Healing by primary versus secondary intention after surgical treatment for pilonidal sinus

Pilonidal sinus arises in the hair follicles in the buttock cleft. The estimated incidence is 26 per 100,000, people, affecting men twice as often as women. These chronic discharging wounds cause pain and impact upon quality of life. Surgical strategies centre on excision of the sinus tracts followed by primary closure and healing by primary intention or leaving the wound open to heal by secondary intention. There is uncertainty as to whether open or closed surgical management is more effective.

To determine the relative effects of open compared with closed surgical treatment for pilonidal sinus on the outcomes of time to healing, infection and recurrence rate.

For this first update we searched the Wounds Group Specialised Register (24/9/09); The Cochrane Central Register of Controlled Trials (CENTRAL) - The Cochrane Library Issue 3 2009; Ovid MEDLINE (1950 - September Week 3, 2009); Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations (September 24, 2009); Ovid EMBASE (1980 - 2009 Week 38); EBSCO CINAHL (1982 - September Week 3, 2009).

All randomised controlled trials (RCTs) comparing open with closed surgical treatment for pilonidal sinus. Exclusion criteria were: non-RCTs; children aged younger than 14 years and studies of pilonidal abscess.

Data extraction and risk of bias assessment were conducted independently by three review authors (AA/IM/JB). Mean differences were used for continuous outcomes and relative risks with 95% confidence intervals for dichotomous outcomes.

For this update, 8 additional trials were identified giving a total of 26 included studies (n=2530). 17 studies compared open wound healing with surgical closure. Healing times were faster after surgical closure compared with open healing. Surgical site infection (SSI) rates did not differ between treatments; recurrence rates were lower in open healing than with primary closure (RR 0.60, 95% CI 0.42 to 0.87). Six studies compared surgical midline with off-midline closure. Healing times were faster after off-midline closure (MD 5.4 days, 95% CI 2.3 to 8.5). SSI rates were higher after midline closure (RR 3.72, 95% CI 1.86 to 7.42) and recurrence rates were higher after midline closure (Peto OR 4.54, 95% CI 2.30 to 8.96).

No clear benefit was shown for open healing over surgical closure. A clear benefit was shown in favour of off-midline rather than midline wound closure. When closure of pilonidal sinuses is the desired surgical option, off-midline closure should be the standard management.