Stand Alone Cages Via Lateral Or Oblique Lumbar Approaches Versus Posterior Lumbar Interbody Fusions For Adjacent Segment Disease, A Systematic Review And Meta Analysis

Introduction: Adjacent segment disease (ASD) is a frequent occurrence following lumbar fusions, with reported incidence rates as high as 40%, leading to substantial rates of reintervention and imposing significant costs on healthcare systems. Various surgical approaches have been employed to manage patients with ASD, including the posterior approach, which offers benefits such as direct decompression but also presents challenges such as dealing with surgical scarring and the risk of cerebrospinal fluid leaks. The utilization of standalone cages has emerged as a pivotal surgical strategy in addressing ASD. We aim to compare the clinical and surgical outcomes of patients with ASD who underwent management with standalone cages versus posterior approaches (transforaminal or posterior lumbar interbody fusion, TLIF/PLIF).

Methods: A systematic review was conducted following the PRISMA guidelines. PubMed and Embase databases were searched using terms such as ALIF, LLIF, OLIF, TLIF, PLIF, and ASD. Out of 811 articles screened, 11 studies met the inclusion criteria.

RevMan 5.0 was used to analyze both dichotomous and continuous outcomes. When I2 was below 50%, a fixed-effects model was employed, and in instances of high heterogeneity, a random-effects model was utilized.

Results: Results indicated significantly lower blood loss (-311.66 mL, p< 0.001), shorter operative time (-88.35 minutes, p< 0.001), and reduced length of hospital stay (-3.23 days, p< 0.001) in the standalone cage group. Additionally, the standalone group demonstrated significantly higher disc height change (1.67, p=0.001) and lower complication rates (OR=0.38, p=0.02). At follow-up, the standalone group exhibited a higher subsidence rate (OR=4.45, p=0.02) during follow-up. There were no significant changes in lumbar lordosis, segmental lordosis, or Oswestry Disability Index. Moreover, there were no disparities in reoperation rates or pain outcomes.

Conclusion : Standalone lateral cages represent a viable option for treating patients with ASD, demonstrating comparable rates of patient-reported outcomes with fewer complications than TLIF/PLIF. However, patients should be informed about the elevated risk of subsidence.