Motor response evaluation during brachial plexus block anesthesia: An ultrasonography aided study

Area of Science:

• Anesthesiology
• Neuroscience
• Anatomy

Background:

• Ulnar nerve sparing can cause upper limb blockade failure.
• Local anesthetic injection for finger flexion has a high success rate.
• Lower trunk stimulation is crucial for median and ulnar nerves.

Purpose of the Study:

• To evaluate alternative motor responses for successful lower trunk brachial plexus blockade.
• To determine if wrist flexion, forearm pronation, or other twitches can indicate successful lower trunk blockade.

Main Methods:

• Patients underwent ultrasound-assisted or open brachial plexus stimulation.
• Motor responses to lower trunk stimulation were documented.
• Evaluated responses included finger flexion, wrist flexion, and forearm pronation.

Main Results:

• Wrist flexion observed in 52% of subjects.
• Finger flexion observed in 61% of subjects.
• Forearm pronation or anterior compartment twitches observed in 48% of subjects.

Conclusions:

• Wrist flexion, forearm twitches, and pronation are viable indicators for lower trunk blockade.
• These responses, along with finger flexion, can enhance blockade accuracy.
• Alternative motor responses improve the reliability of upper limb blockade.