Treatment of Spinal Myoclonus Due to Degenerative Compression Myelopathy with Cervical Spinal Cord Stimulation: A Report of 2 Cases.

BACKGROUND

Spinal myoclonus (SM) is a rare hyperkinetic movement disorder that is either idiopathic or secondary to spinal cord lesions. The treatment is either symptomatic only or addresses the underlying etiology. We describe 2 patients with SM with compression myelopathy who were treated with spinal cord stimulation (SCS).

CASE DESCRIPTION: The first patient was a 39-year-old man with cervicobrachial pain owing to compression myelopathy at level C5-6 underwent fusion. A year later, he developed neurologic deficits including left-limb dominant tetraparesis and involuntary movements of the right leg. Despite ventral fusion at C5-7 due to progressive myelopathy, the involuntary movements extended to both left extremities. A paddle electrode was placed at level C5-6. SM disappeared immediately under stimulation, and the effect continued even after 24 months. The second patient, a 57-year-old man, underwent fusion at level C5-6 in 1998. Since then, he experienced a persistent tremor in his left hand. After 20 years, he developed cervicobrachial pain of the right upper limb with paresis. Compression myelopathy at segment C6-7 was treated with fusion plating. Six months later, pain returned in both upper limbs, and the tremor extended discretely to his right side. A paddle electrode for SCS was placed at level C7-Th1. SM disappeared immediately under stimulation, and the effect persisted after 10 months. Both patients reported sustained pain reduction.

CONCLUSIONS

SCS might offer a more selective medicament-free therapy option for SM. The activation of intraspinal networks and replacement of supraspinal descending influences are mechanisms of SCS in this disorder.