Apilonidal sinus (PS) or sacrococcygeal fistula, is a cyst, abscess or sinus tract located at the natal cleft of the buttocks.

A pilonidal sinus or sacrococcygeal fistula, is a cyst, abscess or sinus tract located at the natal cleft of the buttocks, that often contains hair and/or an epithelialised sinus tract that delays wound healing. This paper discusses 20 patients with pilonidal sinuses who were analysed over a three-year period. Ten cases had a new treatment regimen applied while 10 cases were treated with traditional therapy. The former group resulted in full healing in nine out 10 cases, as opposed to three of 10 in the traditionally treated group. Although the sample size is too small to make definitive recommendations, certain observations can be drawn.