Goodsall’s rule– its predictive accuracy in tracing the tract of fistula in ano

Abstract

Background: Despite being one of the oldest reported medical conditions, the management and treatment of fistula in ano are still in the evolving phase. The management of fistula-in-ano requires confirmation of the diagnosis, identifying the fistulous tract and inner opening. In majority of patients a single primary fistula tract exists and the anatomy can be determined by examination under anaesthesia adhering to the principles described by Goodsall. A thorough clinical examination of the patient is essential in the assessment of fistula-in-ano, sometimes helped by imaging such as magnetic resonance imaging and endoanal ultrasonography. Although Goodsall’s rule was accepted in the past, as a method to determine the course of the fistula, recent studies showed poor conflicting results. Thus, this study attempts to scrutinize the predictive accuracy of Goodsall’s rule. Methods: After approval from ethical committee and obtaining informed consent from each patient, prospective analysis of 188 patients who has fistula-in-ano were included in the study. They were grouped according to Goodsall’s rule and its predictive accuracy was checked with intraoperative findings. Data was entered in excel sheet and analysed by SPSS version 20.0. For all statistical interpretations, p<0.05 was considered the threshold for statistical significance.Results: Predictive accuracy of Goodsall’s rule found to be 84.6% in case of fistula with an anterior external opening. While in case of fistula with posterior external opening this found to be 69.1%. Overall predictive accuracy of Goodsall’s rule is 77%. Conclusions: Goodsall’s rule can be used as guide in predicting the tract.