Aim: The aim of this study was to evaluate treatment of anal fistulae with deep post anal space affection 
using posterior midline approach compared to the conventional lay open method using the lateral approach.
Methods: Sixty patients with complex horseshoe fistulas of cryptoglandular origin, diagnosed by clinical 
examination and preoperative MRI were randomly allocated into 2 groups. Group A were subjected to the 
conventional lay open method while group B patients were subjected to the posterior midline approach. 
After the surgery the patients were followed up for a period of one year noting the healing time, effect on 
continence, and the occurrence of recurrence. 
Results: The mean healing time for group A was shorter than of group B. Patients of group B showed 
significant less time to regain their normal activity. Overall patients experienced little or no effect on the 
continence mechanism compared with their situation before surgery with slightly better results in the group 
B patients. The recurrence rate was 13.3% % for group A compared to 3.3% for group B with no statistical 
significance. 
Conclusion: The posterior midline approach is a good surgical approach for treating complex and horseshoe 
fistulas giving good results as regard healing time, effect on continence, and recurrence.