Bottom Line

Limited evidence suggested that platelet-rich plasma, Lietofix cream and hydrogel dressings may benefit wound healing following surgical treatment for sacrococcygeal pilonidal sinus. These findings are likely to be reliable.

Risk of Bias Assessment

Overall summary Low risk of bias in the review

All domains are rated low risk. Identified studies were relevant to the research question and reviewers did not emphasise results on the basis of their statistical significance.

A. Did the interpretation of findings address all of the concerns identified in Domains 1 to 4?	Probably yes
B. Was the relevance of identified studies to the review's research question appropriately considered?	Probably yes
C. Did the reviewers avoid emphasizing results on the basis of their statistical significance?	Probably yes
Risk of bias in the review	Low

Details of Review

Results

Two studies compared topical negative pressure wound therapy (TNPWT) with conventional open wound healing whilst the remaining nine studies compared different passive
dressings (two studies compared platelet-rich plasma with sterile absorbent gauze, and the other seven studies compared various dressings and topical agents). It is unclear whether TNPWT reduces time to wound healing compared with conventional open wound healing. Lietofix cream may increase the proportion of wounds that heal by 30 days compared with an iodine dressing. It was unclear whether hydrogel dressings reduce time to wound healing compared with wound cleaning with 10% povidone iodine or whether gentamicin-impregnated collagen sponge reduces time to wound healing compared with no dressing. Platelet-rich plasma may reduce time to wound healing compared with sterile absorbent gauze. Zinc oxide mesh may make little or no difference to time to wound healing compared with placebo while dialkylcarbamoyl chloride (DACC)-coated dressings may make little or no difference to time to wound healing compared with alginate dressings. It is unclear whether polyurethane foam hydrophilic or alginate dressing has any effect on time to wound healing.

Full Risk of Bias Assessment

Domain 1: Study Eligibility Criteria Low

The review adhered to objectives and eligibility criteria outlined in the introduction and methods sections. Eligibility criteria were well-defined and appropriate for the review question. No inappropriate restrictions in eligibility criteria were imposed based on study characteristics or sources of information.

1.1 Did the review adhere to pre-defined objectives and eligibility criteria?	Probably yes
1.2 Were the eligibility criteria appropriate for the review question?	Probably yes
1.3 Were eligibility criteria unambiguous?	Probably yes
1.4 Were all restrictions in eligibility criteria based on study characteristics appropriate (e.g. date, sample size, study quality, outcomes measured)?	Probably yes
1.5 Were any restrictions in eligibility criteria based on sources of information appropriate (e.g. publication status or format, language, availability of data)?	Probably yes
Concerns regarding specification of study eligibility criteria	Low

Domain 2: Identification and Selection of Studies Low

Cochrane Wounds Specialised Register, CENTRAL, MEDLINE, Embase and EBSCO CINAHL Plus were searched. Clinical trials registries (ClinicalTrials.gov and International Clinical Trials Registry Platform), reference lists of included studies, reviews, meta-analyses and health technology reports were searched for additional articles. The terms and structure of the search strategy were adequate. No restrictions on language, date of publication or study setting were imposed during the search. Two authors were involved in study selection.

2.1 Did the search include an appropriate range of databases/electronic sources for published and unpublished reports?	Probably yes
2.2 Were methods additional to database searching used to identify relevant reports?	Probably yes
2.3 Were the terms and structure of the search strategy likely to retrieve as many eligible studies as possible?	Probably yes
2.4 Were restrictions based on date, publication format, or language appropriate?	Probably yes
2.5 Were efforts made to minimise error in selection of studies?	Probably yes
Concerns regarding methods used to identify and/or select studies	Low

Domain 3: Data Collection and Study Appraisal Low

Two authors were involved in data collection and study appraisal. Sufficient study characteristics were considered to allow for interpretation of the results. Relevant study results were collected for use in the synthesis. Cochrane tool for assessing risk of bias was used for assessment of methodological quality of included studies.

3.1 Were efforts made to minimise error in data collection?	Probably yes
3.2 Were sufficient study characteristics considered for both review authors and readers to be able to interpret the results?	Probably yes
3.3 Were all relevant study results collected for use in the synthesis?	Probably yes
3.4 Was risk of bias (or methodological quality) formally assessed using appropriate criteria?	Probably yes
3.5 Were efforts made to minimise error in risk of bias assessment?	Probably yes
Concerns regarding methods used to collect data and appraise studies	Low

Domain 4: Synthesis and Findings Low

All relevant identified studies were included in the synthesis. Departures from planned analyses were explained adequately. Method of analyses was explained and appeared appropriate. There was significant heterogeneity for some outcomes, but this could not be explored further due to the limited number of included studies. Fewer than ten studies were included in each meta-analysis, therefore sensitivity analyses were not applicable. Biases in primary studies were considered in the synthesis.

4.1 Did the synthesis include all studies that it should?	Probably yes
4.2 Were all pre-defined analyses reported or departures explained?	Probably yes
4.3 Was the synthesis appropriate given the degree of similarity in the research questions, study designs and outcomes across included studies?	Probably yes
4.4 Was between-study variation minimal or addressed in the synthesis?	Probably yes
4.5 Were the findings robust, e.g. as demonstrated through funnel plot or sensitivity analyses?	Probably yes
4.6 Were biases in primary studies minimal or addressed in the synthesis?	Probably yes
Concerns regarding synthesis and findings	Low

Abstract

Abstract - Background Sacrococcygeal pilonidal sinus disease is a common debilitating condition that predominantly affects young adults, with a profound impact on their activities of daily living. The condition is treated surgically, and in some cases the wound in the natal cleft is left open to heal by itself. Many dressings and topical agents are available to aid healing of these wounds. Objectives To assess the effects of dressings and topical agents for the management of open wounds following surgical treatment for sacrococcygeal pilonidal sinus in any care setting. Search methods In March 2021, we searched the Cochrane Wounds Specialised Register, CENTRAL, MEDLINE, Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and we scanned reference lists of included studies, reviews, meta‐analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting. Selection criteria We included parallel‐group randomised controlled trials (RCTs) only. We included studies with participants who had undergone any type of sacrococcygeal pilonidal sinus disease surgery and were left with an open wound. Data collection and analysis We used the standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of the evidence for each outcome. Main results We included 11 RCTs comprising 932 participants. Two studies compared topical negative pressure wound therapy (TNPWT) with conventional open wound healing, two studies compared platelet‐rich plasma with sterile absorbent gauze, and the other seven studies compared various dressings and topical agents. All studies were at high risk of bias in at least one domain, whilst one study was judged to be at low risk of bias in all but one domain. All studies were conducted in secondary care. Mean participant ages were between 20 and 30 years, and nearly 80% of participants were male. No studies provided data on quality of life, cost‐effectiveness, pain at first dressing change or proportion of wounds healed at 6 or 12 months, and very few adverse effects were recorded in any study. It is unclear whether TNPWT reduces time to wound healing compared with conventional open wound healing (comparison 1), as the certainty of evidence is very low. The two studies provided conflicting results, with one study showing benefit (mean difference (MD) −24.01 days, 95% confidence interval (CI) −35.65 to −12.37; 19 participants), whilst the other reported no difference. It is also unclear whether TNPWT has any effect on the proportion of wounds healed by 30 days (risk ratio (RR) 3.60, 95% CI 0.49 to 26.54; 19 participants, 1 study; very low‐certainty evidence). Limited data were available for our secondary outcomes time to return to normal daily activities and recurrence rate; we do not know whether TNPWT has any effect on these outcomes. Lietofix cream may increase the proportion of wounds that heal by 30 days compared with an iodine dressing (comparison 4; RR 8.06, 95% CI 1.05 to 61.68; 205 participants, 1 study; low‐certainty evidence). The study did not provide data on time to wound healing. We do not know whether hydrogel dressings reduce time to wound healing compared with wound cleaning with 10% povidone iodine (comparison 5; MD −24.54 days, 95% CI −47.72 to −1.36; 31 participants, 1 study; very low‐certainty evidence). The study did not provide data on the proportion of wounds healed. It is unclear whether hydrogel dressings have any effect on adverse effects as the certainty of the evidence is very low. Platelet‐rich plasma may reduce time to wound healing compared with sterile absorbent gauze (comparison 6; MD −19.63 days, 95% CI −34.69 to −4.57; 210 participants, 2 studies; low‐certainty evidence). No studies provided data on the proportion of wounds healed. Platelet‐rich plasma may reduce time to return to normal daily activities (MD −15.49, 95% CI −28.95 to −2.02; 210 participants, 2 studies; low‐certainty evidence). Zinc oxide mesh may make little or no difference to time to wound healing compared with placebo (comparison 2; median 54 days in the zinc oxide mesh group versus 62 days in the placebo mesh group; low‐certainty evidence). We do not know whether zinc oxide mesh has an effect on the proportion of wounds healed by 30 days as the certainty of the evidence is very low (RR 2.35, 95% CI 0.49 to 11.23). It is unclear whether gentamicin‐impregnated collagen sponge reduces time to wound healing compared with no dressing (comparison 7; MD −1.40 days, 95% CI −5.05 to 2.25; 50 participants, 1 study; very low‐certainty evidence). The study did not provide data on the proportion of wounds healed. Dialkylcarbamoyl chloride (DACC)‐coated dressings may make little or no difference to time to wound healing compared with alginate dressings (comparison 8; median 69 (95% CI 62 to 72) days in the DACC group versus 71 (95% CI 69 to 85) days in the alginate group; 1 study, 246 participants; low‐certainty evidence). One study compared a polyurethane foam hydrophilic dressing with an alginate dressing (comparison 3) whilst another study compared a hydrocolloid dressing with an iodine dressing (comparison 9). It is unclear whether either intervention has any effect on time to wound healing as the certainty of evidence is very low. Authors' conclusions At present, the evidence that any of the dressings or topical agents contained in this review have a benefit on time to wound healing, the proportion of wounds that heal at a specific time point or on any of the secondary outcomes of our review ranges from low certainty to very low certainty. There is low‐certainty evidence on the benefit on wound healing of platelet‐rich plasma from two studies and of Lietofix cream and hydrogel dressings from single studies. Further studies are required to investigate these interventions further. Plain language summary How effective are dressings and topical agents in the management of wounds after surgical treatment for pilonidal sinus of the buttocks? Key messages ‐ Platelet‐rich plasma (part of the participant's own blood that promotes tissue regeneration) may reduce time to wound healing compared with sterile gauze
‐ Lietofix skin repair cream may help wounds to heal by 30 days compared with a dressing with iodine (which helps to reduce bacteria in the wound)
‐ It is not clear whether hydrogel dressings (designed to keep the wound moist) reduce time to wound healing compared with wound cleaning with iodine What is pilonidal sinus disease of the buttocks? Pilonidal sinus disease of the buttocks is a common painful condition that mainly affects young adults. It occurs in the natal cleft (the groove between the buttocks). It begins as infected or inflamed hair follicles. A vacuum effect, created by the motion of the buttocks, may draw more hairs down into the inflamed area. Symptoms can be very painful and sometimes last for a long time. How is pilonidal sinus of the buttocks treated? The condition is often treated surgically, by cutting out the inflamed area containing the hair and debris, and in some cases the wounds are not closed by stitches but left open to heal naturally. A lot of dressings and topical agents (creams or lotions) are available to help these wounds heal. What did we want to find out? We wanted to see which dressings and topical agents are better for treating open wounds after surgical treatment for pilonidal sinus of the buttocks. For each intervention we looked at: ‐ how long it took wounds to heal;
‐ the number of wounds healed after 30 days, 6 months and 1 year;
‐ whether the wounds came back;
‐ how long it took people who had been treated to return to normal daily activities;
‐ quality of life;
‐ value for money;
‐ pain during the first dressing change;
‐ harmful effects (for example surgical site infection or allergic reaction) after treatment. What did we do? We included participants of any age and either sex who had been treated in any care setting. We searched for studies where: ‐ participants had been treated for pilonidal sinus disease of the buttocks and were left with an open wound;
‐ different dressings and topical agents were compared to see how effective they were for helping wounds to heal. What did we find? We included 11 studies with a combined total of 932 participants. Two studies compared topical negative pressure wound therapy (which applies controlled suction to the surface of the wound) with simple wound dressings. Two studies compared platelet‐rich plasma with sterile absorbent gauze. The other seven studies compared various dressings and topical agents. All the studies took place in hospitals. ‐ No studies provided data on quality of life, value for money or pain at the first dressing change.
‐ We do not know if topical negative pressure wound therapy helps wounds to heal faster than simple wound dressings.
‐ Lietofix skin repair cream may help wounds to heal by 30 days.
‐ We do not know if hydrogel dressings help wounds to heal faster or protect better against surgical site infection compared with wound cleaning with 10% povidone iodine.
‐ Platelet‐rich plasma may reduce the time to wound healing compared with sterile absorbent gauze. 
‐ Compared with placebo mesh, mesh with zinc oxide (which is thought to have healing properties) may have little or no effect on whether wounds heal by 30 days, and it is unclear if it reduces the time to wound healing.
‐ We do not know if collagen sponge soaked in antibiotic has any effect on the time to wound healing compared with no dressing.
‐ Dressings coated with dialkylcarbamoyl chloride (a substance that bacteria sticks to) may make little to no difference to wound healing time compared with alginate dressings (derived from seaweed). What are the limitations of the evidence? We are not very confident in the evidence because there were only one or two studies in each comparison and most of the studies were very small. It is also possible that people in the studies were aware of what treatment they were getting. How up to date is this evidence? The evidence in this review is up to date to March 2021.