Posterior lumbar interbody fusion (PLIF) enables us to perform posterior decompression and anterior reconstruction with single posterior midline approach. We designed trapezoid titanium mesh cage (TPM type N cage) to realign postoperative normal lordotic curve that prevents the progressive degeneration of the disc adjacent to the PLIF-D

Patients: We had 60 PLIFs by using TPM type N cage. There were 41 males and 19 females. The age was 52.6 year-old in average. The patients consisted of 19 degenerative spondylolisthesis, 12 multiply operated back syndromes (MOB), 16 intracanal ossifications, 5 spondylolytic spondylolisthesis, 7 unstable spines, 3 spinal canal stenosis.

Operation methods: Intracanal or extracanal approach was used. The reduction was achieved by restoring the disc heights with rotating disc shaver. The posterior 2/3 endplate were preserved to prevent the cage from sinking into the vertebral body. TPM type N cage with 13mm anterior, 11mm posterior height was used. The trapezoid shape reestablished the lordotic curvature.

Results: Mean follow-up period was 3.3 years (4.4–2.6 years). We evaluated the clinical results with Japanese Orthopedic Association score (JOA score). The preoperative 15.8 JOA score statistically improved to 25.0 in average. There was neither postoperative neurological deterioration nor contamination. Pre-operative 6.4 ± 3.2 mm disc height was statistically improved to 11.5 ± 1.8 mm. Pre-operative 6.4 ± 10.8° lumbar lordotic was statistically improved to 10.5 ± 3.9° The progressive degeneration of the disc adjacent to PLIF was identified in 7case (11%). They had no clinical symptoms.

Conclusion: Trapezoid titanium mesh cage reestablishes lumbar lordotic curvature and prevents progressive degeneration of the disc adjacent to PLIF.