According to recent findings, pilonidal sinus is an acquired disease, while the congenital origin discussed in the past seems unlikely today.
The following factors are assumed to be predisposing in the development: Male sex, obesity, excessive hair in the anal cleft, poor personal hygiene, sitting occupations, deep gluteal fold, positive family history.
Hair plays a special role in this context: As early as the 1980s, F. Stelzner proved that hair, fixed by small barbs, can penetrate the skin. A further indication that hair plays an important role is the fact that pilonidal sinus is unknown in China since Chinese have no hair in the anal cleft.
The latest 2014 update of the guideline of the German Society of Coloproctology of recommends open surgery as the treatment of choice.
The abscess is first unroofed widely to allow effective drainage. Definitive treatment of the pilonidal sinus is then performed in the second stage by following one of these two procedures:
- Excision with secondary wound healing or
- Excision with primary wound closure (only in infect-free stage!) → after excision, the wound is primarily closed by suture or plastic reconstruction.
Local or systemic antibiotics should not be administered because they do not result in definitive healing of the sinus. The injection of phenol solution is obsolete because of its high toxicity and possible absorption of the phenol.
There is no spontaneous healing. An asymptomatic pilonidal sinus persists for life but may also enter the acute (abscess) or the chronic stage. After longer persistence a malignant transformation is theoretically possible, but only in rare cases have been described in the literature.
After excision, healing by second intention does not tend to be significantly more effective than primary healing. The recurrence rate is lower in open surgery (significant in current Cochrane analysis).
As a matter of principle, the pilonidal sinus should be excised in toto. Typically, the excision of the granulation pannus must be carried down close to the sacral fascia. In the literature, however, there is no sure indication that this should involve the periosteum. In contrast, however, it must be presumed that excision of the periosteum denuding the sacrum will increase postoperative pain and significantly worsen healing.
In order to ensure full excision, it is recommended to mark the rabbit warren of inflamed tissue with toluidine blue. Doll et al. were able to demonstrate that the use of toluidine blue has a significant impact on the recurrence rate.
Primary mid-line wound closure after excision of pilonidal sinus correlates with a high postoperative morbidity and recurrence rate. In primary mid-line wound closure, the incidence of wound healing disorders is 30% or more.
In open wound treatment, it is not unusual for the healing to take more than 3 months.
Due to the prolonged postoperative treatment and the socio-economic burden, open wound treatment is not an optimal alternative (multiple recurrences are also not ideal). Surgical techniques avoiding a median wound and flattening the gluteal fold appear to be useful and could provide better short-term and long-term results. This requires further studies are required.
Systemic preoperative prophylactic antibiotics do not appear to affect wound healing. This was demonstrated by the prospective randomized trial of Sondenaa. Other reports also confirmed this observation.
In theory, depilation should reduce the recurrence rate. Nevertheless, it has been known for some time that mechanical hair removal by shaving with a razor does not offer any benefit. Stirnemann and Blasimann already reported in 1983 that the recurrence rate cannot be reduced by mechanical shaving. A 2009 cohort trial by the German Armed Forces also demonstrated the same effect, with mechanical shaving even promoting the development of recurrences (Petersen 2009). Whether hair removal without producing additional broken hair (laser depilation) could become a promising treatment option in preventing recurrence is the subject of further research and cannot be recommended generally at present.