What are the operative steps in an anterior resection?

From the Guidelines

An anterior resection involves several key operative steps, including patient positioning, abdominal access, mobilization of the sigmoid colon and rectum, ligation and division of the inferior mesenteric vessels, and restoration of bowel continuity with a colorectal anastomosis, as outlined in the NCCN clinical practice guidelines in oncology for rectal cancer 1. The procedure begins with patient positioning in modified lithotomy, followed by abdominal access via laparotomy or laparoscopy.

• Key steps include:
  • Mobilization of the sigmoid colon and rectum by dividing the lateral peritoneal attachments and entering the avascular presacral plane
  • Identification, ligation, and division of the inferior mesenteric vessels, with preservation of the hypogastric nerves
  • Mobilization down to the pelvic floor with careful dissection of the mesorectum, either partially or completely depending on tumor location
  • Transection of the rectum distal to the pathology using a linear stapler, ensuring adequate margins
  • Division of the proximal colon and removal of the specimen
  • Restoration of bowel continuity with a colorectal anastomosis, typically using a circular stapling device
  • Testing of the anastomosis integrity with air insufflation while the pelvis is filled with saline
• A diverting loop ileostomy may be created if the anastomosis is low or at high risk of leakage, as suggested by the guidelines for rectal cancer treatment 1. The procedure concludes with hemostasis, irrigation, drain placement if indicated, and closure of the abdominal incision.
• Postoperatively, patients require close monitoring for complications such as anastomotic leak, bleeding, and ileus, emphasizing the importance of a multidisciplinary approach in treating patients with colorectal cancer 1.

From the Research

Operative Steps in Anterior Resection

The operative steps in an anterior resection involve several key procedures, including:

• Patient positioning: The patient is positioned supine in lithotomy 2
• Laparoscopic access: Laparoscopic access is obtained to allow for visualization and manipulation of the surgical site 2
• Mobilization of the sigmoid and descending colon: The sigmoid and descending colon are mobilized to allow for access to the rectum 2
• Mobilization of the rectum: The rectum is mobilized in the retrorectal space to allow for resection 2
• Dissection of the sigmoid colon from the bladder: The sigmoid colon is dissected free from the bladder to prevent damage to the bladder during the procedure 2
• Intracorporeal division of the mesentery: The mesentery is divided intracorporeally to allow for resection of the specimen 2
• Testing of the bladder for leaks: The bladder is tested for leaks to ensure that there is no damage to the bladder 2
• Extraction of the specimen: The specimen is extracted, either through a minilaparotomy incision or using a transanal approach 2, 3, 4
• Performance of a stapled colorectal anastomosis: A stapled colorectal anastomosis is performed to restore continuity of the colon 2

Variations in Operative Technique

There are several variations in operative technique that have been described, including:

• Use of a double-stapling technique: This technique involves the use of two staplers to create the anastomosis, and has been shown to have an acceptable clinical leak rate, local recurrence rate, and survival rate 5
• Use of a side-to-end anastomosis: This technique involves creating a side-to-end anastomosis using the sigmoid colon, and has been shown to improve short-term bowel function in patients undergoing laparoscopic low anterior resection 6
• Use of transanal bowel reversing retrieval: This technique involves pulling the specimen out transanally and performing the anastomosis intracorporeally, and has been shown to be a safe and effective alternative to traditional minilaparotomy incision 4