BACKGROUND CONTEXT Restoration of sagittal balance is critical for deformity correction. Hyperlordotic lateral lumbar interbody fusion (LLIF) spacers are available in many sizes, and possess up to 25° of implant lordosis to maximize lumbar lordosis when used in combination with anterior longitudinal ligament (ALL) resection. However, angular mismatch between the implant and vertebral endplates may play a role in subsidence due to asymmetric loading of the anterior implant edge. The relationship between implant height and lordosis selection, and their effect on segmental lordosis correction and anterior-posterior endplate loading, is poorly understood. PURPOSE Investigators quantified segmental lordosis and anterior-posterior endplate loading achieved over a range of commercially available implant dimensions (heights: 9–21mm, and lordosis: 0–25°). STUDY DESIGN/SETTING In vitro human cadaveric study PATIENT SAMPLE Six cadaveric specimens OUTCOME MEASURES Lordosis and anterior-posterior endplate forces METHODS Six L2–L3 cadaveric segments were used. A 112.5 lb axial load was applied to L2 to simulate forces during upright stance. Segments were instrumented with bilateral pedicle screws and a sequence of LLIFs under fluoroscopy, including: (A) 9mm height with 0°, 6° and 10° lordosis with intact ALL; (B) 9mm height with 0°, 6° and 10° lordosis following ALL resection; (C) 11mm height with 10° and 20° lordosis; (D) 13mm height with 20° lordosis; and (E) 25° lordosis of 13, 15, 17, 19 and 21mm heights. Segmental lordosis and endplate force-maps were collected until anterior expulsion precluded testing completion (n=6, unless otherwise noted). An equivalent loading ratio (ELR=anterior load/total load*100%) was calculated; ELR=80% refers to 80% anterior and 20% posterior edge loading. An ELR between 40–60% is believed to be desirable. RESULTS The average intact L2–L3 lordosis was 8.5°±2.6° (n=6). With the ALL intact, the 9mm 10° spacer increased lordosis to 10.6°±2.9° (P>0.05). Following ALL resection, use of 11mm 10° and 20° spacers increased lordosis to 14.6°±2.2° and 15.3°±1.8° (P>0.05), respectively. The 13mm 20° and 25° LLIF significantly increased lordosis to 16.7°±2.3° and 16.4°±2.3°, respectively, compared to intact and all constructs prior to ALL release (P CONCLUSIONS This study suggests that LLIF implant lordosis and height can be optimized to mitigate excessive anterior loading while maximizing lordosis correction. Following ALL release, larger spacers with greater posterior heights—not necessarily implant lordosis—may have an increased effect on segmental lordosis while reducing anterior edge loading. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.