The Effect of Segmental Hyper-Mobility on Development of Cervical Disc Degeneration: a Retrospective Study

The Effect of Segmental Hyper-Mobility on Development of Cervical Disc Degeneration: a Retrospective Study | 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 Research Article The Effect of Segmental Hyper-Mobility on Development of Cervical Disc Degeneration: a Retrospective Study Chang-Hyung Lee, Sang-Hee Park, Hoyoung Cho, Youn-Young Lee, Hwagyeong Lee This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8277180/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 The aging factor, which appears to be the result of chronic repetitive movement, has been identified as a crucial factor of spinal degenerative joint disease (DJD). However, there has been no study to evaluate the relationship between the amount of movement and the prevalence of DJD. Thus, the purpose of our study was to investigate the relationship between segmental mobility of the cervical spine and the prevalence of DJD, and to compare it with other known etiologic factors of DJD. Methods A retrospective analysis of cervical radiographs (neutral, flexion, and extension views) and MRI scans of 101 patients with neck pain (28 male, 72 female; mean age 51.51 ± 6.78 years) was conducted. Amount of segmental range of motion (ROM) from C2/3 to C6/7 was measured. Patients were categorized into three groups: No DJD, Single DJD, and Multiple DJD. To assess the association between segmental mobility angle, demographic factors and multiple DJD progression, one-way ANOVA and multiple linear regression analyses were performed. Results The middle cervical region exhibited the most extensive range of motion, exclusively the C4/5 segment demonstrating the highest mobility (12.70° ± 5.00°). The most prevalent site for DJD was C6/7 (75, 74.3%). Comparison of the groups by the ANOVA, distinct hyper-mobility pattern was the key factor : while the No-DJD group maintained stable motion at C4/5 (10.20°), both the single and multiple DJD groups exhibited a significant increase in hyper-mobility at this segment (p = 0.034). Multiple regression analysis adjusted for confounding factors revealed that C4/5 mobility was a significant independent predictor of multiple DJD progression (ß = 0.342, p = 0.003), whereas age, gender, and BMI did not show a significant effect. Conclusion The middle cervical segment (C4/5) showed the greatest range of motion and correlated with the highest prevalence of multiple DJD. Specifically, segmental hyper-mobility at the C4/5 level, characterized by distinct focal hyper-mobility, is strongly associated with the multiple progression of cervical DJD with this correlation outweighing the effect of age. Cervical Vertebrae Intervertebral Disc Degeneration Joint Instability Biomechanics Range of Motion Figures Figure 1 Figure 2 Introduction Cervical degenerative joint disease (DJD) is a prevalent musculoskeletal disorder and a major cause of neck pain, affecting a significant portion of the population and imposing a substantial economic burden ( 1 – 4 ). The condition involves progressive degeneration of the intervertebral discs, including the annulus fibrosus and nucleus pulposus, as well as the facet joints ( 5 , 6 ). The etiology of DJD is multifactorial, with established risk factors including age, body mass index (BMI), smoking, and metabolic conditions such as diabetes mellitus ( 7 – 10 ). Among these factors, age is the most crucial factor of cervical DJD ( 11 ). The aging factor, which appears to be the result of chronic repetitive movement, has been identified as a crucial factor of spinal degenerative joint disease (DJD). In this sense, Mechanical stress from movement patterns is a critical contributor to cause DJD ( 12 ). The intervertebral disc, which transmits stress between adjacent vertebrae, is highly sensitive to mechanical loads ( 13 ). Postures such as prolonged neck flexion or forward head posture (FHP), along with repetitive occupational movements, can accelerate degenerative changes ( 14 , 15 ). Unlike the lumbar spine, the cervical spine is less exposed to heavy weight-bearing but is subjected to static loads, vibrations, and extreme postures ( 16 ). In vivo studies have shown that disc deformation during maximal neck flexion and extension can exceed 70% of the disc height, varying significantly across segmental levels ( 17 , 18 ). Repetitive, abnormal movements, such as those seen in cervical dystonia and cerebral palsy, have been linked to an unusually high incidence of severe degenerative changes, further highlighting the role of kinematics in the pathology of DJD ( 19 , 20 ). Previous studies have reported that degenerative changes occur most frequently in the middle cervical region, specifically at the C4/5, C5/6, and C6/7 levels, while the upper and lower cervical regions are less commonly affected ( 21 – 23 ). This prevalence pattern has been attributed to movement, but the underlying biomechanical explanation remains unclear. Theoretically, in postures like FHP or cervical kyphosis, the upper and lower cervical segments are relatively fixed to the skull and thoracic spine, respectively ( 24 ). To achieve functional mobility, the middle cervical region must compensate with increased motion, leading to relative hyper-mobility. This segmental hyper-mobility is hypothesized to concentrate mechanical stress and accelerate disc degeneration in the middle segments ( 25 , 26 ). However, there is a lack of research directly correlating segmental movement ratios with the prevalence of DJD. Therefore, this study aimed to assess the movement of the upper, middle, and lower cervical segments and to investigate the correlation between segmental mobility and the presence of DJD. We hypothesized that hyper-mobility in the middle cervical region is a significant factor in the development of cervical DJD which is the key mechanism of aging process. Methods Study Design and Subjects This retrospective study was conducted after receiving approval from the Pusan National University Yangsan Hospital Institutional Review Board (IRB No: 05-2021-210). The requirement for informed consent was waived by the IRB. We reviewed the electronic medical records of patients aged 20 to 65 who presented with neck pain and underwent both cervical plain radiography and magnetic resonance imaging (MRI) between January 2020 and December 2024 at our department. Exclusion criteria were as follows: ( 1 ) age younger than 20 or older than 65 years; ( 2 ) previous cervical spinal surgery; ( 3 ) radiographic evidence of ankylosing spondylitis, congenital spinal anomalies, tumors, or vertebral fractures; ( 4 ) known movement disorders (e.g., Cerebral Palsy, dystonia); ( 5 ) severe cervical kyphosis (reverse lordosis); or ( 6 ) advanced, multi-level disc degeneration (Pfirrmann Grade V or complete adhesion) ( 7 ). Radiographic Measurements Cervical spine radiographs were obtained using an X-ray system (Innovision-Sh 3D; DK Healthcare Company, Korea) ( 27 ). All subjects were positioned standing, with shoulders relaxed. Lateral images were taken in neutral, maximal voluntary flexion, and maximal voluntary extension positions (Fig. 1 ). Images were analyzed using INFINITT PACS M6 software (INFINITT Healthcare Corp., Seoul, Korea) ( 28 ). The intervertebral disc angle for each segment (C2/3 to C6/7) was defined as the Cobb angle between the inferior endplate of the superior vertebral body and the superior endplate of the inferior vertebral body ( 29 ). The range of motion (ROM) for each segment was calculated as the difference between the flexion and extension angles. To ensure reliability, all angles were measured independently by two experienced physicians, and the mean value was used for analysis. MRI Analysis Cervical disc degeneration was evaluated on T2-weighted sagittal MRI scans by an experienced physician blinded to the radiographic findings. The degree of degeneration for each disc from C2/3 to C6/7 was graded using the Pfirrmann classification ( 30 ). Disc degeneration is classified grades: Grade 0 (no degeneration), Grade I (mild degeneration), Grade II (moderate degeneration), and Grade III (severe degeneration). Grade I indicates low intensity change or structural change of the nucleus pulposus; Grade II indicates disc bulge or herniation with degeneration of the annulus fibrosus; and Grade III indicates further degeneration with disc height decrease of more than 25% ( 31 ). For the purpose of regression analysis, DJD severity was categorized based on the number of degenerated (Pfirrmann Grade ≥ I) discs: 0 (No DJD): No discs with Pfirrmann Grade ≥ I., 1 (Mild DJD): One or two discs with Pfirrmann Grade ≥ I., 2 (Severe DJD): Three or more discs with Pfirrmann Grade ≥ I. Statistical Analysis Statistical Analysis All statistical analyses were performed using SPSS version 27.0 (IBM Corp., Armonk, NY, USA). Descriptive statistics (mean ± standard deviation for continuous variables; frequency and percentage for categorical variables) were used to summarize the demographic characteristics. The normality of distribution for all continuous variables was assessed using the Kolmogorov-Smirnov test. A one-way analysis of variance (ANOVA) was used to compare the segmental ROM among the three groups (No DJD, Single DJD, and Multiple DJD). Tukey’s Honest Significant Difference (HSD) test was performed for post-hoc comparisons. A multiple linear regression analysis was conducted to determine the independent effect of C4/5 mobility on the multiple progression of DJD (coded 0, 1, 2), after adjusting for potential confounding factors including age, gender, and body mass index (BMI). The level of statistical significance was set at p < 0.05. Results Demographic and Clinical Characteristics A total of 181 patient charts were initially reviewed. After applying the exclusion criteria, 101 patients (28 male, 72 female) were included in the final analysis. The mean age of the subjects was 51.51 ± 6.78 years. The mean height, weight, and BMI were 163.23 ± 8.73 cm, 62.95 ± 11.62 kg, and 23.57 ± 3.60 kg/m², respectively. Among the subjects, 78 (77.2%) had evidence of DJD on MRI. The demographic characteristics are detailed in Table 1 . Table 1 Demographic characteristics of subjects (N = 101) Variables Mean ± SD age (yrs) 51.51 ± 6.78 gender Male 28 (27.7%) Female 72 (71.3%) height (cm) 163.23 ± 8.73 weight (kg) 62.95 ± 11.62 BMI (kg/m 2 ) 23.57 ± 3.6 medical conditions DM 13 (12.9%) NON-DJD (number) 22 (21.8%) DJD 78 (77.2%) (number) Location of the DJD C2/3 54 (53.5%) C3/4 66 (65.3%) C4/5 74 (73.3%) C5/6 72 (71.3%) C6/7 75 (74.3%) C7/T1 62 (61.4%) Values are presented as mean ± SD or n (%); BMI, Body Mass Index; DJD, Degenerative Joint Disease. Amount of Segmental Range of Motion The segments C3/4, C4/5, and C5/6 exhibited greater mobility compared to the uppermost (C2/3) and lowest (C6/7) segments in both groups. The C4/5 segment was identified as the most mobile (12.70° ± 5.00°), and the C2/3 segment was the least mobile (6.31° ± 3.51°). Table 2 presents the segmental ROM. Table 2 Changes of intervertebral disc angle between C2, 3, 4, 5, 6, and 7 segment in response to cervical movement. variables Neutral Flexion Extension Extension – Flexion angle (°) (°) (°) (°) Upper cervical region (C2/3) 0.53 ± 4.17 2.56 ± 4.51 3.31 ± 4.33 6.31 ± 3.51 Middle cervical region C3/4 0.29 ± 4.82 5.02 ± 4.00 5.75 ± 4.77 10.91 ± 4.46 C4/5 0.24 ± 4.29 6.47 ± 4.04 6.14 ± 5.13 12.70 ± 5.00 C5/6 2.84 ± 4.98 3.23 ± 4.77 7.93 ± 4.84 11.30 ± 5.75 Lower cervical region (C6/7) 6.44 ± 4.21 0.92 ± 4.42 8.04 ± 4.73 7.61 ± 4.82 DJD, Degenerative Joint Disease; SD, Standard Deviation; df, degrees of freedom. One-way ANOVA revealed that segmental mobility at the C4/5 level differed significantly among the three groups (F = 3.497, p = 0.034). While the No-DJD group exhibited relatively stable or lower mobility at C4/5 (10.20° ± 5.00°), both the Single DJD (13.50° ± 5.46°) and Multiple DJD (13.35° ± 4.75°) groups demonstrated a distinct hyper-mobility at this segment. In contrast, no significant differences were observed in the upper (C2/3) or lower (C6/7) cervical segments (p > 0.05). Detailed comparisons are shown in Table 3 and Fig. 2 . Table 3 Comparison of segmental range of motion (ROM) among the three groups Segment No DJD (group 1) Single DJD (group 2) Multiple DJD (group 3) F P-value (n = 21) (n = 11) (n = 68) C2/3 5.20 ± 3.76 7.43 ± 4.79 6.47 ± 3.16 1.708 0.187 C3/4 11.81 ± 3.77 11.15 ± 4.17 10.60 ± 4.71 0.596 0.553 C4/5 10.20 ± 5.00 13.50 ± 5.46 13.35 ± 4.75 3.497 0.034* C5/6 11.23 ± 5.14 10.60 ± 5.10 11.43 ± 6.08 0.1 0.905 C6/7 7.01 ± 5.09 7.20 ± 3.71 7.86 ± 4.93 0.289 0.75 Values are presented as Mean ± Standard Deviation (°), DJD: Degenerative Joint Disease, *p < 0.05. Association Between Structural Factors, Mobility and the Prevalence of DJD To control for potential confounding factors, a multiple linear regression analysis was performed including age, gender, and BMI. Even after adjusting for these variables, C4/5 segmental mobility remained the only statistically significant predictor of multiple DJD progression (ß = 0.342, p = 0.003). Other factors, including age (p = 0.421), gender (p = 0.222), and BMI (p = 0.247), did not show a significant association with the extent of disc degeneration. These results are summarized in Table 4 . Table 4 Multiple regression analysis predicting multiple DJD progression adjusting for confounders Independent variables Dependent variables Standardized ß t P-value DJD (Constant) − .108 .914 Structural Factors Age .092 .810 .421 Gender − .137 -1.234 .222 BMI .132 1.167 .247 Mobility of C4/5 .342 3.048 .003** Dependent Variable: multiple DJD progression. R² = 0.158. **p < 0.01. Association between Segmental Mobility and multiple DJD progression Linear regression analysis revealed distinct kinematic patterns across the cervical regions (Table 4 ). The middle cervical segment (C4/5) demonstrated a statistically significant positive association with the multiple DJD (ß = 0.357, p = 0.021). In contrast, the upper (C2/3) and lower (C6/7) segments did not reach statistical significance, indicating that kinematic instability specifically in the middle cervical spine is a key contributor to the degenerative process. Table 5 Linear regression analysis of segmental mobility and multiple DJD progression Cervical Region Segment Standardized ß P-value R² value Upper C2/3 .242 .055 .003 Middle C4/5 .357 .021* .027 Lower C6/7 .216 .148 .004 *p < 0.05. Discussion This study investigated the relationship between regional and segmental mobility and the prevalence of cervical DJD, in succession of elucidating the key mechanism of aging which is the crucial factor of DJD. Our principal finding is that hyper-mobility of the middle cervical spine, specifically at the C4/5 segment, is significantly associated with the multiple DJD progression, which signifies that the main mechanism of aging factor is exposure to chronic repetitive movement. This supports the hypothesis that excessive movement causes segmental stress thus leads critical cervical pathogenesis of DJD. A key finding of this study is the distinct alteration in excessive movement at middle cervical region, especially at C4/5 intervertebral segments. In addition, middle segment and C4/5 segments showed positive correlation with prevalence of DJD. As illustrated in Fig. 2 , the control group (No DJD) demonstrated a gradual curve, characterized by a controlled flat pattern (not exceeding range of motion compare to the adjacent segment). This suggests that, in the healthy cervical spine, the C4/5 segment is functionally stabilized by the coordinated movement of neighboring segments (C3/4 and C5/6), preventing stress concentration. Conversely, DJD groups exhibit an excessive movement pattern at C4/5, characterized by focal hyper-mobility due to a failure of controlled motion. This concentration of repetitive mechanical load suggests that segmental instability is a primary driving factor disrupting physiological stress distribution, consistent with previous biomechanical studies ( 14 , 32 ). The finding that C4/5 hyper-mobility, the key mechanism of aging process, was the significant predictor in our regression model is particularly noteworthy. While age is an undeniable factor in the gradual dehydration and structural weakening of intervertebral discs ( 8 ), our study suggests that in a given condition which is mild symptom and middle-aged population (20–65), abnormal segmental movement appears to be a more immediate and potent contributor to clinically relevant degeneration in addition to aging process. This implies that once a certain age threshold is reached, an individual's unique movement patterns and spinal alignment may play a additional dominant role in determining the location and progress of multiple DJD. Segmental hyper-mobility in the middle cervical region (C4/5) is hypothesized to act as a primary independent contributor to multiple DJD by exerting mechanical stress on adjacent levels and accelerating the degenerative cascade. The clinical implication of our finding is meaningful. It is suggested that interventions should not only address pain but also focus on correcting underlying movement pattern abnormality. According to the previous reports, which shows that physical therapy programs aimed at restoring a balanced movement pattern at all cervical segments, rather than allowing for excessive segmental hyper-mobility, could be crucial in preventing the progression of DJD ( 6 ). Furthermore, the use of dynamic flexion-extension radiographs, which are not always standard practice, may be valuable for identifying patients at risk of accelerated degeneration due to segmental instability, as these can reveal kinematic abnormalities not visible on static images ( 33 ). This study has several limitations. First, its retrospective, cross-sectional design prevents the establishment of causality; we can only report an association between hyper-mobility and DJD. A prospective study following a young, asymptomatic cohort would be needed to confirm if hyper-mobility precedes and causes degeneration. Second, we only analyzed motion in the sagittal plane (flexion-extension). Rotational and lateral bending movements, particularly at the C0/1 and C1/2 levels, were not assessed but also can contribute to cervical kinematics. Third, our exclusion of patients with severe, advanced degeneration (Pfirrmann Grade V) means our findings may be limited to those with mild-to-moderate DJD. In advanced stages, segments often become stiff and hypomobile, representing a different phase of the degenerative process. Finally, although we identified a distinct hyper-mobility at the C4/5 segment, this study did not establish a specific quantitative cut-off value for hyper-mobility that predicts the onset of DJD. Future studies with larger cohorts are needed to determine a diagnostic threshold for kinematic instability. Conclusion This study demonstrates that hyper-mobility of the middle cervical spine region, particularly at the C4/5 segment, is a significant independent factor associated with the multiple progression of cervical DJD. Notably, this regional and segmental hyper-mobility appears to be the key mechanism of aging process which accelerates the multiple DJD progression. Declarations Ethics approval and consent to participate: This study was approved by the Pusan National University Yangsan Hospital Institutional Review Board (IRB No: 05-2021-210). The requirement for informed consent was waived by the IRB due to the retrospective nature of the study. Consent for publication: Not applicable. Competing interests: The authors declare that they have no competing interests. Funding: This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. 2022R1A5A8023404). Author Contribution C.H.L. designed the study. H.G.L., S.H.P. and H.C. performed data collection and radiographic measurements. Y.Y.L. conducted statistical analysis. H.G.L. drafted the manuscript. C.H.L. supervised the study and revised the manuscript. All authors reviewed the manuscript. Acknowledgements: Not applicable. Data Availability The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request. References Fu Z, Xie Y, Li P, Gao M, Chen J, Ning N. Assessing multidisciplinary follow-up pattern efficiency and cost in follow-up care for patients in cervical spondylosis surgery: a non-randomized controlled study. Front Med. 2024;11:1354483. 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12:27:43","extension":"html","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":139383,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8277180/v1/022fc3ef8a18f8a1a7a8ee0e.html"},{"id":98779779,"identity":"8b61412d-8993-4894-a71c-2f70f388cac3","added_by":"auto","created_at":"2025-12-22 12:30:44","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":431933,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRadiographic measurement of cervical segmental range of motion (ROM).\u003c/strong\u003e \u003cstrong\u003e(A)\u003c/strong\u003e Lateral cervical radiograph in the neutral position. \u003cstrong\u003e(B)\u003c/strong\u003e \u003cstrong\u003eExtension\u003c/strong\u003e view showing the measurement of intervertebral angles using the Cobb angle method. Lines are drawn along the inferior endplate of the superior vertebra and the superior endplate of the inferior vertebra to measure segmental angles from C2/3 to C6/7 (colored lines). \u003cstrong\u003e(C)\u003c/strong\u003e \u003cstrong\u003eFlexion\u003c/strong\u003eview. The segmental ROM was calculated as the difference between the extension and flexion angles for each segment.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8277180/v1/48e94ffe7e6e8280904337cd.jpg"},{"id":98777607,"identity":"2109619d-0503-4e8d-ad56-59a4ebaf7b3a","added_by":"auto","created_at":"2025-12-22 12:28:10","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":144676,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparison of segmental range of motion (ROM) patterns across cervical segments (C2/3–C6/7) among the three groups.\u003c/strong\u003e The ‘No DJD’ group (Group 1, grey line) exhibits a relatively stable ROM pattern with flat, no-excessive mobility, at C4/5. In contrast, both the ‘Single DJD’ (Group 2, blue line) and ‘Multiple DJD’ (Group 3, red line) groups demonstrate a distinct hyper-mobility (arrow) at the C4/5 segment, indicating segmental hyper-mobility.\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8277180/v1/7581a9a217281caf8d790640.jpg"},{"id":98794834,"identity":"5b089da7-ca85-47f6-b22b-842a2ce37d8e","added_by":"auto","created_at":"2025-12-22 12:51:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1536710,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8277180/v1/cc1fb6b4-7aba-4604-8f5e-57603f615429.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The Effect of Segmental Hyper-Mobility on Development of Cervical Disc Degeneration: a Retrospective Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCervical degenerative joint disease (DJD) is a prevalent musculoskeletal disorder and a major cause of neck pain, affecting a significant portion of the population and imposing a substantial economic burden (\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). The condition involves progressive degeneration of the intervertebral discs, including the annulus fibrosus and nucleus pulposus, as well as the facet joints (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). The etiology of DJD is multifactorial, with established risk factors including age, body mass index (BMI), smoking, and metabolic conditions such as diabetes mellitus (\u003cspan additionalcitationids=\"CR8 CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAmong these factors, age is the most crucial factor of cervical DJD (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). The aging factor, which appears to be the result of chronic repetitive movement, has been identified as a crucial factor of spinal degenerative joint disease (DJD).\u003c/p\u003e \u003cp\u003eIn this sense, Mechanical stress from movement patterns is a critical contributor to cause DJD (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). The intervertebral disc, which transmits stress between adjacent vertebrae, is highly sensitive to mechanical loads (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). Postures such as prolonged neck flexion or forward head posture (FHP), along with repetitive occupational movements, can accelerate degenerative changes (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). Unlike the lumbar spine, the cervical spine is less exposed to heavy weight-bearing but is subjected to static loads, vibrations, and extreme postures (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). In vivo studies have shown that disc deformation during maximal neck flexion and extension can exceed 70% of the disc height, varying significantly across segmental levels (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). Repetitive, abnormal movements, such as those seen in cervical dystonia and cerebral palsy, have been linked to an unusually high incidence of severe degenerative changes, further highlighting the role of kinematics in the pathology of DJD (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e).\u003c/p\u003e \u003cp\u003ePrevious studies have reported that degenerative changes occur most frequently in the middle cervical region, specifically at the C4/5, C5/6, and C6/7 levels, while the upper and lower cervical regions are less commonly affected (\u003cspan additionalcitationids=\"CR22\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). This prevalence pattern has been attributed to movement, but the underlying biomechanical explanation remains unclear. Theoretically, in postures like FHP or cervical kyphosis, the upper and lower cervical segments are relatively fixed to the skull and thoracic spine, respectively (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e). To achieve functional mobility, the middle cervical region must compensate with increased motion, leading to relative hyper-mobility. This segmental hyper-mobility is hypothesized to concentrate mechanical stress and accelerate disc degeneration in the middle segments (\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eHowever, there is a lack of research directly correlating segmental movement ratios with the prevalence of DJD. Therefore, this study aimed to assess the movement of the upper, middle, and lower cervical segments and to investigate the correlation between segmental mobility and the presence of DJD. We hypothesized that hyper-mobility in the middle cervical region is a significant factor in the development of cervical DJD which is the key mechanism of aging process.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Design and Subjects\u003c/h2\u003e \u003cp\u003e This retrospective study was conducted after receiving approval from the Pusan National University Yangsan Hospital Institutional Review Board (IRB No: 05-2021-210). The requirement for informed consent was waived by the IRB. We reviewed the electronic medical records of patients aged 20 to 65 who presented with neck pain and underwent both cervical plain radiography and magnetic resonance imaging (MRI) between January 2020 and December 2024 at our department.\u003c/p\u003e \u003cp\u003eExclusion criteria were as follows: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) age younger than 20 or older than 65 years; (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) previous cervical spinal surgery; (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) radiographic evidence of ankylosing spondylitis, congenital spinal anomalies, tumors, or vertebral fractures; (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e) known movement disorders (e.g., Cerebral Palsy, dystonia); (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e) severe cervical kyphosis (reverse lordosis); or (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e) advanced, multi-level disc degeneration (Pfirrmann Grade V or complete adhesion) (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eRadiographic Measurements\u003c/h3\u003e\n\u003cp\u003eCervical spine radiographs were obtained using an X-ray system (Innovision-Sh 3D; DK Healthcare Company, Korea) (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e). All subjects were positioned standing, with shoulders relaxed. Lateral images were taken in neutral, maximal voluntary flexion, and maximal voluntary extension positions (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Images were analyzed using INFINITT PACS M6 software (INFINITT Healthcare Corp., Seoul, Korea) (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe intervertebral disc angle for each segment (C2/3 to C6/7) was defined as the Cobb angle between the inferior endplate of the superior vertebral body and the superior endplate of the inferior vertebral body (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e). The range of motion (ROM) for each segment was calculated as the difference between the flexion and extension angles. To ensure reliability, all angles were measured independently by two experienced physicians, and the mean value was used for analysis.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eMRI Analysis\u003c/h3\u003e\n\u003cp\u003eCervical disc degeneration was evaluated on T2-weighted sagittal MRI scans by an experienced physician blinded to the radiographic findings. The degree of degeneration for each disc from C2/3 to C6/7 was graded using the Pfirrmann classification (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e). Disc degeneration is classified grades: Grade 0 (no degeneration), Grade I (mild degeneration), Grade II (moderate degeneration), and Grade III (severe degeneration). Grade I indicates low intensity change or structural change of the nucleus pulposus; Grade II indicates disc bulge or herniation with degeneration of the annulus fibrosus; and Grade III indicates further degeneration with disc height decrease of more than 25% (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFor the purpose of regression analysis, DJD severity was categorized based on the number of degenerated (Pfirrmann Grade\u0026thinsp;\u0026ge;\u0026thinsp;I) discs: 0 (No DJD): No discs with Pfirrmann Grade\u0026thinsp;\u0026ge;\u0026thinsp;I., 1 (Mild DJD): One or two discs with Pfirrmann Grade\u0026thinsp;\u0026ge;\u0026thinsp;I., 2 (Severe DJD): Three or more discs with Pfirrmann Grade\u0026thinsp;\u0026ge;\u0026thinsp;I.\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eStatistical Analysis All statistical analyses were performed using SPSS version 27.0 (IBM Corp., Armonk, NY, USA). Descriptive statistics (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation for continuous variables; frequency and percentage for categorical variables) were used to summarize the demographic characteristics. The normality of distribution for all continuous variables was assessed using the Kolmogorov-Smirnov test. A one-way analysis of variance (ANOVA) was used to compare the segmental ROM among the three groups (No DJD, Single DJD, and Multiple DJD). Tukey\u0026rsquo;s Honest Significant Difference (HSD) test was performed for post-hoc comparisons. A multiple linear regression analysis was conducted to determine the independent effect of C4/5 mobility on the multiple progression of DJD (coded 0, 1, 2), after adjusting for potential confounding factors including age, gender, and body mass index (BMI). The level of statistical significance was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eDemographic and Clinical Characteristics\u003c/h2\u003e \u003cp\u003eA total of 181 patient charts were initially reviewed. After applying the exclusion criteria, 101 patients (28 male, 72 female) were included in the final analysis. The mean age of the subjects was 51.51\u0026thinsp;\u0026plusmn;\u0026thinsp;6.78 years. The mean height, weight, and BMI were 163.23\u0026thinsp;\u0026plusmn;\u0026thinsp;8.73 cm, 62.95\u0026thinsp;\u0026plusmn;\u0026thinsp;11.62 kg, and 23.57\u0026thinsp;\u0026plusmn;\u0026thinsp;3.60 kg/m\u0026sup2;, respectively. Among the subjects, 78 (77.2%) had evidence of DJD on MRI. The demographic characteristics are detailed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\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\u003eDemographic characteristics of subjects (N\u0026thinsp;=\u0026thinsp;101)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\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\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eage (yrs)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e51.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.78\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003egender\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e28 (27.7%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e72 (71.3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eheight (cm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e163.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8.73\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eweight (kg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e62.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e11.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003emedical conditions\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"9\" rowspan=\"10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e13 (12.9%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNON-DJD (number)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e22 (21.8%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDJD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" morerows=\"1\" nameend=\"c6\" namest=\"c4\" rowspan=\"2\"\u003e \u003cp\u003e78 (77.2%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e(number)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003eLocation of the DJD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC2/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e54 (53.5%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC3/4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e66 (65.3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC4/5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e74 (73.3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC5/6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e72 (71.3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC6/7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e75 (74.3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC7/T1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e62 (61.4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003eValues are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD or n (%); BMI, Body Mass Index; DJD, Degenerative Joint Disease.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAmount of Segmental Range of Motion\u003c/h3\u003e\n\u003cp\u003eThe segments C3/4, C4/5, and C5/6 exhibited greater mobility compared to the uppermost (C2/3) and lowest (C6/7) segments in both groups. The C4/5 segment was identified as the most mobile (12.70\u0026deg; \u0026plusmn; 5.00\u0026deg;), and the C2/3 segment was the least mobile (6.31\u0026deg; \u0026plusmn; 3.51\u0026deg;). Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents the segmental ROM.\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\u003eChanges of intervertebral disc angle between C2, 3, 4, 5, 6, and 7 segment in response to cervical movement.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"14\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" morerows=\"1\" nameend=\"c2\" namest=\"c1\" rowspan=\"2\"\u003e \u003cp\u003evariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e \u003cp\u003eNeutral\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e \u003cp\u003eFlexion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c11\" namest=\"c9\"\u003e \u003cp\u003eExtension\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c14\" namest=\"c12\"\u003e \u003cp\u003eExtension \u0026ndash; Flexion angle\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e \u003cp\u003e(\u0026deg;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e \u003cp\u003e(\u0026deg;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c11\" namest=\"c9\"\u003e \u003cp\u003e(\u0026deg;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c14\" namest=\"c12\"\u003e \u003cp\u003e(\u0026deg;)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eUpper cervical region (C2/3)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e4.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e6.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e3.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003eMiddle cervical region\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC3/4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e5.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e4.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e10.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e4.46\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC4/5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e6.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e5.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e12.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e5.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC5/6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e7.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e4.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e11.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e5.75\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLower cervical region (C6/7)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e8.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e4.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e4.82\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"14\" nameend=\"c14\" namest=\"c1\"\u003e \u003cp\u003eDJD, Degenerative Joint Disease; SD, Standard Deviation; df, degrees of freedom.\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\u003eOne-way ANOVA revealed that segmental mobility at the C4/5 level differed significantly among the three groups (F\u0026thinsp;=\u0026thinsp;3.497, p\u0026thinsp;=\u0026thinsp;0.034). While the No-DJD group exhibited relatively stable or lower mobility at C4/5 (10.20\u0026deg; \u0026plusmn; 5.00\u0026deg;), both the Single DJD (13.50\u0026deg; \u0026plusmn; 5.46\u0026deg;) and Multiple DJD (13.35\u0026deg; \u0026plusmn; 4.75\u0026deg;) groups demonstrated a distinct hyper-mobility at this segment. In contrast, no significant differences were observed in the upper (C2/3) or lower (C6/7) cervical segments (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Detailed comparisons are shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\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\u003eComparison of segmental range of motion (ROM) among the three groups\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"12\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSegment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eNo DJD (group 1)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c7\" namest=\"c5\"\u003e \u003cp\u003eSingle DJD (group 2)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003eMultiple DJD (group 3)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;21)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c7\" namest=\"c5\"\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;68)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC2/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e6.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e3.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1.708\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.187\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC3/4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e11.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e10.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e4.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.596\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.553\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC4/5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e10.20\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e\u0026plusmn;\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e5.00\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e13.50\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026plusmn;\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e5.46\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e13.35\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e\u0026plusmn;\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cb\u003e4.75\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e3.497\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e\u003cb\u003e0.034*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC5/6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e6.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.905\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC6/7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u0026plusmn;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e4.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.289\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.75\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"12\"\u003eValues are presented as Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;Standard Deviation (\u0026deg;), DJD: Degenerative Joint Disease, *p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eAssociation Between Structural Factors, Mobility and the Prevalence of DJD\u003c/h3\u003e\n\u003cp\u003eTo control for potential confounding factors, a multiple linear regression analysis was performed including age, gender, and BMI. Even after adjusting for these variables, C4/5 segmental mobility remained the only statistically significant predictor of multiple DJD progression (\u0026szlig; = 0.342, p\u0026thinsp;=\u0026thinsp;0.003). Other factors, including age (p\u0026thinsp;=\u0026thinsp;0.421), gender (p\u0026thinsp;=\u0026thinsp;0.222), and BMI (p\u0026thinsp;=\u0026thinsp;0.247), did not show a significant association with the extent of disc degeneration. These results are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMultiple regression analysis predicting multiple DJD progression adjusting for confounders\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIndependent variables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eDependent variables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStandardized \u0026szlig;\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003et\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003eDJD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e(Constant)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026minus;\u0026thinsp;.108\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e.914\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eStructural Factors\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.092\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.810\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e.421\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026minus;\u0026thinsp;.137\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-1.234\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e.222\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBMI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.132\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.167\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e.247\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eMobility of C4/5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.342\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.048\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e.003**\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eDependent Variable: multiple DJD progression. R\u0026sup2; = 0.158. **p\u0026thinsp;\u0026lt;\u0026thinsp;0.01.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eAssociation between Segmental Mobility and multiple DJD progression\u003c/h2\u003e \u003cp\u003eLinear regression analysis revealed distinct kinematic patterns across the cervical regions (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The middle cervical segment (C4/5) demonstrated a statistically significant positive association with the multiple DJD (\u0026szlig; = 0.357, p\u0026thinsp;=\u0026thinsp;0.021). In contrast, the upper (C2/3) and lower (C6/7) segments did not reach statistical significance, indicating that kinematic instability specifically in the middle cervical spine is a key contributor to the degenerative process.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eLinear regression analysis of segmental mobility and multiple DJD progression\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=\"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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCervical Region\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSegment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStandardized \u0026szlig;\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eR\u0026sup2; value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUpper\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC2/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e.242\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.055\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMiddle\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eC4/5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e.357\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e.021*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e.027\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLower\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC6/7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e.216\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.148\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e*p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study investigated the relationship between regional and segmental mobility and the prevalence of cervical DJD, in succession of elucidating the key mechanism of aging which is the crucial factor of DJD. Our principal finding is that hyper-mobility of the middle cervical spine, specifically at the C4/5 segment, is significantly associated with the multiple DJD progression, which signifies that the main mechanism of aging factor is exposure to chronic repetitive movement. This supports the hypothesis that excessive movement causes segmental stress thus leads critical cervical pathogenesis of DJD.\u003c/p\u003e \u003cp\u003eA key finding of this study is the distinct alteration in excessive movement at middle cervical region, especially at C4/5 intervertebral segments. In addition, middle segment and C4/5 segments showed positive correlation with prevalence of DJD. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the control group (No DJD) demonstrated a gradual curve, characterized by a controlled flat pattern (not exceeding range of motion compare to the adjacent segment). This suggests that, in the healthy cervical spine, the C4/5 segment is functionally stabilized by the coordinated movement of neighboring segments (C3/4 and C5/6), preventing stress concentration. Conversely, DJD groups exhibit an excessive movement pattern at C4/5, characterized by focal hyper-mobility due to a failure of controlled motion. This concentration of repetitive mechanical load suggests that segmental instability is a primary driving factor disrupting physiological stress distribution, consistent with previous biomechanical studies (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe finding that C4/5 hyper-mobility, the key mechanism of aging process, was the significant predictor in our regression model is particularly noteworthy. While age is an undeniable factor in the gradual dehydration and structural weakening of intervertebral discs (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e), our study suggests that in a given condition which is mild symptom and middle-aged population (20\u0026ndash;65), abnormal segmental movement appears to be a more immediate and potent contributor to clinically relevant degeneration in addition to aging process. This implies that once a certain age threshold is reached, an individual's unique movement patterns and spinal alignment may play a additional dominant role in determining the location and progress of multiple DJD. Segmental hyper-mobility in the middle cervical region (C4/5) is hypothesized to act as a primary independent contributor to multiple DJD by exerting mechanical stress on adjacent levels and accelerating the degenerative cascade.\u003c/p\u003e \u003cp\u003eThe clinical implication of our finding is meaningful. It is suggested that interventions should not only address pain but also focus on correcting underlying movement pattern abnormality. According to the previous reports, which shows that physical therapy programs aimed at restoring a balanced movement pattern at all cervical segments, rather than allowing for excessive segmental hyper-mobility, could be crucial in preventing the progression of DJD (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Furthermore, the use of dynamic flexion-extension radiographs, which are not always standard practice, may be valuable for identifying patients at risk of accelerated degeneration due to segmental instability, as these can reveal kinematic abnormalities not visible on static images (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThis study has several limitations. First, its retrospective, cross-sectional design prevents the establishment of causality; we can only report an association between hyper-mobility and DJD. A prospective study following a young, asymptomatic cohort would be needed to confirm if hyper-mobility precedes and causes degeneration. Second, we only analyzed motion in the sagittal plane (flexion-extension). Rotational and lateral bending movements, particularly at the C0/1 and C1/2 levels, were not assessed but also can contribute to cervical kinematics. Third, our exclusion of patients with severe, advanced degeneration (Pfirrmann Grade V) means our findings may be limited to those with mild-to-moderate DJD. In advanced stages, segments often become stiff and hypomobile, representing a different phase of the degenerative process. Finally, although we identified a distinct hyper-mobility at the C4/5 segment, this study did not establish a specific quantitative cut-off value for hyper-mobility that predicts the onset of DJD. Future studies with larger cohorts are needed to determine a diagnostic threshold for kinematic instability.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study demonstrates that hyper-mobility of the middle cervical spine region, particularly at the C4/5 segment, is a significant independent factor associated with the multiple progression of cervical DJD. Notably, this regional and segmental hyper-mobility appears to be the key mechanism of aging process which accelerates the multiple DJD progression.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e \u003cp\u003e This study was approved by the Pusan National University Yangsan Hospital Institutional Review Board (IRB No: 05-2021-210). The requirement for informed consent was waived by the IRB due to the retrospective nature of the study.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication:\u003c/strong\u003e \u003cp\u003eNot applicable.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eCompeting interests:\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eThis work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. 2022R1A5A8023404).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eC.H.L. designed the study. H.G.L., S.H.P. and H.C. performed data collection and radiographic measurements. Y.Y.L. conducted statistical analysis. H.G.L. drafted the manuscript. C.H.L. supervised the study and revised the manuscript. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements:\u003c/h2\u003e \u003cp\u003eNot applicable.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFu Z, Xie Y, Li P, Gao M, Chen J, Ning N. Assessing multidisciplinary follow-up pattern efficiency and cost in follow-up care for patients in cervical spondylosis surgery: a non-randomized controlled study. Front Med. 2024;11:1354483.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDu JY, Shafi K, Blackburn CW, Kim HJ, Iyer S, Qureshi S, et al. Trends in costs, reimbursements, and surgeon payments for cervical disc arthroplasty cost of care from 2009 to 2019: Presented at the 2023 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves. J Neurosurgery: Spine. 2023;39(5):690\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarrache M, Harris AB, Puvanesarajah V, Raad M, Hassanzadeh H, Srikumaran U, et al. Hospital payments increase as payments to surgeons decrease for common inpatient orthopaedic procedures. JAAOS Global Res Reviews. 2020;4(4):e20.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJain NS, Nguyen A, Formanek B, Alluri R, Buser Z, Hah R, Wang JC. Cervical disc replacement: trends, costs, and complications. Asian Spine J. 2020;14(5):647.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDi Lella GM, Costantini AM, Monelli E, Guerri G, Leone A, Colosimo C. Diagnostic Imaging in the Degenerative Diseases of the Cervical Spine. Cervical Spine: Minimally Invasive and Open Surgery. Springer; 2022. pp. 33\u0026ndash;61.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSwanson BT, Creighton D. Cervical disc degeneration: important considerations for the manual therapist. J Man Manipulative Therapy. 2022;30(3):139\u0026ndash;53.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTao Y, Galbusera F, Niemeyer F, Samartzis D, Vogele D, Wilke H-J. Radiographic cervical spine degenerative findings: a study on a large population from age 18 to 97 years. Eur Spine J. 2021;30(2):431\u0026ndash;43.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKang X, Qian M, Liu M, Xu H, Xu B. Predictive factors associated with chronic neck pain in patients with cervical degenerative disease: a retrospective cohort study. J Pain Res. 2023:4229\u0026ndash;39.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRajesh N, Moudgil-Joshi J, Kaliaperumal C. Smoking and degenerative spinal disease: a systematic review. Brain spine. 2022;2:100916.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePark C-H, Min K-B, Min J-Y, Kim DH, Seo KM, Kim D-K. Strong association of type 2 diabetes with degenerative lumbar spine disorders. Sci Rep. 2021;11(1):16472.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAo S, Liu Y, Wang Y, Zhang H, Leng H. Cervical kyphosis in asymptomatic populations: incidence, risk factors, and its relationship with health-related quality of life. J Orthop Surg Res. 2019;14(1):322.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMilligan J, Ryan K, Fehlings M, Bauman C. Degenerative cervical myelopathy: diagnosis and management in primary care. Can Fam Physician. 2019;65(9):619\u0026ndash;24.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarrett JM, McKinnon C, Callaghan JP. Cervical spine joint loading with neck flexion. Ergonomics. 2020;63(1):101\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePetersen JA, Brauer C, Thygesen LC, Flachs EM, Lund CB, Thomsen JF. Prospective, population-based study of occupational movements and postures of the neck as risk factors for cervical disc herniation. BMJ open. 2022;12(2):e053999.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSingla D, Veqar Z. Association between forward head, rounded shoulders, and increased thoracic kyphosis: a review of the literature. J Chiropr Med. 2017;16(3):220\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMesregah MK, Repajic M, Mgbam P, Fresquez Z, Wang JC, Buser Z. Trends and patterns of cervical degenerative disc disease: an analysis of magnetic resonance imaging of 1300 symptomatic patients. Eur Spine J. 2022;31(10):2675\u0026ndash;83.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhou C, Wang H, Wang C, Tsai T-Y, Yu Y, Ostergaard P, et al. Intervertebral range of motion characteristics of normal cervical spinal segments (C0-T1) during in vivo neck motions. J Biomech. 2020;98:109418.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYu Y, Mao H, Li J-S, Tsai T-Y, Cheng L, Wood KB, et al. Ranges of cervical intervertebral disc deformation during an in vivo dynamic flexion\u0026ndash;extension of the neck. J Biomech Eng. 2017;139(6):064501.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLoher TJ, B\u0026auml;rlocher CB, Krauss JK. Dystonic movement disorders and spinal degenerative disease. Stereotact Funct Neurosurg. 2006;84(1):1\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChawda S, M\u0026uuml;nchau A, Johnson D, Bhatia K, Quinn N, Stevens J, et al. Pattern of premature degenerative changes of the cervical spine in patients with spasmodic torticollis and the impact on the outcome of selective peripheral denervation. J Neurol Neurosurg Psychiatry. 2000;68(4):465\u0026ndash;71.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeber J, Czarnetzki A, Spring A. Paleopathological features of the cervical spine in the early middle ages: natural history of degenerative diseases. Neurosurgery. 2003;53(6):1418\u0026ndash;24.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu J, Chen B, Hao L, Shan Z, Chen Y, Zhao F. Disc degeneration is easily occurred at the same and adjacent cephalad level in cervical spine when Modic changes are present. J Orthop Surg Res. 2023;18(1):548.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiebsch C, Greiner-Perth A-K, Vogt M, Vieres V, Jonas R, Kienle A, Wilke H-J. Intervertebral disc degeneration, age, and sex affect the range of motion of the cervical spine. Sci Rep. 2025;15(1):23540.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMahmoud NF, Hassan KA, Abdelmajeed SF, Moustafa IM, Silva AG. The relationship between forward head posture and neck pain: a systematic review and meta-analysis. 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J Spine Surg. 2021;7(1):48.\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":"Cervical Vertebrae, Intervertebral Disc Degeneration, Joint Instability, Biomechanics, Range of Motion","lastPublishedDoi":"10.21203/rs.3.rs-8277180/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8277180/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThe aging factor, which appears to be the result of chronic repetitive movement, has been identified as a crucial factor of spinal degenerative joint disease (DJD). However, there has been no study to evaluate the relationship between the amount of movement and the prevalence of DJD. Thus, the purpose of our study was to investigate the relationship between segmental mobility of the cervical spine and the prevalence of DJD, and to compare it with other known etiologic factors of DJD.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA retrospective analysis of cervical radiographs (neutral, flexion, and extension views) and MRI scans of 101 patients with neck pain (28 male, 72 female; mean age 51.51\u0026thinsp;\u0026plusmn;\u0026thinsp;6.78 years) was conducted. Amount of segmental range of motion (ROM) from C2/3 to C6/7 was measured. Patients were categorized into three groups: No DJD, Single DJD, and Multiple DJD. To assess the association between segmental mobility angle, demographic factors and multiple DJD progression, one-way ANOVA and multiple linear regression analyses were performed.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe middle cervical region exhibited the most extensive range of motion, exclusively the C4/5 segment demonstrating the highest mobility (12.70\u0026deg; \u0026plusmn; 5.00\u0026deg;). The most prevalent site for DJD was C6/7 (75, 74.3%). Comparison of the groups by the ANOVA, distinct hyper-mobility pattern was the key factor : while the No-DJD group maintained stable motion at C4/5 (10.20\u0026deg;), both the single and multiple DJD groups exhibited a significant increase in hyper-mobility at this segment (p\u0026thinsp;=\u0026thinsp;0.034). Multiple regression analysis adjusted for confounding factors revealed that C4/5 mobility was a significant independent predictor of multiple DJD progression (\u0026szlig; = 0.342, p\u0026thinsp;=\u0026thinsp;0.003), whereas age, gender, and BMI did not show a significant effect.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThe middle cervical segment (C4/5) showed the greatest range of motion and correlated with the highest prevalence of multiple DJD. Specifically, segmental hyper-mobility at the C4/5 level, characterized by distinct focal hyper-mobility, is strongly associated with the multiple progression of cervical DJD with this correlation outweighing the effect of age.\u003c/p\u003e","manuscriptTitle":"The Effect of Segmental Hyper-Mobility on Development of Cervical Disc Degeneration: a Retrospective Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-22 09:15:54","doi":"10.21203/rs.3.rs-8277180/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":"126ad0f5-700c-4341-9aeb-65211ab3f12f","owner":[],"postedDate":"December 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-22T12:30:58+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-22 09:15:54","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8277180","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8277180","identity":"rs-8277180","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}