Posterior Lumbar Interbody Fusion Using New Hydroxyapatite Block: Comparison with Metal and PEEK Cages / 대한척추외과학회지

STUDY DESIGN: This is a retrospective study OBJECTIVES: This study compared the clinical outcomes of posterior lumbar interbody fusion (PLIF) using hydroxyapatite blocks with PLIF using a metal or poly-ether-ether-ketone (PEEK) cage. SUMMARY OF THE LITERATURE REVIEW: There are few reports on the clinical outcomes of PLIF using a hydroxyapatite block for treating lumbar degenerative disease. MATERIALS AND METHODS: The 27 PLIF cases (62 units, HA block) that were followed up for 1-year were compared with 13 cases using a metal cage and 13 cases using a PEEK cage. Pedicle screw fixation was performed for all the cases. If the local bone is deficient, then an additional bone graft with autogeous iliac bone or bone substitute was used. The visual analog scale(VAS) for low back pain and radiating pain, the Oswestry disability index (ODI), the intervertebral height and the halo sign around the cages and pedicle screws were comparatively analyzed. RESULTS: The mean VAS score for low back pain before PLIF and using the HA block, the metal cage and the PEEK cage was 7.5, 8.3 and 6.2, respectively, and this was 3.3, 2.9 and 4.8 after PLIF (P0.05, One-way ANOVA). CONCLUSION: PLIF using a HA block showed improvements, including the back pain, and the ODI was satisfactory and this didn't fall below those ODIs of using metal or PEEK cages. Although a HA block may have higher tendency to break, there was no breakage at the 1-year follow up.

Factors Affecting Segmental Lordotic Angle After Posterior Lumbar Interbody Fusion Using Metal Cage / 대한척추외과학회지

STUDY DESIGN: This is a retrospective study. OBJECTIVES: We tried to find out what kind of factors affect the segmental lordotic angle improvement after performing posterior lumbar interbody (PLIF) fusion using a metal cage. The study was done using radiographic measurements. SUMMARY OF LITERATURE REVIEW: For degenerative spinal disease, PLIF with using a metal cage is an effective way to fuse and restore segmental lordosis of the lumbar spine. MATERIALS AND METHODS: The study included 104 patients (65 males, 39 females). Radiographs of the antero-posterior, lateral, flexion and extension views that were taken during the preoperative period and the follow-up 6 months were evaluated for the L4-5 segmental lordosis angle, cage invagination, cage position and disc height. Then, statistical analysis was performed using the Pearson method to determine which factors affected the segmental lordotic angle correction. RESULTS: The increase of the anterior disc height on the postoperative lateral radiograph (gamma=0.303, p<0.01) and the increase of lordosis on the preoperative extension radiograph (gamma=0.384, p<0.01) showed statistically positive correlation with the increase of the postoperative segmental lordosis angle. When comparing between the 4 degrees and 8 degrees cages, the more angle the cage had, the more segmental angle was restored and this was statistically correlated (P<0.05). However, the amount of segmental lordosis angle correction was not as much as the angle of the cage that was used. Other factors such as cage invagination and cage position didn't show statistical correlation. CONCLUSIONS: Posterior lumbar interbody fusion using a metal cage is useful method for restoring the lumbar segmental lordosis angle only if the disc is flexible enough to be distracted (ED note: distracted is the word you want?) sufficiently intraoperatively or if it allows good segmental lordosis, as seen on the preoperative extension radiograph. Correction of the segmental lordosis angle using a wedged cage with a larger angle was not always satisfactory because it did not restore as much angle as the angle of cage that was used.