Healing by primary closure versus open healing after surgery for pilonidal sinus: systematic review and meta-analysis

Objective To compare open heating with primary closure for pilonidal sinus and optimal closure method (midline v off-midline).
Design Systematic review and meta-analyses of randomised controlled trials.
Data sources Cochrane register of controlled trials, Cochrane Wounds Group specialised trials register, Medline (1950-2007), Embase, and CINAHL bibliographic databases, without language restrictions.
Data extraction Primary outcomes were time to healing, surgical site infection, and recurrence rate. Secondary outcomes were time to return to work, other complications, cost, length of hospital stay, and wound heating rate.
Study selection Randomised controlled trials evaluating surgical treatment of pilonidal sinus in patients aged 14 years or more. Data were extracted independently by two reviewers and assessed for quality. Meta-analyses used fixed and random effects models, dichotomous data were reported as relative risks or Peto odds ratios and continuous data are given as mean differences; all with 95% confidence intervals.
Results 18 trials (n=1573) were included. 12 trials compared open heating with primary closure. Time to healing was quicker after primary closure although data were unsuitable for aggregation. Rates of surgical site infection did not differ; recurrence was less likely to occur after open heating (relative risk 0.42, 0.26 to 0.66). 14 patients would require their wound to heal by open heating to prevent one recurrence. Six trials compared surgical closure methods (midline v off-midline). Wounds took longer to heat after midline closure (mean difference 5. 4 days, 95% confidence interval 2.3 to 8.5), rate of infection was higher (relative risk 4.70, 95% confidence interval 1.93 to 11.45), and risk of recurrence was increased (Peto odds ratio 4.95, 95% confidence interval 2.18 to 11.24). Nine patients would need to be treated to prevent one surgical site infection and 11 would need to be treated to prevent one recurrence after off-midline closure.
Conclusions Wounds heal more quickly after primary closure but at the expense of increased risk of recurrence. Benefits were clearly shown with off-midline closure than with midline closure. Off-midline closure should become standard management for pilonidal sinus when closure is the desired surgical option.