Transanal Total Mesorectal Excision

Sherief Shawki

Dana Sands

Matthew F. Kalady

Perioperative Considerations

Preoperative Setting: Rectal Cancer Patients

Examination
- Digital rectal examination
- Flexible and/or rigid proctoscopy
- Sphincter evaluation
Clinical tumor staging
- Local staging: pelvic magnetic resonance imaging
  - Particular note of the relation of tumor to the surrounding structures and the angle between the anal canal and the levator ani to estimate the direction of mesorectum once passed the puborectalis posteriorly.
  - This will help avoiding dissecting in the false areolar plan along the wall of the rectum.
  - Evaluation for circumferential resection margin
- Distant radiologic staging
  - Chest and abdomen computed tomography
  - Additional imaging based on concern for metastatic disease
- Serum carcinoembryonic antigen
Multidisciplinary tumor board discussion and treatment plan recommendations
Stoma marking and education
Mechanical and oral antibiotic bowel preparation

Anesthesia

General anesthesia
Deep muscular blockade is required to achieve proper rectal distension and appropriate relaxation.

Patient Positioning

Modified lithotomy position with arms tucked at the side
Adjustable stirrups
Adequate padding and securing of the patient in order to support steep Trendelenburg positioning
Oral gastric tube and Foley catheter

Prior to Sterile Field Preparation

Examination under anesthesia
- Confirm location of the tumor, mobility, and predicted distal margin.
- Determine whether anastomosis will be handsewn or stapled.
- For benign pathology, confirm appropriate operative plan, re-evaluate sphincters.
Rectal enema with diluted povidone iodine is performed.

Sterile Field Preparation and Operating Room Setup

FIGURE 32-1 ▪ Room setup. Patient is in modified lithotomy position. Abdominal team is in position with the laparoscopic tower on the left side of screen and the corresponding monitor on the other side. The perineal team tower is on the right side of the screen, and corresponding monitor is by the patient’s head in front of the surgeon.

The abdominal and perineal fields are prepped and draped for two team approach (Fig. 32-1).

Instruments Needed (See Chapter 31 for the Abdominal Proctectomy Portion)

Laparoscopic instruments needed

30-degree rigid scope, 5 mm (preferred) or 10 mm

Light cord right-angle adapter (Fig. 32-2)

FIGURE 32-2 ▪ GelPOINT in place. Note the right-angle adapter with 30-degree scope to the left; thus, the camera is placed further to the right, resulting in more space for the surgeon’s hands and minimizing external collision.

Allows an improved extracorporeal space for the surgeon for external hand movements and minimizes collision with the camera

Maryland grasper/dissector
Atraumatic bowel graspers
Hook with electrocautery
Suction device

Insufflation:
- AirSeal system (SurgiQuest, CT, USA)
  - Care must be taken to avoid fluid in the tubing of the system that will result in system malfunction.
- Standard insufflation systems may also be utilized, though may result in billowing of tissues.
Access: GelPOINT access platform (Applied Medical, Rancho Santa Margarita, CA, USA) (Fig. 32-3)
- Regular size channel: 4 cm × 5.5 cm
- Long channel: 4 cm × 9 cm
Port placement in the Gel Cap (Fig. 32-4)

FIGURE 32-3 ▪ Various sizes of GelPOINT access channel. Regular: 4 cm diameter × 5.5 cm long. Long: 4 cm × 9 cm.

FIGURE 32-4 ▪ Gel Cap placed with laparoscopic ports position in reverse triangle. In this case, we used the long 8-mm AirSeal port; hence, the scope was 5 mm, 30 degrees.
- Three ports with triangulation
- Either 8- or 10-mm AirSeal ports can be used depending on the use of camera.
- AirSeal port is a working port for better smoke-suctioning function.
Initial exposure and placement of the access platform is aided by either a Lone Star retractor (Cooper Medical) or anal eversion sutures.

Purse-String Suture Placement

Placed after careful and precise evaluation of distal margin in relation to the most distal extent of the tumor, at least 1 cm distal to the distal tumor edge (Fig. 32-5).
Depending on the location of the tumor, it can be placed in standard transanal manner under direct visualization, or endoluminally in a laparoscopic manner via port instrumentation after establishing pneumorectum.
- The latter will require proximal clamping of the colon from the laparoscopic team to avoid overdistension, which can hinder the laparoscopic mobilization.

FIGURE 32-5 ▪ Defining distal margin in relation to the lowest point of the tumor.

Important Points to Consider When Performing the Purse-String Suture

Purse-string suture should be circumferential without spiraling.
- A circumferential marking using electrocautery may be used for outlining to avoid spiraling (Fig. 32-6).
  
  FIGURE 32-6 ▪ Marking for the purse string to ensure circumferential suture and avoid spiraling.
- Temporary placement of a sponge in the rectum may serve as a reference point to avoid inappropriate spiraling.
  - The sponge should be removed prior to tying the knot.
The suture should incorporate near full-thickness tissue, but caution is advised to avoid too deep of bites, especially when placed distally in the rectum (Fig. 32-7A-H).
- Anteriorly, the vaginal wall could be incorporated if the suture is placed too deeply.
- Laterally, the endopelvic fascia may be drawn inward, which could potentially direct the surgeon to the extrafascial plane upon proctotomy.
Avoid taking too much tissue with each needle pass. This will result in bunching of the mucosa after tying the purse string.
- The resultant redundancy will interfere with proper stretching upon establishing insufflation, which may render the proctotomy technically challenging.
It is also important to avoid gaps between needle passes. The inlet of each new needle pass should be just adjacent to the exit of the prior bite. Upon insufflation, this gapping may result in leaks and results in deformity of the lumen, rendering proper proctotomy difficult.

FIGURE 32-7 ▪ A-G. A sequence of endoluminal laparoscopic purse string. No gapping, deep or greedy bites.

FIGURE 32-7 ▪ (continued) H. Purse string could be completed in an open transanal manner.
Equidistant with equal depth suture passes is preferred. The depth is just under the submucosa. When done this way, upon proctotomy and traversing the muscle layer, the insufflation facilitates retraction of the muscle fibers, exposing the correct plan for the surgeon.
After the purse string is secured (Fig. 32-8), a thorough washout of the distal rectum and change of gloves is advisable prior to the proctotomy, as the bowel is now closed from the viable tumor and minimizes tumor cells shedding.