Spinal segmental myoclonus following ultrasound-guided suprascapular nerve block: A case report.

Herein, we reported a case of spinal myoclonus following an ultrasound-guided suprascapular nerve block. A 58-year-old male patient who had a diagnosis of calcific tendinitis inside the right supraspinatus tendon received a right suprascapular nerve block (3 mL of 2% prilocaine mixed with 2 mL of 1% lidocaine) under the guidance of ultrasound. Sudden, painless, and involuntary movements began in the upper extremity 10 min after the intervention. Three months after the injection, the involuntary movements were entirely stopped. Involuntary, painless, and brief muscle jerks may be suggestive of myoclonus after interventions with local anesthetics.