Key messages
• Closing wounds from one side of the butt crack (off-midline closure) may lead to faster healing, lower chances of the disease returning, fewer infections, less chance of the wound breaking open again, shorter hospital stays, quicker return to work, and less pain compared to closing wounds directly from the middle of the butt crack (conventional midline closure).
• We could not find enough good-quality evidence to show that off-midline closure is better than closing wounds from the middle of the butt crack using special methods to reduce tension on the wound edges (tension-free midline closure).
• Larger, well‐designed studies are needed to give better estimates of the benefits and potential harms of the various midline and off-midline wound closure techniques for pilonidal sinus in both children and adults.
What is pilonidal sinus, and how can it be treated?
Pilonidal sinus disease is a condition where hairs get trapped in a tiny tunnel in the skin, usually near the top of the butt crack. It mostly affects young adults and can cause different symptoms, from no symptoms to significant pain. Surgery to remove the tunnel and surrounding skin is the main treatment for long-lasting (chronic) pilonidal sinus.
Closing the surgical wound from the middle of the butt crack is called midline closure. In conventional midline closure, the wound is directly closed in the middle of the butt crack. In tension-free midline closure, special methods are used to reduce tension on the wound edges.
Closing the wound from one side of the butt crack is called off-midline closure. There are many methods for off-midline closure, including various flap methods. These use a flap of skin to cover the area where tissue has been removed. Therefore, in this review, unless otherwise specified, the flaps mentioned are one of the off-midline closure methods.
What did we want to find out?
We wanted to find out:
• how well do the different methods of closing wounds work for treating pilonidal sinus?
• how well do different off-midline methods of closing wounds work for treating pilonidal sinus?
We wanted to find out how different methods of closing wounds affect:
• the time for wounds to heal completely;
• the proportion of people whose wounds heal completely;
• the proportion of pilonidal sinus recurrence;
• the proportion of wound infection;
• the proportion of people who had a wound breaking open again (wound dehiscence);
• the time to return to work;
• quality of life after surgery.
What did we do?
We searched for studies that investigated off-midline closure compared to conventional or tension-free midline closure, and studies that compared different types of off-midline closure. We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We found 33 studies that involved a total of 3667 people. The median or average age of the people in the studies ranged from 21 to 34 years. Most were men. The studies were primarily conducted in the Middle East. We identified 9 comparisons. In this summary, we present the results of the 3 main comparisons:
Off-midline closure versus conventional midline closure
• Off-midline closure probably causes a large reduction in time for wounds to heal completely, reduces the recurrence of pilonidal sinus, and reduces wound infections.
• Off-midline closure may cause a large reduction in wound dehiscence and a quicker return to work.
• Off-midline closure may have little to no effect on the proportion of people whose wounds heal completely, but we are very uncertain about the results.
Off-midline closure versus tension-free midline closure
• Off-midline closure may cause a large reduction in time for wounds to heal completely, may increase the proportion of people whose wounds heal completely at 3 months, and may increase the time to return to work.
• Off-midline closure may have little to no effect on the recurrence of pilonidal sinus, wound infections, and wound dehiscence.
Karydakis flap versus Limberg flap
• The Karydakis flap probably has little to no effect on time for wounds to heal completely, the recurrence of pilonidal sinus, wound infections, wound dehiscence, and time to return to work when compared to the Limberg flap.
What are the limitations of the evidence?
Our confidence in the findings was limited by poor study design, a small number of cases in the included studies, not enough studies to draw definitive conclusions, and a lack of data on certain outcomes in some studies.
The results of further research could differ from some results of this review.
How up to date is this evidence?
The evidence is current to June 2022.
This Cochrane review examines the midline and off-midline wound closure options for pilonidal sinus, predominantly based on young adult studies. Off-midline flap procedures demonstrate there may be benefits over conventional midline closure for pilonidal sinus, with various off-midline flap techniques. When off-midline flap closures were compared to tension-free midline closure, low-certainty evidence indicated there may be improved wound healing and increased time to return to work for off-midline closure, whilst very low-certainty evidence indicated there may be no evidence of a difference in other outcomes. There may be no evidence of an advantage found amongst the off-midline techniques evaluated. The choice of either procedure is likely to be based on a clinician's preference, experience, patient characteristics, and the patients' preferences. To more accurately determine the benefits and potential harms of these closure techniques, further large-scale and meticulously-designed trials are essential. Specifically, there is a pressing need for more studies addressing the paediatric population, in addition to adult studies.
Pilonidal sinus disease is a common and debilitating condition. Surgical treatment remains the mainstay for managing chronic disease, with options including midline and off-midline wound closure methods. However, the optimal approach remains uncertain. Recent developments in tension-free midline techniques require further exploration.
To assess the effects of midline and off-midline wound closure methods for pilonidal sinus, and to determine the optimal off-midline flap procedures.
In June 2022, we searched the Cochrane Wounds Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL Plus EBSCO, and clinical trials registries. We also scanned the reference lists of included studies, as well as reviews, meta‐analyses, and health technology reports. We applied no language, publication date, or study setting restrictions.
We included parallel RCTs involving participants undergoing midline closure without flap techniques and off-midline closure for pilonidal sinus treatment. We excluded quasi-experimental studies and studies that enroled participants presenting with an abscess.
We followed standard Cochrane methodology. The critical outcomes included wound healing (time to wound healing, proportion of wounds healed), recurrence rate, wound infection, wound dehiscence, time to return to work, and quality of life. We assessed biases in these outcomes utilising the Cochrane risk of bias 2 tool and appraised evidence certainty via the GRADE approach.
We included 33 studies with 3667 analysed participants. The median or average age of the participants across the included studies ranged from 21.0 to 34.2 years, with a predominant male representation. Geographically, the trials were primarily conducted in the Middle East. We identified nine intervention comparisons. In this abstract, we focus on and present the summarised findings for the three primary comparisons.
Off-midline closure versus conventional midline closure
Off-midline closure probably reduces the time to wound healing (mean difference (MD) -5.23 days, 95% confidence interval (CI) -7.55 to -2.92 days; 3 studies, 300 participants; moderate-certainty evidence). However, there may be little to no difference between the two methods in the proportion of wounds healed (100% versus 88.5%, risk ratio (RR) 1.13, 95% CI 0.92 to 1.39; 2 studies, 207 participants; very low-certainty evidence). Off-midline closure probably results in lower rates of recurrence (1.5% versus 6.8%, RR 0.22, 95% CI 0.11 to 0.45; 13 studies, 1492 participants; moderate-certainty evidence) and wound infection (3.8% versus 11.7%, RR 0.32, 95% CI 0.22 to 0.49; 13 studies, 1568 participants; moderate-certainty evidence), and may lower rates of wound dehiscence (3.9% versus 8.9%, RR 0.44, 95% CI 0.27 to 0.71; 11 studies, 1389 participants; low-certainty evidence). Furthermore, off-midline closure may result in a reduced time to return to work (MD -3.72 days, 95% CI -6.11 to -1.33 days; 6 studies, 820 participants; low-certainty evidence). There were no data available for quality of life.
Off-midline closure versus tension-free midline closure
Off-midline closure may reduce the time to wound healing (median 14 days in off-midline closure versus 51 days in tension‐free midline closure; 1 study, 116 participants; low‐certainty evidence) and increase wound healing rates at three months (94.7% versus 76.4%, RR 1.24, 95% CI 1.06 to 1.46; 1 study, 115 participants; low‐certainty evidence), but may result in little to no difference in rates of recurrence (5.4% versus 7.8%, RR 0.69, 95% CI 0.30 to 1.61; 6 studies, 551 participants; very low‐certainty evidence), wound infection (2.8% versus 6.4%, RR 0.44, 95% CI 0.16 to 1.17; 6 studies, 559 participants; very low‐certainty evidence), and wound dehiscence (2.5% versus 3.0%, RR 0.82, 95% CI 0.17 to 3.84; 3 studies, 250 participants; very low‐certainty evidence) compared to tension-free midline closure. Furthermore, off‐midline closure may result in longer time to return to work compared to tension‐free midline closure (MD 3.00 days, 95% CI 1.52 to 4.48 days; 1 study, 60 participants; low‐certainty evidence). There were no data available for quality of life.
Karydakis flap versus Limberg flap
Karydakis flap probably results in little to no difference in time to wound healing compared to Limberg flap (MD 0.36 days, 95% CI -1.49 to 2.22; 6 studies, 526 participants; moderate-certainty evidence). Compared to Limberg flap, Karydakis flap may result in little to no difference in the proportion of wounds healed (80.0% versus 66.7%, RR 1.20, 95% CI 0.77 to 1.86; 1 study, 30 participants; low-certainty evidence), recurrence rate (5.1% versus 4.5%, RR 1.14, 95% CI 0.61 to 2.14; 9 studies, 890 participants; low-certainty evidence), wound infection (7.9% versus 5.1%, RR 1.55, 95% CI 0.90 to 2.68; 8 studies, 869 participants; low-certainty evidence), wound dehiscence (7.4% versus 6.2%, RR 1.20, 95% CI 0.41 to 3.50; 7 studies, 776 participants; low-certainty evidence), and time to return to work (MD -0.23 days, 95% CI -5.53 to 5.08 days; 6 studies, 541 participants; low-certainty evidence). There were no data available for quality of life.