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Object Many experimental studies on spinal cord injuries (SCIs) support behavioral improvement after Schwann cell treatment. This study was conducted to evaluate safety issues 2 years after intramedullary Schwann cell transplantation in 33 consecutively selected patients with SCI. Methods Of 356 patients with SCIs who had completed at least 6 months of a conventional rehabilitation program and who were screened for the study criteria, 33 were enrolled. After giving their informed consent, they volunteered for participation. They underwent sural nerve harvesting and intramedullary injection of a processed Schwann cell solution. Outcome assessments included a general health questionnaire, neurological examination, and functional recordings in terms of American Spinal Injury Association (ASIA) and Functional Independence Measure scoring, which were documented by independent observers. There were 24 patients with thoracic and 9 with cervical injuries. Sixteen patients were categorized in ASIA Grade A, and the 17 remaining participants had ASIA Grade B. Results There were no cases of deep infection, and the follow-up MR imaging studies obtained at 2 years did not reveal any deformity related to the procedure. There was no case of permanent neurological worsening or any infectious or viral complications. No new increment in syrinx size or abnormal tissue and/or tumor formation were observed on contrast-enhanced MR imaging studies performed 2 years after the treatment. Conclusions Preliminary results, especially in terms of safety, seem to be promising, paving the way for future cell therapy trials.

Context: The nervous system is the most important system of the body and damaging this system could be lethal for humans. Restoring the function of a damaged nervous system has always been a challenge due to the complexity of this system and its limited ability of regeneration. Furthermore, several obstacles exist in the repair process of the nervous system.Evidence Acquisitions: In the central nervous system (CNS) limited clearance of myelin and formation of inhibitory glial scars make regeneration difficult. There is no effective clinical treatment for damages in the CNS while current treatments focus on stabilization and prevention of further damage and consequently on rehabilitation and preparation of prosthetics and mechanical aids. In peripheral nervous system (PNS) damages, the management may be a nerve autograft or allograft while shortage of donors for nerves makes the situation difficult. Size inequality between the donor nerve and the recipient, danger of neuroma formation and occurrence of infectious diseases are other problems associated with PNS, while indeed complete recovery of function is still not common.Results: Several studies have illustrated that implying tissue engineering strategies for neural repair may lead to considerable improvements in damaged nervous tissues. The development of a scaffold that is similar to the natural extracellular matrix can provide an ideal environment for three dimensional cell cultures, which is a reason for neural tissue engineering success. The need to develop biocompatible and biodegradable material that supports neural tissue growth still exists.Conclusions: This article reviews different types of polymeric materials used in neural tissue engineering and mainly focuses on their properties and their advantages and disadvantages in neural regeneration