Resident Physician NYU Langone Health New York City, New York, United States
Disclosure(s):
Kimberly Ashayeri, MD: No financial relationships to disclose
Introduction: It has been previously shown that expandable cages for transforaminal lumbar interbody fusion (TLIF) are associated with increased rates of subsidence. However, as lateral lumbar interbody fusion (LLIF) cages offer substantially larger footprints, this may offset the risks.
Methods: A retrospective, comparative study of consecutive adult patients undergoing LLIF with either static or expandable cages from 2013 and 2021. Demographics and surgical details were collected. Outcomes of interest included posterior disc height (PDH) restoration, cage position, subsidence, and fusions status. Follow-up were reported at minimum 6-months and 1-year.
Results: A total of 173 LLIF were included: 143 static vs. 30 expandable. Mean age was 63.4 and 62.4% were male. There were no significant differences in age, gender, BMI, smoking, or osteoporosis. Overall, disc height was significantly improved (4.1 v 7.4; p< 0.001). There were no significant differences in change in PDH (3.3 v 3.7 mm; p=0.169), percentage increase in PDH (121.5% v 89.0%; p=0.105), or anteroposterior position of LLIF (24.0 v 21.7; p=0.454) between groups. Overall incidence of subsidence at 6-months and 1-year was 6.9% and 10.4% respectively. There were no significant differences in subsidence rates at 6 months (7.0% v 6.7%; p=0.949) and 1 year (11.2 v 6.7%, p=0.461). Evidence of fusion was present in 92.7% of cases at 1-year. There was no significant difference in rate of fusion between cohorts (92.2% v 95.6%; p=0.555).
Conclusion : Static and expandable cages offer similar PDH restoration depending on surgical goals. Expandable cages seem to be less prone to subsidence than smaller TLIF cage counterparts and offer similar fusion rates to static cages.
