ABSTRACT
<p><b>OBJECTIVE</b>To investigate the clinical features of Crohn disease according to the Montreal classification.</p><p><b>METHODS</b>Clinical data of 43 surgical patients with Crohn disease (surgical group) and 125 non-surgical patients with Crohn disease (non-surgical group) were retrospectively analyzed and compared between two groups. The Montreal classification was used.</p><p><b>RESULTS</b>In the surgical group, 28 patients (65.1%) were A2, 14 (32.6%) were A3 and only one was A1, which was not significantly different as compared to the non-surgery group. The proportions of L1, L2, L3, and L4 subtype in the surgical group were 41.9%, 25.6%, 30.2%, and 2.3%, respectively, which was not significantly different as compared to that in the non-surgery group. In the surgical group,B1 disease was found in 1 case (2.3%), B2 in 26 cases (60.5%), and B3 in 16 cases (37.2%), while in the non-surgical group, B1 was found in 79 cases (63.2%), B2 in 44 cases (35.2%) and B3 in 2 cases (1.6%). Differences were significant between two groups in disease behavior (P=0.001, P=0.004, P=0.001).</p><p><b>CONCLUSIONS</b>Most surgical patients of Crohn disease are A2. L1 and L3 are the main lesion location. As disease behavior, B2 and B3 are the main reasons for operation.</p>