Lumbar Facet Joint Orientation in Degenerative Spondylolisthesis: the Role of Ethnic Variation in Asia Pacific

Abstract

INTRODUCTION: Lumbar facet joint orien‐ tation has been reported to be associated with the development of degenerative spondylolisthesis (dSpl). The role of ethnici‐ ty regarding facet joint orientation remains uncertain. As such, the following study was performed across a wide‐ranging popula‐ tion base to assess the role of ethnicity in facet joint orientation in patients with dSpl in the Asia Pacific region. METHODS: A multi‐national, multi‐ethnic cross‐sectional image‐based study was per‐ formed in 34 institutions in Asia Pacific, identifying 448 cases. Lateral standing x‐ rays and axial MRIs and/or CT scans were obtained for patients with lumbar dSpl. Magnitude of slip displacement, level of dSpl, and left/right facet joint angulation, width‐curvature ratio, and gap width were noted on image assessment. Facet joint measurements were performed at each level from L3‐S1. Gender, age, BMI, and ethnicity were also noted. RESULTS: The study included 389 patients with known ethnic origin (mean age: 61.4 years; 36.7% males, 63.3% females). The mean BMI was 25.6 kg/m2. The level of dSpl was most prevalent at L4/L5 (72.4%). There were 28.8% Indian, 28.5% Japanese, 17.5% Chinese, 8.2% Korean, 6.2% Thai, 4.6% Cau‐ casian, 2.3% Filipino, 2.3% Malay, and 1.3 were of mixed Asian origin. Accounting for patient demographics and displacement, there was a statistically significant differ‐ ence between ethnicity to that of left/right facet joint angulations, width‐curvature ratios, and gap widths from L3‐S1 between specific ethnic groups (p<0.05). DISCUSSION: This is the largest study to address the role of ethnicity upon lumbar facet joint orientation in dSpl. Ethnicity plays a role in facet joint orientation and may influence the occurrence and severity of dSpl or be a potential consequence. An understanding of ethnic variability may be one factor which assists in identifying those patients at risk of postsurgical development or progression of dSpl.