Standardized Classification System for Pilonidal Disease and Recurrence Rate after Treatment

Current classification systems for pilonidal disease do not objectively profile disease severity, limiting their clinical applicability. This study aimed to validate a novel pilonidal disease severity (PDS) staging system by testing its correlation with disease recurrence.

This was a prospective cohort study set at a high-volume, specialized pilonidal care center. All patients presenting with pilonidal disease were included. The main effector under study was PDS stage assigned at initial presentation. Secondary effector variables were an open wound greater than 1 cm on presentation (descriptor W) or previous surgical resection (descriptor R). The primary outcome was pilonidal disease recurrence at 1- and 2-year follow-up.

A total of 411 patients met criteria, with 212 and 206 patients completing 1- and 2-year follow-up, respectively. Among patients who completed 1-year follow-up, recurrence occurred in 0.0%, 2.3%, 8.3%, and 20.8% of patients with PDS stage 0, I, II, and III disease at initial presentation, respectively (log-rank test, p = 0.017). At 2 years, recurrence was noted in 0.0%, 4.8%, 12.7%, and 27.5% of patients with PDS stage 0, I, II, and III disease, respectively (log-rank test, p = 0.010). The presence of an open wound at initial presentation and previous surgical resection was not associated with risk of recurrence (W, p = 0.94; R, p = 0.98).

This study described the first staging system for pilonidal disease that correlates with risk of recurrence. On further external validation, the PDS staging system may be used both clinically to tailor treatment regimens to risk of disease recurrence and in research to standardize disease severity when comparing different therapeutic interventions.