The PITSTOP study

PIlonidal sinus Treatment: STudying the OPtions (PITSTOP): an observational cohort with nested mixed methods and qualitative design to investigate surgical options for the treatment of pilonidal sinus disease.



Pilonidal disease (PD) is a common condition that affects about 26/100,000 of the population, (predominantly young, working people).

It is an acquired disease resulting in obstruction of hair follicles in the natal cleft (the anatomical groove between the buttocks). Subsequent rupture of the follicles leads to abscess and sinus formation.

Emergency presentation of pilonidal abscess requires hospitalisation with incision and drainage of the abscess cavity. One in five patients represent with recurrent symptoms following emergency surgery. This picture of relapsing and remitting infections is typical of chronic PD.

The condition is relatively common and represents a significant burden to primary and secondary care in the NHS. 2012 Hospital Episode Statistics (HES) data reported 13,239 hospital admissions for PD.

At present, both emergency and the most common elective excisional surgical treatments leave large open wounds that take months to heal. Patients consequently require prolonged wound care from their community services.

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.

The ideal management of PD should be simple, safe, cost effective, easy to perform and lead to a rapid return to normal activities, with low rates of acute wound complications (including infection, seroma, haematoma), recurrence, and rapid wound healing.

These aims are not reliably delivered by current surgical practice and there is no consensus on how to manage based on disease characteristics.

The PITSTOP study

We propose a prospective cohort study to determine the sub types of pilonidal disease, to describe the various interventions, to engage with patients and to determine which outcomes they value and which interventions they prefer/do not prefer and to provide recommendations for further research.

Cohort study

The PITSTOP cohort study is an observational study that will collect data on individuals presenting with pilonidal sinus disease. It will aim to classify the various presentations and severity of the disease.

It will record the outcomes of various surgical techniques. It will also identify patient-specific disease features that might predict poor outcomes in each treatment group.

Qualitative interviews 

The study will also take a sample of patient and complete qualitative interviews to provide an overview of patient views and experiences of the treatment that they have chosen and received.

This will also include the views of patients on which interventions they would rather avoid and which outcomes they most value in regards to their treatment options.

Discrete choice experiment

A discrete choice experiment (DCE) is a method that is used in health economics in order to elicit patient preferences. In the DCE the patient is presented with hypothetical scenarios with different variables and they are asked to make trade-offs.

In this way we can see what patients value from their treatment. After the interviews are completed the DCE will be emailed to the participants to complete.

Consensus exercise 

A modified Nominal Group Technique consensus exercise will be undertaken with clinicians to identify front running interventions for specific clinical scenarios.

This study is funded by NIHR Health Technology Assessment (HTA 17/17/02). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

This study is sponsored by Sheffield Teaching Hospitals.

If you have any questions please contact Emily Strong on


PITSTOP protocol (PDF, 571KB)

PITSTOP survey (DOC, 30KB)

Central study staff





Professor Steven Brown  Chief Investigator Sheffield Teaching Hospitals NHS Foundation Trust
Emily Strong Research Assistant University of Sheffield
Daniel Hind CTRU Oversight University of Sheffield
Heather Dakin Trial Support Officer University of Sheffield





Catherine Winton Patient Representative  University of Sheffield 
Ryan Edridge Patient Representative University of Sheffield 
Jon Lund Consultant Surgeon  Derby Royal Infirmary
Daniel Hind Assistant Director  University of Sheffield 
Asha Senapati Consultant Surgeon  Portsmouth Hospital 
Jonathon Morton Consultant Surgeon  Addenbrookes Hospital 
Christine Moffatt Professor of Clinical Nursing Research University of Nottingham 
Farhat Din Consultant Surgeon  University of Edinburgh 
Matthew Lee Clinical Research Fellow (Registrar)  Sheffield Teaching Hospitals NHS Foundation Trust
Peter Vaughan-Shaw Clinical Research Fellow (Registrar) University of Edinburgh 
Philip Shackley Reader in Health Economics  University of Sheffield 
Mike Bradburn  Medical Statistician  University of Sheffield 
Ellen Lee Medical Statistician  University of Sheffield 


This study is funded by NIHR Health Technology Assessment (HTA 17/17/02). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

Sheffield Teaching Hospitals

Flagship institutes

The University’s four flagship institutes bring together our key strengths to tackle global issues, turning interdisciplinary and translational research into real-world solutions.