About Pilonidal Sinus
Pilonidal sinus is a relatively common condition effecting mainly young males but certainly females can be effected also. The typical site is over the coccyx or tailbone. Hairs from the back or buttock get pushed through the skin usually in the midline just above the buttock crease and then pushed further in by pressure. Because hairs have scales it is one way traffic – they cannot back out. The other significant issue of course is that hairs carry bacteria in with them and this sets up an infection. Once under the skin the hairs are then pushed through the subcutaneous tissues and they can travel in any direction and for quite some distance. Whilst most pilonidal sinuses have a solitary hole in the skin there can be multiple holes resulting in a veritable rabbit warren of subcutaneous tracks and chronic abscesses opening and discharging onto the surface.
Most patients give a chronic history of the condition but it can present acutely in the form of an abscess.
A pilonidal sinus is treated by firstly settling any acute infection with antibiotics. If there is an abscess this needs to be drained without delay (see separate document). Once the infection has settled then definitive management is carried out and this is in the form of an excision. It is important to excise all sinuses and sub cutaneous tracts and this is done as an ellipse down to the sacrococcygeal periosteum (the fibrous lining of these bones). Almost always the defect is small enough to allow a direct closure and this is achieved by moving some skin from one buttock cheek over to the other. It is important to leave the incision off the midline because if It is left on the midline then the recurrence rate tends to be higher.
If the area of excision is extensive and this is usually predictable then under these circumstances the wound is allowed to heal by secondary intention which is from the base up and this requires a daily change of dressing for approximately six weeks.
If primary closure has been achieved then the vast majority of wounds heal and remain closed. A small percentage (probably 5-10%) will dehisce (breakdown) when the sutures are removed on day 10-12. This usually happens because of infection which gets in at the time of the original surgery. It is almost impossible to eradicate the bacteria during the initial procedure as the subcutaneous hairs are present throughout. If the wound does dehisce then it is managed in the same way that the wound would have been managed if primary closure had not been achieved in the first place.
It is essential to keep the area hair free after the surgery and this will certainly decrease dramatically the chances of the patient suffering a recurrence. Initially this should be done using a razor but in the long term can be achieved very effectively with laser. This is also a permanent solution.