Efficacy of the C8 Nerve Root Block During Interscalene Block for Anesthesia of the Posterior Aspect of the Shoulder

Efficacy of the 8th Cervical Nerve Root Block During Interscalene Brachial Plexus Block for Arthroscopic Shoulder Surgery: Prospective Randomized Controlled Study

This study evaluates the effects of selective 8th cervical nerve root block during interscalene brachial plexus block on the relief of pain intensity upon the introduction of a posterior portal during arthroscopic shoulder surgery. The 5th to 7th cervical nerve roots will be blocked in half of participants, while the 5th to 8th cervical nerve roots will be blocked in the other half.

By blocking only the 5th to 7th cervical nerve blocks, conventional interscalene brachial plexus block spares the 8th cervical and 1st thoracic dermatomes which innervate the posterior aspect of the shoulder. To visualize the shoulder joint space during shoulder arthroscopic surgery, the introduction of a posterior portal is essential. However, conventional interscalene brachial plexus block cannot effectively relieve the pain caused by its insertion due to sparing of the 8th cervical and 1st thoracic dermatomes. The addition of the 8th cervical nerve root block to conventional interscalene brachial plexus block decreases pain intensity upon the introduction of a posterior portal.

Inclusion Criteria:

• American Society of Anesthesiologists physical status 1 and 2
• Arthroscopic shoulder surgery under interscalene brachial plexus block

Exclusion Criteria:

• Patient refusal
• Contralateral hemidiaphragmatic paralysis or paresis
• Contralateral vocal cord palsy
• Severe pulmonary restrictive disease
• Coagulopathy
• Allergy to local anesthetics or history of allergic shock
• Difficulty communicating with medical personnel
• Peripheral neuropathy or neurologic sequelae on the operative limb