ABSTRACT
Objective To assess the clinical effect of oblique lumbar interbody fusion (OLIF) combined with percutaneous pedicle screw fixation on computer navigation for lumbar spondylolisthesis.Methods Total 20 patients (8 males and 12 females with average age of 54.1± 12.3 years) with lumbar spondylolisthesis were enrolled in our study during Oct.2014 and May.2016.All patients were treated with OLIF combined with percutaneous pedicle screw fixation on computer navigation.Operation time,blood loss and complications were all recorded.Clinical and Radiographic evaluation were investigated on 1 week,3 months,6 months,12 months postoperatively and final follow-up.Visual analogue scale (VAS) for low back pain and leg pain,Oswestry disability index (ODI) for low back pain and the MOS item short form health survey (SF-36) were used to evaluate the clinical efficacy of surgery.Disc height,disc angle,lumbar lordosis and degree of upper vertebral slip of patients were investigated with X-ray.Cross-sectional area of intervertebral foramina was measured with three-dimensional CT and MRI.The cross-sectional area and sagittal diameter of the thecal sac were measured on T2-weighted axial and sagittal magnetic resonance images.Accuracy of pedicle screw placement was investigated with three-dimensional CT.Fusion rate was investigated with three-dimensional CT and Xray.Results All patients were followed for 12-30 months (22.9±4.8 months).The mean operation time was (119.0±23.8) min,the mean blood loss was (57.8±20.6) ml.VAS for low back pain,VAS for leg pain,and ODI were significantly improved from (6.7± 2.6),(6.3±2.7) and 50.5％±18.2％ preoperatively to (1.3±1.0),(0.8±1.0) and 14.0％±9.6％ at the latest follow-up.The SF-36 PCS and MCS scores were improved from (27.1 ± 13.9) and (51.0±22.7) preoperatively to (67.3± 18.9) and (81.2±14.1) at the latest follow-up.Disc height,disc angle,lumbar lordosis were significantly increased from (6.0±3.6) mm,1.8°±6.2° and 39.2°±8.4° preoperatively to (10.8± 1.7) mm,6.2°±3.5° and 45.0°±7.8° at the latest follow-up.Degree of upper vertebral slip of patients was reduced from 23.5％±7.4％ preoperatively to 4.2％±3.1％ at the latest follow-up.Cross-sectional area of intervertebral foramina in CT and MRI were significantly increased from (140.6±36.0) mm2 and (78.1±31.2) mm2 before surgery to (179.8±35.6) mm2 and (141.7±29.5) mm2 at 6 months after surgery.Cross-sectional area and sagittal diameter of thecal sac were significantly increased from (73.4±29.3) mm2 and (5.2±3.2) mm before surgery to (124.5±26.6) mm2 and (9.5±2.0) mm at 6 months after surgery.Accuracy of pedicle screw placement was 95％,and fusion rate was 100％ at 6 months after surgery.There were no severe vascular and nerve injuries.Conclusion OLIF combined with percutaneous pedicle screw fixation on computer navigation has good indirect decompression effect on lumbar spondylolisthesis,and was associated with high fusion rate.It can also effectively decrease the surgical trauma,improve the accuracy of pedicle screw placement,and increase disc height,disc angle and lumbar lordosis.