Ultrasound-Guided Root/Trunk (Interscalene) Block for Hand and Forearm Anesthesia

Abstract

Background Historically, the anterolateral interscalene block—deposition of local anesthetic adjacent to the brachial plexus roots/trunks—has been used for surgical procedures involving the shoulder. The resulting block frequently failed to provide surgical anesthesia of the hand and forearm, even though the brachial plexus at this level included all of the axons of the upper extremity terminal nerves. However, it remains unknown whether deposition of local anesthetic adjacent to the seventh cervical root or inferior trunk results in anesthesia of the hand and forearm. Methods Using ultrasound guidance and a needle-in-plane posterior approach, a Tuohy needle was positioned with the tip located between the deepest and next-deepest visualized brachial plexus root/trunk, followed by injection of mepivacaine (1.5%). Grip strength and the tolerance to cutaneous electrical current in 5 terminal nerve distributions were measured at baseline and then every 5 minutes following injection for a total of 30 minutes. The primary end point was the proportion of cases in which the interscalene nerve block resulted in a decrease in grip strength of at least 90%, and hand and forearm anesthesia (tolerance to >50 mA of current in all 5 terminal nerve distributions) within 30 minutes. The primary hypothesis was that a single-injection interscalene brachial plexus block produces a similar rate of anesthesia of the hand and forearm to the published success rate of 95% for other brachial plexus block approaches. Results Of 55 subjects with blocks placed per protocol, all had a successful block of the shoulder as defined by inability to abduct at the shoulder joint. Thirty-three subjects had measurements at 30 minutes following local anesthetic deposition, and only 5 (15%) of these subjects had a surgical block of the hand and forearm (P < 0.0001; 95% confidence interval [CI]: 6–33%). We therefore reject the hypothesis that the interscalene block as performed in this study provides equivalent anesthesia to the hand and forearm compared with other brachial plexus block techniques. Block failures of the hand and forearm were due to inadequate cutaneous anesthesia of the ulnar (n = 27; 82%), median (n = 26; 78%), or radial (n = 22; 67%) distributions; the medial forearm (n = 25; 76%), and/or the lateral forearm (n = 14; 42%). Failure to achieve at least a 90% reduction in grip strength occurred in 16 subjects (48%). Conclusions This study did not find evidence to support the hypothesis that local anesthetic injected adjacent to the deepest brachial plexus roots/trunks reliably results in surgical anesthesia of the hand and forearm.

A Comparison of Combined Suprascapular and Axillary Nerve Blocks to Interscalene Nerve Block for Analgesia in Arthroscopic Shoulder Surgery

“…17 In the present study, we observed incomplete sensory block in the median (43%), musculocutaneous (20%), radial (33%), and ulnar (78%) territories. Although this may appear surprising, Madison et al, 18 using an ISB insertion technique targeting the C7 root for anesthesia of the hand, found inadequate sensory block of the musculocutaneous nerve in 42% at 30 minutes using mepivacaine 1.5%.…”

Comparison of Ultrasound-Guided Supraclavicular, Infraclavicular and Below-C6 Interscalene Brachial Plexus Block for Upper Limb Surgery: A Randomised, Observer-Blinded Study

“…Our success rate in supraclavicular and infraclavicular groups was comparable to previous reports using US-guided nerve blocks 3,4,7 . Though the interscalene block has been found to be highly effective for shoulder surgery 11,12 , a high incidence of inadequate anaesthesia of the forearm and hand has been reported 20 . The high surgical effectiveness of interscalene blockade for arm and forearm surgery in our study may be due to the use of a different approach or choice of local anaesthetic type and volume.…”

Ultrasound-guided percutaneous peripheral nerve stimulation: neuromodulation of the suprascapular nerve and brachial plexus for postoperative analgesia following ambulatory rotator cuff repair. A proof-of-concept study

“…Beginning 30 min following Stimulator C initiation, subjects could receive intravenous fentanyl or hydromorphone prior to discharge and/or receive a single-injection interscalene nerve block (ropivacaine 0.5%, 20 mL, with epinephrine) 13. Subjects and their caretakers were provided verbal and written instructions on stimulator/lead care and management.…”