The sensitivity of plain films for detecting perforation in children with appendicitis

The plain films of 37 patients under age 18 with surgically and pathologically proven non perforated (16/37) and ruptured (21/37) appendicitis were reviewed in order to determine the ability of the plain film to specify perforation. Perforation was suggested when one or more of the following six findings were clearly defined: 1. Acute small bowel obstruction. 2. Extraluminal gas. 3. Mass in the right lower quadrant. 4. Colon cut-off sign at the hepatic flexure. 5. Fecalith. 6. Obliteration of the pelvic fat planes. This approach resulted in a sensitivity of 80% and a specificity of 94%, with the only false positive for perforation occurring in a patient with a fecalith. In five patients, extraluminal gas produced a triangular accumulation in the right flank which could be distinguished from intraluminal bowel gas on the supine or prone film.