Sacral nerve stimulation for the treatment of fecal incontinence

Review article: advances in the diagnosis and management of anorectal motility disorders

BACKGROUND

Anorectal motility disorders such as dyssynergic defecation (DD), faecal incontinence (FI) and anorectal pain affect 40% of the population and are a frequent reason for gastroenterology consultation. They significantly affect the quality of life and lead to psychological distress. Lack of understanding of these problems compounded by a lack of availability and knowledge of diagnostic tools in most medical centres and/or trained physicians has significantly hampered this field.

AIMS

To discuss the latest advances in pathophysiology, diagnostic tests and therapeutic options for these disorders using an evidence-based approach.

METHODS

We reviewed the published literature over the past 20 years on DD, FI and anorectal pain and distilled these into a narrative review.

RESULTS

A detailed history, prospective stool diary and digital rectal exam, together with diagnostic tests such as anorectal manometry, balloon expulsion test, translumbosacral anorectal magnetic stimulation test for assessing neuropathy, defecography and anal ultrasound, can provide detailed mechanistic and structural information. Such knowledge can pave the way for a meaningful and pathophysiologic-based management approach. This could include biofeedback therapy for DD or FI, sensory training for rectal hyposensitivity or sensory adaptation training for rectal hypersensitivity or sphincter bulking agents or neuromodulation therapies. These treatments are effective and safe.

CONCLUSIONS

Anorectal motility disorders are common, but either less well recognized or poorly managed by most gastroenterologists. Equipped with the practical and up-to-date knowledge provided in this review, physicians could provide improved health care for these patients.

Pleasurable and problematic receptive anal intercourse and diseases of the colon, rectum and anus

The ability to experience pleasurable sexual activity is important for human health. Receptive anal intercourse (RAI) is a common, though frequently stigmatized, pleasurable sexual activity. Little is known about how diseases of the colon, rectum, and anus and their treatments affect RAI. Engaging in RAI with gastrointestinal disease can be difficult due to the unpredictability of symptoms and treatment-related toxic effects. Patients might experience sphincter hypertonicity, gastrointestinal symptom-specific anxiety, altered pelvic blood flow from structural disorders, decreased sensation from cancer-directed therapies or body image issues from stoma creation. These can result in problematic RAI - encompassing anodyspareunia (painful RAI), arousal dysfunction, orgasm dysfunction and decreased sexual desire. Therapeutic strategies for problematic RAI in patients living with gastrointestinal diseases and/or treatment-related dysfunction include pelvic floor muscle strengthening and stretching, psychological interventions, and restorative devices. Providing health-care professionals with a framework to discuss pleasurable RAI and diagnose problematic RAI can help improve patient outcomes. Normalizing RAI, affirming pleasure from RAI and acknowledging that the gastrointestinal system is involved in sexual pleasure, sexual function and sexual health will help transform the scientific paradigm of sexual health to one that is more just and equitable.

Diagnostic tools for fecal incontinence: Scoring systems are the crucial first step

The main aim of this editorial is to comment on the recent article published by Garg et al in the World Journal of Gastroenterology 2023; 29: 4593-4603. This original research presents a new scoring system for fecal incontinence. Fecal incontinence is a chronic disease with a severe impact on the quality of life of the patients. Substantial social stigmatization often leads to significant underreporting of the condition even during visits to a specialist and could lead to further mismanagement or non-existent management of the disease. An important fact is that patients are often unable to describe their condition when not asked precisely defined questions. This problem is partially resolved by scoring questionnaires. Several scoring systems are commonly used; however, each of them has their shortcomings. For example, the absence of different kinds of leakage besides flatus and stool could further lead to underscoring the incontinence severity. Therefore, there has long been a call for a more precise scoring system. The correct identification of the presence and severity of fecal incontinence is paramount for further diagnostic approach and for choosing the appropriate therapy option. This editorial describes fecal incontinence, its effect on quality of life in general and further evaluates the diagnostic approach with a particular focus on symptom scoring systems and their implications for clinical practice.

Therapeutic potential and mechanisms of sacral nerve stimulation for gastrointestinal diseases

Background

The aim of this systemtic review is to introduce clinical applications (especially emerging) and potential mechanisms of sacral nerve stimulation (SNS) for treating various gastrointestinal diseases.

Materials and Methods

PubMed and Web of Science were searched for studies published on SNS and its clinical applications in fecal incontinence (limited to systematic review and meta-analysis of clinical studies), constipation (limited to reviews and randomized control clinical studies), irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and upper gastrointestinal motility disorders. The relevant studies were pooled, and their findings were summarized and discussed.

Results

SNS is an approved method for treating fecal incontinence. Systematic review and meta-analysis demonstrated high efficacy of the SNS therapy for fecal incontinence. Increased anal sphincter pressure and improvement in rectal sensation were reported as major mechanisms involved in the SNS therapy. SNS has also been proposed for treating constipation, but the therapy has been shown ineffective. There is a lack in SNS methodological optimization and mechanistic research. A few basic and clinical studies have reported the potential of SNS for treating visceral pain in IBS. SNS seemed capable of improving mucosal barrier functions. Several case reports are available in the literature on the treatment of IBD with SNS. Several laboratory studies suggested therapeutic potential of a special method of SNS for IBD. Cholinergic anti-inflammatory mechanisms were reported. Due to a recently reported spinal afferent and vagal efferent pathway of SNS, a few preclinical studies reported the potential of SNS for upper gastrointestinal motility disorders. However, no clinical studies have been performed.

Conclusions

SNS for fecal incontinence is a well-established clinical therapy. However, the current method of SNS is ineffective for treating constipation. Further methodological development and randomized clinical trials are needed to explore potential applications of SNS for IBS and IBD.

Mapping the peripheral nervous system in the whole mouse via compressed sensing tractography

Objective.The peripheral nervous system (PNS) connects the central nervous system with the rest of the body to regulate many physiological functions and is therapeutically targeted to treat diseases such as epilepsy, depression, intestinal dysmotility, chronic pain, and more. However, we still lack understanding of PNS innervation in most organs because the large span, diffuse nature, and small terminal nerve bundle fibers have precluded whole-organism, high resolution mapping of the PNS. We sought to produce a comprehensive peripheral nerve atlas for use in future interrogation of neural circuitry and selection of targets for neuromodulation.Approach.We used diffusion tensor magnetic resonance imaging (DT-MRI) with high-speed compressed sensing to generate a tractogram of the whole mouse PNS. The tractography generated from the DT-MRI data is validated using lightsheet microscopy on optically cleared, antibody stained tissue.Main results.Herein we demonstrate the first comprehensive PNS tractography in a whole mouse. Using this technique, we scanned the whole mouse in 28 h and mapped PNS innervation and fiber network in multiple organs including heart, lung, liver, kidneys, stomach, intestines, and bladder at 70µm resolution. This whole-body PNS tractography map has provided unparalleled information; for example, it delineates the innervation along the gastrointestinal tract by multiple sacral levels and by the vagal nerves. The map enabled a quantitative tractogram that revealed relative innervation of the major organs by each vertebral foramen as well as the vagus nerve.Significance.This novel high-resolution nerve atlas provides a potential roadmap for future neuromodulation therapies and other investigations into the neural circuits which drive homeostasis and disease throughout the body.

A systematic review of clinical studies on electrical stimulation therapy for patients with neurogenic bowel dysfunction after spinal cord injury

BACKGROUND

This study aimed to perform a systematic literature review of the clinical trial evidence on electrical stimulation for the treatment of neurogenic bowel dysfunction (NBD) after spinal cord injury (SCI).

METHODS

Systematic electronic searches were carried out in the PubMed/Medline, EMBASE, Cochrane Central Register of Controlled Trials, and China National Knowledge Infrastructure databases, along with the reference lists in the include studies. Studies were eligible for inclusion if they adopted a controlled clinical design based on human population, the patients suffered from spinal cord injury, the main outcomes were the disorders of bowel function and the intervention was electrical stimulation. Also, the language was limited to English and Chinese.

RESULTS

Eleven studies were included in this systematic review, comprising transcutaneous electrical stimulation, transrectal bowel stimulation, sacral nerve stimulation, intravesical electrical stimulation, etc. Of the 11 studies, 3 were randomized controlled trials, 8 were controlled before-and-after trials. The quality of the included studies was moderate bias risk. Most studies revealed that the electrical stimulation was beneficial for the patient with NBD after SCI.

CONCLUSIONS

Only 11 small clinical studies with 298 participants have evaluated the efficacy of electrical stimulation for NBD after SCI. Although some studies showed electrical stimulation was benefit for the patient with NBD after SCI, there was currently not enough evidence to support the use of electrical stimulation could improve the clinical symptoms of those patients. Thus, well-designed randomized controlled trials with larger patient population are warranted to establish its benefit in clinical practice in the future.

Survey of anal sphincter dysfunction using anal manometry in patients with fecal incontinence: a possible guide to therapy

BACKGROUND

Despite the surge of new medical and surgical approaches to treat fecal incontinence, the types of sphincter abnormalities in patients with incontinence have not been well characterized. We aimed to categorize anal sphincter dysfunction using anorectal manometry in patients with fecal incontinence as a potential guide for improved treatment.

METHODS

A retrospective review of 162 consecutive patients with fecal incontinence referred for anorectal manometry was performed. Resting anal pressure and maximal squeeze pressure were considered as measures of internal anal sphincter and external anal sphincter function respectively.

RESULTS

Mean age of the patients was 63 years (13-89); females (81.5%) and males (18.5%). 74% of the patients had sphincter dysfunction on anorectal manometry. Internal anal sphincter dysfunction was present in 62% patients vs. external anal sphincter dysfunction present in 44% patients. 80% females had abnormal manometry vs. 44% in males (P<0.0001). Internal anal sphincter dysfunction was present in 68% females vs. 37% in males (P=0.0026).

CONCLUSIONS

Overall, abnormal anorectal manometry studies revealed that internal anal sphincter dysfunction is the most common finding, alone or in combination with external anal sphincter dysfunction. We suggest that anorectal manometry may be important to delineate anal sphincter function prior to using newer therapeutic mechanical devices. Future studies using pharmacological agents to increase internal anal sphincter tone may be of clinical importance. Finally, the classification of fecal incontinence based on the type of sphincter dysfunction may be an improved guide in the selection of newer agents in treating fecal incontinence.

Current management of fecal incontinence: Choosing amongst treatment options to optimize outcomes

The severity of fecal incontinence widely varies and can have dramatic devastating impacts on a person’s life. Fecal incontinence is common, though it is often under-reported by patients. In addition to standard treatment options, new treatments have been developed during the past decade to attempt to effectively treat fecal incontinence with minimal morbidity. Non-operative treatments include dietary modifications, medications, and biofeedback therapy. Currently used surgical treatments include repair (sphincteroplasty), stimulation (sacral nerve stimulation or posterior tibial nerve stimulation), replacement (artificial bowel sphincter or muscle transposition) and diversion (stoma formation). Newer augmentation treatments such as radiofrequency energy delivery and injectable materials, are minimally invasive tools that may be good options before proceeding to surgery in some patients with mild fecal incontinence. In general, more invasive surgical treatments are now reserved for moderate to severe fecal incontinence. Functional and quality of life related outcomes, as well as potential complications of the treatment must be considered and the treatment of fecal incontinence must be individualized to the patient. General indications, techniques, and outcomes profiles for the various treatments of fecal incontinence are discussed in detail. Choosing the most effective treatment for the individual patient is essential to achieve optimal outcomes in the treatment of fecal incontinence.

Anal plugs for the management of fecal incontinence in children and adults: a randomized control trial

GOALS

To evaluate the contribution of the anal plug to the management of fecal incontinence in children and adults.

BACKGROUND

Effective management of fecal incontinence remains problematic. Previous studies of an anal plug have yielded conflicting results.

STUDY

A randomized controlled trial was conducted. The intervention was the Conveen anal plug (Coloplast Limited) used for 12 months. Outcomes measures included: generic measures of child health [Functional Status II-R, Child Health Questionnaire (CHQ-PF50) and Dartmouth Primary Care Cooperative Information Project Charts]; generic measures of adult health for patients and carers (the SF-36, and Patient Generated and Carer Generated indices); condition-specific measures for adults and children; qualitative interviews, bowel charts, and diaries. The main outcome measure was a condition-specific score on a 0 to 100 scale, where 0 was the most severe and 100 was the least severe incontinence.

RESULTS

Thirty-one intervention and 17 control patients were recruited. Fecal incontinence was due to 1 of 3 reasons: congenital, acquired, and neurogenic. At baseline, patients managed their condition preemptively or protectively. Intervention patients used the plug as a complete management substitute or as an adjunct to existing management. The majority of intervention respondents retained the plug most of the time. There was greater improvement from baseline in mean condition-specific score in intervention group compared with control group but this difference was not statistically significant (t test P=0.053). Complete data analysis using analysis of covariance showed the mean difference between the treatment groups in condition-specific score of 9.9 (95% confidence interval-1.4, 21.1). Intention to treat analyses using imputation showed similar results. There was generally greater improvement in intervention groups subjects using other measures for children, adults, and carers.

CONCLUSIONS

The anal plug is of benefit to the majority of patients. It does not suit all eligible patients with in situ plug retention being a problem for some.