NMS. Casos Clínicos

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Part II ♦ Specific Disorders

Figure 8-45: Closed internal lateral sphincterotomy: insertion of the cataract scalpel into the intersphincteric groove. The blade of the cataract scalpel is inserted into the groove, parallel to the plane of the sphincters, in order to avoid inadvertent injury to the external sphincter upon insertion. (From Albo D. Operative Techniques in Colon and Rectal Surgery . Wolters Kluwer Health; 2015, Fig. 46-6.) Case 8.38 Persistent Perianal Drainage A patient presents with a history of persistent perianal drainage . On examination, a sinus tract with granulation tissue is apparent.

Deep and superficial external sphincter Q: What is the most likely diagnosis? A: This patient most likely has a fistula-in-ano , which is the residua of a previous abscess that failed to completely heal (Fig. 8-46). Instead, a chronic tract formed, with an internal connection to an anal crypt, and an external connection to the perianal skin. SAMPLE Subcutaneous external sphincter Internal sphincter

D C

B A A Intersphincteric (75%) B Trans-sphincteric (20%)

C Suprasphincteric (5%) D Extrasphincteric (<1%)

Figure 8-46: Typical fistula-in-ano. (From McKenney MG, Mangonon PC, Moylan JA, eds. Understanding Surgical Disease: The Miami Manual of Surgery . Philadelphia: Lippincott- Raven; 1998:162.)