Opioid-Sparing Pediatric Anesthesia via Ultrasound-Guided Superficial Cervical Plexus Block with Perineural Dexamethasone in Recurrent Cervical Lymphangioma Excision: An Observational Analytic Case Study. Journal of Anesthesiology and Clinical Research, v. 7, n. 1, p. 161–175, 30 May2026.