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

OBJECTIVE: To determine the relative effects of open healing compared 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 (days) to healing, surgical site infection, and recurrence rate. Secondary outcomes were time to return to work, other complications and morbidity, cost, length of hospital stay, and wound healing 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 healing 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 healing (relative risk 0.42, 0.26 to 0.66). 14 patients would require their wound to heal by open healing to prevent one recurrence. Six trials compared surgical closure methods (midline v off-midline). Wounds took longer to heal after midline closure than after off-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 higher (Peto odds ratio 4.95, 95% confidence interval 2.18 to 11.24). Nine patients would need to be treated by an off-midline procedure to prevent one surgical site infection and 11 would need to be treated to prevent one recurrence.

CONCLUSIONS: Wounds heal more quickly after primary closure than after open healing but at the expense of increased risk of recurrence. Benefits were clearly shown with off-midline closure compared with midline closure. Off-midline closure should become standard management for pilonidal sinus when closure is the desired surgical option.