The mesentery in Crohn's disease: friend or foe?

Does Kono-S Anastomosis Reduce Recurrence in Crohn's Disease Compared with Conventional Ileocolonic Anastomosis? A Nationwide Propensity Score-matched Study from GETAID Chirurgie Group [KoCoRICCO Study]

BACKGROUND AND AIMS

Postoperative recurrence is a major concern in Crohn's disease. The Kono-S anastomosis has been described to reduce the rate of recurrence. However, the level of evidence for its effectiveness remains low. The KoCoRICCO study aimed to compare outcomes between Kono-S anastomosis and conventional anastomosis in two nationwide, prospective cohorts.

METHODS

Adult patients with Crohn's disease, who underwent ileocolonic resection with Kono-S anastomosis, were prospectively included in seven referral centres between 2020 and 2022. Patients with conventional side-to-side anastomosis were enrolled from a previously published cohort. A propensity score analysis was performed to compare recurrence at first endoscopy in a matched 1:2 ratio population.

RESULTS

A total of 433 patients with ileocolonic anastomosis were enrolled, of whom 155 had a Kono-S anastomosis. Before matching, both groups were unbalanced for preoperative, intraoperative, and postoperative characteristics. After matching patients with available endoscopic follow-up, endoscopic recurrence ≥i2 was found in 47.5% of the Kono-S group and 44.3% of the conventional side-to-side group [p = 0.6745].

CONCLUSIONS

The KoCoRICCO study suggests that Kono-S anastomosis does not reduce the risk of endoscopic recurrence in Crohn's disease compared with conventional side-to-side anastomosis. Further research with a longer follow-up is necessary to determine whether there is a potential benefit on surgical recurrence.

Surgical management of pediatric Crohn's disease

Management of pediatric-onset Crohn's disease uniquely necessitates consideration of growth, pubertal development, psychosocial function and an increased risk for multiple future surgical interventions. Both medical and surgical management are rapidly advancing; therefore, it is increasingly important to define the role of surgery and the breadth of surgical options available for this complex patient population. Particularly, the introduction of biologics has altered the disease course; however, the ultimate need for surgical intervention has remained unchanged. This review defines and evaluates the surgical techniques available for management of the most common phenotypes of pediatric-onset Crohn's disease as well as identifies critical perioperative considerations for optimizing post-surgical outcomes.

First Mexican Consensus on Crohn's disease

INTRODUCTION

Crohn's disease (CD) is a subtype of chronic and incurable inflammatory bowel disease. It can affect the entire gastrointestinal tract and its etiology is unknown.

OBJECTIVE

The aim of this consensus was to establish the most relevant aspects related to definitions, diagnosis, follow-up, medical treatment, and surgical treatment of Crohn's disease in Mexico.

MATERIAL AND METHODS

Mexican specialists in the areas of gastroenterology and inflammatory bowel disease were summoned. The consensus was divided into five modules, with 69 statements. Applying the Delphi panel method, the pre-meeting questions were sent to the participants, to be edited and weighted. At the face-to-face meeting, all the selected articles were shown, underlining their level of clinical evidence; all the statements were discussed, and a final vote was carried out, determining the percentage of agreement for each statement.

RESULTS

The first Mexican consensus on Crohn's disease was produced, in which recommendations for definitions, classifications, diagnostic aspects, follow-up, medical treatment, and surgical treatment were established.

CONCLUSIONS

Updated recommendations are provided that focus on definitions, classifications, diagnostic criteria, follow-up, and guidelines for conventional medical treatment, biologic therapy, and small molecule treatment, as well as surgical management.

Stapled End-To-Side Ileocolic Anastomosis in Crohn's Disease: Old Dog, Reliable Tricks? A Retrospective Two-Center Cohort Study

Objective

Analyze our long-term experience with a less-popularized but stalwart approach, the stapled end-to-side ileocolic anastomosis.

Background

The choice of technical approach to ileocolic anastomosis after ileocecal resection for Crohn's disease affects surgical outcomes and recurrence. Yet, despite heterogeneous data from different anastomotic configurations, there remains no clear guidance as to the optimal technique.

Methods

In a retrospective cohort design, patients undergoing ileocolic anastomosis in the setting of Crohn's disease between 2016 and 2021 at two institutions were identified. Patient characteristics and surgical outcomes in terms of recurrence (surgical, clinical, and endoscopic) were studied.

Results

In total, 211 patients were included. Before surgery, 80% were exposed to at least 1 cycle of systemic steroids and 71% had at least 1 biologic agent; 60% exhibited penetrating disease and 38% developed an intra-abdominal abscess. After surgery, one anastomosis leaked (0.5%). Over 2.4 years of follow-up (IQR = 1.3-3.9), surgical recurrence was 0.9%. Two-year overall recurrence-free and endoscopic recurrence-free survivals were 74% and 85% (95% CI = 68-81 and 80-91), respectively. The adjusted hazard ratio of endoscopic recurrence was 3.0 (95% CI = 1.4-6.2) for males and 5.2 (1.2-22) for patients who received systemic steroids before the surgery.

Conclusion

The stapled end-to-side anastomosis is an efficient, reliable, and reproducible approach to maintain bowel continuity after ileocecal resection with durable outcomes. Our outcomes demonstrate low rates of disease recurrence and stand favorably in comparison to other more technically complex or protracted anastomotic approaches. This anastomosis is an ideal reconstructive approach after ileocecal resection for Crohn's disease.

MSCs mediate long-term efficacy in a Crohn's disease model by sustained anti-inflammatory macrophage programming via efferocytosis

Mesenchymal stem cells (MSCs) are novel therapeutics for the treatment of Crohn's disease. However, their mechanism of action is unclear, especially in disease-relevant chronic models of inflammation. Thus, we used SAMP-1/YitFc (SAMP), a chronic and spontaneous murine model of small intestinal inflammation, to study the therapeutic effects and mechanism of action of human bone marrow-derived MSCs (hMSC). hMSC dose-dependently inhibited naïve T lymphocyte proliferation via prostaglandin E2 (PGE2) secretion and reprogrammed macrophages to an anti-inflammatory phenotype. We found that the hMSCs promoted mucosal healing and immunologic response early after administration in SAMP when live hMSCs are present (until day 9) and resulted in a complete response characterized by mucosal, histological, immunologic, and radiological healing by day 28 when no live hMSCs are present. hMSCs mediate their effect via modulation of T cells and macrophages in the mesentery and mesenteric lymph nodes (mLN). Sc-RNAseq confirmed the anti-inflammatory phenotype of macrophages and identified macrophage efferocytosis of apoptotic hMSCs as a mechanism that explains their long-term efficacy. Taken together, our findings show that hMSCs result in healing and tissue regeneration in a chronic model of small intestinal inflammation and despite being short-lived, exert long-term effects via sustained anti-inflammatory programming of macrophages via efferocytosis.

Extended versus limited mesenteric excision for operative Crohn's disease: 30-Day outcomes from the ACS-NSQIP database

PURPOSE

Recent studies have suggested that extended mesenteric excision (ME) may reduce surgical reintervention in Crohn's Disease (CD), but there remains clinical concerns regarding potential peri-operative morbidity. This retrospective study compares 30-day perioperative morbidity between limited and extended ME in segmental colectomies for CD.

METHODS

Using the American College of Surgeons National Surgical Quality Improvement (ACS-NSQIP) colectomy-specific database, all patients with CD undergoing segmental colectomy for non-malignant indications between 2014-2019 were included. A lymph node harvest of 12 or more nodes was used as a surrogate for extended ME. The primary outcome was NSQIP major morbidity. Secondary outcomes included abdominal complications and perioperative bleeding.

RESULTS

Of 3,709 patients included from the ACS-NSQIP database, 3,087 underwent limited ME and 622 underwent extended ME. On univariate analysis, those with limited mesenteric excision were less likely to be anemic (46.1% vs 55.0%, p < 0.001) and have undergone an open surgery (44.7% vs 34.7%, p < 0.001). On univariate comparison of limited and extended ME, there was no significant difference in major morbidity. On multiple logistic regression, controlling for age, sex, BMI, smoking, preoperative sepsis, preoperative anemia, surgical approach, emergency surgery, stoma creation, bowel preparation, and immunosuppression, the extent of ME was not an independent predictor of NSQIP major morbidity (OR 1.1, 95% CI 0.84-1.44). Likewise, the extent of ME was not associated with an increase in abdominal complications (OR 0.95, 95% CI 0.76-1.19) or post-operative bleeding (OR 1.89, 95% CI 0.75-1.53).

CONCLUSION

Extended ME for CD was not associated with an increase in 30-day perioperative major morbidity.

Use of the Kono-S anastomosis in pediatric Crohn's disease: a single-institution experience

OBJECTIVES

About 24% of children with Crohn's Disease (CD) require surgery. In 2003, Kono et al. described a novel anastomosis reported to decrease the rate of anastomotic CD recurrence. Subsequent studies have reproduced these outcomes, but none has demonstrated its effect in pediatric patients. This study evaluates short-term outcomes of pediatric patients following ileocolic resection and Kono-S anastomosis.

METHODS

A retrospective review of patients < 18 years old who underwent ileocolic resection followed by Kono-S anastomosis compared with those who underwent a stapled anastomosis.

RESULTS

Nine Kono-S patients were matched with nine patients preceding them who received traditional side-to-side and end-to-side anastomoses. All patients underwent minimally invasive surgery. Demographics, pre-operative medication usage, and symptom profiles were not significantly different. Traditional anastomosis (TA) patients had longer lengths of stay (4.6 vs 2.9 days; p = 0.03) but had no statistically significant differences in blood loss, procedure length, and pathologic findings. One Kono-S patient had a superficial surgical site infection, and one TA patient had an anastomotic leak requiring reoperation within 30 days. More TA patients experienced post-operative symptoms at both 30-day and 6-month follow-up (66.7% vs 33.3%; p = 0.16 and 77.8% vs 25%; p = 0.03).

CONCLUSION

The Kono-S anastomosis appears to be safe in pediatric CD when compared to traditional stapled anastomoses.

Results of the Eighth Scientific Workshop of ECCO: Pathophysiology and Risk Factors of Postoperative Crohn's Disease Recurrence after an Ileocolonic Resection

Postoperative recurrence [POR] after an ileocolonic resection with ileocolonic anastomosis is frequently encountered in patients with Crohn's disease. The 8th Scientific Workshop of ECCO reviewed the available evidence on the pathophysiology and risk factors for POR. In this paper, we discuss published data on the role of the microbiome, the mesentery, the immune system and the genetic background. In addition to investigating the causative mechanisms of POR, identification of risk factors is essential to tailor preventive strategies. Potential clinical, surgical and histological risk factors are presented along with their limitations. Emphasis is placed on unanswered research questions, guiding prevention of POR based on individual patient profiles.

Appearance of the Bowel and Mesentery During Surgery Is Not Predictive of Postoperative Recurrence After Ileocecal Resection for Crohn's Disease: A Prospective Monocentric Study

BACKGROUND

Very few risk factors for postoperative recurrence (POR) of Crohn's Disease (CD) after ileocecal resection have been identified. The aim of the present study was to verify the association between an a priori defined list of intraoperative macroscopic findings and POR.

METHODS

This was a prospective observational study including patients undergoing primary ileocecal resection for CD. Four intraoperative factors were independently evaluated by 2 surgeons: length of resected ileum, mesentery thickness, presence of areas of serosal fat infiltration, or abnormal serosal vasodilation on normal bowel proximal to the resected bowel. The primary end point was early endoscopic POR at month 6 and defined as modified Rutgeerts score ≥i2b. Secondary end points were clinical and surgical recurrence.

RESULTS

Between September 2020 and November 2022, 83 consecutive patients were included. Early endoscopic recurrence occurred in 45 of 76 patients (59.2%). Clinical and biochemical recurrence occurred in 17.3% (95% confidence interval, [CI], 10.4%-28.0%) and 14.6% of the patients after 12 months. The risk of developing endoscopic and clinical recurrence was 1.127 (95% CI, 0.448;2.834, P = .799) and 0.896 (95% CI, 0.324-2.478, P = .832) when serosal fat infiltration was observed, and 1.388 (95% CI, 0.554-3.476, P = .484), and 1.153 (95% CI, 0.417;3.187, P = .783) when abnormal serosal vasodilation was observed. Similarly, length of the resected bowel and mesentery thickness showed no association with POR. A subgroup analysis on patients who received no postoperative medical prophylaxis did not identify any risk factor for endoscopic POR.

CONCLUSIONS

The macroscopic appearance of the bowel and associated mesentery during surgery does not seem to be predictive of POR after ileocecal resection for CD.

Mesenchymal stem cells ameliorate inflammation in an experimental model of Crohn's disease via the mesentery

Objective

Mesenchymal stem cells (MSCs) are novel therapeutics for treatment of Crohn's disease. However, their mechanism of action is unclear, especially in disease-relevant chronic models of inflammation. Thus, we used SAMP-1/YitFc, a chronic and spontaneous murine model of small intestinal inflammation, to study the therapeutic effect and mechanism of human bone marrow-derived MSCs (hMSC).

Design

hMSC immunosuppressive potential was evaluated through in vitro mixed lymphocyte reaction, ELISA, macrophage co-culture, and RT-qPCR. Therapeutic efficacy and mechanism in SAMP were studied by stereomicroscopy, histopathology, MRI radiomics, flow cytometry, RT-qPCR, small animal imaging, and single-cell RNA sequencing (Sc-RNAseq).

Results

hMSC dose-dependently inhibited naïve T lymphocyte proliferation in MLR via PGE 2 secretion and reprogrammed macrophages to an anti-inflammatory phenotype. hMSC promoted mucosal healing and immunologic response early after administration in SAMP model of chronic small intestinal inflammation when live hMSCs are present (until day 9) and resulted in complete response characterized by mucosal, histological, immunologic, and radiological healing by day 28 when no live hMSCs are present. hMSC mediate their effect via modulation of T cells and macrophages in the mesentery and mesenteric lymph nodes (mLN). Sc-RNAseq confirmed the anti-inflammatory phenotype of macrophages and identified macrophage efferocytosis of apoptotic hMSCs as a mechanism of action that explains their long-term efficacy.

Conclusion

hMSCs result in healing and tissue regeneration in a chronic model of small intestinal inflammation. Despite being short-lived, exert long-term effects via macrophage reprogramming to an anti-inflammatory phenotype.

Data Transparency Statement

Single-cell RNA transcriptome datasets are deposited in an online open access repository 'Figshare' (DOI: https://doi.org/10.6084/m9.figshare.21453936.v1 ).

Preoperative computed tomography enterography-based radiomics signature: A potential predictor of postoperative anastomotic recurrence in patients with Crohn's disease

BACKGROUND

More than half of patients with Crohn's disease (CD) require at least one surgery for symptom management; however, approximately half of the patients may experience postoperative anastomotic recurrence (PAR).

OBJECTIVES

This study aims to develop and validate a preoperative computed tomography enterography (CTE)-based radiomics signature to predict early PAR in CD.

DESIGN

A total of 186 patients with CD (training cohort, n = 134; test cohort, n = 52) who underwent preoperative CTE and surgery between January 2014 and June 2020 were included in this retrospective multi-centre study.

METHODS

106 radiomic features were initially extracted from intestinal lesions and peri-intestinal mesenteric fat, respectively; significant radiomic features were selected from them and then used to develop intestinal or mesenteric radiomics signatures, using the least absolute shrinkage and selection operator and a Cox regression model. A radiomics-based nomogram incorporating these signatures with clinical-radiological factors was created for comparison with a model based on clinical-radiological features alone.

RESULTS

68 of 134 patients in training cohort and 16 of 52 patients in test cohort suffered from PAR. The intestinal radiomic signature (hazard ratio [HR]: 2.17; 95% confidence interval [CI]: 1.32-3.58; P = 0.002) and mesenteric radiomic signature (HR: 2.19; 95% CI: 1.14-4.19; P = 0.018) were independent risk factors for PAR in the training cohort as per a multivariate analysis. The radiomics-based nomogram (C-index: 0.710; 95% CI: 0.672-0.748) yielded superior predictive performance than the clinical-radiological model (C-index, 0.607; 95% CI: 0.582-0.632) in the test cohort. Decision curve analysis demonstrated that the radiomics-based nomogram outperformed the clinical-radiological model in terms of clinical usefulness.

CONCLUSIONS

Preoperative mesenteric and intestinal CTE radiomics signatures are potential non-invasive predictors of PAR in postoperative patients with CD.

Measurement of the stiffness of the normal terminal ileum mesentery using shear-wave elastography

OBJECTIVE

To investigate the feasibility of using shear-wave elastography (SWE) to measure the stiffness of the normal terminal ileum mesentery, and to establish its normal reference range.

METHODS

Ninety-five normal subjects and 22 patients with mesentery-related disease were included. The average Young's modulus of the normal terminal ileal mesentery was measured by SWE ultrasound. The thickness and the extent to which mesenteric fat extended around the intestinal circumference of the normal terminal ileum were also recorded. The normal reference range was established and the SWE values of normal and diseased subjects were compared.

RESULTS

Transabdominal SWE examination of the terminal ileum mesentery was successfully performed on 91 subjects (95.8 %). The mean extent range, thickness, and SWE value of the normal terminal ileum mesentery were 1/4 (1/5-1/3), 6.8 ± 2.4 mm, and 4.3 ± 2.1 kPa, respectively. These parameters did not differ significantly between genders, and across age and body mass index groups (all P > 0.05). The intra- and inter-operator consistencies were excellent for the replicated SWE measurements (0.801 [95 % confidence interval: 0.560-0.916] and 0.751 (95 % confidence interval: 0.388-0.900], respectively). The mean mesenteric elasticity in diseased subjects was 21.9 ± 10.7 kPa, which was significantly higher than that in normal subjects (P < 0.001). The cut-off value for mesenteric elasticity was 9.3 kPa, with a sensitivity of 90 % and a specificity of 100 % (P < 0.001).

CONCLUSION

SWE can be used to reliably evaluate the stiffness of the terminal ileum mesentery in normal subjects.

Perioperative optimization of Crohn's disease

Crohn's disease (CD) is a chronic inflammatory disease mainly affecting the gastrointestinal tract. With the increased availability of modalities in the last two decades, the treatment of CD has advanced remarkably. Although medical treatment is the mainstay of therapy, most patients require surgery during the course of their illness, especially those who experience complications. Nutritional optimization and ERAS implementation are crucial for patients with CD who require surgical intervention to reduce postoperative complications. The increased surgical risk was found to be associated with the use of corticosteroids, but the association of surgical risk with immunomodulators, biologic therapy, such as anti-TNF mediations, anti-integrin medications, and anti-IL 12/23 was low in certainty. Decisions about preoperative medication must be made on an individual case-dependent basis. Preoperative imaging studies can assist in the planning of appropriate surgical strategies and approaches. However, patients must be informed of any alterations to their treatment. In summary, the management of perioperative medications and surgery-related decision-making should be individualized and patient-centered based on a multidisciplinary approach.

Anti-TNF Therapies Suppress Adipose Tissue Inflammation in Crohn’s Disease

Anti-TNF biologics have been shown to markedly improve the quality of life for patients with Crohn’s disease (CD), yet one-third of patients fail to benefit from this treatment. Patients with CD develop a characteristic wrapping of visceral adipose tissue (VAT) in the inflamed intestinal area, termed creeping fat, and it is known that adipose tissue expansion influences the efficacy of anti-TNF drugs. We questioned whether anti-TNF therapies impact the creeping fat in CD, which might affect the outcome of the disease. Adipose tissue biopsies were obtained from a cohort of 14 patients with CD that received anti-TNF drugs and from 29 non-anti-TNF-treated patients (control group) matched by sex, age, and body mass index undergoing surgical interventions for symptomatic complications. We found that anti-TNF therapies restored adipose tissue morphology and suppressed immune cell infiltration in the creeping fat. Additionally, anti-TNF treatments appeared to markedly improve the pro-inflammatory phenotype of adipose-tissue macrophages and adipose-tissue-derived stem cells. Our study provides evidence that anti-TNF medications influence immune cells and progenitor cells in the creeping of patients with CD, suppressing inflammation. We propose that perilesional VAT should be considered when administering anti-TNF therapy in patients with CD.

Mesenteric abnormalities play an important role in grading intestinal fibrosis in patients with Crohn's disease: a computed tomography and clinical marker-based nomogram

BACKGROUND

While the grading of intestinal fibrosis is closely related to the therapeutic strategy of patients with Crohn's disease (CD), it has not yet been well resolved. Mesenteric abnormalities are inextricably linked to intestinal fibrosis.

OBJECTIVES

We aimed to establish an optimal model for assessing intestinal fibrosis using computed tomography enterography (CTE) and clinical markers.

DESIGN

A total of 174 patients with CD between January 2014 and June 2020 were included in this retrospective multicentre study.

METHODS

All patients underwent CTE within 3 months prior to surgery. Intestinal fibrosis was pathologically scored as non-mild or moderate-to-severe. Selected imaging of the intestinal walls and mesentery and/or clinical factors were used to develop the diagnostic models. The area under the receiver operating characteristic curve (AUC) analysis was used to evaluate the discrimination performance of the models. A decision curve analysis was performed to evaluate the clinical usefulness of the models.

RESULTS

One-, two-, and three-variable models were identified as possible diagnostic models. Model 1 [mesenteric creeping fat index (MCFI)], Model 2 (mesenteric oedema and MCFI), and Model 3 (mesenteric oedema, MCFI, and disease duration) were established. The AUCs of Model 1 in training and test cohorts 1 and 2 were 0.799, 0.859, and 0.693, respectively; Model 2 was 0.851, 0.833, and 0.757, respectively; and Model 3 was 0.832, 0.821, and 0.850, respectively. We did not observe any significant difference in diagnostic performance between the training and total test cohorts in any model (all p > 0.05). The decision curves showed that Model 3 had the highest net clinical benefit in test cohort 2. The nomogram of this optimal model was constructed by considering the favourable and robust performance of Model 3.

CONCLUSION

A nomogram integrating mesenteric abnormalities on CTE with a clinical marker was optimal for differentiating between non-mild and moderate-to-severe fibrosis in patients with CD.

Radiology of the Mesentery

The recent description and re-classification of the mesentery as an organ prompted renewed interest in its role in physiological and pathological processes. With an improved understanding of its anatomy, accurately and reliably assessing the mesentery with non-invasive radiological investigation becomes more feasible. Multi-detector computed tomography is the main radiological modality employed to assess the mesentery due to its speed, widespread availability, and diagnostic accuracy. Pathologies affecting the mesentery can be classified as primary or secondary mesenteropathies. Primary mesenteropathies originate in the mesentery and subsequently progress to involve other organ systems (e.g., mesenteric ischemia or mesenteric volvulus). Secondary mesenteropathies describe disease processes that originate elsewhere and progress to involve the mesentery with varying degrees of severity (e.g., lymphoma). The implementation of standardized radiological imaging protocols, nomenclature, and reporting format with regard to the mesentery will be essential in improving the assessment of mesenteric anatomy and various mesenteropathies. In this article, we describe and illustrate the current state of art in respect of the radiological assessment of the mesentery.

Aspects Towards the Anastomotic Healing in Crohn’s Disease: Clinical Approach and Current Gaps in Research

Anastomotic leakage is a major complication in gastrointestinal and colorectal surgery and its occurrence increases morbidity and mortality. Its incidence is even higher in Crohn’s disease surgeries. Several authors have identified factors involved in the pathophysiology of anastomotic leak in the literature, aiming to reduce its occurrence and, therefore, improve its surgical treatment. Surgical technique is the most discussed topic in studies on guiding the performance of side-to-side stapled anastomosis. Preoperative nutritional therapy also has been shown to reduce the risk of anastomotic leakage. Other factors remain controversial – immunomodulator use and biologic therapy, antibiotics, and gut microbiota – with studies showing a reduction in the risk of complication while other studies show no correlation. Although mesenteric adipose tissue has been related to disease recurrence, there is no evidence in the literature that it is related to a higher risk of anastomotic leakage. Further exploration on this topic is necessary, including prospective research, to support the development of techniques to prevent anastomotic leakage, in this way benefiting the inflammatory bowel disease patients who have to undergo a surgical procedure.

Constrictive and Hypertrophic Strictures in Ileal Crohn's Disease

BACKGROUND & AIMS

Strictures in Crohn's disease (CD) are classically attributed to fibromuscular hypertrophy of the intestinal wall. We have identified and characterized CD-related ileal strictures that result instead from mural constriction (ie, reduced external circumference).

METHODS

Twenty-four strictures and internal controls from 17 adults with obstructive CD were analyzed by cross-sectional morphometry.

RESULTS

The stricture-to-control circumference ratios (CRs) ranged from 0.53 to 1.7. Six strictures with CR ≥1.0, designated hypertrophic, had concentrically thickened walls, mean 3-fold increases in cross-sectional area and stainable fibromucular tissue, and high transmural inflammation scores. In contrast, 18 strictures with CR <1.0, designated constrictive, had thin, pliant walls, cross-sectional areas and stainable fibromuscular tissue comparable with control values, and low transmural inflammation scores. Eight mildly constrictive strictures also showed mild fibromuscular mural expansion that fell short of statistical significance. Twelve of 18 constrictive strictures (67%) occurred multiply (2-4 strictures per specimen) in contrast with hypertrophic strictures, all of which occurred singly (P = .01). Constriction correlated quantitatively with circumferential serosal fat wrapping (P = .003) and was associated with myenteric lymphocytic plexitis (P = .02). Disease duration was shortest among subjects with constrictive strictures and correlated with increasing circumference (CR ≤0.8, 6.3 ± 6.2 years; CR >0.8, 8.7 ± 6.4 years; and CR ≥1.00, 13.7 ± 5.0 years, respectively; P = .03).

CONCLUSIONS

Constrictive ileal strictures in CD differ pathologically and clinically from hypertrophic strictures, featuring little or no fibromuscular mural expansion, frequent multiplicity, and earlier onset. Mesenteric fat wrapping and myenteric plexitis may contribute to their pathogenesis. Pathologic manifestations of constriction and hypertrophy can coexist, suggesting that stricture heterogeneity may be shaped in part by the dynamics of constrictive and hypertrophic processes.

Intriguing Role of the Mesentery in Ileocolic Crohn's Disease

Crohn's disease (CD) is a chronic relapsing inflammatory bowel disease with unknown etiology. Up to 80% of patients will eventually require surgery throughout their lifetime, and often repeated resections are required for disease recurrence. Observations of “creeping fat” surrounding the diseased intestine renewed interest in the mesentery, recently defined as an organ with endocrine and immune functions. According to the inside-out model, the mesentery may be primarily affected in CD and subsequent cause alterations in the mucosa. Recently, lower surgical recurrence rates have been reported with en-bloc excision of the mesentery adjoining the diseased intestine. Results of ongoing randomized controlled trials may clarify the role of the mesentery in CD and possibly lead to its adoption as standard during surgery for Crohn's disease.

Has the Removing of the Mesentery during Ileo-Colic Resection an Impact on Post-Operative Complications and Recurrence in Crohn’s Disease? Results from the Resection of the Mesentery Study (Remedy)

Some evidence suggests a reduction in clinical and surgical recurrence after mesenteric resection in Crohn’s Disease (CD). The aim of the REsection of the MEsentery StuDY (Remedy) was to assess whether mesenteric removal during surgery for ileocolic CD has an impact in terms of postoperative complications, endoscopic and ultrasonographic recurrences, and long-term surgical recurrence. Among the 326 patients undergoing primary resection between 2009 and 2019 in two referral centers, in 204 (62%) the mesentery was resected (Group A) and in 122 (38%) it was retained (Group B). Median follow-up was 4.7 ± 3 years. Groups were similar in the peri-operative course. Endoscopic and ultrasonographic recurrences were 44.6% and 40.4% in Group A, and 46.7% and 41.2% in Group B, respectively, without statistically significant differences. The five-year time-to-event estimates, compared with the Log-rank test, were 3% and 4% for normal or thickened mesentery (p = 0.6), 2.8% and 4% for resection or sparing of the mesentery (p = 0.6), and 1.7% and 5.4% in patients treated with biological or immunosuppressants versus other adjuvant therapy (p = 0.02). In Cox’s model, perforating behavior was a risk factor, and biological or immunosuppressant adjuvant therapy protective for surgical recurrence. The resection of the mesentery does not seem to reduce endoscopic and ultrasonographic recurrences, and the five-year recurrence rate.

Prevalence and significance of mesentery thickening and lymph nodes enlargement in Crohn's disease

BACKGROUND

Mesentery thickening and enlarged lymphnodes are typical findings of Crohn's disease (CD), but their role is unknown. Aim of the present study was to evaluate their prevalence and significance on postoperative complications and long-term surgical recurrence after CD surgery.

METHODS

1272 consecutive, unselected patients were retrospectively reviewed, divided into 4 groups based on the presence or absence of a thickened mesentery and enlarged lymphnodes, and stratified for primary or recurrent surgical procedure. In all patients but those treated with strictureplasty the mesentery and lymphnodes were removed. Patients' characteristics, peri-operative findings, and long-term recurrence were compared by univariate and multivariate analysis.

RESULTS

Thickened mesentery and enlarged lymphnodes were not present in all cases, were typical of ileal location and penetrating behaviour, had a constant decrease over recurrences, were independent of either pre-operative medical therapy or surgical approach, did not increase the duration of surgery and complications, presented similar 20-years recurrence rate to normal mesentery and lymphnodes. Lymphopathy was associated to a worst nutritional status during disease recurrences. At multivariate analysis, age, location, and behaviour, but not mesenteric characteristics, were related to an increased risk of surgical recurrence.

CONCLUSIONS

This study provides new information on mesentery and lymphnodes in CD patients. Further studies are needed to clarify the appropriate surgical approach.

Non-conventional Versus Conventional Strictureplasties for Crohn's Disease. A Systematic Review and Meta-analysis of Treatment Outcomes

BACKGROUND

Strictureplasties [SXP] represent an alternative to bowel resection in Crohn's disease [CD]. Over the years, there has been growing interest in the role of non-conventional SXP for the treatment of extensive CD. A systematic review was performed on complications and recurrence following conventional and non-conventional SXP.

METHODS

The available literature was screened according to the PRISMA statement, until June 2020. Results were categorised into three groups: studies reporting on conventional SXPs; studies with a mixed cohort of conventional and non-conventional SXPs [% non-conventional SXPs ≤15%]; and studies reporting on non-conventional SXPs. Considered endpoints were postoperative complications and overall and SXP site-specific surgical recurrence. Random-effect meta-analysis and meta-regression were used to obtain and compare combined estimates between groups.

RESULTS

A total of 26 studies for a total of 1839 patients with CD were included. The pooled postoperative complication rates were was 15.5% (95% confidence interval [CI] 11.2%-20.3%), 7.4% [95% CI 0.2%-22.9%], and 19.2% [95% CI 5-39.6%] for the three groups, respectively. The rates of septic complications were 4% [95% CI 2.2%-6.2%], 1.9% [95% CI 0.4%-4.3%], and 4.2% [95% CI 0.9%-9.8%], respectively. Cumulative overall surgical recurrence rates were 27.5% [95% CI 18.5%-37.6%], 13.2% [95% CI 8.6%-18.7%], and 18.1% [95% CI 6.8%-33.3%]; and SXP site-specific surgical recurrence rates were 13.2% [95% CI 6.9%-21.2%], 8.3% [95% CI 1.6-19.3%], and 8.8% [95% CI 2.2%-19%], respectively. Formal comparison between the groups revealed no differences.

CONCLUSIONS

Non-conventional SXP did not differ from conventional SXP with respect to safety and long-term recurrence. Consistent heterogeneity was observed and partially limits the conclusions of this study.

[Strictureplasty or resection? Optimal approach for fibrostenotic Crohn's disease]

The indications for surgical intervention in patients with Crohn's disease (CD) are ineffective therapy and complications of this disease. In case of fibrostenotic CD, strictureplasty or bowel resection are indicated. The indications for organ-sparing surgeries are multiple small bowel lesions, previous surgery for CD and short bowel syndrome. Strictureplasty is not advisable in patients with fistulas, abscesses, bowel perforation and severe hypoalbuminemia due to extremely high risk of anastomotic leakage. Therefore, bowel resection is recommended if strict indications for various types of strictureplasty are absent. This approach is associated with effective maintenance of remission and longer recurrence-free period.

Mesenteric Excision and Exclusion for Ileocolic Crohn's Disease: Feasibility and Safety of an Innovative, Combined Surgical Approach With Extended Mesenteric Excision and Kono-S Anastomosis

INTRODUCTION

Ileocolic resection for Crohn's disease traditionally does not include a high ligation of the ileocolic pedicle, and most commonly is performed with a stapled side-to-side ileocolic anastomosis. The mesentery has recently been implicated in the pathophysiology of Crohn's disease. Two techniques have been developed and are associated with reduced postoperative recurrence: the Kono-S anastomosis that excludes diseased mesentery and extended mesenteric excision that resects diseased mesentery. We aimed to assess the technical feasibility and safety of a novel combination of techniques: mesenteric excision and exclusion.

TECHNIQUES

This initial report is a single-center descriptive study of consecutive adults who underwent mesenteric excision and exclusion for primary or recurrent ileocolic Crohn's disease from September 2020 to June 2021. Medication exposure and endoscopic balloon dilation before surgery were recorded. Phenotype was classified using the Montreal Classification. Thirty-day outcomes were reported. A video of the mesenteric excision and exclusion including the Kono-S anastomosis is presented.

RESULTS

Twenty-two patients with ileocolic Crohn's disease underwent mesenteric excision and exclusion: 100% had strictures, 59% had fistulas, 81% were on biologics, and 27% had previous ileocolic resection(s). Seventy-two percent underwent laparoscopic procedures, a mesenteric defect was closed in 86%, omental flaps were fashioned in 77%, and 3 patients were diverted. Median operative time was 175 minutes. Median postoperative stay was 4 days. At 30 days, there were 2 readmissions for reintervention: 1 seton placement and 1 percutaneous drainage of a sterile collection. There were no cases of intra-abdominal sepsis or anastomotic leak.

CONCLUSIONS

Mesenteric excision and exclusion represents an innovative, progressive, and promising approach that appears to be highly feasible and safe. Further study is warranted to determine if mesenteric excision and exclusion is associated with reduced postoperative recurrence of ileocolic Crohn's disease.

What's New in the Postoperative Management of Crohn's Disease?

Patients with Crohn's disease (CD) often require surgical resection due to complications, such as strictures and abscesses, or disease refractory to medical therapy. To understand the evolving management of patients with CD after surgery, we outline the risk factors for postoperative recurrence, advances in postoperative endoscopic evaluation and characterization of recurrence, noninvasive methods of assessing postoperative recurrence, use of postoperative prophylactic medical therapy including newer biologics, and novel surgical methods to reduce postoperative recurrence. The Rutgeerts score (RS) was developed to predict progression of disease based on endoscopic appearance postoperatively and to guide medical therapy. However, this scoring system groups ileal and anastomotic lesions into the same category. A modified RS was developed to separate lesions isolated to the anastomosis and those in the neo-terminal ileum to further understand the role of anastomotic lesions in CD progression. Additional scoring systems have also been evaluated to better understand these differences. In addition, noninvasive diagnostic methods, such as small bowel ultrasound, have high sensitivity and specificity for the detection of postoperative recurrence and are being evaluated as independent methods of assessment. Studies have also shown a reduction in endoscopic recurrence with postoperative anti-TNFα therapy. However, preoperative exposure to anti-TNFα therapy may impact postoperative response to these medications, and therefore, determining optimal postoperative prophylaxis strategy for biologic-experienced patients requires further exploration. Lastly, new surgical modalities to reduce postoperative recurrence are currently being investigated with preliminary data suggesting that an antimesenteric functional end-to-end anastomosis (Kono-S) may decrease postoperative recurrence.

Surgical Strategies to Reduce Postoperative Recurrence of Crohn's Disease After Ileocolic Resection

Postoperative recurrence after ileocaecal resection for fibrostenotic terminal ileal Crohn's disease is a significant issue for patients as it can result in symptom recurrence and requirement for further surgery. There are very few modifiable factors, aside from smoking cessation, that can reduce the risk of postoperative recurrence. Until relatively recently, the surgical technique used for resection and anastomosis had little or no impact on postoperative recurrence rates. Novel surgical techniques such as the Kono-S anastomosis and extended mesenteric excision have shown promise as ways to reduce postoperative recurrence rates. This manuscript will review and discuss the evidence regarding a range of surgical techniques and their potential role in reducing disease recurrence. Some of the techniques have been shown to be associated with significant benefits for patients and have already been integrated into the routine clinical practice of some surgeons, while other techniques remain under investigation. Current techniques such as resection of the mesentery close to the intestine and stapled side to side anastomosis are being challenged. It is looking more likely that surgeons will have a major role to play when it comes to reducing recurrence rates for patients undergoing ileocaecal resection for Crohn's disease.

Laparoscopic vs open surgery in ileostomy reversal in Crohn’s disease: A retrospective study

BACKGROUND

Although minimally invasive surgery is becoming more commonly applied for ileostomy reversal (IR), there have been relatively few studies of IR for patients with Crohn's disease (CD). It is therefore important to evaluate the potential benefits and risks of laparoscopy for patients with CD.

AIM

To compare the safety, feasibility, and short-term and long-term outcomes of laparoscopic IR (LIR) vs open IR (OIR) for the treatment of CD.

METHODS

The baseline characteristics, operative data, and short-term (30-d) and long-term outcomes of patients with CD who underwent LIR and OIR at our institution between January 2017 and January 2020 were retrieved from an electronic database and retrospectively reviewed.

RESULTS

Of the 60 patients enrolled in this study, LIR was performed for 48 and OIR for 12. There were no statistically significant differences in baseline characteristics, operation time, intraoperative blood loss, days to flatus and soft diet, postoperative complications, hospitalization time, readmission rate within 30 d, length of hospitalization, hospitalization costs, or reoperation rate after IR between the two groups. However, patients in the LIR group more frequently required lysis of adhesions as compared to those in the OIR group (87.5% vs 41.7%, respectively, P < 0.05). Notably, following exclusion of patients who underwent enterectomy plus IR, OIR was more advantageous in terms of postoperative recovery of gastrointestinal function and hospitalization costs.

CONCLUSION

The safety and feasibility of LIR for the treatment of CD are comparable to those of OIR with no increase in intraoperative or postoperative complications.

Update on the mesentery: structure, function, and role in disease

Over the past 5 years, systematic investigation of the mesenteric organ has expanded and shown that the mesentery is the organ in and on which all abdominal digestive organs develop and remain connected to. In turn, this observation has clarified the anatomical foundation of the abdomen and the fundamental order at that level. Findings related to the shape and development of the mesentery have illuminated its function, advancing our understanding of the pathobiology, diagnosis, and treatment of several abdominal and systemic diseases. Inclusion of the mesentery in surgical resections alters the course of benign and malignant diseases. Mesenteric-based scoring systems can enhance the radiological interpretation of abdominal disease. Emerging findings reconcile observations across scientific and clinical fields and have been assimilated into reference curricula and practice guidelines. This Review summarises the developmental, anatomical, and clinical advances made since the mesentery was redesignated as an organ in 2016.

Visceral adiposity and inflammatory bowel disease

BACKGROUND

Rates of obesity are increasing worldwide, as is the incidence of inflammatory bowel disease (IBD). Obesity is now considered an inflammatory state. Visceral adiposity in particular may be associated with a more severe inflammatory phenotype in IBD.

AIM

The aim of this review article is to summarise the current literature on the association between visceral adiposity and outcomes in inflammatory bowel disease METHODS: To collect relevant articles, PubMed/MEDLINE and Embase searches were performed using Boolean search phrases. Grey literature and manual searches were also performed. Abstracts were selected by two independent reviewers based on pre-determined criteria. Full text articles were reviewed, and data extracted and assessed.

RESULTS

One hundred twenty-seven abstracts were obtained through the initial search, with 85 abstracts reviewed and 22 full text articles included. Characteristics are included in Table 1. Most of these were retrospective studies and of moderate or weak quality. Studies suggested visceral fat content is higher in Crohn's disease than in healthy controls. Visceral adiposity was associated with an increased risk of complex Crohn's disease phenotype (OR 26.1 95% CI 2-75.4; p = 0.02). Post-operative recurrence was higher in patients with higher visceral fat indices (RR 2.1; CI 1.5-3; p = 0.012). There were conflicting data regarding the effect of visceral adiposity on post-operative complications and the efficacy of medical therapy. Table 1 Study characteristics Author Year Country Study type Study numbers Control group Disease type Methodology e.g. CT Body composition measurements Results Argeny [24] 2018 Austria Retrospective cohort N = 95 N/A Crohn's disease CT; L3 level Visceral fat area (cm²) Visceral fat index (VFA/m²) No association between VFA or VFI and short-term post-operative outcomes Bryant [30] 2018 Australia Prospective cohort N = 110 N/A Crohn's disease and UC DXA Visceral adipose tissue (VAT) (cm³) Visceral adipose tissue (grams) VAT/height index (cm³/m²) VAT:subcutaneous adipose tissue ratio Fat mass index (kg/m²) VAT and VHI increased significantly over 24 months Bryant [13] 2018 Australia Prospective cohort N = 72 N/A Crohn's disease; female DXA Visceral adipose tissue (VAT) (cm³) Visceral adipose tissue (grams) VAT/height index (cm³/m²) VAT:subcutaneous adipose tissue ratio VAT:SAT positively associated with stricturing disease Adiposity not associated with fistulising disease phenotype VAT:SAT significantly associated with faecal calprotectin in L3 phenotype VAT:SAT significantly negatively associated with VHI and QoL over 24 months Buning [25] 2015 Germany Case control N = 50 N = 19 healthy controls Crohn's disease MRI US VAT Thickness of abdominal fat Distance to posterior wall of aorta Area of inferior part of perirenal fat VAT accumulation was higher in CD patients vs healthy controls VAT and VAT/fat mass ratio higher in patients in short-term remission vs long-term remission VAT/FM higher in stricturing/fistulising disease vs inflammatory subtype No association between VAT/FM and CDAI, HBI or anti-TNF treatment Connolly [26] 2014 US Retrospective cohort N = 143 N/A Crohn's disease CT (L1-L5 level) Visceral/intra-abdominal adiposity (VA) Subcutaneous adiposity (SA) VA not associated with post-operative morbidity Decreased SA and increased visceral/subcutaneous ratio were predictive of post-op complications. (p = 0.02; p < 0.001) Cravo [27] 2017 Portugal Retrospective cohort N = 71 N/A Crohn's disease CT (L3 level) Smooth muscle area (cm²) Visceral fat area (cm²) Subcutaneous fat area (cm²) Visceral fat index Muscle radiation attenuation L2 phenotype associated with lower muscle attenuation and higher visceral fat index (non-significant) B2/B3/surgery - significantly lower muscle attenuation. VFI associated with increased risk of complicated phenotype. (OR 26.1; 95% CI 1-75; p = 0.02) Ding [17] 2016 US Retrospective cohort N = 164 N/A Crohn's disease CT (L3 level) Visceral fat area (cm²) Subcutaneous fat area Total fat area Visceral obesity associated with longer duration of surgery, increased intra-operative blood loss and longer length of bowel resected Higher complication rates in patients with visceral obesity (p < 0.001) VFA independent risk factor of adverse post-op outcomes Ding [14] 2017 Retrospective cohort N = 106 N/A Crohn's disease CT (L3 level) Visceral fat area Subcutaneous fat area Skeletal muscle area Skeletal muscle index Visceral obesity and myopenic obesity not significantly associated with risk of primary non-response Body composition factors not associated with secondary loss of response Erhayiem [18] 2011 UK Retrospective cohort N = 50 N/A Crohn's disease CT (L4 level) Mesenteric fat index (visceral:subcutaneous area ratio)N = 50 Mesenteric fat index was significantly higher in complicated Crohn's disease. ROC analysis for MFI in identifying complicated Crohn's disease: AUC = 0.95 (95% CI 0.89-1.0) Feng [28] 2018 China Retrospective cohort N = 80 Non-IBD GI patients Crohn's disease CT-energy spectral Visceral fat area (cm²) Subcutaneous fat area (cm²) Mesenteric fat index No significant difference in VFA between Crohn's disease cohort and control group. (p = 0.669). ROC analysis: detection of disease based on VFA and MFI: AUC 0.776 Sensitivity 77.5% Specificity 67.5% Hafraoui [16] 1998 France/Belgium Prospective N = 43 Healthy volunteers n = 13 Intestinal resection n = 9 Crohn's disease MRI (umbilicus) Total abdominal fat (cm²) Intra-abdominal fat (cm²) Subcutaneous fat (cm²) Ratio of intra-abdominal:total fat area was significantly higher in patients with Crohn's vs controls. (p = 0.012) No correlation between abdominal fat tissue and disease activity, duration or steroid therapy Holt [29] 2017 Australia/New Zealand RCT N = 44 N = 11 placebo group Crohn's disease CT/MRI (L3, L4-5 levels) Visceral adipose tissue area Subcutaneous adipose tissue area Skeletal muscle area Visceral adipose tissue/height index VHI > 1.5 times gender mean was specific for endoscopic recurrence (100%) with sensitivity of 29%. PPV = 1 (0.59-1.00) There was no significant difference in disease activity at 18 months post-resection based on VHI > 1.5 gender mean Li [31] 2015 China Retrospective cohort N = 72 N/A Crohn's disease CT (umbilicus) Visceral fat area (cm²) Subcutaneous fat area (cm²) Mesenteric fat index Post-op recurrence was more frequent with high VFA values. (p = 0.019) VFA and MFI were independent risk factors for post-operative recurrence. (p = 0.013 and p = 0.028, respectively) High VFA and high MFI were significantly higher in patients with endoscopic activity (p = 0.023) Liu [32] 2016 Retrospective case-control N = 59 N = 30 (< 15% increase VFA) IBD with IPAA CT (L3) Visceral fat area Subcutaneous fat area No difference in pouchitis, pouch sinus formation and composite adverse pouch outcomes between the 2 groups with and without VFA increase > 15%. Excessive VAT gain was an independent risk factor for the composite adverse pouch outcomes. (OR 12.6 (95% CI 1.19-133.5) Magro [33] 2018 Brazil Cross-sectional study N = 78 N = 28 Health control Crohn's disease DEXA Fat and lean masses Visceral fat (kg) Visceral fat/BMI Visceral fat per %body fat VF was higher in Crohn's disease group (p = 0.004) compared to controls Parmentier-Decrucq [34] 2009 Prospective study N = 132 N/A Crohn's disease MRI Subcutaneous fat Visceral fat Total abdominal fat increased 18% in Crohn's disease patients treated with infliximab induction therapy Shen [35] 2018 China Retrospective N = 97 N/A Crohn's disease CT (umbilicus) Subcutaneous fat area Visceral fat area Mesenteric fat index VFA and MFI were significantly lower in patients with mucosal healing (post-infliximab). (p < 0.0001) SFA was not significantly different VFA correlated with CDAI (p < 0.001) and was an independent predictive factor for mucosal healing Stidham [15] 2015 Retrospective N = 269 N/A Crohn's disease CT(T10-L5) Subcutaneous fat volume Visceral fat volume No significant difference in visceral fat volume between patients with surgical complications Thiberge [36] 2018 France Retrospective N = 149 N/A Crohn's disease CT (L3 level) Skeletal muscle index Visceral adiposity index Subcutaneous adiposity index SAI and VAI were significantly lower in patients who underwent surgery or who died in 6 months post-CT(p = 0.009 and p < 0.001) VanDerSloot [37] 2017 Cohort study N/A Crohn's disease CT (T11-S5) Visceral adipose tissue volume Non-significant trend toward increased risk of surgery and penetrating disease with increasing VAT Wei [38] 2018 China Retrospective N = 86 N/A IBD post-resection CT (L3 level) Visceral adipose volume Subcutaneous adipose volume Increased visceral:subcutaneous fat ratio was associated with increased procalcitonin levels on post-op days 1, 3 and 5 Yadav [39] 2017 India Prospective N = 97 N/A IBD CT (L4 level) Visceral fat area Subcutaneous fat area No statistically significant correlation between visceral fat and disease behaviour in Crohn's disease N/A not applicable, VFA visceral fat area, VFI visceral fat index, VAT visceral adipose tissue, VHI visceral adipose tissue to height index, SAT subcutaneous adipose tissue, DXA dual-energy X-ray absorptiometry, CT computer tomography, MRI magnetic resonance imaging, US ultrasound, CDAI Crohn's disease activity index, HBI Harvey-Bradshaw Index, anti-TNF anti-tumour necrosis factor, SA subcutaneous adiposity, ROC receiver operating curve, AUC area under the curve, MFI mesenteric fat index, SAI subcutaneous adiposity index, PPV positive predictive value CONCLUSION: Visceral adiposity appears to be increased in Crohn's disease with some evidence that it is also associated with more complex disease phenotypes. There is also a signal that post-operative recurrence rates are affected by increasing mesenteric adiposity. There is a relative lack of data in UC patients and further high-quality studies are necessary to elucidate the relationship between visceral adiposity and IBD and the implications for patient outcomes.

Role of Extended Mesenteric Excision in Postoperative Recurrence of Crohn's Colitis: A Single-Center Study

INTRODUCTION

The mesentery is involved in Crohn's disease. The impact of the extent of mesenteric resection on postoperative disease progression in Crohn's disease remains unconfirmed. This study aimed to determine the association between resection of the mesentery and postoperative outcomes in patients with Crohn's colitis (CC) undergoing colorectal surgery.

METHODS

Patients with CC who underwent colorectal resection between January 2000 and December 2018 were reviewed, and the data were gathered from a prospectively maintained database. Patients were divided into 2 groups according to the extent of mesenteric resection, the extensive mesenteric excision (EME) group and the limited mesenteric excision (LME) group. Outcomes including early postoperative morbidities and surgical recurrence were compared between the 2 groups.

RESULTS

Of the 126 patients included, 60 were in the LME group and 66 in the EME group. There was no significant difference between the 2 groups in early postsurgical outcomes except the intraoperative blood loss was increased in the LME group (P = 0.002). Patients in the EME group had a longer postoperative surgical recurrence-free survival time when compared with those in the LME group (P = 0.01). LME was an independent predictor of postoperative surgical recurrence (hazard ratio 2.67, 95% confidence interval 1.04-6.85, P = 0.04). This was further confirmed in the subgroup analysis of patients undergoing colorectal resection and anastomosis (hazard ratio 2.83, 95% confidence interval 1.01-7.96, P = 0.048).

DISCUSSION

In patients undergoing surgery for CC, inclusion of the mesentery is associated with similar short-term outcomes and improved long-term outcomes compared with those seen when the mesentery is retained.

Surgical features to reduce anastomotic recurrence of Crohn's disease that requires reoperation: a systematic review

Anastomotic recurrence after intestinal resection is one of the main embarrassing problems encountered during Crohn's disease (CD) management. This complication is often associated with an expected consequence, mainly a multiple intestinal resection. This systematic review evaluates published evidence on surgical features to reduce surgical recurrence after bowel resection and provide surgeons with recommendations based on published evidence. We conducted bibliographic research on September 05, 2020, through PubMed, Cochrane database, and Google scholar. We retained meta-analysis, randomized clinical trials, and controlled clinical trials. The strength of clinical data and subsequent recommendations were graded according to the Oxford Centre for Evidence-Based Medicine. Fourteen articles were retained. Early resection reduces surgical relapse and the need for additional medical treatment. There was no difference between conventional and laparoscopic bowel resection. Mesenteric excision seems to reduce surgical recurrence. Stapled side-to-side anastomosis reduces surgical recurrence. However, no difference was observed between Kono-S anastomosis ensure at least similar anastomotic recurrence rate compared to conventional anastomosis. Surgical recurrence was reduced after bowel resection when compared to stricturoplasty. There was no difference between the one and two steps resection. Several surgical features have been investigated. Some of them were unanimously found to be effective in lengthening the disease-free relapse. However, others are still controversial.

Ileal Crohn's Disease Exhibits Similar Transmural Fibrosis Irrespective of Phenotype

INTRODUCTION

In Crohn's disease (CD), the assessment of transmural inflammation and fibrosis is of utmost importance. This study aimed to quantify these parameters in CD ileal specimens and correlate them with disease progression.

METHODS

This is a retrospective unicentric study based on the analysis of archived specimens (n = 103) of primary ileal resection. Data were retrieved from a prospective national inflammatory bowel disease registry. Two pathologists, blinded for CD phenotype and clinical indications for surgery, examined 3 sections per patient and graded inflammation and fibrosis, based on a histopathological score.

RESULTS

Penetrating (B3, n = 74) CD exhibited significantly higher inflammation in diseased areas, compared with stricturing (B2, n = 29) disease (score 3: 96% vs 76%, P = 0.005 in inflamed areas; 78% vs 55%, P = 0.019 in most affected areas). This was also observed for the comparison of B2 CD with B3 CD with (B3s, n = 54) and without associated stricture (B3o, n = 20): B3s vs B2: 81% vs 55%, P = 0.033 in most affected areas; B3o vs B2: 100% vs 76%, P = 0.006 in inflamed areas; 70% vs 55%, P = 0.039 in most affected areas. We could not show differences in fibrosis scores between the subphenotypes. Postoperative new penetrating events occurred only in B3s (n = 6, 11%, P = 0.043) patients. The changing of biologic therapy after surgery correlated with severe inflammation at the proximal ileal margin (55% changed vs 25% not changed, P = 0.035).

DISCUSSION

In our cohort, fibrosis scores and fibromuscular changes were comparable, irrespective of CD phenotype. Inflammation severity was the major differentiator between penetrating and stricturing disease.JOURNAL/cltg/04.03/01720094-202104000-00012/inline-graphic1/v/2021-04-13T161901Z/r/image-tiff.

Post-surgical recurrence of Crohn's disease: Situational analysis and future prospects

Surgery retains a major role in the treatment of Crohn's disease, and the prevention of post-operative recurrence is an essential issue. In fact, despite the increasing use of biotherapies, almost all of the patients who undergo surgery will present with a recurrence, initially endoscopic and then clinical, eventually leading to a second intervention in 15 to 20% of cases. Certain risk factors for recurrence such as smoking, repeated and/or extensive resections, anoperineal involvement, myenteric plexitis, epithelioid granulomas, penetrating disease behaviour and lack of post-operative prophylactic treatment have been well established. Currently, measures to prevent post-operative recurrence are based mainly on smoking cessation in all patients and the prescription of anti-TNFα medications for patients with a high risk of recurrence (at least two risk factors for recurrence). However, new surgical techniques have recently been described which could modify post-operative prevention strategies. Kono's lateral anti-mesenteric anastomosis could significantly reduce clinical and endoscopic recurrence compared to conventional anastomosis techniques. Long latero-lateral isoperistaltic stricturoplasties have been shown to be feasible and are associated with a low rate of long-term symptomatic recurrence requiring surgery. In a preliminary series, intestinal resections with extensive mesenteric resection reduced the rate of recurrence in comparison with patients operated on conventionally (3% vs. 40% at five years). If the results of these new surgical techniques are confirmed, the indications for post-operative immunomodulatory treatments could be downgraded in patients currently considered to be at high risk of recurrence.

Degree of Creeping Fat Assessed by Computed Tomography Enterography is Associated with Intestinal Fibrotic Stricture in Patients with Crohn's Disease: A Potentially Novel Mesenteric Creeping Fat Index

BACKGROUND AND AIMS

Emerging evidence points to a link between creeping fat and the pathogenesis of Crohn's disease [CD]. Non-invasive assessment of the severity of creeping fat on cross-sectional imaging modality has seldom been investigated. This study aimed to develop and characterize a novel mesenteric creeping fat index [MCFI] based on computed tomography [CT] in CD patients.

METHODS

MCFI was developed based on vascular findings on CT in a retrospective cohort [n = 91] and validated in a prospective cohort [n = 30]. The severity of creeping fat was graded based on the extent to which mesenteric fat extended around the intestinal circumference using the vessels in the fat as a marker. The accuracy of MCFI was assessed by comparing it with the degree of creeping fat observed in surgical specimens. The relationship between MCFI and fibrostenosis was characterized by determining if these correlated. The accuracy of MCFI was compared with other radiographic indices [i.e. visceral to subcutaneous fat area ratio and fibrofatty proliferation score].

RESULTS

In the retrospective cohort, MCFI had moderate accuracy in differentiating moderate-severe from mild fibrostenosis (area under the receiver operating characteristic [ROC] curve [AUC] = 0.799; p = 0.000). ROC analysis in the retrospective cohort identified a threshold MCFI of > 3 which accurately differentiated fibrostenosis severity in the prospective cohort [AUC = 0.756; p = 0.018]. An excellent correlation was shown between MCFI and the extent of fat wrapping in specimens in the prospective cohort [r = 0.840, p = 0.000]. Neither visceral to subcutaneous fat area ratio nor fibrofatty proliferation score correlated well with the degree of intestinal fibrosis.

CONCLUSIONS

MCFI can accurately characterize the extent of mesenteric fat wrapping in surgical specimens. It may become another non-invasive measure of CD fibrostenosis.

The role of Kono-S anastomosis and mesenteric resection in reducing recurrence after surgery for Crohn's disease: a systematic review

AIM

Recurrence after surgery for Crohn's disease is common. Anastomotic configuration may influence recurrence and the mesentery may be key. Recently the Kono-S anastomosis and radical mesenteric excision have been proposed as methods of reducing recurrence. We analysed the literature pertaining to these novel techniques.

METHOD

We searched MEDLINE, Embase and the Cochrane Library for, and selected, studies evaluating Kono-S anastomosis and/or radical mesenteric excision in Crohn's disease. We assessed methodological quality and risk of bias using the Cochrane risk of bias tool for randomized controlled trials and the Joanna Briggs Institute tool for nonrandomized trials. A narrative synthesis was used to summarize the findings.

RESULTS

Nine studies (896 patients) were identified. Apart from one randomized controlled trial with a low risk of bias the overall level of evidence was poor (Grade IV). The Kono-S anastomosis was associated with a lower incidence of endoscopic and surgical recurrence (0%-3.4% vs 15%-24.4% respectively). Complications, particularly anastomotic leak rate, were also lower (1.8% vs 9.3% respectively). Evidence from a single poor quality study suggested that mesenteric excision may reduce surgical recurrence rates compared with mesentery preservation.

CONCLUSION

The existing literature suggests that the Kono-S anastomosis is safe and may reduce endoscopic and surgical recurrence, but level of evidence is mainly poor. One element of the Kono-S technique, preservation of the mesentery, may be detrimental to recurrence. Further, higher quality, studies are required to investigate these techniques. Such studies should consider the impact of the degree of mesenteric resection in addition to the anastomosis on disease recurrence.

Pathophysiology of Crohn's disease inflammation and recurrence

Chron’s Disease is a chronic inflammatory intestinal disease, first described at the beginning of the last century. The disease is characterized by the alternation of periods of flares and remissions influenced by a complex pathogenesis in which inflammation plays a key role. Crohn’s disease evolution is mediated by a complex alteration of the inflammatory response which is characterized by alterations of the innate immunity of the intestinal mucosa barrier together with a remodeling of the extracellular matrix through the expression of metalloproteins and increased adhesion molecules expression, such as MAcCAM-1. This reshaped microenvironment enhances leucocytes migration in the sites of inflammation, promoting a T_H1 response, through the production of cytokines such as IL-12 and TNF-α. IL-12 itself and IL-23 have been targeted for the medical treatment of CD. Giving the limited success of medical therapies, the treatment of the disease is invariably surgical. This review will highlight the role of inflammation in CD and describe the surgical approaches for the prevention of the almost inevitable recurrence.

Mesentery - a 'New' organ

The mesentery is the organ in which all abdominal digestive organs develop, and which maintains these in systemic continuity in adulthood. Interest in the mesentery was rekindled by advancements of Heald and Hohenberger in colorectal surgery. Conventional descriptions hold there are multiple mesenteries centrally connected to the posterior midline. Recent advances first demonstrated that, distal to the duodenojejunal flexure, the mesentery is a continuous collection of tissues. This observation explained how the small and large intestines are centrally connected, and the anatomy of the associated peritoneal landscape. In turn it prompted recategorisation of the mesentery as an organ. Subsequent work demonstrated the mesentery remains continuous throughout development, and that abdominal digestive organs (i.e. liver, spleen, intestine and pancreas) develop either on, or in it. This relationship is retained into adulthood when abdominal digestive organs are directly connected to the mesentery (i.e. they are 'mesenteric' in embryological origin and anatomical position). Recognition of mesenteric continuity identified the mesenteric model of abdominal anatomy according to which all abdominal abdomino-pelvic organs are organised into either a mesenteric or a non-mesenteric domain. This model explains the positional anatomy of all abdominal digestive organs, and associated vasculature. Moreover, it explains the peritoneal landscape and enables differentiation of peritoneum from the mesentery. Increased scientific focus on the mesentery has identified multiple vital or specialised functions. These vary across time and in anatomical location. The following review demonstrates how recent advances related to the mesentery are re-orientating the study of human biology in general and, by extension, clinical practice.

Perioperative management of ileocecal Crohn's disease in the current era

INTRODUCTION

The ileocecal region is most commonly involved in patients with Crohn's disease (CD).

AREAS COVERED

In the management of ileocecal CD, this review discusses the underlying clinical issues with perioperative management and surgical intervention.

EXPERT OPINION

Despite advances in medical treatments, surgery is required in a proportion of patients. Preoperative optimization including weaning of corticosteroids, initiation of enteral feeds, venous thromboembolism prophylaxis and smoking cessation may lead to improved postoperative outcomes. Several surgical approaches regarding anastomotic technique and range of mesentery division are now attempted to reduce the incidence of postoperative recurrence. Disease recurrence is common after surgery for CD. Early endoscopic assessment and subsequent treatment adjustment are optimal strategies for the prevention of recurrence after ileocolonic resection.

Surgical treatment of intestinal stricture in inflammatory bowel disease

Fibroblast infiltration and collagen deposition result in structural changes in the bowel wall, and lead to strictures in intestinal inflammatory disease. While strictures can also occur in other contexts, such as malignancy, this review focuses on the surgical treatment of stricture secondary to inflammatory bowel disease. Distinguishing between predominantly inflammation vs established fibrosis as the cause of a stricture can be challenging. While inflammatory strictures may be responsive to medication, predominantly fibrotic strictures usually need surgical intervention. Both endoluminal and extraluminal approaches are described in this review. Endoscopic dilatation of strictures is suitable for short-segment isolated small bowel strictures. Other options are to divide the stricture surgically but preserve the length, performing a strictureplasty or resecting the strictured segment. The mesentery is increasingly recognized as playing a role in stricture recurrence. In a relapsing-remitting disease such as Crohn's disease, the preservation of intestinal length is essential and balance is needed between this and a complete resection to reduce the risk of recurrence. Pre- and postoperative involvement of the multidisciplinary team is essential to improve outcomes in this challenging clinical scenario.

Video-laparoscopic assessment of the small bowel in Crohn's disease: a comparative study to evaluate surgeons' inter-observer variability

BACKGROUND

Assessment of the entire small bowel is advocated during Crohn's disease (CD) surgery, as intraoperative detection of new lesions may lead to change in the planned procedure. The aim of this study was to evaluate the inter-observer variability in the assessment of extent and severity of CD at the small bowel laparoscopic "walkthrough".

METHODS

A survey on laparoscopic assessment of the small bowel in patients with CD, including items adapted from the MREnterography or ultrasound in Crohn's disease (METRIC) study and from the classification of severity of mesenteric disease was developed by an invited committee of colorectal surgeons. Anonymous laparoscopic videos demonstrating the small bowel "walkthrough" in ileocolonic resection for primary and recurrent CD were distributed to the committee members together with the anonymous survey. The primary outcome was the rate of inter-observer variability on assessment of strictures, dilatations, complications and severity of mesenteric inflammation.

RESULTS

12 assessors completed the survey on 8 small bowel walkthrough videos. The evaluation of the small bowel thickening and of the mesenteric fat wrapping were the most reliable assessments with an overall agreement of 87.1% (k = 0.31; 95% CI - 0.22, 0.84) and 82.7% (k = 0.35; 95% CI - 0.04, 0.73), respectively. The presence of strictures and pre-stenotic dilatation demonstrated agreement of 75.2% (k = 0.06: 95% CI - 0.33, 0.45) and 71.2% (k = 0.33; 95% CI 0.15, 0.51), respectively. Evaluation of fistulae had an overall agreement of 75.3%, while there was a significant variation in the evaluation of mild, moderate and severe mesenteric disease with overall agreement ranging from 33.3 to 100%.

CONCLUSION

Laparoscopic assessment of the small bowel thickening and of the presence of mesenteric fat wrapping is reliable for the intraoperative evaluation of CD with high inter-rater agreement. There is significant heterogeneity in the assessment of the severity of the mesenteric disease involvement.

Strictureplasty versus bowel resection for the surgical management of fibrostenotic Crohn's disease: a systematic review and meta-analysis

BACKGROUND

Strictureplasty (SPX) conserves bowel length and minimizes the risk of developing short bowel syndrome in patients undergoing surgery for Crohn's disease (CD). However, SPX may be associated with a higher risk of recurrence compared with bowel resection (BR).

AIM

We sought to compare morbidity and recurrence following SPX and BR in patients with fibrostenotic CD.

METHODS

A systematic review was performed according to PRISMA and MOOSE guidelines. Observational studies that compared outcomes of CD patients undergoing either SPX or BR were identified. Log hazard ratios (InHR) for recurrence-free survival (RFS) and their standard errors were calculated from Kaplan-Meier plots or Cox regression models and pooled using the inverse variance method. Dichotomous variables were pooled as odds ratios (OR) using the Mantel-Haenszel method. Continuous variables were pooled as weighted mean differences.

RESULTS

Twelve studies of 1026 CD patients (SPX n = 444, 43.27%; BR with or without SPX n = 582, 56.72%) were eligible for inclusion. There was an increased likelihood of disease recurrence with SPX than with BR (OR 1.61; 95% CI, 1.03, 2.52; p = 0.04; I² = 0%). Patients who had a SPX alone had a significantly reduced RFS than those who underwent BR (HR 1.47; 95% CI, 1.08, 2.01; p = 0.02; I² = 0%). There was no difference in morbidity between the groups (OR 0.58; 95% CI, 0.26, 1.28; p = 0.18; I² = 0%).

CONCLUSION

SPX should only be performed in those patients with Crohn's strictures that are at high risk for short bowel syndrome and intestinal failure; otherwise, BR is the favored surgical technique for the management of fibrostenotic CD.

Meta-analysis of early bowel resection versus initial medical therapy in patient's with ileocolonic Crohn's disease

BACKGROUND

Early bowel resection (EBR) in ileocolonic Crohn's disease (CD) may be associated with more durable remission compared with initial medical therapy (IMT) even when biologic therapy is included.

AIM

To compare the efficacy of EBR versus IMT for ileocolonic CD METHODS: A systematic search was performed to identify studies that compared EBR (performed < 1 year from initial diagnosis) or IMT for the management of ileocolonic CD. Log hazard ratios (InHR) for relapse-free survival (RFS) and their standard errors were calculated from Kaplan-Meier plots and pooled using the inverse-variance method. Dichotomous variables were pooled as odds ratios (OR). Quality assessment of the included studies was performed using the Newcastle-Ottawa (NOS) and Jadad scales.

RESULTS

A total of 7 studies with 1863 CD patients (EBR n = 581, 31.2%; IMT n = 1282, 68.8%) were eligible for inclusion. There was a moderate-to-high risk of bias. The median NOS was 8 (range 7-9). There was a reduced likelihood of overall (OR, 0.53; 95% confidence interval (95% CI), 0.34, 0.83; p = 0.005) and surgical (OR, 0.47; 95% CI, 0.24, 0.91; p = 0.03) relapse with EBR. There was also a less requirement for maintenance biologic therapy (OR, 0.24; 95% CI, 0.14, 0.42; p < 0.0001). Patients who underwent EBR had a significantly improved RFS than those who underwent IMT (HR, 0.62; 95% CI, 0.52, 0.73; p < 0.001). There was no difference in morbidity (OR, 1.67; 95% CI, 0.44, 6.36; p = 0.45) between the groups.

CONCLUSION

EBR may be associated with less relapse and need for maintenance biologic therapy than IMT. 'Upfront' or early resection may represent a reasonable and cost-effective alternative to biologic therapy, especially in biologic-resistant subpopulations.

Mesenteric excision surgery or conservative limited resection in Crohn's disease: study protocol for an international, multicenter, randomized controlled trial

Background

The structures of the mesentery including adipose tissue, nerves, and lymphatics play an important role in the pathogenesis and disease progression of Crohn’s disease (CD). Conventional surgical resection for CD usually does not involve resecting the mesentery en bloc with the specimen. This contrasts with complete mesocolic excision (CME) in colorectal cancer, which involves radical resection of the mesentery. Preliminary evidence from smaller studies suggests that applying the principle of mesocolic excision to CD surgery may reduce the risk of postoperative recurrence. This randomized controlled trial is designed to test whether applying the principles of mesocolic excision to CD results in reduced postoperative recurrence. It also aims to evaluate intra- and postoperative morbidity between the two approaches.

Methods

This international, multicenter, randomized controlled trial will randomize patients (n = 116) scheduled to undergo primary ileocolic resection to either receive extensive mesenteric excision (EME) or conventional ileocolic resection with limited mesenteric excision (LME). Five sites will recruit patients in three countries. In the EME group, the mesentery is resected following CME, while avoiding the root region, i.e., 1 cm from the root of the ileocolic artery and vein. In the LME group, the mesentery is retained, i.e., “close shave” or < 3 cm from the border of bowel. The primary end point will be surgical recurrence after surgery. The secondary end points will be the postoperative endoscopic and clinical recurrence, and intra- and postoperative morbidity. Demographics, risk factors, laboratory investigations, endoscopy, postoperative prophylaxis and imaging examination will be assessed. Analysis of the primary outcome will be on an intention-to-treat basis.

Discussion

If mesocolic excision in CD reduces postoperative disease recurrence and does not increase morbidity, this trial has the potential to change practice and reduce recurrence of CD after surgical resection.

Trial registration

Clinical Trials.gov, ID: NCT03769922. Registered on February 27, 2019.

Systemic Molecular Mediators of Inflammation Differentiate Between Crohn's Disease and Ulcerative Colitis, Implicating Threshold Levels of IL-10 and Relative Ratios of Pro-inflammatory Cytokines in Therapy

BACKGROUND AND AIMS

Faecal diversion is associated with improvements in Crohn's disease but not ulcerative colitis, indicating that differing mechanisms mediate the diseases. This study aimed to investigate levels of systemic mediators of inflammation, including fibrocytes and cytokines, [1] in patients with Crohn's disease and ulcerative colitis preoperatively compared with healthy controls and [2] in patients with Crohn's disease and ulcerative colitis prior to and following faecal diversion.

METHODS

Blood samples were obtained from healthy individuals and patients with Crohn's disease or ulcerative colitis. Levels of circulating fibrocytes were quantified using flow cytometric analysis and their potential relationship to risk factors of inflammatory bowel disease were determined. Levels of circulating cytokines involved in inflammation and fibrocyte recruitment and differentiation were investigated.

RESULTS

Circulating fibrocytes were elevated in Crohn's disease and ulcerative colitis patients when compared with healthy controls. Smoking, or a history of smoking, was associated with increases in circulating fibrocytes in Crohn's disease, but not ulcerative colitis. Cytokines involved in fibrocyte recruitment were increased in Crohn's disease patients, whereas patients with ulcerative colitis displayed increased levels of pro-inflammatory cytokines. Faecal diversion in Crohn's disease patients resulted in decreased circulating fibrocytes, pro-inflammatory cytokines, and TGF-β1, and increased IL-10, whereas the inverse was observed in ulcerative colitis patients.

CONCLUSIONS

The clinical effect of faecal diversion in Crohn's disease and ulcerative colitis may be explained by differing circulating fibrocyte and cytokine responses. Such differences aid in understanding the disease mechanisms and suggest a new therapeutic strategy for inflammatory bowel disease.