Introduction: Radiographic fusion guidelines and cost analyses are currently lacking for anterior lumbar interbody fusion (ALIF) procedures. This study was designed to assess fusion rates and costs in patients receiving ALIF procedures with 3 different configurations.
Methods: A retrospective review of 62 patients was conducted, including collection of demographic information, treatment information, and follow-up CT images. Patients either received a stand-alone ALIF (n=37), an ALIF with anterior plating (n=12), or an ALIF with posterior pedicle screw instrumentation (n=13). Seventy-seven levels were treated: L4-L5 (n=25) and L5-S1 (n=52). Assessment of the CT images (N=118) for fusion status was conducted by three independent readers using previously agreed-upon grading criteria.
Cost data (n=59) included total cost, time-related (surgery, anesthesia and recovery room), supply (implants and surgical supply) and all other costs. Statistical comparisons were made using non-parametric tests and logistic regression. Inter-rater reliability was judged using Fleiss’ kappa.
Results: There was no significant difference between groups with respect to age or gender. Fusion rates after six months were not significantly different between stand-alone (93.8%), added anterior (100%) and posterior (87.0%) instrumentation groups. Logistic regression showed increase in fusion status with postoperative time (p=0.001), while level fused and treatment type had no significant effect. Inter-rater reliability was low with a kappa of 0.2631. Cost data on single-level fusions revealed significant differences in total, supply, and operation cost between treatment groups (p<0.001). Median supply costs increased for anterior and posterior fixation when compared to stand-alone ALIF (+29% and 62%, respectively), as did operation costs (10% and 88%), resulting in total cost increases (+19% and 56%).
Conclusions: Fusion status was not significantly different between treatment options, while cost increased substantially with supplemental anterior or posterior instrumentation. When clinically indicated, stand-alone ALIFs may be preferable to additional anterior or posterior instrumentation.
Patient Care: This research will improve patient care by informing physicians of the fusion outcomes and costs associated with differing ALIF modalities. Additionally, this research contains insights into improving non-invasive post-operative fusion grading that may inform future work on standardizing CT fusion criteria.
Learning Objectives: By the conclusion of the session, participants should be able to:
1) Appreciate and better understand the challenges facing the development of fusion criteria for patients treated with ALIF.
2) Identify the cost ramifications of utilizing additional instrumentation versus a stand-alone ALIF.
3) Apply information regarding the timing of post-operative CT imaging to future patient management.