Treatment Outcomes of Presacral Pilonidal Sinus Disease Using Crystallised Phenol: A Single-Centre Clinical Series

To evaluate short-term treatment outcomes and treatment burden in patients with presacral pilonidal sinus disease managed with crystallised phenol in a single-centre clinical series, with particular emphasis on the relationship between pit burden and session requirement.

Consecutive patients treated with crystallised phenol were analysed (n = 40). Demographic and clinical characteristics, symptom duration, pit count, number of phenol sessions (2 vs. 3), inter-session intervals, and total treatment duration were recorded. All patients completed scheduled clinical reassessment at 5 weeks and 3 months. Treatment-related abscess and recurrence during follow-up were documented. Continuous variables are presented as mean ± standard deviation and median (minimum-maximum). Comparisons between the two-session and three-session groups were performed with the Mann-Whitney U test for continuous variables and Fisher's exact test for categorical variables.

The cohort was predominantly male (75%), with a mean age of 29.23 ± 9.85 years and a mean body mass index of 25.81 ± 3.85 kg/m²; 62.5% were smokers. Symptom duration was 6.80 ± 7.20 months, and mean pit count was 1.90 ± 0.93. Two sessions were sufficient in 42.5% (17/40), whereas 57.5% (23/40) required three sessions. The interval between the first and second sessions was 11.32 ± 3.30 days, and the interval between the second and third sessions was 11.96 ± 3.23 days in patients who underwent three sessions; overall treatment duration was 18.2 ± 7.58 days. No patient was lost to follow-up. Pit burden was the strongest determinant of requiring a third session: pit count was significantly higher in the three-session group than in the two-session group (2.39 ± 0.89 vs. 1.24 ± 0.44, p < 0.001), and all patients with ≥ 3 pits required three sessions. Smoking status (p = 1.000) and body mass index (BMI) (p = 0.208) were not associated with session requirement. Treatment-related abscess developed in 12.5% (5/40), and recurrence during the 3-month follow-up was observed in 12.5% (5/40); notably, all such events occurred in the three-session group (0/17 vs. 5/23, p = 0.061 for both comparisons).

In this single-centre series, crystallised phenol provided acceptable short-term outcomes and a relatively short treatment course in presacral pilonidal sinus disease. Pit count emerged as the main determinant of requiring a third session, whereas smoking status and BMI were not associated with session requirement. Larger studies with longer follow-up are needed to clarify predictors of recurrence and to determine whether higher session requirements simply reflect disease complexity or also influence outcome.