Pilonidal sinus disease

Pilonidal sinus disease – PITS studie

– The ninth Dutch Snapshot study –

Participating centers

10th of November 2021


10th of November 2021


Pilonidal sinus disease is an infected subcutaneous tract in the intergluteal fold that is responsible for around 8000 operations in the Netherlands annually. Many types of surgical treatment exist but a lack of comparative studies of these therapies, considering disease severity, have led to a varied practice in the Netherlands. Common surgical practice is based on low-level scientific evidence, expert opinion and the surgeons own experience.

Study population

Patients aged 16 years or older with symptomatic pilonidal sinus disease for which surgery is performed.


To perform a national audit of the surgical management of pilonidal sinus disease.


Primary endpoint is an overview of the different pilonidal sinus disease subtypes, types of surgical treatment and frequency of performance. Secondary endpoints are time until healing, percentage of non-healing wounds, percentage of recurrence, experienced pain, quality of life, risk factors for failed therapy, average time to resume daily activity, complications, patient experience and economic evaluation.

Study design

Study design
National prospective multicenter observational cohort study.


All Dutch hospitals and proctology clinics have been invited to participate in this nationwide snapshot study. Every month a group of hospitals will start including patients once the study has been approved by their local Board of Directors. For a period of 3 months patients will be included in the study. This proposed period may be extended if hospitals need to downscale their operations due to the corona crisis. The first centers have started in January 2021 and currently 40 centers are including patients.

Other projects

Eleven other projects are performed by the Dutch Snapshot Research Group.

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Study website

Read more about the PITS studie on

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