In the ILA group, the median interval from discharge of the initial non-surgical treatment to the surgery was 110 days. Demographic and clinical characteristics of patients in the ILA group and the LA group are shown in Table 1. The ILA group was older, used more anticoagulant or antiplatelet agents, and had higher ASA score and Charlson Comorbidity Index than the LA group [age (years): 56.5 vs 37, P < 0.01; anticoagulant or antiplatelet usage (cases): 5 vs 10, P < 0.01; ASA-classification (1/2/3): 14/12/8 vs 279/185/13, P < 0.01; Charlson Comorbidity Index (0 / 1 / 2 / 3 / 4 / 5 / 6): 22 / 4 / 5 / 2 / 0 / 1 / 0 vs 414 / 40 / 15 / 5 / 1 / 0 / 2, P < 0.01]. Considering surgical procedures, in the ILA group, Endloop was statistically used and a 10-mm trocar was tended to be used [appendix stump closure (Endostapler/Endoloop): 13/21 vs 298/179; P < 0.01, use of 10-mm trocar (use/not use): 28/6 vs 440/37, P = 0.055]. Though the operation time in the ILA group was longer than that of the LA group, the postoperative hospital stay was shorter, and there was no difference between the bleeding volume and the nunber of days required until oral intake of solid food after surgery between the two groups [operation time (mins): 64 vs 56, P < 0.01; postoperative hospital stay (days): 2 vs 3, P < 0.01] [Table 2]. Regarding perioperative complications, there was 1 case of small bowel obstruction in the ILA group. In the LA group, there were 12 cases of wound infection, 1 case of anorexia, 1 case of damage to other internal organ at the time of the first trocar insertion, 1 case of transient liver injury. There were no significant differences in the perioperative complications between the two groups.
The median number of days from start of non-surgical treatment to perform the surgery in the non-ILA because of failure of non-surgical treatment or relapse of inflammation was 9 days. The characteristics of the ILA group and the non-ILA group are shown in Table 3, among which WBC day3 / day0 and CRP day3 / day0 showed a statistical difference between the two groups [WBC day3 / day0: 0.67 vs 0.97, P < 0.01; CRP day3 / day0: 0.58 vs 1.21, P = 0.011]. The univariate analysis indicated mass size and WBC day3 / day0 were considered as factors that could influence the failure of non-surgical treatment or relapse of inflammation during interval period [mass size: P = 0.017; WBC day3 / day0: P = 0.013] [Table 4]. Furthermore, multivariate analysis considering the results of the univariate analysis indicated that WBC day3 / day0 is an independent factor that could influence ita [P = 0.045] [Table 4]. In addition, WBC day3 / day0 showed the highest sensitivity and specificity at a cut off value of 0.906 [sensitivity 0.750, specificity 0.794] [Fig. 2]. Using the cut off value, the patients were divided into two groups as the high and low WBC day3 / day0, resulting in a statistically higher proportion of the high WBC day3 / day0 in the non-ILA group than the ILA group [P < 0.01] [Table 5].
In comparison between the ILA group and the non-ILA group, significant differences were found in operation time, bleeding volume, postoperative hospital stay, and days required until oral intake of solid food after surgery [operation time (mins): 64 vs 161, P < 0.01; bleeding volume (ml): 2 vs 200, P < 0.01; postoperative hospital stay (days): 2 vs 9, P < 0.01; days required until oral intake of solid food (days): 1 vs 3, P < 0.01]. Regarding perioperative complications, there were significant differences between the two groups in conversion to laparotomy, postoperative drainage tube placement, small bowel obstruction
, and postoperative residual abscess [conversion to laparotomy: 0 vs 3, P = 0.025; postoperative drainage tube placement: 0 vs 3, P = 0.025; small bowel obstruction: 1 vs 4, P = 0.026; residual abscess: 0 vs 4, P < 0.01) [Table 6].
Preoperative colonoscopy was performed for 27 of 34 cases in the ILA group, but no neoplastic lesion was found. Postoperative pathological examination revealed 1 case of appendiceal malignant disease in each of the ILA group and the non-ILA group.