To explore the clinical efficacy of endoscopic injection of autologous platelet-rich plasma （PRP） in the treatment of chronic sinus tract，analyze the factors affecting sinus tract healing.

A retrospective analysis was performed on the clinical data of 93 patients with chronic sinus tract admitted to the Department of Burns，Plastic Surgery and Wound Repair，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine，from June 2023 to June 2025，including 42 males and 51 females，with a mean age of （42.2±16.1） years. All patients were divided into the PRP group （43 cases） and the control group （50 cases） according to treatment regimens. Patients in both groups underwent endoscopic sinus tract exploration and debridement. In the PRP group，1-10 mL of PRP was injected into the sinus tract base and wall after debridement based on the size and depth of the sinus tract. The sinus tract healing rate，length of stay and treatment duration were compared between the two groups，and subgroup stratified analysis was conducted according to sinus tract types. Univariate and multivariate Logistic regression analyses were used to identify the influencing factors on sinus tract healing，and the interaction effect between PRP treatment and sinus tract type was tested. Modified Poisson regression was applied for sensitivity analysis. The Enter method was adopted to construct the regression model. The calibration degree and discrimination degree of the model were evaluated by the Hosmer-Lemeshow test and the area under the receiver operating characteristic curve （AUC），respectively.

The sinus tract healing rate of the PRP group was higher than that of the control group （90.7% vs. 58.0%，χ²=12.58，P<0.001）. Subgroup analysis showed that patients with refractory sinus tract derived a relatively greater benifit from PRP treatment （78.6% vs. 5.3%，χ²=18.72，P<0.001）. Univariate analysis indicated that PRP treatment，maximum sinus tract depth，disease course，bacterial detection，sinus tract type and anatomical site were correlated with sinus tract healing （P values all<0.05）. Multivariate Logistic regression analysis revealed that PRP treatment was an independent protective factor for sinus tract healing （OR=15.32，95%CI： 2.91-80.68，P=0.001）. Increased maximum sinus tract depth （OR=0.65，95%CI： 0.49-0.86，P=0.002） and prolonged disease course （OR=0.90，95%CI： 0.82-0.98，P=0.012） were independent risk factors for sinus tract healing. No significant interaction was observed between PRP treatment and sinus tract type （P=0.838）. The AUC of the model was 0.882 （95%CI： 0.795-0.969），and the Hosmer-Lemeshow test verified good calibration of the model （P=0.098）. Modified Poisson regression confirmed the robustness of the conclusions.

Endoscopic PRP treatment can improve the healing rate of chronic sinus tract and serves as an independent protective factor for sinus tract healing. Increased sinus tract depth and prolonged disease course are independent risk factors for sinus tract healing. PRP exhibits a relatively greater efficacy in the treatment of refractory sinus tract，which is recommended as a priority therapy for this subtype.