Is lumbar facet joint tropism developmental or secondary to degeneration? An international, large-scale multicenter study by the AOSpine Asia Pacific Research Collaboration Consortium

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

General PosterINTRODUCTION: 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

Is lumbar facet joint tropism developmental or secondary to remodeling changes? An international, large-scale multicenter study by the AOSAP collaboration consortium

Session: Free Papers Spine: Degenerative 1: abstract no. 40328INTRODUCTION: Facet joint tropism is asymmetry in orientation of the bilateral facets. Some studies have shown that tropism may increase the risk of disc degeneration and herniations, as well as degenerative spondylolisthesis (DS). It remains controversial whether FJT is a pre-existing developmental phenomena or secondary to progressive joint remodeling. The following study addressed the occurrence of FJT of the lower lumbar spine (i.e. L3-S1) in a degenerative spondylolisthesis patient model. METHODS: This was an international, multi-center cross-sectional study of 267 patients with single level DS recruited from 33 spine institutes in Asia Pacific. FJT (≥8 degrees asymmetry) was assessed on MRI from L3-S1 and in relation to the level of DS. Patient demographic were noted and assessed in relation to FJT of each lumbar segment. RESULTS: 65% were females (mean age of 63 years; mean BMI: 26 kg/m2). FJT was present in 31.3% to 50.6% of DS levels. FJT involved 33.3% to 58.8% of the one or two non-DS levels adjacent to the DS level. Patient demographics were not found to be significantly related to FJT at any level (p>0.05). CONCLUSION: To the authors’ knowledge, this is one of the largest studies conducted, in particular in an Asian population, addressing the “origins concept” of FJT. Although levels with DS were noted to have FJT, adjacent levels with no DS also exhibited tropism and were not related to age and other patient demographics. This study suggested that FJT may have a pre-disposed orientation

Is lumbar facet joint tropism development or secondary to remodeling changes? An international, large-scale multi-centre study by the APSAP collaboration consortium

Session - Free Papers Spine Degenerative 1: abstract no. 40328INTRODUCTION: Facet joint tropism is asymmetry in orientation of the bilateral facets. Some studies have shown that tropism may increase the risk of disc degeneration and herniations, as well as degenerative spondylolisthesis (DS). It remains controversial whether FJT is a pre-existing developmental phenomena or secondary to progressive joint remodeling. The following study addressed the occurrence of FJT of the lower lumbar spine (i.e. L3-S1) in a degenerative spondylolisthesis patient model. METHODS: This was an international, multi-center cross-sectional study of 267 patients with single level DS recruited from 33 spine institutes in Asia Pacific. FJT (≥8 degrees asymmetry) was assessed on MRI from L3-S1 and in relation to the level of DS. Patient demographic were noted and assessed in relation to FJT of each lumbar segment. RESULTS: 65% were females (mean age of 63 years; mean BMI: 26 kg/m2). FJT was present in 31.3% to 50.6% of DS levels. FJT involved 33.3% to 58.8% of the one or two non-DS levels adjacent to the DS level. Patient demographics were not found to be significantly related to FJT at any level (p>0.05). CONCLUSION: To the authors’ knowledge, this is one of the largest studies conducted, in particular in an Asian population, addressing the “origins concept” of FJT. Although levels with DS were noted to have FJT, adjacent levels with no DS also exhibited tropism and were not related to age and other patient demographics. This study suggested that FJT may have a pre-disposed orientation