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

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.

The 5th to 8th cervical nerve root block under ultrasound guidance using 25 to 30 ml of 0.75% ropivacaine

The 5th to 7th cervical nerve root block under ultrasound guidance using 25 to 30 ml of 0.75% ropivacaine

C5 to T1 dermatomal blockade graded from 0 to 2 (0 = no cold sensation, 1 = reduced cold sensation, and 2 = normal cold sensation) by applying ice to the shoulder

Motor blockade of the radial, ulnar, median, musculocutaneous, and axillary nerves graded from 0 to 2 (0 = complete block, 1 = partial block, and 2 = no block)

Extent of a reduction in the amplitude of excursion of the diaphragm on the vertical axis of the M-mode wave under M-mode ultrasound evaluation

The extent of a reduction in the ipsilateral pupil size measured by a pupillometer Presence or absence of ptosis

Forced expiratory volume at one second (FEV1) and FEV1/forced vital capacity before and 30 minutes after the end of local anesthetic injection

Presence or absence of vascular puncture, local anesthetic systemic toxicity, pneumothorax, and paresthesia

Numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) at admission to postanesthetic care unit

Numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) at discharge from postanesthetic care unit

Numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) between 6 and 12 hours after surgery

Numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) 24 hours after surgery

Worst numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) during 24 hours after surgery

Time at regression of anesthesia which starts to cause postoperative pain during 24 hours after surgery

Likert scale consisting of "very dissatisfied", "dissatisfied", "unsure", "satisfied", and "very satisfied"

Number of patients whose regional anesthesia is converted into general anesthesia due to incomplete surgical anesthesia provided by the regional anesthesia

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

Kim E, Choi CH, Kim JH. Effects of C8 nerve root block during interscalene brachial plexus block on anesthesia of the posterior shoulder in patients undergoing arthroscopic shoulder surgery: study protocol for a prospective randomized parallel-group controlled trial. Trials. 2019 Aug 28;20(1):533. doi: 10.1186/s13063-019-3624-9.