 threshold intensity applied during acetic acid cystometrograms significantly increased bladder capacity to a mean of 47% ± 5% and 62% ± 6% of saline control capacity, respectively (p <0.05). Without foot stimulation, tramadol (1 mg/kg) only slightly changed bladder capacity to a mean of 39% ± 2% of saline control capacity (p >0.05), while 3 mg/kg significantly increased capacity to 85% ± 14% that of control (p <0.05). However, 1 mg/kg tramadol combined with foot stimulation increased bladder capacity to a mean of 71% ± 18% (2 threshold intensity) and 84% ± 14% (4 threshold intensity), respectively, which did not significantly differ from saline control capacity. In addition, long lasting (greater than 1.5 to 2 hours) post-stimulation inhibition was induced by foot stimulation combined with 3 mg/kg tramadol treatment.

CONCLUSIONS

This study suggests a new treatment strategy for overactive bladder by combining foot stimulation with a low dose of tramadol, which is noninvasive and has potentially high efficacy and fewer adverse effects.

Comparison of neural targets for neuromodulation of bladder micturition reflex in the rat

Spinal nerve (SN) stimulation inhibits the bladder rhythmic contraction (BRC) in anesthetized rats. This preparation was used to study the effects of electrical stimulation of the tibial nerve (TN) and the dorsal nerve of the clitoris (DNC) on BRC. Stimulation of the TN and DNC for 10 min produced a frequency- and intensity-dependent attenuation of the frequency of bladder contractions. As observed with the SN, 10-Hz stimulation of either TN or DNC produced the greatest degree of inhibition, with lower or higher frequencies being either less efficacious or inactive. In contrast to the prolonged inhibition produced by SN stimulation, both TN and DNC stimulation produced “short” lasting inhibition of bladder contractions and the maximal inhibition occurred during stimulation. TN stimulation was effective over only a narrow range of current intensities [3–4 × motor threshold current for inducing a toe twitch ( Tmot)] and only at a frequency of 10 Hz. Stimulation of TN at 10 Hz, 3 × Tmot inhibited BRC to 23% of control. Ten-hertz DNC stimulation at 2 × TEAS, the threshold current for evoking a reflex anal sphincter contraction, decreased the frequency of contractions to 4% of control. Although compared with the respective threshold current the BRC response was more sensitive to DNC compared with TN stimulation, the absolute current required to reduce BRC using DNC stimulation appeared to be higher. Comparing the effects of TN and DNC stimulation to our previous results with SN stimulation, SN stimulation produces the largest duration and efficacy of bladder inhibition.

Efficacy and effectiveness of percutaneous tibial nerve stimulation in the treatment of pelvic organ disorders: a systematic review

OBJECTIVE

This systematic review aimed to determine the efficacy and effectiveness of percutaneous tibial nerve stimulation (PTNS) on symptoms of overactive bladder (OAB) and pelvic organ disorders, pain, adverse events (AEs), and quality of life (QoL).

METHODS

A literature search was performed in September 2011 in the databases MEDLINE, CINAHL, and EMBASE. Hand searching of references was conducted. Only randomized controlled trials (RCTs) and controlled clinical trials (CCTs) with adult patients were included.

RESULTS

Seven studies met the eligibility criteria. Five RCTs indicated improvement (range 36.7-80%) on OAB symptoms, frequency, urgency, nocturia, and incontinence. One CCT reported improvement (mean 15.7) in 53% of the subjects on fecal incontinence (FI) symptoms on an FI Questionnaire (range 0-20). One RCT showed more than 50% improvement on pain (40%) and symptom scores (66.6%) in chronic pelvic pain (CPP). Limitations are the small amount, overall low quality, and variety in outcome measures of included studies. Only minor AEs were reported. No meta-analysis was performed as a consequence of heterogeneous data.

CONCLUSIONS

This systematic review provides evidence for the efficacy of PTNS on symptoms, pain, and QoL measures of OAB, FI and category IIIB CP/CPP. Evidence of effectiveness was found on symptoms and QoL for OAB. The total amount of seven included studies, from which even the most favorable study has some potential bias, is too small to draw firm conclusions. Independent high quality RCTs are necessary to confirm and delineate the range of therapeutic effects of PTNS in this region. PTNS is a safe intervention.

Involvement of opioid receptors in inhibition of bladder overactivity induced by foot stimulation in cats

PURPOSE

We examined the role of opioid receptors in the inhibition of bladder overactivity induced by electrical stimulation of the foot.

MATERIALS AND METHODS

Experiments were done in 6 cats under α-chloralose anesthesia when the bladder was infused with saline or 0.25% acetic acid. Naloxone (1 mg/kg intravenously) was administered to block opioid receptors. To modulate reflex bladder activity electrical stimulation (5 Hz, 0.2 millisecond pulse width) was applied to the foot via skin surface electrodes at intensities of multiple times the threshold needed to induce observable toe movement.

RESULTS

Acetic acid irritated the bladder, induced bladder overactivity and significantly decreased bladder capacity to a mean ± SE 25.3% ± 5.9% that of saline control capacity (p = 0.0001). Foot stimulation at 4T suppressed acetic acid induced bladder overactivity and significantly increased bladder capacity to 47.1% ± 5.9% of control (p = 0.0007). Naloxone did not significantly change bladder capacity during acetic acid irritation but it completely eliminated the inhibition of bladder overactivity induced by foot stimulation.

CONCLUSIONS

Results indicate that opioid receptors have an important role in foot afferent inhibition of bladder overactivity. This raises the possibility that opioid receptors might be used as a pharmacological target to enhance the efficacy of foot stimulation for inhibiting bladder overactivity.

Post-stimulation inhibitory effect on reflex bladder activity induced by activation of somatic afferent nerves in the foot

PURPOSE

We determined whether transcutaneous electrical stimulation of somatic afferent nerves in the foot of cats would induce a post-stimulation increase in bladder capacity.

MATERIALS AND METHODS

In 12 α-chloralose anesthetized cats electrical stimulation (5 Hz) was applied to the skin of the hind foot for 2, 30-minute periods via dual pad electrodes attached on the plantar and dorsal surfaces (combination 1 and 2) or at 2 sites on the plantar surface (combination 1 and 3). The post-stimulation effect was examined by repeat cystometrogram after 30-minute stimulation. In the control group of 12 cats isovolumetric contractions were allowed to continue during each 30-minute period without stimulation.

RESULTS

Stimulation inhibited isovolumetric rhythmic bladder contractions. Bladder capacity was not increased after the first 30-minute foot stimulation via electrodes 1 and 2 but it was significantly increased a mean ± SE of 47.5% ± 2.9% after the second 30-minute stimulation via electrodes 1 and 3. After inducing the post-stimulation effect the foot stimulation applied during cystometrograms via electrodes 1 and 2 or 1 and 3 elicited a further increase in bladder capacity (mean 23.26% ± 17.64% and 20.07% ± 18.59%, respectively).

CONCLUSIONS

Results show that the transcutaneous plantar electrical stimulation of somatic afferent nerves in the foot can induce a post-stimulation increase in bladder capacity, suggesting that an intermittent stimulation pattern rather than continuous stimulation might be effective as clinical application to treat overactive bladder symptoms.

Irritation induced bladder overactivity is suppressed by tibial nerve stimulation in cats

PURPOSE

We investigated the effects of tibial nerve stimulation on bladder overactivity induced by acetic acid irritation.

MATERIALS AND METHODS

Cystometry was performed in 10 α-chloralose anesthetized female cats by infusing saline or acetic acid through a urethral catheter that was secured by a ligature around the urethra. Intravesical infusion of 0.25% acetic acid was used to irritate the bladder and induce bladder overactivity. Multiple cystometrograms were done before, during and after tibial nerve stimulation to determine the inhibitory effect on the micturition reflex.

RESULTS

Infusion of 0.25% acetic acid irritated the bladder, induced bladder overactivity and significantly decreased bladder capacity to about 20% of control capacity measured during saline infusion. Tibial nerve stimulation at low (5 Hz) or high (30 Hz) frequency significantly increased bladder capacity to about 40% of saline control capacity when it was applied during acetic acid infusion cystometrogram. Bladder contraction amplitude was smaller during acetic acid irritation than during saline distention due to significantly smaller bladder capacity. Tibial nerve stimulation at 5 Hz increased bladder capacity and bladder contraction amplitude.

CONCLUSIONS

Activation of somatic afferents in the tibial nerve of cats can partially reverse the bladder overactivity induced by intravesical administration of a chemical irritant that activates C-fiber afferent nerves. These data are consistent with clinical studies showing that tibial nerve neuromodulation is effective treatment for overactive bladder symptoms.

Posterior tibial nerve stimulation and faecal incontinence: a review

PURPOSE

Faecal incontinence is a common and important multifactorial disorder with a range of treatment options. Over the last two decades, neuromodulation via sacral nerve stimulators has been shown to be effective for both faecal and urinary incontinence, although associated with complications. Peripheral neuromodulation, via the posterior tibial nerve, is widely used in urinary incontinence; however, its use in faecal incontinence, whilst evolving is limited to eight small heterogeneous studies.

REVIEW

These eight studies are discussed in the context of the methodology and underlying neurophysiology of peripheral neuromodulation, as are thus far unanswered questions. The eight studies include a total of 129 patients with faecal incontinence (of variable aetiology), all of whom had failed conservative management. One study was prospective and controlled, six were uncontrolled and one was retrospective and uncontrolled. Five different neuromodulatory protocols were used over six different study periods. Outcome measures varied, but short term primary endpoint success ranged from 30.0% to 83.3%. The limitations to this early evidence, whilst encouraging, are significant, and it remains to be seen whether this novel treatment modality represents the minimally invasive, well-tolerated, cost-effective and flexible panacea hoped for this common and debilitating disease. Three upcoming multicentre placebo-controlled trials will better be able to delineate its role.

Suppression of bladder overactivity by activation of somatic afferent nerves in the foot

OBJECTIVE

To investigate the possibility of suppressing bladder overactivity by electrical activation of somatic afferent nerves in the foot.

MATERIALS AND METHODS

Cats with an intact spinal cord were studied under α-chloralose anaesthesia. Bladder pressure was recorded via a urethral catheter. Foot stimulation was applied via surface pad electrodes attached to the skin of the front or hind foot.

RESULTS

Reflex micturition was inhibited by electrical stimulation of the hind foot at either low (5 Hz) or high (20 Hz) frequencies, but stimulation of the front foot was ineffective. The mean (sem) bladder capacity during a saline infusion cystometrogram (CMG) was significantly (P < 0.05) increased to 153.2 (18.2)% and 136.9 (14.3)% of the control bladder capacity by stimulation at frequencies of 5 Hz and 20 Hz, respectively. Intravesical infusion of 0.25% acetic acid (AA) induced bladder overactivity and reduced bladder capacity to 20.3 (8.9)% of the control capacity measured during saline infusion. Foot stimulation inhibited the AA-induced bladder overactivity recorded under isovolumetric conditions, and significantly (P < 0.05) increased bladder capacity during AA infusion. However, it only restored the small bladder capacity caused by AA irritation to 40-50% of the control bladder capacity measured during saline infusion. The effect of foot stimulation did not persist after termination of stimulation during repeated CMG tests.

CONCLUSIONS

This study shows the potential of noninvasive transcutaneous electrical stimulation of somatic nerves in the foot to inhibit reflex bladder activity and treat overactive bladder symptoms.

Prolonged poststimulation inhibition of bladder activity induced by tibial nerve stimulation in cats

Inhibition of bladder activity by tibial nerve stimulation was investigated in α-chloralose-anesthetized cats with an intact spinal cord. Short-duration (3-5 min) tibial nerve stimulation at both low (5 Hz) and high (30 Hz) frequencies applied repeatedly during rhythmic isovolumetric bladder contractions was effective in inhibiting reflex bladder activity. Both frequencies of stimulation were also effective in inducing inhibition that persisted after the termination of the stimulation. The poststimulation inhibitory effect induced by the short-duration stimulation significantly increased bladder capacity to 181.6 ± 24.36% of the control capacity measured before applying the stimulation. Thirty-minute continuous stimulation induced prolonged poststimulation inhibition of bladder activity, which lasted for more than 2 h and significantly increased bladder capacity to 161.1 ± 2.9% of the control capacity. During the poststimulation periods, 5-Hz stimulation applied during the cystometrogram elicited a further increase (~30% on average) in bladder capacity, but 30-Hz stimulation was ineffective. These results in cats support the clinical observation that tibial nerve neuromodulation induces a long-lasting poststimulation inhibitory effect that is useful in treating overactive bladder symptoms.

Posterior tibial nerve stimulation for faecal incontinence

Faecal incontinence is a common multifactorial condition with a range of invasive treatment options, all of which may be associated with significant complications. Posterior tibial stimulation by continence nurses is an established treatment for urinary incontinence; however, its use in faecal incontinence, while rapidly evolving, is limited to eight small and differing studies. In this article, the background of current management options for faecal incontinence is discussed, as are the physiology and evidence underlying neuromodulation. The evidence base for posterior tibial nerve stimulation in faecal incontinence is reviewed, as well as the implications for practice and further research. While this early evidence base is encouraging, it has yet to be established whether this novel approach may be the minimally invasive, effective and cheap treatment hoped for, for this common and debilitating condition.

Peripheral neuromodulation via posterior tibial nerve stimulation - a potential treatment for faecal incontinence?

INTRODUCTION

Faecal incontinence is a prevalent and important condition, with a range of treatment options. Neuromodulation via sacral nerve stimulators is efficacious, but expensive and associated with complications due to device implantation. Peripheral neuromodulation via posterior tibial nerve stimulation (PTNS) has been assessed in urinary incontinence, but there is minimal evidence for its use in faecal incontinence and no literature from the UK. This retrospective review aimed to assess the efficacy of PTNS in faecal incontinence.

PATIENTS AND METHODS

Thirteen consecutive female patients with faecal incontinence of various causes (9 idiopathic, 3 obstetric, 1 surgery) underwent PTNS at a UK hospital. All were investigated with colonic imaging, anorectal physiology and endo-anal ultrasound. Prior treatments included physiotherapy (13), sphincteroplasty (3) biofeedback (3) and PTQ implants (1). PTNS was performed for 30 min, weekly for 12 weeks.

RESULTS

Median monthly episodes of incontinence of wind, liquid and solid reduced from 6, 10 and 18 respectively to 0 with 12 weeks' treatment (P < 0.05). Significant improvements in quality of life indices were also seen. At 1-month follow up, a sustained reduction in incontinence of wind was seen (0 episodes), with non-significant reductions of liquid and solid stool.

CONCLUSIONS

PTNS is a potentially efficacious, technically simple and minimally invasive alternative treatment modality for faecal incontinence. These early results are encouraging, but we await medium- and long-term follow-up, and a larger randomised trial comparing PTNS with alternative treatments and placebo.

Transcutaneous posterior tibial nerve stimulation for fecal incontinence in inflammatory bowel disease patients: a therapeutic option?

BACKGROUND

Fecal incontinence associated with inflammatory bowel disease (IBD) may be particularly difficult to treat. Two recent studies showed that transcutaneous posterior tibial nerve stimulation may improve fecal continence. In this pilot study, we tested the usefulness of this noninvasive technique to treat fecal incontinence in IBD.

METHODS

Twelve patients with IBD (7 Crohn's disease, 2 undetermined colitis, 3 ulcerative colitis) were treated by applying transcutaneous posterior tibial nerve electrical stimulation daily for 3 months. A clinical evaluation was performed at the end of treatment, with Wexner's score and Harvey-Bradshaw index and analog scales to assess symptoms and quality of life.

RESULTS

At 3 months, 5 patients (41.6%) reported a significant symptomatic and quality of life improvement, although only 1 reported a significant modification in the Wexner score.

CONCLUSION

These preliminary results are encouraging, although further studies are necessary. Posterior tibial nerve electrical stimulation may represent a new therapeutic option to treat the difficult problem of fecal incontinence in patients with IBD.