Laboratory And Clinical Study Of Cervical Lordosis Reconstruction

Cervical spine trauma or degeneration will lead to the intervertebral height and vertebra height loss, which may cause the cervical curvature change. This is the result of the trauma or degeneration as well as the cause of progressive degeneration. Anterior approach of cervical spine has very good curable results for such cases by surgical decompression of the spinal compressor and cervical lordosis reconstruction through intervertebral distraction. The limitation is that there is still no specified measurement for intervertebral distraction during the operation.Intervertebral distraction, which is the important step in cervical lordosis reconstruction, has been appeared long before, but what makes up the resisting force of distraction? What is the distractive torsion change during the distraction? How much is the proper distracting force for different patients? What is the proper stage to use distraction during the operation? What is the quantitative criterion of judging the end of distraction? There is no related report in the literature.Some foreign authors suggested different criterion of the distracting height based on their respective researches. But all these results were those non-laboratory research based clinical reports. The distracting methods used in these researches were different from what was used in the patient surgery. Although these have instructive significance for clinical surgery, but there was still no criterion for how to determine the end of distraction.In our study we modified the distracting handle of the most widely used Caspar retractor into which torsion displayable. We can use it both in the operation and measure the distractive force through it.After 12 cases modeling anterior approach surgery in cadaver cervical specimen, 12 cases distractive measurement on the biomechanical machine of the cadaver cervical segments and measurement in 41 cases of the patients during the operation, we found that the cause of the distractive resistance while intervertebral distractingwas the tensioning of the different cervical ligaments. The distracting force needed to distract the same height decrease along with the surgical processes while anterior longitudinal ligament, intervertebral disk, posterior longitudinal ligament were successively cut or removed. But distracting force variation pattern didn't change, which was increase smoothly at first and markedly after the intervertebral space having been distracted. It is much more markedly if the curve was made from distracting torsion increment. Such variation pattern of the distracting force disappeared if the yellow ligament was cut off in the cadaver specimen.The distracting force varies in different patients. It was relatively lower in cervical trauma patient group while higher in cervical spondylitis myelopathy patient with osteophyte in posterior edge of the vertebral body. Otherwise it may be over distracted or inadequate distraction. It may be better to use the Caspar retractor after the decompression is finished when it is lowest at that time. But if it was needed to enlarger the surgical fields in narrowed intervertebral space, you may use the distractive retractor without the maximum distraction. This can avoid the long time straining of the ligamentous tissue, the loosening of the vertebral screw, and the correct judgment of the distracting end at last. Distracting may stop when the distracting force increment is between 1.44 and 1.99. This may be the criteria judgment for maximum distracting.The study result was applied in 87 cases anterior cervical approach decompression surgery. After the measurement of the intervertebral height on lateral X ray by Sigma Scan Pro 5 we found that the reconstructed lordosis is satisfy, the average intervertebral height increase is 7.27% after surgery. It is stable after half year post-operatively, and no case of further loss was found. The neurological recovery good and excellent rate was 86.21%.Implants or autograft iliac crest and so on were needed to maintain the reconstructed cervical...