Abstract
Introduction
StaXx XD is an expandable PEEK wafer implant that has been used in the treatment of lumbar degenerative disease. PEEK implants have been successfully used as interbody devices. There have been little studies evaluating the outcome of expandable PEEK devices. The aim of the current study was to determine the clinical effectiveness and radiographic outcome of expandable PEEK cages for interbody fusion.
Materials and Methods
This was a retrospective study of 49 consecutive patients who underwent lumbar interbody fusion with implantation of expandable PEEK cages in combination with posterior instrumentation using pedicle screw-rod constructs primarily for degenerative disorders. The patient's clinical outcomes were evaluated using the visual analog scale (VAS) and the Oswestry disability index (ODI). In addition, disc height, foraminal height, listhesis, local disc angle, lumbar lordosis, and graft subsidence were evaluated on pre-op, post-op, and on latest follow-op imaging.
Results
A total of 16 patients (32.6%) had undergone previous surgery at the index level. From pre-op to an average follow-up of 19.3 months, there was significant improvement in VAS back (6.42 vs. 3.11, p < 0.001), VAS buttock (4.66 vs. 1.97, p = 0.002), VAS leg (4.55 vs. 1.96, p < 0.001), and ODI (21.7 vs. 12.1, p < 0.001) scores. In addition, there was significant increase in the average disc height (6.49 vs. 8.18 mm, p = 0.037) and foraminal height (15.6 vs. 18.53, p = 0.0001), and there was a significant reduction in the amount of listhesis (5.13 vs. 3.15, p = 0.005). The increase in average local disc angle and overall lumbar lordosis was not significant. Subsidence of 0.66 mm (7.4%) was observed at the latest follow-up (p = 0.35).
Conclusion
Our mid-term results indicate that in situ expandable PEEK spacers for lumbar interbody distraction can effectively and durably restore the disc height and foraminal height and are associated with significant improvement in the clinical outcome.
None declared