A novel, minimally invasive technique to establish the animal model of spinal cord injury

BACKGROUND: Spinal cord injury (SCI) is a traumatic disease that is associated with high morbidity, disability, and mortality worldwide. The animal spinal cord contusion model is similar to clinical SCI; therefore, this model is often used to study the pathophysiological changes and treatment strategies for humans after SCI. The present study aimed to introduce a novel, minimally invasive technique to establish an SCI model, and to evaluate its advantages compared with conventional methods. METHODS: Incision length, blood loss, length of time, and model success rate during the operation were recorded. Postoperative hematuria, incision hematoma, scoliosis [detected by micro computed tomography (Micro-CT)] and mortality were analyzed to evaluate surgical complications. The visual observation of the tissue was used to compare the effect of laminectomy by 2 methods on the scar hyperplasia at the injured site. Basso-Beattie-Bresnahan (BBB) score and catwalk automated quantitative gait analysis were conducted to measure behavioral function recovery. To evaluate the nerve function recovery of rats postoperatively, somatosensory evoked potential (SEP) and motor evoked potential (MEP) were studied by electrophysiological analyses. RESULTS: The results of operation-related parameters of the two models (conventional surgery group vs. minimally invasive surgery group) were as follows: surgical incision length: 23.58±1.58 versus 12.67±1.50 mm (P<0.05), blood loss: 3.96±1.05 versus 1.34±0.87 mL (P<0.05), and total operative time: 12.67±1.78 versus 10.33±1.92 min (P<0.05). In addition, the success rate of the 2 models was 100%. Surgical complications (conventional surgery group vs. minimally invasive surgery group) were as follows: hematuria: 25% versus 8.3%, kyphosis: 25% versus 0%, incision hematoma: 30% versus 9%, and mortality: 25% versus 8.3%. Micro-CT indicated severe scoliosis in the conventional surgery group. Gross tissue results showed that the conventional surgery group had more severe fibrous scar hyperplasia. The results of the BBB scores, catwalk automated quantitative gait analysis, and electrophysiology showed that the difference between the two groups was statistically significant in terms of behavioral recovery and neuroelectrophysiology. CONCLUSIONS: The minimally invasive technique has the advantages of small incision and reduced tissue damage and surgical complications, and may be used as an alternative spinal cord contusion method.