Motor recovery following olfactory ensheathing cell transplantation in rats with spinal cord injury.

BACKGROUND: Olfactory ensheathing cells (OEC) are considered to be the most suitable cells for transplantation therapy in the central nervous system (CNS) because of their unique ability to help axonal regrowth and remyelination in the CNS. However, there are conflicting reports about the success rates with OEC. AIM: This study was undertaken to evaluate the therapeutic effect of OEC in rat models using different cell dosages. MATERIAL AND METHODS: OECs harvested from the olfactory mucosa of adult white Albino rats were cultured. Spinal cord injury (SCI) was inflicted at the lower thoracic segment in a control and test group of rats. Two weeks later, OECs were delivered in and around the injured spinal cord segment of the test group of the rats. The outcome in terms of locomotor recovery of limb muscles was assessed on a standard rating scale and by recording the motor-evoked potentials from the muscles during transcranial electrical stimulation. Finally, the animals were sacrificed to assess the structural repair by light microscopy. STATISTICAL ANALYSIS: Wilcoxon signed rank test and Mann-Whitney U-test were used to compare the data in the control and the test group of animals. A P value of <0.05 was considered significant. RESULTS: The study showed a moderate but significant recovery of the injured rats after OEC transplantation (P=0.005). CONCLUSION: Transplantation of OECs along with olfactory nerve fibroblasts improved the motor recovery in rat models with SCI.

Biomechanical comparison of short-segment posterior fixation including the fractured level and circumferential fixation for unstable burst fractures of the lumbar spine in a calf spine model.

OBJECTIVE There has been a transition from long- to short-segment instrumentation for unstable burst fractures to preserve motion segments. Circumferential fixation allows a stable short-segment construct, but the associated morbidity and complications are high. Posterior short-segment fixation spanning one level above and below the fractured vertebra has led to clinical failures. Augmentation of this method by including the fractured level in the posterior instrumentation has given promising clinical results. The purpose of this study is to compare the biomechanical stability of short-segment posterior fixation including the fractured level (SSPI) to circumferential fixation in thoracolumbar burst fractures. METHODS An unstable burst fracture was created in 10 fresh-frozen bovine thoracolumbar spine specimens, which were grouped into a Group A and a Group B. Group A specimens were instrumented with SSPI and Group B with circumferential fixation. Biomechanical characteristics including range of motion (ROM) and load-displacement curves were recorded for the intact and instrumented specimens using Universal Testing Device and stereophotogrammetry. RESULTS In Group A, ROM in flexion, extension, lateral flexion, and axial rotation was reduced by 46.9%, 52%, 49.3%, and 45.5%, respectively, compared with 58.1%, 46.5%, 66.6%, and 32.6% in Group B. Stiffness of the construct was increased by 77.8%, 59.8%, 67.8%, and 258.9% in flexion, extension, lateral flexion, and axial rotation, respectively, in Group A compared with 80.6%, 56.1%, 82.6%, and 121.2% in Group B; no statistical difference between the two groups was observed. CONCLUSIONS SSPI has comparable stiffness to that of circumferential fixation.