Association Between Facet Joint Sagittalization and Intervertebral Disc Degeneration: A Retrospective Radiological Analysis

Association Between Facet Joint Sagittalization and Intervertebral Disc Degeneration: A Retrospective Radiological Analysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Association Between Facet Joint Sagittalization and Intervertebral Disc Degeneration: A Retrospective Radiological Analysis Leitao Huang, Zongpo Shi, Chen Zhang, Lei Bi, Lei Qi, Bin Zhang, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7009092/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background To investigate the correlation between sagittalization of lumbar facet joints and lumbar intervertebral disc degeneration (IVDD). Methods Seventy-five patients with low back pain and forty healthy volunteers (control) underwent standard MRI protocols. The basic information of all patients, including age, gender, body mass index, was collected, and the lumbar facet joint angle (LFJA) was measured on lumbar magnetic resonance imaging (MRI), and the lumbar IVDD was assessed by Pfirrmann grading. All data were analyzed statistically. Results Compared with the control group, the LFJA of L3/4, L4/5 and L5/S1 in the patient group were significantly decreased, and there was a statistical difference ( P < 0.05). The lower the segment, the more significant the sagittalization of the facet joints ( P < 0.05). In the patient group, there was a statistically significant difference in the LFJA between the Pfirrmann grades of lumbar IVDD, and there was a strong negative correlation (ρ=-0.736, P < 0.05). Conclusion With the increase of the sagittal degree of LFJA, the IVDD also increases significantly, and this relationship has a strong negative correlation. It is suggested that the sagittalization of facet joints may be an important pathogenic factor of lumbar IVDD. Health sciences/Anatomy Health sciences/Diseases Health sciences/Health care Health sciences/Medical research lumbar intervertebral disc intervertebral disc degeneration lumbar facet joint angle facet joint sagittalization Figures Figure 1 Figure 2 Figure 3 Figure 4 Background Epidemiological studies indicate that 65–80% of the general population will experience low back pain (LBP) during their lifetime [ 1 ] . As the most prevalent chronic pain syndrome, LBP represents the primary cause of lumbar mobility impairment in individuals aged < 45 years [ 2 ] . Degenerative lumbar spine disorders constitute the most frequent etiology of LBP [ 3 ] . Current research demonstrates that LBP associated with lumbar intervertebral disc degeneration (IVDD) involves multifactorial pathogenesis, including but not limited to: advanced age, elevated body mass index, occupational mechanical loading, history of lumbar trauma, and genetic predisposition [ 4 , 5 ] . While lumbar disc degeneration may coexist with other spinal conditions like IVD herniation, spinal stenosis, and spondylolisthesis in clinical practice, these represent distinct pathological entities rather than a single disease spectrum [ 6 ] . Current research priorities in this field focus on the relationship between disc degeneration and ligament properties, though comprehensive epidemiological data on scholarly focus areas remain limited.. Emerging evidence indicates that lumbar facet joint arthritis contributes to approximately 15–45% of chronic LBP cases [ 7 ] , demonstrating a direct pathophysiological relationship with facet joint degeneration. Contemporary research has established facet joint asymmetry as a reliable quantitative biomarker for assessing degenerative changes in facet joints [ 8 , 9 ] . Furthermore, recent biomechanical studies suggest that facet joint degeneration may serve as both a consequence and potential initiator of lumbar IVDD [ 4 ] , highlighting the complex interplay within the three-joint complex. Intervertebral disc degeneration (IVDD) represents a multifactorial pathological process whose precise mechanisms remain incompletely understood [ 10 ] . Current research by Youn et al. [ 11 ] identified several key contributing factors, including abnormal biomechanical loading, nutritional deficiency, cellular apoptosis, inflammatory cytokines, and matrix-degrading enzymes. Notably, in vitro studies demonstrate that combined administration of insulin-like growth factor (IGF) and platelet-derived growth factor (PDGF) can significantly attenuate apoptotic rates in degenerating discs [ 12 ] . From a biomechanical perspective, the intervertebral disc serves three primary functions: (1) maintaining intervertebral space height, (2) resisting axial compressive forces, and (3) limiting segmental motion within a physiological, pain-free range [ 13 ] . Disruption of normal mechanical loading patterns, particularly through excessive axial forces or traumatic injury, has been established as a principal pathogenic factor in IVDD development [ 14 ] . Emerging evidence further suggests a significant association between facet joint sagittal orientation changes and IVDD progression, highlighting the intricate relationship between anterior and posterior spinal elements in degenerative processes [ 15 ] . Previous research has established that morphological and positional changes in lumbar facet joints result from multiple pathological factors, including facet joint osteoarthritis and IVDD [ 16 ] . While numerous studies have investigated the relationship between lumbar facet joint characteristics and IVDD, the specific association between facet joint sagittalization and IVDD severity remains controversial [ 17 , 18 ] . To address this knowledge gap, the present study employs lumbar facet joint angle (LFJA) as a key morphological parameter to systematically examine its correlation with IVDD progression. Methods Study participants This study was performed after the approval of our Institutional Review Board. All subjects provided the informed consent. This retrospective study analyzed data from 200 patients with lumbar IVDD treated between April 2019 and March 2020. According to the inclusion and exclusion criteria, a total of 75 patients were finally selected as the patient group, 40 healthy volunteers served as the control group. Inclusion criteria: patients with LBP over 6 months; age over 18 years; body mass index (BMI) 18.5–24.9 kg/m 2 ; all subjects underwent MRI scans. Exclusion criteria: lumbar tuberculosis, lumbar intervertebral discitis and lumbar osteomyelitis; severe lumbar congenital dysplasia; spinal tumor, lumbar diffuse metastases; history of lumbar surgery or lumbar fracture trauma; patients with abnormal muscle signal or sacroiliac joint lesions; patients with lumbar disc herniation; patients with IVDD in other spinal segments; patients with mental disorders. Imaging parameters Both groups of subjects underwent lumbar spine magnetic resonance imaging (MRI) scans using a MAGNETOM Trio 3.0 T MRI scanner (Tim Trio, Siemens Medical Solutions, Erlangen, Germany). The subjects were in the supine position, and the scanning range was from three IVD segments (L3/L4, L4/5, L5/S1), and a total of 345 IVD were scanned. Scanning conditions: pulse repetition time (TR) 575 ms, echo time (TE) 18.5 ms, field of view (FOV) 160 mm × 160 mm, voxel size 0.4 mm × 0.4 mm × 4.0 mm, slice spacing 0.3 mm. Morphological evaluation of IVD with axial T2-weighted images (T2WI). Facet joint angle measurement That is, the lumbar facet joint angle (LFJA) between the line connecting the anterior and posterior end points of the facet joint on this segment and the midsagittal line of the same vertebral body [1] (Fig. 1 ). Taking 45° as the limit, the angle greater than 45° was regarded as the deviation of the coronal plane, and the angle less than 45° was regarded as the deviation of the sagittal plane, and the LFJA of L3/4, L4/5 and L5/S1 of all subjects were measured. Grading of intervertebral disc degeneration The heights of L3/4, L4/5, and L5/S1 IVD were measured on the sagittal plane of MRI. A 25% reduction in the height of the adjacent normal IVD was defined as a low IVD height (Table 1 ). In order to further exclude subjective factors and better reflect the phenomenon, we redefine the modified Pfirrmann classification according to the signal changes of IVDD and the changes of IVD height (Fig. 2 ) [ 19 ] : divided into 4 grades: grade I, Pfirrmann 1; grade II, Pfirrmann 2 to 3, based on signal of nucleus pulposus and inner annulus; grade III, Pfirrmann 4 to 5, based on outer fibers signal of the annulus; grade IV, Pfirrmann 6 to 8, based on IVD height loss. Table 1 Modified Pfirrmann classification of LIDD by MRI Grade Signal intensity of nucleus pulposus and inner fibrosus annulus Difference signal between rear and inner and outer fibrosus annulus LIDD height 1 Uniform high signal, and cerebrospinal fluid signal quite Obvious Normal 2 High signal (stronger than sacral fat less than CSF) Obvious Normal 3 Or high signal and there are cracks in the nucleus pulposus Obvious Normal 4 High signal (less than presacral fat) Not obvious Normal 5 Low signal (equal to outer fibrosus annulus) Not obvious Normal 6 Low signal Not obvious Reduce 60% Image assessment All imaging parameters were measured and evaluated by two experienced specialists. The measurement was completed by two members independently, and each parameter repeat the measurement twice and take the mean value as the LFJA of this patient. Statistical analysis All data were statistically analyzed using SPSS version 23.0 (SPSS, IBM, Armonk, NY). Measurement data were expressed as mean ± standard deviation, independent samples t test was used for comparison between two groups; one-way ANOVA was used for comparison between multiple groups, and LSD or Tamhane's T2 test was used for pairwise comparison; χ 2 test was used for comparison of enumeration data between groups; The correlation between LFJA and Pfirrmann grade was analyzed by Pearson correlation coefficient. Correlations were considered strong for ρ > 0.7, moderate for 0.5 < ρ < 0.7, and weak for ρ < 0.5. The test level was α = 0.05, and P < 0.05 was considered statistically significant. Results There were 75 patients in the patient group (42/33 males/females). The mean age was 58.1 ± 12.1 years (range 31–85 years). A total of 40 healthy volunteers were included in the control group (21/19 males/females). The mean age was 55.8 ± 14.4 years (range 29–82 years). There was no significant difference in gender and age between the two groups ( χ 2 = 0.129, P = 0.719; t = 0.885, P = 0.378). The mean BMI was 22.16 ± 1.6 kg/m 2 in the patient group (range 18.5–24.5) and 21.6 ± 1.5 kg/m 2 in the control group (range 18.7–24.8), there was no statistical difference between the two groups ( t = 1.878, P = 0.063). Statistical analysis showed that the LFJA of each segment in the patient group were significantly smaller than those in the control group (Table 2 ); In the patient group, as the lumbar segment were lower, the LFJA gradually decreased, which was statistically significant ( P < 0.01), as shown in (Fig. 3 ). Table 2 Comparative analysis of lumbar facet joint angle between two groups of patients Variables Patient group (n = 75) Control group(n = 40) t value P value L3/4 LFJA (°) 42.4 ± 1.9 44.7 ± 1.3 -7.770 0.000 *** L4/5 LFJA (°) 36.9 ± 2.2 45.0 ± 1.6 -22.612 0.000 *** L5S1 LFJA (°) 30.6 ± 2.1 45.1 ± 1.4 -42.048 0.000 *** LFJA lumbar facet joint angle; *** P 0.05, indicating that the homogeneity of variance. Therefore, the LSD test was used for the pairwise comparative analysis of the LFJA between all levels in the patient group. Among them, there were significant differences in LFJA between grades I vs. III, grades I vs. IV, grades II vs. III, grades II vs. IV, and grades III vs. IV ( P 0.05, Table 3 ). Table 3 Analysis on the difference of facet angle in different grades of lumbar disc degeneration in case group Grade N(%) LFJA (°) Minimum-Maximum I 40 41.3 ± 3.1 33.1 ~ 45.6 II 71 40.0 ± 4.0 29.7 ~ 45.2 III 62 36.1 ± 3.1 28.1 ~ 41.4 IV 52 30.9 ± 2.8 27.4 ~ 40.2 Patients (A) Patients (B) P value 95% CI I II 0.342 -0.575 ~ 3.119 III 0.000 *** 3.554 ~ 6.944 IV 0.000 *** 8.714 ~ 12.136 II III 0.000 *** 2.341 ~ 5.612 IV 0.000 *** 7.501 ~ 10.806 III IV 0.000 *** 3.700 ~ 6.653 LFJA lumbar facet joint angle; *** P < 0.001. The correlation between LFJA and Pfirrmann grade was analyzed by Pearson correlation coefficient. After statistical analysis, it was found that with the increase of the Pfirrmann grade of the IVD, the degree of sagittalization of the LFJA became more significant, and there was a strong negative correlation between them (ρ = − 0.736, P < 0.01) Fig. 4 . Consistency comparison of IVDD grade and LFJA between groups. The inter-group agreement between Pfirrmann grades of lumbar discs was good (Cranbach's α = -0.799), especially for grade I (Cronbach's α = -0.858). The inter-group consistency of LFJA was good (Cranbach's α = -0.752). Discussion From biomechanical and anatomical perspectives, the intervertebral disc (IVD) and its corresponding facet joints constitute a "three-joint complex" that serves as the fundamental functional unit of the spinal motion system [ 20 ] . The IVD performs crucial functions including load distribution, shock absorption, and maintenance of spinal stability. Disruption of this mechanical equilibrium inevitably compromises spinal stability and kinematic function [ 21 ] . Such impairment may propagate to adjacent spinal segments, potentially affecting overall spinal stability and movement capacity. Previous studies have shown that sagittal orientation of facet joints is associated with vertebral anterolisthesis in degenerative lumbar spines. Additionally, the severity and segmental level of slippage may further contribute to facet joint instability [ 22 ] . Current research presents three distinct perspectives on the relationship between lumbar intervertebral disc degeneration (IVDD) and facet joint degeneration: Huang et al. [ 23 ] proposed a bidirectional causal relationship between facet joint degeneration and IVDD throughout the lumbar degenerative process, with both natural aging and abnormal mechanical loading serving as primary pathogenic factors. Wang et al. [ 24 ] postulated that lumbar degeneration initiates from facet joint degeneration, creating a reciprocal interaction between facet joint and disc degeneration. Their findings suggest that while both processes progress with age, IVDD eventually outpaces facet joint degeneration in later stages. Alternative theories contend that lumbar degeneration originates from IVDD [ 25 ] . According to this view, disc dehydration and height reduction alter facet joint biomechanics, subsequently inducing facet joint degeneration. In 2001, Pfirrmann et al. [ 26 ] established a grading system for IVDD based on MRI characteristics including disc signal intensity, internal structure, nucleus pulposus-annulus fibrosus demarcation, and disc height. This system demonstrated high reliability (kappa = 0.69–0.90).In the current study, we adopted a modified Pfirrmann classification. This modified classification scheme was implemented to minimize subjective assessment variability while enhancing discriminative capacity between degeneration stages. This study demonstrated significantly smaller LFJA in the patient group compared to controls across all vertebral segments (P < 0.01). Within the patient cohort, LFJA showed progressive reduction in more caudal segments (P 0.05). Pearson correlation analysis revealed a strong negative association (ρ = -0.736, P < 0.001) between increasing Pfirrmann grades and decreasing LFJA values, indicating greater facet joint sagittalization with advancing disc degeneration. These findings strongly suggest: (1) a close relationship between facet joint sagittalization and IVDD severity, and (2) that facet joint sagittalization may represent a primary pathogenic factor in IVDD development. According to the results obtained in this study, we analyzed its main mechanism in two points: First, the "three-joint complex" formed by the IVD and the facet joints on both sides-This special structure plays a very important role in maintaining and stabilizing the balance and coordination of lumbar spine activities [ 20 , 22 ] . Abnormalities in any one part will affect the other two parts and thus the whole. The lumbar IVD of the patients in this study group all have different degrees of degeneration. The earliest due to the IVDD changes, the intervertebral space is narrowed, the height of the IVD is lost, and the lumbar vertebral is unstable, which further causes local load bearing on the facet joints [ 27 ] . As a result, the stress-increasing site are more prone to bone hyperplasia, and the stress-reduced site is more prone to osteoporosis, accompanied by the existence of corresponding soft tissue repair and reconstruction, and finally the sagittal change of the facet joints [ 28 ] . Second, there are different biomechanical factors in L4/5 and L5/S1 IVDD. The degeneration of the L4/5 IVD is mainly related to the way of rotational movement, and the morphological basis of the L4/5 facet joint is the curved articular surface [ 29 ] . The degeneration of the L5/S1 IVD is mainly related to the stability of the spine and the gravitational load. The L5/S1 facet joint typically has a flatter and more coronally oriented articular surface compared to upper lumbar levels [23].. In the lumbar spine, facet joints are more sagittally oriented in higher segments (e.g., L4-L5) compared to lower segments (e.g., L5-S1). This anatomical variation reduces their ability to resist shear forces, resulting in stress concentration during load transmission. Consequently, the L5/S1 facet joints experience increased gravitational and shear loads, which may impair their function over time. Progressive facet degeneration and ligamentous instability can then promote abnormal spinal motion, further accelerating IVDD [ 30 ] . This study has several limitations: First, as a retrospective study, it is subject to inherent biases associated with this design. Second, potential confounding factors such as occupation, smoking history, age, and body mass index were not accounted for in analyzing the relationship between LFJA and IVDD, which may affect the observed associations [ 24 , 27 ] . Finally, while this study provides important insights into the association between facet joint parameters and IVDD at L3/4, L4/5, and L5/S1 levels, future research should include more intervertebral segments and additional influencing factors for more comprehensive analysis. Conclusions In this study, we analyzed Pfirrmann degeneration grades for three intervertebral discs (L3/4, L4/5, and L5/S1) using MRI and measured the lumbar facet joint angles (LFJA) of corresponding vertebral segments. Our findings confirm a significant association between LFJA and IVDD. The study demonstrates a strong negative correlation between IVDD severity and the degree of lumbar facet joint sagittalization. This relationship was particularly evident in the lower lumbar vertebrae (L4/5 and L5/S1). These findings provide valuable theoretical insights that may inform clinical understanding of lumbar IVDD pathogenesis and guide treatment strategies. Abbreviations BMI Body mass index LBP Low back pain LFJA Lumbar facet joint angle IVD Intervertebral disc IVDD Intervertebral disc degeneration MRI Magnetic resonance imaging FOV Field of view T2Wis T2-weighted images TE Echo time TR Repetition time. Declarations Funding This study was supported by the Science and Technology Development Fund of Nanjing Medical University (No. NMUB20220153), and the Youth Exploration Project Fund of the Fourth Affiliated Hospital of Nanjing Medical University (No. 23YJRC27) Availability of data and materials The data supporting our findings can be found in the article. Authors’ contributions LTH designed and performed the study, and wrote and edited the manuscript. ZPS revised the manuscript, conceived and designed the study. JC analyzed and interpreted the data. CZ revised the manuscript. LB and LQ assisted with data presentation and drafting of the manuscript. BZ and JC conceived and designed the study, and assisted with the research, drafting, and revision of the manuscript. All authors read and approved the final manuscript. Declarations: Competing interests No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript. Ethics approval and consent to participate The experimental protocol was established according to the ethical guidelines of the Helsinki Declaration and was approved by the Human Ethics Committee of Fourth Affiliated Hospital of Nanjing Medical University. Written informed consent was obtained from all participants. Consent for publication All authors have read this article and agree to publish. References Chepurin, D. et al. Bony stress in the lumbar spine is associated with intervertebral disc degeneration and low back pain: a retrospective case-control MRI study of patients under 25 years of age. Eur. Spine J. 28 (11), 2470–2477 (2019). 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7009092","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":482444635,"identity":"1ddaf26b-c224-4629-87c9-756862fe1dfc","order_by":0,"name":"Leitao Huang","email":"","orcid":"","institution":"Fourth Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Leitao","middleName":"","lastName":"Huang","suffix":""},{"id":482444636,"identity":"1ced612a-dbab-4697-9c61-1e5a4e3361a0","order_by":1,"name":"Zongpo Shi","email":"","orcid":"","institution":"Fourth Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Zongpo","middleName":"","lastName":"Shi","suffix":""},{"id":482444637,"identity":"37853eb5-84b2-40d2-8798-5c0103c2ace7","order_by":2,"name":"Chen Zhang","email":"","orcid":"","institution":"Fourth Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Chen","middleName":"","lastName":"Zhang","suffix":""},{"id":482444639,"identity":"747f93a8-aef2-4481-8b0a-eee8b4606eb5","order_by":3,"name":"Lei Bi","email":"","orcid":"","institution":"Fourth Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Lei","middleName":"","lastName":"Bi","suffix":""},{"id":482444642,"identity":"9e0d4007-dac4-410b-8831-cd0a8a6f2617","order_by":4,"name":"Lei Qi","email":"","orcid":"","institution":"Fourth Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Lei","middleName":"","lastName":"Qi","suffix":""},{"id":482444644,"identity":"603ba06a-aa11-4592-ab81-72b76a7020a4","order_by":5,"name":"Bin Zhang","email":"","orcid":"","institution":"Fourth Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Bin","middleName":"","lastName":"Zhang","suffix":""},{"id":482444646,"identity":"5ff4750f-ba6b-4318-9fd6-2ba89cbe193a","order_by":6,"name":"Ji Chen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYDACCRA2YGZmYG9sfPiBNC08h5uNJYjWwsDADGSktwnwEKODf3bzsQcWBdbsfDcftgH128npNhCy5M6xdAMJg3RmyduJbQ8KGJKNzQ4Q0GIgkWMmIWFwmNngdmK7gQTDgcRthLXkf4NouXmwTYKHOC05bBAtNxiJ1CJxIw3kMKBfziQCA9mACL/wz0h+Ji3xxzqZ7/jxhw8/VNjJEdQCAszAuElmAKs0IEI5CDAC04kdAzGGj4JRMApGwcgEAPDlPai5e36rAAAAAElFTkSuQmCC","orcid":"","institution":"Fourth Affiliated Hospital of Nanjing Medical University","correspondingAuthor":true,"prefix":"","firstName":"Ji","middleName":"","lastName":"Chen","suffix":""}],"badges":[],"createdAt":"2025-06-30 09:53:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7009092/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7009092/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86421007,"identity":"0062992d-b6af-4f13-9a7a-3efe88d589f9","added_by":"auto","created_at":"2025-07-10 12:48:49","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":594165,"visible":true,"origin":"","legend":"\u003cp\u003eExamples of facet joint angles measured on sagittal and corresponding cross-sectional images of T2W axial lumbar MRI are shown. (A)-(C) Illustration of facet joint measurements for L3/4, L4/5, and L5S1, respectively.\u003c/p\u003e","description":"","filename":"Fig.1.png","url":"https://assets-eu.researchsquare.com/files/rs-7009092/v1/10edbbe4448518eda5c8b5f9.png"},{"id":86421002,"identity":"8372320a-c98d-4180-a5d5-d6b2e647c148","added_by":"auto","created_at":"2025-07-10 12:48:49","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":421008,"visible":true,"origin":"","legend":"\u003cp\u003eIllustration of Pfifirrmann grading on MRI of different lumbar IVDD.\u003c/p\u003e","description":"","filename":"Fig.2.png","url":"https://assets-eu.researchsquare.com/files/rs-7009092/v1/47f4b18e89e1121ff6c7b0e8.png"},{"id":86421003,"identity":"7c8eb0b9-3671-469a-8ad8-0373500ce560","added_by":"auto","created_at":"2025-07-10 12:48:49","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":31252,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of LFJA of lumbar different segments in patients. The LFJA of L3/4 were significantly different from those of L4/5 and L5/S1, respectively (L3/4 vs. L4/5: 42.4 ± 1.9° vs. 36.9 ± 2.2°; L3/4 vs. L5/S1: 42.4 ± 1.9° vs. 30.6±2.1°) (\u003csup\u003e**\u003c/sup\u003e, \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01); The LFJA of L5/S1 was significantly lower than that of L4/5, and the difference was statistically significant (30.6±2.1° vs. 36.9 ± 2.2°, \u003csup\u003e##\u003c/sup\u003e, \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01).\u003c/p\u003e","description":"","filename":"Fig.3.png","url":"https://assets-eu.researchsquare.com/files/rs-7009092/v1/11c28df6cd06a9b5a8a47d86.png"},{"id":86422157,"identity":"4aff7006-bc1b-4123-a6cc-0536f82cf505","added_by":"auto","created_at":"2025-07-10 12:56:49","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":72918,"visible":true,"origin":"","legend":"\u003cp\u003eScatter plots and linear regression lines indicating correlations between a LFJA value (°) and Pfirrmann grade:the LFJA value and grade I-IV (ρ = –0.736, \u003cem\u003eP \u003c/em\u003e= 0.000).\u003c/p\u003e","description":"","filename":"Fig.4.png","url":"https://assets-eu.researchsquare.com/files/rs-7009092/v1/05db2f2f2c8c3f95c1c305ed.png"},{"id":88021474,"identity":"f55cf8a0-2493-4d95-8b34-529cfc62aded","added_by":"auto","created_at":"2025-07-31 13:54:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2215236,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7009092/v1/43dc3441-b9f8-45d7-b11c-172cb7adf864.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Association Between Facet Joint Sagittalization and Intervertebral Disc Degeneration: A Retrospective Radiological Analysis","fulltext":[{"header":"Background","content":"\u003cp\u003eEpidemiological studies indicate that 65\u0026ndash;80% of the general population will experience low back pain (LBP) during their lifetime\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. As the most prevalent chronic pain syndrome, LBP represents the primary cause of lumbar mobility impairment in individuals aged\u0026thinsp;\u0026lt;\u0026thinsp;45 years\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. Degenerative lumbar spine disorders constitute the most frequent etiology of LBP\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. Current research demonstrates that LBP associated with lumbar intervertebral disc degeneration (IVDD) involves multifactorial pathogenesis, including but not limited to: advanced age, elevated body mass index, occupational mechanical loading, history of lumbar trauma, and genetic predisposition\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e. While lumbar disc degeneration may coexist with other spinal conditions like IVD herniation, spinal stenosis, and spondylolisthesis in clinical practice, these represent distinct pathological entities rather than a single disease spectrum\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. Current research priorities in this field focus on the relationship between disc degeneration and ligament properties, though comprehensive epidemiological data on scholarly focus areas remain limited..\u003c/p\u003e\u003cp\u003eEmerging evidence indicates that lumbar facet joint arthritis contributes to approximately 15\u0026ndash;45% of chronic LBP cases\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e, demonstrating a direct pathophysiological relationship with facet joint degeneration. Contemporary research has established facet joint asymmetry as a reliable quantitative biomarker for assessing degenerative changes in facet joints\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e. Furthermore, recent biomechanical studies suggest that facet joint degeneration may serve as both a consequence and potential initiator of lumbar IVDD\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e, highlighting the complex interplay within the three-joint complex. Intervertebral disc degeneration (IVDD) represents a multifactorial pathological process whose precise mechanisms remain incompletely understood\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. Current research by Youn et al.\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e identified several key contributing factors, including abnormal biomechanical loading, nutritional deficiency, cellular apoptosis, inflammatory cytokines, and matrix-degrading enzymes. Notably, in vitro studies demonstrate that combined administration of insulin-like growth factor (IGF) and platelet-derived growth factor (PDGF) can significantly attenuate apoptotic rates in degenerating discs \u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eFrom a biomechanical perspective, the intervertebral disc serves three primary functions: (1) maintaining intervertebral space height, (2) resisting axial compressive forces, and (3) limiting segmental motion within a physiological, pain-free range\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. Disruption of normal mechanical loading patterns, particularly through excessive axial forces or traumatic injury, has been established as a principal pathogenic factor in IVDD development\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. Emerging evidence further suggests a significant association between facet joint sagittal orientation changes and IVDD progression, highlighting the intricate relationship between anterior and posterior spinal elements in degenerative processes\u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003ePrevious research has established that morphological and positional changes in lumbar facet joints result from multiple pathological factors, including facet joint osteoarthritis and IVDD\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e. While numerous studies have investigated the relationship between lumbar facet joint characteristics and IVDD, the specific association between facet joint sagittalization and IVDD severity remains controversial\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. To address this knowledge gap, the present study employs lumbar facet joint angle (LFJA) as a key morphological parameter to systematically examine its correlation with IVDD progression.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy participants\u003c/h2\u003e\u003cp\u003e This study was performed after the approval of our Institutional Review Board. All subjects provided the informed consent.\u003c/p\u003e\u003cp\u003eThis retrospective study analyzed data from 200 patients with lumbar IVDD treated between April 2019 and March 2020. According to the inclusion and exclusion criteria, a total of 75 patients were finally selected as the patient group, 40 healthy volunteers served as the control group.\u003c/p\u003e\u003cp\u003eInclusion criteria: patients with LBP over 6 months; age over 18 years; body mass index (BMI) 18.5\u0026ndash;24.9 kg/m\u003csup\u003e2\u003c/sup\u003e; all subjects underwent MRI scans.\u003c/p\u003e\u003cp\u003eExclusion criteria: lumbar tuberculosis, lumbar intervertebral discitis and lumbar osteomyelitis; severe lumbar congenital dysplasia; spinal tumor, lumbar diffuse metastases; history of lumbar surgery or lumbar fracture trauma; patients with abnormal muscle signal or sacroiliac joint lesions; patients with lumbar disc herniation; patients with IVDD in other spinal segments; patients with mental disorders.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eImaging parameters\u003c/h3\u003e\n\u003cp\u003eBoth groups of subjects underwent lumbar spine magnetic resonance imaging (MRI) scans using a MAGNETOM Trio 3.0 T MRI scanner (Tim Trio, Siemens Medical Solutions, Erlangen, Germany). The subjects were in the supine position, and the scanning range was from three IVD segments (L3/L4, L4/5, L5/S1), and a total of 345 IVD were scanned. Scanning conditions: pulse repetition time (TR) 575 ms, echo time (TE) 18.5 ms, field of view (FOV) 160 mm \u0026times; 160 mm, voxel size 0.4 mm \u0026times; 0.4 mm \u0026times; 4.0 mm, slice spacing 0.3 mm. Morphological evaluation of IVD with axial T2-weighted images (T2WI).\u003c/p\u003e\n\u003ch3\u003eFacet joint angle measurement\u003c/h3\u003e\n\u003cp\u003eThat is, the lumbar facet joint angle (LFJA) between the line connecting the anterior and posterior end points of the facet joint on this segment and the midsagittal line of the same vertebral body [1] (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Taking 45\u0026deg; as the limit, the angle greater than 45\u0026deg; was regarded as the deviation of the coronal plane, and the angle less than 45\u0026deg; was regarded as the deviation of the sagittal plane, and the LFJA of L3/4, L4/5 and L5/S1 of all subjects were measured.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eGrading of intervertebral disc degeneration\u003c/h3\u003e\n\u003cp\u003eThe heights of L3/4, L4/5, and L5/S1 IVD were measured on the sagittal plane of MRI. A 25% reduction in the height of the adjacent normal IVD was defined as a low IVD height (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). In order to further exclude subjective factors and better reflect the phenomenon, we redefine the modified Pfirrmann classification according to the signal changes of IVDD and the changes of IVD height (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) \u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e: divided into 4 grades: grade I, Pfirrmann 1; grade II, Pfirrmann 2 to 3, based on signal of nucleus pulposus and inner annulus; grade III, Pfirrmann 4 to 5, based on outer fibers signal of the annulus; grade IV, Pfirrmann 6 to 8, based on IVD height loss.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eModified Pfirrmann classification of LIDD by MRI\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGrade\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSignal intensity of nucleus pulposus and inner fibrosus annulus\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDifference signal between rear and inner and outer fibrosus annulus\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLIDD height\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eUniform high signal, and cerebrospinal fluid signal quite\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eObvious\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNormal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHigh signal (stronger than sacral fat less than CSF)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eObvious\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNormal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOr high signal and there are cracks in the nucleus pulposus\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eObvious\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNormal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHigh signal (less than presacral fat)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot obvious\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNormal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLow signal (equal to outer fibrosus annulus)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot obvious\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNormal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLow signal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot obvious\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eReduce\u0026thinsp;\u0026lt;\u0026thinsp;30%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLow signal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot obvious\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eReduce 30%\u0026sim;60%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLow signal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot obvious\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eReduce\u0026thinsp;\u0026gt;\u0026thinsp;60%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eImage assessment\u003c/h3\u003e\n\u003cp\u003eAll imaging parameters were measured and evaluated by two experienced specialists. The measurement was completed by two members independently, and each parameter repeat the measurement twice and take the mean value as the LFJA of this patient.\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eAll data were statistically analyzed using SPSS version 23.0 (SPSS, IBM, Armonk, NY). Measurement data were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation, independent samples \u003cem\u003et\u003c/em\u003e test was used for comparison between two groups; one-way ANOVA was used for comparison between multiple groups, and LSD or Tamhane's T2 test was used for pairwise comparison; \u003cem\u003eχ\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e test was used for comparison of enumeration data between groups; The correlation between LFJA and Pfirrmann grade was analyzed by Pearson correlation coefficient. Correlations were considered strong for ρ\u0026thinsp;\u0026gt;\u0026thinsp;0.7, moderate for 0.5\u0026thinsp;\u0026lt;\u0026thinsp;ρ\u0026thinsp;\u0026lt;\u0026thinsp;0.7, and weak for ρ\u0026thinsp;\u0026lt;\u0026thinsp;0.5. The test level was α\u0026thinsp;=\u0026thinsp;0.05, and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThere were 75 patients in the patient group (42/33 males/females). The mean age was 58.1\u0026thinsp;\u0026plusmn;\u0026thinsp;12.1 years (range 31\u0026ndash;85 years). A total of 40 healthy volunteers were included in the control group (21/19 males/females). The mean age was 55.8\u0026thinsp;\u0026plusmn;\u0026thinsp;14.4 years (range 29\u0026ndash;82 years). There was no significant difference in gender and age between the two groups (\u003cem\u003eχ\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.129, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.719; \u003cem\u003et\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.885, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.378). The mean BMI was 22.16\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 kg/m\u003csup\u003e2\u003c/sup\u003e in the patient group (range 18.5\u0026ndash;24.5) and 21.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 kg/m\u003csup\u003e2\u003c/sup\u003e in the control group (range 18.7\u0026ndash;24.8), there was no statistical difference between the two groups (\u003cem\u003et\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.878, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.063).\u003c/p\u003e\u003cp\u003eStatistical analysis showed that the LFJA of each segment in the patient group were significantly smaller than those in the control group (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e); In the patient group, as the lumbar segment were lower, the LFJA gradually decreased, which was statistically significant (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01), as shown in (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparative analysis of lumbar facet joint angle between two groups of patients\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariables\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePatient group (n\u0026thinsp;=\u0026thinsp;75)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eControl group(n\u0026thinsp;=\u0026thinsp;40)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eL3/4 LFJA (\u0026deg;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e42.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e44.7\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-7.770\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.000\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eL4/5 LFJA (\u0026deg;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e36.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e45.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-22.612\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.000\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eL5S1 LFJA (\u0026deg;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e30.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e45.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-42.048\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.000\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eLFJA\u003c/em\u003e lumbar facet joint angle; \u003csup\u003e***\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe homogeneity of variance of the facet joint angles in the patient group was tested by Levene in the analysis of variance. The result showed that the Levene value\u0026thinsp;=\u0026thinsp;2.19, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.089\u0026thinsp;\u0026gt;\u0026thinsp;0.05, indicating that the homogeneity of variance. Therefore, the LSD test was used for the pairwise comparative analysis of the LFJA between all levels in the patient group. Among them, there were significant differences in LFJA between grades I vs. III, grades I vs. IV, grades II vs. III, grades II vs. IV, and grades III vs. IV (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There was no significant difference in facet joint angle between grade I and grade II (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05, Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eAnalysis on the difference of facet angle in different grades of lumbar disc degeneration in case group\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGrade\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eN(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eLFJA (\u0026deg;)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMinimum-Maximum\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e41.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e33.1\u0026thinsp;~\u0026thinsp;45.6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eII\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e40.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e29.7\u0026thinsp;~\u0026thinsp;45.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIII\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e36.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e28.1\u0026thinsp;~\u0026thinsp;41.4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIV\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e27.4\u0026thinsp;~\u0026thinsp;40.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePatients (A)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePatients (B)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eII\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.342\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-0.575\u0026thinsp;~\u0026thinsp;3.119\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIII\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.000\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.554\u0026thinsp;~\u0026thinsp;6.944\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIV\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.000\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e8.714\u0026thinsp;~\u0026thinsp;12.136\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eII\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIII\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.000\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.341\u0026thinsp;~\u0026thinsp;5.612\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIV\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.000\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7.501\u0026thinsp;~\u0026thinsp;10.806\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIII\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIV\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.000\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.700\u0026thinsp;~\u0026thinsp;6.653\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003eLFJA\u003c/em\u003e lumbar facet joint angle; \u003csup\u003e***\u003c/sup\u003e\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe correlation between LFJA and Pfirrmann grade was analyzed by Pearson correlation coefficient. After statistical analysis, it was found that with the increase of the Pfirrmann grade of the IVD, the degree of sagittalization of the LFJA became more significant, and there was a strong negative correlation between them (ρ = \u0026minus;\u0026thinsp;0.736, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01) Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eConsistency comparison of IVDD grade and LFJA between groups. The inter-group agreement between Pfirrmann grades of lumbar discs was good (Cranbach's α = -0.799), especially for grade I (Cronbach's α = -0.858). The inter-group consistency of LFJA was good (Cranbach's α = -0.752).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eFrom biomechanical and anatomical perspectives, the intervertebral disc (IVD) and its corresponding facet joints constitute a \"three-joint complex\" that serves as the fundamental functional unit of the spinal motion system\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e. The IVD performs crucial functions including load distribution, shock absorption, and maintenance of spinal stability. Disruption of this mechanical equilibrium inevitably compromises spinal stability and kinematic function\u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e. Such impairment may propagate to adjacent spinal segments, potentially affecting overall spinal stability and movement capacity.\u003c/p\u003e\u003cp\u003ePrevious studies have shown that sagittal orientation of facet joints is associated with vertebral anterolisthesis in degenerative lumbar spines. Additionally, the severity and segmental level of slippage may further contribute to facet joint instability\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. Current research presents three distinct perspectives on the relationship between lumbar intervertebral disc degeneration (IVDD) and facet joint degeneration: Huang et al.\u003csup\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e proposed a bidirectional causal relationship between facet joint degeneration and IVDD throughout the lumbar degenerative process, with both natural aging and abnormal mechanical loading serving as primary pathogenic factors. Wang et al.\u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e postulated that lumbar degeneration initiates from facet joint degeneration, creating a reciprocal interaction between facet joint and disc degeneration. Their findings suggest that while both processes progress with age, IVDD eventually outpaces facet joint degeneration in later stages. Alternative theories contend that lumbar degeneration originates from IVDD\u003csup\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e. According to this view, disc dehydration and height reduction alter facet joint biomechanics, subsequently inducing facet joint degeneration.\u003c/p\u003e\u003cp\u003eIn 2001, Pfirrmann et al.\u003csup\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/sup\u003e established a grading system for IVDD based on MRI characteristics including disc signal intensity, internal structure, nucleus pulposus-annulus fibrosus demarcation, and disc height. This system demonstrated high reliability (kappa\u0026thinsp;=\u0026thinsp;0.69\u0026ndash;0.90).In the current study, we adopted a modified Pfirrmann classification. This modified classification scheme was implemented to minimize subjective assessment variability while enhancing discriminative capacity between degeneration stages.\u003c/p\u003e\u003cp\u003eThis study demonstrated significantly smaller LFJA in the patient group compared to controls across all vertebral segments (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Within the patient cohort, LFJA showed progressive reduction in more caudal segments (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01). According to Pfirrmann classification (note: corrected spelling), no significant LFJA difference was observed between grades I and II (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Pearson correlation analysis revealed a strong negative association (ρ = -0.736, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) between increasing Pfirrmann grades and decreasing LFJA values, indicating greater facet joint sagittalization with advancing disc degeneration. These findings strongly suggest: (1) a close relationship between facet joint sagittalization and IVDD severity, and (2) that facet joint sagittalization may represent a primary pathogenic factor in IVDD development.\u003c/p\u003e\u003cp\u003eAccording to the results obtained in this study, we analyzed its main mechanism in two points: First, the \"three-joint complex\" formed by the IVD and the facet joints on both sides-This special structure plays a very important role in maintaining and stabilizing the balance and coordination of lumbar spine activities\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. Abnormalities in any one part will affect the other two parts and thus the whole. The lumbar IVD of the patients in this study group all have different degrees of degeneration. The earliest due to the IVDD changes, the intervertebral space is narrowed, the height of the IVD is lost, and the lumbar vertebral is unstable, which further causes local load bearing on the facet joints\u003csup\u003e[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/sup\u003e. As a result, the stress-increasing site are more prone to bone hyperplasia, and the stress-reduced site is more prone to osteoporosis, accompanied by the existence of corresponding soft tissue repair and reconstruction, and finally the sagittal change of the facet joints\u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/sup\u003e. Second, there are different biomechanical factors in L4/5 and L5/S1 IVDD. The degeneration of the L4/5 IVD is mainly related to the way of rotational movement, and the morphological basis of the L4/5 facet joint is the curved articular surface\u003csup\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e. The degeneration of the L5/S1 IVD is mainly related to the stability of the spine and the gravitational load. The L5/S1 facet joint typically has a flatter and more coronally oriented articular surface compared to upper lumbar levels [23].. In the lumbar spine, facet joints are more sagittally oriented in higher segments (e.g., L4-L5) compared to lower segments (e.g., L5-S1). This anatomical variation reduces their ability to resist shear forces, resulting in stress concentration during load transmission. Consequently, the L5/S1 facet joints experience increased gravitational and shear loads, which may impair their function over time. Progressive facet degeneration and ligamentous instability can then promote abnormal spinal motion, further accelerating IVDD\u003csup\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThis study has several limitations: First, as a retrospective study, it is subject to inherent biases associated with this design. Second, potential confounding factors such as occupation, smoking history, age, and body mass index were not accounted for in analyzing the relationship between LFJA and IVDD, which may affect the observed associations\u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/sup\u003e. Finally, while this study provides important insights into the association between facet joint parameters and IVDD at L3/4, L4/5, and L5/S1 levels, future research should include more intervertebral segments and additional influencing factors for more comprehensive analysis.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn this study, we analyzed Pfirrmann degeneration grades for three intervertebral discs (L3/4, L4/5, and L5/S1) using MRI and measured the lumbar facet joint angles (LFJA) of corresponding vertebral segments. Our findings confirm a significant association between LFJA and IVDD.\u003c/p\u003e\u003cp\u003eThe study demonstrates a strong negative correlation between IVDD severity and the degree of lumbar facet joint sagittalization. This relationship was particularly evident in the lower lumbar vertebrae (L4/5 and L5/S1). These findings provide valuable theoretical insights that may inform clinical understanding of lumbar IVDD pathogenesis and guide treatment strategies.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eBMI\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBody mass index\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eLBP\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eLow back pain\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eLFJA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eLumbar facet joint angle\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eIVD\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eIntervertebral disc\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eIVDD\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eIntervertebral disc degeneration\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eMRI\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMagnetic resonance imaging\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eFOV\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eField of view\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eT2Wis\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eT2-weighted images\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eTE\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eEcho time\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eTR\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eRepetition time.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported by the Science and Technology Development Fund of Nanjing Medical University (No. NMUB20220153), and the Youth Exploration Project Fund of the Fourth Affiliated Hospital of Nanjing Medical University (No. 23YJRC27)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data supporting our findings can be found in the article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLTH designed and performed the study, and wrote and edited the manuscript. ZPS revised the manuscript, conceived and designed the study. JC analyzed and interpreted the data. CZ revised the manuscript. LB and LQ assisted with data presentation and drafting of the manuscript. BZ and JC conceived and designed the study, and assisted with the research, drafting, and revision of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclarations: Competing interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experimental protocol was established according to the ethical guidelines of the Helsinki Declaration and was approved by the Human Ethics Committee of Fourth Affiliated Hospital of Nanjing Medical University. Written informed consent was obtained from all participants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors have read this article and agree to publish.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eChepurin, D. et al. Bony stress in the lumbar spine is associated with intervertebral disc degeneration and low back pain: a retrospective case-control MRI study of patients under 25 years of age. \u003cem\u003eEur. Spine J.\u003c/em\u003e \u003cb\u003e28\u003c/b\u003e (11), 2470\u0026ndash;2477 (2019).\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFarmer, C. et al. Consumer understanding of terms used in imaging reports requested for low back pain: a cross-sectional survey. \u003cem\u003eBMJ Open.\u003c/em\u003e \u003cb\u003e11\u003c/b\u003e (9), e049938 (2021).\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLv, B. et al. 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Phys.\u003c/em\u003e \u003cb\u003e102\u003c/b\u003e, 103779 (2022).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"lumbar intervertebral disc, intervertebral disc degeneration, lumbar facet joint angle, facet joint sagittalization","lastPublishedDoi":"10.21203/rs.3.rs-7009092/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7009092/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eTo investigate the correlation between sagittalization of lumbar facet joints and lumbar intervertebral disc degeneration (IVDD).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eSeventy-five patients with low back pain and forty healthy volunteers (control) underwent standard MRI protocols. The basic information of all patients, including age, gender, body mass index, was collected, and the lumbar facet joint angle (LFJA) was measured on lumbar magnetic resonance imaging (MRI), and the lumbar IVDD was assessed by Pfirrmann grading. All data were analyzed statistically.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eCompared with the control group, the LFJA of L3/4, L4/5 and L5/S1 in the patient group were significantly decreased, and there was a statistical difference (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The lower the segment, the more significant the sagittalization of the facet joints (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). In the patient group, there was a statistically significant difference in the LFJA between the Pfirrmann grades of lumbar IVDD, and there was a strong negative correlation (ρ=-0.736, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eWith the increase of the sagittal degree of LFJA, the IVDD also increases significantly, and this relationship has a strong negative correlation. It is suggested that the sagittalization of facet joints may be an important pathogenic factor of lumbar IVDD.\u003c/p\u003e","manuscriptTitle":"Association Between Facet Joint Sagittalization and Intervertebral Disc Degeneration: A Retrospective Radiological Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-10 12:48:44","doi":"10.21203/rs.3.rs-7009092/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"3a93e4e1-515a-42b2-a9e8-5833836a1875","owner":[],"postedDate":"July 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":51224886,"name":"Health sciences/Anatomy"},{"id":51224887,"name":"Health sciences/Diseases"},{"id":51224888,"name":"Health sciences/Health care"},{"id":51224889,"name":"Health sciences/Medical research"}],"tags":[],"updatedAt":"2025-07-31T13:54:07+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-10 12:48:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7009092","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7009092","identity":"rs-7009092","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}