Preliminary study of spinal cord elastic modulus evaluated by intraoperative shear wave elastography

English Keywords:Cervical spondylotic myelopathy  Shear wave elastography  Elastic modulus

English Abstract:

  【Abstract】 Objectives: To investigate the clinical value and the feasibility of intraoperative shear wave elastography(SWE) in cervical spondylotic myelopathy by measuring spinal cord elastic modulus. Methods: 17 patients undergoing cervical laminoplasty for cervical spondylotic myelopathy in our hospital were evaluated spinal cord elastic modulus by using SWE. There were 11 males and 6 females, aged 58.18±11.49 years old(range, 37-78), duration of disease was from 2 to 180 months(62.06±52.54). There were 4 cases of C3/4, 4 cases of C4/5, 5 cases of C5/6, 2 cases C3/4, C4/5, 1 case of C4/5, C5/6, 1 case of C5/6, C6/7. Preoperative JOA score was averaged 10.74±2.62(6.5-15), BMI was 26.02±3.15kg/m2(range, 19.33-30.76kg/m2), compressed spinal cord flattening rate was (40.07±9.43)%(range, 24.14%-52.93%). Mean, max, min and standard deviation of normal segment and lesion compression segment spinal cord elastic modulus were measured twice. Paired t-test was used to analyze the difference of elastic modulus between the normal and compressed segment spinal cord. t-test was used to analyze the difference of the normal spinal cord elastic modulus between male and female. Pearson correlation was used to analyze the relationship between age, BMI and the elastic modulus of normal segment spinal cord. Pearson correlation was also used to analyze the relationship between the duration of disease, cord flattening rate, JOA scores and elastic modulus of the compressed segment spinal cord. The retest reliability was tested by using the intra-group correlation coefficient(ICC). Results: The mean, max and min values of the elastic modulus of compressed segment were significantly lower than those of normal spinal cord (P<0.01). There was a positive correlation between BMI and normal segment spinal cord elastic modulus(R2＝0.39，P＝0.005). There was no significant correlation between age and normal segment spinal cord elasticity(P=0.88). There was no significant difference in spinal cord elastic modulus between male and female(P=0.68). There was no significant correlation between the duration of disease(R2＝0.001, P＝0.89), cord flattening rate(R2＝0.004, P=0.80), JOA scores(R2＝0.11, P＝0.19) and elastic modulus of the compressed segment spinal cord. The ICC of the elastic modulus in normal segment spine cord was 0.964(95%CI, 0.902-0.987), and which of compressed segment spine cord was 0.842(95%CI, 0.564-0.943). Conclusions: The spinal cord elastic modulus in patients with cervical spondylotic myelopathy measured by SWE is feasible. The elastic modulus will decrease in lesion spinal cord.