This study investigates the evolution of abdominal surgery in treatment of Crohn´s disease (CD) in the era of immunomodulatory drugs and biologicals. It concerns risk of abdominal surgery overall and sub-categories of abdominal surgery, risk of repeat surgery and factors that affect this risk, and risk of getting a stoma. Surgical recurrence is a major clinical problem as repeat procedures are more complex and expose the patients to a higher medical risk both in conjunction with surgery and afterwards. Updated information on abdominal surgery for CD will be of use when making decisions about medical vs surgical interventions.

In a nationwide cohort of 21 273 patients with CD during the years 1990-2014, the cumulative incidence of abdominal surgery within five years of diagnosis decreased continuously down to 17.3% for patients diagnosed with CD during the last calendar period of study, 2009–2014. Ileocecal resection was the most common primary procedure. The incidence of colectomy was low in all calendar periods and continuously decreased. The incidence of proctectomy was very low even after decades with the disease, 3.0% for patients diagnosed 1990-1995 with a median follow-up of 21 years. Incidence of repeat abdominal surgery within five years of primary procedure decreased in the 90s down 16.0% in the 1996– 2000 period with a risk of ileocolic reresection of 4.4%. After 2000, despite introduction of biologicals in 1998, no further significant decrease in repeat surgery was observed.

In a retrospective review of prospectively maintained databases at three university hospitals, the rate of surgical recurrence for 389 patients with CD who had been treated with a primary ileocecal resection between 2000-2012 was investigated. The patients were operated receiving either a temporary stoma (20%) or a primary anastomosis (80%) with a median follow-up time of 105 months. Patients selected to temporary stoma had a higher prevalence of baseline risk factors usually associated with an increased risk of recurrence such as penetrating disease behaviour. Despite this, there was no difference in long-term surgical recurrence between the one- and two-stage groups; 18% vs 16%.

In a retrospective review of prospectively maintained databases at two university hospitals, the effect of smoking cessation on rate of surgical recurrence was assessed. 242 patients were included with a median follow-up of 112 months. Surgical recurrence rate for smokers vs quitters was 16/42 (38%) vs 3/31 (10%); p = 0.02; risk ratio = 3.9 despite a median time for smoking exposure after the primary procedure of three years. Among the non-smokers 28/169 (17%) had a surgical recurrence at last follow-up. 8 out of 11 smoking patients who needed a second resection went on to need a third resection. Of the patients who were free of surgical recurrence at follow-up, those who had quit smoking were significantly less likely to have been put on medical therapy compared with smokers with a risk ratio of 3.2.

In an observational study of a nationwide cohort of 19 146 patients with incident CD 2002- 2013 and followed through 2017, the incidence and prevalence of stoma was investigated. The cumulative incidence of stoma formation within five years was 2.4% and remained constant from 2002 and onwards although cumulative ever-use of biologicals increased and time to start with treatment with biologicals decreased. 48% of all stomas were reversed. Ileostomies encompassed about two-thirds of all stomas and risk of stoma was higher among patients with elderly-onset CD and among patients with perianal manifestations of the disease. 28% of the patients who underwent surgery with formation of a stoma had perianal disease. 0.6% of all incident patients had a permanent stoma five years after diagnosis.