Optimizing Percutaneous Sclerotherapy in Venous Malformations: A Longitudinal Analysis of Pain Relief and Treatment Plateau Effect.

OBJECTIVE: To characterize the longitudinal pain relief pattern across successive pingyangmycin-based percutaneous sclerotherapy (PYM-PS) sessions in patients with venous malformations (VM), and to evaluate whether treatment efficacy exhibits a plateau effect. METHODS: A linear mixed-effects model (LMM) was applied to analyze visual analogue scale (VAS) pain scores across successive PYM-PS sessions. Fixed effects included treatment session, baseline pain VAS score, age, lesion volume, and treatment interval, with patient-specific variability as random effect. Pre- and post-treatment pain VAS scores and ultrasound (US) blood supply levels were compared, and complications were documented. RESULTS: A plateau effect in pain relief was observed after the third treatment session, with further sessions not completely ineffective yet offering limited therapeutic benefits. Fixed effects explained 46% of VAS score variance, rising to 68% when including random effect. Significant predictors of favorable clinical outcomes included increasing number of treatment sessions (p = 0.04), lower baseline pain score (p < 0.001), and younger age (p = 0.03), while lesion volume and treatment interval had no significant impact (p = 0.18 and p = 0.87, respectively). Significant differences in overall pain scores and US blood supply were observed after treatments (p < 0.001), with 83.4% overall treatment efficacy and no major complications. CONCLUSION: PYM-PS effectively and safely relieve pain in VM patients, with a plateau effect emerging after about three treatment sessions. These findings support a standardized protocol of three PYM-PS sessions as a re-evaluation timepoint for optimizing individualized treatment planning.