Abstract

LOPEZ MONCLOVA, Julio César; MARTINEZ CONTRERAS, Arturo; ZAMARRON RUVALCABA, Anabel  and  RODRIGUEZ GOMEZ, Karime. Negative appendectomies and their relation with imaging studies. Cir. gen [online]. 2011, vol.33, n.4, pp.222-226. ISSN 1405-0099.

Objective: To identify whether diagnostic imaging, such as computed axial tomography (CAT) and ultrasonography (US) can be associated with a lower incidence of negative appendectomies. Setting: Hospital Christus Muguerza del Parque, private third level health care hospital. Design: Diagnostic test, retrospective, descriptive, observational, cross-sectional study. Statistical analysis: Sensitivity, specificity, predictive values, and Bayesian testing. Patients and methods: All patients subjected to appendectomy in the period from January 2006 to December 2008 were included in the study. The histopathological report, as diagnostic gold standard, was correlated with the imaging studies, CAT und US, in patients with clinical symptoms suggestive of acute appendicitis. Results: We included 207 patients, 107 were men (52%) and 100 women (48%). In 183 patients (88.4%) subjected to appendectomy, the histopathological diagnosis of acute appendicitis was confirmed, whereas the remainder 24 patients (11.6%) had negative appendectomies, these corresponded to 10 men and 14 women. During the study period, the frequency of negative appendectomies decreased 66% in 2008 with respect to 2007, concurrently the use of CAT to assess these cases increased 41%. CAT presented a sensitivity of 89%, specificity of 60%, positive predictive value (PPV) of 94.8% and negative predictive value (NPV) of 40%, the possibility of negative post-test (PNPT) was of 59.9%. US had a sensitivity of 63%, specificity of 40%, PPV of 85.5% and NPV of 15.8%, and PNPT of 84.2%. Conclusions: Neither the increase in the use of CAT with IV contrast medium nor of US was associated with a lower incidence of negative appendectomies. The clinical criterion remains being valid

Keywords : Acute appendicitis; appendicular abscess; negative appendectomy; computed tomography scan; ultrasonography.