The Use of Methylene Blue in Pilonidal Sinus Surgery Reduces the Risk of Recurrence: A Systematic Review and Meta-Analysis

<i>Background and Objectives</i>: Pilonidal Sinus Disease shows an increasing incidence. Surgical interventions are often necessary; thus, we wanted to analyze whether the usage of methylene blue (MB) for staining the PSD fistulas for better visualization during surgery shows an effect concerning recurrence rates. <i>Materials and Methods</i>: A thorough data search and cross-study data synthesis of publications in the time period of 1833 to 2023 lead to a total of 7936 studies focusing on PSD. The data sets were scanned for the eligibility criteria, namely treatment information, follow-up, recurrence data, and the use of MB in surgery. The data were sorted into different surgical treatment groups, and the recurrence rates were analyzed using Kaplan-Meier-survival curves. <i>Results</i>: A total of 1192 studies involving 130,677 patients were eligible for analysis. A total of 263 studies were performed with MB (22.1%, <i>n</i> = 25,602 patients) and 929 studies without MB (77.9%, <i>n</i> = 105,075 patients). Overall, there was a highly significant difference in RR between the group of MB-stained patients and those without (<i>p</i> < 0.0001), even if analyzed separately for treatments. Primary open approach, primary midline closure, primary asymmetric closure, and Limberg/Dufourmentel all showed a significantly lower RR when MB was used (<i>p</i> < 0.0001). The use of MB in Bascom/Karydakis-Flap showed a statistically significant disadvantage concerning RR (<i>p</i> < 0.0001), and Other Flaps showed less RR with the use of MB (<i>p</i> = 0.011); both groups showed a notable loss of follow-up data, diminishing the meaning of these <i>p</i> values. <i>Conclusions</i>: This study shows that the use of MB as a staining technique in PSD surgery may be beneficial regarding recurrence rates. Therefore, the routinely use of MB staining in PSD surgery should be considered.