Precise localization of glial scar boundary in chronic spinal cord injury in dogs

Abstract

Objective To establish a method for precise localization of the boundaries of the glial scars in chronic spinal cord injury for their complete resection to provide the experimental basis for neural stem cell transplantation studies. Methods Chronic spinal cord injury was induced in beagl edogs via partial transections of the thoracic segment of the spinal cord. Three months after the operation, with the posterior-medial midpoint of the inferior edge of the first vertebral plate above the bony window defined as the point-of-origin of a 3-dimensional space, the distances from the superior and inferior margins of the injured spinal segment to the point-of-origin were measured on anteroposterior magneti cresonance images (MRI). B-mode ultrasound was used to detect the signal variations in the spinal cord .Immunohistochemistry was performed on the longitudinal sections of the spinal cord for microscopi cmeasurement of the glial fiber lengths in comparison with the length determined by MRl. Results MRI defined a greater length (14.7±0.94 mm) of glial scars with abnormal signals than the actually injured length (10 mm). Ultrasound detected obvious signal changes in the injured spinal cord with distinct boundaries of the injuries. The glial scar length in the spinal cord defined pathologically (18.6± 1.19 mm) exceeded that defined by anteroposterior MRI scanning. Conclusions Anteroposterior MRI scanning combined with stereotactic localization allows approximate determination of the glial scar boundary in the injured spinal cord, and the discrepancies can be adjusted according to the result of pathological measurements. Ultrasonic inspection helps detect the residue scar tissues aRer surgica lresection to ensure complete glial scar resection. Key words: Spinal cord injury; Giiai scar boundary; Magnetic resonance imaging