Manometry of the Human Ileum and Ileocaecal Junction in Health, Disease and Surgery: A Systematic Review

Risk Assessment of Stoma Outlet Obstruction Development when a Temporary Ileostomy is Created during Rectal Cancer Surgery

Objectives

In surgery for lower rectal cancer, temporary ileostomy can be created to avoid complications, such as anastomotic leakage. However, various complications may occur with the stoma, including stoma outlet obstruction (SOO). The occurrence of SOO can prolong the length of hospital stay and delay the introduction of adjuvant chemotherapy, which can negatively affect the prognosis. We retrospectively reviewed cases of temporary ileostomy at our hospital and evaluated the risk factors for SOO.

Methods

We extracted data pertaining to patients with temporary ileostomy created during surgery for rectal cancer from 2013 to 2023, and compared clinicopathologic factors or short-term outcomes, with or without SOO complications. We scored the independent factors obtained and created predictive scoring model for SOO.

Results

Total of 107 patients were included. SOO was observed in 21 patients (19.6%), all of whom were male. SOO was most frequently diagnosed on sixth postoperative day. In most cases, feeding resumed 4 days after the diagnosis of SOO. Age (≥67 years; p = 0.002), rectus abdominis muscle thickness (≥13.5 mm; p < 0.001) and the amount of stoma output greater than 1,500 ml/day within 3 days of surgery (p < 0.001) were independent risk factors for SOO. The preoperative and early postoperative predictive scoring model, created by adding one point to each risk factor, predicted SOO with sensitivity of 76.2%, specificity of 89.5%.

Conclusions

Age, gender, rectus abdominis muscle thickness, and high early postoperative output are risk factors for SOO. A scoring model may be useful for predicting SOO.

Ultrasonographic assessment of the normal ileocecocolic junction in dogs

The ultrasonographic appearance of the ileocecocolic junction (ICCJ), comprising the ileocolic junction (ICJ) and the cecocolic junction (CCJ), has not been established in dogs. The purpose of this prospective study was (1) to evaluate the feasibility and technique of systematic ultrasonographic evaluation of the ICJ and CCJ and (2) to describe its ultrasonographic features. Abdominal ultrasound was performed in 102 fasted dogs, free of digestive signs. The time required to identify the ICJ using a standardized method was recorded for each operator and compared among four experienced ultrasonographers (ECVDI certified and associated member ECVDI) and two previously trained ECVDI residents to evaluate the feasibility of the technique. Measurements were obtained for the ICJ wall thickness. Evaluation of the contents and peristalsis of the ICJ was recorded for descriptive purposes. The easiest way to identify the ICJ was to follow the colon proximally from the urinary bladder to the ICJ. The probe was then rotated anticlockwise and shifted slightly laterally while increasing the pressure to obtain a longitudinal section of the ICJ. The ICJ was identified in less than 2 min in 98% of cases by experienced ultrasonographers and in 86% of cases by ECVDI residents. The canine ICJ appears as a short invagination of the ileum into the colon, whereas the CCJ appears as a small opening of the colon within the cecum. This study suggests that it is possible to nearly systematically identify the ICCJ with ultrasound in dogs using the described method and provides reference values for its ultrasonographic measurements.

A longitudinal study assessing the impact of elexacaftor/tezacaftor/ivacaftor on gut transit and function in people with cystic fibrosis using magnetic resonance imaging (MRI)

BACKGROUND

Gastrointestinal (GI) symptoms in cystic fibrosis (CF) are common and disruptive. The effect of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on the GI tract is not fully understood. The aim was to use magnetic resonance imaging (MRI) to determine if elexacaftor/tezacaftor/ivacaftor (ETI) changed GI function and transit.

METHODS

This was an 18 month prospective, longitudinal, observational study. We enrolled 24 people with CF aged 12 years or older to undergo MRI scans before starting ETI and 3, 6, and 18 months after starting ETI. The primary outcome measure was change in oro-caecal transit time (OCTT) at 6 and 18 months. Secondary outcome measures included change in small bowel water content (SBWC), change in the reduction in small bowel water content following a meal (DeltaSBWC) and change in total colonic volume (TCV).

RESULTS

A total of 21 participants completed MRI scans at 6 months and 11 completed at 18 months. After 18 months of ETI, median OCTT significantly reduced, from >360 min [IQR 240->360] to 240 min [IQR 180-300] (p = 0.02, Wilcoxon signed-rank). Both SBWC and DeltaSBWC increased after starting ETI. TCV reduced significantly after 18 months (p = 0.005, Friedman).

CONCLUSIONS

Our findings suggest an improvement in small bowel transit, small bowel response to food and a reduction in colonic volume after starting ETI. These effects may relate to CFTR activation in the small bowel. To our knowledge this is the first study to show a physiological change in GI transit and function in response to CFTR modulator use through imaging studies.

Diet shapes the metabolite profile in the intact human ileum, which affects PYY release

The human ileum contains a high density of enteroendocrine L-cells, which release the appetite-suppressing hormones glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY) in response to food intake. Recent evidence highlighted the potential role of food structures in PYY release, but the link between food structures, ileal metabolites, and appetite hormone release remains unclear owing to limited access to intact human ileum. In a randomized crossover trial (ISRCTN11327221; isrctn.com), we investigated the role of human ileum in GLP-1 and PYY release by giving healthy volunteers diets differing in fiber and food structure: high-fiber (intact or disrupted food structures) or low-fiber disrupted food structures. We used nasoenteric tubes to sample chyme from the intact distal ileum lumina of humans in the fasted state and every 60 min for 480 min postprandially. We demonstrate the highly dynamic, wide-ranging molecular environment of the ileum over time, with a substantial decrease in ileum bacterial numbers and bacterial metabolites after food intake. We also show that high-fiber diets, independent of food structure, increased PYY release compared with a low-fiber diet during 0 to 240 min postprandially. High-fiber diets also increased ileal stachyose, and a disrupted high-fiber diet increased certain ileal amino acids. Treatment of human ileal organoids with ileal fluids or an amino acid and stachyose mixture stimulated PYY expression in a similar profile to blood PYY concentrations, confirming the role of ileal metabolites in PYY release. Our study demonstrates the diet-induced changes over time in the metabolite environment of intact human ileum, which play a role in PYY release.

Contractility patterns and gastrointestinal movements monitored by a combined magnetic tracking and motility testing unit

BACKGROUND

Ingestible wireless capsules, including the 3D-transit magnetic capsule and the wireless motility capsule (WMC), describe gastrointestinal (GI) motility from changes in position or pressure. This study aimed to combine information on contractile events in terms of position (assessed with the 3D-transit) and change in pressure (assessed with the WMC) throughout the entire GI tract.

METHODS

The 3D-transit capsule and WMC were combined into a single-wireless unit system. Three-dimensional space-time coordinates, pressure, and pH data from a pilot case were analyzed as the combined unit passed the GI tract. Two single and three continuous contraction patterns were defined according to pressure changes and quantified through the GI tract.

KEY RESULTS

The combined unit was well tolerated and provided information on contractions throughout the gut. Single contraction patterns with no significant progressive movement of the unit were most prevalent in the stomach and the rectosigmoid colon. During the continuous contraction patterns, the unit moved in an antegrade or retrograde direction. Longer distance and higher velocity were seen during antegrade than during retrograde movements. The motility indices (as measured with WMC) in combined ascending, transverse and descending colon showed a positive linear association (r = 0.7) to the capsule movements (as measured with 3D-transit).

CONCLUSIONS & INFERENCES

The combined system provides synchronous information about movements and gut contractions. These measurements can be used to extract more information from existing recordings and may enhance our understanding of GI motility in health and disease.

Small bowel water content assessed by MRI in health and disease: a collation of single-centre studies

BACKGROUND

New developments in MRI have allowed the non-invasive, accurate measurement of the small bowel water content (SBWC).

AIMS

To collate studies measuring SBWC following ingestion of a range of foods in both health and disease to provide data for adequately powering future studies in this area.

METHODS

This collation brings together 29 studies including 954 participants (530 healthy, 54 diverticulosis, 255 IBS, 53 functional constipation, 12 cystic fibrosis, 15 Crohn's disease, 20 coeliac disease, 15 scleroderma) which have been carried out in a single centre using comparable study designs.

RESULTS

Fasting SBWC (mean 82 [SD 65] mL) shows high variability with a small decline with advancing age (healthy volunteers only; individual patient data). Fasting values are increased in untreated coeliac disease (202 [290] mL, P = 0.004). Post-prandial SBWC shows less intra-individual variability than fasting values in healthy volunteers. SBWC is increased by eating, most markedly by high fat meals but also by fibre, both viscous and particulate. Indigestible residue accumulates in late post-prandial period but empties soon after ingestion of a high calorie meal which produces a significant drop (by 50 [52] mL) in healthy volunteers. The associated fall in SBWC is abnormal in people with cystic fibrosis (SBWC reduced by 10 [121] mL, P = 0.002) and in people with irritable bowel syndrome with diarrhoea (SBWC reduced by 17 [43] mL, P = 0.007).

CONCLUSIONS

SBWC as assessed by MRI is a valuable biomarker indicating the balance of secretion and absorption in health and disease and the impact of treatments.

In vitro models to evaluate ingestible devices: Present status and current trends

Orally ingestible medical devices offer significant opportunity in the diagnosis and treatment of gastrointestinal conditions. Their development necessitates the use of models that simulate the gastrointestinal environment on both a macro and micro scale. An evolution in scientific technology has enabled a wide range of in vitro, ex vivo and in vivo models to be developed that replicate the gastrointestinal tract. This review describes the landscape of the existing range of in vitro tools that are available to characterize ingestible devices. Models are presented with details on their benefits and limitations with regards to the evaluation of ingestible devices and examples of their use in the evaluation of such devices is presented where available. The multitude of models available provides a suite of tools that can be used in the evaluation of ingestible devices that should be selected on the functionality of the device and the mechanism of its function.