Title: PIlonidal sinus Treatment: STudying the OPtions (PITSTOP)
Funder: Department of Health and Social Care

Abstract: DESIGN Observational cohort (n=800). Nested mixed method case-studies (n=20-25 patients). Discrete choice experiment (n=300 of cohort). Modified nominal group consensus exercise (n=40 surgeons, n=15 patients). SETTING 15 NHS Trusts. TARGET POPULATION Adults with symptomatic pilonidal sinus considered suitable for surgery. Classification by anatomy/pathology of pit & tracks. ELIGIBILITY CRITERIA Consecutive, consenting patients > 18 years with pilonidal sinus disease. Exclusions: asymptomatic, pregnant, unable to give consent, acute abscess. HEALTH TECHNOLOGIES BEING ASSESSED Common approaches to surgical excision & closure Excision - Minimal (pit excision) - Major (take the whole thing out) - Curettage (scraping out) Closure - No closure - Midline - Lateral - Flap - Glue - Phenol injection/ endoscopic directed therapy to obliterate track Although 18 combinations are theoretically possible, about 6 combinations are commonly used. CLINICAL & PATIENT REPORTED OUTCOMES at 6w & 6m Outcomes that have been identified by clinicians & patients are (1) Wound healing (complete closure of the skin with no residual drainage or symptoms); (2) Infection; (3) Recurrence; (4) Post-operative pain rating; (5) EQ-5D-5L; (6) Return to normal activities; (7) Interactions with primary care; (8) Satisfaction (6m). Additional assessment of EQ-5D-5L, recurrence, satisfaction at end of study (up to 30 months). SAMPLE SIZE IDEAL 2b study: aims to consent n=800 from m9 to m23. We anticipate this will result in approximately 100 participants per front running management strategy which will enable us to estimate proportions to a standard error of <=5%, & pain to within a standard error of 0.2 points of a 10 point scale, the latter assuming a standard deviation of 2 units. ANALYSIS Risk models that predict healing & recurrence will be built for each treatment pathway. Propensity score matching of patients (based on patient characteristics & pit anatomy/pathology at screening) will be used to estimate risk-adjusted outcomes for each treatment pathway. The findings from the quantitative + qualitative work will be used to identify gaps in knowledge & to inform possible routes for further research. QUALITATIVE RESEARCH Nested mixed method case substudy. Brief semi-structured interviews at baseline & 6 months to elicit decision making regarding surgery & outcome preferences (n=20-25). Sampling based on variation by pit anatomy & surgical technique. Inductive framework analysis & triangulation to CODE framework will be used. A discrete choice experiment will be designed & used to elicit patient preferred outcomes in the wider cohort (n=300). CONSENSUS Nominal group technique(1) to achieve consensus on front running procedures by disease characteristics (n=40 surgeons &15 patients) with stratified sampling to assure national representation. PROJECT TIMETABLE 37-month project. 9m setup; 15m recruitment; 6m follow-up; 6m close-out, analysis and write-up. 15 sites have agreed to participate. Based on audit data from Sheffield, with staggered centre initiation, ineligibility, refusal of consent, we anticipate avg 4.2 consents per centre per m. or >800 participants in 15m at 15 Trusts. Pilot study aims to recruit n=212 in 6m (amber light); success criterion – recruitment of n>/=212 in 6m (red light). TEAM EXPERTISE Complementary skills: Patients, surgeons, trialists, statisticians & qualitative research

Lay abstract: Pilonidal disease is a condition where hair follicles in the groove between the buttocks (the natal cleft) become blocked and can get inflamed. The condition may not cause problems at all but often leads to abscesses and infected discharging holes in the skin which are extremely uncomfortable. It tends to affect young patients and can severely impact on the ability to work and socialise. The ideal management of pilonidal disease should be simple, safe and easy to carry out. It should lead to a rapid return to normal activities, with low rates of infection and recurrence, and rapid wound healing. Finally it should not cost too much to perform. Although many surgical interventions exist no-one seems to know which interventions best meet these requirements and whether certain operations suit certain patients more than others. Surgeons favour different techniques based to a significant extent on training and experience and there is tremendous variation in practice within the UK. Some procedures result in lengthy healing times and long periods of incapacity. As the disease tends to affect young otherwise healthy adults, this prolonged need for dressings and general wound care impacts on education, work, intimacy and social life, pain, recurrent infection and fear of wound deterioration all severely affecting quality of life. In order to work out what are the optimal treatment options for this condition and what types of disease are better treated with the options available we need to -work out a way of classifying the disease. One person may have a different disease pattern to another and may benefit from a different type of operation compared with another. -find out what patients think are the most important outcomes after surgery and see if these can be measured easily, effectively and reliably. -using those outcomes that patients feel are best we can then compare the best operations directly in future trials. -work out how surgeons decide on particular operations and why one surgeon would favour one operation and another another. We plan to answer these questions by 1. Recording the surgical experience of a large group of patients with the condition who undergo treatment. 2. Interviewing patients about their treatment and subsequent recovery. 3. Bringing both patients and surgeons together in a large discussion group. 1. The recording of the experience of a large group of patients will include details of the patient and the disease, the type of surgery they undergo and the process of recovery including time to healing, need for nursing care and complications that may arise. This will allow us to identify what techniques are being carried out and whether some patient and disease characteristics are best treated by what operation. 2. Patient interviews will provide an overview of patient views and experiences and allow us to identify which treatments patients would rather avoid and which outcomes they most value. 3. Finally both patients and surgeons will be brought together to try to match various operations with various types of pilonidal disease and decide on future more detailed research where the best operations can be compared against each other.

Research activity codes: 7.3 MANAGEMENT AND DECISION MAKING
Health categories: SKIN