頚椎変性疾患に対してcageを使用した前方除圧固定術の短，中期成績

抄録

The cage has recently been used as the graft of anterior fusion to treat cervical spondylosis, hernia, and OPLL, whose short and middle term result is not gained sufficiently. We treated 114 cases by using threaded and cylindrical cages filled with hydroxapatite. The purpose of the follow up study in these patients was to investigate the height between upper and lower vertebral body inserted cage, loss of lordosis and clinical assessment for 1-7 years. These patients had mild and moderate cases with 8-14 points of the JOA score. Postoperative JOA score revealed some recovery within one year. Excellent and good assessment on 4 stage self-evaluation occupied 95%. However, vertebral height was reduced an additional 2mm in average in 90% of the cases. In the same time, lordosis (Cobb angle between C2 and C7) also decreased (average-2.7 degree). This assessment was not correlative between one and two level fusion. Furthermore, the relationship between clinical assessment and radiological appearance as subsidence of vertebral height and loss of lodosis was not correlative. Only one case had new symptoms due to focal lordosis after anterior fusion of C5/6. The cause of sinking cage was due to operative method with which the endplate was drilled away until cancelous bone was partially exposed. This method did not result in poor outcome in our study. The sufficient decompressing of the nerve root and the spinal cord was accomplished and adjacent vertebral penetration by the cylindrical cage resulted in significant straining of the hydroxapatite which may have invited early fusion.