Home - PiloNERDs International

Leading Global Innovation in Pilonidal Disease Care

Uniting experts worldwide to transform research and treatment.

Who We Are: A Passionate Global Team

We’re PiloNERDs International — a passionate global network of doctors, researchers, and educators who truly care about pilonidal disease.

Our members come from hospitals and institutions across Europe and beyond, all driven by a shared love for great science and better patient care.

Built on teamwork, openness, and continuous progress, we bring together experts from many fields to spark innovation and boost education in pilonidal sinus research and treatment. Learn more about the team.

PiloNERDs-Anthem

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Driving Research, Inspiring Progress

Our Mission: Research That Matters

Our biggest mission?

To push forward research that really makes a difference for pilonidal sinus disease and related conditions. We’re excited to create a lively space for training, professional growth, and sharing ideas among healthcare providers everywhere. By joining forces nationally and internationally, we back events and projects that raise treatment standards, spread clear guidelines, and improve quality of care. In the end, we want to change medical practice by turning the latest discoveries into better care and advice for patients everywhere.

Here are some examples of our ongoing research interests.

Familial Trait of Axial Hair Force (Hax)

Status: Previous research demonstrates that patients with PSD exhibit higher axial hair force (Hax) compared with matched non-PSD controls. Evidence also indicates a familial predisposition in PSD patients. Research question: How is Hax distributed within families and across generations? Aim: To measure and characterise Hax across multiple generations in affected families.

Pictures 1 a/b: Hax-Testung; Electron microscopic photo of sharp hair tip

Perforation Resilience of Skin

Status: Sharp hair fragments are known to penetrate the skin and initiate PSD; elevated Hax may contribute to this process. Prior work (Karydakis, 1992) has suggested that reduced skin resilience may be a risk factor in pilonidal sinus disease. Research question: Is diminished skin resilience a contributing factor to PSD development? Aim: To develop and validate methods for testing skin resilience and to compare results between PSD patients and unaffected individuals.

Pictures 2 a/b: Measuring instrument, skin resilience testing

Assessment of the Quality of PSD Literature

Status: A substantial proportion of published work on pilonidal sinus disease (PSD) appears to lack substantive value. Research question: Has the quality of the global PSD literature changed over time? Aim: To identify, apply, and validate quality-assessment tools for evaluating both RCTs and non-RCTs in the PSD literature.

Picture 3 a/b: Newcastle-Ottawa-Scale; ROB Graph analysis of world literature

Research creates new knowlege and publications

Good reseach inevitabily leads to discoveries and creates knowledge. New and interesting findings are interesting for other doctors and medical personel worldwide, so publishing them to inform others is part of our mission.

Creativity and cooperation can make productivity thrive, as does team research. Please find enclosed a small list of publications of our PiloNERDs research just published in 2025. We don´t publish to become famous. It is the spirit of the common task that matters, and publications are the by-product. Every publication is accompanied by a small summary indicating what is new and thrilling.

PiloNERDs publications 2025 – Scrollbarer Bereich

PiloNERDs publications 2025 – with small summaries

(from 16.09.2025)

1. Ankersen J, Faurschou I, Hougaard T. H, Doll D, Oetzmann von Sochaczewski C, Sørensen M, et al. Long-term outcomes after cleft lift surgery for pilonidal sinus disease in post-pubertal adolescents: data from a prospective Danish cohort. Colorectal Disease. 2025;27(1):e17169. Significance of the work: This prospective Danish cohort study evaluates long-term outcomes after cleft lift surgery in post-pubertal adolescents with pilonidal sinus disease. The results indicate low recurrence rates and minimal complications, supporting the procedure’s effectiveness in this patient group.

2. Doll D. Kommentar zur ESCP-Leitlinie zur Behandlung der Pilonidalsinus-Erkrankung. coloproctology. 2025;47:154-6. Significance of the work: This commentary highlights important aspects of the ESCP guidelines for pilonidal sinus disease management. It criticizes the given recommendations for clinical practice based on current evidence.

3. Doll D, Faurschou IK, von Sochaczewski CO. The importance of updating background information in pilonidal sinus disease research: commentary on Darnis et al. depilation Find: Khubezov 2020; Allam 2020. 2025;40(1):166-7. Significance of the work: The authors stress the importance of continuously updating background information in pilonidal sinus disease research to ensure accuracy and relevance. The commentary criticizes earlier studies on depilation and calls for more rigorous methodologies.

4. Doll D, Haas S, Faurschou IK, Hackmann T, Braun-Muenker M, Oetzmann von Sochaczewski C. Unveiling Observation Bias in Pilonidal Sinus Disease Studies: A Comparative Analysis of Study Designs and Follow-Up Protocols. Polish Journal of Surgery. 2025;97(2):1-6. Significance of the work: The extent of observation bias in ROR studies compared to RCTs and non-RCTs was unknown. Analyzing the largest therapeutic cohort globally reveals ROR recurrence rates potentially deflated by three to fourfold relative to RCTs or non-RCT findings. Any return-on-recurrence situation should be avoided.

5. Doll D, Haas S, Faurschou IK, Hackmann T, Heitmann H, Braun-Münker M, et al. Pediatric pilonidal sinus disease: Recurrence rates of different age groups compared to adults. Surgery Open Science. 2025;23:50-6. Significance of the work: The study compares recurrence rates between pediatric and adult populations with pilonidal sinus disease. Age-specific differences were identified, suggesting tailored treatment and follow-up strategies for different age groups.

6. Doll D, Hackmann T, Haas S, Laurberg S, Pilonidal Network for Expertise R, Development. Evaluation of Outcomes for Karydakis Operation for Pilonidal Sinus Disease-Comparison of Original Reports With Later Results. World J Surg. 2025;49(3):584-9. Significance of the work: This evaluation of the Karydakis operation compares original outcome reports with later follow-up data. The study reveals discrepancies between the original Karydakis 73/92 works and the world literature.

7. Doll D, Maak M, Faurschou IK, Hackmann T, von Sochaczewski CO, Braun-Münker M, et al. Impact of surgical case load on recurrence rates in pilonidal sinus disease: a cross-study data synthesis. le+. 2025;40(126):1-17. Significance of the work: By synthesizing data across multiple studies, this research demonstrates that higher surgical case loads are associated with reduced recurrence rates in pilonidal sinus surgery. This suggests experience and volume impact surgical outcomes.

8. Doll D, Maak M, Seifert J. [Post-primary Limberg flap-A new approach in pilonidal sinus surgery]. Chirurgie (Heidelb). 2025;Epub. Significance of the work: A novel post-primary Limberg flap technique for pilonidal sinus surgery is introduced with preliminary evidence suggesting improved healing and reduced recurrence. The RR is low and plausible

9. Doll D, Ommer A, Oetzmann von Sochaczewski C, Safadi F. Sinus pilonidalis. Chirurgische Proktologie. 42025. p. 431-68. Significance of the work: This comprehensive review covers the pathophysiology, diagnostic approaches, and treatment options for pilonidal sinus disease. It provides an up-to-date synthesis of current knowledge to guide clinical decision-making.

10. Doll D, Seifert J, Brengelmann I, Kuntze M. The Relationship Between Sweat Response, BMI, and Physical Activity: Implications for Pilonidal Sinus Disease. Turkish Journal of Colorectal Disease. 2025;35(2):55-8. Significance of the work: This investigation explores the relationship between sweat response, BMI, and physical activity, examining their potential roles in pilonidal sinus disease pathogenesis.

11. Doll D, Seifert J, Maak M, Oetzmann von Sochaczewski C. One century of pilonidal sinus research: trends in study size and the declining share of randomized controlled trials. coloproctology. 2025;Epub:1-8. Significance of the work: An historical analysis of pilonidal sinus research trends reveals increasing study sizes but a decline in the proportion of randomized controlled trials. This shift may affect the quality and robustness of evidence over time.

12. Faurschou IK, Ankersen JL, Pedersen N, Sorensen MJ, Friis ML, Pedersen AG, et al. Gender-specific outcomes in pilonidal sinus disease: Female outcomes after cleft lift surgery in a large prospective Danish cohort. Colorectal Dis. 2025;27(2):1-8. Significance of the work: This large prospective cohort study examines gender-specific outcomes after cleft lift surgery, reporting favorable results for female patients. The findings suggest potential sex-related differences in disease course and treatment response. Female PSD patients seem to represent a subcategory of patients at higher risk of treatment failure and should be dealt with as such. Our study shows, that only few female patients initially present with the need for extensive surgery. A common occurrence of prolonged healing and recurrence, leads to a recommendation of minimal invasive approach when possible.

13. Maak M, Morsdorf P, Bari L, Braun-Munker M, Scharonow M, Orth M, et al. Intergluteal fold depth has no influence on pilonidal sinus disease development. 2025;41(2):130-4. Significance of the work: This study finds no significant influence of intergluteal fold depth on pilonidal sinus disease development in contrary to the Akinci 2009 study.

14. Oetzmann von Sochaczewski C, Heitmann H, Izbicka K, Braun-Münker M, Maak M, Doll D. Altersabhängige Veränderungen der axialen Haarfestigkeit in der Pathogenese des Pilonidalsinus. coloproctology. 2025;47(1):29-33. Significance of the work: Research into age-dependent changes in axial hair strength suggests these alterations may contribute to pilonidal sinus disease pathogenesis. The findings describe mechanical factors influencing disease onset at younger age.

15. Pedersen N, Faurschou I, Ankersen J, Sørensen M, Friis ML, Pedersen G. A, et al. Distinct recurrence patterns according to disease manifestation in pilonidal sinus disease treated with cleft lift surgery at 5 years' follow-up in a large prospective Danish cohort. Colorectal Dis. 2025;27(1):1-7. Significance of the work: Distinct recurrence patterns related to disease manifestation were identified in a five-year follow-up study of patients treated with cleft lift surgery. The results may inform personalized management and prognosis assessment.

16. Safadi MF, Doll D. Letter re: "Pathological Examination in Pilonidal Sinus Surgery: Evaluating Necessity and Cost-Effectiveness: A 10-Year Retrospective Analysis". Am Surg. 2025;91(4):664-5. Significance of the work: This letter discusses the necessity and cost-effectiveness of routine pathological examinations in pilonidal sinus surgery. Based on a 10-year retrospective analysis, it offers considerations for optimizing resource use without compromising care quality.

17. Corturillo G, Jovanovic M, Rohleder S, Heydweiller AC, Muensterer OJ, Doll D, Oetzmann von Sochaczewski C. Practice patterns of paediatric surgeons on treating pilonidal sinus disease - a national survey study. Int J Colorectal Dis. 2025;40:165. Significance of the work: The study describes the current approach to pilonidal sinus disease in children and adolescents by German paediatric surgeons. Based on the responses of 40 paediatric surgical institutions, it found that they prefer traditional surgical approaches to the disease, but pit-picking was gaining ground.

18. Doll D, Haas S, Faurschou IK, Hackmann T, Heitmann H, Braun-Münker M, Oetzmann von Sochaczewski C. Pediatric pilonidal sinus disease: Recurrence rates of different age groups compared to adults. Surg Open Sci. 2025;23:50-56. Significance of the work: The study used the available literature to assess the recurrence rates of paediatric patients in comparison to adults. Paediatric pilonidal sinus patients had substantially increased recurrence rates compared to adults and recurrences occur earlier than in adults.

19. Oetzmann von Sochaczewski C, Hackmann T, Heitmann H, Braun-Münker M, Maak M, Doll D. Pilonidal Sinus Recurrence Rates in Young Adults—Similar to Children or Adults? Surgeries. 2025;6:60. Significance of the work: Based on tendencies in the literature to expand treatment concepts for children and adolescents to young adults, the study investigated whether recurrence rates and temporal distribution of recurrences of young adults would follow those of adults or those of paediatric patients. It found that pilonidal sinus disease in young adults follow the same recurrence dynamics as in adults.

(publications from January to August 2025)

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