Ultrasound Predictors of Persistent Burn Scar Pain After Blast and Drone-Related Injuries: A Prospective Cohort Study

Persistent burn scar pain is common after blast and drone-related injuries and may be driven by scar fibrosis, vascular activity, and peripheral nerve involvement within scar tissue. This prospective cohort study aims to determine whether early ultrasound features of scars and nerves predict persistent clinically significant scar pain at 3 and 6 months. Ultrasound measures include scar thickness, echogenicity, Power Doppler vascularity, dynamic adhesion (gliding) assessment, and ultrasound signs of nerve involvement ("US-nerve positive"). Clinical outcomes include pain intensity (NRS), neuropathic pain screening (DN4), and functional interference.

Participants with burn scars 2-12 weeks after injury will undergo standardized baseline assessment including pain ratings at rest, during movement, and on light touch, DN4 screening, basic scar assessment, and a structured ultrasound examination using a high-frequency linear probe (10-18 MHz). Ultrasound endpoints include scar thickness, echogenicity pattern, Power Doppler vascularity grade, dynamic adhesion score, and nerve involvement defined as presence of ≥2 out of 5 ultrasound criteria (focal nerve thickening, hypoechoic fascicular distortion, nerve traversing scar tissue, reduced gliding, and sonopalpation pain reproduction). Follow-up assessments will be performed at 6 weeks, 3 months, and 6 months. The primary analysis will evaluate the association between baseline ultrasound features and persistent clinically significant scar pain (NRS ≥4 during movement or touch) at 3 or 6 months.