Analysis Of The Influence Of Lumbar Internal Fixation To Nearby Bone And Soft Tissue

Objective To investigate the changes of the adjacent segment,the bone and soft tissue surrounding the lumbar internal fixation and their relation with the patient's sydromes, and try to find out the meaning of remove of the internal fixation. Method Part I 20 patients received the operation of the remove of the lumbar internal fixation.The soft tissue and bone grafts surrounding the internal fixation are transected durring the operation. The spiceman is stained with hematoxylin and eosin, CD68 is labelled with immunohistochemistry method. T-test and fisher's exact test are used to recognize the relation of the clinical syndromes and pathological changes. The Oswestry disability index(ODI) scoring is also used to compare the syndrome before and after the operation. Part II 15 patients undergone the post lumbar intervertebral fusion is reviewed and the follow-up period is 22-34 months. The mobility and translations of flexion and extension views,the height of intervertebal space is measured before and after operation separately and compared with pared-T test; 8 out of the 15 patients underwent the operation of internal fixation remove after the first stage follow-up. The height of intervetebral space in X-ray is measured after 6-9 months after the second operation and is compared with the height before the internal fixation remove with paired-T test. Results Part I the different amount of metal debris can be seen in all the tissue around the internal fixation. The debris can be divided by their diameter and shape: the "rough" debris and the "even" debris. The patients with "rough" debris have statistically higher ODI score than the "even" ones (24.26±9.76 vs 10.56±3.64), and remove of internal fixation will more effectively reduce the pain(p<0.05).The metal debris is visible in the bone graft but shows no influence. The distribution of CD68 positive cell is coordinate with the inflammation cells and the mental debris. After the operation, the ODI score of the patients is statistically decreased (p<0.01).Part II the mobility of cranial segments before and after operation to the fusion is statistically significant while the caudal is not. The difference of the height of intervertebal space before and after the fusion is statistically significant. The height of intervetebra space of the adjacent segment has no significant changes after the remove of instrument. Conclusion The internal fixation can release different amount metal debris, and the "rough" debris can induce the obvious local pain. The remove of the internal fixation can relieve pain and other uncomfortable syndrome. There is radiographic evidence of degeneration changes in the adjacent segment after the instrumented lumbar fusion, but it is not related to the incidence of the adjacent segment disease. After the remove of the internal fixation, the adjacent segment is supposed to step down the trend of degeneration, but long-term follow-up is not available.