Current Therapy of Cryptoglandular Anal Fistula: Gold Standards and Alternative Methods

Cryptoglandular anal fistulas are one of the most common colorectal diseases and occur with an incidence of about 20/100,000. Anal fistulas are defined as an inflammatory junction between the anal canal and the perianal skin. They develop from an abscess or chronic infection of the anorectum. Surgical treatment of the disease is the method of choice. Even when treating an acute abscess, its cause should be sought at the same time. If there is a connection to the anal canal without affecting relevant parts of the sphincter muscles, primary fistulotomy should be performed. If larger parts of the sphincter muscle are involved, the insertion of a seton drain is usually useful. There are essentially two recommendations for the elective treatment of cryptoglandular anal fistulas. Distal fistulas should be excised, with the proviso that as little sphincter muscle as possible is sacrificed. In the case of highly proximally located and complex fistulas, sphincter-preserving surgical techniques should be used. In this case, the method of choice is the mucosal or advancement flap. Alternatively, clips, fibrin injections, fistula plugs, fistula ligatures, or laser-based procedures are described in the literature. In the case of intermediate fistulas, a fistulectomy with primary sphincter reconstruction can be useful. Every operation is carried out as a compromise between definitive healing of the fistula and a potential risk to the patient's continence. It is often difficult to make a reliable prognosis about the continence function to be expected postoperatively. In addition to the fistula morphology, particular attention should be paid to whether previous proctological operations have already been performed, the gender of the patient, and whether there are pre-existing sphincter dysfunctions. Since the surgeon's expertise plays a decisive role in the success of the treatment, the procedure should be carried out in a specialist proctological centre, especially in the case of complex fistulas or in the case of a condition after previous operations. In addition to the classic procedures, such as fistulectomy or the plastic fistula closure, this article examines alternative methods and their areas of application.