Retained Rectum in a Patient Status Post Total Proctocolectomy for Ileocolonic Crohn’s Disease

Abstract

A 28-year-old female with a twenty-year history of penetrating ileocolonic Crohn’s disease status post total proctocolectomy (TPC) presented to the inflammatory bowel disease clinic with 4 months of a draining perianal abscess. The discharge was serosanguineous mixed with mucoid tissue soiling 5 feminine pads daily. Three years prior to presentation she had an emergent subtotal colectomy with ileostomy for a colonic perforation while on adalimumab. Subsequent to her surgery, adalimumab was discontinued and she was maintained in clinical remission on mesalamine and azathioprine. One year later, a necrotic rectal stump precluded an attempt to restore continuity and underwent completion proctectomy through a perineal approach and maintained her permanent ileostomy. She remained on mesalamine and azathioprine with stable ostomy output and without any gastrointestinal symptoms until her current presentation. Her exam was significant for a 3 cm midline draining open wound at the level of her prior anus with surrounding erythema but no fluctuance. The site was exquisitely tender to palpation and blood mixed with pus was easily expressed. CT and magnetic resonance imaging of the pelvis revealed a perianal fistula communicating with a hyperintense lesion within the presacral fat and posterior to the uterus measuring 16 × 19 × 26 mm suggestive of a remnant rectal pouch. Additionally, there was evidence of a fistulous track from the rectal remnant to the perineum and a rectovaginal fistula. Initial therapy with oral metronidazole improved her perineal pain and drainage. She underwent a redo abdominoperineal resection where the remnant rectum was identified and completely resected. A rectovaginal fistula was identified in the posterior vaginal wall and excised. The histopathology of the specimen was significant for colonic tissue with chronic active colitis and transmural inflammation. After surgical excision of the active diseased colonic remnant tissue her fistulas healed and her perineal pain ceased. This is an unusual case of an unintentionally retained rectum in a patient status post proctocolectomy presenting as active perianal Crohn’s disease. Approximately 75% of all CD patients will require surgery during their lifetime, which can include a total colectomy in medically refractory Crohn’s colitis. Patients with rectal and perianal involvement of Crohn’s undergo TPC and end ileostomy given the high rates of complications in the excluded rectal stump. In patients with acute complications from Crohn’s colitis requiring urgent colonic resections, TPC is typically done in a two-step fashion, as was the intent with this patient. Routinely, due to the length of remaining distal rectum within the pelvic floor, an open abdominal approach is required to assure all colonic tissue is excised. The surgical perineal approach to removing the distal segment in this patient underestimated the length of the remaining colon within the pelvis leading to the retained rectum. Having completely removed the anal canal with adjacent rectal tissue and the proximal colon in the initial surgery, the patient was left with a “floating” segment of rectum within the pelvic floor, which maintained active CD. This case illustrates an unusual surgical complication of a completion proctectomy in Crohn’s.