Laparoscopic Abdominoperineal Resection - Dr. R.K. Mishra

Laparoscopic Abdominoperineal Resection

Laparoscopic abdominoperineal resection is an operation in which the anus, rectum, and sigmoid colon are removed. It is used to treat cancer located very low in the rectum or in the anus, close to the sphincter muscles. Laparoscopic surgery for anorectal carcinoma is steadily gaining acceptance. The advantage offered by laparoscopy has always centered on improved vision. This advantage seems to be put to best use in the case of rectal cancer surgery, where logistic impediments, viz. narrow pelvis and impaired visibility as the dissection proceeds caudad, have proved to be obstacles to colorectal surgeons during open surgery. Recent studies have shown that the size of the tumor does not hamper the feasibility of performing laparoscopic abdominoperineal resection. We need to consider the possibility of an increased circumferential margin rate for large-size tumors. This may be addressed by preoperative radiotherapy and chemotherapy before undertaking surgery on these large tumors. It is important to note, though, that the oncological safety is not only dependant on the abdominal procedure but also on the adequacy of the perineal part of the operation. Besides, should tumor injury be detected intraoperatively, it is advisable to convert to open surgery to control the amount of contamination and complete the rest of the procedure.

Anus, rectum, and sigmoid colon removed in APR
 Anus, rectum, and sigmoid colon removed in APR

Patient Position

The patient is placed supine on the operating table on a beanbag. After induction of general anesthesia and insertion of an orogastric tube and Foley catheter, the legs are placed stirrups. The arms are tucked at the patient's side. The abdomen is prepared with an antiseptic solution and draped routinely.

Position of Surgical Team

The primary monitor is placed on the left side of the patient up toward the patient's feet. The secondary monitor is placed on the right side of the patient at the same level and is primarily for the assistant during the early phase of the surgery and port insertion. The operating nurse's instrument table is placed between the patient's legs. There should be sufficient space to allow the surgeon to move from either side of the patient to between the patient's legs, if necessary. The primary operating surgeon stands on the right side of the patient with the assistant standing on the patient's left and moving to the right side, caudad to the surgeon, once ports have been inserted.

Port Position

This is performed using a Hasson approach. A 10 mm smiling sub umbilical incision is made. This is deepened down to the linea alba, which is then grasped on each side of the midline using Kocher clamps. A scalpel (No. 15 blade) is used to open the fascia between the Kocher clamps and a Kelly forceps is used to open the peritoneum bluntly. Having confirmed entry into the peritoneal cavity, a purse-string suture of 0 polyglycolic acids is placed around the sub umbilical fascial defect. A 10 mm reusable port is inserted through this port wound allowing the abdomen to be insufflated with CO2 to a pressure of 12 mm Hg. The laparoscope is inserted into the abdomen and an initial laparoscopy is performed, carefully evaluating the liver, small bowel, and peritoneal surfaces. A 12 mm port is inserted in the right lower quadrant approximately 2 to 3 cm medial and superior to the anterior superior iliac spine. This is carefully inserted lateral to the inferior epigastric vessels, paying attention to keep the tract of the port going as perpendicular as possible through the abdominal wall. A 5 mm port is then inserted in the right upper quadrant at least a hand's breadth superior to the lower quadrant port. A left lower quadrant 5 mm port is also inserted.

Exposure and Dissection of Retroperitoneum

The assistant now moves to the patient's left side, standing caudad to the surgeon. The patient is rotated with the left side up and right side down, to approximately 15 to 20 degrees tilt, and often as far as the table can go. This helps to move the small bowel over to the right side of the abdomen. The patient is then placed in the Trendelenburg position. This again helps gravitational migration of the small bowel away from the operative field. The surgeon then inserts two atraumatic bowel clamps through the two right-sided abdominal ports. The greater omentum is reflected over the transverse colon so that it comes to lie on the stomach. If there is no space in the upper part of the abdomen, one must confirm that the orogastric tube is adequately decompressing the stomach. The small bowel is moved to the patient's right side allowing visualization of the medial aspect of the rectosigmoid mesentery pedicle. This may necessitate the use of the assistant's 5 mm atraumatic bowel clamp through the left lower quadrant to tent the sigmoid mesentery cephalad. Complete mobilization of the left colon is not required. Adequate mobilization must allow the formation of a left iliac fossa colostomy without tension. Following the division of the inferior mesenteric artery, the left mesocolon is separated from the retroperitoneum in a medial-to-lateral direction using a spreading movement. An atraumatic bowel clamp inserted through a right-sided port is placed under the left colonic mesentery, which is elevated away from the retroperitoneum, and using scissors inserted through the other right-sided port, the attachments to the retroperitoneum are swept down, until the lateral abdominal wall is reached.

Division of the Left Colon

The mesentery of the left colon is divided from the free edge, cranial to the previously divided inferior mesenteric artery, toward the left sigmoid colon. The mesentery can be divided with diathermy and the marginal artery can be clipped and then divided. Alternatively, an energy source such as a LigaSure may be used to divide the mesentery up to the edge of the bowel. This may be done before freeing the lateral attachments of the sigmoid and left colon as it aids in retraction. After the division of the mesentery, the lateral attachments of the sigmoid to the abdominal wall are divided along the white line. Care is taken to avoid damage to the retroperitoneal structures. The colon is then divided using a linear endoscopic stapler at the site where the colonic mesentery has been divided.

Rectal Mobilization

In women, the uterus may be hitched out of the area of dissection with a suture. Atraumatic bowel clamps that are inserted through the left-sided ports are used to elevate the rectosigmoid colon out of the pelvis and away from the retroperitoneum and sacral promontory, to enable entry into the presacral space. The posterior aspect of the mesorectum can be identified and the mesorectal plane dissected with diathermy, preserving the hypogastric nerves passing down into the pelvis anterior to the sacrum. Dissection continues down the presacral space in this avascular plane toward the pelvic floor. Attention is now switched to the peritoneum on the right side of the rectum. This is divided to the level of the seminal vesicles or rectovaginal septum. This is repeated on the peritoneum on the left side of the rectum. This facilitates further posterior dissection along the back of the mesorectum to the pelvic floor, to a level inferior to the lower edge of the mesorectum. Usually, when the approach is low on the posterior surface of the mesorectum, it becomes necessary to perform a lateral and anterior dissection. A bowel grasper inserted through the left iliac fossa port is used to retract the peritoneum anterior to the rectum forward. The peritoneal dissection is continued from the free edge of the lateral peritoneal dissection, anteriorly. Lateral dissection is continued on both sides of the rectum and is extended anteriorly to the rectum in front of Denonvillier's fascia, separating the posterior vaginal wall from the anterior wall of the rectum or down past the level of the prostate in men. The most inferior rectal dissection can be completed from the perineal approach. For anterior tumors, the dissection may be performed anterior to Denonvillier's fascia, or by taking one side of the fascia to protect the anterolateral nerve bundle. It is necessary to perform a total mesorectal excision and hence the rectum must be dissected down close to the muscle tube of the rectum below the level of the mesorectum. The levators may then be divided from above, staying well wide of any potential tumor, or the division may be performed from below after making the perineal incision.

Formation of Trephine Left Iliac Fossa Colostomy

The divided distal end of the left sigmoid colon is grasped with atraumatic bowel clamps, which are locked. A trephine colostomy is made in the left iliac fossa at a site that has been marked by an enterostomal therapist before surgery. A skin disk is excised, and a longitudinal incision is made in the anterior rectus sheath and the left rectus muscle is split. The peritoneum is held with two hemostats and incised. The stapled colon is delivered to the trephine and grasped with Babcock forceps and delivered through the trephine. The staple line is excised and the end colostomy is matured using 3/0 chromic catgut sutures.

Perineal Dissection

The perineal dissection is performed with a conventional open approach. The anus is sutured closed with 0 nylon and an elliptical skin incision is made. The incision is deepened using diathermy and the ischiorectal fossae are entered on either side, well lateral to the external sphincter muscle. The dissection continues laterally and posteriorly to expose the levator ani muscles. The tip of the coccyx is used as the posterior landmark and the pelvic cavity is entered by dividing the levator ani muscle just anterior to the tip of the coccyx. A finger can be placed into the pelvis onto the upper border of the levator ani, which is divided with diathermy onto the underlying finger. Care is taken anteriorly to divide the remaining levator ani while protecting the posterior surface of the vagina or prostate/ urethra. The specimen may then be delivered out of the pelvis, which facilitates the division of the remaining anterior attachments of the rectum, reducing the risk of damage to the prostate or posterior wall of the vagina. The specimen is removed, the pelvic cavity irrigated of blood or debris, and the perineal tissue closed in layers using polydioxanone sutures.

Perineal dissection
  Perineal dissection

 Perineal anatomy
 Perineal anatomy

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