Spinal Cord Stimulator Explant and Revision Complicated by Syrinx Formation: A Case Report and Literature Review.

Spinal cord stimulation (SCS) has been shown to be a safe, effective, and drug-free treatment option for many chronic pain conditions including refractory low back pain. The most commonly reported complication of SCS is equipment failure. We report a case of spinal cord injury (SCI) during SCS explant and revision. This 61-year-old female veteran complained of intermittent shock-like sensations 3-4 times a week for three months prior to her clinic visit. The device was initially implanted in 2009 secondary to neurogenic claudication with appropriate relief. The battery was replaced in 2015. Pain Management Service referred the patient to neurosurgery for replacement of the original SCS unit. Immediately following surgery she complained of severe left lower extremity pain concentrated in the medial thigh radiating into the groin and buttock. She also complained of pain, weakness and numbness in both legs (left more than right). Magnetic resonance imaging (MRI) revealed an edematous area in the left spinal cord between T11-T12. The patient was placed on steroids, ketamine infusion for pain control, and MRI the next day showed slight improvement of the edema and she was discharged home. Follow-up MRI two months later revealed mild diminution in the size of the cord edema. Her pre-operative shock-like sensations had not returned. While rare, spinal cord injury can occur and should be identified and managed expeditiously. Our case here reports for the first time an association between SCS explant/revision and syrinx formation.