Timeline of recurrence after primary and secondary pilonidal sinus surgery.

PURPOSE: This study was designed to evaluate the timeline of recurrence of pilonidal sinus disease after primary vs. multiple surgery. Data of medical military service in Germany were reviewed.
METHODS: Telephone interview of 205 patients after pilonidal sinus disease surgery after median interval of 14.8 (standard deviation +/-3.9) years was conducted. A total of 345 patient charts with pilonidal sinus disease recurrence and fully documented previous surgery history were analyzed.
RESULTS: Pilonidal sinus disease recurred in 41 of 205 patients (20 percent; actuarial survival 22 percent) after first surgery. Median recurrence-free-interval was 1.8 (range, 0.1-16.5) years. Twenty-nine of 41 of all recurrences (71 percent) were observed within four years after primary surgery. Fifteen of 50 patients (30 percent) treated by primary closure had recurrent disease after a median recurrence-free interval of 2.7 (range, 0.2-13.5) years compared with 24 of 144 patients (17 percent), who experienced recurrence after rhomboid excision and open wound treatment after a median of 1.8 (range 0.1-16.5) years (P = 0.081, long-rank-test). Analysis of 345 recurrent disease charts revealed that recurrence time decreased for multiple recurrences compared with first recurrence (R1 vs. R2: P = 0.07; R2 vs. R3: P = 0.03, Mann-Whitney U test).
CONCLUSIONS: Long-term recurrence rate was 22 percent and thus higher than previously reported. This may be attributed to the long follow-up interval. Recurrences up to 20 years after surgery were seen. Our data provide evidence that follow-up after first to the third pilonidal sinus surgery should complete or exceed five years, because the majority of recurrences occur during this postoperative interval. Nevertheless, even a five-year follow-up will still miss 25 percent of recurrences.