Focal myelomalacia and syrinx formation after accidental intramedullary lidocaine injection during lumbar anesthesia: A report of 3 cases

Abstract

Three cases of focal myelomalacia and syrinx formation occurring as complications of lumbar spinal anesthesia are reported. In all three instances complication occurred due to accidental injection of lidocaine into the substance of the spinal cord. The primary complaint in all the three cases was severe sharp and shooting pain in both lower limbs, being more severe in certain dermatomes. Neurological deficits were noticed after the effect of the anesthetic agent had worn off. Sensory and motor deficits were asymmetrical and focal; these improved in 6–12 months time. Pain persisted for 1–3 years and then subsided gradually. Carbamazepine and gabapentin were effective in symptomatic relief of this pain. MRI of the dorsolumbar spine done 4–6 months after the spinal anesthetic procedure showed myelomalacic changes with focal syrinx formation in the conus and epiconus region of the spinal cord. The syrinx extended 1–2 vertebral segments in the vertical plane but was confined to a small area in the axial plane. Attempting to use higher lumbar intervertebral spaces for access to the subarachnoid space or epidural space may lead to inadvertent puncture of the lower dorsal spaces; this makes the procedure of spinal anesthesia at this level prone for spinal cord injury, with subsequent risk of development of myelomalacic syrinx in the conus and epiconus region of the spinal cord.