Interscalene Block Versus Infraspinatus-Teres Minor Interfascial Plane Block for Shoulder Arthroscopy

Comparison of the Effects of Interscalene Block and Infraspinatus-Teres Minor Interfascial Plane Block on Postoperative Analgesia and Diaphragmatic Function in Patients Undergoing Shoulder Arthroscopy.

This prospective randomized controlled study aims to compare the effects of interscalene block, infraspinatus-teres minor interfascial plane block, and a control group on postoperative analgesia and diaphragmatic function in patients undergoing shoulder arthroscopy. A total of 120 patients will be enrolled and allocated into three groups. Postoperative pain scores, opioid consumption, rescue analgesic requirements, and diaphragmatic function will be evaluated and compared among the groups. The study seeks to determine whether the infraspinatus-teres minor interfascial plane block can provide effective postoperative analgesia with less impact on diaphragmatic function compared with interscalene block.

Shoulder arthroscopy is associated with significant postoperative pain. Interscalene block is widely used for analgesia but may impair diaphragmatic function because of phrenic nerve involvement. The infraspinatus-teres minor interfascial plane block has been proposed as an alternative regional anesthesia technique that may provide adequate analgesia while preserving diaphragmatic function. This randomized controlled trial will include 120 adult patients undergoing elective shoulder arthroscopy. Participants will be randomized into three groups: interscalene block, infraspinatus-teres minor interfascial plane block, and control. Pain scores, opioid consumption, time to first rescue analgesia, diaphragmatic excursion measured by ultrasound, and block-related complications will be recorded and analyzed.

Inclusion Criteria:

• Age between 18 and 65 years
• ASA physical status I-II
• Scheduled for elective shoulder arthroscopy
• No known allergy to study medications
• No psychiatric disorder
• No opioid dependence
• Ability to use patient-controlled analgesia (PCA) and complete VAS assessments
• No contraindication to peripheral nerve blocks
• Written informed consent obtained

Exclusion Criteria:

• Refusal to participate
• Uncontrolled hypertension
• Chronic pain or ongoing analgesic treatment
• Significant cardiac disease (coronary artery disease, arrhythmia, heart failure)
• Diabetes mellitus