Spinal Myoclonus Responding to Continuous Intrathecal Morphine Pump

Spinal myoclonus is a sudden, brief, and involuntary movement of segmental or propriospinal muscle groups. Spinal myoclonus has occasionally been reported in patients undergoing opioid therapy, but the pathophysiology of opioid-induced myoclonus has not been elucidated yet. Here, we present two patients with spinal segmental myoclonus secondary to ischemic and radiation myelopathy. Conventional medications did not help treat persistent myoclonus in both legs. Continuous intrathecal morphine infusion was implanted for pain control in one patient, which relieved spinal myoclonus entirely. This experience led to the application of this method with a second patient, leading to the same gratifying result. Spinal myoclonus reemerged as soon as the morphine pumps were off, which confirmed the therapeutic role of opioids. In contrast to the opioid-induced myoclonus, these cases show a benefit of opioids on spinal myoclonus, which could be explained by synaptic reorganization after pathologic insults in the spinal cord.

Recurrent spinal myoclonus after two episodes of spinal anesthesia at a 1-year interval: A case report / 대한마취과학회지

Spinal myoclonus is an unusual, self-limiting, adverse event that may occur during spinal anesthesia. The exact cause and underlying biochemical mechanism of spinal myoclonus remain unclear. A few cases of spinal myoclonus have been reported after administration of intrathecal bupivacaine. We report a case in which spinal myoclonus recurred after two episodes of spinal anesthesia with bupivacaine at a 1-year interval in a 35-year-old woman. The myoclonus was acute and transient. The patient recovered completely, with no neurologic sequelae.

Spinal myoclonus on upper extremities following spinal anesthesia: A case report / 대한마취과학회지

Clonic movement is a rare complication that occurs after neuraxial blockade. We report our experience with an 18-year-old man developing myoclonic movement on his both upper extremities following intrathecal injection of 0.5% hyperbaric bupivacaine for varicocelectomy. One and half hour after spinal anesthesia, he developed bilateral, rhythmic myoclonic movements on upper extremities. Two days after surgery, neck flexion was observed. Symptoms sustained for about one month but frequency and severity of clonic movement had been reduced by anticonvulsants and muscle relaxant therapy. Four weeks later, he recovered without any complication.