RESUMO
PURPOSE: The purpose of this study is to determine how much lumbar lordosis is restored with an eight degree cage in posterior lumbar interbody fusion (PLIF) for degenerative lumbar spinal disease. MATERIALS AND METHODS: A total of 61 patients who underwent PLIF using a metal cage with an eight degree lordotic angle were evaluated. Cases with complications such as subsidence of the cage or instrument failure were excluded from this study. Lumbar lordosis, segmental lordosis, disc height, and bony union were analyzed on the patients' radiographs. RESULTS: Cages were inserted at L3-4 in 17 patients, L4-5 in 54 patients, and L5-S1 in 20 patients. The number of fused level was 1 segment in 32 patients, 2 segments in 27 patients, and 3 segments in 2 patients. The lumbar lordosis was 33.6degrees before surgery, improved to 37.6degrees after surgery, and then was changed to 37.0degrees at the final follow-up. Segmental lordosis at which the cage was inserted was restored after surgery at L4-5 and L5-S1. Disc height was improved with surgery as well. Satisfactory bony fusion was achieved in 95% of the patients. CONCLUSION: PLIF using an eight degree lordotic cage for degenerative spinal disease resulted in restoration of lumbar lordosis and segmental lordosis, although these angles showed some loss of correction after surgery.