Tomoyuki Abe,1 Takashi Nagaie,1 Mitsuhiro Miyazaki,1 Miho Ochi,2 Tatsuro Fukuya,2 Kiyoshi Kajiyama11Department of Surgery, Aso Iizuka Hospital, Iizuka City, Fukuoka, Japan; 2Department of Radiology, Aso Iizuka Hospital, Iizuka City, Fukuoka, JapanPurpose: Laparoscopic appendectomy (LA) for acute appendicitis has several advantages over open appendectomy (OA). In cases of complicated appendicitis, LA is converted to OA at a constant rate, though converting appendectomy (CA) has several disadvantages. We retrospectively determined preoperative risk factors for failure of LA and subsequent conversion to OA.Methods: Consecutive cases of preoperative computed tomography (CT) and attempted LA were retrieved from our hospital database and grouped by procedure (LA versus CA). Patients with negative appendectomies (n = 28), opened appendectomy (n = 210), delayed interval appendectomy (n = 3), or who were