Clinical Outcomes of Lumbar Zygapophyseal Joint Fusion Using Hollow Titanium Facet Fusion Cages – Two Year Results

Purpose: To evaluate the safety profile and fusion rates of hollow titanium lumbar zygophyseal fusion cages compared to traditional posterolateral onlay fusion. Methods: In a prospective case controlled study, Group 1 consisted of 30 adult patients who received one or two level lumbar spinal zygapophyseal joint fusions using paired hollow titanium facet joint implants with adjunctive pedicle screw and rod fixation using a minimal posterior access technique. Group 2 consisted of 30 adult patients undergoing single level lumbar fusion using the same pedicle screw and rod construct but with traditional posterolateral on-lay autograft technique. Perioperative variables including blood loss and inpatient stay were recorded. Independent radiological comparison was completed for each patient using computerized axial tomography (CT scans) were performed at 12 and 24 months post surgery. End outcomes were compared using ANOVA analysis. Results: Blood loss (145 mls vs 350 mls) and inpatient stay (3 days vs 6 days) were significantly lower in Group 1 (p ≤ 0.05). Radiological fusion rates were 100% at 12 and 24 months for Group 1 compared to 89% and 96% respectively for Group 2 (p = 0.20) but this was not statistically significant. There were no signs of facet cage failure or loosening at 2 years. Conclusions: Facet fusion cage insertion is a safe and reproducible technique that results in less patient morbidity through elimination of more extensive paraspinal muscle splitting and through more minimally invasive approaches for the technique.