Extralevator abdominoperineal resection in the prone position.

The Miles operation is every day more in the limelight. The abdominoperineal resection compared to anterior resection results in increased rate of circumferential resection margin (CRM) infiltration, increased iatrogenic tumor perforation rate and poorer quality of the mesorectum. These worse results may be caused by excessive dissection between the distal mesorectum and the plane of the levator ani and the consequent "resection waist" or "cone" effect in the specimen. A wider excision of the pelvic floor muscles, known as extraelevator abdominoperineal resection (ELAPE), would provide a "cylindrical" specimen which would hypothetically reduce the risk of tumor perforation and CRM infiltration and local recurrence rate. However, there is insufficient evidence to conclude that the ELAPE is oncologically superior compared to standard abdominoperineal resection. Independently from the surgical technique adopted, another actual point of discussion is the position of the patient during the perineal part of the operation. The position on "prone" provides excellent pelvic exposure, a top-down dissection under direct vision and is very comfortable for the operating surgeons. However, there is no clear scientific evidence of the superiority of prone ELAPE over supine ELAPE in terms of oncologic results, morbidity and mortality. The laparoscopy seems to be the best surgical approach for the abdominal part of the operation, although it has not been validated so far by large prospective studies. Prospective, controlled and randomized trials are necessary to resolve all these issues. The current interest in a more accurate and standardized perineal surgery to obtain a cylindrical specimen, undoubtedly, will improve results.

Amputación abdominoperineal extraelevadora en posición prono / Extralevator abdominoperineal escision in the prone position

La operación de Miles ha tomado, en la actualidad, más protagonismo que nunca. Hay numerosa evidencia del incremento significativo de la tasa de afectación del margen de resección circunferencial, de la tasa de perforación tumoral iatrogénica y de la peor calidad del mesorrecto en la amputación abdominoperineal en comparación con la resección anterior. Estos peores resultados parece que se deben al denominado efecto «cintura» o «cono» originado por la disección excesiva entre el mesorrecto distal y el plano de los elevadores del ano. Una escisión más amplia de la musculatura del suelo pélvico junto al recto, conocida como amputación abdominoperineal extraelevadora, permitiría obtener una pieza «cilíndrica», lo cual disminuiría el riesgo de perforación tumoral y de margen de resección circunferencial afecto, y así la recidiva local. Sin embargo, no hay suficiente evidencia científica para concluir que con la amputación abdominoperineal extraelevadora disminuyan de forma significativa, al compararla con la amputación abdominoperineal convencional. Independientemente del concepto de la amputación abdominoperineal extraelevadora, está la cuestión de la posición del paciente. La posición en «prono» permite una exposición pélvica excelente, una disección de arriba hacia abajo con visión directa y es muy cómoda; sin embargo, tampoco hay evidencia científica clara sobre la superioridad oncológica ni en cuanto a morbimortalidad de la amputación abdominoperineal extraelevadora en prono sobre el supino. El abordaje laparoscópico, aunque todavía no está formalmente validado, parece ser el abordaje de elección, sobre todo si tenemos en cuenta que la parte oncológica y más importante de la operación se realiza por vía perineal. Serán necesarios nuevos estudios prospectivos, controlados y aleatorizados para poder resolver estas cuestiones; sin embargo, el interés actual en una cirugía perineal más precisa y estandarizada con el objetivo principal de un espécimen cilíndrico, sin lugar a dudas, mejorará los resultados

The Miles operation is every day more in the limelight. The abdominoperineal escision compared to anterior resection results in increased rate of circumferential resection margin (CRM) infiltration, increased iatrogenic tumor perforation rate and poorer quality of the mesorectum. These worse results may be caused by excessive dissection between the distal mesorectum and the plane of the levator ani and the consequent «waist» or «cone» effect in the specimen. A wider excision of the pelvic floor muscles, known as extraelevator abdominoperineal escision (ELAPE), would provide a «cylindrical» specimen which would hypothetically reduce the risk of tumor perforation and CRM infiltration and local recurrence rate. However, there is insufficient evidence to conclude that the ELAPE is oncologically superior compared to standard abdominoperineal escision. Independently from the surgical technique adopted, another actual point of discussion is the position of the patient during the perineal part of the operation. The position on «prone» provides excellent pelvic exposure, a top-down dissection under direct vision and is very comfortable for the operating surgeons. However, there is no clear scientific evidence of the superiority of prone ELAPE over supine ELAPE in terms of oncologic results, morbidity and mortality. The laparoscopy seems to be the best surgical approach for the abdominal part of the operation, although it has not been validated so far by large prospective studies. Prospective, controlled and randomized trials are necessary to resolve all these issues. The current interest in a more accurate and standardized perineal surgery to obtain a cylindrical specimen, undoubtedly, will improve results