What are the operative steps in an anterior resection?

Operative Steps in Anterior Resection

Anterior resection for rectal cancer involves full rectal mobilization to the levator ani muscles, mesorectal excision in the appropriate plane, vascular ligation, bowel division with adequate margins, and reanastomosis to peritonealized distal rectum or below the peritoneal reflection. 1, 2

Patient Positioning and Access

• Position the patient supine with appropriate padding and access to the abdomen 3
• Create adequate abdominal access through midline laparotomy or laparoscopic ports 4
• In single-access laparoscopic approaches, a 3.0-cm incision at the right iliac fossa provides port access 4

Vascular Control and Mesenteric Dissection

• The inferior mesenteric artery (IMA) is the crucial landmark for obtaining the correct dissection plane 3
• Dissect the descending mesocolon using a medial approach 4
• Skeletonize the IMA and perform high ligation with lymph node dissection 4
• Divide the superior rectal artery during lymph node dissection 4
• Mobilize the sigmoid colon adequately for tension-free anastomosis 3

Mesorectal Excision

• Perform total mesorectal excision (TME) for mid and distal rectal cancers (tumors below 10-12 cm from anal verge) 2
• Execute partial mesorectal excision (PME) for proximal tumors when a 4-5 cm mesorectal margin can be achieved 2
• Use sharp perimesorectal dissection technique to stay in the correct plane 2
• A good light source is essential for visualizing the correct dissection planes and maintaining proper surgical planes 3
• Extend the TME dissection to the pelvic floor/levator ani muscles 1, 4
• Develop the interatrial groove and mobilize the rectum circumferentially 2

Rectal Division and Specimen Removal

• Transect the rectum below the peritoneal reflection for low tumors 4
• Ensure adequate distal margin (typically 2 cm for most rectal cancers) 2
• Remove the specimen with intact mesorectum 2

Anastomosis Construction

• Use the sigmoid colon for construction of a J-pouch whenever possible for very low anastomoses 3
• Perform either hand-sewn (traditional) or stapled anastomosis 1
• The double-stapling technique is commonly employed for low anastomoses 4
• Reanastomose to peritonealized distal rectum or below the peritoneal reflection depending on tumor level 1
• Consider defunctioning ileostomy for very low anastomoses, though not universally required 4

Adjunctive Procedures

• Mobilize the omentum as a pedicle graft based on the left gastro-epiploic arcade and transpose to the pelvis for retrocolic omentoplasty 5
• This adds 15-20 minutes to operative time but promotes sound healing 5

Closure and Drainage

• Place pelvic drains (typically 2 soft drains) 5
• Close the abdomen in standard fashion 1

Critical Technical Points

• TME procedures require significantly longer operating time, result in more blood loss, and carry higher anastomotic leak rates (8.1%) compared to PME (1.3%) 2
• Male gender, absence of protective stoma, TME technique, and increased blood loss are independent risk factors for anastomotic leakage 2
• Median operating time for anterior resection ranges from 175-245 minutes depending on technique 4
• Blood loss should be minimal with proper technique (1-20 mL in laparoscopic series) 4

Common Pitfalls to Avoid

• Failing to identify the IMA early leads to incorrect dissection planes 3
• Inadequate lighting prevents visualization of proper surgical planes 3
• Creating tension on the anastomosis by insufficient sigmoid mobilization increases leak risk 3
• Performing TME when PME would suffice for proximal tumors increases morbidity unnecessarily 2
• Not considering protective diversion for very low anastomoses in high-risk patients 2