RObotic Versus LAparoscopic Colectomy for DIverticulitis.

Background Over the past decade, there has been a growing interest in the use of robotic surgery for diverticular disease (DD). The evidence available in the literature is based on retrospective studies and two meta-analyses1,2. To date, the robotic approach offers significant advantages over laparoscopic surgery in terms of conversion rate and shortened hospital stay for the treatment of diverticular disease.

The investigators aimed to evaluate whether elective robotic colectomy may offer some advantages over the laparoscopic approach for surgical treatment of diverticular disease performing a prospective multicenter study.

Methods and Materials This is a multi-center, prospective, not-for-profit cohort study that will enroll patients undergoing elective or delayed urgent surgical treatment for left-sided colonic diverticular disease. The enrollment period will be one year, followed by one year of follow-up. The study will start in Juin 2023.

Data will be collected in a prospective database using an easy to fill out Google form, also available on mobile devices.

Several preoperative, intraoperative and postoperative outcomes will be analyzed.

OUTCOMES Pre-Operative

• Demographic Outcomes: Age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA), Charlson Comorbidity Index (CSI: https://www.mdcalc.com/calc/3917/charlson-comorbidity-index-cci)
• Indications for surgery:
• Complicated DD: colonic stenosis, abscess, fistula, others;
• Recurrent DD: multiple episodes of diverticulitis affecting quality of life;
• Planned vascular ligation (inferior mesenteric artery vs. sigmoid arteries)
• Preoperative bowel preparation
• Indication for minimally invasive approach pursued (Why Rob vs Lap)

Intraoperative

• Surgical approach (laparoscopic or robotic)
• Intraoperative findings (sigmoid stenosis, stricture, adhesion, fistula)
• Intraoperative complications (specify types)
• Conversion to open approach
• Operative times
• Effective vessel ligation
• Splenic flexure mobilization
• Type of colon resection (sigmoidectomy, left colectomy, anterior rectal resection, Hartmann procedure)
• Stoma (ileostomy vs. colostomy)
• Associated procedures
• Specimen extraction (midline, off midline, suprapubic or natural orifice) Postoperative
• 30-day postoperative complications (Clavien-Dindo classification)
• 30-day reoperation
• 30-day readmission
• Length of stay LOS
• Time to return to work (days)
• 30 days - Mortality
• One-year follow-up

Sample size The estimated sample sizes for the study using a proportion of 0.125 for Laparoscopic approach and a proportion of 0.074 for Robotic approach, and a risk of conversion rate OR=0.56 (IC95% 0.45-0.70), is at least 1450 patients (725 for the group - alpha = 0.0500, power = 0.9000, delta = 0.5600). MICE (Multivariate Imputation via Chained Equations) is the procedure used to impute missing data for explanatory variables. In this approach, instead of imputing all missing values with a single value (mean/median), the statistical information is derived from the median), it takes into account the statistical information derived from the distribution of the other variables. The missing values are considered as an outcome to be predicted. This allows to take into account the correct variability in the entire data set and to obtain estimates that are as unbiased as possible.

Statistical Analysis The quantitative variables included in the study are expressed as mean ± standard deviation, median and range (distance between maximum and minimum values), both at the overall level and by surgical approach. The qualitative (categorical) variables are presented as percentages and absolute values, both at a general level and divided by surgical approach. It will be evaluated, if necessary, to perform a propensity score matching procedure between the two approaches (Rob and Lap), using the nearest neighbor matching technique, without replacement. Demographics, pre-operative and intra-operative characteristics are used in the propensity score logistic regression models to minimize selection bias, by assembling a matched cohort in which confounding factors are balanced between the two groups. In the matched cohort bivariate analyses are performed to .compare the primary and secondary outcomes between the two groups.

The comparison between the quantitative variables of interest is performed by the two-tailed Student T-test (in case of heteroskedasticity of variances) or with nonparametric tests, such as the Mann-Whitney U test or theKruskal-Wallis test. The comparison between qualitative variables of interest is carried out to evaluate the association or not between them, through an extension of the chi-square test suitable for multicenter studies (the Cochran - Mantel - Haenszel test).

For the entire cohort multivariate logistic regression models are performed to test the effect of surgical approach on primary and secondary outcomes.

Ethics and dissemination The trial will be conducted in accordance with the Declaration of Helsinki and in compliance with the Good Clinical Practice, Principle E6 (R2). The study will be approved by the Ethics Committee of the coordinating center (Comitato Etico di Area Vasta Sud Est Dipartimento Politiche del Farmaco e Attività Farmaceutiche Segreteria Amministrativa) and then will be registered at ClinicalTrial.gov. Subsequently, all participating centers will receive approval to participate from the local institutional review board. Authorship for written publications will be confirmed for all participating investigators (2 investigators per center). Anonymized participant-level data sets will be made available upon reasonable upon reasonable request by contacting the principal investigator. Study results will be presented at international or national meetings and published in surgical journals.