Umbilical Cord Blood Mononuclear Cell Transplant to Treat Chronic Spinal Cord Injury

Inclusion Criteria: * Subjects with chronic spinal cord injury (\>12 months post-initial spinal cord injury surgery) with stable neurologic findings for at least 6 months * Subjects with current neurological status of ASIA A * The neurological level of the subjects is between C5 and T11 * The injured site of the spinal cord is within three vertebral levels * Subjects must be able to read, understand, and complete the VAS * Subjects who have voluntarily signed and dated an informed consent form prior to any study procedures. Exclusion Criteria: * Significant renal, cardiovascular, hepatic and psychiatric diseases * Significant medical diseases or infection * Pregnant or lactating woman * Female of childbearing potential and who is unwilling to use an effective contraceptive method while enrolled in the study * The length of spinal cord lesion exceeds three segments * Unavailability of HLA matched umbilical cord blood cells * any contraindication of laminectomy operation, methylprednisolone and/or lithium carbonate * Subject who is currently participating in another investigational study or has been taking any investigation drug within the last 4 weeks prior to screening of the study * In opinion of the investigator, who suggests that the subject would not be compliant with the study protocol and/or would not be suitable to participate the study