Acute sciatic nerve traction injury in rabbits:MRI and pathology comparative study

Objective To approach the model of acute sciatic nerve traction injury in rabbits simulating injury mechanisms in human peripheral nerve by comparison MRI with pathology.Methods One side of sciatic nerve of all 20 New Zealand rabbits were randomly selected to be tracted by smooth forceps to produce the traction injury.The sciatic nerve of the other side of each rabbit was exposed surgically,but not tracted,and defined as the sham-operated group.MRI examination of bilateral sciatic nerves was performed before surgery and at 3 days after traction injury.The MRI examinations consisted of 3D T2-weighted imaging,T1-weighted imaging,3D T2-weighted imaging with SPIR,mixed multiple echo(T1 calculation)and SE multiple echo(T2 calculation)sequences.After MRI examination the nerves were sampled for pathological examination.And the function of hind limbs of each rabbit was record.Results After sciatic nerve traction injury,the motor and reflex function of injured hind limb were abnormal.On MR imaging,the injured sciatic nerve showing high signal intensity on 3D T2WI and T2WI/SPIR,and myelin disaggregation and axon loss histologically.The T1 and T2 relaxation time of proximal segment,tracted segment and distal segment of sciatic nerve after injury were higher than that before injury.Conclusion The injured nerve is characterized as thickened in size and increased T1 and T2 relaxation time.By correlation of MR imaging with pathology,the acute sciatic nerve traction injury animal mode is successfully produced in rabbits.