Case ReportSegmental Spinal Myoclonus After a Cervical Transforaminal Epidural Steroid InjectionBoudier-Revéret, Mathieu MD; Chang, Min Cheol MDAuthor Information From the Department of Physical Medicine and Rehabilitation, Centre hospitalier de l’Université de Montréal, Montreal, Quebec, Canada (MB-R); and Department of Rehabilitation Medicine, College of Medicine, Yeungnam University, Daegu, Republic of Korea (MCC). All correspondence should be addressed to: Min Cheol Chang, MD, Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University 317-1, Daemyungdong, Namku, Taegu 705-717, Republic of Korea. Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.ajpmr.com). American Journal of Physical Medicine & Rehabilitation: November 2020 - Volume 99 - Issue 11 - p e128-e130 doi: 10.1097/PHM.0000000000001414 Buy SDC Metrics Abstract In clinical practice, cervical transforaminal epidural steroid injection is commonly used for alleviating pain. We report a case of segmental spinal myoclonus that developed after cervical transforaminal local anesthetic and steroid injection. A 39-yr-old man presented involuntary movements of the bilateral upper trapezius muscles after cervical transforaminal epidural steroid injection on the right C6 and C7 roots with a 5 mg of dexamethasone injectate mixed with 0.5 ml of 1% lidocaine and 0.5 ml of normal saline at each level. His myoclonus was semirhythmic and continuously persisted at a frequency of approximately 30 episodes per minute. The myoclonus continued even at rest and during sleep. In addition, it was resistive to stimulus, such as touch and voluntary action. Based on the clinical features, the patient was diagnosed as having a segmental spinal myoclonus. Clonazepam 0.25 mg was administered three times daily. The myoclonus gradually improved and resolved completely within 2 wks. Segmental spinal myoclonus is one of rare complications after cervical transforaminal epidural steroid injection. Clinicians should be aware of the likelihood of this potential complication. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.