F2 and obesity disorder: ASA 4 patients showed an increased risk of developing chronic cutaneous fistula compared to ASA 3 patients (OR 4.8, 95 CI 1.1 to 21.1, p = 0.03), while the type of resection, age, sex, obesity, the intake of antiplatelet and anticoagulant agents, partial thromboplastin time, prothrombin time and relevant postoperative bleeding did not influence the infection recurrence.