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Shawki, Sherief

https://orcid.org/0000-0003-4065-890X

Mayo Clinic

Mayo Clinic

Citations 27

Robotic Redo Ileocolonic Resection for Crohn’s Disease: A Preliminary Report From a Tertiary Care Center
Calini, Giacomo , Saeed, Hamadelneel, D’Angelo, Anne-Lise D. , Shawki, Sherief , Mathis, Kellie L. , Calini, G , Aziz, Mohamed A. Abd El , Solafah, A , Behm, Kevin T. , Larson, David W.

Diseases of the Colon & Rectum | December 20, 2022 | Volume: 66 | Issue: 8 | Pages: 1095-1101

10.1097/dcr.0000000000002380 Get It

BACKGROUND: Although the safety of laparoscopic redo ileocolonic resection for Crohn’s disease has been described before, the safety of robotic redo ileocolonic resection is still unelucidated. OBJECTIVE: This study aimed to share our preliminary experience regarding the safety of robotic redo ileocolonic resection for Crohn’s disease. DESIGN: Retrospective analysis. SETTING: Tertiary care center. PATIENTS: All consecutive adult patients who underwent robotic ileocolonic resection for Crohn’s disease at our institution between 2014 and 2021 were included. Patients were divided into redo ileocolonic resection and primary ileocolonic resection groups. PRIMARY OUTCOME MEASURES: Baseline demographics, preoperative risk factors, and intraoperative details were compared between both groups. The primary outcome was conversion to an open approach, and secondary outcomes were 30-day postoperative complications. RESULTS: A total of 98 patients were included. Of them, 18 (18.4%) had a redo ileocolonic resection. Patients who had a redo ileocolonic resection were more likely to have a longer duration of disease, associated anoperineal disease, a higher number of previous lines of medical treatments, received total parental nutrition before the operation for correction of malnutrition, and longer time for adhesiolysis. Patients who had redo ileocolonic resection had a higher risk for conversion to open ileocolonic resection [3 (16.7%) versus 2 (2.5%); p value = 0.04]. There was no statistically significant difference regarding the overall length of stay and the 30-day morbidity between both groups. No 30-day mortality or anastomotic leaks occurred in either group. LIMITATIONS: Retrospective nature of the analysis. CONCLUSIONS: Robotic redo ileocolonic resection showed similar short-term postoperative outcomes to robotic primary ileocolonic resection for Crohn’s disease. However, conversion rates are higher in robotic redo ileocolonic resection yet seem lower than previously published results in laparoscopic surgery. See Video Abstract at http://links.lww.com/DCR/C77. RESECCIÓN ILEOCÓLICA ROBÓTICA REDO PARA LA ENFERMEDAD DE CROHN: INFORME PRELIMINAR DE UN CENTRO DE ATENCIÓN TERCIARIA ANTECEDENTES: Si bien la seguridad de la resección ileocolónica laparoscópica para la enfermedad de Crohn se ha descrito antes, la seguridad de la resección ileocolónica robótica aún no se ha dilucidado. OBJETIVO: Este estudio tuvo como objetivo compartir nuestra experiencia preliminar con respecto a la seguridad de la resección ileocolónica robótica para la enfermedad de Crohn. DISEÑO: Análisis retrospectivo. AJUSTE: Centro de atención terciaria. PACIENTES: Se incluyeron todos los pacientes adultos consecutivos que se sometieron a resección ileocolónica robótica por enfermedad de Crohn en nuestra institución entre 2014 y 2021. Los pacientes se dividieron en grupos de resección ileocolónica reconfeccionada y resección ileocolónica primaria. MEDIDAS DE RESULTADO: Se compararon los datos demográficos iniciales, los factores de riesgo preoperatorios y los detalles intraoperatorios entre ambos grupos. El resultado primario fue la conversión a abierto y los resultados secundarios fueron las complicaciones posoperatorias a los treinta días. RESULTADOS: Se incluyeron un total de 98 pacientes. De ellos, 18 (18,4%) tuvieron resección ileocolónica. Los pacientes que se sometieron a una nueva resección ileocolónica tenían más probabilidades de tener una mayor duración de la enfermedad, enfermedad anoperineal asociada, un mayor número de líneas previas de tratamientos médicos, más probabilidades de haber recibido nutrición parental total antes de la operación para la corrección de la desnutrición y más tiempo tiempo de adhesiolisis. Los pacientes que se sometieron a una nueva resección ileocolónica tuvieron un mayor riesgo de conversión a cirugía abierta [3 (16,7 %) frente a 2 (2,5 %); valor p 0,04]. No hubo diferencia estadísticamente significativa con respecto a la duración total de la estancia y la morbilidad a los treinta días entre ambos grupos. No hubo mortalidad a los treinta días ni fugas anastomóticas en ninguno de los grupos. LIMITACIONES: Naturaleza retrospectiva del análisis. CONCLUSIÓN: La resección ileocolónica robótica mostró resultados postoperatorios a corto plazo similares a la resección ileocolónica primaria robótica para la enfermedad de Crohn. Sin embargo, las tasas de conversión son más altas en la resección ileocolónica robótica, pero parecen más bajas que los resultados publicados previamente en la cirugía laparoscópica. Consulte Video Resumen en http://links.lww.com/DCR/C77. (Traducción—Dr Yolanda Colorado)
The “terminal line”: a novel sign for the identification of distal mesorectum end during TME for rectal cancer
Ghareeb, Waleed M. , Wang, Xiaojie , Zhao, Xiaozhen , Xie, Meirong, Shawki, Sherief , Chi, Pan , Chi, Pan , Emile, Sameh Hany

Gastroenterology Report | September 16, 2022 | Volume: 10 | Issue: No issue available | Pages: No page available

10.1093/gastro/goac050 Get It

Abstract Background Although the clinical importance of complete, intact total mesorectal excision (TME) is the widely accepted standard for decreasing local recurrence of rectal cancer, the residual mesorectum still represents a significant component of resection margin involvement. This study aimed to use a visible intraoperative sign to detect the distal mesorectal end to ensure complete inclusion of the mesorectum and avoid unnecessary over-dissection. Methods The distal mesorectum end was investigated retrospectively through a review of 124 operative videos at the Union Hospital of Fujian Medical University (Fujian, China) and Cleveland Clinic (Ohio, USA) by two independent surgeons who were blinded to each other. Furthermore, 28 cadavers and 44 post-operative specimens were prospectively examined by hematoxylin and eosin (H&E) staining and Masson's staining to validate and confirm the findings of the retrospective part. Univariate and multivariate analyses were carried out to detect the independent factors that can affect the visualization of the distal mesorectal end. Results The terminal line (TL) is the distal mesorectal end of the transabdominal and transanal TME (taTME) and appears as a remarkable pearly white fascial structure extending posteriorly from 2 to 10 o'clock. Histopathological examination revealed that the fascia propria of the rectum merges with the presacral fascia at the TL, beyond which the mesorectum ends, with no further downward extension. In the retrospective observation, the TL was seen in 56.6% of transabdominal TME and 56.0% of taTME operations. Surgical approach and tumor distance from the anal verge were the independent variables that directly influenced the detection of the TL (P = 0.03 and P = 0.01). Conclusion The TL is a visible sign where the transabdominal TME should end and the taTME should begin. Recognition of the mesorectal end may impact the certainty of complete mesorectum inclusion. Further clinical trials are needed to confirm the preliminary findings.
Turnbull–Cutait abdominoperineal pull‐through operation: The Cleveland Clinic experience in the 21st century
Lavryk, Olga , Bandi, Bethany, Shawki, Sherief , Floruta, Crina, Jia, Xue , Valente, Michael , Hull, Tracy L. , Steele, Scott R.

Colorectal Disease | May 1, 2022 | Volume: 24 | Issue: 10 | Pages: 1184-1191

10.1111/codi.16163 Get It

AbstractAimThe Turnbull–Cutait pull‐through procedure (TCO) restores intestinal continuity in the setting of chronic pelvic sepsis, colorectal anastomotic leak, complex pelvic fistulas and technical challenges related to complicated rectal cancer. The aim of this study was to evaluate the outcomes of the TCO for salvaging complex pelvic conditions and to compare it to hand‐sewn immediate coloanal anastomosis (CAA).MethodsThis is a retrospective single‐institution study where we searched a prospectively maintained database to identify patients who underwent the TCO. Patient demographics, operative indications and outcomes were analysed. TCO success was defined as maintenance of intestinal continuity and being stoma‐free. Kaplan–Meier analysis was employed for stoma‐free survival analysis.ResultsA total of 81 patients with TCO and 129 patients with CAA were included. The TCO success rate was 69% at a median of 1.4 years’ follow‐up with 25 (31%) patients ending up with a permanent stoma compared to 22 (17%) in the CAA group with a median follow‐up of 4 years (P = 0.03). The Kaplan–Meier cumulative incidence of TCO success at 1, 3 and 5 years was 79%, 60% and 51%, respectively, compared to 91%, 81% and 73% after CAA.ConclusionThe TCO has a high success rate for patients with complex pelvic conditions who may be facing a permanent stoma as their only option.
P446 Long-term Clinical Effectiveness And Stoma Outcome Of Fecal Diversion In Refractory Crohn’s Proctitis
Benammi, Sarah , Calini, Giacomo , Shawki, Sherief , Mathis, Kellie L. , Calini, G , Perry, William , Solafah, A , Larson, David W.

Journal of Crohn's and Colitis | January 21, 2022 | Volume: 16 | Issue: Supplement_1 | Pages: i426-i426

10.1093/ecco-jcc/jjab232.573 Get It

Abstract Background Proctectomy is often recommended when Crohn’s proctitis becomes refractory to medical therapy. However, some surgeons offer a temporary diverting stoma in an effort to avoid a permanent stoma. The long-term efficacy of this approach is not well-established. Our aim was to determine the long-term effectiveness of fecal diversion in patients with refractory Crohn’s proctitis. Methods This retrospective study included all patients with Crohn’s proctitis who underwent formation of a diverting ileostomy or colostomy for refractory disease from, 1998 to, 2019 in Mayo Clinic Rochester MN. Outcomes were disease recurrence, rate of stoma closure, and proctectomy. Univariate comparisons among categorical variables were performed with Pearson’s Chi-square and continuous variables using the student t-test. The cumulative probability of stoma closure was performed with a Kaplan Meier log-rank analysis. Multivariable analysis of risk factors for proctectomy and permanent stoma was achieved with logistic regression. Results Ninety-seven patients (55.7% female) were included. Ileostomy was the most common stoma type (88.7%, n=86), and colostomy was (11.3%, n=11) (Table.1). Median follow-up was, 4 years (range, 0–14). Active Crohn’s at follow-up was reported in, 68.1%. Only, 41.2% of patients underwent attempt at stoma reversal, and, 42.3% required a proctectomy (median, 19.5 months after diversion). At last follow-up, 29.9% were stoma-free, 42.3% had a new permanent stoma, and, 27.8% had the original diverting stoma (Fig.1). The multivariable predictors of proctectomy and permanent stoma were the recurrence of active CD after diversion and the need for other CD-related surgery following stoma creation (Table.2). The limitations of the study are its small sample size and its retrospective nature. The cumulative probability of stoma closure was performed with a Kaplan Meier log-rank analysis (Fig.2). Conclusion Diversion is effective at alleviating symptoms of Crohn’s proctitis in selected patients but does not significantly change disease outcome. Only a small number can avoid a long-term stoma.
Postoperative Safety Profile of Minimally Invasive Ileocolonic Resections for Crohn’s Disease in the Era of Biologic Therapy
Aziz, Mohamed A. Abd El , Calini, Giacomo , Saeed, Hamadelneel, Stocchi, Luca , Merchea, Amit , Shawki, Sherief , Abd El Aziz, Mohamed A , Solafah, A , Calini, G , Colibaseanu, Dorin T, Colibaseanu, Dorin , Larson, David W.

Journal of Crohn's and Colitis | January 14, 2022 | Volume: 16 | Issue: 7 | Pages: 1079-1088

10.1093/ecco-jcc/jjac012 Get It

Abstract Background There is controversy regarding the postoperative outcomes in Crohn’s disease [CD] patients exposed to vedolizumab [VDZ] or ustekinumab [UST]. We aimed to describe our surgical outcomes in patients who underwent minimally invasive ileocolonic resection [MIS-ICR] for CD who had preoperative biologic therapy. Methods All consecutive adult patients who had MIS-ICR for CD between 2014 and 2021 at our institution were included. Patients were divided into four groups: VDZ, UST, anti-tumour necrosis factor [anti-TNF], and no biologic group. Timing between the last dose of biologics and surgery was per surgeon’s discretion. The primary outcome was intra-abdominal septic complications. Secondary outcomes included all 30-day complications. Results A total of 274 patients were identified. Of these, 113 [41.2%] patients had received anti-TNF, 52 [19%] had received UST, and 19 [7%] had received VDZ. There was no difference between the four groups regarding baseline risk factors. There was no difference between the four groups regarding intra-abdominal septic complications [4.4% for no biologic, 5.3% for anti-TNF, 5.8% for UST, and 5.3% for VDZ; p = 0.987], surgical site infection rate, overall 30-day morbidity, overall 30-day readmission, overall surgical and medical complications, urinary tract infection, pulmonary infections, or length of stay. Those results were consistent after a subgroup analysis based on complexity of the disease. Conclusions This retrospective analysis demonstrates an equivalent postoperative safety profile for patients treated with preoperative anti-TNF, VDZ, or UST versus no biologic therapy within 3 months of MIS-ICR for Crohn’s disease. Preoperative biologic therapy may not increase complications after minimally invasive ileocolonic resection in Crohn’s disease. Further studies with larger sample sizes are needed to confirm results.
Emergent and Urgent Surgery for Ulcerative Colitis in the United States in the Minimally Invasive and Biologic Era
D’Angelo, Anne-Lise D. , Raffals, Laura E. , Mathis, Kellie L. , Shawki, Sherief , D'Angelo, Anne-Lise D, Kelley, Scott R. , Aziz, Mohamed A. Abd El , Larson, David W. , Grass, Fabian

Diseases of the Colon & Rectum | December 13, 2021 | Volume: 65 | Issue: 8 | Pages: 1025-1033

10.1097/dcr.0000000000002109 Get It

BACKGROUND: Although the overall adoption of minimally invasive surgery in the nonemergent management of ulcerative colitis is established, little is known about its utilization in emergency settings. OBJECTIVE: The goal of this study was to assess rates of urgent and emergent surgery over time in the era of emerging biologic therapies and to highlight the current practice in the United States regarding the utilization of minimally invasive surgery for urgent and emergent indications for ulcerative colitis. DESIGN: This was a retrospective analysis study. SETTINGS: Data were collected from the American College of Surgeons National Quality Improvement Program database. PATIENTS: All adult patients who underwent emergent or urgent colectomy for ulcerative colitis were included. MAIN OUTCOME MEASURES: Rates of emergency operations over time and utilization trends of minimally invasive surgery in urgent and emergent settings were assessed. Unadjusted and adjusted overall, surgical, and medical 30-day complication rates were compared between open and minimally invasive surgery. RESULTS: A total of 2219 patients were identified. Of those, 1515 patients (68.3%) underwent surgery in an urgent setting and 704 (31.7%) as an emergency. Emergent cases decreased over time (21% in 2006 to 8% in 2018; p < 0.0001). However, the rate of urgent surgeries has not significantly changed (42% in 2011 to 46% in 2018; p = 0.44). Minimally invasive surgery was offered to 70% of patients in the urgent group (1058/1515) and 22.6% of emergent indications (159/704). Overall, minimally invasive surgery was increasingly utilized over the study period in urgent (38% in 2011 to 71% in 2018; p < 0.0001) and emergent (0% in 2005 to 42% in 2018; p < 0.0001) groups. Compared to minimally invasive surgery, open surgery was associated with a higher risk of surgical, septic, and overall complications, and prolonged hospitalization. LIMITATIONS: This study was limited by its retrospective nature of the analysis. CONCLUSION: Based on a nationwide analysis from the United States, minimally invasive surgery has been increasingly and safely implemented for emergent and urgent indications for ulcerative colitis. Although the sum of emergent and urgent cases remained the same over the study period, emergency cases decreased significantly over the study period, which may be related to improved medical treatment options and a collaborative, specialized team approach. See Video Abstract at http://links.lww.com/DCR/B847. CIRUGÍA DE URGENCIA Y EMERGENCIA PARA LA COLITIS ULCEROSA EN LOS ESTADOS UNIDOS EN LA ERA MÍNIMAMENTE INVASIVA Y DE TERAPIA BIOLÓGICA ANTECEDENTES: Si bien se ha establecido la adopción generalizada de la cirugía mínimamente invasiva en el tratamiento electivo de la colitis ulcerosa, se sabe poco sobre su utilización en situaciones de emergencia. OBJETIVO: Evaluar las tasas de cirugía de urgencia a lo largo del tiempo en la era de las terapias biológicas emergentes y destacar la práctica actual en los Estados Unidos con respecto a la utilización de la cirugía mínimamente invasiva para las indicaciones de urgencia y emergencia de la colitis ulcerosa. DISEÑO: Análisis retrospectivo. AJUSTES: Base de datos del Programa Nacional de Mejoramiento de la Calidad del Colegio Americano de Cirujanos. PACIENTES: Todos los pacientes adultos que se sometieron a colectomía de emergencia o urgencia por colitis ulcerosa. MEDIDAS DE RESULTADO: Se evaluaron las tasas de operaciones de emergencia a lo largo del tiempo y las tendencias de utilización de la cirugía mínimamente invasiva en entornos de urgencia y emergencia. Se compararon las tasas de complicaciones generales, quirúrgicas y médicas de 30 días no ajustadas y ajustadas entre la cirugía abierta y la mínimamente invasiva. RESULTADOS: Se identificaron un total de 2.219 pacientes. De ellos, 1.515 pacientes (68,3%) fueron intervenidos de urgencia y 704 (31,7%) de emergencia. Los casos emergentes disminuyeron con el tiempo (21% en 2006 a 8% en 2018; p <0,0001). Sin embargo, la tasa de cirugías urgentes no ha cambiado significativamente (42% en 2011 a 46% en 2018, p = 0,44). Se ofreció cirugía mínimamente invasiva al 70% de los pacientes del grupo urgente (1.058 / 1.515) y al 22,6% de las emergencias (159/704). En general, la cirugía mínimamente invasiva se utilizó cada vez más durante el período de estudio en grupos urgentes (38% en 2011 a 71% en 2018; p <0,0001) y emergentes (0% en 2005 a 42% en 2018; p <0,0001). En comparación con la cirugía mínimamente invasiva, la cirugía abierta se asoció con un mayor riesgo de complicaciones generales, quirúrgicas, sépticas y hospitalización prolongada. LIMITACIONES: Carácter retrospectivo del análisis. CONCLUSIÓNES: Basado en un análisis nacional de los Estados Unidos, la cirugía mínimamente invasiva se ha implementado de manera creciente y segura para las indicaciones emergentes y urgentes de la colitis ulcerosa. Si bien la suma de casos emergentes y urgentes permaneció igual durante el período de estudio, los casos de emergencia disminuyeron significativamente, lo que puede estar relacionado con mejores opciones de tratamiento médico y un enfoque de equipo colaborativo y especializado. Consulte Video Resumen en http://links.lww.com/DCR/B847. (Traducción—Dr. Felipe Bellolio)
Redo IPAA After a Failed Pouch In Patients With Crohn’s Disease: Is It Worth Trying?
Lavryk, Olga , Stocchi, Luca , Shawki, Sherief , Aiello, Alexandra , Hull, Tracy L. , Church, James M. , Steele, Scott R.

Diseases of the Colon & Rectum | March 9, 2020 | Volume: 63 | Issue: 6 | Pages: 823-830

10.1097/dcr.0000000000001644 Get It

BACKGROUND: In selected patients with ulcerative colitis and pelvic pouch failure, redo pouch is an option. However, it is unknown whether selected patients with Crohn’s disease should be offered a chance to avoid permanent diversion after failure of IPAA. OBJECTIVE: The objective was to compare the outcomes of redo pouch for ulcerative colitis and Crohn’s disease. DESIGN: This was a retrospective analysis of a prospectively maintained pouch database (1983–2017). SETTINGS: The setting was the Cleveland Clinic. PATIENTS: This study included patients who underwent redo pouch with a primary surgical specimen diagnosis of ulcerative or Crohn’s colitis at the time of initial pouch. MAIN OUTCOME MEASURES: Pouch failure was defined as either pouch excision or indefinite pouch diversion. Patient characteristics, perioperative and functional outcomes, pouch survival, and quality of life were compared according to the diagnosis. RESULTS: Of 422 patients, 392 had ulcerative colitis and 30 had Crohn’s disease. Age and sex were comparable. The most common indications for redo pouch included anastomotic separation and fistulas (220 (56.1%) in ulcerative colitis and 21 (70%) in Crohn’s disease). The majority of redo pouches required mucosectomy with handsewn anastomosis (310 (79%) in ulcerative colitis and 30 (100%) in Crohn’s disease; p = 0.23). A new pouch was constructed in 160 patients (41%) with ulcerative colitis and repair of old pouch in 231 patients (59%) compared with 25 (83%) in Crohn’s disease, who had creation of new pouch; only in 5 (17%) was the old pouch re-anastomosed. Stool frequency, seepage, and fecal urgency were comparable between groups. Cumulative 5-year pouch survival was longer in ulcerative colitis versus Crohn’s disease (88% vs 55%; p = 0.008). Major causes of redo failure in Crohn’s disease were pouch fistulas and/or strictures occurring after ileostomy closure. These were more common in Crohn’s disease than in ulcerative colitis (p < 0.001). LIMITATIONS: This was a retrospective design. CONCLUSIONS: Redo pouch can be offered to selected patients with colonic Crohn’s disease diagnosed at the time of their primary pouch. See Video Abstract at http://links.lww.com/DCR/B206. Rehacer la Anastomosis Ileoanal con Reservorio Después de un Reservorio Ileal Fallido en Pacientes con Enfermedad de Crohn: ¿Vale la Pena Intentarlo? ANTECEDENTES: En pacientes seleccionados con colitis ulcerativa y falla del reservorio pélvico, rehacer el reservorio es una opción. Sin embargo, se desconoce si en los pacientes seleccionados con enfermedad de Crohn se debería ofrecer la oportunidad de evitar la derivación permanente después de la falla de la anastomosis ileoanal con reservorio ileal. OBJETIVO: El objetivo fue comparar los resultados de reservorios re-hechos en colitis ulcerosa y la enfermedad de Crohn. ESCENARIO: El escenario fue la Cleveland Clinic. DISEÑO: Análisis retrospectivo de una base de datos de reservorios ileales mantenida prospectivamente (1983-2017). PACIENTES: Este estudio incluyó a pacientes que se sometieron a cirugía para rehacer el reservorio ileal con un diagnóstico en el espécimen quirúrgico primario de colitis ulcerosa o de Crohn en el momento del reservorio inicial. PRINCIPALES MEDIDAS DE RESULTADO: La falla del reservorio se definió como la escisión del reservorio o la derivación indefinida del reservorio. Las características del paciente, los resultados perioperatorios y funcionales, la supervivencia del reservorio y la calidad de vida se compararon de acuerdo con el diagnóstico. RESULTADOS: De 422 pacientes, 392 tenían colitis ulcerativa y 30 tenían enfermedad de Crohn. La edad y el género fueron comparables. Las indicaciones más comunes para rehacer el reservorio incluyeron dehiscencia anastomótica y fístulas [220 (56,1%) en colitis ulcerosa y 21 (70%) en la enfermedad de Crohn]. La mayoría de los reservorios rehechos requirieron mucosectomía con anastomosis manual [310 (79%) en colitis ulcerosa y 30 (100%) en la enfermedad de Crohn, p = 0.23]. Se construyó un nuevo reservorio en 160 (41%) pacientes con colitis ulcerativa y se reparó el reservorio antiguo en 231 (59%) pacientes, en comparación con 25 (83%) en la enfermedad de Crohn, que requirieron creación de un nuevo reservorio, y solo 5 (17%) donde el reservorio antiguo se volvió a anastomosar. La frecuencia de las evacuaciones, el manchado fecal y la urgencia fecal fueron comparables entre grupos. La supervivencia acumulada del reservorio a 5 años fue mayor en la colitis ulcerativa frente a la enfermedad de Crohn (88% frente a 55%, p = 0.008). Las principales causas de falla del reservorio rehecho en la enfermedad de Crohn fueron las fístulas del reservorio y / o las estenosis que ocurrieron después del cierre de ileostomía. Estas fueron más comunes en la enfermedad de Crohn que en la colitis ulcerativa (p <0.001). LIMITACIONES: Este fue un diseño retrospectivo. CONCLUSIÓN: Rehacer el reservorio ileal se puede ofrecer a pacientes seleccionados con enfermedad de Crohn colónica diagnosticada en el momento de su reservorio primario. Consulte Video Resumen en http://links.lww.com/DCR/B206. (Traducción—Dr Jorge Silva Velazco)