Prognostic factors of flap techniques for pilonidal disease based on magnetic resonance imaging and clinical parameters

BACKGROUND: Postoperative complications and recurrence are major diffficulties in the flap techniques for the treatment of pilonidal sinus (PS), however, the risk factors remain unclear. While magnetic resonance imaging (MRI) offers the highest soft tissue resolution, few studies have applied MRI to investigate the basic parameters of PS. METHODS: A total of 100 patients receiving Limberg flap (LF) or Karydakis flap (KF) surgery at the Sixth Affiliated Hospital of Sun Yat-Sen University were retrospectively analyzed, and the median follow-up period was 42 (range, 20-90) months. We performed a multivariate logistic analysis on the clinicopathological parameters and MRI data to identify risk factors for complications and recurrence. RESULTS: The basic parameters of PS were obtained by MRI analysis. The multivariate analysis revealed a large longitudinal sinus diameter (OR = 1.020, 95%CI = 1.000-1.041) and sacrococcygeal dermal thickness (OR = 1.680, 95%CI = 1.142-2.472) to be independent risk factors for early complications. Meanwhile, a small sacrococcygeal fat thickness (OR = 0.923, 95%CI = 0.864-0.987) and a high BMI (OR = 1.291, 95%CI = 1.067-1.563) are independent risk factors for late complications and recurrence, respectively. CONCLUSION: We used MRI to measure the basic parameters of PS accurately, including size, volume, location and some key points of the surrounding tissues, and identified, besides the selection of surgical approach, some specific basic parameters of PS might be the risk factors for complications and recurrence after flap techniques.