Comparison of the Effectiveness of USG-Guided Interscalene Block Versus Combined Interscalen-Suprascapular Block for Arthroscopic Shoulder Surgery

Comparison of the Effectiveness of Ultrasound-Guided Interscalene Block Versus Combined Interscalene and Suprascapular Nerve Blocks in Arthroscopic Shoulder Surgery

This study aims to compare two commonly used regional anesthesia techniques for shoulder arthroscopy: the ultrasound-guided interscalene block and the combined interscalene-suprascapular nerve block. Both techniques are routinely performed to reduce pain during and after shoulder surgery. The purpose of this study is to determine which method provides better postoperative pain control, reduces the need for pain medication, and causes fewer side effects such as diaphragmatic dysfunction. Participants will receive one of the two nerve block techniques before surgery, and their pain scores, opioid consumption, and respiratory effects will be monitored during the first 24 hours after the operation.

Arthroscopic shoulder surgery is a commonly performed procedure, and effective perioperative analgesia is essential for improving patient comfort, reducing opioid consumption, and enabling early rehabilitation. The ultrasound-guided interscalene block is considered the standard regional anesthesia technique for shoulder surgery; however, it may cause hemidiaphragmatic paresis due to phrenic nerve involvement. To reduce this risk while maintaining effective analgesia, the combination of interscalene and suprascapular nerve blocks has recently gained attention as a promising alternative.

The suprascapular nerve supplies approximately 70% of sensory innervation to the shoulder joint, and its blockade may enhance postoperative pain control when combined with a low-volume interscalene block. This combined technique has been proposed as a potentially safer option with fewer respiratory side effects, particularly in patients at risk of reduced pulmonary reserve.

This prospective, randomized clinical study aims to compare the analgesic efficacy and respiratory effects of the ultrasound-guided interscalene block versus the combined interscalene-suprascapular nerve block in patients undergoing arthroscopic shoulder surgery. Participants will be assigned to one of the two block techniques prior to surgery. Standardized anesthesia and postoperative care protocols will be applied. Primary outcomes include postoperative pain scores and opioid consumption during the first 24 hours. Secondary outcomes include diaphragm excursion measurements, block-related complications, patient satisfaction, and recovery profiles.

The results of this study are expected to contribute to determining whether the combined technique provides comparable or superior analgesia with fewer respiratory side effects, potentially offering a safer alternative to traditional interscalene block for shoulder surgery.

Inclusion Criteria:

Planned arthroscopic shoulder surgery ASA physical status I-III Age between 18 and 75 years Ability to provide informed consent Suitable for regional anesthesia with ultrasound guidance

Exclusion Criteria:

Allergy or contraindication to local anesthetics Coagulopathy or current anticoagulant therapy Infection at the block injection site Severe pulmonary disease (e.g., severe COPD) Pre-existing neurological deficit in the operative upper limb Body mass index > 40 kg/m² Pregnancy or breastfeeding History of phrenic nerve palsy Inability to cooperate with block procedure or follow-up