RESUMEN
INTRODUCTION: The transforaminal lumbar interbody fusion (TLIF) is among the most utilized methods for the surgical treatment of lumbar degenerative disc disease. The TLIF has advanced significantly with several iterative changes since its inception in the early 1980s, with the advent of several generations of interbody types, shapes, and materials. Steerable curvilinear interbodies are among the most recent innovations in this space and may offer biomechanical advantages, namely in preservation of lumbar and segmental lordosis. While radiographic parameters have been investigated for other cage shapes and lumbar interbody fusion techniques, no study has investigated postoperative radiographic outcomes specific to TLIFs done with curvilinear interbodies. METHODS: This study is a retrospective review of TLIFs performed with curvilinear interbodies between 2019 and 2022 at a single institution. Upright radiographs were obtained preoperatively and at several timepoints postoperatively. Radiographic variables including interspace height and segmental lordosis were collected. RESULTS: 26 surgeries with 32 curvilinear interbodies were performed across 3 years. There was significant increase in segmental lordosis at the L4-L5 (p = 0.0183) and L5-S1 levels (p = 0.004) as well as interspace height postoperatively at levels L3-L4 (p = 0.011) and L4-L5 (p = 0.002). Pain as measured with the numeric rating scale significantly improved in the overall cohort postoperatively (p<0.001). CONCLUSIONS: TLIF with curvilinear interbody placement increases segmental lordosis and interspace height at the L4-L5 and L5-S1 levels, and increased interspace height at the L3-L4 and L4-L5 levels. Further investigation into additional radiographic parameters is warranted and expanded cohort size would benefit deeper analysis of other spinal levels. IMPLICATIONS FOR PRACTICE: As an increasing number of cage designs and materials are brought to market, studies such as this allow for better understanding of cage specific outcomes allowing for better informed device selection.
