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 > or = 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 chi2 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.