Ketamine intolerance in patients on enhanced recovery after surgery protocols undergoing colorectal operations.

BACKGROUND: Ketamine is used in enhanced recovery after surgery (ERAS) protocols because of its beneficial antihyperalgesic and antitolerance effects. However, adverse effects such as hallucinations, sedation, and diplopia could limit ketamine's utility. The main objective of this study was to identify rates of ketamine side effects in postoperative patients after colorectal surgery and, secondarily, to compare short-term outcomes between patients receiving ketamine analgesia and controls. METHODS: This was a retrospective observational cohort study. Subjects were adults who underwent ERAS protocol-guided colorectal surgery at a large, integrated health system. Patients were grouped into ketamine-receiving and preketamine cohorts. Patients receiving ketamine were divided into tolerant and intolerant groups. Propensity score-adjusted models tested multivariate associations of ketamine tolerance/intolerance vs control group. RESULTS: A total of 732 patients underwent colorectal surgery within the ERAS program before ketamine's introduction (control). After ketamine's introduction, 467 patients received the medication. Intolerance was seen in 29% of ketamine recipients, and the most common side effect was diplopia. Demographics and surgical variables did not differ between cohorts. Multivariate models revealed no significant differences in hospital stays. Pain scores in the first 24 hours after surgery were slightly higher in patients receiving ketamine. Opiate consumption after surgery was lower for both ketamine tolerant and ketamine intolerant cohorts than for controls. CONCLUSION: Rates of ketamine intolerance are high, which can limit its use and potential effectiveness. Ketamine analgesia significantly reduced opiate consumption without increasing hospital stays after colorectal surgery, regardless of whether it was tolerated.

Colorectal cancer genetic referral: Are we doing enough?

Purpose: Guidelines are published for referral to genetic counseling and multigene panel genetic testing for colorectal cancer. We hypothesize that these guidelines are not recognized in practice, resulting in the underreferral of patients to genetic counseling. We aimed to investigate the clinical impact of these guidelines. Methods: This was a retrospective cohort study conducted using a single academic-institution colorectal cancer patient registry. The registry included all patients ≥18 years old with a pathologic diagnosis of colon cancer, rectal cancer, or polyposis from January 2018 to January 2020 with complete chart data to determine inclusion into the genetic referral cohort. Results: Out of 225 colon cancer patients, 92 met criteria for referral to genetic testing, but only 56 patients obtained referral and 39 completed testing. For rectal cancer, 29 out of 127 patients met criteria for referral, but only 11 obtained referral and 8 completed testing. Actionable variants, defined as pathogenic or likely pathogenic, were identified in 18 colon cancer and 5 rectal cancer patients. Age made a significant difference in the referral rate for colon cancer (P = 0.02) but not rectal cancer (P > 0.05). Conclusion: Our study demonstrates poor adherence to guideline-based genetic testing. These data emphasize the need for more consistent referral to genetic testing for diagnosis of underlying inherited cancer syndromes.

Sixth Annual Enhanced Recovery After Surgery Symposium highlights: work in progress or standard care?

Enhanced Recovery After Surgery (ERAS) protocols have demonstrated effectiveness in accelerating patient recovery and improving outcomes. Since the systemwide implementation of ERAS protocols at Baylor Scott & White Health, an annual multidisciplinary conference has provided a review of outcomes and advancements in the ERAS program. This meeting, coined the ERAS symposium, allows providers who utilize recovery protocols to collaborate with national and international leaders in the field to improve the clinical care of patients. The sixth annual ERAS symposium was held on February 10, 2023, and provided key presentations that discussed the latest results from ERAS efforts across multiple surgical specialties along with updates in anesthesia, nursing, and nutrition. A summary of those presentations, which included perioperative glycemic control, misconceptions in pain management, and emerging ERAS protocols in different surgical specialties, is provided to document the system progress.

Using an Educational Intervention to Map our Surgical Teams' Function, Emotional Intelligence, Communication and Conflict Styles.

OBJECTIVE: The leadership team invited surgical team members to participate in educational sessions that created self and other awareness as well as gathered baseline information about these topics: communication, conflict management, emotional intelligence, and teamwork. DESIGN: Each educational session included an inventory that was completed to help participants understand their own characteristics and the characteristics of their team members. The results from these inventories were aggregated, relationships were identified, and the intervention was evaluated. SETTING: A level 1 trauma center, Baylor Scott and White Health, in central Texas; a 636-bed tertiary care main hospital and an affiliated children's hospital. PARTICIPANTS: An open invitation for all surgical team members yielded 551 interprofessional OR team members including anesthesia, attending physicians, nursing, physician assistants, residents, and administration. RESULTS: Surgeons' communication styles were individual focused, while other team members were group focused. The most common conflict management mode for surgical team members on average was avoiding, and the least common was collaborating. Surgeons primarily used competing mode for conflict management, with avoiding coming in a close second. Finally, the 5 dysfunctions of a team inventory revealed low accountability scores, meaning the participants struggled with holding team members accountable. CONCLUSIONS: Helping team members understand their own and others' strengths and blind spots will help create opportunity for more purposeful and clear communication. Additionally, this knowledge should improve efficiency and safety in the high-stakes environment of the operating room.

Predictive factors of first-time failure on the American Board of Colorectal Surgery certifying and qualifying examinations.

Objective: To discover if first-attempt failure of the American Board of Colon and Rectal Surgery (ABCRS) board examination is associated with surgical training or personal demographic characteristics. Methods: Current colon and rectal surgery program directors in the United States were contacted via email. Deidentified records of trainees from 2011 to 2019 were requested. Analysis was performed to identify associations between individual risk factors and failure on the ABCRS board examination on the first attempt. Results: Seven programs contributed data, totaling 67 trainees. The overall first-time pass rate was 88% (n = 59). Several variables demonstrated potential for association, including Colon and Rectal Surgery In-Training Examination (CARSITE) percentile (74.5 vs 68.0, P = 0.09), number of major cases in colorectal residency (245.0 vs 219.2, P = 0.16), >5 publications during colorectal residency (75.0% vs 25.0%, P = 0.19), and first-time passage of the American Board of Surgery certifying examination (92.5% vs 7.5%, P = 0.18). Conclusion: The ABCRS board examination is a high-stakes test, and training program factors may be predictive of failure. Although several factors showed potential for association, none reached statistical significance. Our hope is that by increasing our data set, we will identify statistically significant associations that can potentially benefit future trainees in colon and rectal surgery.

National trends in distribution of underrepresented minorities within United States general surgery residency programs: A longitudinal panel study.

BACKGROUND: Cultural affinity with a provider improves satisfactoriness of healthcare. We examined 2005-2019 trends in racial/ethnic diversity/inclusion within general surgery residency programs. METHODS: We triangulated 2005-2019 race/ethnicity data from Association of American Medical Colleges surveys of 4th-year medical students, the Electronic Residency Application Service, and Accreditation Council for Graduate Medical Education-affiliated general surgery residencies. Temporal trends in minority representation were tested for significance. RESULTS: Underrepresented racial/ethnic minorities in medicine (URiMs) increased among graduating MDs from 7.6% in 2005 to 11.8% in 2019 (p < 0.0001), as did their proportion among surgery residency applicants during 2005-2019 (p < 0.0001). However, proportions of URiMs among general surgery residents (≈8.5%), and of programs without URiMs (≈18.8%), stagnated. CONCLUSIONS: Growing URiM proportions among medical school graduates and surgery residency applicants did not improve URiM representation among surgery trainees nor shrink the percentage of programs without URiMs. Deeper research into motivators underlying URiMs' residency program preferences is warranted.

Primary Colorectal Cancer.

Over the last few decades, the colorectal surgery world has seen a paradigm shift in the care of patients. The introduction of minimally invasive techniques led to the development of procedures resulting in reduced patient morbidity and hospital stay. The vetting process of minimally invasive colorectal surgery involved rigorous studies to ensure that oncologic outcomes were not being compromised. In this chapter, we discuss the most relevant randomized controlled trials that support the practice of minimally invasive colorectal surgery. The multimodal treatment of rectal cancer has developed rapidly, resulting in improved survival and decreased morbidity and mortality. In this review, we also present the latest evidence behind the multidisciplinary approach to rectal cancer.

Practical Guide to Surgical Clinical Trial Implementation, Oversight, and Regulatory Aspects.

This Guide to Statistics and Methods describes the steps necessary for a successful trial implementation that can safeguard credible results and conclusions while minimizing potential harm.

Objective metrics for hand-sewn bowel anastomoses can differentiate novice from expert surgeons.

BACKGROUND: Assessing performance automatically in a virtual reality trainer or from recorded videos is advantageous but needs validated objective metrics. The purpose of this study is to obtain expert consensus and validate task-specific metrics developed for assessing performance in double-layered end-to-end anastomosis. MATERIALS AND METHODS: Subjects were recruited into expert (PGY 4-5, colorectal surgery residents, and attendings) and novice (PGY 1-3) groups. Weighted average scores of experts for each metric item, completion time, and the total scores computed using global and task-specific metrics were computed for assessment. RESULTS: A total of 43 expert surgeons rated our task-specific metric items with weighted averages ranging from 3.33 to 4.5 on a 5-point Likert scale. A total of 20 subjects (10 novices and 10 experts) participated in validation study. The novice group completed the task significantly more slowly than the experienced group (37.67 ± 7.09 vs 25.47 ± 7.82 min, p = 0.001). In addition, both the global rating scale (23.47 ± 4.28 vs 28.3 ± 3.85, p = 0.016) and the task-specific metrics showed a significant difference in performance between the two groups (38.77 ± 2.83 vs 42.58 ± 4.56 p = 0.027) following partial least-squares (PLS) regression. Furthermore, PLS regression showed that only two metric items (Stay suture tension and Tool handling) could reliably differentiate the performance between the groups (20.41 ± 2.42 vs 24.28 ± 4.09 vs, p = 0.037). CONCLUSIONS: Our study shows that our task-specific metrics have significant discriminant validity and can be used to evaluate the technical skills for this procedure.

Development and Validation of Task-Specific Metrics for the Assessment of Linear Stapler-Based Small Bowel Anastomosis.

INTRODUCTION: Task-specific metrics facilitate the assessment of surgeon performance. This 3-phased study was designed to (1) develop task-specific metrics for stapled small bowel anastomosis, (2) obtain expert consensus on the appropriateness of the developed metrics, and (3) establish its discriminant validity. METHODS: In Phase I, a hierarchical task analysis was used to develop the metrics. In Phase II, a survey of expert colorectal surgeons established the importance of the developed metrics. In Phase III, to establish discriminant validity, surgical trainees and surgeons, divided into novice and experienced groups, constructed a side-to-side anastomosis on porcine small bowel using a linear cutting stapler. The participants' performances were videotaped and rated by 2 independent observers. Partial least squares regression was used to compute the weights for the task-specific metrics to obtain weighted total score. RESULTS: In Phase II, a total of 45 colorectal surgeons were surveyed: 28 with more than 15 years, 13 with 5 to 15 years, and 4 with less than 5 years of experience. The consensus was obtained on all the task-specific metrics in the more experienced groups. In Phase III, 20 subjects participated equally in both groups. The experienced group performed better than the novice group regardless of the rating scale used: global rating scale (p = 0.009) and the task-specific metrics (p = 0.012). After partial least squares regression, the weighted task-specific metric score continued to show that the experienced group performed better (p < 0.001). CONCLUSION: Task-specific metric items were developed based on expert consensus and showed good discriminant validity compared with a global rating scale between experienced and novice operators. These items can be used for evaluating technical skills in a stapled small bowel anastomosis model.

Development of the Breast Surgical Oncology Fellowship in the United States.

The surgical treatment of breast cancer has rapidly evolved over the past 50 years, progressing from Halsted's radical mastectomy to a public campaign of surgical options, aesthetic reconstruction, and patient empowerment. Sparked by the research of Dr. Bernard Fisher and the first National Surgical Adjuvant Breast and Bowel Project trial in 1971, the field of breast surgery underwent significant growth over the next several decades, enabling general surgeons to limit their practices to the breast. High surgical volumes eventually led to the development of the first formal breast surgical oncology fellowship in a large community-based hospital at Baylor University Medical Center in 1982. The establishment of the American Society of Breast Surgeons, as well as several landmark clinical trials and public campaign efforts, further contributed to the advancement of breast surgery. In 2003, the Society of Surgical Oncology (SSO), in partnership with the American Society of Breast Surgeons and the American Society of Breast Disease, approved its first fellowship training program in breast surgical oncology. Since that time, the number of American fellowship programs has increased to approximately 60 programs, focusing not only on training in breast surgery, but also in medical oncology, radiation oncology, pathology, breast imaging, and plastic and reconstructive surgery. This article focuses on the happenings in the United States that led to the transition of breast surgery from a subset of general surgery to its own specialized field.

Specialization improves outcomes in rectal cancer surgery.

SCOPE OF SPECIALTY: Colorectal surgery encompasses any procedure performed on the colon and/or rectum. This section focuses on rectal surgery, specifically regarding surgery for rectal cancer and its technical complexity and disease complexity that often requires a multidisciplinary team-based approach. The emergence of rectal cancer surgical specialists exhibits improvements in rectal cancer outcomes. Colorectal surgery fellowships are available for general surgeons who desire specialization. Roughly 70 colorectal surgery fellowship programs exist, of which 39 are accredited by the National Accreditation Program for Rectal Cancer (NAPRC). PATIENT CARE AND QUALITY OUTCOMES: The OSTRiCh (Optimizing the Surgical Treatment of Rectal Cancer) Consortium (OC) and NAPRC developed guidelines for a standardized pathway for rectal cancer care and outline standards for patient care and performance indicators. These efforts focus on the recognition of disparities in rectal cancer outcomes, a system for improvement, delivery of quality care, and optimizing patient results by minimizing morbidity and mortality. REGULATORY REQUIREMENTS: In the United States, Board certification for surgeons performing colorectal surgery is granted by the American Board of Colon and Rectal Surgery (ABCRS). While the United States lags behind its European counterparts in development of rectal cancer quality measures, significant changes have been made to close the gap. Improvement initiatives launched by the OC implemented a myriad of quality metrics for longitudinal outcome tracking; surgical site infection, positive circumferential margin rate, rate of colostomy creation, recurrence rate, to name a few.

Impact of Patient-Reported Penicillin Allergy on Antibiotic Prophylaxis and Surgical Site Infection Among Patients Undergoing Colorectal Surgery.

BACKGROUND: Surgical site infections are a major preventable source of morbidity, mortality, and increased health care expenditures after colorectal surgery. Patients with penicillin allergy may not receive the recommended preoperative antibiotics, putting them at increased risk for surgical site infections. OBJECTIVE: This study aimed to evaluate the impact of patient-reported penicillin allergy on preoperative antibiotic prophylaxis and surgical site infection rates among patients undergoing major colon and rectal procedures. DESIGN: This is a retrospective observational study. SETTING: This study was conducted at a tertiary teaching hospital in Dallas. PATIENTS: Adults undergoing colectomy or proctectomy between July 2012 and July 2019 were included. MAIN OUTCOME MEASURES: The primary outcomes measured were preoperative antibiotic choice and surgical site infection. RESULTS: Among 2198 patients included in the study, 12.26% (n = 307) reported a penicillin allergy. Patients with penicillin allergy were more likely to be white (82%) and female (54%; p < 0.01). The most common type of allergic reaction reported was rash (36.5%), whereas 7.2% of patients reported anaphylaxis. Patients with self-reported penicillin allergy were less likely to receive beta-lactam antibiotics than patients who did not report a penicillin allergy (79.8% vs 96.7%, p < 0.001). Overall, 143 (6.5%) patients had surgical site infections. On multivariable logistic regression, there was no difference in rates of surgical site infection between patients with penicillin allergy vs those without penicillin allergy (adjusted OR 1.14; 95% CI, 0.71-1.82). LIMITATIONS: A limitation of this study was its retrospective study design. CONCLUSIONS: Self-reported penicillin allergy among patients undergoing colorectal surgery is common; however, only a small number of these patients report any serious adverse reactions. Patients with self-reported penicillin allergy are less likely to receive beta-lactam antibiotics and more likely to receive non-beta-lactam antibiotics. However, this does not affect the rate of surgical site infection among these patients, and these patients can be safely prescribed non-beta-lactam antibiotics without negatively impacting surgical site infection rates. See Video Abstract at http://links.lww.com/DCR/B838 .IMPACTO DE LA ALERGIA A LA PENICILINA INFORMADA POR EL PACIENTE EN LA PROFILAXIS ANTIBIÓTICA Y LA INFECCIÓN DEL SITIO OPERATORIO ENTRE PACIENTES DE CIRUGÍA COLORECTAL. ANTECEDENTES: Las infecciones del sitio operatorio son una de las principales fuentes prevenibles de morbilidad, mortalidad y aumento del gasto sanitario después de cirugía colorrectal. Es posible que los pacientes con alergia a la penicilina no reciban los antibióticos preoperatorios recomendados, lo que los pone en mayor riesgo de infecciones en el sitio operatorio. OBJETIVO: Este estudio tuvo como objetivo evaluar el impacto de la alergia a la penicilina informada por el paciente sobre la profilaxis antibiótica preoperatoria y las tasas de infección del sitio operatorio entre pacientes sometidos a procedimientos mayores de colon y recto. DISEO: Estudio observacional retrospectivo. AJUSTE: Hospital universitario terciario en Dallas. PACIENTES: Adultos sometidos a colectomía o proctectomía entre julio de 2012 a julio de 2019. PRINCIPALES MEDIDAS DE DESENLACE: Elección de antibióticos preoperatorios e infección del sitio operatorio. RESULTADOS: Entre los 2198 pacientes incluidos en el estudio, el 12,26% (n = 307) informó alergia a la penicilina. Los pacientes con alergia a la penicilina tenían más probabilidades de ser blancos (82%) y mujeres (54%) ( p < 0,01). El tipo más común de reacción alérgica notificada fue erupción cutánea (36,5%), mientras que el 7,2% de los pacientes notificó anafilaxia. Los pacientes con alergia a la penicilina autoinformada tenían menos probabilidades de recibir antibióticos betalactámicos en comparación con los pacientes que no informaron alergia a la penicilina (79,8% frente a 96,7%, p < 0,001). En general, hubo 143 (6,5%) pacientes con infecciones del sitio operatorio. En la regresión logística multivariable no hubo diferencias en las tasas de infección del sitio operatorio entre los pacientes con alergia a la penicilina frente a los que no tenían alergia a la penicilina (razón de probabilidades ajustada 1,14; intervalo de confianza del 95%, 0,71-1,82). LIMITACIONES: Diseño de estudio retrospectivo. CONCLUSIONES: La alergia a la penicilina autoinformada entre los pacientes de cirugía colorrectal es común, sin embargo, solo un pequeño número de estos pacientes informan reacciones adversas graves. Los pacientes con alergia a la penicilina autoinformada tienen menos probabilidades de recibir antibióticos betalactámicos y más probabilidades de recibir antibióticos no betalactámicos. Sin embargo, esto no afecta la tasa de infección del sitio quirúrgico entre estos pacientes y se les puede recetar de forma segura con antibióticos no betalactámicos sin afectar negativamente las tasas de infección del sitio quirúrgico. Consulte Video Resumen en http://links.lww.com/DCR/B838 . (Traducción-Dr. Juan Carlos Reyes ).

Perfusion Assessment in Left-Sided/Low Anterior Resection (PILLAR III): A Randomized, Controlled, Parallel, Multicenter Study Assessing Perfusion Outcomes With PINPOINT Near-Infrared Fluorescence Imaging in Low Anterior Resection.

BACKGROUND: Indocyanine green fluoroscopy has been shown to improve anastomotic leak rates in early phase trials. OBJECTIVE: We hypothesized that the use of fluoroscopy to ensure anastomotic perfusion may decrease anastomotic leak after low anterior resection. DESIGN: We performed a 1:1 randomized controlled parallel study. Recruitment of 450 to 1000 patients was planned over 2 years. SETTINGS: This was a multicenter trial. PATIENTS: Included patients were those undergoing resection defined as anastomosis within 10 cm of the anal verge. INTERVENTION: Patients underwent standard evaluation of tissue perfusion versus standard in conjunction with perfusion evaluation using indocyanine green fluoroscopy. MAIN OUTCOME MEASURES: Primary outcome was anastomotic leak, with secondary outcomes of perfusion assessment and the rate of postoperative abscess requiring intervention. RESULTS: This study was concluded early because of decreasing accrual rates. A total of 25 centers recruited 347 patients, of whom 178 were randomly assigned to perfusion and 169 to standard. The groups had comparable tumor-specific and patient-specific demographics. Neoadjuvant chemoradiation was performed in 63.5% of perfusion and 65.7% of standard (p > 0.05). Mean level of anastomosis was 5.2 ± 3.1 cm in perfusion compared with 5.2 ± 3.3 cm in standard (p > 0.05). Sufficient visualization of perfusion was reported in 95.4% of patients in the perfusion group. Postoperative abscess requiring surgical management was reported in 5.7% of perfusion and 4.2% of standard (p = 0.75). Anastomotic leak was reported in 9.0% of perfusion compared with 9.6% of standard (p = 0.37). On multivariate regression analysis, there was no difference in anastomotic leak rates between perfusion and standard (OR = 0.845 (95% CI, 0.375-1.905); p = 0.34). LIMITATIONS: The predetermined sample size to adequately reduce the risk of type II error was not achieved. CONCLUSIONS: Successful visualization of perfusion can be achieved with indocyanine green fluoroscopy. However, no difference in anastomotic leak rates was observed between patients who underwent perfusion assessment versus standard surgical technique. In experienced hands, the addition of routine indocyanine green fluoroscopy to standard practice adds no evident clinical benefit. See Video Abstract at http://links.lww.com/DCR/B560. VALORACIN DE LA IRRIGACIN DE LADO IZQUIERDO/RESECCIN ANTERIOR BAJA PILAR III UN ESTUDIO ALEATORIZADO, CONTROLADO, PARALELO Y MULTICNTRICO QUE EVALA LOS RESULTADOS DE LA IRRIGACIN CON PINPOINT IMGENES DE FLUORESCENCIA CERCANA AL INFRARROJO EN LA RESECCIN ANTERIOR BAJA: ANTECEDENTES:Se ha demostrado que la fluoroscopia con verde de indocianina mejora las tasas de fuga anastomótica en ensayos en fases iniciales.OBJETIVO:Nuestra hipótesis es que la utilización de fluoroscopia para asegurar la irrigación anastomótica puede disminuir la fuga anastomótica luego de una resección anterior baja.DISEÑO:Realizamos un estudio paralelo, controlado, aleatorizado 1:1. Se planificó el reclutamiento de 450-1000 pacientes durante 2 años.AMBITO:Multicéntrico.PACIENTES:Pacientes sometidos a resección definida como una anastomosis dentro de los 10cm del margen anal.INTERVENCIÓN:Pacientes que se sometieron a la evaluación estándar de la irrigación tisular contra la estándar en conjunto con la valoración de la irrigación mediante fluoroscopia con verde indocianina.PRINCIPALES VARIABLES EVALUADAS:El principal resultado fue la fuga anastomótica, y los resultados secundarios fueron la evaluación de la perfusión y la tasa de absceso posoperatorio que requirió intervención.RESULTADOS:Este estudio se cerró anticipadamente debido a la disminución de las tasas de acumulación. Un total de 25 centros reclutaron a 347 pacientes, de los cuales 178 fueron, de manera aleatoria, asignados a perfusión y 169 a estándar. Los grupos tenían datos demográficos específicos del tumor y del paciente similares. Recibieron quimio-radioterapia neoadyuvante el 63,5% de la perfusión y el 65,7% del estándar (p> 0,05). La anastomosis estuvo en un nivel promedio de 5,2 + 3,1 cm en perfusión en comparación con 5,2 + 3,3 cm en estándar (p> 0,05). Se reportó una visualización suficiente de la perfusión en el 95,4% de los pacientes del grupo de perfusión. El absceso posoperatorio que requirió tratamiento quirúrgico fue de 5,7% de los perfusion y en el 4,2% del estándar (p = 0,75). Se informó fuga anastomótica en el 9,0% de la perfusión en comparación con el 9,6% del estándar (p = 0,37). En el análisis de regresión multivariante, no hubo diferencias en las tasas de fuga anastomótica entre la perfusión y el estándar (OR 0,845; IC del 95% (0,375; 1,905); p = 0,34).LIMITACIONES:No se logró el tamaño de muestra predeterminado para reducir satisfactoriamente el riesgo de error tipo II.CONCLUSIÓN:Se puede obtener una visualización adecuada de la perfusión con ICG-F. Sin embargo, no se observaron diferencias en las tasas de fuga anastomótica entre los pacientes que se sometieron a evaluación de la perfusión versus la técnica quirúrgica estándar. En manos expertas, agregar ICG-F a la rutina de la práctica estándar no agrega ningún beneficio clínico evidente. Consulte Video Resumen en http://links.lww.com/DCR/B560. (Traducción-Dr Juan Antonio Villanueva-Herrero).