To report (1) efficacy and (2) safety outcomes comparing extended thromboprophylaxis (ETP) with low molecular weight heparin (LMWH) and direct oral anticoagulants (DOAC) versus no ETP after colorectal surgery. A systematic review using MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials to March 2024. Randomised controlled trials and observational studies investigating ETP with LMWH or DOAC for at least 28 days were included. (1) Efficacy outcome was venous thromboembolism (VTE) rate at 30-days postoperatively. (2) Safety outcomes included major bleeding events at 30–90-days. Odds ratio (OR) and 95

Primary acquired perineal hernia is rare with only 100 reported cases in the literature. Emergency presentations of intestinal obstruction secondary to perineal hernia are very rare and to-date, there are only eight cases reported in the literature. We present a case of a 74-year-old lady who presented with a small bowel obstruction secondary to strangulated perineal hernia in the absence of pelvic exenteration or abdominoperineal resection requiring operative repair via combined open transabdominal and transperineal approach. To our knowledge, this case represents the first reported case of intestinal obstruction secondary to primary acquired perineal hernia in the absence of pelvic exenteration or abdominoperineal resection.

Metastatic squamous cell carcinoma of the anal canal is a rare presentation that is suspected in patients with risk factors such as known primary anal cancer, human papillomavirus/human immunodeficiency virus, immunosuppression, smoking, and receptive anal intercourse. Patients may present with metastasis at the index presentation of anal cancer or metastases may occur following the chemoradiation of the primary tumor. Treatment is focused on systemic therapy with chemotherapy, with the consideration of immunotherapy as second-line therapy. Predictive biomarkers may be able to personalize treatment in the future. Clinical trials of different chemotherapy and immunotherapy combinations are active to improve current management.

Deep infiltrating endometriosis (DIE) of the bowel, defined by infiltration of endometriosis into the muscularis propria, or as a lesion invading the bowel wall >5 mm depth, occurs in 5.2%–12% of women with endometriosis.1, 2 The rectum and the distal sigmoid colon are most commonly involved.3, 4 Rectal involvement may cause angulation or stricture of the bowel, causing defecatory pain and constipation.5 Cyclical inflammation of the rectal endometriosis may lead to diarrhoea, pelvic pain and rectal bleeding.5 With the advancements in minimally invasive surgery, there is an increasing trend to recommend surgery for rectal DIE. This involves rectal shaving, disc excision or segmental resection.6 There is no clear consensus as to the optimal technique for achieving symptom control and fertility in patients with DIE.7 This is in part due to varying surgical techniques particularly with heterogeneity of definitions for rectal shaving, as well as results and complications.8 There are studies advocating for a more conservative approach. In a series of 3298 patients, only 1.1% of rectal DIE cases met criteria for bowel resection.9, 10 These include major symptomatic rectal stenosis, multiple nodules infiltrating the rectosigmoid junction not amenable to serial shaving or disc excision, or extensive circumferential or posterior rectal lesions where shaving or disc excision is not feasible.11 While conservative surgery was traditionally appropriate for DIE <3 cm,12 Donnez and Roman found that shaving can be safely performed up to 6 cm in size, and the Rouen disc excision technique allowed for removal of rectal nodules >5 cm in diameter with good functional outcomes.11, 13 Shaving alone may be performed if the nodule can be easily separated from the anterior rectum to reach the cleavage plane of the rectovaginal septum, while disc excision may be preferred for mid to low rectal nodules where shaving may be technically difficult.11 They concluded that the size of the nodule should not dictate the need for rectal resection, and that the majority of DIE did not require major bowel resection. This is important, as the complication rate is significantly lower with a conservative approach: 2.2–5.7% after shaving, 9.7% after disc excision and 9.9% after segmental resection.14 However, it is advised that these techniques, particularly for larger DIE nodules be performed in centres of expertise within a multidisciplinary setting.7, 14 A meta-analysis found lower bowel perforation rate, intraoperative haemorrhage, anastomotic leak and rectovaginal fistula rate after rectal shaving compared to segmental resection.14 Disc excision was associated with lower rates of anastomotic stenosis, and that segmental resection was associated with significant risk of bowel stenosis requiring additional endoscopic or surgical intervention.14, 15 Also, the mean duration of the procedure was longer for segmental resection (151 ± 56.3 min), than for disc excision (111.5 ± 38.2 min) and shaving (96.8 ± 48.7 min).16 Donnez and Roman reported higher complication rates after rectal resection for urinary retention (0%–17.5%), anastomotic leakage (0%–4.8%) and pelvic abscesses (0%–4.2%) compared to rectal shaving.11 The rates of rectovaginal fistulas were higher after both rectal resection (0%–18.1%) and disc excision (0%–11.6%) compared to shaving (0%–2.3%).11 The risk of rectovaginal fistulas was up to 18% when rectal resection was performed for DIE close to the anal verge.17, 18 In a series of 1135 cases requiring surgery for DIE, the total stoma rate was 19.1%.19 There was no breakdown of stoma rates between the three types of surgery, however they commented that use of stoma was more frequent in facilities with higher rates of colorectal resection, suggesting that protective stoma was not commonly performed after rectal shaving.19 Quality of life (QOL) aspects of surgery is another important consideration. A prospective study involving 82 patients studied SF-36 scores (domains: pain, physical function, physical and emotional limitations, vitality, mental health, social, general health) before and after DIE surgery.20 They found that all SF-36 domains in the rectal surgery group had significantly poorer scores than patients without rectal surgery at 6–12 months after surgery except for physical function (P = 0.06) and emotional limitations (P = 0.26). Additionally, no significant differences in the SF-36 scores were found comparing rectal shave, disc excision and segmental resection 1 year after surgery.20 This was also echoed in a randomized controlled trial (RCT) where there were no differences in functional outcomes and pregnancy after 5 and 7 years between shaving or disc excision versus segmental resection.15, 21, 22 Two case series reported significant improvement in gastrointestinal QOL after rectal shaving at 1 and 3 years postoperatively.23, 24 A meta-analysis found that conservative surgery presented fewer events of constipation and diarrhoea than segmental resection.6 In addition, temporary bladder catheterisation rate after rectal shaving was reported to be 0.19%, compared to persistent urinary retention rate of 1.4%–17.5% after rectal resection likely related to bladder atony from hypogastric plexus injury.9, 23, 25, 26 There is improved sexual QOL in the rectal shaving group, compared to segmental resection.27, 28 On the other hand, while Low Anterior Resection Syndrome (LARS) questionnaires did not demonstrate a difference between rectal shaving, disc excision versus segmental resection, endometriosis confounds LARS symptoms, as patients had major and minor LARS symptoms preoperatively.27-29 There are studies that support segmental resection for DIE. These include ENDORE, a RCT assessing functional outcomes in 60 patients, which did not demonstrate differences in urinary and digestive improvements from conservative versus radical surgery.30 A meta-analysis with 1600 patients quoted a proven endometriosis recurrence rate of 2.5% in the bowel resection group, compared to 5.7% in the mixed surgical group that included rectal shaving and disc excision.31 Advocates for radical surgery argue that conservative surgery results in higher risk of recurrence in DIE. The rates of residual microscopic endometriosis was reported as high as 40% with disc excision.32-35 On the other hand, bowel resection for DIE may be associated with positive bowel margins for endometriosis up to 15%, with a risk of recurrent endometriosis symptoms.32-35 Furthermore, data on recurrence rates were based on short follow-up periods (2–4 years).31, 36 Thus, it is unclear if bowel resection provides any long-term advantage in terms of DIE recurrence. In any case, the reintervention rate was found to be <10% in three studies,9, 26, 37 so the risk of recurrence needs to be balanced with the risk of bowel resection. Interestingly, a recent RCT for rectal DIE did not demonstrate differences in recurrence rate or reoperation risk between segmental resection versus shave or disc excision after 7 years followup.22 Thus, this further supports less invasive surgery for DIE. With the increasing armamentarium of combined hormonal contraceptives (CHC), levonorgesterel-releasing intra-uterine system (LNG-IUS), Dienogest or Gonadatrophin releasing hormone (GnRH) agonists (Triptorelin or Leuprorelin) that may be used postoperatively to further reduce the risk of recurrence and persistent pain,38-41 conservative surgery may be a less risky alternative to segmental bowel resection for DIE. Bowel resection for DIE of the rectum should be reserved for major symptomatic rectal stenosis, or where it is not safe or appropriate for shaving or disc excision. Rectal resection for DIE should not be the norm, but the exception. Open access publishing facilitated by The University of Sydney, as part of the Wiley - The University of Sydney agreement via the Council of Australian University Librarians. Joseph Do Woong Choi: Data curation; formal analysis; investigation; methodology; project administration; writing – original draft; writing – review and editing. Hillary Hu: Formal analysis; investigation; validation; writing – original draft; writing – review and editing. Amy Cao: Formal analysis; supervision; validation; writing – original draft; writing – review and editing. Nimalan Pathma-Nathan: Conceptualization; formal analysis; methodology; supervision; validation; writing – review and editing. James Wei Tatt Toh: Conceptualization; formal analysis; investigation; methodology; supervision; validation; writing – review and editing.

Objective: The role of selective decontamination with oral antibiotics (OABs) and mechanical bowel preparation (MBP) prior to elective colorectal surgery is still widely debated. The objective of this study was to compare the outcomes of selective decontamination with neomycin, metronidazole and MBP compared to those of decontamination with MBP alone or with no preparation. Methods: Selective decontamination with neomycin and metronidazole combined with bowel preparation was introduced prior to elective colorectal surgery as part of an enhanced recovery after surgery program at Westmead Hospital, a major Australian tertiary referral hospital, between June 2017 and January 2023. Comparisons between short-term outcomes of OAB + MBP and MBP/no preparation were made using prospectively collected data on length of stay (LOS), readmission, mortality within 30 days, anastomotic leakage (AL), surgical site infection (SSI), urinary tract infection, deep venous thrombosis and/or pulmonary embolism, pneumonia, and ileus. Follow-up was limited to hospital stays and subsequent presentations within the health district within thirty days of surgery. The Mann-Whitney U test was used to analyse continuous data, and the chi-square test was used for categorical data. Univariate and multivariate regression modelling was performed to identify risk factors associated with an increased likelihood of SSI and AL. Results: Patients with oral neomycin and metronidazole combined with bowel preparation had reduced superficial SSI (2.7% vs. 7.6%, p = 0.043) and overall complications (32.7% vs. 44.6%, p = 0.020), particularly Clavien-Dindo 1 complications (7.3% vs. 16.5%, p = 0.009). However, the differences in AL (2.7% vs. 4.5%, p = 0.369) and organ/space SSI (1.3% vs. 3.7%, p = 0.327) were not statistically significant. The median LOS (6 d vs. 6 d, p = 0.370) was not different between the groups. Conclusion: Selective decontamination with neomycin and metronidazole reduces the risk of SSIs and overall complications. There was a trend to toward a lower AL, but this difference was not statistically significant. (c) 2024 Zhejiang University. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).

AimTo develop a priority set of quality indicators (QIs) for use by colorectal cancer (CRC) multidisciplinary teams (MDTs). MethodsThe review search strategy was executed in four databases from 2009-August 2019. Two reviewers screened abstracts/manuscripts. Candidate QIs and characteristics were extracted using a tailored abstraction tool and assessed for scientific soundness. To prioritize candidate indicators, a modified Delphi consensus process was conducted. Consensus was sought over two rounds; (1) multidisciplinary expert workshops to identify relevance to Australian CRC MDTs, and (2) an online survey to prioritize QIs by clinical importance. ResultsA total of 93 unique QIs were extracted from 118 studies and categorized into domains of care within the CRC patient pathway. Approximately half the QIs involved more than one discipline (52.7%). One-third of QIs related to surgery of primary CRC (31.2%). QIs on supportive care (6%) and neoadjuvant therapy (6%) were limited. In the Delphi Round 1, workshop participants (n = 12) assessed 93 QIs and produced consensus on retaining 49 QIs including six new QIs. In Round 2, survey participants (n = 44) rated QIs and prioritized a final 26 QIs across all domains of care and disciplines with a concordance level > 80%. Participants represented all MDT disciplines, predominantly surgical (32%), radiation (23%) and medical (20%) oncology, and nursing (18%), across six Australian states, with an even spread of experience level. ConclusionThis study identified a large number of existing CRC QIs and prioritized the most clinically relevant QIs for use by Australian MDTs to measure and monitor their performance.

Rectal cancer surgery is complex and more technically challenging than colonic surgery. Over the last 30 years internationally, there has been a growing impetus for centralizing care to improve outcomes for rectal cancer. Centralizing care may potentially reduce variations of care, increase standardization and compliance with clinical practice guidelines. However, there are barriers to implementation at a professional, political, governance and resource allocation level. Centralization may increase inequalities to accessing healthcare, particularly impacting socioeconomically disadvantaged and rural populations with difficulties to commuting longer distances to “centres of excellence”. Furthermore, it is unclear if centralization actually improves outcomes. Recent studies demonstrate that individual surgeon volume rather than hospital volume may be more important in achieving optimal outcomes. In this review, we examine the literature to assess the value of centralization for rectal cancer surgery.

Introduction: Small bowel obstruction (SBO) is common surgical pathology, most commonly secondary to adhesions. This case presents a novel cause of small bowel obstruction. Case Report: We present a case of an elderly female who presented to hospital with symptoms, signs, and radiological findings consistent with SBO. After failing non-operative management, and deteriorating clinically, decision was made for operative intervention. A laparotomy revealed a normal-appearing appendix adhering to the pelvic side wall, and consequently forming a band adhesion-like internal hernia and was the cause of the bowel obstruction. Following dissection from the pelvic wall, and appendectomy, the patient recovered and was discharged home. Histopathology demonstrated a normal appendix. Diseased appendices have rarely been described to cause bowel obstructions; however, this is the first case report describing a normal appendix causing a band-like bowel obstruction. Surgical management was necessary to establish a definitive diagnosis, and for resolution of the condition. Conclusion: This case highlights a novel cause of SBO and reiterates the heterogeneity of SBO causes. Abdominal exploration remains the gold standard diagnostic modality for intra-abdominal pathology.

Preoperative hypoalbuminemia has traditionally been used as a marker of nutritional status and is considered a significant risk factor for anastomotic leak (AL). The Westmead Enhanced Recovery After Surgery (WERAS) prospectively collected database, consisting of 361 patients who underwent colorectal surgery with primary anastomosis, was interrogated. Preoperative serum albumin and protein levels (measured within 1 week of surgery) were plotted on receiver operating characteristic curves (ROC curves) and statistically analyzed for cutoff values, sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV). The incidence of AL was 4.4

Appendiceal diverticulitis is a rare pathology which is distinctly different to acute appendicitis and associated with higher rates of morbidity and mortality. Furthermore, diagnosis is often retrospective on histopathological analysis of appendicectomy specimens due to the atypical clinical and radiological features. Herein, we present a case of ruptured appendiceal diverticulitis in a young patient with atypical clinical features and a radiologically normal appearing appendix in close proximity to an inflammatory phlegmon. This case highlights the importance of maintaining a high clinical suspicion of surgical pathology and considering atypical diagnosis in patients with inflammatory changes in the right iliac fossa.

PurposeThe management of early-stage rectal cancer in clinical practice is controversial. The aim of this network meta-analysis was to compare oncological and postoperative outcomes for T1T2N0M0 rectal cancers managed with local excision in comparison to conventional radical resection.MethodsA systematic review of Medline, Embase and Cochrane electronic databases was performed. Relevant studies were selected using PRISMA guidelines. The primary outcomes measured were 5-year local recurrence and overall survival. Secondary outcomes included rates of postoperative complication, 30-day mortality, positive margin and permanent stoma formation.ResultsThree randomized controlled trials and 27 observational studies contributed 8570 patients for analysis. Radical resection was associated with reduced 5-year local recurrence in comparison to local excision. This was statistically significant in comparison to trans-anal local excision (odds ratio (OR) 0.23; 95% confidence interval 0.16-0.30) and favourable in comparison to endoscopic techniques (OR 0.40; 95% confidence interval 0.13-1.23) although this did not reach clinical significance. Positive margin rates were lowest for radical resection. However, 30-day mortality rates, perioperative complications and permanent stoma rates all favoured local excision with no statistically significant difference between endoscopic and trans-anal techniques.ConclusionRadical resection of early rectal cancer is associated with the lowest 5-year local recurrence rates and the lowest rate of positive margins. However, this must be balanced with its higher 30-day mortality and complication rates as well as the increased risk of permanent stoma. The emerging potential role of neoadjuvant therapy prior to local resection, and the heterogeneity of its use, as an alternative treatment for early rectal cancer further complicates the treatment paradigm and adds to controversy in this field.

AbstractDuplication cysts are rare benign congenital malformations typically identified in children by the age of 2 years. We report a rare case of colonic duplication cyst with dysplasia in an adult. A 32-year-old male was diagnosed with non-specific abdominal symptoms. Abdominopelvic computed tomography scan demonstrated a submucosal cystic lesion in the right colon. He underwent laparoscopic right hemicolectomy. Histopathology showed colonic duplication cyst with low grade dysplasia. He is due for a surveillance colonoscopy in 3 years. Duplication cyst in an adult colon with dysplasia is extremely rare. They are usually present in the terminal ileum. They have non-specific abdominal symptoms or can be asymptomatic. They are often identified incidentally or intraoperatively. Imaging may demonstrate a cystic lesion. Histopathology is required for definitive diagnosis. There are no guidelines or consensus on managing duplication cysts in adults. We recommend an oncological resection of the involved colon. Surveillance with routine colonoscopy is advisable.

The initial immune response to HIV is critical in determining transmission. However, due to technical limitations we still do not have a comparative map of early mucosal transmission events. We combined RNAscope, cyclic-immunofluorescence and novel image analysis tools to quantify HIV transmission dynamics in intact human colorectal tissue. We mapped HIV enrichment to mucosal dendritic cells (DC) and submucosal macrophages, but not CD4+ T-cells, the primary targets of downstream infection. DCs appeared to funnel virus to lymphoid aggregates which acted as early sanctuaries of high viral titres whilst facilitating HIV passage to the submucosa. Finally, HIV entry induced rapid recruitment and clustering of target cells, facilitating DC and macrophage mediated HIV transfer and enhanced infection of CD4+ T-cells. These data demonstrate a rapid response to HIV structured to maximise the likelihood of mucosal infection and provide a framework for in situ studies of host pathogen interactions and immune mediated pathologies.

Background Whilst Enhanced Recovery after Surgery (ERAS) has been widely accepted in the international colorectal surgery community, there remains significant variations in ERAS programme implementations, compliance rates and best practice recommendations in international guidelines. Methods A questionnaire was distributed to colorectal surgeons from Australia and New Zealand after ethics approval. It evaluated specialist attitudes towards the effectiveness of specific ERAS interventions in improving short term outcomes after colorectal surgery. The data were analysed using a rating scale and graded response model in item response theory (IRT) on Stata MP, version 15 (StataCorp LP, College Station, TX). Results Of 300 colorectal surgeons, 95 (31.7%) participated in the survey. Of eighteen ERAS interventions, this study identified eight strategies as most effective in improving ERAS programmes alongside early oral feeding and mobilisation. These included pre-operative iron infusion for anaemic patients (IRT score = 7.82 [95% CI : 6.01–9.16]), minimally invasive surgery (IRT score = 7.77 [95% CI : 5.96–9.07]), early in-dwelling catheter removal (IRT score = 7.69 [95% CI : 5.83–9.01]), pre-operative smoking cessation (IRT score = 7.68 [95% CI : 5.49–9.18]), pre-operative counselling (IRT score = 7.44 [95% CI : 5.58–8.88]), avoiding drains in colon surgery (IRT score = 7.37 [95% CI : 5.17–8.95]), avoiding nasogastric tubes (IRT score = 7.29 [95% CI : 5.32–8.8]) and early drain removal in rectal surgery (IRT score = 5.64 [95% CI : 3.49–7.66]). Conclusions This survey has demonstrated the current attitudes of colorectal surgeons from Australia and New Zealand regarding ERAS interventions. Eight of the interventions assessed in this study including pre-operative iron infusion for anaemic patients, minimally invasive surgery, early in-dwelling catheter removal, pre-operative smoking cessation, pre-operative counselling, avoidance of drains in colon surgery, avoiding nasogastric tubes and early drain removal in rectal surgery should be considered an important part of colorectal ERAS programmes.

The initial immune response to HIV determines transmission. However, due to technical limitations we still do not have a comparative map of early mucosal transmission events. By combining RNAscope, cyclic immunofluorescence, and image analysis tools, we quantify HIV transmission signatures in intact human colorectal explants within 2 h of topical exposure. We map HIV enrichment to mucosal dendritic cells (DCs) and submucosal macrophages, but not CD4+ T cells, the primary targets of downstream infection. HIV+ DCs accumulate near and within lymphoid aggregates, which act as early sanctuaries of high viral titers while facilitating HIV passage to the submucosa. Finally, HIV entry induces recruitment and clustering of target cells, facilitating DC- and macrophage-mediated HIV transfer and enhanced infection of CD4+ T cells. These data demonstrate a rapid response to HIV structured to maximize the likelihood of mucosal infection and provide a framework for in situ studies of host-pathogen interactions and immune-mediated pathologies.

Abstract Background Intestinal neutrophil recruitment is a characteristic feature of the earliest stages of inflammatory bowel disease (IBD). Neutrophil elastase (NE) and myeloperoxidase (MPO) mediate the formation of neutrophil extracellular traps (NETs); NETs produce the bactericidal oxidant hypochlorous acid (HOCl), causing host tissue damage when unregulated. The project aim was to investigate the relationship between NET formation and clinical IBD in humans. Methods Human intestinal biopsies were collected from Crohn’s disease (CD) patients, endoscopically categorized as unaffected, transitional, or diseased, and assigned a histopathological score. Results A significant linear correlation was identified between pathological score and cell viability (TUNEL+). Immunohistochemical analysis revealed the presence of NET markers NE, MPO, and citrullinated histone (CitH3) that increased significantly with increasing histopathological score. Diseased specimens showed greater MPO+-immunostaining than control (P < .0001) and unaffected CD (P < .0001), with transitional CD specimens also showing greater staining than controls (P < .05) and unaffected CD (P < .05). Similarly, NE+-immunostaining was elevated significantly in diseased CD than controls (P < .0001) and unaffected CD (P < .0001) and was significantly higher in transitional CD than in controls (P < .0001) and unaffected CD (P < .0001). The CitH3+-immunostaining of diseased CD was significantly higher than controls (P < .05), unaffected CD (P < .0001) and transitional CD (P < .05), with transitional CD specimens showing greater staining than unaffected CD (P < .01). Multiplex immunohistochemistry with z-stacking revealed colocalization of NE, MPO, CitH3, and DAPI (cell nuclei), confirming the NET assignment. Conclusion These data indicate an association between increased NET formation and CD severity, potentially due to excessive MPO-mediated HOCl production in the extracellular domain, causing host tissue damage that exacerbates CD.

Purpose Enhanced Recovery After Surgery (ERAS) has become standard of care in colorectal surgery. However, there is not a universally accepted colorectal ERAS protocol and significant variations in care exist between institutions. The aim of this study was to examine the impact of variations in ERAS interventions and complications on length of stay (LOS). Methods This study was a single-center review of the first 200 consecutive patients recruited into our prospectively collected ERAS database. The primary outcome of this study was to examine the rate of compliance to ERAS interventions and the impact of these interventions on LOS. The secondary outcome was to assess the impact of complications (anastomotic leak, ileus, and surgical site infections) on LOS. ERAS interventions, rate of adherence, LOS, readmissions, morbidity, and mortality were recorded, and statistical analysis was performed. Results ERAS variations and complications significantly influenced patient LOS on both univariate and multivariate analysis. ERAS interventions identified as the most important strategies in reducing LOS included laparoscopic surgery, mobilization twice daily postoperative day (POD) 0 to 1, discontinuation of intravenous fluids on POD 0 to 1, upgrading to solid diet by POD 0 to 2, removal of indwelling catheter by POD 0 to 2, avoiding nasogastric tube reinsertion and removing drains early. Both major and minor complications increased LOS. Anastomotic leak and ileus were associated with the greatest increase in LOS. Conclusion Seven high-yield ERAS interventions reduced LOS. Major and minor complications increased LOS. Reducing variations in care and complications can improve outcomes following colorectal surgery.

Laparoscopic rectal surgery within the confines of a narrow pelvis may be associated with a high rate of open conversion. In the obese and morbidly obese patient, the complexity of laparoscopic surgery increases substantially. Robotic technology is known to reduce the risk of conversion, but it is unclear if it can overcome the technical challenges associated with obesity. The ACS NSQIP database was used to identify obese patients who underwent elective laparoscopic or robotic-assisted rectal resection from 2015 to 2016. Obesity was defined as a body mass index (BMI) greater than or equal to 30 kg/m2. Morbid obesity was defined as a BMI greater than or equal to 35 kg/m2. The primary outcome was unplanned conversions to open. Other outcomes measures assessed included anastomotic leak, operative time, surgical site infections, length of hospital stay, readmissions and mortality. Statistical analyses were performed using SPSS 22.0 (IBM SPSS, USA). 1490 patients had robotic-assisted and 4967 patients had laparoscopic rectal resections between 2015 and 2016. Of those patients, 561 obese patients had robotic-assisted rectal resections and 1824 patients underwent laparoscopic rectal surgery. In the obese cohort, the rate of unplanned conversion to open in the robotic group was 14% compared to 24% in the laparoscopic group (P < 0.0001). Median operative time was significantly longer in the robotic group (248 min vs. 215 min, P < 0.0001). There was no difference in anastomotic leak or systemic sepsis between the laparoscopic and robotic rectal surgery groups. In morbidly obese patients (BMI ≥ 35 kg/m2), the rate of unplanned conversion to open in the robotic group was 19% compared to 26% in the laparoscopic group (P < 0.027). There was no difference in anastomotic leak, systemic sepsis or surgical site infection rates between robotic and laparoscopic rectal resection. Multivariate analysis showed that robotic-assisted surgery was associated with fewer unplanned conversions to open (OR 0.28, P < 0.0001). Robotic-assisted surgery is associated with a decreased risk of conversion to open in obese and morbidly obese patients when compared to conventional laparoscopic surgery. However, robotic surgery was associated with longer operative time and despite improvement in the rate of conversion to open, there was no difference in complications or length of stay. Our findings are limited by the retrospective non-randomised nature of the study, demographic differences between the two groups, and the likely difference in surgeon experience between the two groups. Large randomised controlled studies are needed to further explore the role of robotic rectal surgery in obese and morbidly obese patients.