抄録
Recently, instrumentation has become more and more rigid. But rigidity has it’s limits, which is why the author has treated patients more than 70 years old with spondylolisthesis or degenerative lumbar scoliosis using flexible transpedicular instrumentation. The authors presented a series of 25 cases with the Twinflex flexible spinal instrumentation for lumbar fusion. The mean follow-up period was 19.6 months range from 6 months to 55 months.
The 25 cases included 13 cases of spondylolisthesis, 7 cases of degenerative lumbar scoliosis, and 5 cases with both lumbar diseases. The degenerative lumbar scoliosis group tended to have longer fusion.
The mean Japan Orthopaedic Association (JOA) lumbar score for the 25 cases improved from 12.8 points before operation to 24.7 points at a mean follow-up of 19.6 months. However, the mean improvement in JOA score for the lumbar degenerative scoliosis group was lower. Although the authors did not specifically attempt reduction, the percentage of slip and tilt angles were improved at the first post-operative week. Finally, the spondylolisthesis group had no correction loss, but the degenerative lumbar scoliosis group had correction loss. In one case, a clear zone around the transpedicular screws appeared on radiographs, and in two cases transpedicular screw cut out occurred. None of the cases had screw fracture or rod failure. Infection was not a complication in any case.
At the last follow-up examination, there were no significant differences in lordosis between anteflexion and retroflexion on radiographs.
We concluded that Twinflex flexible spinal instrumentation was a useful device for spinal fusion in patients more than 70 years old.
