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Lumbar Facet Joint Orientation in Degenerative Spondylolisthesis: The Role of Ethnic Variation in Asia Pacific—A Study from the AOSAP Research Collaboration

Introduction Degenerative spondylolisthesis (dSpl) can lead to various symptoms, including low back pain. Lumbar facet joint orientation has been reported to be associated with the development of dSpl. The role of ethnicity regarding facet joint orientation remains uncertain. As such, the following study was performed across a wide-ranging population base to assess the role of ethnicity in facet joint orientation in patients with dSpl in the Asia Pacific region. Materials and Methods A multinational, multiethnic cross-sectional image-based study was performed 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% Caucasian, 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 difference 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). Conclusion 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. Acknowledgments This study was funded by AOSpine Asia Pacific. Disclosure of Interest None declared