Initial experience with SphinKeeper™ intersphincteric implants for faecal incontinence in the UK: a two-centre retrospective clinical audit

AIM

The SphinKeeper™ artificial bowel sphincter implant is a relatively new surgical technique for the treatment of refractory faecal incontinence. This study presents the first experience in two UK tertiary centres.

METHOD

This is a retrospective audit of prospectively collected clinical data in relation to technique, safety, feasibility and short-term effectiveness from patients undergoing surgery from January 2016 to April 2019. Baseline data, intra-operative and postoperative complications, symptoms [using St Mark's incontinence score (SMIS)] and radiological outcomes were analysed.

RESULTS

Twenty-seven patients [18 women, median age 57 years (range 27-87)] underwent SphinKeeper. In 30% of the patients, the firing device jammed and not all prostheses were delivered. There were no intra-operative complications and all patients were discharged the same or the following day. SMIS significantly improved from baseline [median -6 points (range -12 to +3); P < 0.00016] with 14/27 (51.9%) patients achieving a 50% reduction in the SMIS score. On postoperative imaging, a median of seven prostheses (range 0-10) were identified with a median of five (range 0-10) optimally placed. There was no relationship between number of well-sited prostheses on postoperative imaging and categorical success based on 50% reduction in SMIS (χ² test, P = 0.79).

CONCLUSION

SphinKeeper appears to be a safe procedure for faecal incontinence. Overall, about 50% patients achieved a meaningful improvement in symptoms. However, clinical benefit was unrelated to the rate of misplaced/migrated implants. This has implications for confidence in proof of mechanism and also the need for technical refinement.

Botulinum toxin type A for the treatment of dyssynergic defaecation in adults: a systematic review

AIM

Dyssynergic defaecation (DD) is characterized by inappropriate coordination of the pelvic floor muscles during defaecation, resulting in impaired stool expulsion. The mainstay of treatment is biofeedback and alternative therapies are limited in those who do not respond. This systematic review evaluated botulinum toxin type A injection (BTXA) as a treatment option for dyssynergia.

METHODS

PubMed, Embase and Cochrane Central Register of Controlled Trials were searched for studies evaluating adult patients with DD treated with BTXA injection into the puborectalis and/or external anal sphincter. All study designs, except case reports, were included in the review with no language restriction. Studies limited to patients with specific neurological diagnoses or with a follow-up period under 1 month were excluded. Study selection, assessment and data extraction were performed by two reviewers and results were synthesized narratively.

RESULTS

Eleven studies (three randomized control trials) involving 248 participants were included. All studies used the transanal approach to deliver the injection, most commonly at the 3 and 9 o'clock positions using digital palpation for guidance. The most commonly used patient position was left lateral, and most studies did not use any anaesthesia. The dose of BTXA varied (Botox 12-100 units, Dysport 100-500 units), and outcomes measured were heterogeneous (global rating ± up to five investigations). Symptomatic improvement varied between 29.2% and 100% and adverse effects occurred in 0% to 70%.

CONCLUSION

The evidence to support using BTXA for DD is poor and only covers a transanal approach. Future studies should redress these limitations: heterogeneity of design, dose and outcome measures.

The relationships between the results of contemporary tests of anorectal structure and sensorimotor function and the severity of fecal incontinence

BACKGROUND

Diagnostic investigations for fecal incontinence (FI) assess the structure and sensorimotor function of the anorectum. Investigations include anorectal manometry, anorectal sensory testing, pudendal nerve terminal motor latencies (PNTML), and endoanal sonography. The severity of FI and results of investigations are often discordant and the rate of symptom resolution following treatment remains <40%. High-resolution anorectal manometry (HRAM) and three-dimensional endoanal ultrasound (3D-US) have been introduced during the last decade. This study aims to assess the strength of relationships between contemporary investigation results and FI severity.

METHODS

Adults presenting for investigation of FI were assessed using the St Mark's FI severity score (SMIS), HRAM, anorectal sensory testing, PNTML, and 3D-US.

KEY RESULTS

246 patients were included. There were significant relationships between the SMIS and HRAM (resting pressure r_s = -0.23, 95% CI = (-0.34, -0.11), P < .001; squeeze pressure (r_s  = -0.26, 95% CI = (-0.37, -0.14), P < .001) and 3D-US (anterior EAS length r_s = -0.22, 95% CI = (-0.34, -0.09), P = .001). The relationships between SMIS and HRAM had a greater effect size in those with urge-predominant symptoms (resting pressure: r_s = -0.40, 95% CI = (-0.57, -0.20), P < .001, squeeze pressure: r_s = -0.34, 95% CI = (-0.52, -0.12), P = .003). Overall, the variance in SMIS accounted for by anorectal investigations was 8.6% (R² = 0.098, adjusted R² = 0.086, P < .001).

CONCLUSIONS AND INFERENCES

Anorectal investigations are not strong predictors of FI severity. These findings may reflect the multifactorial, heterogeneous pathophysiology of FI, the limitations of the SMIS and anorectal investigations, and contributing factors extrinsic to the anorectum.

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.

GW190521: A Binary Black Hole Merger with a Total Mass of 150 M_{⊙}

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21}  M_{⊙} and 66_{-18}^{+17}  M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28}  M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4}  Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30}  Gpc^{-3} yr^{-1}.

Association between opioid usage and rectal dysfunction in constipation: A cross-sectional study of 2754 patients

BACKGROUND

Opioid use has reached epidemic proportions. In contrast to the known effect of opioids on gut transit, the effect on rectal sensorimotor function has not been comprehensively investigated.

METHODS

Cross-sectional (hypothesis-generating) study of anorectal physiology studies in 2754 adult patients referred to a tertiary unit (2004-2016) for investigation of functional constipation (defined by "derived" Rome IV core criteria). Statistical associations between opioid usage, symptoms, and anorectal physiological variables were investigated. Opioids were sub-classified as prescriptions for mild-moderate or moderate-severe pain.

KEY RESULTS

A total of 2354 patients (85.5%) were classified as non-opioid users, 162 (5.9%) as opioid users for mild-moderate pain, and 238 (8.6%) for moderate-severe pain. Opioids for moderate-severe pain were associated with increased symptomatic severity (Cleveland Clinic constipation score 18.5 vs 15.1; mean difference 2.9 [95%-CI 2.3-3.6]; P < .001), rectal hyposensitivity (odds ratio 1.74 [95%-CI 1.23-2.46]; P = .002), functional evacuation disorders (odds ratio 1.73 [95%-CI 1.28-2.34]; P < .001), and delayed whole-gut transit (odds ratio 1.68 [95%-CI 1.19-2.37]; P = .003). Differences in anorectal variables between opioid users for mild-moderate pain and non-opioid users were not statistically significant. Hierarchical opioid use (non vs mild-moderate vs moderate-severe) was associated with decreasing proportions of patients with no physiological abnormality on testing (40.2% vs 38.1% vs 29.2%) and increasing proportions with both delayed whole-gut transit and rectal sensorimotor dysfunction (16.6% vs 17.5% vs 28.5%).

CONCLUSIONS AND INFERENCES

Opioid use is over-represented in patients referred for investigation of constipation. Opioids for moderate-severe pain are associated with rectal sensorimotor abnormalities. Further studies are required to determine whether this association indicates causation.

Normative values for gastric motility assessed with the 3D-transit electromagnetic tracking system

BACKGROUND

The Motilis 3D-Transit system allows ambulatory description of transit patterns throughout the gastrointestinal tract and offers an alternative method for studying gastric motility. We aimed to establish normative values for gastric motility assessed with the method.

METHOD

A total of 132 healthy volunteers ingested the 3D-Transit capsule for assessment of gastrointestinal transit times. Recordings from 125 subjects were used for definition of normative values. Forty-six subjects were studied on two consecutive days. Recordings were reanalyzed using newly developed software providing information on gastric emptying (GE) as well as contraction frequency and movement during gastric contractions.

RESULTS

The median GE time was 2.7 hours (range 0.1-21.2). In 89% of subjects, the capsule passed the pylorus within a postingestion period of 6 hours. The median frequency of gastric contractions was 3.1 per minute (range 2.6-3.8). The frequency was higher in women (3.2, range 2.7-3.8) than in men (3.0, range 2.6-3.5) and increased with age (0.004 per year) (P < .05). The median amplitudes were 35° (range 4-85) when based on rotation of the capsule and 11 mm (range 6-31) when based on capsule change in position. The rotation amplitude was higher in women and decreased with increasing BMI (P < .05). The position amplitude was also higher in women and increased with the amount of calories in the test meal, but decreased with increasing BMI and age (P < .05). Day-to-day variation (P > .05) was considerable while inter-rater variability was small.

CONCLUSION AND INFERENCES

We have established normative values for gastric motility assessed with the 3D-Transit system.

Ambulatory assessment of colonic motility using the electromagnetic capsule tracking system: Effect of opioids

BACKGROUND

Opioid treatment often causes debilitating constipation. However, it is not well described how opioids affect colonic motility and whether opioid-induced constipation is due to either a decrease of powerful peristaltic contractions or "uncoordinated" peristalsis. The present study aims to investigate the effect of oxycodone on parameters of colonic motility and to determine whether motility is normalized by the opioid antagonist naloxegol.

METHODS

In two randomized, double-blind crossover trials, oxycodone or placebo was administered to 25 healthy males (Trial A), while another 24 healthy males were administered oxycodone with naloxegol or placebo (Trial B). Colonic motility was assessed by tracking the progression of an electromagnetic capsule throughout the large intestine. Segmental colonic transit times and capsule movements were calculated using displacement distance and velocity.

KEY RESULTS

In Trial A, colonic transit time increased during oxycodone treatment compared with placebo (39 vs 18 hours, P < .01). Displacement during long fast antegrade movements was shorter during oxycodone treatment than with placebo (10 vs 20 cm, P = .03). In Trial B, colonic transit time was faster during oxycodone + naloxegol than during oxycodone + placebo (40 vs 55 hours, P = .049), mainly caused by an increase of the percentwise fraction of distance covered by fast movements in the left colon (P = .001).

CONCLUSION & INFERENCES

Oxycodone treatment impaired colonic motility, manifested as increased transit time, specifically decreased long fast antegrade movements, and addition of naloxegol improved motility dynamics. In humans, the increased transit time during opioid treatment is caused by a decrease in long fast movements rather than uncoordinated peristalsis.

European society of neurogastroenterology and motility guidelines on functional constipation in adults

INTRODUCTION

Chronic constipation is a common disorder with a reported prevalence ranging from 3% to 27% in the general population. Several management strategies, including diagnostic tests, empiric treatments, and specific treatments, have been developed. Our aim was to develop European guidelines for the clinical management of constipation.

DESIGN

After a thorough review of the literature by experts in relevant fields, including gastroenterologists, surgeons, general practitioners, radiologists, and experts in gastrointestinal motility testing from various European countries, a Delphi consensus process was used to produce statements and practical algorithms for the management of chronic constipation.

KEY RESULTS

Seventy-three final statements were agreed upon after the Delphi process. The level of evidence for most statements was low or very low. A high level of evidence was agreed only for anorectal manometry as a comprehensive evaluation of anorectal function and for treatment with osmotic laxatives, especially polyethylene glycol, the prokinetic drug prucalopride, secretagogues, such as linaclotide and lubiprostone and PAMORAs for the treatment of opioid-induced constipation. However, the level of agreement between the authors was good for most statements (80% or more of the authors). The greatest disagreement was related to the surgical management of constipation.

CONCLUSIONS AND INFERENCES

European guidelines on chronic constipation, with recommendations and algorithms, were developed by experts. Despite the high level of agreement between the different experts, the level of scientific evidence for most recommendations was low, highlighting the need for future research to increase the evidence and improve treatment outcomes in these patients.

Normative values for region-specific colonic and gastrointestinal transit times in 111 healthy volunteers using the 3D-Transit electromagnet tracking system: Influence of age, gender, and body mass index

BACKGROUND

The 3D-Transit electromagnet tracking system (Motilis Medica, SA, Lausanne, Switzerland) is an emerging tool for the ambulatory assessment of gastrointestinal (GI) transit and motility. Using this tool, we aimed to derive normative values for region-specific colonic and GI transit times and to assess the influence of age, gender, and body mass index (BMI).

METHODS

Regional and total colonic transit times (CTT), gastric emptying (GET), small intestinal (SITT), and whole gut (WGTT) transit times were extracted from 111 healthy volunteers from the United Kingdom and Denmark (58 female; median age: 40 years [range: 21-88]). The effects of age, gender, and BMI were assessed using standard statistical methods.

KEY RESULTS

The ascending, transverse, descending, and rectosigmoid colon transit times accounted for 32%, 34%, 17%, and 17% of total CTT in females, and 33%, 25%, 14%, and 28% of total CTT in males. CTT and WGTT were seen to cluster at intervals separated by approximately 24 hours, providing further evidence of the non-continuous nature of these measurements. Increasing age was associated with longer CTT (P = .021), WGTT (P < .001) ascending (P = .004), transverse (P < .001), and total right (P < .001) colon transit times, but shorter rectosigmoid (P = .004) transit time. Female gender was significantly associated with longer transverse (P = .049) and descending (P < .001) colon transit times, but shorter rectosigmoid (P < .001) transit time. Increasing BMI was significantly associated with shorter WGTT (P = .012).

CONCLUSIONS AND INFERENCES

For the first time, normative reference values for region-specific colonic transit have been presented. Age, gender, and BMI were seen to have an effect on transit times.

The international anorectal physiology working group (IAPWG) recommendations: Standardized testing protocol and the London classification for disorders of anorectal function

BACKGROUND

This manuscript summarizes consensus reached by the International Anorectal Physiology Working Group (IAPWG) for the performance, terminology used, and interpretation of anorectal function testing including anorectal manometry (focused on high-resolution manometry), the rectal sensory test, and the balloon expulsion test. Based on these measurements, a classification system for disorders of anorectal function is proposed.

METHODS

Twenty-nine working group members (clinicians/academics in the field of gastroenterology, coloproctology, and gastrointestinal physiology) were invited to six face-to-face and three remote meetings to derive consensus between 2014 and 2018.

KEY RECOMMENDATIONS

The IAPWG protocol for the performance of anorectal function testing recommends a standardized sequence of maneuvers to test rectoanal reflexes, anal tone and contractility, rectoanal coordination, and rectal sensation. Major findings not seen in healthy controls defined by the classification are as follows: rectoanal areflexia, anal hypotension and hypocontractility, rectal hyposensitivity, and hypersensitivity. Minor and inconclusive findings that can be present in health and require additional information prior to diagnosis include anal hypertension and dyssynergia.

CONCLUSIONS AND INFERENCES

This framework introduces the IAPWG protocol and the London classification for disorders of anorectal function based on objective physiological measurement. The use of a common language to describe results of diagnostic tests, standard operating procedures, and a consensus classification system is designed to bring much-needed standardization to these techniques.

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2  M_{⊙}-1.0  M_{⊙}. We use the null result to constrain the binary merger rate of (0.2  M_{⊙}, 0.2  M_{⊙}) binaries to be less than 3.7×10^{5}  Gpc^{-3} yr^{-1} and the binary merger rate of (1.0  M_{⊙}, 1.0  M_{⊙}) binaries to be less than 5.2×10^{3}  Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2  M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0  M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

Tests of General Relativity with GW170817

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

Spatio-temporal motility MRI analysis of the stomach and colon

BACKGROUND

MRI is increasingly used to objectively assess gastrointestinal motility. However, motility metrics often do not offer insights into the nature of contractile action. This study introduces a systematic method of making spatio-temporal measurements of contractions, based on changes in bowel lumen diameter.

METHODS

Two heterogeneous cohorts of subjects were selected displaying gastric (n = 15) and colonic motility (n = 20) on which to test the spatio-temporal motility MRI (STMM) technique. STMM involved delineating the bowel lumen along with inner and outer bowel wall along a section of the gastrointestinal tract. A series of diameter measurements were made automatically across the central axis of the lumen. Measurements were automatically propagated through the time series using a previously validated algorithm. Contractions were quantitatively summarized with two methods measuring (a) normalized contraction plot (NCP) and (b) combined velocity distance (CVD) both of which can be visualized as spatio-temporal motility maps. Both metrics were correlated against subjective visual scoring systems.

KEY RESULTS

Good correlation was seen between reader scores and both motility metrics (NCP, R = 0.85, P < 0.001, CVD, R = 0.93, R < 0.001) in the gastric data. Good correlation was also seen between the reader scores and the two metrics in the colonic data (NCP, R = 0.82, P < 0.001, CVD, R = 0.78, R < 0.001).

CONCLUSIONS AND INFERENCES

Spatio-temporal motility MRI analysis of the stomach and colon correlates well with reader scores in a range of datasets and provides both a quantitative and qualitative means of assessing contractile activity in the gastrointestinal tract.

Functional anal canal length measurement using high-resolution anorectal manometry to investigate anal sphincter dysfunction in patients with fecal incontinence or constipation

BACKGROUND

Using high-resolution anorectal manometry, we aimed to evaluate the: (a) optimal threshold to measure functional anal canal length (FACL) with intra- and inter-observer variability; (b) relationship between abnormal FACL and other phenotypic findings; and (c) utility of FACL measurement to discriminate between healthy volunteers (HV) and patients with fecal incontinence (FI) or chronic constipation (CC).

METHODS

Consecutive patients referred for investigation of FI or CC in isolation were included. FACL was calculated at 5, 10, 20, 30, and 50 mm Hg above rectal pressure. 5th-95th percentile in HV defined limits of normality.

KEY RESULTS

FACL was analyzed in 192 patients with FI (154 females), 204 patients with CC (175 females), and 134 HV (101 females). The optimal threshold for measurement of FACL was 20 mm Hg. Using this threshold, observer reproducibility was very high (ICC 0.99, P < 0.0001). FACL was shorter in females with FI and longer in females with CC compared to HV (2.3 vs 2.9 cm; and 3.4 cm vs 2.9 cm; both P < 0.0001). Twenty percent of females and 13% males with FI had a short FACL, associated with older age, anal hypotonia or hypocontractility, and a atrophic internal anal sphincter. However, abnormal FACL in isolation was only found in 1/190 FI (0.5%) and 2/201 CC (1%) patients; all other patients had other abnormal manometric findings.

CONCLUSIONS AND INFERENCES

Considering overlap with other routinely evaluated manometric parameters, FACL measurement does not provide additional information in the diagnostic assessment of FI or CC.

Constraining the p-Mode-g-Mode Tidal Instability with GW170817

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4  M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70  Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51}  erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

Ambulatory assessment of colonic motility using the electromagnetic capsule tracking system

BACKGROUND

The Motilis 3D-Transit system tracks electromagnetic capsules as they traverse the gastrointestinal tract. The method is minimally invasive and ambulatory. Analysis has previously been limited to regional gut transit times, but new methods may allow detailed analysis of colonic motility.

METHODS

Parameters of colonic motility were analyzed from 34 3D-Transit recordings performed in healthy volunteers (median age 28 years; 8 F). Characteristic propulsive velocities and lengths of movement were determined to quantify common movement patterns. Data from seven patients with severe chronic diarrhea were included for comparison.

KEY RESULTS

Lack of capsule motion accounted for 82% (75%-87%) of total colonic transit time. Propulsive velocities were distributed with peaks at 0.5 cm/min (antegrade or retrograde) and 50 cm/min (antegrade). Based on velocity and length of propagation, five motor patterns were identified; (a) long fast antegrade, (b) fast antegrade, (c) slow antegrade, (d) slow retrograde, and (e) fast retrograde movements. Long fast antegrade movements were median 21 cm (10-96 cm). Capsule progression was faster during daytime than at night (5.9 cm/h vs 0.8 cm/h; P < 0.01). Colonic transit was faster in patients with chronic diarrhea than in healthy volunteers (5.4 h vs 18.2 h; P = 0.04), with higher capsule velocity (20.4 cm/h vs 4.4 cm/h; P < 0.01).

CONCLUSIONS AND INFERENCES

The 3D-Transit system now allows detailed description of colonic motility and our results are supported by those previously suggested by manometry. It holds promise for future assessment of movement patterns to characterize different diseases and effects of treatment.

High-resolution Anorectal Manometry Measures Are More Accurate Than Conventional Measures in Detecting Anal Hypocontractility in Women With Fecal Incontinence

BACKGROUND & AIMS

Anorectal manometry is a common test of anal tone and contractility. However, existing measures are often criticized for their poor ability to detect functional differences between individuals with presumably normal sphincter function and individuals with fecal incontinence. We investigated whether new measures, derived from high-resolution anal manometry (HR-ARM), more accurately identify incontinent women with abnormal sphincter function than measures from conventional anal manometry (C-ARM).

METHODS

We performed a prospective HR-ARM study of 85 healthy female volunteers (median age 41 years; range 18-68 years) and 403 women with fecal incontinence (median age 55; range 18-91 years) from June 2013 through December 2015. We compared the diagnostic accuracy of conventional measurements of contractility (C-ARM squeeze increment) and tone (C-ARM resting pressure) (the reference standards), with HR-ARM measures (HR-ARM squeeze increment, HR-ARM contractile integral, HR-ARM resting average, HR-ARM rest integral). We also investigated associations between symptom severity and structural sphincter integrity.

RESULTS

We identified anal hypocontractility in 129 women with fecal incontinence using the C-ARM squeeze increment (32% sensitivity; likelihood ratio, 6.4), in 189 women using the HR-ARM squeeze increment (47% sensitivity; likelihood ratio, 9.4), and in 220 women using the HR-ARM contractile integral (55% sensitivity; likelihood ratio, 11.0). In contrast, HR-ARM measures of anal tone did not particularly outperform conventional measures (31% sensitivity for HR-ARM resting average vs 28% for C-ARM resting pressure). Ninety-eight of the 206 patients with fecal incontinence who were classified as having normal anal function, based on C-ARM measures, were reclassified as having abnormal function based on HR-ARM measures.

CONCLUSION

In a prospective study of healthy women and women with fecal incontinence, we demonstrated that the newly developed HR-ARM contractile integral increased the sensitivity of detection of anal hypocontractility, from 32% to 55%, compared with conventional measurements of squeeze.

Randomised clinical trial: Bifidobacterium lactis NCC2818 probiotic vs placebo, and impact on gut transit time, symptoms, and gut microbiology in chronic constipation

BACKGROUND

Constipation is a prevalent gastrointestinal disorder. Patient dissatisfaction with prescribed medications is common, and there is need for alternative management strategies. Evidence shows that Bifidobacterium species may be beneficial in constipation.

AIM

To investigate changes in physiological and clinical measures of gut function in patients with chronic constipation following the consumption of Bifidobacterium lactis NCC2818, compared to placebo.

METHODS

Participants were randomised to a 4-week supplementation with B. lactis NCC2818 (1.5 x 10¹⁰ CFU/d) or placebo. Gut transit time was measured using a radio-opaque marker, while symptoms and quality of life were assessed using validated questionnaires. Gut microbiota composition was assessed using quantitative polymerase chain reaction. Analysis of covariance was used for normally distributed variables, and Mann-Whitney test for non-normally distributed variables.

RESULTS

Seventy-five participants were randomised. There was no significant difference between the probiotic and placebo groups in gut transit time change from baseline to week 2 (-11.7 hours, SD 33.0 hours vs -12.9 hours, SD 33.6 hours; P = 0.863) or to week 4 (-20.4 hours, SD 32.5 h vs -8.7 hours, SD 33.8 hours; P = 0.103). There were also no improvements in stool output, symptoms, or quality of life. No differences were found in Bifidobacterium concentrations between the probiotic and placebo groups at week 4 (9.5 log₁₀ /g dry faeces, SD 0.3 vs 9.4 log₁₀ /g, SD 1.0; P = 0.509).

CONCLUSIONS

Bifidobacterium lactis NCC2818 was not effective in the management of mild chronic constipation. This study highlights the importance of further studies and their publication to better understand the strain-specific effects of probiotics.

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

Systematic review with meta-analysis: defecography should be a first-line diagnostic modality in patients with refractory constipation

BACKGROUND

Defecography is considered the reference standard for the assessment of pelvic floor anatomy and function in patients with a refractory evacuation disorder. However, the overlap of radiologically significant findings seen in patients with chronic constipation (CC) and healthy volunteers is poorly defined.

AIM

To systematically review rates of structural and functional abnormalities diagnosed by barium defecography and/or magnetic resonance imaging defecography (MRID) in patients with symptoms of CC and in healthy volunteers.

METHODS

Electronic searches of major databases were performed without date restrictions.

RESULTS

From a total of 1760 records identified, 175 full-text articles were assessed for eligibility. 63 studies were included providing data on outcomes of 7519 barium defecographies and 668 MRIDs in patients with CC, and 225 barium defecographies and 50 MRIDs in healthy volunteers. Pathological high-grade (Oxford III and IV) intussuscepta and large (>4 cm) rectoceles were diagnosed in 23.7% (95% CI: 16.8-31.4) and 15.9% (10.4-22.2) of patients, respectively. Enterocele and perineal descent were observed in 16.8% (12.7-21.4) and 44.4% (36.2-52.7) of patients, respectively. Barium defecography detected more intussuscepta than MRID (OR: 1.52 [1.12-2.14]; P = 0.009]). Normative data for both barium defecography and MRID structural and functional parameters were limited, particularly for MRID (only one eligible study).

CONCLUSIONS

Pathological structural abnormalities, as well as functional abnormalities, are common in patients with chronic constipation. Since structural abnormalities cannot be evaluated using nonimaging test modalities (balloon expulsion and anorectal manometry), defecography should be considered the first-line diagnostic test if resources allow.

Regional gastrointestinal pH profile is altered in patients with type 1 diabetes and peripheral neuropathy

BACKGROUND

Gastrointestinal (GI) symptoms, such as nausea and bloating, are common in people with type 1 diabetes (T1DM). Autonomic dysfunction can lead to changes in the GI secreto-motor function which can be associated with GI symptom development. We hypothesized that regional pH profiles in T1DM differs from health and would be associated with objective physiological/clinical markers.

METHODS

Forty-seven T1DM with confirmed diabetic sensory peripheral neuropathy and 41 healthy age-matched subjects underwent standardized wireless motility capsule testing. T1DM completed the gastroparesis cardinal symptom index (GCSI) and the gastrointestinal symptom rating scale. Disease duration, glycemic control, insulin usage, and 24-hour heart rate variability testing were evaluated.

KEY RESULTS

In comparison to healthy subjects, gastric, and large bowel median pH were lower in T1DM (1.8 ± 1.6 vs 2.9 ± 1.5, P = 0.001 and 6.7 ± 0.6 vs 7.0 ± 0.5, P = 0.003, respectively). Additionally, change in pH across the pylorus was lower while change in pH across the ileocecal junction was higher in T1DM (5.2 ± 1.5 vs 5.8 ± 0.5, P = 0.003 and 1.8 ± 0.4 vs 1.3 ± 0.4, P < 0.0001, respectively). No difference was found in small bowel median pH. Gastric median pH was associated with small bowel transit time (r = 0.30, P = 0.049). Change in pH across the pylorus was negatively associated with fasting glycose (r = -0.35, P = 0.027). Small bowel median pH was associated with nausea (r = 0.42, P = 0.005) and small bowel transit time (r = 0.48, P = 0.0007). Large bowel median pH was associated with nausea (r = 0.35, P = 0.018) and the total GCSI score (r = 0.34, P = 0.023).

CONCLUSIONS AND INFERENCES

The GI pH profile in T1DM with DSPN is different from healthy subjects. Changes in pH profile may have important therapeutic implications and influence pharmacotherapeutic bioavailability.

Technical report: Inter- and intra-rater reliability of regional gastrointestinal transit times measured using the 3D-Transit electromagnet tracking system

BACKGROUND

The 3D-Transit electromagnet tracking system is an emerging tool for the ambulatory assessment of gastrointestinal (GI) transit times and motility patterns, based on the anatomical localization of ingestible electromagnetic capsules. Currently, 3D-Transit recordings are manually analyzed to extract GI transit times. As this is a subjective method, there is some inherent variability in the measurements, which may be experience-dependent. We therefore assessed inter- and intra-rater reliability of GI transit times from 3D-Transit recordings.

METHODS

Thirty-six 3D-Transit recordings (17 female; median age: 34 years [range: 21-80]) were analyzed twice by 3 raters with varying experience. Each rater manually identified the timestamps when a capsule progressed from antrum to duodenum, and from ileum to right colon. These timestamps, along with the ingestion and expulsion times, were used to determine whole gut (WGTT), gastric emptying (GET), small intestinal (SITT) and colonic (CTT) transit times. Reliability was determined using interclass correlation coefficients (ICCs).

KEY RESULTS

For capsule progression timestamps, the most and mid-experienced raters had fair to good inter- and excellent intra-rater reliability (ICC_min-max  = 0.61-1.00), whereas the inexperienced rater had poor to fair inter- and poor intra-rater reliability (ICC_min-max  = 0.28-0.55). GET and SITT reliability between the most and mid-experienced raters was fair (ICC_min-max  = 0.61-0.73), while reliability between these raters and the inexperienced rater was poor to fair (ICC_min-max  = 0.28-0.55). CTT reliability was excellent between and within all raters (ICC_min-max  = 0.92-0.99).

CONCLUSIONS & INFERENCES

Inexperienced raters provide the least reliable measurements from 3D-Transit recordings, which confirms requirement for adequate training. Automation may improve the reliability of measurements.