To Evaluate The Changes Of Nerve Roots Treated By Percutaneous Endoscopic Lumbar Discectomy With DTI-clinical Study

PART ?Objective: To investigate the fractional anisotropy(FA)and the morphology of lumbosacral nerve in healthy volunteers by diffusion tensor imaging(DTI)and diffusion tensor tractography(DTT).Methods: 62 cases of healthy volunteers were enrolled,using the magnetic resonance(MR),respectively,to their conventional MR and DTI scan.The FA values in L3 ~ S1 nerve roots were quantified and compared,and these lumbosacral nerve roots were visualized with tractgraphy.Results: The mean FA value of the healthy volunteers was 0.188 ± 0.020.And each segment did not have significantly differences(Kruskal-Wallis test,H=3.016,p=0.389>0.05).The lumbosacral never roots were clearly visualized with DTT.Conclusion: The FA value of the lumbosacral nerve can be observed by DTI and DTT can intuitively show the path and morphology.PART ?Objective: To evaluat the microstructural changes in compressed lumbosacral nerve roots by DTI and DTT,before an after the percutaneous endoscopic lumbar discectomy(PELD).Methods: 35 cases(37 segments)of LDH patients were examined at the MRI,respectively,to their conventional MR and DTI scan,The FA values of the compressed nerve roots were measured before and after the PELD.The cut-off value of FA in diagnosis of LDH was analyzed by ROC curve.Fiber bundles were traced by DTT.Results: The preoperative FA value(0.1556±0.02)of the LDH patients was significantly smaller than that of the healthy volunteers(t=9.3,p=0.000).The FA values(0.1969±0.019)after the PELD were statistically significant with the preoperative ones(t=13.818,p=0.000).And postoperative FA values were also different from those of healthy volunteers(t=2.498,p=0.013).According to ROC curve analysis can be drawn that:when the FA value were less than 0.1695,the sensitivity,specificity and the area under curve(AUC)value were 81.7%?78.4% and 0.869.Preoperative nerve roots can be seen cut off or narrowed,and a significant recovery after PLED,postoperative nerve roots were similar to the healthy volunteers' in DTT image.Conclusion: DTI can be used to judge the compression of nerve roots and the recovery after PELD by FA value,and DTT can intuitively show the shape of lumbosacral nerve roots before and after PELD,and the microstructural changes of nerve roots were evaluated.