Introduction: The role of interbodies in lumbar arthrodesis has been insufficiently supported by evidence, impacting clinical decision-making and, occasionally, insurance coverage. This study aims to compare clinical and radiological outcomes between lumbar arthrodesis with an interbody cage vs. bone graft alone in patients with degenerative spine disease.
Methods: A systematic review of the literature was performed to identify studies directly comparing outcomes of lumbar interbody arthrodesis with and without interbody cage use. Outcomes of individual studies were synthesized in meta-analyses using random effects models.
Results: Twenty studies with 1,508 patients (769 with interbody cage, 739 without interbody cage) were included. Interbody cage placement was associated with a significantly greater increase in disc height after surgery (4.0mm vs. 3.4mm, p< 0.01). There was a significantly greater reduction of back pain (VAS) in cases where an interbody cage was used (5.4 vs. 4.7, p=0.03). Fusion rates were 5.6% higher in the cage group (96.3% vs. 90.8%) and reached statistical significance (p=0.03). No statistically significant differences were identified between the two groups regarding all-cause reoperation rates, complication rates, improvement in ODI, or leg pain (VAS).
Conclusion : Our results suggest that implantation of an interbody cage is associated with higher rates of fusion, more effective maintenance of disc height, and greater improvement of back pain. This study underlines the clinical value of interbody cages in lumbar arthrodesis for patients with degenerative spine disease.
How to Improve Patient Care: Currently, the use of interbody cages has been incorporated into daily practice with a broad and enlarging spectrum of indications. Evidence regarding the clinical value of interbody cages has been conflicting. Our meta-analysis suggests that implantation of an interbody cage is associated with higher fusion rates, better disc height maintenance and greater back pain improvement.
