Abdominoperineal Resection (APR)
What the Examiner Expects
Combined abdominal and perineal resection of the rectum, anus, and sphincter complex with creation of a permanent end colostomy. APR is indicated when the tumor involves the anal sphincters or is too low (typically < 1–2 cm from the dentate line) to achieve an adequate distal margin with sphincter preservation. The examiner expects you to know the indications, understand that this results in a permanent stoma, and describe the technique: the abdominal portion involves sigmoid mobilization, IMA ligation, and TME dissection down to the levators; the perineal portion involves wide excision of the anus, sphincters, and levator muscles. Cylindrical (extralevator) APR takes wider perineal margins to reduce positive circumferential resection margins for bulky low tumors.
Key Examiner Focus Points
- Indicated for low rectal cancers involving the sphincter complex
- Permanent end colostomy — the rectum and anus are completely removed
- Perineal wound complications are common (dehiscence, abscess)
- Risk to autonomic nerves (hypogastric plexus) causing urinary/sexual dysfunction
- Cylindrical (extralevator) APR reduces positive CRM rates for low tumors
Common Curveballs
During the perineal dissection, you encounter significant presacral bleeding
Presacral venous plexus bleeding can be life-threatening. Direct pressure with packing. Thumbtack (sterile stainless steel) insertion into the sacrum over the bleeder is the classic technique. Bone wax can also be applied to the sacrum. Electrocautery often makes it worse by enlarging the venous defect in the presacral fascia.
Patient asks if there is any alternative to a permanent stoma
For very low rectal cancers, options include intersphincteric resection (ISR) with coloanal anastomosis if there is an adequate margin above the dentate line, or total neoadjuvant therapy with watch-and-wait protocol for clinical complete responders. These should be discussed at multidisciplinary tumor board.
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