Abdominoperineal resection (APR), also known as abdominoperineal excision of the rectum (APER), is a surgical treatment predominantly indicated for low rectal cancer and involves resection of the rectum and anal canal, leaving a permanent colostomy.

Indications

• low rectal cancer ⁷

  • within 5 cm of the anal verge

  • with involvement of the external anal sphincter / levator ani

  • with characteristics preventing a negative distal resection margin

• anal squamous cell carcinoma ⁷

• rectal dysplasia in patients with inflammatory bowel disease ⁷

Procedure

There are two stages to the operation ^2,7:

• abdominal stage: distal sigmoid colon mobilisation, dissection of the inferior and superior rectal arteries, dissection along the total mesorectal plane with mobilisation of the rectum to the level of the levator ani, colon divided and colostomy formed, abdominal closure

• perineal stage: suturing of the anus, dissection of the anal canal can be intersphinteric, extrasphincteric (standard appoach), or extralevator) to the levator ani to meet the abdominal dissection to completely mobilise the rectum with subsequent extraction

Although historically performed as an open procedure, the abdominal stage can be performed laparoscopically or robotically ^5,7.

Complications

General complications associated with major abdominal surgery include intra-abdominal abscess, ileus, small bowel obstruction, iatrogenic injury, or stoma complications e.g. ischaemia, prolapse, parastomal hernia ^ref.

Perineal complications such as delayed wound healing or dehiscence are specific to this procedure as it involves a perineal step that other colorectal procedures do not ^ref.

Radiographic appearances

These imaging appearances are described here for the normal postoperative status without complication or recurrent disease process.

Plain radiograph

Absence of gas pattern of the sigmoid, rectum and anal canal with visualisation of surgical metallic clips, though an anastomotic staple line will not be visible as might be expected after an anterior resection ^ref.

CT

Sigmoid colon, rectum and anal canal will be absent along with presence of permanent colostomy in left iliac fossa. The rest of the pelvic organs may be displaced and occupying the post-surgical space.

A degree of presacral soft tissue thickening is a common postoperative finding as a result of the filling the APR cavity and this can be difficult to differentiate from local recurrent disease as it may persist for a long time ⁵. PET-CT can be used to differentiate this normal finding from recurrent disease ⁶.

History and etymology

First described in 1908 by William Ernest Miles (1869–1947), an English surgeon ⁴, as a result, it is also rarely known as the Miles procedure ⁵.