Primary acute torsion of the vermiform appendix.

A case of primary acute appendiceal torsion in a 6-year-old boy with symptoms suggestive of acute appendicitis is presented. The appendix was abnormally long, measuring 13.5 cm in length. Although appendicitis is the most common intra-abdominal surgical emergency, there are few descriptions of primary acute appendiceal torsion, a rare cause of an acute abdomen. A review of the English language literature disclosed 19 reports, including the present, with 11 pediatric cases. The site of torsion occurs most frequently 1 cm or more from the appendiceal base. Rotation varies from 270 degrees to 1080 degrees with a mean of 580 degrees. The direction of the rotation is more frequently anticlockwise. Appendix is most commonly described as lying free or pelvic. In children the mean age is 9.1 years, the range 3-16 years, and the male-to-female ratio 4.5:1.