Appendectomy: developing a scoring system to improve diagnostic accuracy

ABSTRACT

Problems related to the diagnosis of appendicitis are evidenced by the significant negative laparotomy rate. The present study sought to assess the feasibility of decreasing this diagnostic error by studying two groups of patients and identifying and weighing details of history, physical examination and laboratory findings utilizing 20 predictive factors, 100 patients who underwent operation because of suspicion of acute appendicitis constituted the study sample, and were classified into AAp and NAp groups based upon the results of histologic examination. Rates of occurrence for each predictive factor were determined separately for both groups. These were converted into weights which were then added to yield a diagnostic score for each patient. A cutoff point established the score which designated one group for observation and the other for surgery. Scores were assessed at three different points by balancing risks of missed diagnoses against benefits of avoiding unnecessary operations. Seven predictive factors had differentiating weights and reached statistical significance [p marital status, duration of symptoms, initial site of pain, course of pain, temperature and WBC count. Using these seven predictors, at a [-3] cutoff, 61% NAps would have been spared laparotomy and about 6% of the AAps would have been indicated for observation. Analysis indicated little risk in observing the 6% AAps [2 cases]. This simple scoring system could have eliminated over one third of the unnecessary laparotomies in the present sample, indicating potential value as an aid in surgical decision-making. Our own findings, and those of many other authors, would seem to indicate that very close attention to the patient's history and clinical examination, coupled with pre-operative specialist consultation and exclusion of gynecological conditions would improve the ability of the clinical score system to determine cases of true appendicitis and hence the rate of negative appendectomies can be reduced, to a point without an appreciable rise in perforation rate