BACKGROUND:The adoption of robotic-assisted surgery (RAS) in colorectal practice is accelerating, supported by growing evidence of clinical benefit. Robotic proctors play a critical role in ensuring safe dissemination by guiding and supporting new users. However, national standards outlining their responsibilities, training and governance remain undefined. METHODS:All UK-based colorectal robotic proctors within the Association of Coloproctology of Great Britain and Ireland (ACPGBI) were invited to participate in a consensus process structured around eight predefined domains. These were informed by a prior scoping meeting. Participants received a summary report and had the opportunity to propose additional themes. A modified nominal group technique was used to generate and vote on statements. Final statements were circulated for further input post-meeting. RESULTS:Twelve of twenty invited proctors participated. A total of 32 statements were generated; 30 reached consensus and 21 were unanimously supported. Key recommendations include: (1) Robotic proctorship in the UK should encompass proctoring, preceptoring, coaching and mentoring tailored to individual surgeon needs. (2) Proctors should complete a robotic-specific 'Train the Trainers' course or equivalent. (3) Proctors must ensure the proctee can safely operate the system whilst maintaining patient safety and delivering structured feedback. (4) Industry should support communication, theatre team training and structured feedback mechanisms. (5) A distinction should be made between first- and second-generation proctors to support safe innovation in new robotic platforms. CONCLUSION:This expert consensus provides one of the first structured frameworks for robotic proctoring in colorectal surgery, aiming to improve training consistency, professional standards and patient safety.

BACKGROUND:The oncological benefits of Laparoscopic Complete Mesocolic Excision (LCME) over conventional surgery are often challenged by single-centre designs, small cohorts or short and incomplete follow-up. This study aimed to examine the difference in recurrence risk 5 years after surgery and 30-day postoperative complications before and after a population-based, multicentre LCME implementation. METHOD:LCME was implemented in the Central Denmark Region, Denmark following a training programme in 2017 for all colon cancer surgeons. Colon cancer patients from before (2015-2016, PRE-group) and after the implementation (2018-2019, POST-group) were identified through the Danish Colorectal Cancer Group Database. Recurrence 5 years after surgery was ascertained through national registers using a validated algorithm. The Aalen-Johansen estimator for competing risk was used to calculate cumulative incidence of recurrence. RESULTS:A total of 1919 patients (PRE, n = 1024; POST, n = 895) underwent curative-intended surgery in the study period. The 5-year cumulative incidence of recurrence was 16.1% (95% CI: 13.8, 18.4) in the PRE group and 12.5% (95% CI: 10.2, 14.9) in the POST group, with a significant absolute risk difference of 3.6% (95% CI: 0.3, 6.9). Furthermore, a significantly lower hazard rate of recurrence was observed in stage II patients after the LCME implementation, with a hazard rate ratio of 0.42 (95% Cl: 0.24, 0.72). Risk of severe postoperative complications was also significantly lower in the POST, compared to the PRE group. CONCLUSION:LCME implementation was associated with a significantly lower risk of recurrence and lower rate of severe postoperative complications. This study indicates that multicentre LCME implementation may improve clinical outcomes without compromising patient safety.

This study aimed to evaluate the learning curve of robotic intracorporeal single-stapling anastomosis (RiSSA) using risk-adjusted cumulative sum (RA-CUSUM) analysis based on standardized procedural intervals. We retrospectively analyzed 36 consecutive patients who underwent robotic left-sided colorectal resection with RiSSA by a single surgeon. Eight intraoperative timepoints were annotated from surgical videos to define two composite metrics: pure RiSSA interval and total purse-string suture time. RA-CUSUM analysis was applied to assess technical proficiency over time. The RA-CUSUM curve showed an inflection point at case 17 for the pure RiSSA interval and at case 11 for purse-string suture time, indicating earlier acquisition of suture skills compared to overall procedural fluency. Two Clavien–Dindo grade ≥ III complications occurred in the late phase, including one anastomotic leak (5.3

Oncologic right hemicolectomy (rHC) remains the only curative treatment for right-sided colon cancer. Despite its increasing complexity, this procedure is not centralized in many countries, underscoring the need for rigorous assessment and continuous improvement in surgical quality. Benchmarking is a validated quality improvement tool. By defining best achievable outcomes as reference (i.e. benchmarks), it enables centers to evaluate their performance and identify weaknesses or areas for improvement. This analysis aimed to establish benchmarks for outcome parameters in minimal-invasive rHC. We analyzed data from consecutive patients with adenocarcinoma of the colon who underwent minimal-invasive rHC between July 2017 and June 2022 at 19 expert centers across five continents. Ideal cases were defined as elective surgeries for cT1-T3 tumors without distant metastases, major comorbidities, or significant prior abdominal surgeries. Benchmarks were derived for 19 clinically relevant surgical outcomes, including perioperative and oncological parameters, procedure-specific complications, overall morbidity, and mortality. Benchmarks were set at the 75th percentile for negative outcomes and the 25th percentile for positive outcomes across all centers’ medians. Among 3154 patients, 686 (22%) qualified as ideal. The proportion of ideal cases varied widely across centers (range: 2 – 51%). Key benchmarks at 3 months were overall morbidity ≤38%, major (Clavien-Dindo ≥3a) complications ≤8%, and 0% mortality. Procedure-specific benchmarks were anastomotic leak ≤3%, and deep surgical site infections ≤6%. Finally, oncologic benchmarks included R0 resection rates 100% and ≥12 lymph nodes harvested ≥96.9%. Ideal compared to non-ideal patients and centers performing ≥500 cases compared to <500 cases annually demonstrated superior outcomes. This study demonstrates that, despite its complexity, minimally invasive rHC can be performed with low morbidity and high oncological accuracy. The established benchmarks provide a reference for centers striving to achieve excellence in this procedure.

The uptake of robotic-assisted colorectal surgery (RACS) across the UK and Ireland has increased exponentially over the last 5 years. It is anticipated that most ‘conventional’ laparoscopic procedures will eventually move to a robotic approach within a National Health Service that is committed to embracing robotic-assisted surgery. Working in collaboration with the surgical Royal Colleges, a more structured framework is necessary for robotic training. Inequality in robotic access and the impact that RACS is having on current colorectal surgical trainees need to be addressed, The Association of Coloproctology of Great Britain and Ireland (ACPGBI) has set out a framework to help support training in RACS at basic, advanced and trainer levels. Safer, better-trained robotic surgeons will ensure improved patient outcomes, which is the overriding goal of the ACPGBI.

BackgroundMental rehearsal (MR), the deliberate practice of skills specific to a procedure, has been successfully used in sports and music training for decades, but has not been adopted in surgery. This narrative review explores MR's role in surgical training and clinical practice, evaluating its effectiveness in motor skill acquisition, technical and non-technical skill development, and real world clinical implementation. Our aim was to assess MR's impact on both surgical education and clinical performance, while identifying the barriers to its routine adoption in surgical training.MethodsWe searched for relevant studies on the topic and impacts of MR in surgery using the Medline database up to December 2024. A range of studies were included covering mental rehearsal, surgical education, surgical training, and surgical outcomes. The primary outcomes were to provide insights into the mechanisms and implementation of MR in surgery and to assess the potential impact of MR on surgical outcomes.ResultsThe narrative review provides scientific insights into the mechanisms of MR in surgery and describes in detail the implementation methodology. The majority of evidence demonstrates that MR is beneficial when used as an adjunct approach to other forms of training. Moreover, there is evidence to support MR as a low-cost and valuable learning technique. Many questions remain regarding training schedules including the optimal duration and nature of the MR sessions, accommodating the surgeon's prior experience, optimal number of repetitions, and addressing the abilities of the participants to perform mental imagery. Most studies have heterogenous methods, diffuse aims and poor descriptions of the specific intervention components. Several studies applied MR in demanding real-life surgical environments and demonstrated feasibility in surgery.ConclusionsThe preliminary findings suggest that MR may improve the performance of operators and operating teams as an efficient adjuvant to traditional surgical skills training methods. More work is needed to better understand how MR interventions can best be implemented to improve training, practice, and outcomes in routine surgical practice.

Previous stage I-III colon cancer trials demonstrated improved peri-operative and similar long-term oncological outcomes with minimally invasive approaches compared with open surgery. Subsequent technical developments, including intracorporeal anastomosis, complete mesocolic excision (CME), refined pathologic grading systems and robotic approaches are increasingly used despite minimal supporting evidence. This international phase II trial aims to assess patient, surgical and pathological outcomes following robotic (RRHC) with laparoscopic right hemicolectomy (LRHC) for right sided colon cancer. Prospective, international multicentre pilot randomised phase II trial for patients with right colon adenocarcinoma, randomised 2:1 to robotic (RRHC) or laparoscopic (LRHC) surgery performed by accredited surgeons. Primary outcome was 90-day surgical morbidity measured using the Comprehensive Complication Index (CCI). Standardised pathology reviews, patient reported quality of life and surgeon task load index data was captured. RRHC vs. LRHC surgery allocation was 19 vs. 10, mean operative time 3.8 vs. 3.1 h with no operative mortality, all had R0 resection, CME rate 53 vs. 50

BACKGROUND:Data registries lack a definitive classification system that distinguishes different locations of colon cancer from one another. OBJECTIVE:To establish an international consensus on the definition of primary colon cancer segment locations. DESIGN:Between December 2022 and June 2023, the Delphi survey study was conducted to seek opinions from relevant international experts and eventually develop a consensus definition of each colon cancer segment. SETTING:Three-round online-based Delphi survey study. INTERVENTIONS:The online survey included 17 questions. In the first 2 rounds, participating experts were asked to rank each statement on a scale of 1 (least relevant) to 9 (most relevant). Consensus statements and definitions were revised according to the results for statements obtaining a consensus score of 7 to 9. During the third round and online meeting, definitions and statements that reached a moderate or high consensus (above 4 for more than 70% of participants) were included. MAIN OUTCOME MEASURES:The primary goal of our project was focused on precisely localizing the specific segment affected by primary colon cancer rather than identifying surgical treatment or type of resection needed for a particular segment. RESULTS:The first round included 331 experts; 301 (91%) completed the second round and 295 (98%) completed the final round. Experts strongly supported the use of a "10-cm rule" to describe colon cancer sites at the flexures and anatomical landmarks for other segments. Regarding the definition of rectosigmoid cancer, experts from United States and Europe reached a high consensus that the term rectosigmoid as a colon cancer location must be abolished in contrast to experts from Asia. The description of overlapping segments of cancers achieved a consensus of 64%. LIMITATIONS:Subjective decisions are based on individual expert clinical experience. CONCLUSIONS:This Delphi survey, the first internationally conducted consensus study, achieved a remarkable level of consensus among a panel of global experts. Ambiguity still exists regarding overlapping lesions. See Video Abstract . ESTANDARIZACIN DE LA DEFINICIN DE CADA SEGMENTO DE CNCER DE COLON CONSENSO DELPHI SOBRE LA TOMA DE DECISIONES CLNICAS PARA RESULTADOS ONCOLGICOS:ANTECEDENTES:Las bases de datos carecen de un sistema de clasificación definitivo que distinga las diferentes localizaciones del cáncer de colon.OBJETIVO:Establecer un consenso internacional sobre la definición de las localizaciones de los segmentos del cáncer de colon priamrio.DISEÑO:Entre diciembre de 2022 y junio de 2023, se realizó un estudio Delphi para recabar la opinión de expertos internacionales relevantes y, finalmente, desarrollar una definición consensuada de cada segmento del cáncer de colon.ESCENARIO:Estudio Delphi en línea de 3 rondas.INTERVENCIONES:La encuesta en línea incluyó 17 preguntas. En las dos primeras rondas, se pidió a los expertos participantes que calificaran cada afirmación en una escala del 1 al 9 (9 es la más relevante). Las afirmaciones y definiciones de consenso se revisaron según los resultados, obteniendo una puntuación de consenso de 7 a 9. Durante la tercera ronda y la reunión en línea, se incluyeron las definiciones y afirmaciones que alcanzaron un consenso moderado o alto (superior a 4 en más del 70 % de los participantes).MEDIDA PRINCIPALES DE RESULTADOS:El objetivo principal de nuestro proyecto se centró en localizar con precisión el segmento específico afectado por el cáncer de colon primario, en lugar de identificar el tratamiento quirúrgico o el tipo de resección necesario para un segmento en particular.RESULTADOS:La primera ronda incluyó a 331 expertos, 301 (91%) completaron la segunda ronda y 295 (98%) completaron la ronda final. Los expertos apoyaron firmemente el uso de una "regla de 10 cm" para describir las localizaciones del cáncer de colon en las flexuras y puntos de referencia anatómicos para otros segmentos. En cuanto a la definición de cáncer rectosigmoideo, expertos de América y Europa alcanzaron un alto consenso en la necesidad de abolir el término "rectosigmoide" como localización del cáncer de colon, a diferencia de los expertos de Asia. La descripción de los cánceres en segmentos que se superponen a alcanzó un consenso del 64%.LIMITACIONES:Las decisiones subjetivas se basan en la experiencia clínica individual de cada experto.CONCLUSIONES:Esta encuesta Delphi, el primer estudio de consenso realizado a nivel internacional, alcanzó un notable nivel de consenso entre un panel de expertos globales. Todavía existe ambigüedad en cuanto a las lesiones superpuestas. (Traducción-Dr. Jorge Silva Velazco ).

The uptake of robotic‐assisted colorectal surgery (RACS) across the UK and Ireland has increased exponentially over the last 5 years. It is anticipated that most ‘conventional’ laparoscopic procedures will eventually move to a robotic approach within a National Health Service that is committed to embracing robotic‐assisted surgery. Working in collaboration with the surgical Royal Colleges, a more structured framework is necessary for robotic training. Inequality in robotic access and the impact that RACS is having on current colorectal surgical trainees need to be addressed, The Association of Coloproctology of Great Britain and Ireland (ACPGBI) has set out a framework to help support training in RACS at basic, advanced and trainer levels. Safer, better‐trained robotic surgeons will ensure improved patient outcomes, which is the overriding goal of the ACPGBI.

Aim: Complete mesocolic excision (CME) for colon cancer has been associated with improved oncological outcomes but requires a detailed understanding of complex mesenteric vasculature. Three-dimensional (3D) reconstructed models derived from patient imaging could enhance preoperative anatomical comprehension, enabling safer, precision CME. Methods: In this two-phase, blinded, crossover study, four expert CME surgeons evaluated mesenteric vascular anatomy on CT scans and 3D models. In phase 1, surgeons assessed 66 cases, while 20 were re-evaluated in phase 2. The primary outcome measure was inter-rater reliability by Fleiss's kappa. Secondary outcomes were intra-rater reliability by Cohen's kappa and anatomical accuracy rates measured as a percentage of correct responses on a standardised questionnaire. Results: In phase 1, inter-rater agreement was higher for 3D models (average kappa 0.6, moderate agreement) than for CT scans (average kappa 0.1, poor agreement). Ileocolic vein drainage and ileocolic artery trajectory showed the highest kappa values with 3D imaging (0.85 and 0.93, respectively). Accuracy was also superior with 3D across all surgeons (mean 89.7% correct) versus CT (mean 79.1% correct, P < 0.001). In phase 2, intra-rater reliability remained higher for 3D (average Cohen's kappa 0.61) than CT scans (Cohen's kappa 0.27). Conclusion: 3D mesenteric models significantly improve inter- and intra-rater reliability among CME experts over traditional CT scans while markedly enhancing anatomical comprehension accuracy about critical right-sided colonic vasculature. 3D planning could facilitate CME by enabling superior preoperative visualisation of these vessels.

Robotic intracorporeal single-stapled anastomosis (RiSSA) is an innovative technique in robotic low anterior resection with total mesorectal excision (LAR-TME), though its outcomes remain underreported, particularly among Asian rectal cancer patients. This study retrospectively evaluated early clinical outcomes of RiSSA in robotic LAR-TME performed at a tertiary medical center in Kaohsiung, Taiwan. A total of 22 rectal cancer patients undergoing robotic LAR-TME with RiSSA between May 2023 and September 2024 were reviewed. Demographic and tumor-related factors such as age, gender, BMI, tumor size, and location were analyzed, along with key surgical and postoperative outcomes including blood loss, operative time, complications, mortality, length of hospital stay, ICU admissions, readmissions, and reoperations. The median patient age was 60.4 years. 72.7% of the patients were male. Median BMI and tumor size were 23.0 kg/m² and 3.6 cm, respectively. 68.2% of the tumors were in the mid or lower rectum. The median console time was 186.5 minutes. The median intraoperative estimated blood loss was 40 mL. No mortality or anastomotic leakage occurred. The median hospital stay was 7 days, with only three minor complications (Clavien-Dindo I-II) reported, including wound infections and chyle leakage. No unplanned ICU admissions, readmissions, or reoperations occurred. These findings suggest that RiSSA during robotic LAR-TME is a safe and feasible alternative to conventional double-stapled anastomosis methods, demonstrating favorable short-term outcomes with minimal complications. Further large-scale studies are warranted to validate its long-term safety and clinical effectiveness.

Restorative proctocolectomy (RPC) and total colectomy with ileorectal anastomosis (TC-IRA) are traditional surgical options for individuals with familial adenomatous polyposis (FAP). Re-appraisal and modification to these techniques, such as near-total colectomy with ileo-distal sigmoid anastomosis (NT-IDSA) and RPC with robotic intracorporeal single-stapled anastomosis (RPC-RiSSA), have been implemented in recent years. This study aimed to evaluate the early postoperative outcomes associated with novel techniques employed in a single centre for restorative surgery in patients with FAP. A retrospective analysis was conducted using data from patients with FAP who underwent prophylactic restorative surgery between January 2008 and December 2022 at St Mark’s Hospital. Two hundred fifty-three individuals underwent restorative surgery over the 15-year period; 102/253 (40.3

The applications of computer-generated modelling in surgery are increasing and diverse. Surgeons utilise these models for preoperative planning and intraoperative guidance. In this chapter, techniques for 3D reconstruction, including volume rendering, surface rendering, and voxel-based methods are described. We are discussing advantages and limitations of these techniques, and its impact on surgical and procedure planning. The models may improve surgical accuracy and efficiency, reduce intraoperative risks and ultimately improve patient outcomes. In complex procedures, such as craniofacial surgery or organ transplantation, 3D models provide unprecedented detail, aiding surgeons in navigating critical structures. We will also discuss the role of computer-generated models in surgical simulation and training. These models offer a safe and effective environment for surgeons to hone their skills and practice intricate procedures without risk to patients.

BACKGROUND: Surgical management of splenic flexure carcinoma remains controversial. OBJECTIVE: This study aimed to establish an expert international consensus on splenic flexure carcinoma management. DESIGN: A 3-round online-based Delphi study was conducted between September 2020 and April 2021. SETTING: The first round included 18 experts from 12 different countries. For the second and third rounds, each expert in the first round was asked to invite 2 more colorectal surgeons (n = 47). Out of 47 invited experts, 89% (n = 42) participated in the second and third rounds of the consensus. INTERVENTIONS: A total of 35 questions were created and sent via the online questionnaire tool. MAIN OUTCOME MEASURES: Levels of recommendation based on voting concordance were graded as follows: more than 75% agreement was defined as strong, between 50% and 75% as moderate, and below 50% as weak. RESULTS: There was moderate consensus on the definition of splenic flexure (55%) as 10 cm from either side where the distal transverse colon turns into the proximal descending colon. Also, experts recommended an abdominopelvic CT scan plus intraoperative exploration (moderate consensus, 72%) for tumor localization and cancer registry. Segmental colectomy was the preferred technique for the management of splenic flexure carcinoma in the elective setting (72%). Moderate consensus was achieved on the technique of complete mesocolic excision and central vascular ligation principles for splenic flexure carcinoma (74%). Only strong consensus was achieved on the surgical approach for minimally invasive surgery (88%). LIMITATIONS: Subjective decisions are based on individual expert clinical experience and not evidence based. CONCLUSIONS: This is the first internationally conducted Delphi consensus study regarding splenic flexure carcinoma. The definition of splenic flexure remains ambiguous. To more effectively compare oncologic outcomes among different cancer registries, guidelines need to be developed to standardize each domain and avoid arbitrary definitions. See Video Abstract at http://links.lww.com/DCR/C143. ESTANDARIZACIÓN DE LA DEFINICIÓN Y MANEJO QUIRÚRGICO DEL CARCINOMA DE ÁNGULO ESPLÉNICO ESTABLECIDO POR UN CONSENSO INTERNACIONAL DE EXPERTOS UTILIZANDO LA TÉCNICA DELPHI: ¿ESPACIO PARA MEJORAR? ANTECEDENTES: El tratamiento quirúrgico del cáncer de ángulo esplénico sigue siendo controvertido. OBJETIVO: Establecer un consenso internacional de expertos sobre el manejo del cáncer del ángulo esplénico. DISEÑO: Se condujo un estudio Delphi en línea de 3 rondas entre septiembre de 2020 y febrero de 2021. ESCENARIO: La primera ronda incluyó a 18 expertos de 12 países distintos. Para la segunda y tercera rondas, a cada experto de la primera ronda se le pidió que invitara a 2 cirujanos colorrectales más de su región (n = 47). De los 47 expertos invitados, el 89% (n = 42) participó en la segunda y tercera ronda del consenso. INTERVENCIONES: Se crearon y enviaron un total de 35 preguntas a través de la herramienta de cuestionario en línea. PRINCIPALES MEDIDAS DE RESULTADO: Los niveles de recomendación basados en la concordancia de votos fueron jerarquizados de la siguiente manera: más del 75% de acuerdo se definió como fuerte, entre 50 y 75% como moderado y por debajo del 50% como débil. RESULTADOS: Hubo un consenso moderado sobre la definición de ángulo esplénico (55%) como 10 cm desde cualquier lado donde el colon transverso distal se convierte en el colon descendente proximal. Así también, los expertos recomendaron la tomografía computarizada abdominopélvica más la exploración intraoperatoria (consenso moderado, 72%) para la localización del tumor y el registro del ángulo esplénico. La colectomía segmentaria fue la técnica preferida para el tratamiento del cáncer de ángulo esplénico en el caso de ser electivo (72%). Se logró un consenso moderado sobre la técnica de escisión completa del mesocolon y los principios de ligadura vascular a nivel central para el cáncer de ángulo esplénico (74%). Solo se logró un fuerte consenso sobre el abordaje quirúrgico para la cirugía mínimamente invasiva (88%). LIMITACIONES: Decisiones subjetivas basadas en la experiencia clínica de expertos individuales y no basadas en evidencia. CONCLUSIONES: Este es el primer estudio internacional de consenso Delphi realizado sobre el cáncer de ángulo esplénico. Si bien encontramos un consenso moderado sobre las modalidades de diagnóstico preoperatorio y el manejo quirúrgico, la definición de ángulo esplénico sigue siendo ambigua. Para comparar de manera más efectiva los resultados oncológicos entre diferentes registros de cáncer, se deben desarrollar pautas para estandarizar cada dominio y evitar definiciones arbitrarias. Consulte Video Resumen en http://links.lww.com/DCR/C143. (Traducción—Dr. Osvaldo Gauto )

AimRight hemicolectomy with complete mesocolic excision (CME) requires the removal of an intact mesocolic envelope. The study aimed to determine, on the basis of macroscopic and microscopic anatomical studies, the optimal surgical dissection planes for CME to preserve fascial integrity. Unequivocal anatomical nomenclature was applied to describe the retrocolic fascial system and compared to frequently used eponyms (Toldt, Gerota, Fredet, Treitz). MethodStepwise macroscopic dissections, cross-section studies and histological analysis were performed on body donors to identify the components of the retrocolic fascial system. Based on these anatomical findings, the optimal surgical dissection planes for CME were validated in laparoscopic training courses on body donors and in robot-assisted surgical procedures in patients. ResultsThe mesocolic tissue and lymphovascular pedicles were enveloped by the ventral and dorsal mesocolic leaf (mesocolic fascia). The mesocolic fascia was attached to the parietal peritoneal fascia ('fascia of Toldt') along the parieto-mesocolic interface, and further cranially to the pre-duodenopancreatic fascia along the mesocolic-duodenopancreatic interface ('space of Fredet'). Dorsally, the parietal peritoneal fascia was separated from the anterior renal fascia ('fascia of Gerota') by the parieto-renal interface. Dissection along this interface in front of the anterior renal fascia followed by incision of the parietal peritoneal fascia at the duodenal border and opening the mesocolic-duodenopancreatic interface yielded the best macroscopic appearance of specimens and was considered optimal for CME. ConclusionThe retrocolic fascial system as well as the surgical dissection planes for CME can be described by clearly defined anatomical terms rather than potentially confusing eponyms.

Aim: The complete mesocolic excision competency assessment tool (CMECAT) is a novel tool designed to assess technical skills in minimally invasive complete mesocolic excision (CME) surgery. The aim of this study was to assess construct validity and reliability of CMECAT in a clinical context.Method: Colorectal surgeons were asked to submit video recorded laparoscopic CME resections for independent assessment of their technical abilities. The videos were grouped by surgeons' training level, and four established CME experts were recruited as CMECAT assessors. Extended reliability analysis (G-theory) was applied to describe assessor agreement.Results: A total of 19 videos and 72 assessments were included in the analysis. Overall, technical skills assessed by CMECAT improved with increased training level: the experts scored significantly better than the untrained surgeons (3.3 vs. 2.5 points; p < 0.01). On right-sided resections, significantly higher scores were reported with increased training level for all categories and sections, while for left-sided resections, the variance across groups was smaller and significantly higher scores were only reported for oncological safety describing items. Overall, assessor agreement was high (G-coefficient: 0.81).Conclusion: This study confirms that CMECAT can be applied to video recorded CME cases for technical skill assessment. Further, it can reliably assess technical performance in right sided CME surgery, where construct validity has now been established. More videos are required to evaluate its validity on left colonic CME. In the future, we hope CMECAT can improve feedback during CME training, serve as a tool in certification processes and contribute to distinguishing CME from conventional surgery in future research.