Safeguarding Surgeons: Utility of Ultrasonography and Computed Tomography in Reducing Diagnostic Errors in Acute Appendicitis
Maj Rahul Pandey, P-145/802, Sekhon Vihar, Palam, New Delhi, India.
Introduction: Correct and urgent decision making in Acute Appendicitis (AA) is very challenging. Operative treatment based only on clinical examination has a high Negative Appendectomy Rate (NAR). Diagnostic accuracy of clinical algorithm is poor thus many surgeons resort to imaging modalities. There are medico-legal risks to surgeons either due to delayed treatment or due to diagnostic error in cases of AA leading to cases of litigation against them. Thus, complimenting a clinical diagnosis with imaging becomes a safe option in the current surgical practice.
Aim: To assess the utility of abdominal Ultrasonography (USG) and Computed Tomography (CT) Scan in reducing diagnostic errors in AA.
Materials and Methods: A prospective observational study was done in a tertiary care teaching hospital. The diagnostic efficacy of Alvarado Scores (AS), USG and CT scan were studied in terms of measurable outcomes such as sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), diagnostic accuracy and NAR.
Results: Seventy five males and 27 females with a mean age of 27.5±10.0 years were studied. All patients underwent appendiceal USG, while 33 patients underwent CT scan. NAR was 9.33% in males and 14.8% in females with overall NAR of 10.78%. The overall sensitivity, specificity, PPV, NPV and diagnostic accuracy of AS was 78.02%, 72.73%, 95.95%, 28.57% and 77.45% respectively which was higher in males. The overall sensitivity, specificity, PPV, NPV and diagnostic accuracy of USG was 94.51%, 81.82%, 97.73%, 64.29% and 93.14% respectively and had a higher value in males. CT scan had an overall sensitivity of 96.00% and specificity of 100%. In patients with AS <7, USG and CT scan had better sensitivity, specificity, PPV, NPV and higher diagnostic accuracy.
Conclusion: AS is a useful tool for diagnosing AA when AS is =7. USG is more sensitive, specific and has a higher diagnostic accuracy than AS. In patients with AS <7, USG has better sensitivity, specificity, NPV and diagnostic accuracy. CT scan has highest sensitivity, specificity and diagnostic accuracy compared to AS and USG. CT scan is more beneficial when AS is <7. On combining AS, USG and CT scan overall sensitivity, NPV and diagnostic accuracy of tests improved. USG should be used as an adjunct in all patients of suspected AA. CT scan use is highlighted in equivocal cases in which AS and USG cannot establish thereby reducing diagnostic errors in AA.