Interscalene Block Versus Combined Infraclavicular-Anterior Suprascapular Blocks for Shoulder Surgery

A Randomized Comparison Between Interscalene And Combined Infraclavicular-Anterior Suprascapular Nerve Blocks For Arthroscopic Shoulder Surgery

Postoperative analgesia after shoulder surgery remains a challenge in patients with preexisting pulmonary pathology, as interscalene brachial plexus block (ISB), the standard nerve block for shoulder surgery, carries a prohibitive risk of hemidiaphragmatic paralysis (HDP). Although several diaphragm-sparing nerve blocks have been proposed, none seems to offer equivalent analgesia to ISB while avoiding HDP altogether. For instance, even costoclavicular blocks, which initially fulfilled both requirements, were subsequently found to result in a non-negligible 5%-incidence of HDP.

In this randomized trial, the authors set out to compare ISB and combined infraclavicular block-anterior suprascapular nerve blocks (ICB-ASSNB) for patients undergoing arthroscopic shoulder surgery. The authors hypothesized that ICB-ASSNB would provide equivalent postoperative analgesia to ISB 30 minutes after shoulder surgery and therefore designed the current study as an equivalence trial.

Inclusion Criteria:

• Patients undergoing arthroscopic shoulder surgery
• American Society of Anesthesiologists classification 1-3
• Body mass index between 20 and 35 kg/mt2

Exclusion Criteria:

• Adults who are unable to give their own consent
• Pre-existing neuropathy (assessed by history and physical examination)
• Coagulopathy (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. platelets ≤ 100, International Normalized Ratio ≥ 1.4 or prothrombin time ≥ 50)
• Obstructive or restrictive pulmonary disease (assessed by history and physical examination)
• Renal failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. creatinine ≥ 100)
• Hepatic failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. transaminases ≥ 100)
• Allergy to local anesthetics (LAs)
• Pregnancy
• Prior surgery in the neck or infraclavicular region
• Chronic pain syndromes requiring opioid intake at home