The subjects will be treated with a single dose of SP-SAP. They will receive the study drug SP-SAP via a percutaneous intraspinal catheter, they will be monitored for 4 hours and required to stay in the hospital for 24 hours for precautionary care. Their vital signs will be monitored and recorded immediately following the injection. After the catheter has been removed, the following assessments will be made physical exam including motor and sensory functions, and electrocardiogram. A neurologist will be available for consultation as needed.