CT predictors of failed laparoscopic appendectomy

PURPOSE: To identify computed tomographic (CT) signs that may help predict possible failure of laparoscopic appendectomy and subsequent conversion to open appendectomy. MATERIALS AND METHODS: Of 234 consecutive patients who underwent preoperative CT and in whom laparoscopic appendectomy was attempted, 26 required conversion to open appendectomy. Conversion was correlated with the following CT findings: appendix location, appendicolith, cecal wall thickening involving the base of the appendix, lymphadenopathy, and appendiceal diameter. The extent of inflammation was graded by using a six-point scale: 0 meant normal appendix; 1, possibly abnormal appendix (6-mm diameter without other abnormality); 2, abnormal appendix (diameter greater than or equal to 6 mm with wall enhancement) without adjacent fat stranding; 3, abnormal appendix surrounded by fat stranding; 4, abnormal appendix surrounded by fat stranding and fluid; and 5; inflammatory mass or abscess. Student t and chi(2) tests were used for statistical analysis of interval and nominal values, respectively. RESULTS: Although there was a significant difference in appendiceal diameter between the patients in whom laparoscopic appendectomy was successfully completed (11.3 mm +/- 3.5 [SD]) and those who required conversion (12.9 mm +/- 3.9), no distinct cutoff point was identified: Of the five CT findings evaluated, none was a significant predictor of conversion to open appendectomy. Eleven (7%) of 164 patients with a CT inflammation grade of 0-3 required conversion, whereas 15 (21 %) of 70 patients with a grade of 4 or 5 required conversion (P < .04). CONCLUSION: The majority of patients with appendicitis can be treated with laparoscopic appendectomy. Nevertheless; patients who require conversion to open appendectomy tend to have high CT inflammation grades of 4 or 5, which indicate the presence of periappendiceal fluid or an inflammatory mass or abscess. (C) RSNA, 2003.