Pilonidal sinus is disease that is based on primary openings, which exist in the midline of the cleft between the buttocks (these openings are the ends of fistulas, which begin from coccyx apex).
This is congenital malformation, embryonic caudal remnants.
Pilonidal sinus usually is a slim canal in subcutaneous fat, which is lined by epithelium and begin from coccyx apex. External openings always are in the midline of the cleft between the buttocks. In 40% of cases hairs exist in these canals (and they come out from external openings). That can be one or several openings.
In some cases (cold, trauma, deficient hygiene ecc) this canal is not drainaged enough and fills out by epithelium, glandule’s excretion ecc., and as a result, pilonidal sinus suppurates. This is acute period.
Diagnosis is based on examination of sacral and coccygeal region (midline sinus opening or inflammation signs in this area). Digital examination is necessary to exclude anal fistula.
Pilonidal sinus can be hilled only by operation (which involves excision of fistula and surrounding fat).