Pilonidal SinusENVELOPNCT06647290
ENVELOP: Wound Care Following Pilonidal Sinus Surgery
A study testing Negative Pressure Wound Therapy and Standard wound care in people with Pilonidal Sinus and Wound Healing, run by Royal College of Surgeons, Ireland at 10 sites in Ireland.
Trial summary
This is a single-blinded, multicentre, prospective randomised controlled trial (RCT) comparing post-operative and patient-reported outcomes for patients undergoing application of negative-pressure wound therapy (NPWT) after sinus tract excision as compared to excision and standard open wound care in chronic pilonidal… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Pilonidal Sinus, Wound Healing
- What is being tested?
- Negative Pressure Wound Therapy and Standard wound care
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 200 participants
- Where
- 10 sitesIreland
- Study dates
- 1 Oct 2024to Jun 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- They are aged 18 years or older
- They are undergoing elective pilonidal sinus excision without primary closure
Who cannot join
- They are unable to adhere to protocol requirements e.g. questionnaire completion
- They are undergoing emergency drainage for a pilonidal abscess
- They are undergoing surgery for pilonidal sinus disease in locations other than the natal cleft
- They have underlying osteomyelitis
- They have underlying fistulating disease e.g. Crohn's
Trial locations and contacts
10 sites in 1 country. Contact the study team or a site near you to ask about taking part.
10 sites in 1 country
Ireland10 sites, 10 recruiting
- Recruiting
Mayo University Hospital
Castlebar
Kevin Barry
- Recruiting
Beaumont Hospital
Dublin, D09V2N0
John Burke
- Recruiting
St James's Hospital
Dublin
Michael Kelly
- Recruiting
St Michael's Hospital, Dún Laoghaire
Dublin
Helen Heneghan
- Recruiting
St Vincent's Univeristy Hospital
Dublin
Eanna Ryan
- Recruiting
Tallaght University Hospital
Dublin
Dara Kavanagh
- Recruiting
St. Luke's Hospital
Kilkenny
Cathy Cronin
- Recruiting
University Hospital Limerick
Limerick
Colin Peirce
- Recruiting
Midlands University Hospital
Tullamore
Sean Johnston
- Recruiting
University Hospital Waterford
Waterford
Peter Neary
About this study
Official title: Excision and Negative Pressure Wound Therapy Versus Excision and Leaving Open With Standard Wound Care for Management of Chronic Pilonidal Sinus Disease - A Randomised Controlled Trial
This is a single-blinded, multicentre, prospective randomised controlled trial (RCT) comparing post-operative and patient-reported outcomes for patients undergoing application of negative-pressure wound therapy (NPWT) after sinus tract excision as compared to excision and standard open wound care in chronic pilonidal sinus disease (PSD).
Read the detailed description
Pilonidal sinus disease (PSD) is a chronic inflammatory condition of the skin and subcutaneous tissues arising from hair follicles in the natal cleft. The definitive aetiology of the condition is unknown, however, it is theorised that it is the result of either the obstruction and subsequent inflammation of hair follicles or secondary to hair penetrating through the skin into the subcutaneous tissue. This results in infection, abscess formation, chronic discharge and pain. PSD is a common condition affecting 26 per 10,000 population, with the prevalence reaching 1.1% in young adult males.
PSD causes a significant burden on healthcare services due to high rates of recurrence and readmission following surgery, together with negative impacts on patients' quality of life and self-image. An effective management strategy for the disease is necessary to ensure that post-operative outcomes are optimised and patient-reported outcomes are satisfactory in those whose PSD requires surgery.
The objective of this multicentre, national RCT is to prospectively investigate the effect of negative pressure wound therapy compared to leaving open with standard wound care on time to wound healing following surgical excision of chronic PSD.
- Conditions
- Pilonidal Sinus, Wound Healing
- Being tested
- Negative Pressure Wound Therapy, Standard wound care
- Keywords
- Negative Pressure Wound Therapy, Surgical Site Infection, Post-operative Complications, Health Economics, POSAS, CoPaQ, EQ-5D-5L, Pain Score
- Medical subject headings
- Pilonidal Sinus, Surgical Wound Infection
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Negative Pressure Wound TherapyDevice
Following elective excision of chronic pilonidal sinus disease with the wound left open, NPWT is applied in theatre using a polyurethane foam-based system (e.g. VAC, Renasys-GO, Prevena or equivalent) cut to fit the wound cavity, sealed with an adhesive drape and connected to a portable pump at -125 mmHg continuous pressure. Dressings are changed every 48-72 hours in clinic until granulation reaches skin level, followed by standard dressings until epithelialisation.
Standard wound careOther
Standard wound care
| Study group | Role | What they receive |
|---|---|---|
| Negative Pressure Wound Therapy | Experimental | The wound is dressed using negative pressure wound therapy. Receives: Device: Negative Pressure Wound Therapy |
| Standard wound care (SWC) | Active comparator | Following excision, the wound is left open (no primary closure) and managed with standard dressings according to local protocol, with wound healing by secondary intention. Receives: Other: Standard wound care |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time to complete wound healing
Number of days to complete epithelialisation or closure of the wound without any discharge, drainage, scab, and/or the requirement for further dressing.
Measured: Up to 6 months post surgery
Secondary outcomes (7)
Measure of post operative pain
Pain measured by visual analogue pain scale (0 = no pain, 10 = worst pain) at rest, on walking and on sitting
Measured: Day of surgery, 28 days post surgery & 3 months post surgery
Measure of post operative complications
Post-operative complications, including surgical site infection (CDC criteria), seroma, abscess, readmission and return to theatre.
Measured: 6 months post surgery
To compare recurrence rates
To compare the 6-month recurrence rates (recurrence being defined as the development of a new sinus or abscess within the natal cleft occurring after wound healing had been achieved) between the NPWT and SWC Groups
Measured: 6 months post surgery
Cost-effectiveness
Within-trial cost-utility analysis from health-system and patient perspectives, expressed as incremental cost per QALY gained (QALYs from EQ-5D-5L, area under the curve). Resource use includes hospital and community contacts, dressing changes, complications, readmissions and returns to theatre, valued at Irish unit costs; patient costs and productivity losses via CoPaQ.
Measured: 6 months post surgery
Health-related quality of life with the EuroQol-5 dimensions five level index questionnaire (EQ-5D-5L)
The questionnaire covers five dimensions of health: mobility, self-care, usual activities, pain or discomfort, and anxiety or depression. Each dimension has 5 levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4) and extreme problems (5). The patient is asked to indicate his/her health state by ticking the box next to the most appropriate statement in each of the five dimensions. Index values derived using the EQ-5D-5L value set specified in the Statistical Analysis Plan (Irish value set where available).
Measured: Baseline, 1 month, 3 months & 6 months
Scar assessment - using the Patient and Observer Scar Assessment Scale (POSAS)
The POSAS is made up of two scales: the patient and observer scales each comprise six items scored 1 to 10; each scale is summed (6 = normal, 60 = worst) and reported separately.
Measured: 28 days, 3 months, 6 months
Health-related out-of- Pocket Costs assessed using the Costs for Patients Questionnaire (CoPaQ)
The CoPaQ measures patient and caregivers out-of-pocket expenses (direct and indirect) associated with a health condition
Measured: 28 days, 3 months, 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Oct 2024
- Study start1 Oct 2024
- Primary completionDec 2026 (estimated)
- Study completionJun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pilonidal SinusStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Royal College of Surgeons, Ireland
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Sean T Martin, Principal investigator, St. James's Hospital, Ireland
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06647290
- Sponsor's protocol ID
- RCSI-ENVELOP
- Acronym
- ENVELOP
- Status last verified
- Jul 2026
- First submitted
- 28 Nov 2023
- Last updated
- 24 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Excision and Negative Pressure Wound Therapy Versus Excision and Leaving Open With Standard Wound Care for Management of Chronic Pilonidal Sinus Disease - A Randomised Controlled Trial
- ClinicalTrials.gov ID
- NCT06647290
- Acronym / sponsor ID
- ENVELOP / RCSI-ENVELOP
- Conditions
- Pilonidal Sinus, Wound Healing
- Keywords
- Negative Pressure Wound Therapy, Surgical Site Infection, Post-operative Complications, Health Economics, POSAS, CoPaQ, EQ-5D-5L, Pain Score
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Royal College of Surgeons, IrelandUniversity, hospital or other
- Study start
- 1 Oct 2024 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Jun 2027 (estimated)
- First posted
- 17 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a single-blinded, multicentre, prospective randomised controlled trial (RCT) comparing post-operative and patient-reported outcomes for patients undergoing application of negative-pressure wound therapy (NPWT) after sinus tract excision as compared to excision and standard open wound care in chronic pilonidal sinus disease (PSD).
Detailed description
Pilonidal sinus disease (PSD) is a chronic inflammatory condition of the skin and subcutaneous tissues arising from hair follicles in the natal cleft. The definitive aetiology of the condition is unknown, however, it is theorised that it is the result of either the obstruction and subsequent inflammation of hair follicles or secondary to hair penetrating through the skin into the subcutaneous tissue. This results in infection, abscess formation, chronic discharge and pain. PSD is a common condition affecting 26 per 10,000 population, with the prevalence reaching 1.1% in young adult males.
PSD causes a significant burden on healthcare services due to high rates of recurrence and readmission following surgery, together with negative impacts on patients' quality of life and self-image. An effective management strategy for the disease is necessary to ensure that post-operative outcomes are optimised and patient-reported outcomes are satisfactory in those whose PSD requires surgery.
The objective of this multicentre, national RCT is to prospectively investigate the effect of negative pressure wound therapy compared to leaving open with standard wound care on time to wound healing following surgical excision of chronic PSD.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Negative Pressure Wound Therapy | Experimental | Device: Negative Pressure Wound TherapyThe wound is dressed using negative pressure wound therapy. |
| Standard wound care (SWC) | Active comparator | Other: Standard wound careFollowing excision, the wound is left open (no primary closure) and managed with standard dressings according to local protocol, with wound healing by secondary intention. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- They are aged 18 years or older
- They are undergoing elective pilonidal sinus excision without primary closure
Key exclusion criteria (5 listed)
- They are unable to adhere to protocol requirements e.g. questionnaire completion
- They are undergoing emergency drainage for a pilonidal abscess
- They are undergoing surgery for pilonidal sinus disease in locations other than the natal cleft
- They have underlying osteomyelitis
- They have underlying fistulating disease e.g. Crohn's
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Negative Pressure Wound TherapyFollowing elective excision of chronic pilonidal sinus disease with the wound left open, NPWT is applied in theatre using a polyurethane foam-based system (e.g. VAC, Renasys-GO, Prevena or equivalent) cut to fit the wound cavity, sealed with an adhesive drape and connected to a portable pump at -125 mmHg continuous pressure. Dressings are changed every 48-72 hours in clinic until granulation reaches skin level, followed by standard dressings until epithelialisation. | Device | Negative Pressure Wound Therapy |
| Standard wound careStandard wound care | Other | Standard wound care (SWC) |
Primary outcome
Time to complete wound healing
Time frame: Up to 6 months post surgery
Number of days to complete epithelialisation or closure of the wound without any discharge, drainage, scab, and/or the requirement for further dressing.
7 secondary outcomes
Measure of post operative pain
Time frame: Day of surgery, 28 days post surgery & 3 months post surgery
Measure of post operative complications
Time frame: 6 months post surgery
To compare recurrence rates
Time frame: 6 months post surgery
Cost-effectiveness
Time frame: 6 months post surgery
Health-related quality of life with the EuroQol-5 dimensions five level index questionnaire (EQ-5D-5L)
Time frame: Baseline, 1 month, 3 months & 6 months
Scar assessment - using the Patient and Observer Scar Assessment Scale (POSAS)
Time frame: 28 days, 3 months, 6 months
Health-related out-of- Pocket Costs assessed using the Costs for Patients Questionnaire (CoPaQ)
Time frame: 28 days, 3 months, 6 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Sep 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Sean T Martin principal investigator
St. James's Hospital, Ireland
10 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Negative Pressure Wound Therapy and Standard wound care in people with Pilonidal Sinus and Wound Healing, run by Royal College of Surgeons, Ireland at 10 sites in Ireland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 24 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 10 sites in Ireland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sean T Martin ((01) 261 4037, seanmartin@rcsi.ie), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time to complete wound healing (time frame: Up to 6 months post surgery). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Sep 2026.