A fistula in ano is a track that develops from the inner lining of the anus through the tissues that surround the anal canal. (The anal canal is the last 3-4 cm of the intestine, and ends at the anus.) The track opens into the skin near the anus. The track gets repeatedly infected by bacteria in the stool, becomes painful, and discharges pus.
A high fistula takes a long path and goes through an important muscle, the levator ani. The following link will show images of anal fistulas: http://www.netterimages.com/images/vpv/000/000/004/4310-0550x0350.jpg,
http://www.cem.org.hk/gallery/albums/album18/fistula_in_ano.thumb.jpg
Fistulas are treated by surgically removing the entire false track, and the surrounding tissues. However, an alternative therapy is the Ayurvedic thread therapy, first used 2500 years ago by Sushruta. It is very effective but not feasible in all fistulas, as the track is sometimes too tortuous to be threaded.
Surgery for high fistula is not dangerous, but quite difficult. Recurrence rates may reach 10-20%.
Loss of ability to control stool is the worrying postoperative complication. This complication of incontinence does not occur after surgery for low fistula. Incontinence is also unlikely after thread therapy, even if the fistula is high.
Bed rest = 1-3 days; away from job = 2-4 weeks. Pain after surgery: may be significant for 1-2 days, but subsequently there is very little pain.