Comparison between single-segment Isobar EVO dynamic stabilization and Isobar TTL dynamic stabilization in the treatment of lumbar degenerative diseases: a single center retrospective study over 4 years

OBJECTIVE: Posterior instrumented fusion is the most widely accepted surgical treatment for spinal stenosis and disc herniation. However, fusion can affect daily activities due to lumbar stiffness. In recent years, dynamic stabilization has been introduced to overcome the drawbacks of fusion, however, it is inconclusive whether dynamic stabilization requires the maintenance of a level of activity that is closer to the physiological state of activity for better clinical efficacy. The purpose of this study was to compare the effectiveness of dynamic stabilization with different levels of activity (Isobar EVO and TTL) in the treatment of spinal stenosis and disc herniation. METHODS: This study retrospectively reviewed 80 consecutive patients with lumbar degenerative diseases who were undergoing surgical treatment between March 2014 and July 2018. 41 patients (EVO group) and 39 patients (TTL group) underwent fenestrated decompression with Isobar EVO stabilization and Isobar TTL stabilization, respectively. Clinical outcomes, radiographic data, and postoperative complications were compared between the two groups. RESULTS: At an average follow-up of 52.23 ± 2.97 months, there were no significant differences in the oswestry disability index (ODI) (P > 0.05). The visual analog scale for back pain (VAS(back)) and visual analog scale for the leg pain (VAS(leg)) of the EVO group were lower compared with the TTL group (P < 0.05). The range of motion (ROM) of operated segments were significantly higher in the EVO group as compared to the TTL group (P < 0.05). The intervertebral space height (ISH) of upper adjacent segments were significantly higher in the EVO group as compared to the TTL group (P < 0.05). The overall complications were less in the EVO group, but the difference was not statistically significant (P > 0.05). CONCLUSION: Both Isobar EVO dynamic stabilization and TTL dynamic stabilization can improve clinical outcomes of patients with spinal stenosis and disc herniation. Isobar EVO has advantages over Isobar TTL in terms of improving low back and leg pain, maintaining mobility of the operated segment, and preventing further degeneration of the upper adjacent segment.