Clinical Applications Of Anatomic Porous Titanium Fusion Cage In Treatment Of Degenerative Lumbar Disease

Objective:To study the clinical outcomes of using;anatomic porous titanium cage (VIGOR) in degenerative lumbar disease.Method:From August 2006 to June 2008,25 cases(29 segments) of degenerative lumbar disease treated by posterior lumbar interbody fusion(PLIF) using VIGOR cage were followed up.11 males and 14 females with average age of 58.3 years were included. There were 12 cases of disc herniation,7 of lumbar spinal stenosis,3 of degenerative spondylolisthesis and 3 of isthmic spondylolisthesis.All cases were treated by PLIF with posterolateral bone graft,and pedicle screw systems were supplemented.Single cage was inserted in 21 segments and double cages in 8 segments.The average preoperative and postoperative disc space height,foraminal height,lumbar lordosis,segmental lordosis, lumbar tilt,sacral tilt and the amount of sagittal rotation observed between the extremes of movement(on flexion-extension radiographs) were measured and compared.The JOA score and Oswestry Disability Questionnaire were used to evaluate the clinical outcome.Result:The follow-up period ranged from 6 to 29 months with an average of 14.5 months.The fusion rate is 96.6%.The clinical recovery rate(JOA) was 88.0%and the ODI decreased significantly.There were significant retrieve of disc space height and foraminal height,and the restoring of the amount of sagittal rotation observed between the extremes of movement was achieved.Mean lumbar lordosis and segmental lordosis of the fused segments showed significant changes postoperatively.Segmental lordosis increased from 5.0°to 8.5°at L3/4,from 8.6°to 13.7°at L4/5,and from 16.6°to 20.8°at L5/S1,lumbar lordosis increased from 34.4°to 42.3°.Analysis of changes in lumbar tilt did not show significant difference,and sacral tilt increased after surgery.Cases fused with one or two cages have no significant differences in radiological and clinical outcomes. Conclusion:(1) The restoration of the interbody space height and achievement of optimal sagittal alignment of the lumbar spine are relevant factors influencing the clinical outcomes.(2) Compared with threaded fusion cages,the anatomic porous tatinum fusion cage has its advantages in restoring sagittal alignment and keeping bony endplate intact which can prevent the postoperatively subsidence in instrumented PLIF procedures,at the same time,it can accelerates interbody fusion due to an osteointegration of the vertebral endplates by its porous surface without additional bone grafts.(3)With pedicle screw fixation,there is no significant radiological or clinical differences between groups using one or two cages.The use of one cage can reduce the risk and cost of surgery.