Transanal Endoscopic Microsurgery for T1 Rectal Cancer in a High-Risk Patient
The case of a 79-year-old woman with early rectal cancer on the posterior wall of the rectum is presented. The patient was placed in lithotomy position and transanal endoscopic microsurgery was performed. Full-thickness tumor excision was performed. The defect was closed with a running 3/0 suture.
1. Patient preparation: A 79-year-old female patient (ASA III) has been diagnosed with a 2-cm posterior rectal lesion located 7 cm from the anal verge. Histopathology showed well-differentiated adenocarcinoma. Whole-body computed tomography scan did not show any metastatic disease and dedicated rectal magnetic resonance imaging showed a T1N0 cancer. After the risks of possible radical surgery were explained and a multidisciplinary team discussion, the patient chose transanal endoscopic microsurgery. Bowel preparation with polyethylene glycol and venous thromboembolism prophylaxis on the day before surgery was recommended. The patient received antibiotic prophylaxis before surgery (500 mg of metronidazole and 2 g of cefuroxime).
2. Patient position: The patient was placed in lithotomy position. Before the procedure, we recommend performing the rigid sigmoidoscopy to identify the exact location of the tumor. It is very important that the tumor should always be on the posterior side: for a posterior lesion, the patient is placed in the lithotomy position, and if the lesion is laterally located, the patient is placed in the appropriate lateral decubitus position. If the tumor is on the anterior wall, the patient is placed in prone jackknife position.
3. Critical steps: If the tumor is located in the anal canal, or the tumor is more than 12 cm from the anal verge, it is very hard to reach it, although the literature shows the ability to reach tumors located up to 20 cm in the rectum. If cancer is suspected, full-thickness excision is recommended; if the lesion is benign, partial-thickness excision is enough. Yellow tissue is the mesorectum; this is a mark showing that you have removed all the layers of the bowel wall. We fix the specimen with the pins orientating it according to the bowel wall.
4. Technical pearls/tips: Clear margins are identified by marking dots (for cancer it should be 10 mm; for benign lesion, 5 mm). Then, we recommend starting the dissection at the right posterior angle. Dissection of the superior margin of the tumor can be difficult because of the restricted view; in such cases, dissection can be commenced from one marking dot to another, reducing the risk of leaving tumor behind. Full-thickness or partial-thickness dissection should be performed. It is worth mentioning that excessive tumor manipulation should be avoided. We recommend gentle manipulation to avoid disrupting the specimen or spreading tumor cells. For suturing the defect, we use 10 cm of 3/0 Vicryl suture with silver clips on both sides. Suturing might sometimes be tricky, so one should avoid dropping the needle; it will prolong the duration of the procedure. Before starting the suturing, the rectal pressure should be minimized (to approximately 10 cm H20), to avoid distention and tension of the suture line. The needle holder is constructed to position the needle correctly. If you want to correct the angle, try pulling the suture. Start with placing the first stitch at the right angle, the second suture goes from the distal edge of the wound from inside of the rectum to the outside. Also, try to grab the mesorectum (this decreases the empty space), then the proximal edge is sutured from outside to inside. The same steps are repeated while suturing. The suture is placed under tension and fixed with the aid of silver clips. While some of instruments are angled, which protects from external collision, internal collisions are still possible. We suggest using 2 instruments at 1 time with them placed to the most distant trocars. If a third instrument is needed (suction device), just leave it in a tube. We use pins to fix the specimen orientated according to the bowel wall.
5. Potential areas for injury/complication: A very important pitfall is entering the peritoneal cavity. It is not a complication, but the peritoneum has to be sutured securely. If the tumor is lower, and the peritoneum was not entered, the wound can be left open. If the tumor is on the anterior wall of the vagina (in women) or the urethra (in men), these sites can be injured if dissection is performed too deeply. For large wound defects, multiple sutures of short length should be used. When closure is complete, the rectal lumen should be inspected.