Restoration of Lumbar Lordosis After Posterior Lumbar Interbody Fusion with 4 Degree Cage in Degenerative Spinal Disease

ABSTRACT

STUDY DESIGN: Retrospective radiological evaluation. OBJECTIVES: This purpose of this study is to determine how much lumbar lordosis and disc heights are restored after posterior lumbar interbody fusion (PLIF) with cage in degenerative spinal disease. SUMMARY OF LITERATURE REVIEW Restoration of lumbar lordosis in lumbar spine surgery is crucial for clinical outcomes, but there are few studies about the relationship between restoration of lumbar lordosis and cage. MATERIAL AND METHOD: Eighty-one patients with degenerative spinal diseases underwent PLIF using metal cage with 4degrees lordotic angle. The mean age was 61 year-old (range 38-83 years). Cases with late complications including nonunion, subsidence of cage and instrument failure were excluded in this study. Lumbar lordosis, segmental lordosis, disc height, and sagittal alignment were analyzed on radiographs. RESULTS: The fused level was one segment in 62 patients and two segments in 19 patients. All patients had the fusion from L3 to the sacrum. Preoperative lumbar lordosis was 34.2degrees, improved to 34.6degrees after surgery, and then changed to 32.2degrees at the final follow-up, demonstrating that the cage with 4degrees lordotic angle was not effective to restore lumbar lordosis. Segmental lordosis at the level of cage decreased at the final follow-up as compared to preoperative value at all segments. Disc height was improved at the final follow-up as compared to preoperative value. CONCLUSION: Disc height was restored after PLIF using cage in the surgery for degenerative lumbar spine. However, lumbar lordosis and segmental lordosis were decreased at the final follow-up as compared to preoperative lordosis.