Long-term outcome of sacral neuromodulation for chronic refractory constipation

Sacral Neuromodulation for defecation disorders after non oncologic pelvic surgery

PURPOSE

Defecation disorders (DD) can sometimes affect the outcomes of pelvic or colorectal surgery. The aim of the present study is to evaluate the role of sacral neuromodulation for the treatment of constipation and other evacuation disorders after surgery.

METHODS

A retrospective analysis in all the consecutive patients that underwent sacral nerve modulation (SNM) for DD arisen or worsened after pelvic or colorectal surgery was performed from January 2010 to December 2020. DD were defined starting from Rome IV Criteria, and according to manometric results, all patients were further divided into the two subgroups: inadequate defecatory propulsion and dyssynergic defecation. Cleveland Clinic Constipations Score (CCCS) and SF-36 have been evaluated in the time.

RESULTS

Thirty-seven patients have been included in the study. Twenty-seven out of thirty-seven (73.3%) patients had experienced sufficient benefits to implant the definitive device, and 22 patients (59.4% of tested and 81.5% of permanently implanted) still had the device functioning after a mean follow-up of 6.3 years. The most represented manometric pattern was inadequate propulsive function (59% of patients). CCCS at preoperative assessment for all patients was 17.5 with a reduction to 10.4 at the first year of follow-up (p < 0.001).

CONCLUSION

SNM appears to be a feasible, safe, and well-tolerated procedure with durable benefit in the long-term treatment of defecatory dysfunction after pelvic or colorectal surgery for benign diseases.

Regulation of enteric nervous system via sacral nerve stimulation in opioid-induced constipated rats

Objectives

Sacral nerve stimulation (SNS) has been employed for treating constipation. However, its mechanisms involving enteric nervous system (ENS) and motility are largely unknown. In this study, we investigated the possible ENS involvement of SNS in treating Loperamide-induced constipation in rats.

Methods

Experiment-1 was designed to study the effects of acute SNS on whole colon transit time (CTT). In experiment-2, we induced constipation by Loperamide and then applied daily SNS or sham-SNS for 1 week. Choline acetyltransferase (ChAT), nitric oxide synthase (nNOS), and PGP9.5 in colon tissue were examined at the end of the study. Moreover, survival factors such as phosphorylated AKT (p-AKT) and Glial cell-derived neurotrophic factor (GDNF) were measures by immunohistochemistry (IHC) and western blot (WB).

Key results

(1) SNS with one set of parameters shortened CTT starting at 90 min after phenol red administration (p < 0.05). (2) While Loperamide induced slow transit constipation with a significant reduction in fecal pellet number and feces wet weight, daily SNS for a week resolved constipation. (3) Moreover, SNS was able to shorten whole gut transit time comparing to sham-SNS (p = 0.01). (4) Loperamide reduced the number of PGP9.5 and ChAT positive cells, and downregulated ChAT protein expression and upregulated nNOS protein expression, whereas these detrimental effects were significantly reversed by SNS. (5) Furthermore, SNS increased expressions of both GDNF and p-AKT in colon tissue. (6) Vagal activity was reduced following Loperamide (p < 0.01); yet SNS normalized vagal activity.

Conclusion

SNS with appropriate parameters improves opioid-induced constipation and reversed the detrimental effects of Loperamide on enteric neurons possibly via the GDNF-PI3K/Akt pathway.GRAPHICAL ABSTRACT.

[Sacral Neuromodulation for Fecal Incontinence and Constipation: Evidence, Programming and Long-term Management]

BACKGROUND

Over the last two decades, sacral neuromodulation (SNM) has established its role in the treatment of functional pelvic organ-/pelvic floor disorders. Even though the mode of action is not fully understood, SNM has become the preferred surgical treatment of fecal incontinence.

METHODS AND RESULTS

A literature search was carried out on programming sacral neuromodulation and long-term outcomes in treating fecal incontinence and constipation.Sacral neuromodulation was found to be successful in the long term. Over the years, the spectrum of indications has expanded, and now includes patients presenting with anal sphincter lesions. The use of SNM for low anterior resection syndrome (LARS) is currently under clinical investigation. Findings of SNM for constipation are less convincing. In several randomised crossover studies, no success was demonstrated, even though it is possible that subgroups may benefit from the treatment. Currently the application cannot be recommended in general.The pulse generator programming sets the electrode configuration, amplitude, pulse frequency and pulse width. Usually pulse frequency and pulse width follow a default setting (14 Hz, 210 s), while electrode configuration and stimulation amplitude are adjusted individually to the patient need and perception of stimulation.Despite low infection rates and few electrode-/pulse generator dysfunctions, up to 65% of patients require surgical reintervention during long term follow-up - in 50% of cases because of battery depletion, which is an expected event. At least one reprogramming is necessary in about 75% of the patients during the course of the treatment, mostly because of changes in effectiveness, but rarely because of pain. Regular follow-up visits appear to be advisable.

CONCLUSION

Sacral neuromodulation can be considered to be a safe and effective long-term therapy of fecal incontinence. To optimise the therapeutic effect, a structured follow-up regime is advisable.

ACG Clinical Guidelines: Management of Benign Anorectal Disorders

Benign anorectal disorders of structure and function are common in clinical practice. These guidelines summarize the preferred approach to the evaluation and management of defecation disorders, proctalgia syndromes, hemorrhoids, anal fissures, and fecal incontinence in adults and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence for these guidelines was assessed using the Grading of Recommendations Assessment, Development and Evaluation process. When the evidence was not appropriate for Grading of Recommendations Assessment, Development and Evaluation, we used expert consensus to develop key concept statements. These guidelines should be considered as preferred but are not the only approaches to these conditions.

The role of neuromodulation in chronic functional constipation: a systematic review

BACKGROUND

Chronic functional constipation is a highly prevalent disorder in which, when conservative measures fail to relieve symptoms, surgical interventions are sometimes indicated. In recent years, neuromodulation for the treatment of functional constipation has gained interest but its role and effectiveness are still unclear. The purpose of this review is to provide a systematic overview on the current literature on the different modalities of neurostimulation and their effect on chronic functional constipation in adults as reported in the literature.

METHODS

A search in the literature for articles concerning the effect of different types of neuromodulation on constipation was performed in PubMed using extensive search terms for the different modalities of neuromodulation. Studies and trials were checked for eligibility. For all types of neuromodulation together, 27 articles were included.

RESULTS

17 studies were included on SNM (sacral nerve modulation). Although multiple studies show positive results on the effect of SNM in constipation, double-blind crossover RCT's (randomised controlled trials) showed no significant effect. 3 studies were included for tSNS (transcutaneous sacral nerve stimulation), 2 for PTNS (percutaneous tibial nerve stimulation) and 2 for TTNS (transcutaneous tibial nerve stimulation). Studies and trials on these modalities of neuromodulation reported ambiguous results on statistical significance of the effect. For transcutaneous IFC (interferential current therapy) 2 studies were included, which both reported a statistically significant effect on all outcomes.

CONCLUSION

The beneficial effect of neuromodulation in chronic functional constipation remains questionable. However, neuro-modulation might be worth considering in patients refractory to treatment before turning to more invasive measures. Future research should shed more light on the effects of neuromodulation in constipation.

Electroacupuncture vs Prucalopride for Severe Chronic Constipation: A Multicenter, Randomized, Controlled, Noninferiority Trial

INTRODUCTION

This multicenter, randomized, noninferiority trial compared electroacupuncture with prucalopride for the treatment of severe chronic constipation (SCC).

METHODS

Participants with SCC (≤ 2 mean weekly complete spontaneous bowel movements [CSBMs]) were randomly assigned to receive either 28-session electroacupuncture over 8 weeks with follow-up without treatment over 24 weeks or prucalopride (2 mg/d before breakfast) over 32 weeks. The primary outcome was the proportion of participants with ≥3 mean weekly CSBMs over weeks 3-8, based on the modified intention-to-treat population, with -10% as the noninferior margin.

RESULTS

Five hundred sixty participants were randomized, 280 in each group. Electroacupuncture was noninferior to prucalopride for the primary outcome (36.2% vs 37.8%, with a difference of -1.6% [95% confidence interval, -8% to 4.7%], P < 0.001 for noninferiority); almost the same results were found in the per-protocol population. The proportions of overall CSBM responders through weeks 1-8 were similar in the electroacupuncture and prucalopride groups (24.91% vs 25.54%, with a difference of -0.63% [95% confidence interval, -7.86% to 6.60%, P = 0.864]). Except during the first 2-week treatment, no between-group differences were found in outcomes of excessive straining, stool consistency, and quality of life. Adverse events occurred in 49 (17.69%) participants in the electroacupuncture group and 123 (44.24%) in the prucalopride group. One non-treatment-related serious adverse event was recorded in the electroacupuncture group.

DISCUSSION

Electroacupuncture was noninferior to prucalopride in relieving SCC with a good safety profile. The effects of 8-week electroacupuncture could sustain for 24 weeks after treatment. Electroacupuncture is a promising noninferior alternative for SCC (see Visual Abstract, http://links.lww.com/AJG/B776).

Auricular Vagal Nerve Stimulation Improves Constipation by Enhancing Colon Motility via the Central-Vagal Efferent Pathway in Opioid-Induced Constipated Rats

OBJECTIVES

Constipation and opioid-induced constipation (OIC) are common with limited treatment options. We investigated whether a noninvasive method of auricular vagal nerve stimulation (aVNS) could be used for treating OIC and explored its potential mechanisms and neural pathways in a rodent model of OIC.

MATERIALS AND METHODS

Sprague-Dawley were chronically implanted with one pair of auricular electrodes for aVNS. Sixteen rats were treated with loperamide for a week while another 16 rats received bilateral vagotomy, then randomly treated with aVNS or sham-aVNS for a week. In addition, eight normal rats were implanted with a polyethylene catheter in the proximal colon for assessing whole colon transit.

RESULTS

1) The number of fecal pellets and water content in feces increased after aVNS, compared with sham-aVNS. 2) aVNS accelerated colon transit and whole gut transit, compared with sham-aVNS. 3) In colon tissues, aVNS increased the protein expression of choline acetyltransferase, glial cell line-derived neurotrophic factor and the c-kit expression in myenteric interstitial cells of Cajal but decreased the protein expression of neural nitric oxide synthase (p < 0.05 for all, vs. sham-VNS). 4) The prokinetic effects of aVNS were abolished by both subdiaphragmatic vagotomy and atropine. 5) aVNS increased the c-fos expression in both nucleus tractus solitarius and dorsal motor nucleus of vagus, and increased vagal efferent activity (p < 0.05, vs. sham-VNS).

CONCLUSIONS

aVNS improves OIC by enhancing colon motility and restoring enteric neural functions mediated via the central and vagal efferent pathway.

Effects of temporary sacral nerve stimulation on gastrointestinal motility and function in patients with chronic refractory slow-transit constipation

BACKGROUND

The efficacy of sacral nerve stimulation (SNS) on patients with chronic refractory slow-transit constipation is controversial and its mechanism of action on gastrointestinal motility and transit is not fully understood. The aim of this study was to document the effects of temporary SNS on the gastrointestinal and biliary tract motility and on gastrointestinal transit in patients with refractory slow-transit constipation.

METHODS

This was a prospective interventional study. Patients with slow-transit chronic constipation, unresponsive to any conservative treatment, were enrolled between January 2013 and December 2018. Patients' quality of life [patient assessment of constipation quality of life (PAC-QOL) questionnaire], constipation scores (Cleveland Clinic Constipation Score) colonic transit time (CTT), orocecal transit time (OCTT), gastric and gallbladder kinetics, together with the assessment of the autonomic nerve function were evaluated before and during temporary SNS.

RESULTS

14 patients (12 females, median age 38 years, range 24-42 years) had temporary SNS. The Cleveland Clinic Constipation Score did not change compared to baseline (23 ± 3 vs 21.4; p = 070). The PAC-QOL did not improve significantly during the stimulation period. Gallbladder/stomach motility (half-emptying time) did not change significantly before and after SNS. OCTT was delayed at baseline, as compared to standard internal normal values, and did not change during SNS. CTT did not improve significantly, although in two patients it decreased substantially from 97 to 53 h, and from 100 to 65 h.

CONCLUSIONS

Temporary SNS did not have any effect on upper/lower gastrointestinal motility and transit in patients with severe constipation.

Comparison of long-term outcome of sacral nerve stimulation for constipation and faecal incontinence with focus on explantation rate, additional visits, and patient satisfaction

BACKGROUND

The aim of the present study was to compare sacral nerve stimulation (SNS) for constipation (SNS-C) with SNS for idiopathic faecal incontinence (SNS-IFI) regarding explantation rate, additional visits, and improvement of patient satisfaction 5 years after implantation.

METHODS

From our prospective database (launched in 2009), we extracted all SNS-C patients 5 years post-implantation, and the SNS-IFI patients implanted just before and just after each SNS-C patient. We retrospectively evaluated the explantation rate, number of additional visits, and patient satisfaction using a visual analogue scale (VAS). We hypothesized that compared with those in the SNS-IFI group: (1) the explantation rate would be higher in SNS-C patients, (2) the number of additional visits would be higher in SNS-C patients, and (3) in patients with an active implant at 5 years, the improvement in VAS would be the same.

RESULTS

We included 40 SNS-C patients and 80 SNS-IFI patients. In the SNS-C group 7/40 (17.5%), patients were explanted, compared to 10/80 (12.5%) patients in the SNS-IFI group (p = 0.56). The mean number of additional visits in the SNS-C group was 3.5 (95% CI 2.8-4.1)) and 3.0 (95% CI 2.6-3.6)) in the SNS-IFI group (p = 0.38). Additional visits due to loss of efficacy were significantly higher in the SNS-C patients (p = 0.03). The reduction in VAS score (delta VAS) at 5 years was 37.1 (95% CI 20.9-53.3) in the SNS-C group, and 46.0 (95% CI 37.9-54.0) in the SNS-IFI group (p = 0.27).

CONCLUSIONS

No significant difference was found regarding explantation rate, number of additional visits, or improvement of VAS at 5 years after SNS implantation between SNS-C patients and SNS-IFI patients.

Sacral nerve stimulation increases gastric accommodation in rats: a spinal afferent and vagal efferent pathway

Impaired gastric accommodation (GA) has been frequently reported in various gastrointestinal diseases. No standard treatment strategy is available for treating impaired GA. We explored the possible effect of sacral nerve stimulation (SNS) on GA and discovered a spinal afferent and vagal efferent mechanism in rats. Sprague-Dawley rats (450-500 g) with a chronically implanted gastric cannula and ECG electrodes were studied in a series of sessions to study: 1) the effects of SNS with different parameters on gastric tone, compliance, and accommodation using a barostat device; two sets of parameters were tested as follows: parameter 1) 5 Hz, 500 µs, 10 s on 90 s off; 90% motor threshold and parameter 2) same as parameter 1 but 25 Hz; 2) the involvement of spinal afferent pathway via detecting c-fos immunoreactive (IR) cells in the nucleus of the solitary tract (NTS) of the brain; 3) the involvement of vagal efferent activity via the spectral analysis of heart rate variability derived from the ECG; and 4) the nitrergic mechanism, N^ω-nitro-l-arginine methyl ester (l-NAME), a nitric oxide synthase (NOS) inhibitor, was given before SNS at 5 Hz. Compared with sham-SNS: 1) SNS at 5 Hz inhibited gastric tone and increased gastric compliance and GA. No difference was noted between the stimulation frequencies of 5 and 25 Hz. 2) SNS increased the expression of c-fos in the NTS. 3) SNS increased cardiac vagal efferent activity and decreased the sympathovagal ratio. 4) l-NAME blocked the relaxation effect of SNS. In conclusion, SNS with certain parameters relaxes gastric fundus and improves gastric accommodation mediated via a spinal afferent and vagal efferent pathway.NEW & NOTEWORTHY Currently, there is no adequate medical therapy for impaired gastric accommodation, since medications that relax the fundus often impair antral peristalsis and thus further delay gastric emptying that is commonly seen in patients with functional dyspepsia or gastroparesis. The advantage of the potential sacral nerve stimulation therapy is that it improves gastric accommodation by enhancing vagal activity, and the enhanced vagal activity would lead to enhanced antral peristalsis rather than inhibiting it.

Management of functional constipation in children and adults

Functional constipation is common in children and adults worldwide. Functional constipation shows similarities in children and adults, but important differences also exist regarding epidemiology, symptomatology, pathophysiology, diagnostic workup and therapeutic management. In children, the approach focuses on the behavioural nature of the disorder and the initial therapeutic steps involve toilet training and laxatives. In adults, management focuses on excluding an underlying cause and differentiating between different subtypes of functional constipation - normal transit, slow transit or an evacuation disorder - which has important therapeutic consequences. Treatment of adult functional constipation involves lifestyle interventions, pelvic floor interventions (in the presence of a rectal evacuation disorder) and pharmacological therapy. When conventional treatments fail, children and adults are considered to have intractable functional constipation, a troublesome and distressing condition. Intractable constipation is managed with a stepwise approach and in rare cases requires surgical interventions such as antegrade continence enemas in children or colectomy procedures for adults. New drugs, including prokinetic and prosecretory agents, and surgical strategies, such as sacral nerve stimulation, have the potential to improve the management of children and adults with intractable functional constipation.

Placebo Response Rates in Electrical Nerve Stimulation Trials for Fecal Incontinence and Constipation: A Systematic Review and Meta-Analysis

BACKGROUND

Successful treatments following electrical nerve stimulation have been commonly reported in patients with fecal incontinence and constipation. However, many of these nerve stimulation trials have not implemented sham controls, and are, therefore, unable to differentiate overall treatment responses from placebo. This systematic review aimed to quantify placebo effects and responses following sham electrical nerve stimulation in patients with fecal incontinence and constipation.

MATERIAL AND METHODS

A literature search of Ovid MEDLINE, PubMed, EMBASE, and Cochrane databases was conducted from inception to April 2017. Randomized sham-controlled trials investigating the effect of lower gastrointestinal electrical nerve stimulation in fecal incontinence and constipation were included. Pediatric and non-sham controlled trials were excluded.

RESULTS

Ten randomized sham-controlled trials were included. Sham stimulation resulted in improvements in fecal incontinence episodes by 1.3 episodes per week (95% CI -2.53 to -0.01, p = 0.05), fecal urgency by 1.5 episodes per week (CI -3.32 to 0.25, p = 0.09), and Cleveland Clinic Severity scores by 2.2 points (CI 1.01 to 3.36, p = 0.0003). Sham also improved symptoms of constipation with improved stool frequency (1.3 episodes per week, CI 1.16 to 1.42, p < 0.00001), Wexner Constipation scores (5.0 points, CI -7.45 to -2.54 p < 0.0001), and Gastrointestinal Quality of Life scores (7.9 points, CI -0.46 to 16.18, p = 0.06).

CONCLUSIONS

Sham stimulation is associated with clinical and statistically meaningful improvements in symptoms of fecal incontinence and constipation, as well as quality of life scores, highlighting the importance of sham controls in nerve stimulation trials. Noncontrolled studies should be interpreted with caution.

Sacral nerve stimulation with appropriate parameters improves constipation in rats by enhancing colon motility mediated via the autonomic-cholinergic mechanisms

Although sacral nerve stimulation (SNS) has been applied for treating constipation, its parameters were adopted from SNS for fecal incontinence, its effects are limited, and mechanisms are largely unknown. We investigated the effects and mechanism of SNS with appropriate parameters on constipation in rats treated with loperamide. First, using rectal compliance as an outcome measure, an experiment was performed to derive effective SNS parameters. Then, a 7-day SNS was performed in rats with constipation induced by loperamide. Autonomic functions were assessed by spectral analysis of heart rate variability (HRV) derived from an electrocardiogram. Serum levels of pancreatic polypeptide (PP), norepinephrine (NE), and acetylcholine (ACh) in colon were assessed. 1) Acute SNS at 5 Hz, 100 µs was found effective in enhancing rectal compliance and accelerating distal colon transit (P < 0.05 vs. sham SNS). 2) The 7-day SNS normalized loperamide-induced constipation, assessed by the number, weight, and water content of fecal pellets, and accelerated the distal colon transit (29.4 ± 3.7 min with sham SNS vs. 16.4 ± 5.3 min with SNS but not gastric emptying or intestinal transit. 3) SNS significantly increased vagal activity (P = 0.035) and decreased sympathetic activity (P = 0.012), assessed by spectral analysis of HRV as well as by the serum PP. 4) SNS increased ACh in the colon tissue; atropine blocked the accelerative effect of SNS on distal colon transit. We concluded that SNS with appropriate parameters improves constipation induced by loperamide by accelerating distal colon motility, mediated via the autonomic-cholinergic function.NEW & NOTEWORTHY Although sacral nerve stimulation (SNS) has been applied for treating constipation, its parameters were adopted from SNS for fecal incontinence, effects are limited, and mechanisms are largely unknown. This paper shows that SNS with appropriate parameters improves constipation induced by loperamide by accelerating distal colon motility mediated via the autonomic-cholinergic function.

Sacral nerve stimulation in slow-transit constipation: effectiveness at 5-year follow-up

AIM

The aim of this study is to evaluate the short- and long-term efficacy of sacral nerve stimulation (SNS) for treating slow-transit constipation (STC).

METHOD

This is a retrospective cohort analysis of the efficacy of SNS in treating patients affected by STC, who previously failed to respond to conservative therapies. Only patients free of concomitant diseases were enrolled in our study. A temporary stimulation lead was initially implanted; patients with a > 50% symptom reduction were eventually deemed eligible for a permanent implant.

RESULTS

This study enrolled 25 patients who underwent a SNS test stimulation; 21 patients (13 women; median age 32 years) eventually got a permanent implant. The median preoperative Cleveland Clinic Constipation Score (CCCS) was 21 (16-25). Preoperative colorectal transit time recorded a median of 10 markers (7-19) retained in the colorectal tract. At 6-month postoperative follow-up, the total number of markers retained in the colorectal tract decreased to 3 (0-4). The CCCS score improved during the first postoperative year (P < 0.001), but progressively worsened over the longer term. The SF-36 questionnaire showed an improvement in all 8 scales measuring physical and psycho-emotional states; all parameters recorded into the bowel diary also improved. Overall, at 60-month follow up, the overall neuromodulator removal rate was 48%.

CONCLUSIONS

The SNS is a minimally invasive surgical procedure that we tested for treating STC. The short-term outcome was promisingly after 6 months; however, there was a declining trend beyond this interval. Thus, the long-term efficacy of SNS needs to be further assessed.

Physicochemical properties and laxative effects of polysaccharides from Anemarrhena asphodeloides Bge. in loperamide-induced rats

ETHNOPHARMACOLOGICAL RELEVANCE

As a traditional Chinese herbal medicine, Anemarrhena asphodeloides Bge. possesses the effects of nourishing yin, moistening dryness, clearing lungs and relieving fire. Simultaneously, it has been used to treat constipation for more than one thousand years in China. However, modern medical studies are limited and lacking on its therapeutic mechanism.

AIM OF THE STUDY

This current study was aimed to investigate the laxative activities and explore the potential mechanism of Anemarrhena asphodeloides Bge. polysaccharides (AABP) in loperamide-induced constipation rats.

MATERIALS AND METHODS

The structure of AABP was determined by using infrared spectrum, high performance gel permeation chromatography (HPGPC), and high performance liquid chromatography (HPLC). Real-time quantitative polymerase chain reaction (PCR), multitudinous methods were adopted to explore the underlining therapeutic mechanism of AABP in treating constipation, including enzyme-linked immunosorbent assay (ELISA), histopathological, immunohistochemistry and western blotting.

RESULTS

In the present study, the average molecular weight of AABP was determined as 1.11 × 10³ kDa. The primary monosaccharide compositions were analyzed including D-mannose, L-rhamnose, D-galacturonic acid, D-glucose, D-galactose and L-arabinose (1, 0.04, 0.53, 0.11, 0.33, 0.25, respectively) by high-performance liquid chromatography (HPLC). AABP significantly increased the levels of gastrin (Gas), motilin (MTL), substance P (SP), 5-hydroxytryptamine (5-HT) and vasoactive intestinal peptide (VIP), and decreased the NO content of loperamide-induced rats to ameliorate constipation in the rats. Whilst, AABP repaired the damaged colons by regulating PCNA and ICAM-1 protein expressions. Additionally, AABP up-regulated the levels of SCF, c-Kit, AQP3 and VIP as well as down-regulated the expressions of AQP8, AQP4 and PGE2.

CONCLUSION

The present findings suggested that AABP were the laxative active ingredients isolated from Anemarrhena asphodeloides Bge., which could treat constipation through regulating the gastrointestinal hormones and neurotransmitters to improve the intestinal motility and water metabolism.

Sacral nerve stimulation for constipation: long-term outcomes

BACKGROUND

There has been some controversy regarding the efficacy of sacral nerve stimulation (SNS) for the treatment of chronic constipation, due to less positive outcomes and concerns about cost-effectiveness in the long term. The aim of the present study was to evaluate the long-term outcomes of SNS in patients with chronic constipation.

METHODS

A retrospective study was conducted on patients who had SNS for chronic constipation in 2008-2017 at our institution. Clinical factors, profile of constipation, physiology studies, and patient satisfaction with SNS therapy were investigated during a follow-up period up to 10 years after the implantation.

RESULTS

Twenty-nine patients [86% female, median age 49 years (range 17-86)] were tested for SNS, and 24 received implants after a positive test phase [median 47 days (range 21-56 days)]. There were 27 bilateral and 2 unilateral implants, in S3 or S4 depending on best response. Mean follow-up was 59 months. Efficacy was considered as a score > 5 (on a scale of 1-10) in general symptom improvement. Nine (37.9%) implanted patients had a satisfaction score > 5. In 6 cases (25%), patient satisfaction was higher than 9. Due to the small sample size, there were no statistically significant variables considered as predictors of response.

CONCLUSIONS

Our results agree with current studies which describe around a 30% response of SNS for refractory constipation. However, there is a small group of patients highly satisfied with SNS therapy. More studies are needed to better understand this profile and optimize outcomes.

Success and Complication Rates After Sacral Neuromodulation for Fecal Incontinence and Constipation: A Single-center Follow-up Study

Background/Aims

The aim of this study was to evaluate the sustainability of sacral neuromodulation (SNM) success in patients with fecal incontinence (FI) and/or constipation.

Methods

This is a retrospective analysis of a prospective database of patients who received SNM therapy for FI and/or constipation between 2006 and 2015. Success rates, complications and reintervention rates were assessed after up to 10 years of follow-up.

Results

Electrodes for test stimulation were implanted in 101 patients, of whom 79 (78.2%) received permanent stimulation. The mean follow-up was 4.4 ± 3.0 years. At the end of follow-up, 57 patients (72.2%) were still receiving SNM. The 5-year success rate for FI and isolated constipation was 88.2% (95% confidence interval [CI], 80.1-97.0%) and 31.2% (95% CI, 10.2-95.5%), respectively (P ＜ 0.001). In patients with FI, involuntary evacuations per week decreased ＞ 50% in 76.1% of patients (95% CI, 67.6-86.2%) after 5 years. A lead position at S3 was associated with an improved outcome (P = 0.04). Battery exchange was necessary in 23 patients (29.1%), with a median battery life of 6.2 years. Reinterventions due to complications were necessary in 24 patients (30.4%). For these patients, the 5-year success rate was 89.0% (95% CI, 75.3-100.0%) compared to 78.4% (95% CI, 67.2-91.4%) for patients without reintervention.

Conclusions

SNM offers an effective sustainable treatment for FI. For constipation, lasting success of SNM is limited and is thus not recommended. Reinterventions are necessary but do not impede treatment success.

Mapping the current flow in sacral nerve stimulation using computational modelling

Sacral nerve stimulation (SNS) is an established treatment for faecal incontinence involving the implantation of a quadripolar electrode into a sacral foramen, through which an electrical stimulus is applied. Little is known about the induced spread of electric current around the SNS electrode and its effect on adjacent tissues, which limits optimisation of this treatment. The authors constructed a 3-dimensional imaging based finite element model in order to calculate and visualise the stimulation induced current and coupled this to biophysical models of nerve fibres. They investigated the impact of tissue inhomogeneity, electrode model choice and contact configuration and found a number of effects. (i) The presence of anatomical detail changes the estimate of stimulation effects in size and shape. (ii) The difference between the two models of electrodes is minimal for electrode contacts of the same length. (iii) Surprisingly, in this arrangement of electrode and neural fibre, monopolar and bipolar stimulation induce a similar effect. (iv) Interestingly when the active contact is larger, the volume of tissue activated reduces. This work establishes a protocol to better understand both therapeutic and adverse stimulation effects and in the future will enable patient-specific adjustments of stimulation parameters.

Refractory Constipation: What is the Clinician to Do?

Most clinicians will agree that chronic constipation is characterized by abnormal bowel movement consistency and/or frequency plus or minus evacuation symptoms, but patient perception of constipation varies widely and includes symptoms that may or may not meet official defining criteria. Although intermittent constipation is extremely common, only a small minority of patients seek care for their symptoms. Among these patients, dissatisfaction with the currently available laxative options is not uncommon, and many patients will require specialized care for severe or refractory symptoms-especially those with abdominal pain, irritable bowel syndrome overlap, bloating or distention, and psychological comorbidities. This review outlines a physiological assessment of the patient with refractory constipation, exploring treatment options among patients with slow transit, rectal evacuation disorders, and normal transit. In addition, we explore nonlaxative approaches to normal-transit patients bothered by ongoing symptoms, with an emphasis on the biopsychosocial model of functional gastrointestinal disease and treatment of visceral hypersensitivity using neuromodulators. Finally, we propose a comprehensive evaluation algorithm for the management of patients with refractory slow-transit constipation considering surgery and examine surgical options including colectomy and cecostomy using an antegrade continent enema.

Percutaneous endoscopic colostomy for adults with chronic constipation: Retrospective case series of 12 patients

BACKGROUND

Percutaneous endoscopic colostomy (PEC) is a technique derived from percutaneous endoscopic gastrostomy. When conservative treatment of chronic obstipation fails, colon irrigation via PEC seems less invasive than surgical interventions. However, previous studies have noted high complication rates of PEC, mostly related to infections. Our aim was to report our experiences with PEC in patients with chronic refractory constipation.

METHODS

Retrospective analysis of all patients who underwent PEC for refractory constipation in our secondary referral hospital between 2009 and 2016.

KEY RESULTS

Twelve patients received a PEC for chronic, refractory constipation. Short-term efficacy for relief of constipation symptoms was good in 8 patients and moderate in 4 patients. Two patients had the PEC removed because of spontaneous improvement of constipation. Three patients, who initially noticed a positive effect, preferred an ileostomy over PEC after 1-5 years. One PEC was removed because of an abscess. Long-term efficacy is 50%: 6 patients still use their PEC after 3.3 years of follow-up. No mortality occurred.

CONCLUSIONS AND INTERFERENCES

PEC offers a technically easily feasible and safe treatment option for patients with chronic constipation not responding to conventional therapy. Long-term efficacy of PEC in our patients is 50%.

International Continence Society best practice statement for use of sacral neuromodulation

AIMS

Sacral neuromodulation (SNM) is an accepted therapy for a variety of conditions. However, despite over 20 years of experience, it remains a specialized procedure with a number of subtleties. Here we present the recommendations issued from the International Continence Society (ICS) SNM Consensus Panel.

METHODS

Under the auspices of the ICS, eight urologists, three colorectal surgeons and two urogynecologists, covering a wide breadth of geographic and specialty interest representation, met in January 2017 to discuss best practices for neuromodulation. Suggestions for statements were submitted in advance and specific topics were assigned to committee members, who prepared and presented supporting data to the group, at which time each topic was discussed in depth. Best practice statements were formulated based on available data. This document was then circulated to multiple external reviewers after which final edits were made and approved by the group.

RESULTS

The present recommendations, based on the most relevant data available in the literature, as well as expert opinion, address a variety of specific and at times problematic issues associated with SNM. These include the use of SNM for a variety of underlying conditions, need for pre-procedural testing, use of staged versus single-stage procedures, screening for success during the trial phase, ideal anesthesia, device implantation, post-procedural management, trouble-shooting loss of device function, and future directions for research.

CONCLUSIONS

These guidelines undoubtedly constitute a reference document, which will help urologists, gynecologists, and colorectal surgeons optimize their use of SNM for refractory urinary urgency and frequency, UUI, NOR, and FI.

Chronic constipation

Chronic constipation is a prevalent condition that severely impacts the quality of life of those affected. Several types of primary chronic constipation, which show substantial overlap, have been described, including normal-transit constipation, rectal evacuation disorders and slow-transit constipation. Diagnosis of primary chronic constipation involves a multistep process initiated by the exclusion of 'alarm' features (for example, unintentional weight loss or rectal bleeding) that might indicate organic diseases (such as polyps or tumours) and a therapeutic trial with first-line treatments such as dietary changes, lifestyle modifications and over-the-counter laxatives. If symptoms do not improve, investigations to diagnose rectal evacuation disorders and slow-transit constipation are performed, such as digital rectal examination, anorectal structure and function testing (including the balloon expulsion test, anorectal manometry or defecography) or colonic transit tests (such as the radiopaque marker test, wireless motility capsule test, scintigraphy or colonic manometry). The mainstays of treatment are diet and lifestyle interventions, pharmacological therapy and, rarely, surgery. This Primer provides an introduction to the epidemiology, pathophysiological mechanisms, diagnosis, management and quality of life associated with the commonly encountered clinical problem of chronic constipation in adults unrelated to opioid abuse.