Follow-up Comparison Study of Single-level Posterior Dynamic Stabilization in Lumbar Degenerative Disease 'Interspinous U'vs. 'DIAM'

Yoon, Seong Min; Lee, Sang Gu; Kim, Eun Young; Kim, Woo Kyung

Abstract

OBJECTIVES
Although successful fusion rates have approached almost 100%, fusion may increase the biomechanical stresses imposed on the adjacent segments leading to transitional disease. These issues have leg some investigators to explore novel approaches, that is 'posterior dynamic stabilization'. In this study, we compared clinical outcome of two different posterior dynamic stabilization instruments: 'Interspinous U' and 'DIAM' device, respectively.
METHODS
A retrospective review was performed for all the patients with disc degenerative diseases treated with decompression procedure from 2004 to 2007. The plain lateral and flexion-extension views were taken immediately after surgery and at each follow-up. The disc height ratio(DH), total lumbar lordotic angle (TLA) and segmental lordotic angle (SLA) were used to observe the change of initial status. The clinical outcome was measured by Odom's criteria and compared. Also, in lateral view, decrease of bony density around instruments was regarded as bony erosion.
RESULTS
Mean follow-up durations for 'Interspinous U' and 'DIAM' were 39 and 14 months, respectively. Instruments were used for 21 and 16 patients for 'Interspinous U and 'DIAM' groups, respectively. Satisfactory groups were 61% and 74% for 'Interspinous U and 'DIAM' groups. But, there was no statistical difference between two groups in the change of DH, TLA and SLA. In 'Interspinous U' group, two cases showed spinal instability with bony erosion, and five cases showed bony erosion around instruments.
CONCLUSION
'DIAM'group showed higher patient satisfaction and no bony erosion. To ascertain the difference, analysis with larger population and a long-term follow-up period will be needed.