Mathis, Kellie L.

Objective: To determine if a Super Learner (SL) machine learning approach could improve the predictive accuracy of the American College of Surgeons Risk Calculator (ACS-RC) for postoperative complications in patients undergoing colorectal surgery. Summary of Background Data: Machine learning (ML) has shown significant potential to advance medical fields, including surgical risk prediction. Current tools, like the ACS-RC which uses logistic regression and extreme gradient boosting, are standard but may be enhanced by more advanced ML ensembles. Methods: This retrospective study analyzed colorectal surgery cases from the 2018-2022 ACS National Surgical Quality Improvement Program (NSQIP) database. An SL model, which combines multiple ML algorithms, was developed to predict fourteen postoperative outcomes. Its performance was compared against traditional logistic regression (LOG) and extreme gradient boosting (XGB) models. Key performance metrics included discrimination (AUROC, AUPRC) and calibration (Brier score, Hosmer-Lemeshow test). Results: The SL model demonstrated superior performance across all predicted complications when compared to both LOG and XGB. It showed superior discrimination for severe outcomes, achieving an AUROC greater than 0.94 for predicting mortality. The SL model was also more accurate in predicting infectious complications and length of stay, and its calibration metrics indicated a better overall fit and accuracy. Conclusions: The Super Learner model enhances the accuracy of postoperative risk prediction in colorectal surgery. Its superior performance suggests it is a promising tool for improving personalized patient counseling, aiding clinical decision-making, and optimizing resource allocation.

Background and Objectives: Perineal wound complications and pelvic fluid collections or abscesses following proctectomy for Crohn’s disease are a common cause of morbidity and might be mitigated by filling the pelvis and occluding the pelvic inlet with a flap. Alternative flap options can be considered when inadequate omentum is available and when avoiding myofasciocutaneous flaps. Materials and Methods: A retrospective review of our Crohn’s proctectomy database was conducted to identify patients who underwent a non-omental or non-myofasciocutaneous local pedicle flap to their pelvis or pelvic exclusion using biological material during surgery. The techniques and outcomes of these alternative techniques are described in detail. Results: 228 patients underwent proctectomy for Crohn’s disease during the 10-year study period. However, only six patients had their pelvis filled or pelvic inlet occluded using a non-omental, non-myofasciocutaneous local pedicled flap or biological material. The techniques identified included two sigmoid mesocolic flaps, one peritoneal, preperitoneal fat and falciform ligament flap, one perivesical fat flap, one Gerota’s fat pad flap, and one bovine pericardial patch assisted pelvic exclusion. These flaps’ clinicopathological and operative characteristics, surgical outcomes, and technical aspects are described. Conclusions: When greater omentum is unavailable or inadequate and myofasciocutaneous flaps need to be avoided, local pedicled flaps using a range of intra-abdominal tissues or biological material can be used to fill the pelvis or occlude the pelvic inlet after proctectomy for Crohn’s disease. These techniques may help to prevent short and long-term complications associated with having a pelvic dead space.

BACKGROUND: Rising health care costs necessitate a reassessment of routine preoperative practices. Despite low transfusion rates in elective colorectal operations, many hospitals continue to perform routine preoperative type and screen testing. OBJECTIVE: To assess perioperative blood transfusion rates and determine preoperative and surgical factors associated with transfusions to determine whether the routine preoperative type and screen testing are necessary for elective abdominal colorectal surgeries, particularly in the setting of minimally invasive surgery. DESIGN: Retrospective cohort study. SETTINGS: Mayo Clinic, 2019–2023. PATIENTS: Adult patients undergoing elective abdominal colorectal operations. Exclusion criteria included emergent operations and nonabdominal procedures. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The primary outcome was the incidence of intraoperative and immediate postoperative (≤72 hours) blood product transfusion. Secondary outcomes assessed associations between transfusion rates, surgical approach, and preoperative variables. RESULTS: Among 4652 patients, 2770 underwent minimally invasive surgery and 1882 underwent open procedures. Perioperative red blood cell transfusion rates were lower in minimally invasive procedures (3.0% colectomy, 4.5% proctectomy) compared to open procedures (8.7% colectomy, 21.5% proctectomy). Open proctectomy was the strongest predictor of transfusion (OR 12.05; 95% CI, 8.94–16.26; p < 0.0001) followed by open colectomy (OR 2.59; 95% CI, 2.04–3.30; p < 0.0001). Preoperative factors including ASA class IV (OR 5.21; 95% CI, 1.09–24.82; p < 0.0382) and anemia (OR 4.14; 95% CI, 3.09–5.55; p < 0.0001) were also significantly associated with red blood cell transfusion. LIMITATIONS: The retrospective nature of the study may introduce selection bias. In addition, institutional practice patterns may limit the generalizability of findings. CONCLUSIONS: Patients undergoing elective minimally invasive colorectal surgery have very low rates of perioperative blood transfusions; thus, routine preoperative type and screen testing is likely unnecessary for this patient cohort. However, patients undergoing planned open operations, likely due to procedural complexity, and those who are ASA class IV, have preoperative anemia, or have anal cancer have higher transfusion risks and may benefit from selective testing. Implementing a risk-stratified approach based on surgical technique and patient comorbidities could potentially reduce unnecessary testing and associated health care costs. See Video Abstract. RE-TIPIFICACIÓN Y EVALUACIÓN PREOPERATORIAS: CÓMO IDENTIFICAR CUÁNDO ES NECESARIA UNA CIRUGÍA COLORRECTAL ELECTIVA ANTECEDENTES: El aumento en los costos de la atención médica exigen la reevaluación de las practicas preoperatorias de rutina. A pesar de las bajas tasas de transfusión en la cirugía colorrectal electiva, muchos hospitales continúan realizando pruebas de tipo y de cribado preoperatorios de forma rutinaria. El poresente estudio evalúa las tasas de transfusiones sanguíneas perioperatorias e identifica los factores asociados con éstas transfusiones para determinar la necesidad de pruebas de tipo y de cribado preoperatorios de forma rutinaria en cirugías colorrectales abdominales electivas. OBJETIVO: Evaluar las tasas de transfusión sanguínea perioperatoria y determinar los factores preoperatorios y quirúrgicos asociados con las transfusiones, con el fin de determinar si las pruebas de tipo y de cribado preoperatorias de forma rutinaria son necesarias en cirugías colorrectales abdominales electivas, en particular en el contexto de la cirugía mínimamente invasiva. DISEÑO: Estudio de cohortes retrospectivo. ESCENARIO: Clínica Mayo, 2019-2023. PACIENTES: Pacientes adultos sometidos a cirugías colorrectales abdominales electivas. Los criterios de exclusión incluyeron operaciones de emergencia y procedimientos no abdominales. INTERVENCIONES: Ninguna. PRINCIPALES MEDIDAS DE RESULTADOS: El resultado primario fue la incidencia de transfusión de hemoderivados intraoperatoriamente y postoperatoria inmediata (≤72 horas). Los resultados secundarios evaluaron la asociación entre las tasas de transfusión, el abordaje quirúrgico y las variables preoperatorias. RESULTADOS: De 4652 pacientes, 2770 se sometieron a cirugía mínimamente invasiva y 1882 a laparotomía. Las tasas de transfusión eritrocitaria perioperatoria fueron menores en los procedimientos mínimamente invasivos (3,0 % colectomía, 4,5 % proctectomía) que en los procedimientos abiertos (8,7 % colectomía, 21,5 % proctectomía). La proctectomía abierta fue el predictor más sólido de transfusión (OR: 12,05; IC del 95 %: 8,94-16,26; p < 0,0001), seguida de la colectomía abierta (OR: 2,59; IC del 95 %: 2,04-3,30; p < 0,0001). Los factores preoperatorios, incluyendo la clase ASA IV (OR 5,21; IC del 95 %: 1,09-24,82; p < 0,0382) y la anemia (OR 4,14; IC del 95 %: 3,09-5,55; p < 0,0001), también se asociaron significativamente con la transfusión de glóbulos rojos. LIMITACIONES: La naturaleza retrospectiva del estudio puede introducir sesgo de selección. Además, los patrones de práctica institucional pueden limitar la generalización de los hallazgos. CONCLUSIONES: Los pacientes sometidos a cirugía colorrectal mínimamente invasiva electiva tienen tasas muy bajas de transfusiones sanguíneas perioperatorias, por lo que las pruebas de detección y tipo de sangre preoperatorias de rutina probablemente sean innecesarias para esta cohorte de pacientes. Sin embargo, los pacientes sometidos a cirugías abiertas planificadas, probablemente debido a la complejidad del procedimiento, y aquellos con clase ASA IV, anemia preoperatoria o cáncer anal, tienen mayor riesgo de transfusión y podrían beneficiarse de pruebas selectivas. La implementación de un enfoque estratificado por riesgo basado en la técnica quirúrgica y las comorbilidades del paciente puede reducir las pruebas innecesarias y los costos de atención médica asociados. (Traducción—Dr. Xavier Delgadillo)

Abstract Introduction The objective of the study was to investigate the characteristics of patients who underwent surgery for dysplasia detected during chromoendoscopy (CE) surveillance for inflammatory bowel disease (IBD) and the incidence of cancer in the surgical specimen. Methods A retrospective review of medical records of all patients with dysplasia on a background of underlying IBD diagnosed through CE was carried out at a tri-site enterprise tertiary referral center between 2006 and 2019. We aimed to assess the clinical characteristics of patients requiring surgery for dysplasia and the incidence of cancer in the surgical specimen. Results Out of 219 patients with dysplasia on CE, 35 underwent surgery for dysplasia (16%). Indications for surgery were multifocal disease (n = 6), endoscopically unresectable lesions (n = 13), visible HGD (n = 7) and unifocal invisible LGD (n = 9). Out of 35 patients requiring surgery, 5 were found to have adenocarcinoma, one of whom with stage IIIB disease received postoperative chemotherapy. No patient with a pathologic diagnosis of adenocarcinoma had any evidence of recurrent disease after a mean postoperative follow-up of 32 months. Conclusions While the incidence of cancer at the time of surgery for IBD-related dysplasia is not negligible, the rate of node-positive disease is low.

Abstract Aim Reversal of diverting loop ileostomy (DLI) traditionally occurs at ≥12 weeks after formation. Early closure has been performed in attempts to reduce DLI‐associated morbidity. Therefore, the aim of this study was to determine whether time to stoma reversal impacts postoperative morbidity. Method A retrospective review was conducted using institutional‐level American College of Surgeons National Surgical Quality Improvement Program data for adult patients who underwent DLI closure between January 2012 and December 2021 across a multistate health system. Time to DLI closure was stratified into three groups: ≤12, 12–24 or 24–36 weeks. Additional data were obtained from the electronic medical record. The primary outcome was major morbidity after DLI closure. Results A total of 482 patients underwent DLI closure. Eighty four patients underwent closure at ≤12 weeks (17.4%), 300 at 12–24 weeks (62.2%) and 98 at 24–36 weeks (20.3%). The most common diagnosis at DLI formation was cancer ( n = 211, 43.8%). Patients in the ≤12 weeks closure group more commonly had ulcerative colitis or diverticular disease and a lower American Society of Anesthesiologists class than patients with closure at 24–36 weeks ( p < 0.05). There were no significant differences in complication severity, overall major morbidity or its individual components amongst the time to DLI closure groups. There were no differences in anastomotic leaks or need for laparotomy. On multivariable analysis, immunosuppressive therapy and preoperative haematocrit <30% were significant risk factors for major morbidity after DLI closure. Conclusion Major morbidity did not differ by time to DLI closure group, indicating that closure at ≤12 weeks is safe in selected patients.

AbstractAimCrohn's disease (CD) is regarded as a wasting disease, yet there is a growing population of CD patients with a body mass index (BMI) of 35 and above. The rate of postoperative complications is relatively high in CD patients but might be even higher in CD with morbid obesity (MO).MethodsThis was a retrospective study using a prospectively maintained database of all patients undergoing Ileocolic resection for CD between 2014 and 2021 in two referral centres, comparing postoperative complication rates according to BMI.ResultsThree hundred and forty‐six patients were identified. Sixty patients (17%) had a BMI over 30 kg/m2, and 28 (8.1%) had a BMI of over 35 kg/m2 (>35 group). The BMI >35 group had more women (78.6% vs. 52%, P < 0.1), a higher rate of patients not receiving an anastomosis (7.1% vs. 2.5%, P = 0.02), a higher rate of any postoperative surgical complication (32.1% vs. 25.2%, P = 0.4), with a higher rate of Clavien–Dindo ≥3 (14.3% vs. 7.2%, P = 0.25), a higher rate of stoma creation on reoperation for complications (7.2% vs. 1.7%, P = 0.04), a higher rate of 30‐day readmission due to intra‐abdominal abscess (10.7% vs. 4.7%, P = 0.2), but a lower rate of postoperative medical complications (3.6% vs. 15.7%, P < 0.01).ConclusionsThe rate of MO among CD patients requiring ileocolonic resection is on the rise. MO in this setting is associated with statistically non‐significant increases in all surgical complications, severe complications, readmission, and a higher chance for a bailout stoma creation upon reoperation. However, MO seems to be a protective factor for medical postoperative complications, which might suggest better nutritional status.

Objective: To compare robotic-assisted proctectomy with ileal pouch-anal anastomosis (R-IPAA) outcomes and laparoscopic proctectomy with IPAA within a specialized robotic surgery center, using matching techniques to minimize potential confounding factors. Background: Minimally invasive approaches, particularly laparoscopy, have improved outcomes for patients with inflammatory bowel disease and familial adenomatous polyposis undergoing IPAA. Robotic-assisted surgery offers potential technical advantages, but its definitive superiority over laparoscopy in this context remains under debate. Methods: This retrospective, “Strengthening the Reporting of Observational Studies in Epidemiology”–compliant study analyzed 234 consecutive patients undergoing IPAA (117 robotic and 117 laparoscopic). Data encompassed patient demographics, intraoperative details, and postoperative outcomes. We employed various matching techniques to address potential bias. Primary endpoints focused on 30-day complications, readmissions, and reoperations, with secondary endpoints including hospital stay, blood loss, and stoma closure rates. Results: R-IPAA demonstrated a lower conversion rate to open surgery ( P = 0.02), a shorter hospital stay ( P = 0.04), and reduced blood loss ( P = 0.0003) compared with laparoscopic proctectomy with IPAA. While overall 30-day morbidity rates were similar ( P = 0.4), matched analyses suggested a trend towards fewer reoperations and 3-month IPAA-associated complications after diverting loop ileostomy closure in the robotic group. However, these differences did not reach statistical significance. Conclusions: In a high-volume robotic surgery center, R-IPAA reduced the risk of conversion to open surgery while reducing intraoperative blood loss and providing shorter lengths of stay with equivalent perioperative outcomes. Promising trends to reduce 30-day reoperations and surgical complications after diverting loop ileostomy closure were observed after a matching analysis.

84 Background: Local therapies potentially offer a curative approach for patients with oligometastatic colorectal cancer (CRC). The effectiveness of systemic chemotherapy following definitive local treatment in this setting is not well-defined. Tumor-informed circulating tumor DNA (ctDNA) might guide management strategies after curative-intent local treatment. Methods: This is a single institution retrospective study of patients with CRC who underwent curative-intent local therapy to an isolated site of metastatic disease and had post-intervention tumor-informed ctDNA (Signatera) testing. The study was approved by the institutional review board. Clinical characteristics, including ctDNA results, were collected and evaluated. Kaplan-Meier method and log-rank test were used to calculate and compare disease-free survival (DFS). Factors associated with DFS were analyzed using multivariate Cox proportional hazards model. Results: 45 patients were included with median age of 59 years, 62% being male, 91% white, and 53% with stage IV disease at diagnosis. 37% of the patients had RAS mutations, no patient had BRAF mutation, and 2.2% patient had mismatch repair deficient disease. Isolated liver metastases were present in 80% of patients, lung metastases in 11% and other sites in 9%. 44 patients received chemotherapy prior to definitive treatment, with a median treatment duration of 16 weeks. ctDNA tests were done prior to local therapy in 23 patients, with 14 cases (61%) testing positive. Definitive treatment included resection (58%), ablation (13%), radiotherapy (4%), and multimodality (25%). Post-definitive treatment chemotherapy was administered to 24 (53%) patients. ctDNA positivity following definitive therapy was observed in 10 patients (22%), which was associated with a poorer prognosis, with a median DFS of 5.3 months compared to 21.3 months for the ctDNA-negative group (p<0.001). These findings were confirmed on multivariate analysis. In patients who had negative ctDNA after definitive local treatment, median DFS was 14.9 months for those who received post-intervention chemotherapy versus 21.3 months for those without post-intervention chemotherapy (p=0.835). Conclusions: Patients with negative ctDNA results following definitive local therapy for isolated metastatic CRC have better prognosis. Post-intervention chemotherapy in this group of patients was not associated with improved DFS. ctDNA guided omission of post-intervention chemotherapy following curative-intent local treatment of oligometastatic CRC warrants further study. [Table: see text]

BACKGROUND: IPAA has become the criterion standard for treating ulcerative colitis, familial adenomatous polyposis, and selected cases of Crohn’s colitis. Robotic surgery promises improved postoperative outcomes and decreased length of stay. However, few studies have evaluated the benefits of robotic IPAA compared to laparoscopy. OBJECTIVE: To compare short-term 30-day postoperative outcomes of robotic versus laparoscopic proctectomy with IPAA and diverting loop ileostomy. DESIGN: Retrospective observational study from a single, high-volume center. SETTINGS: Mayo Clinic, Rochester, Minnesota (tertiary referral center for IBD). PATIENTS: All adult patients undergoing minimally invasive proctectomy with IPAA and diverting loop ileostomy between January 2015 and April 2023. MAIN OUTCOME MEASURES: Thirty-day complications, hospital length of stay, estimated blood loss, conversion rate, 30-day readmission, and 30-day reoperation. RESULTS: Two hundred seventeen patients were included in the study; 107 underwent robotic proctectomy with IPAA and diverting loop ileostomy, whereas 110 had laparoscopic proctectomy with IPAA and diverting loop ileostomy. Operating time was significantly longer in the robotic group (263 ± 38 vs 228 ± 75 minutes, p < 0.0001). The robotic group also had lower estimated blood loss (81.5 ± 77.7 vs 126.8 ± 111.0 mL, p = 0.0006) as well as fewer conversions (0% vs 8.2%, p = 0.003). Patients in the robotic group received more intraoperative fluids (3099 ± 1140 vs 2472 ± 996 mL, p = 0.0001). However, there was no difference in length of stay, 30-day morbidity, 30-day readmission, 30-day reoperation, rate of diverting loop ileostomy closure at 3 months, and surgical IPAA complication rate after ileostomy closure. LIMITATIONS: Retrospective design, single-center study, potential bias because of the novelty of the robotic approach, and lack of long-term and quality-of-life outcomes. CONCLUSIONS: Robotic proctectomy with IPAA and diverting loop ileostomy may offer advantages in terms of estimated blood loss and conversion rate while maintaining the benefits of minimally invasive surgery. Further research is needed to evaluate long-term outcomes. See Video Abstract. NAVEGANDO EL PROGRESO: EXPERIENCIA DE OCHO AÑOS EN UN SOLO CENTRO CON PROCTECTOMÍA MÍNIMAMENTE INVASIVA Y ANASTOMOSIS ANAL-BOLSA ILEAL ANTECEDENTES: La anastomosis anal-bolsa ileal (IPAA) se ha convertido en el estándar de oro para el tratamiento de la colitis ulcerosa, la poliposis adenomatosa familiar y casos seleccionados de colitis de Crohn. La cirugía robótica promete mejores resultados posoperatorios y una menor duración de la estancia hospitalaria. Sin embargo, pocos estudios han evaluado los beneficios de la IPAA robótica en comparación con la laparoscopia. OBJETIVO: Comparar los resultados postoperatorios a corto plazo a 30 días de la proctectomía robótica versus laparoscópica con IPAA e ileostomía en asa de derivación. DISEÑO: Estudio observacional retrospectivo de un único centro de gran volumen. AJUSTES: Mayo Clinic, Rochester, Minnesota (centro terciario de referencia para EII). PACIENTES: Todos los pacientes adultos sometidos a proctectomía mínimamente invasiva con IPAA y DLI entre Enero de 2015 y Abril de 2023. PRINCIPALES MEDIDAS DE RESULTADOS: Complicaciones a los 30 días, duración de la estancia hospitalaria, pérdida de sangre estimada, tasa de conversión, reingreso a los 30 días y reoperación a los 30 días. RESULTADOS: Se incluyeron en el estudio 217 pacientes; 107 se sometieron a proctectomía robótica con IPAA y DLI, mientras que 110 se sometieron a proctectomía laparoscópica con IPAA y DLI. El tiempo operatorio fue significativamente mayor en el grupo robótico (263 ± 38 minutos versus 228 ± 75 minutos, p < 0,0001); la pérdida de sangre estimada (EBL) fue menor en el grupo robótico (81,5 ± 77,7 ml versus 126,8 ± 111,0 ml, p = 0,0006), así como el número de conversiones (0% versus 8,2%, p = 0,003). Los pacientes del grupo robótico recibieron más líquidos intraoperatorios (3099 ± 1140 ml versus 2472 ± 996 ml, p = 0,0001). Sin embargo, no hubo diferencias en la duración de la estancia hospitalaria, la morbilidad a los 30 días, el reingreso a los 30 días, la reoperación a los 30 días, la tasa de cierre del DLI a los tres meses y la tasa de complicaciones quirúrgicas de la IPAA después del cierre de la ileostomía. LIMITACIONES: Diseño retrospectivo, estudio unicéntrico, posible sesgo debido a la novedad del enfoque robótico, falta de resultados a largo plazo y de calidad de vida. CONCLUSIONES: La proctectomía robótica con IPAA y DLI puede ofrecer ventajas en términos de EBL y tasa de conversión, manteniendo al mismo tiempo los beneficios de la cirugía mínimamente invasiva. Se necesita más investigación para evaluar los resultados a largo plazo. (Traducción—Dr. Yesenia Rojas-Khalil)