Objective: Keyhole deformity is frequently encountered after posterior internal sphincterotomy but may be observed after lateral internal sphincterotomy or in patients without any history of previous anal surgery. The aim of the present study is to emphasize the surgical significance of this entity and discuss the possible strategies in the treatment of the deformity.
Material and methods: Patients in whom keyhole deformity developed after surgical or conservative treatment applied for chronic anal fissure in our clinic and patients referred from other centers were recruited.
Results: Nine-hundred twenty-six patients were treated for chronic anal fissure. A hundred of these patients directly underwent lateral internal sphincterotomy. The remaining 826 patients initially received conservative management, and 676 of them eventually underwent lateral internal sphincterotomy. In total, 15 patients were diagnosed to have significant keyhole deformity. Initially, all patients received conservative treatment for keyhole deformity, which was successful in two patients. Of the 13 patients in whom conservative management failed, nine underwent advancement flap reconstruction and the remaining four diamond flap reconstruction.
Conclusion: Keyhole deformity is occasionally seen as a late complication of chronic anal fissure and may be well tolerated by the patients without any well-defined symptoms. The treatment strategy is directed toward the degree of functional alteration.