Introduction of appendiceal CT - Impact on negative appendectomy and appendiceal perforation rates

Objective To evaluate the impact of appendiceal computed tomography (CT) availability on negative appendectomy and appendiceal perforation rates. Summary Background Data Appendiceal CT is 98% accurate. However, its impact on negative appendectom y and appendiceal perforation rates has not been reported. Methods The authors reviewed the medical records of 493 consecutive patients who un derwent appendectomy between 1992 and 1995, 209 consecutive patients who un derwent appendectomy in 1997 (59% of whom had appendiceal CT), and 206 pati ents who underwent appendiceal CT in 1997 without subsequent appendectomy. Results Before appendiceal CT, 98/493 patients (20%) taken to surgery had a normal appendix. After CT availability, 15/209 patients (7%) taken to surgery had a normal appendix; 7 patients did not have CT, 5 patients had surgery despi te a negative CT, and 3 patients had a false-positive CT. Negative appendec tomy rates were lowered overall (20% to 7%), in men (11% to 5%), in women ( 35% to 11%), in boys (10% to 5%), and in girls (18% to 12%), Appendiceal pe rforation rates dropped from 22% to 14% after CT availability. CT excluded appendicitis in 206 patients in 1997 who avoided appendectomy and identifie d alternative diagnoses in 105 of these patients (51%). Conclusion The availability oi appendiceal CT coincided with a drop in the negative ap pendectomy rate from 20% to 7% in all patients, and to only 3% in patients with a positive CT. Perforation rates decreased from 22% to 14%, Appendicea l CT can be advocated in nearly ail female and many male patients.