Classification of Anal Fistula and Abscess

Abstract

Classification is required for any disease so that the disease can be graded both for its severity or complexity. Moreover, a treatment guideline could be provided according to the grades of the classification. The process of classifying anal fistulas started in 1934, and since then, it has evolved a lot. The initial classifications categorized anal fistulas broadly as fistulas above the anorectal sling or the fistulas below the anorectal sling. However, in 1950s, the role of intersphincteric space in the pathogenesis and spread of fistulas was discovered. Since then, a major change came in the direction of classifying fistulas. All the subsequent classifications categorized fistulas primarily as either intersphincteric or transsphincteric. These included commonly used Parks and St James’s University Hospital classifications. However, the main drawback of these classifications was that they did not guide the management of the disease. In the last decade, a new classification known as Garg classification tried to remove this major drawback. This classification divided fistulas primarily as low (involving less than one-thirds of the external sphincter) and high (involving more than one-thirds of the external sphincter). Apart from being the most comprehensive classification to be proposed, Garg classification seems to have optimally addressed both the issues, classifying fistulas on the basis of their complexity and acting as a guide regarding the management of the disease. Among all classifications, the three most relevant classifications, Parks, St James’s University Hospital, and Garg classifications, would be discussed in detail.