Background: Because of specific methodological difficulties in conducting randomized trials, surgical research remains dependent predominantly on observational or non-randomized studies. Few validated instruments are available to determine the methodological quality of such studies either from the reader's perspective or for the purpose of meta-analysis. The aim of the present study was to develop and validate such an instrument. Methods: After an initial conceptualization phase of a methodological index for non-randomized studies (MINORS), a list of 12 potential items was sent to 100 experts from different surgical specialities for evaluation and was also assessed by 10 clinical methodologists. Subsequent testing involved the assessment of inter-reviewer agreement, test-retest reliability at 2 months, internal consistency reliability and external validity. Results:The final version of MINORS contained 12 items, the first eight being specifically for non-comparative studies. Reliability was established on the basis of good inter-reviewer agreement, high test-retest reliability by the κ -coefficient and good internal consistency by a high Cronbach's α -coefficient. External validity was established in terms of the ability of MINORS to identify excellent trials. Conclusions: MINORS is a valid instrument designed to assess the methodological quality of non-randomized surgical studies, whether comparative or non-comparative. The next step will be to determine its external validity when used in a large number of studies and to compare it with other existing instruments.Key words: comparative study, methodology index, non-randomized study.Abbreviation : MINORS, methodological index for non-randomized studies. INTRODUCTIONAlthough surgeons are now conducting an increasing number of randomized trials, 1 most of the available evidence in surgery comes from non-randomized studies, both comparative and noncomparative. Indeed surgical research remains an example of a situation where randomization is not always possible or feasible. 2 Beyond large randomized trials, systematic reviews are an important way to answer questions in surgery. However, the systematic review or meta-analysis of studies other than randomized trials may be difficult because combining the results of observational studies of heterogeneous quality could be highly biased.Observational studies include comparative studies such as case-control and cohort designs, and patient series which may or may not involve comparisons between two or more groups.Several papers have discussed the methodology of metaanalyses of observational studies 3,4 and checklists have been proposed but not formally validated. 5 Downs and Black used clinimetric criteria to develop a checklist which was applicable to both randomized and non-randomized studies without distinction. 6 The aim of the present study was to develop and validate a methodological index for non-randomized studies (MINORS) which could be used by readers, manuscript reviewers or journal editors to assess the quality...

Background: Obesity is a condition with a complex pathophysiology characterized by both chronic low-grade inflammation and changes in the gut microbial ecosystem. These alterations can affect the metabolism of tryptophan (TRP), an essential amino acid and precursor of serotonin (5-HT), kynurenine (KYN), and indoles. This study aimed to investigate alterations in KYN and microbiota-mediated indole routes of TRP metabolism in obese subjects relatively to non-obese controls and to determine their relationship with systemic inflammation. Methods: Eighty-five obese adults (avg. BMI = 40.48) and 42 non-obese control individuals (avg. BMI = 24.03) were recruited. Plasma levels of TRP catabolites were assessed using Ultra High Performance Liquid Chromatography-ElectroSpray-Ionization-Tandem Mass Spectrometry. High-sensitive C-reactive protein (hsCRP) and high-sensitive interleukin 6 (hsIL-6) were measured in the serum as markers of systemic inflammation using enzyme-linked immunosorbent assay. Results: Both KYN and microbiota-mediated indole routes of TRP metabolism were altered in obese subjects, as reflected in higher KYN/TRP ratio and lower 5-HT and indoles levels, relatively to non-obese controls. HsIL-6 and hsCRP were increased in obesity and were overall associated with TRP metabolic pathways alterations. Conclusion: These results indicate for the first time that KYN and indole TRP metabolic pathways are concomitantly altered in obese subjects and highlight their respective associations with obesity-related systemic inflammation.

Abstract STUDY QUESTION What are the risk factors and prevalence of bowel fistula following surgical management of deep endometriosis infiltrating the rectosigmoid and how can it be managed? SUMMARY ANSWER In patients managed for deep endometriosis of the rectosigmoid, risk of fistula is increased by bowel opening during both segmental colorectal resection and disc excision and rectovaginal fistula repair is more challenging than for bowel leakage. WHAT IS KNOWN ALREADY Bowel fistula is known to be a severe complication of colorectal endometriosis surgery; however, there is little available data on its prevalence in large series or on specific management. STUDY DESIGN, SIZE, DURATION A retrospective study employing data prospectively recorded in the North-West Inter Regional Female Cohort for Patients with Endometriosis (CIRENDO) from June 2009 to May 2019, in three tertiary referral centres. PARTICIPANTS/MATERIALS, SETTING, METHODS One thousand one hundred and two patients presenting with deep endometriosis infiltrating the rectosigmoid, who were managed by shaving, disc excision or colorectal resection. The prevalence of bowel fistula was assessed, and factors related to the complication and its surgical management. MAIN RESULTS AND THE ROLE OF CHANCE Of 1102 patients enrolled in the study, 52.5% had a past history of gynaecological surgery and 52.7% had unsuccessfully attempted to conceive for over 12 months. Digestive tract subocclusion/occlusion was recorded in 12.7%, hydronephrosis in 4.5% and baseline severe bladder dysfunction in 1.5%. An exclusive laparoscopic approach was carried out in 96.8% of patients. Rectal shaving was performed in 31.9%, disc excision in 23.1%, colorectal resection in 35.8% and combined disc excision and sigmoid colon resection in 2.9%. For various reasons, the nodule was not completely removed in 6.4%, while in 7.2% of cases complementary procedures on the ileum, caecum and right colon were required. Parametrium excision was performed in 7.8%, dissection and excision of sacral roots in 4%, and surgery for ureteral endometriosis in 11.9%. Diverting stoma was performed in 21.8%. Thirty-seven patients presented with bowel fistulae (3.4%) of whom 23 (62.2%) were found to have rectovaginal fistulae and 14 (37.8%) leakage. Logistic regression model showed rectal lumen opening to increase risk of fistula when compared with shaving, regardless of nodule size: adjusted odds ratio (95% CI) for disc excision, colorectal resection and association of disc excision + segmental resection was 6.8 (1.9–23.8), 4.8 (1.4–16.9) and 11 (2.1–58.6), respectively. Repair of 23 rectovaginal fistulae required 1, 2, 3 or 4 additional surgical procedures in 12 (52.2%), 8 (34.8%), 2 (8.7%) and 1 patient (4.3%), respectively. Repair of leakage in 14 patients required 1 procedure (stoma) in 12 cases (85.7%) and a second procedure (colorectal resection) in 2 cases (14.3%). All patients, excepted five women managed by delayed coloanal anastomosis, underwent a supplementary surgical procedure for stoma repair. The period of time required for diverting stoma following repair of rectovaginal fistulae was significantly longer than for repair of leakages (median values 10 and 5 months, respectively, P = 0.008) LIMITATIONS, REASONS FOR CAUTION The main limits relate to the heterogeneity of techniques used in removal of rectosigmoid nodules and repairing fistulae, the lack of accurate information about the level of nodules, the small number of centres and that a majority of patients were managed by one surgeon. WIDER IMPLICATIONS OF THE FINDINGS Deep endometriosis infiltrating the rectosigmoid can be managed laparoscopically with a relatively low risk of bowel fistula. When the type of bowel procedure can be chosen, performance of shaving instead of disc excision or colorectal resection is suggested considering the lower risk of bowel fistula. Rectovaginal fistula repair is more challenging than for bowel leakage and may require up to four additional surgical procedures. STUDY FUNDING/COMPETING INTEREST(S) CIRENDO is financed by the G4 Group (The University Hospitals of Rouen, Lille, Amiens and Caen) and the ROUENDOMETRIOSE Association. No financial support was received for this study. H.R. reports personal fees from ETHICON, Plasma Surgical, Olympus and Nordic Pharma outside the submitted work. The other authors declare no conflict of interests related to this topic.

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