A comparison of four stimulation patterns in axillary block

Area of Science:

• Anesthesiology
• Regional Anesthesia
• Neuroscience

Background:

• Single-injection axillary blocks may yield inconsistent upper limb anesthesia due to poor local anesthetic spread.
• The retroarterial region of the neurovascular space is critical for anesthetic coverage.

Purpose of the Study:

• To compare the extent of anesthesia produced by single radial-nerve stimulation versus single median-nerve, double (radial and musculocutaneous), or triple (radial, musculocutaneous, and median) nerve stimulation.
• To evaluate the hypothesis that single radial-nerve stimulation provides anesthesia comparable to other techniques.

Main Methods:

• 120 patients received axillary blocks with 40 mL of 1.5% mepivacaine.
• Random assignment to four stimulation groups: median-nerve, radial-nerve, radial + musculocutaneous nerves, or triple-nerve stimulation.
• Sensory block assessed via pinprick at 5 and 20 minutes.

Main Results:

• Radial-nerve stimulation resulted in more extensive anesthesia than median-nerve stimulation.
• Ulnar nerve block occurred more frequently with radial-nerve stimulation.
• Double-nerve stimulation (radial + musculocutaneous) yielded anesthesia similar to triple-nerve stimulation, except for median nerve coverage.

Conclusions:

• Musculocutaneous and radial nerve stimulation are crucial for axillary brachial plexus block success.
• A triple-nerve stimulation technique remains essential for comprehensive upper limb anesthesia.