Journal de la colonne vertébrale

Expandable Titanium Interbody Spacer via Lateral Approach Improves Radiographic and Clinical Outcomes: A 2-Year Follow-up Study

Abstract

Yan Michael Li, Zheng Huang, James Towner, Yan Icy Li, Samantha L Greeley, Amber Edsall and Charles G Ledonio

Introduction: Severe degenerative disc diseases necessitate surgical management with large interbody spacers to regain disc space. Static interbody spacers are the standard of care for minimally invasive lateral lumbar interbody fusion (MIS LLIF). However, using large static interbody spacers requires aggressive endplate preparation prior to implant insertion, which may lead to subsidence and compromised stability. This study describes the clinical and radiographic outcomes of patients treated with expandable interbody spacers following MIS LLIF.

Materials and Methods: This is a single-surgeon, retrospective Institutional Review Board-exempt chart review on 22 consecutive patients who underwent MIS LLIF at 1–2 contiguous level(s) using expandable interbody spacers. Radiographic and clinical functional outcomes were collected and compared at preoperative and postoperative time points up to 24 months. Statistical results were significant if p<0.05.

Results: Twenty-two consecutive patients were evaluated—average age, 57.6 ± 11.0 years; 45.5% were female. Visual Analog Scale (VAS) back and leg pain scores decreased significantly by an average of 7.1 ± 1.2 points at 24 months (p<0.001). Oswestry Disability Index (ODI) scores significantly decreased by a mean of 67.1 ± 10.0 points at 24 months (p<0.001). Lumbar lordosis improved by a mean of 1.8 ± 8.0° at 24 months. Among the 28 spinal levels, 42.9% were at L3–l4 and 39.3% at L4–l5. Anterior, middle, and posterior disc height significantly increased at 24 months by averages of 4.7 ± 3.6, 4.0 ± 3.9, and 1.9 ± 2.4mm, respectively (p<0.001). Neuroforaminal height significantly increased at 24 months by a mean of 2.6 ± 3.7mm (p<0.001). Segmental lordosis significantly improved by 2.5 ± 2.0° at 24 months (p<0.001). There was 100% fusion at all levels, with no cases of radiolucency. One incidence of subsidence (1/28, 3.6%) was reported at 24 months. There were no reported implant-related complications, with 0% pseudoarthrosis and no secondary procedures.

Conclusion: This study showed positive clinical and radiographic outcomes for patients who underwent MIS LLIF with expandable interbody spacers. Sagittal correction and indirect decompression were achieved and maintained up to 24-month follow-up from baseline, based on increased disc height, neuroforaminal height, and segmental lordosis. Functional clinical outcomes significantly improved based on decreased VAS pain and ODI scores at 24 months. The use of lateral expandable spacers was shown to be safe, durable, and effective for the studied patient population.