Challenges and considerations of robotic colorectal surgery in obesity: a clinical practice review

Introduction

Background

Obesity is a growing epidemic and affects more than 890 million (13%) adults globally. In some countries such as Australia, two in three adults were overweight or obese based on 2022 report (1,2). The prevalence of obesity has nearly tripled since 1975 and is projected to increase to 1.02 billion adults (18%) globally by 2030 (3).

Obesity has been linked to higher incidences of colorectal malignancy and development of complications of benign colorectal conditions such as colonic diverticula disease (4,5). As a result, there is an increasing population of patients with obesity who require colorectal surgical interventions.

Surgery in the setting of obesity presents its unique set of challenges such as significant visceral adiposity, difficult access to operative field (6), and increased rate of morbidity and complications, including conversion to laparotomy (7). It is well documented that obesity is a risk factor for post-operative wound infections (8-12).

The conventional laparoscopic platform has been the cornerstone of minimally invasive surgery for decades, primarily because it offers improved surgical outcomes compared to open procedures. While its application in patients with obesity has been extensively studied, the platform still presents technical limitations such as two-dimensional view, limited degree of freedom at the instrument tips, fulcrum effect, and inadequate access to tight anatomical spaces such as the pelvis. All these are further exacerbated by increased visceral adiposity.

The advent of the robotic surgical platform revolutionised minimally invasive surgery. It offers superior visualisation and advanced instrument articulation, enabling enhanced depth perception, improved identification of anatomical structures, and precise tissue manipulation. Although these technical advantages can help address the challenges associated with colorectal surgery in obesity, the application of the robotic platform requires specialised skillset and comes with its own set of distinct challenges.

Rationale and knowledge gap

Although the robotic surgical platform theoretically addresses several limitations inherent to conventional laparoscopic techniques—particularly in obese patients—it is imperative to undertake a thorough review of the existing literature. Furthermore, careful consideration must be given to the procedural heuristics and technical nuances of robotic colorectal surgery, many of which are insufficiently detailed or absent from current academic discourse.

Objective

To review the existing literature assessing the safety and advantages of the robotic platform in colorectal surgery, with particular focus on the obese population. This review aims to identify the principal clinical challenges in the obese patients and how to minimise them, to describe key manoeuvres to assist the robotic colorectal surgeon optimise operating conditions preoperatively and intraoperatively, and to identify and describe complications that may arise in this population of patients.

Robotic colorectal surgery in patients with obesity

Safety profile and challenges in the obese cohort

Robotic platforms are rapidly becoming a ubiquitous tool in colorectal surgery. Robotic surgery confers certain advantages for both the obese patients and the operating surgeon.

Technical challenges in robotic surgery in the obese patients are related not only to the abdominal adiposity, but the anatomic changes to the pelvic viscera and their mesentery. Vessel visualisation, skeletonization, and ligation prove challenging in a thick, bulky mesentery. Restricted views and access can be further constrained in patients with a narrow pelvis and excess adiposity in the pelvis (13).

Obesity has been identified as an independent factor associated with increased operative difficulty in robotic colorectal surgery. Yuval et al. noted higher body mass index (BMI) as a predictor of a longer operation in low anterior resection (LAR) cases for rectal cancers, a surrogate marker for operative difficulty in their study (14). Rates of other surrogate markers for operative difficulty, such as conversion to laparotomy, are higher in obese patients undergoing robotic colorectal surgery (7). Interestingly, a meta-analysis by Wee et al. also noted the overall higher conversion to open rate in the obese population, however when compared with laparoscopic surgery, robotic surgery conversion rates were lower in the obese patient population (12). Other studies have also demonstrated lower rates of conversion to laparotomy in obese patients with robotic colorectal surgery compared to laparoscopic colorectal surgery (15,16). Whilst the landmark ROLARR trial showed overall robotic-assisted surgery did not reduce rates of conversion to laparotomy, a subgroup analysis of male, obese patients showed lower rates of conversion to open surgery with a robotic approach (17).

Numerous studies have suggested the robotic approach to be non-inferior to traditional laparoscopic techniques (6,10,11,18). A multisite retrospective study by Curfman et al. [2023] showed no difference in lymph node yield in obese patients when comparing the robotic and laparoscopic approaches (19). Interestingly, this study did show that increased BMI had a significant influence on reducing the lymph node yield, regardless of the surgical approach. These sentiments were echoed by various studies which also saw comparable lymph node harvest rates and clear circumferential resection margin (CRM) (14,17).

Multiple studies demonstrate comparable outcomes between the robotic and laparoscopic approaches in the obese population such as surgical site infection, anastomotic leak, and reoperation rates, some studies report earlier recovery, shorter length of stay, and decreased readmission rates following robotic colorectal surgery (10,12,20,21). Importantly, the quality of the oncological resection in terms of lymph node yield and CRM also do not appear to be compromised using the robotic modality as mentioned earlier.

Pelvic dissection with a robotic platform may lead to a reduction in sexual and bladder dysfunction compared with the laparoscopic approach (22). A study of 137 patients who completed pre- and post-operative functional questionnaires and showed a significant improvement in those who underwent robotic surgery, implying improved autonomic nerve preservation. Two meta-analyses comparing robotic rectal cancer surgery with a laparoscopic approach have suggested improved male urinary and sexual function post-robotic surgery (23,24). The same studies have not been documented in the obese-specific patients and further studies are required to assess whether the platform has the same benefit in this population.

It would be an oversight not to mention the benefits of robotic surgery in obese patients on the ergonomics of the primary surgeon. Dixon et al. [2024] demonstrated in their randomised-controlled trial, that ergonomic risk scores and cognitive strain were reduced using an open-console robotic system when compared to laparoscopic surgery (25). Other studies have similarly reported reduced physical workload when using a robotic surgical platform compared to a laparoscopic platform (26-28). One of the most applicable studies was by Law et al. who investigated potential improvements in robotic colorectal surgery demonstrated lower physical workload on the robotic platform. Although the median BMI of patients in their study was 27 kg/m², patient BMI was associated with increased surgical workload albeit a weak one (r=0.29) (29). Therefore, it may be postulated that the robotic platform attenuates the physical strain associated with increased torque at transabdominal ports, force transmission through instrument tips during retraction, and the demands of complex surgical manoeuvres.

Technical considerations in robotic colorectal surgery in the obese patient

General considerations

Patients with a high BMI are accompanied with both intraperitoneal and subcutaneous adiposity contributing to the thick, large abdominal wall which can cause difficulties manipulating laparoscopic instruments due to the torque required to facilitate manoevering the tips of the instruments (30). Occasionally, the laparoscopic instruments may not be able to provide the necessary torque to complete the surgery, requiring conversion to open (30). Articulated instruments and increased rotational capabilities of the robotic platforms make working in narrow and deep crevices such as the pelvis, easier to navigate and less challenging to operate in (6,11). Nevertheless, some technical considerations may be of use in this specific population.

Retraction and exposure—don’t overlook the humble gauze

Exposure and identification of vascular pedicles is one major challenge in the obese patient. The often shortened and bulky mesentery creates difficulties not only in identification, but in maintaining appropriate visual exposure.

Standard gauze can often assist in aiding visualisation by maintaining retraction of the small intestine, allowing continuous exposure of the pedicle. This can be useful for ileocolic vessel isolation or similarly inferior mesenteric artery (IMA) isolation (31).

Intracorporeal anastomosis (ICA)

A significant advantage of the robotic platform is the capacity to provide the surgeon the ability to perform the manoeuvres which mirror natural wrist and hand movements. This is particularly apparent in intracorporeal suturing, one of the main advantages using the robotic platform. The robotic arms provide articulating instruments and measured rotational movements which are limited in the laparoscopic platforms.

ICA avoids the need to consider mesenteric length and additional mobilisation that is required for an extracorporeal anastomosis (ECA). The specimen must traverse not only the large abdominal cavity, but the extent of dissection must allow for ease of exteriorisation and creation of a tension free anastomosis.

There are no studies to date that directly compare ICA and ECA in the obese patient population using the robotic platform. However, van Oostendorp performed a systematic review focusing on ICA versus ECA using the laparoscopic approach which suggested that the reduction in morbidity demonstrated using the ICA technique appears to be primarily “related to the extraction site” (32). The authors found that the extraction site in the ICA population group was significantly shorter, the rate of surgical site infections was lower, morbidity associated with respiratory complications lower, hernia rates lower, and overall less pain associated with ICA. The benefits, in part, may be due to the ability to perform a Pfannenstiel incision as the extraction site.

Echoing these sentiments, a multicenter prospective trial performed by Cleary et al. [2022] also reported on a significantly shorter extraction site incision length when performing an ICA using the robotic approach, which is of particular significance in the obese population (33). Moreover, Widmar et al. demonstrated a significant reduction in the rate of incisional hernia when comparing robotic ICA with robotic ECA (34).

Consideration of natural orifice surgical extraction (NOSE)

ICA also allows for the consideration of alternative specimen extraction sites. NOSE, through either a transvaginal or transrectal approach, avoids the need to make an additional incision in the abdominal wall. With the increased rates of wound-related complications in obese patients, NOSE offers an alternative approach in obese patients that may improve outcomes. Using a NOSE and ICA technique may overcome some obesity related challenges in surgery for diverticulitis, without significant difference between operative times, post-operative ileus, and surgical site infections between obese and non-obese counterparts (35). Obese patients had similar overall complication rates and rates of anastomotic leak compared with non-obese patients, but longer operating times when NOSE was used in colectomies for benign conditions, suggesting it is a safe and viable approach in those with an increased BMI (36).

A small, retrospective Australian study has suggested that not only is NOSE feasible in the obese population undergoing colorectal surgery, but they may also benefit from favourable short-term outcomes such as reduced hospital stay and lower morbidity (37).

Ureteric indocyanine green (ICG)

Ureteric identification can be particularly challenging in obese patients (38,39). Marked retroperitoneal adiposity may displace the ureters more medially than expected (39). The use of ICG as an adjunct in robotic surgery in the obese population has marked benefit in identifying the ureters in a patient with increased intraabdominal and retroperitoneal adiposity (39). The ease of which, is as simple as a push of a button to utilise the integrated Firefly mode. Whilst this technology is available in the laparoscopic platform, the near-infrared fluorescent imaging capability is one that is only available using specialised integrated camera systems. A study by White et al. [2021] demonstrated the safety and practicality of intraureteral ICG administration with the use of a ureteral catheter through the ureteral orifice (40). This technique facilitated the visualisation of the ureters with the median visualisation time of 8 hours (40). Later, a systematic review by Garoufalia and Wexner [2022] concluded that this technique was “safe and effective” after analysing the outcomes of 142 patients, 70% of which underwent robotic surgery (41).

Conclusions

Technical challenges are exaggerated in the obese patient cohort, both from an anatomical perspective and a physiological standpoint. The robotic platform offers fine, precise movements, superior visualisation, and ergonomic benefits that are ideal to utilise in the technically demanding patient. Robotic-assisted approaches offer several advantages over conventional laparoscopic colorectal surgery in obese patients. Robotic-assisted colorectal surgery produces improved urinary and sexual function in males post-operatively. The robotic platform allows for improved ease in performing maneuvers such as ICA and NOSE, techniques which appear to overcome some obesity-related challenges in laparoscopic surgery. The use of ICG as an adjunct to robotic surgery may assist in the more challenging ureteric identification in obese patients, particularly when adiposity can distort the anatomy. Taken together, robotic-assisted platforms in colorectal surgery allow easier facilitation of the above techniques in obese patients, which can all reduce complication rates. Furthermore, robotic-assisted platforms reduce cognitive and ergonomic strain encountered by colorectal surgeons when operating on obese patients.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the Guest Editors (Zi Qin Ng and Zhen Hao Ang) for the series “Robotic Colorectal Surgery” published in AME Surgical Journal. The article has undergone external peer review.

Peer Review File: Available at https://asj.amegroups.com/article/view/10.21037/asj-25-26/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://asj.amegroups.com/article/view/10.21037/asj-25-26/coif). The series “Robotic Colorectal Surgery” was commissioned by the editorial office without any funding or sponsorship. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. World Health Organization. Obesity and overweight. 2025. Available online: https://www.who.int/en/news- room/fact-sheets/detail/obesity-and-overweight
2. Australian Institute of Health and Welfare. Overweight and obesity. 2024. Available online: https://www.aihw.gov.au/reports/overweight-obesity/overweight-and-obesity/contents/about
3. Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19·2 million participants. Lancet 2016;387:1377-96. [Crossref] [PubMed]
4. Kumar R, Brown A, Okano S, et al. Overweight and obesity are associated with colorectal neoplasia in an Australian outpatient population. Sci Rep 2024;14:23501. [Crossref] [PubMed]
5. Bistre-Varon J, Gunter R, Del Rio RS, et al. Is the NICE procedure the great equalizer for patients with high BMI undergoing resection for diverticulitis? Surg Endosc 2024;38:7518-24. [Crossref] [PubMed]
6. Panteleimonitis S, Pickering O, Abbas H, et al. Robotic rectal cancer surgery in obese patients may lead to better short-term outcomes when compared to laparoscopy: a comparative propensity scored match study. Int J Colorectal Dis 2018;33:1079-86. [Crossref] [PubMed]
7. Suwa Y, Joshi M, Poynter L, et al. Obese patients and robotic colorectal surgery: systematic review and meta-analysis. BJS Open 2020;4:1042-53. [Crossref]
8. Duchalais E, Machairas N, Kelley SR, et al. Does obesity impact postoperative outcomes following robotic-assisted surgery for rectal cancer? Surg Endosc 2018;32:4886-92. [Crossref] [PubMed]
9. Li Y, Deng JJ, Jiang J. Relationship between body mass index and short-term postoperative prognosis in patients undergoing colorectal cancer surgery. World J Clin Cases 2023;11:2766-79. [Crossref] [PubMed]
10. Harr JN, Haskins IN, Amdur RL, et al. The effect of obesity on laparoscopic and robotic-assisted colorectal surgery outcomes: an ACS-NSQIP database analysis. J Robot Surg 2018;12:317-23. [Crossref] [PubMed]
11. Hannan E, Troy A, Feeney G, et al. The impact of body mass index on outcomes in robotic colorectal surgery: a single-centre experience. J Robot Surg 2022;16:279-85. [Crossref] [PubMed]
12. Wee IJY, Kuo LJ, Ngu JC. The impact of robotic colorectal surgery in obese patients: a systematic review, meta-analysis, and meta-regression. Surg Endosc 2019;33:3558-66. [Crossref] [PubMed]
13. Bell SW, Warrier SK. Optimization of bodyweight before visceral surgery in obese patients. Br J Surg 2017;104:646-7. [Crossref] [PubMed]
14. Yuval JB, Thompson HM, Fiasconaro M, et al. Predictors of operative difficulty in robotic low anterior resection for rectal cancer. Colorectal Dis 2022;24:1318-24. [Crossref] [PubMed]
15. Abd El Aziz MA, Grass F, Perry W, et al. Colectomy for patients with super obesity: current practice and surgical morbidity in the United States. Surg Obes Relat Dis 2020;16:1764-9. [Crossref] [PubMed]
16. McKechnie T, Khamar J, Chu C, et al. Robotic versus laparoscopic colorectal surgery for patients with obesity: an updated systematic review and meta-analysis. ANZ J Surg 2025;95:675-89. [Crossref] [PubMed]
17. Jayne D, Pigazzi A, Marshall H, et al. Effect of Robotic-Assisted vs Conventional Laparoscopic Surgery on Risk of Conversion to Open Laparotomy Among Patients Undergoing Resection for Rectal Cancer: The ROLARR Randomized Clinical Trial. JAMA 2017;318:1569-80. [Crossref] [PubMed]
18. Cheng CL, Rezac C. The role of robotics in colorectal surgery. BMJ 2018;360:j5304. [Crossref] [PubMed]
19. Curfman KR, Gowing JM, Lesnick RM, et al. Comparison of robotic versus laparoscopic right colectomy node retrieval in the obese population. J Robot Surg 2023;17:1349-55. [Crossref] [PubMed]
20. Zhao S, Li R, Zhou J, et al. Comparative analysis of robotic and laparoscopic surgery for mid and low rectal cancer in patients with varied body mass indexes: evaluating of short-term outcomes. J Robot Surg 2024;18:67. [Crossref] [PubMed]
21. Chen ZL, Du QL, Zhu YB, et al. A systematic review and meta-analysis of short-term outcomes comparing the efficacy of robotic versus laparoscopic colorectal surgery in obese patients. J Robot Surg 2024;18:167. [Crossref] [PubMed]
22. Wang G, Wang Z, Jiang Z, et al. Male urinary and sexual function after robotic pelvic autonomic nerve-preserving surgery for rectal cancer. Int J Med Robot 2017; [Crossref] [PubMed]
23. Fleming CA, Cullinane C, Lynch N, et al. Urogenital function following robotic and laparoscopic rectal cancer surgery: meta-analysis. Br J Surg 2021;108:128-37. [Crossref] [PubMed]
24. Flynn J, Larach JT, Kong JCH, et al. Patient-Related Functional Outcomes After Robotic-Assisted Rectal Surgery Compared With a Laparoscopic Approach: A Systematic Review and Meta-analysis. Dis Colon Rectum 2022;65:1191-204. [Crossref] [PubMed]
25. Dixon F, Vitish-Sharma P, Khanna A, et al. Robotic assisted surgery reduces ergonomic risk during minimally invasive colorectal resection: the VOLCANO randomised controlled trial. Langenbecks Arch Surg 2024;409:142. [Crossref] [PubMed]
26. Dalager T, Jensen PT, Eriksen JR, et al. Surgeons’ posture and muscle strain during laparoscopic and robotic surgery. Br J Surg 2020;107:756-66. [Crossref] [PubMed]
27. Hubert N, Gilles M, Desbrosses K, et al. Ergonomic assessment of the surgeon’s physical workload during standard and robotic assisted laparoscopic procedures. Int J Med Robot 2013;9:142-7. [Crossref] [PubMed]
28. Park LS, Pan F, Steffens D, et al. Are Surgeons Working Smarter or Harder? A Systematic Review Comparing the Physical and Mental Demands of Robotic and Laparoscopic or Open Surgery. World J Surg 2021;45:2066-80. [Crossref] [PubMed]
29. Law KE, Lowndes BR, Kelley SR, et al. NASA-Task Load Index Differentiates Surgical Approach: Opportunities for Improvement in Colon and Rectal Surgery. Ann Surg 2020;271:906-12. [Crossref] [PubMed]
30. Robinson SP, Hirtle M, Imbrie JZ, et al. The mechanics underlying laparoscopic intra-abdominal surgery for obese patients. J Laparoendosc Adv Surg Tech A 1998;8:11-8. [Crossref] [PubMed]
31. Sylla P, Kaiser AM, Popowich D. editors. The SAGES manual of colorectal surgery. Cham: Springer International Publishing; 2020.
32. van Oostendorp S, Elfrink A, Borstlap W, et al. Intracorporeal versus extracorporeal anastomosis in right hemicolectomy: a systematic review and meta-analysis. Surg Endosc 2017;31:64-77. [Crossref] [PubMed]
33. Cleary RK, Silviera M, Reidy TJ, et al. Intracorporeal and extracorporeal anastomosis for robotic-assisted and laparoscopic right colectomy: short-term outcomes of a multi-center prospective trial. Surg Endosc 2022;36:4349-58. [Crossref] [PubMed]
34. Widmar M, Aggarwal P, Keskin M, et al. Intracorporeal Anastomoses in Minimally Invasive Right Colectomies Are Associated With Fewer Incisional Hernias and Shorter Length of Stay. Dis Colon Rectum 2020;63:685-92. [Crossref] [PubMed]
35. Haas EM, Secchi Del Rio R, Reif de Paula T, et al. The robotic NICE procedure outperforms conventional laparoscopic extracorporeal-assisted colorectal resection: results of a matched cohort analysis. Surg Endosc 2024;38:390-9. [Crossref] [PubMed]
36. Chen MZ, Cartmill J, Gilmore A. Natural orifice specimen extraction for colorectal surgery: Early adoption in a Western population. Colorectal Dis 2021;23:937-43. [Crossref] [PubMed]
37. Lendzion RJ, Gilmore AJ. Laparoscopic right hemicolectomy with intracorporeal anastomosis and natural orifice surgery extraction/minimal extraction site surgery in the obese. ANZ J Surg 2021;91:1180-4. [Crossref] [PubMed]
38. Marcelissen TA, Den Hollander PP, Tuytten TR, et al. Incidence of Iatrogenic Ureteral Injury During Open and Laparoscopic Colorectal Surgery: A Single Center Experience and Review of the Literature. Surg Laparosc Endosc Percutan Tech 2016;26:513-5. [Crossref] [PubMed]
39. Khalafi S, Botero Fonnegra C, Reyes A, et al. Developments in the Use of Indocyanine Green (ICG) Fluorescence in Colorectal Surgery. J Clin Med 2024;13:4003. [Crossref] [PubMed]
40. White LA, Joseph JP, Yang DY, et al. Intraureteral indocyanine green augments ureteral identification and avoidance during complex robotic-assisted colorectal surgery. Colorectal Dis 2021;23:718-23. [Crossref] [PubMed]
41. Garoufalia Z, Wexner SD. Ureter identification utilizing indocyanine green (ICG) imaging in colorectal surgery: a systematic review of the literature. Mini-Invasive Surgery 2022;6:51. [Crossref]