Application Of RF-Ⅱ Pediclescrew System And Cage In Lumbar Spondylolisthesis

Objective To study and evaluate the practical value and efficacy of application of RF-II pedicle screw system and Cage in lumbar spondylolisthesis, and also to study its surgical techniques.Methods Treatment group:fifty-six of patients undergone posterior lumbar spinal decompression and interbody fusion surgery with RF-II pedicle screw system and Cage from August, 1998 to June,2002 were reviewed retrospectively. There were 29 males and 27 females with an average age 41.2 years old. Control group: Forty-five of patients undergone reduction with RF-II pedicle screw system and posterolateral fusion from June 1997 to June 2002 were reviewed retrospectively. There were 24 males and 21 females with an average age 44.2 years old . The data of clinical symptoms and signs and radiographic outcomes were obtained before and after surgery and during a followe-up period.Results Treatment group: the mean follow-up time was 29.1 months (range: 6~52months). Fifty-two of cases with incompletely neurological defect got improved postoperatively; the rate of satisfaction is 92.9% ; solid fusions of bone were observed in 52 cases and no compilations such as the loosening and dislocation and breakage of screw, but screws werenot implanted properly in 2 cases. Control group: the mean follow-up time was 37.2 months (range:6~66months). Thirty-three of cases with incompletely neurological defect got improved postoperatively; the rate of satisfaction is 73.3% ; nonunion was observed in 11 cases.Conclusion RF-II pedicle screw system is an ideal internal fixator for the reduction of the spondylolisthesis and the stabilization of the fixation segments. It also promotes bone graft fusion and privides conditions to improve the spinal cord function. Accurate orientation, enough decompression, proper implantation of internal fixator and bone graft is the key of a successful surgery. Cage is an ideal internal implant for interbody fusion. It can promote interbody fusion and avoid iliac graft bone and keep the height of intervertibral space and the stability of the fixation segment ;it has high graft bone fusion and also decrease the injury from iliac graft.