Patterns of impaired internal anal sphincter activity in patients with anal fissure

Characterization of Anal Slow Waves and Ultraslow Waves in Patients With Constipation and Healthy Subjects

BACKGROUND

Anal slow waves (SW) and ultraslow waves (USW) have been documented previously, yet their significance remains uncertain. Our aims were to characterize the prevalence and features of SW and USW in healthy subjects and patients with constipation and to correlate them with clinical features and anorectal physiological testing.

METHODS

Forty-three healthy female subjects and 83 female tertiary referral patients with constipation were included. High-resolution water-perfused manometry was performed. Retrospective blinded descriptive and quantitative analyses of manometric tracings were completed with a focus on SW and USW.

KEY RESULTS

SW were present in 58% of healthy subjects and 62% of constipated patients (p = 0.72) yet USW were seen almost exclusively in constipated patients (27% vs. 2% health; p < 0.0001). Frequencies and mean amplitudes of SW and USW were similar in both groups. Anal resting and squeeze pressures were higher in patients with SW compared to those without (p < 0.001, p = 0.004, respectively). Patients with USW had higher anal resting pressure and shorter duration of sustained squeeze compared to those without (p < 0.001 for both). There was a trend for less obstetric injury in constipated patients with USW compared to those without (23% vs. 48%; p = 0.05).

CONCLUSIONS AND INTERFERENCES

While SW were common in both constipated and healthy subjects, USW were almost exclusively observed in constipated patients. Some correlations were observed with other anorectal physiology parameters such as high resting anal pressure with both SW and USW. Formal definitions for SW and USW are proposed. Further research into the clinical significance of these waves is warranted.

Review of the indications, methods, and clinical utility of anorectal manometry and the rectal balloon expulsion test

BACKGROUND

Anorectal manometry (ARM) comprehensively assesses anorectal sensorimotor functions.

PURPOSE

This review examines the indications, techniques, interpretation, strengths, and weaknesses of high-resolution ARM (HR-ARM), 3-dimensional high-resolution anorectal manometry (3D-HR-ARM), and portable ARM, and other assessments (i.e., rectal sensation and rectal balloon expulsion test) that are performed alongside manometry. It is based on a literature search of articles related to ARM in adults. HR-ARM and 3D-HR-ARM are useful for diagnosing defecatory disorders (DD), to identify anorectal sensorimotor dysfunction and guide management in patients with fecal incontinence (FI), constipation, megacolon, and megarectum; and to screen for anorectal structural (e.g., rectal intussusception) abnormalities. The rectal balloon expulsion test is a useful, low-cost, radiation-free, outpatient assessment tool for impaired evacuation that is performed and interpreted in conjunction with ARM. The anorectal function tests should be interpreted with reference to age- and sex-matched normal values, clinical features, and results of other tests. A larger database of technique-specific normal values and newer paradigms of analyzing anorectal pressure profiles will increase the precision and diagnostic utility of HR-ARM for identifying abnormal mechanisms of defecation and continence.

MEBO versus topical Diltiazem versus a combination of both ointments in the treatment of acute anal fissure: a randomized clinical trial protocol

Background

Anal fissure is a common complication of the anorectal region and one of the most reported causes of anal pain. Acute anal fissure can be cured by surgery or medical treatment. There is an increase in the use of topical therapy for the treatment of anal fissures. A common topical drug used is Diltiazem (DTZ), a calcium-channel blocker, which relaxes the anal sphincter and thus promotes healing of the anal fissure. Moist exposed burn ointment (MEBO) is an ointment that is effective for the treatment of burns and wound healing and is becoming popular in the treatment of anal fissures.

Methods

This is a 1:1:1 randomized, controlled, parallel design, with endpoint measures of change in pain score, wound healing, defecation strain score and patient’s global impression of improvement. The study will be conducted at AUBMC over a 10-week period. Patients will be randomized to three treatment arms: MEBO, Diltiazem, and a combination of MEBO and Diltiazem ointments.

Discussion

The results of this study will allow physicians to assess the efficacy and safety of MEBO in the treatment of acute anal fissure, and also in comparison to Diltiazem. This trial will generate evidence-based conclusions regarding the use of a herbal/natural-based product (MEBO ointment) for the treatment of anal fissures.

Trial registration

ClinicalTrials.gov Identifier NCT04153032. Clinical Trial Registration Date: 06-NOVEMBER-2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03227-z.

The London Classification: Improving Characterization and Classification of Anorectal Function with Anorectal Manometry

PURPOSE OF REVIEW

Objective measurement of anorectal sensorimotor function is a requisite component in the clinical evaluation of patients with intractable symptoms of anorectal dysfunction. Regrettably, the utility of the most established and widely employed investigations for such measurement (anorectal manometry (ARM), rectal sensory testing and the balloon expulsion test) has been limited by wide variations in clinical practice.

RECENT FINDINGS

This article summarizes the recently published International Anorectal Physiology Working Group (IAPWG) consensus and London Classification of anorectal disorders, together with relevant allied literature, to provide guidance on the indications for, equipment, protocol, measurement definitions and results interpretation for ARM, rectal sensory testing and the balloon expulsion test. The London Classification is a standardized method and nomenclature for description of alterations in anorectal motor and sensory function using office-based investigations, adoption of which should bring much needed harmonization of practice.

Rhythmic calcium transients in smooth muscle cells of the mouse internal anal sphincter

BACKGROUND

The internal anal sphincter (IAS) exhibits slow waves (SWs) and tone that are dependent upon L-type Ca²⁺ channels (Cav_L ) suggesting that phasic events (ie, SWs) play a fundamental role in tone generation. The present study further examined phasic activity in the IAS by measuring the spatiotemporal properties of Ca²⁺ transients (CTs) in IAS smooth muscle cells (SMCs).

METHODS

Ca²⁺ transients were recorded with spinning disk confocal microscopy from the IAS of SM-GCaMP mice. Muscles were pinned submucosal surface up at two different lengths. Drugs were applied by inclusion in the superfusate.

KEY RESULTS

Ca²⁺ transients displayed ongoing rhythmic firings at both lengths and were abolished by nifedipine and the K_ATP channel activator pinacidil indicating their dependence upon Cav_L . Like SWs, CTs were greatest in frequency (average 70.6 cpm) and amplitude at the distal extremity and conducted proximally. Removal of the distal IAS reduced but did not abolish CTs. The time constant for clearing cytoplasmic Ca²⁺ averaged 0.46 seconds and basal Ca²⁺ levels were significantly elevated.

CONCLUSIONS & INFERENCES

The similarities in spatiotemporal and pharmacological properties of CTs and SWs suggest that SW gives rise to CTs while muscle stretch is not required. Elevated relative basal Ca²⁺ in the IAS is likely due to the inability of cells to clear or sequester Ca²⁺ between rapid frequency voltage-dependent Ca²⁺ entry events, that is, conditions that will lead to tone development. The conduction of CTs from distal to proximal IAS will lead to orally directed contractions and likely contribute to the maintenance of fecal continence.

High-resolution and high-definition anorectal manometry: rediscovering anorectal function

Anorectal motor and functional disorders are common among the general population. Anorectal manometry allows the study of anorectal motor activity both at rest and mimicking different physiological situations. High-resolution anorectal manometry (HR-ARM) and high-definition anorectal manometry (HD-ARM) are increasingly used in clinical practice. In comparison with the conventional technique, HR-ARM and HD-ARM catheters provide a higher number of recording points because of their many, closely packed circumferential sensors. This allows time-space visualization (topographic or 2-3-plane mode) as spatially continuous measurements are obtained by interpolation between near sensors. HR-ARM and HD-ARM allow a more standardized, reproducible technique, and a better assessment and understanding of the functional anatomy of the sphincter complex. Newer specific parameters are now being developed for use with these systems. They are being currently assessed by multiple research teams, and many of them remain unavailable for clinical practice as of today. However, they provide highly relevant information, which is now prompting a redefinition of anorectal anatomy and physiology. The goal of the present review was to describe the currently available HR-ARM and HD-ARM techniques, to discuss the normal values so far reported, and to analyze the newer parameters that may be assessed with these techniques, and which will likely be highly useful for clinical practice in the upcoming future.

Surface Electromyography Reliably Records Electrophysiologically Evoked Internal Anal Sphincter Activity: A More Minimally Invasive Approach for Monitoring Extrinsic Innervation

BACKGROUND

Even in the case of minimally invasive pelvic surgery, sparing of the autonomic nerve supply is a prerequisite for maintaining anal sphincter function. Internal anal sphincter (IAS) innervation could be electrophysiologically identified based on processed electromyographic (EMG) recordings with conventional bipolar needle electrodes (NE). This experimental study aimed for the development of a minimally invasive approach via intra-anal surface EMG for recordings of evoked IAS activity.

METHODS

Six male pigs underwent nerve-sparing low anterior rectal resection. Electric autonomic nerve stimulations were performed under online-processed EMG of the IAS. EMG recordings were simultaneously carried out with conventional bipolar NE as the reference method and newly developed intra-anal surface electrodes (SE) in different designs.

RESULTS

In all experiments, the IAS activity could be continuously visualized via EMG recordings based on NE and SE. The median number of bipolar electric stimulations per animal was 27 (range 5-52). The neurostimulations resulted in significant EMG amplitude increases for both recording types [NE: median 3.0 µV (interquartile range, IQR 2.8-3.5) before stimulation vs. 7.1 µV (IQR 3.9-13.8) during stimulation, p < 0.001; SE: median 3.6 µV (IQR 3.1-4.3) before stimulation vs. 6.8 µV (IQR 4.8-10.3) during stimulation, p < 0.001].

CONCLUSIONS

Intra-anal SE enabled reliable EMG of electrophysiologically evoked IAS activity similar to the conventional recording via NE. The transfer of the method to access platforms for transanal total mesorectal excision or robotics may offer a practical more minimally invasive approach for monitoring extrinsic innervation.

Quality of Life Differences in Female and Male Patients with Fecal Incontinence

Background/Aims

To explore and compare quality of life (QoL) differences in female and male patients with fecal incontinence.

Methods

Ninety-one patients with fecal incontinence (60 women, mean (SD) age 64.13 (9.72) years; 31 men, mean (SD) age 63.61 (13.33) years) were assessed for pathophysiology (anorectal manometry and ultrasound), clinical severity (Wexner and Vaizey scales), QoL (Fecal Incontinence Quality of Life Score [FIQL]) and health status (EQ-5D).

Results

External and internal anal sphincter impairment rates were 96.5% and 70.2%, respectively, in women, compared to 30% and 43.3% respectively in men (P < 0.05). Clinical severity was similar in both sexes, with mean (SD) Wexner scores of 10.95 (4.35) for women and 9.81 (4.30) for men, and mean (SD) Vaizey scores of 13.27 (4.66) for women and 11.90 (5.22) for men. Scores for women were significantly lower for all FIQL depression and coping subscales (P < 0.001) and the EQ-5D depression subscale (P < 0.01). EQ-5D index was 0.687 (0.20) for women and 0.835 (0.15) for men (P < 0.001). QoL was negatively affected by female gender (−1.336), anxiety/depression (−1.324) and clinical severity (−0.302), whereas age had a positive impact (0.055 per year) (P < 0.01).

Conclusions

The pathophysiology of fecal incontinence differed between the sexes. For similar severity scores, impact on QoL was higher in women. Gender had the highest impact on QoL compared to other factors. QoL measurements should be part of assessment and treatment protocols.

How to Perform and Interpret a High-resolution Anorectal Manometry Test

High-resolution anorectal manometry (HR-ARM) and high-definition anorectal manometry (HD-ARM) catheters have closely spaced water-perfused or solid state circumferentially-oriented pressure sensors that provide much better spatiotemporal pressurization than non-high resolution catheters. This is a comprehensive review of HR-ARM and HD-ARM anorectal manometry catheter systems, the methods for conducting, analyzing, and interpreting HR-ARM and HD-ARM, and a comparison of HR-ARM with non-high resolution anorectal manometry. Compared to non-high resolution techniques, HR-ARM and HD-ARM studies take less time and are easier to interpret. However, HR-ARM and HD-ARM catheters are more expensive and fragile and have a shorter lifespan. Further studies are needed to refine our understanding of normal values and to rigorously evaluate the incremental clinical utility of HR-ARM or HD-ARM compared to non-high resolution manometry.

The use of colonic and anorectal high-resolution manometry and its place in clinical work and in research

BACKGROUND

In the esophagus, high-resolution manometry (HRM) has become a standard diagnostic tool in the investigation of suspected motility disorders. However, at the opposite end of the digestive tract (i.e., the colon and anorectum), the use of HRM still remains in its infancy, with relatively few published studies in the scientific literature. Further, the clinical utility of those studies that have been performed is largely undetermined.

PURPOSE

This review assesses all of the HRM studies published to date from both the colon and anorectum, explores the catheter types used, and attempts to determine the worth of HRM over traditional 'low-resolution' recordings from the same regions. Ultimately, this review addresses whether HRM currently provides information that will benefit patient diagnosis and treatment.

High-dose circumferential chemodenervation of the internal anal sphincter: A new treatment modality for uncomplicated chronic anal fissure: A retrospective cohort study (with video)

BACKGROUND

Botulinum toxin injection into the internal anal sphincter is gaining popularity as a second line therapy for chronic anal fissures if medical therapy fails. The dosage of botulinum toxin reported ranged from 20 to 50 IU with no more than 3 injection sites and results in a healing rate of 41%-88% at 3 months. We propose a new injection method of high-dose circumferential chemodenervation of 100 IU in treating chronic anal fissure.

METHODS

This was a retrospective review at a single academic center. 75 patients (50 women and 25 men) with uncomplicated chronic anal fissures underwent high-dose circumferential chemodenervation-internal anal sphincter (100 IU). We measured fissure healing, complication, and recurrence rates at 3 and 6 months post injection.

RESULTS

Of the 75 patients, healing rate was 90.7% at 3 months follow up with the first injection and 81.3% with the second injection. The recurrence rates were 20.6% and 12.5% at 6 months after the 1st and 2nd injections respectively. Excluding 5 patients who lost follow up, the total healing rate of the study cohort was 100%. At 2 weeks and 3 months, there were no major complications including hematoma, infection, flatus, fecal, and urinary incontinence.

CONCLUSIONS

High-dose circumferential chemodenervation-internal anal sphincter (100 IU) is a safe and effective method for uncomplicated chronic anal fissure.

High resolution and high definition anorectal manometry and pressure topography: diagnostic advance or a new kid on the block?

The recent development of closely spaced circumferential solid state transducers has paved the way for novel technology that includes high resolution anorectal manometry and topography (HRAM) and 3-D high definition anorectal manometry (HDAM). These techniques are increasingly being used for the assessment of anorectal neuromuscular function. However, whether they constitute a diagnostic advantage or a mere refinement of an old technology is unknown. Unlike the traditional manometry that utilized 3 or 6 unidirectional sensors, the closely spaced circumferential arrangement facilitates superior spatiotemporal mapping of pressures at rest and during various dynamic maneuvers. HDAM can provide knowledge of the three muscles that govern the anal continence namely, the puborectalis, and the internal and external anal sphincters, and can show how they mediate the rectoanal inhibitory reflex and sensorimotor responses and the spatiotemporal orientation of these muscles. Also, anal sphincter defects can be mapped and readily detected using 3-D technology. Similarly, HRAM has facilitated confirmation and development of phenotypes of dyssynergic defecation. Recently, normative data have also been reported with HRAM and HDAM, together with the influence of age, gender, and test instructions. The greater yield of anatomical and functional information may supersede the limitations of costs, fragility, and shorter life-span associated with these new techniques. Thus, HDAM and HRAM are not just new gadgets but constitute a significant and novel diagnostic advance. However, more prospective studies are needed to better define anorectal disorders with these techniques and to confirm their superiority.