The Garg classification for anal fistulas is accurate and robust,due to which it has stood the test of time: Update from the innovator

We read with great interest the excellent article, in which the accuracy of the Garg classification for anal fistulae was demonstrated and its superiority over Parks, St James University Hospital (SJUH) and Standard Practice Task Force (SPTF) classifications in surgical decision making was highlighted. ¹

We innovated and published the Garg classification in 2017. ² This was needed because the existing classifications neither graded fistulae according to their severity nor guided surgeons regarding their disease management in any manner. Because of this, the purpose of classifying this disease was clearly deficient. The Garg classification not only classified fistulae according to their severity but also gave guidance for their management.

In guiding management, Garg classification was the first; it was also the first classification to be based on large patient data (440 patients). ² Moreover, it is the only classification that was validated in a cohort of 848 patients operated on for anal fistula. ³ The Garg classification is now utilised worldwide.^4–8

Recently, a structured magnetic resonance imaging (MRI) and endoanal ultrasound (EAUS) anal fistulas reporting template (SMART) was made by a large interdisciplinary Delphi consensus involving 95 experts (69 colorectal surgeons, 23 radiologists, 2 anatomists, and 1 gastroenterologist) from 31 countries and was endorsed by 11 scientific societies (3 radiological and 8 surgical). ⁸ The SMART template included and recommended the Garg classification as the main classification that should be used by radiologists and surgeons all over the world when reporting anal fistulae on MRI and EAUS. ⁸

A further update was the inclusion of a newly discovered fistula, RIFIL (fistulas at the roof of the ischiorectal fossa inferior to the levator muscle), in the Garg classification; after analysing thousands of MRI scans and their correlation with operative findings, a new observation was made: that several fistulae with origin in the inter-sphincteric space spreading and penetrating through the external anal sphincter (EAS) to become trans-sphincteric are contained by the ‘fascia covering the EAS’ and do not enter the ischiorectal fossa. This potential space between the EAS and the ‘fascia covering the EAS’ is termed the ‘outer sphincteric space’. Fistulae here may spread superiorly and inferiorly. ⁹ Inferiorly, they can reach the perianal skin, and superiorly, they can ascend in the outer sphincteric space along the inferior surface of the levator muscle. ¹⁰ When these ascending fistulas reach the level of the levator muscle, they are termed RIFIL fistulae. ¹⁰

There are significant management implications of these RIFIL fistulae. They not only enhance fistula complexity but also cause multiple recurrences and can lead to levator muscle injury, as they are often confused with high trans-sphincteric or supralevator fistulae. ¹⁰ Therefore, the RIFIL fistulae have been added as grade-V fistulae in the Garg classification. ⁸

To conclude, the Garg classification is not only accurate and comprehensive but also guides in the management of anal fistulas.