Background: Proctocolectomy with ileal reservoir is the surgical procedure of choice for patients with ulcerative colitis and familial adenomatous polyposis.

Objective: To evaluate long-term postoperative complications (1994-2019) in patients operated for familial adenomatous polyposis (FAP) and ulcerative colitis (UC) and the degree of satisfaction with the procedure.

Methods: Observational study based on the analysis of a retrospective database with prospective follow-up in 115 consecutive patients: 79 with UC and 36 with FAP. A total of 88 patients were followed up, 60 with UC and 28 with PFA.

Results: 48 males (54.4%) with a mean age of 44.8 ± 10.6 years were evaluated. Indications for surgery were intractable disease in 54 patients (47%), dysplasia/cancer in 43 (37%), severe bleeding in 4 (4%) and perforation in 3 (3%). A proctectomy and mucosectomy of the rectal stump was performed in 67 (76.1%), and a double stapling technique in 21. A protective ileostomy was performed in all patients with UC and FAP. No differences were found in early complications between the two groups. Late complications showed a higher rate of reservoritis in UC patients compared to FAP (44.9 vs. 14.3%, p = 0.001), with more refractory reservoritis in the UC group (13.3 vs. 0%, p = 0.04) with no differences in bowel obstruction, strictures, or anastomotic fistulas. Overall satisfaction and adaptation were considered good in 87% of UC patients and only 57% in the FAP group (p < 0.01).

Conclusions: Proctocolectomy with ileal reservoir has comparable morbidity and mortality, except for the higher rate of reservoritis in patients with a history of UC, despite this contingency there is a better quality of life and greater acceptance of surgery in UC patients than in FAP patients.