["In spite of the important role of conservative treatment, up to 90 % of all patients with Crohn's disease will undergo an operation during the course of their illness. Up to 50 % even need a second operation or further surgical procedures - with an increasing risk for perioperative complications. This study was designed to identify the risk factors for recurrence in patients with Crohn's disease and the influence of the primary operation.", 'Between 1986 and 2004, 412 patients with Crohn\'s disease required operative treatment. 218 underwent a primary procedure and 194 needed a reoperation. In particular, the indications for surgical treatment, the surgical procedures and the perioperative complications were registered and evaluated in the context of a possible recurrence of Crohn\'s disease. In this study, "recurrence" is defined as a reoperation because of Crohn\'s disease after a primary operation.', "The most common indications for a surgical treatment were stenosis (58.4 %) and fistulas (38.5 %). As the most frequent procedures, the ileocoecal resection and the partial resection of the small bowel were performed. Altogether, the complication rate was 11.5 %. The primary procedures (6.52 %) had less complications than the operations for a recurrence of Crohn's disease (17.70 %). The rate for the recurrence of Crohn's disease was 17.4 % after 5 years, 36.7 % after 10 years and 52.8 % after 15 years. Patients with fistulas as the indication for primary operation had the highest rate of recurrence (45 %). Patients with an isolated Crohn's lesion of the small intestine had a significantly higher risk for recurrence (59.5 %) than patients with lesions in the ileocoecal region or the colon. The anastomosis region (73 %) was the most common localisation for recurrence."] Does [ Recurrence of Crohn 's disease after surgery -- cause and risks ]?