Dilute Epinephrine vs Tourniquet for Visualization in Ankle Arthroscopy: A RCT

Inclusion Criteria: * Able to understand the procedures and methods of the clinical trial * voluntarily provide written informed consent * Aged from 15 to 65 years old , regardless of sex * Diagnosed with a condition requiring ankle surgery * Be scheduled to undergo unilateral ankle arthroscopy Exclusion Criteria: * Patients who decline to participate in the study * Known history of heart disease (e.g., coronary artery disease, cardiac conduction abnormalities), diabetes, or asthma * Poorly controlled hypertension * Age under 15 years or above 65 years old * Intellectual disability * Pregnant or breastfeeding women * Known allergy to sulfites Contraindications to ISBPB (including planned injection site infection, pre-existing neurological deficits, allergy to local anesthetics, severe chronic obstructive pulmonary disease, or contralateral phrenic nerve dysfunction)