Negative Appendectomy and its Related Factors in 1211 Cases Undergoing Appendectomy

Acute appendicitis is still the most common acute surgical disease. The aim of this study was to evaluate the frequency of symptoms, signs, paraclinical findings and diagnostic value of these findings in prediction of acute appendicitis in patients suspicious of having this problem. In this study 1121 patients, suspicious of acute appendicitis, were operated and surveyed in the period of two years. One way ANOVA, kappa and odds ratio correlation coefficient and logistic regression model were used to analyse the data and to predict the occurrence of acute appendicitis. 92.4% of the patients were males, and the average age was 24.1 years. The rate of negative appendectomy in this study was 18.2%, which ranged between 4% and 27.7% based on diagnosis made by various physicians(P=0.001). The regression model revealed that among factors which showed significant difference between negative appendectomy patients and the rest, only older age(P=0.005), male gender(P=0.002), higher percenage of PMN(P=0.027) and higher heart rate(P=0.014) could be regarded as independent predictors of acute appendicitis(P<0.001). In conclusion, based on the results of this study, it is reasonable to be hesitant about operating a female patient suspicious of having acute appendicitis, if she has a PMN percentage of lower than 75%, white cells less than 10,000 in milliliter, urinary symptoms and no rebound tenderness or questionable rebound tenderness.