Abdominal perineal resection (APR) of the rectum and sigmoid is used for the removal of rectal cancer that has invaded the anal sphincter mechanism or is too close to the anal canal or too large to perform a sphincter-sparing resection or low anterior resection (LAR) (see Chapter 52). Most patients with rectal cancer who require an APR will also undergo neoadjuvant therapy with chemotherapy and radiation to the pelvis. This causes a special problem with healing in the perineal incision but not with the abdominal portion of the procedure. Preoperative radiation to the pelvis involves the sigmoid colon as well as the rectum, and therefore the sigmoid colon should be removed routinely with the rectum and anus. By definition, a permanent colostomy is the end result of an APR.
The most important aspect of preparing a patient for an APR is consultation with an enterostomal therapist to educate, support, and select the best stoma site for the permanent colostomy. As with a LAR, a mechanical bowel prep and IV antibiotics are usually recommended to reduce pelvic, perineal, and skin infections. The site most at risk for a complication is the perineal wound after closure. The rest of the preoperative measures, including deep venous thrombosis (DVT) prophylaxis, are the same as for LAR.
Because the patient will have no large abdominal wound, the risk of postoperative pneumonia and respiratory failure is not generally as great as with open surgery. However, supplemental epidural pain management may be of use due to intense perineal pain. Ketorolac is also useful to reduce the need for parenteral narcotic use (patient-controlled analgesia, PCA).
The abdominal portion of the procedure is performed with the patient in lithotomy position with sequential devices in place and Allen stirrups. The patient is fixed in position with a beanbag, and both arms are tucked. Thigh flexure is less than 10 degrees, and knee flexure is near 90 degrees (Figure 1). The perineal portion of the APR can be performed in this position with the surgeon standing between the patient’s legs with the table raised to maximum height. Alternatively, the prone flexed position with the hips supported on a roll, rolls under the chest and axillae, and the buttocks taped apart can provide increased access to the pelvis.
For the abdominal portion of the operation, the monitors, surgeon, assistant, and camera operator are placed in the same positions as for a LAR. The table is positioned in steep Trendelenburg and tilted to the right for the majority of the procedure until the rectum is dissected from the pelvis. During the rectal dissection the table is placed in Trendelenburg position.