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

Pilonidal sinus is a very common disease of the buttock region which mostly affects young adults (men more than women) and for many with the disease, the condition can be painful and long-lasting (chronic). The disease is thought to arise from ingrowing hair between the buttocks, which then becomes infected and forms into a "sinus" or tract. Patients with a pilonidal sinus usually present to their doctor with painful swelling around the buttock area, which may discharge pus-like substance. This disease is usually treated by surgery. Surgeons agree that the area where the infection has developed should be completely incised and removed. However, surgeons have not agreed whether the resulting wound should be stitched closed or left open to heal without stitches. This review of the published literature found that patients who had their wounds closed with stitches healed faster and returned to work earlier than patients whose wounds were left unstitched and allowed to heal "naturally". However, the review also found that patients who had their wounds closed with stitches were more likely to get the disease again compared to those who did not have their wounds closed by stitches. This means that each type of surgical treatment has its advantages and disadvantages, and that the decision about which type of surgical wound to select should also be guided by the patient's own desired goals for treatment. The review also found that if a decision had been made to close the wound with stitches, then the best way to reduce the risk of the disease coming back and reduce other complications (such as infection), was to use a wound technique where the line of stitches was moved away from between the buttocks. Therefore one definitive recommendation from this systematic review is that where a decision has been made to close the sinus wound using stitches, this wound should not lie in the central area of the buttocks.      

Authors' conclusions: 

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. 

Read the full abstract...

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.

Search strategy: 

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).

Selection criteria: 

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 collection and analysis: 

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.

Main results: 

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).