This randomized clinical study aims to compare the effects of two different ultrasound-guided infraclavicular brachial plexus block techniques-costoclavicular and lateral sagittal approaches-in patients undergoing forearm, wrist, or hand surgery.

The primary objective of the study is to evaluate and compare the incidence of hemidiaphragmatic dysfunction associated with these two block techniques. Secondary outcomes include sensory and motor block characteristics, postoperative pain scores, analgesic requirements, and potential block-related complications.

Eligible adult patients scheduled for elective forearm or hand surgery are randomly assigned to receive either a costoclavicular or a lateral sagittal infraclavicular nerve block using bupivacaine under ultrasound guidance. Standard general anesthesia and postoperative analgesia protocols are applied.

The results of this study are expected to provide evidence on the relative safety and efficacy of these two infraclavicular block approaches, particularly regarding diaphragmatic function, and to help guide anesthesiologists in selecting the most appropriate regional anesthesia technique for upper extremity surgery.

Inclusion Criteria:

• Adults aged 18-80 years
• ASA physical status I-III
• Scheduled for forearm, wrist, or hand surgery
• Planned infraclavicular brachial plexus block

Exclusion Criteria:

• Refusal of regional anesthesia
• Known allergy to local anesthetics
• Infection at the block site
• Pre-existing neurological deficit in the operative limb
• Severe pulmonary disease
• Coagulopathy or sepsis
• BMI > 40 kg/m²
• Psychiatric disorders