Background: Diagnostic laparoscopy is the ultimate diagnostic tool to evaluate the appendix. Still, according to the literature, this strategy results in a negative appendectomy rate of approximately 12-18 % and associated morbidity. Laparoscopic criteria for determining appendicitis are lacking. The goal of this study is to define clear and reliable criteria for appendicitis during diagnostic laparoscopy that eventually may safely reduce the negative appendectomy rate.
Methods: From December 2009 through April 2011, 134 patients were included and analysed in a single-centre prospective pilot study. Intraoperatively, the appendix was evaluated by the surgeon according to nine criteria for appendicitis. The operating surgeon decided whether it should be removed or not. Immediately after the operation the surgeon had to complete a questionnaire on nine criteria for appendicitis. All removed appendices were examined by a pathologist. In case the appendix was not removed, the clinical postoperative course was decisive for the (missed) presence of appendicitis.
Results: In 109 cases an inflamed appendix was removed; in 25 patients the appendix was normal, 3 of which had been removed. After univariate analysis and clinical judgement six variables were included in the Laparoscopic APPendicitis score (LAPP score). In this study, use of the LAPP score would have led to a positive predictive value of 99 % and a negative predictive value of 100 %.
Conclusions: This study presents the LAPP score. The LAPP score is an easily applicable score that can be used by surgeons to evaluate the appendix during diagnostic laparoscopy. The score has high positive and negative predictive value. The LAPP score needs to be validated in a multicentre validation study.