Search

Study Design: Retrospective cross-sectional review of a large database., Objective: Little is known regarding extension K-lines for treatment of cervical myelopathy. Therefore, this study seeks to examine differences between K-lines drawn in neutral and extension., Summary of Background Data: The modified K-line is a radiological tool used in surgical planning of the cervical spine. As posterior cervical decompression and fusion often results in patients being fused in a more lordotic position than the preoperative neutral radiograph, a K-line measured in the extension position may offer better utility for these patients., Materials and Methods: Total of 97 patients were selected with T2-weighted, upright cervical magnetic resonance imaging taken in neutral and extension. For each patient, the K-line was drawn at the mid-sagittal position for both neutral and extension. The distance from the most posterior portion of each disk (between C2 and C7) to the K-line was measured in neutral and extension and the difference was calculated. Paired t test was used to assess significant differences., Results: Across all levels between C2 and C7 there was an increase in the distance between the dorsal aspect of the disk and K-line when comparing neutral and extension radiographs. The average change in difference (extension minus neutral) at each cervical spinal level was 0.9 mm (C2-C3), 2.5 mm (C3-C4), 2.6 mm (C4-C5), 2.0 mm (C5-C6), and 0.9 mm (C6-C7). A paired t test showed that the K-line increase from neutral to extension was statistically significant across all disk levels ( P <0.001)., Conclusion: When positioned in extension, patients experience a significant increase in distance from the dorsal aspect of a disk to the K-line compared to when positioned in neutral, especially between C3 and C6. This is clinically relevant for surgeons considering a posterior cervical decompression and fusion in patients with a negative modified K-line on preoperative magnetic resonance imaging, as these patients may have enough cervical cord drift back when fused in an extended position, maximizing likelihood of improving postoperative DSM functional outcomes., Competing Interests: Z.B.—consultancy: Cerapedics (past), Research Support: SeaSpine (past, paid to the institution), Next Science (paid directly to institution), Medical Metrics (past, paid directly to institution), NIH SBIR Subaward (paid to institution); North American Spine Society: committee member; Lumbar Spine Society: Co-chair Educational Committee, AOSpine Knowledge Forum Degenerative: Associate member; AOSNA Research committee—committee member: patents (issued): Biomarkers for painful intervertebral discs and methods of use thereof. R.J.H.: consultant and royalties NuVasive, research support (paid to institution): si-bone and a-tec, committees: NASS, LSRS, editorial board: GSC. J.C.W.: Royalties—Biomet, Seaspine, Synthes, Investments/Options—Bone Biologics, Pearldiver, Electrocore, consulting: precision OS, Board of Directors—AO Foundation, National Spine Health Foundation, Editorial Boards—Global Spine Journal Editor-in-Chief, Fellowship Funding (paid to institution): AO Foundation. R.K.A.: stock options from HIA, Senior Reviewer for IJSS. The remaining authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To evaluate which cervical level is the most appropriate level to measure occipitocervical inclination (OCI)., Methods: Sixty-two patients with multi-positional MRI: 24 males and 38 females, who had cervical lordosis and had a disk degeneration grade of 3 or less were included. We measured patient's OCI at C3, C4, and C5, occipitocervical angle (OCA), occipitocervical distance (OCD), C2-7 angle, and cervical sagittal vertical axis (cSVA) in neutral, flexion, and extension position. The correlation between OCI and OCA, OCD, C2-7 angle, and cSVA on each cervical level in all three positions was tested using Pearson's correlation coefficient test. The difference between OCIs at each cervical level was tested by Wilcoxon signed-rank test. p value of less than 0.05 was set as a statistically significant level., Results: C5 OCI showed statistically significant correlation with OCA, OCD, C2-7 angle, and cSVA in all three positions (p < 0.05, r = 0.214-0.525). C3 OCI in flexion (p = 0.393, r = 0.081) and C4 OCI in neutral and flexion (neutral p = 0.275, r 0.104; flexion p = 0.987, r = 0.002) did not show significant correlation with C2-7 angle. There was a statistically significant difference between C3, C4, and C5 OCIs in neutral and extension position (p < 0.05). At the same time, OCI showed statistically strong correlation between adjacent cervical levels (p < 0.001, r = 0.627-0.822)., Conclusion: C5 cervical level is the most appropriate level for OCI measurement. OCI should be measured at the same cervical level at all time. C4 OCI can reliably substitute C5 OCI in case C5 which is invisible on radiographic image. These slides can be retrieved under Electronic Supplementary Material.

Study Design: Retrospective kinematic MRI (kMRI) study., Objective: To evaluate the dynamic changes of thoracic anterior and posterior space available for cord (SAC), and thoracic spinal cord in the dural sac in three positions., Setting: Expert MRI, Bellflower California; and University of Southern California, in Los Angeles, USA., Methods: A total of 118 patients (66 males and 52 females, mean age ( ± SD) of 45.6 ± 10.6 years) who underwent thoracic spine kMRI were evaluated from T4-5 to T11-12 in flexion, neutral, and extension positions. The anterior SAC, posterior SAC, and mid-sagittal thoracic cord diameter were measured at each level from T4-5 to T11-12. Inter- and intraobserver agreements were analyzed., Results: The anterior SAC was significantly narrower in flexion position compared with other positions at T8-9 to T11-12 levels (p < 0.01). The T8-9 level had significantly wider posterior SAC in flexion and extension positions compared with the neutral position (p < 0.005). However, the posterior SAC at T9-10 was narrower in extension than the neutral position (p = 0.002). Thoracic spinal cord diameter significantly increased in flexion position when compared with the neutral position at T8-9, T9-10, and T11-12 levels (p < 0.005)., Conclusions: Thoracic spinal cord had dynamic changes with positions. In flexion position, the thoracic cord at T8-9 and below tended to move anteriorly, getting closer to the vertebral body and intervertebral disc. The mid-sagittal diameter of the thoracic cord increased in flexion position at the levels below T8-9. In the presence of lesions in anterior epidural space, the risk of spinal cord compression is higher in flexion position, especially at levels below T8-9.

Study Design: Retrospective study of consecutive 113 cervical kinetic magnetic resonance images (kMRIs) and 57 radiographs., Objective: To elucidate the relationship between C2-6 or C2-7 Cobb angle and cervical sagittal alignment parameters using kMRI, and evaluate the visibility of C6 and C7 inferior endplates on cervical radiographs., Summary of Background Data: Several studies have used C2-6 Cobb angle instead of C2-7 Cobb angle as C7 inferior endplate is not always visible because of overlying shadows. However, the relationship between C2-6 or C2-7 Cobb angle and cervical sagittal alignment parameters remains unclear. Moreover, visibility of C6 inferior endplate remains unknown., Methods: C2-6 Cobb angle, C2-7 Cobb angle, occiput-C2 angle, Atlas-dens interval (ADI), narrowest oropharyngeal airway space (nPAS), cervical sagittal vertical axis (cSVA), cervical tilt, cranial tilt, neck tilt, thoracic inlet angle (TIA), and T1 slope were measured using kMRI, and analyzed for their relationship with C2-6 or C2-7 Cobb angle. Visibility rates of C6 or C7 inferior endplates were evaluated using cervical radiographs., Results: Linear regression analysis showed high association between C2-6 and C2-7 Cobb angle (R = 0.696, P < 0.01). C2-6 Cobb angle was significantly correlated with occiput-C2 angle, TIA, T1 slope, neck tilt, cSVA, and cervical tilt; but not with nPAS, ADI, and cranial tilt. C2-7 Cobb angle resembled C2-6 Cobb angle regarding the relationships with other parameters. In our study, 94.7% C6 and 50.9% C7 inferior endplate were clearly visible; 1.8% C6 and 24.6% C7 inferior endplate were invisible. Chi-square test and residual analysis showed significant difference between the two groups (P < 0.01)., Conclusion: C2-6 Cobb angle highly resembled C2-7 Cobb angle regarding its relationships with parameters of craniovertebral, cervical and thoracic inlet alignment. C2-6 Cobb angle could be an alternative to C2-7 Cobb angle because of its significantly higher visibility rate., Level of Evidence: 3.

Purpose: To evaluate the kinematic change of cross-sectional area of lumbar intervertebral foramen in degenerative lumbar spondylolisthesis patients using multi-positional MRI., Methods: Multi-positional MRI was performed on 31 patients diagnosed with single or multilevel degenerative lumbar spondylolisthesis and 31 control patients without degenerative lumbar spondylolisthesis. Foraminal area (FA) was measured at the lumbar spondylolisthesis level in degenerative lumbar spondylolisthesis group and at L3-4, L4-5, and L5-S1 level in the control group. FA was measured bilaterally in neutral, flexion, and extension positions. The difference in FA between the groups was analyzed using Mann-Whitney U test, and the difference between positions within groups was analyzed using Wilcoxon signed-rank test., Results: Degenerative lumbar spondylolisthesis group showed significantly smaller FA on both sides and on average in all three positions compared to the control group (p < 0.05 all). From neutral to flexion position, the change in FA was significantly smaller in the degenerative lumbar spondylolisthesis group than in the control group on both sides and on average (p < 0.005 all). In degenerative lumbar spondylolisthesis group, the FA showed no significant change from neutral to flexion, but showed significant change from neutral to extension (p < 0.005 all)., Conclusions: FA in the degenerative lumbar spondylolisthesis group was smaller than in the control group. There was no difference in FA in degenerative lumbar spondylolisthesis group from neutral to flexion, only from neutral to extension. Patients with degenerative lumbar spondylolisthesis have a higher chance of developing foraminal stenosis.

Background Context: Cervical sagittal vertical axis (cSVA) of ≥40 mm is recognized as the key factor of poor health-related quality of life, poor surgical outcomes, and correction loss after surgery for cervical deformity. However, little is known about the radiological characteristics of patients with cSVA≥40 mm., Purpose: The purpose of this study was to identify the radiological characteristics of patients with cervical imbalance., Design: Retrospective analysis of weight-bearing cervical magnetic resonance (MR) images., Patient Sample: Consecutive 1,500 MR images of symptomatic patients in weight-bearing position., Outcome Measures: Cervical sagittal vertical axis, cervical alignment, cervical balance parameters (T1 slope, Co-C2 angle, C2-C7 angle, C7-T1 angle, neck tilt, and thoracic inlet angle), disc degeneration (Pfirmann and Suzuki classification), end plate degeneration (Modic change), spondylolisthesis (antero- and retrolisthesis), anteroposterior (AP) diameter of dural sac, cross-sectional area (CSA), and fat infiltration ratio of the transversospinalis muscles at C4 and C7 levels., Methods: Patients were divided into two groups: cSVA≥40 mm and cSVA<40 mm. Gender, age, and cervical alignment were analyzed. Subsequently, matched imbalance (cSVA≥40 mm) and control (<40 mm) groups were created using the propensity score to adjust for age, gender, and cervical alignment. Cervicothoracic angular parameters, disc degeneration, Modic change, spondylolisthesis, and degeneration of the transversospinalis muscles at C4 and C7 were compared. Variables with p<.05 were included in the multinomial logistic regression model to identify factors that relate to the cervical balance grouping., Results: The incidence of patients with cervical imbalance was 2.5% (37 patients). Those patients had a higher incidence of kyphosis, were older, and there were more male patients. In the matched imbalance group, the T1 slope was greater (p=.028), C7-T1 lordotic angle was smaller (p<.001), the number of anterolisthesis was greater (p=.012), and the fat infiltration ratio at C4 and C7 was higher (p=.023, 0.030) compared with the control. Logistic regression analysis showed that the C7-T1 angle (adjusted odds ratio [aOR]=0.592, p=.001) and fat infiltration ratio at C7 level (aOR=1.178, p=.030) were significant independent variables., Conclusions: Smaller C7-T1 lordotic angle and severe muscle degeneration at C7 level were independent characteristics of patients with cervical imbalance., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background Context: The thoracic spine was previously known as a relatively stable region in human spine. Several studies reported that the motion of the thoracic spine and changes in the cross-sectional area of the spinal cord changed with positions in the sagittal plane. The kinematic relationship between the thoracic disc and the space available for cord (SAC) with the positional change is still not well investigated., Purpose: The objective of this study was to evaluate the kinematic change of the intervertebral disc and space available for the spinal cord of the thoracic spine using kinematic magnetic resonance imaging (kMRI)., Study Design: This is a retrospective study., Patient Sample: The patient sample included 105 patients who underwent thoracic spine kMRI., Outcome Measurement: Disc bulging and the SAC were evaluated from T4-T5 to T11-T12 in flexion, neutral, and extension positions., Methods: MRAnalyzer3 (TrueMRI Corporation, Bellflower, CA, USA) was used to analyze disc bulging and SAC from T4-T5 to T11-T12. The Friedman test was used to analyze the differences in disc bulging and SAC between neutral, flexion, and extension positions at each segment. The Wilcoxon signed-rank test was used for post hoc analysis for the significant levels from the Friedman test., Results: The mean value of the thoracic intervertebral disc area from T4-T5 to T11-T12 tended to be larger in flexion than in extension. Initial analysis with the Friedman test revealed a significant difference in disc bulging at T8-T9, T9-T10, and T11-T12 among the three positions (p<.05). Post hoc analysis showed that disc bulging was only significant at T8-T9 between flexion and extension (p<.001), at T9-T10 between neutral and flexion (0.003), and at T9-T10 between flexion and extension (p=.004). The SAC from T4-T5 to T11-T12 tended to be widest in extension and narrowest in flexion. Only T5-T6 exhibited a statistically significant difference in SAC between flexion and extension (p=.002)., Conclusions: The thoracic discs and the SAC from T4-T5 to T11-T12 showed kinematic changes from flexion to extension. The thoracic spinal canal tended to be narrowest in flexion and widest in the extension. Thus, kyphotic deformities could be one of the etiologies for neurogenic deterioration in patients with thoracic myelopathy., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Study Design: Retrospective study., Objective: To evaluate how each type of sagittal cervical alignment affects the motion of the upper and subaxial cervical spine using kinematic magnetic resonance imaging., Summary of Background Data: The sagittal malalignment of the cervical spine from degeneration in the subaxial cervical spine reflects a disruption in the kinematic properties of the cervical spine and affects the motion of adjacent segments. Changes in the sagittal parameters and kinematics of the upper cervical spine and upper thoracic spine due to the kyphosis are unknown., Methods: Kinematic magnetic resonance imaging of the cervical spine in neutral position from 311 patients, including 90 lordotic, 90 straight, 90 global kyphotic, and 41 segmental kyphotic were analyzed. The lordotic angle at the upper and lower cervical spine, and T1 slope were measured in the neutral position and again in flexion and extension for dynamic analysis., Results: The number of levels with significant disk degeneration was higher in the global kyphosis group. In the global kyphosis group, neutral sagittal parameters showed some characteristics of compensation to the malalignment. Compared with the lordotic group, patients with global kyphosis demonstrated significantly higher lordotic angle of the upper cervical spine and more horizontal T1 slope. The dynamic evaluation showed greater range of motion of the entire cervical spine and subaxial cervical spine in younger patients. However, we still found greater range of motion of the occipito-atlanto-axial complex in global kyphosis, even when controlling for age and number of levels with significant disk degeneration., Conclusion: Sagittal malalignment of the cervical spine affects all parts of the cervical motion complex. The global kyphotic alignment of subaxial cervical spine affects the kinematic properties of the occipito-atlanto-axial complex and upper thoracic spine to compensate for the alteration of cervical alignment. These differences are not seen in straight and segmental kyphosis., Level of Evidence: Level 3.

Purpose: Although the T1 vertebra is considered as an important factor of cervical balance, little is known about its motion between flexion and extension. The purpose of present study was to analyze the T1 sagittal motion using kinematic magnetic resonance imaging (kMRI), and to identify factors that relate to T1 sagittal motion., Methods: We retrospectively analyzed 145 kMR images taken in weight-bearing neutral, flexion and extension positions. Cervical balance parameters were evaluated in each position. The degree of T1 sagittal motion was defined as [(T1 slope at extension) - (T1 slope at flexion)]. All patients were divided into three groups: Positive group (T1 followed the head motion, T1 sagittal motion > 5°), Stable group (5 ≥, ≥ - 5) and Negative group (T1 moved in the opposite direction from the head motion, > - 5). The groups were compared and multivariate logistic regression analysis was calculated., Results: There were 57 (40%) patients in the positive, 56 (39%) in the stable and 32 (22%) in the negative group. The positive group had the largest C2-7 sagittal vertical axis in flexion (p < 0.001) and the shortest in the extension (p = 0.023). Similar trends were seen in cranial tilt and cervical tilt. The value of T1 height < 27 mm was a significant independent factor for the negative group (p = 0.008, adjusted odds ratio = 5.958)., Conclusion: Based on T1 sagittal motion, 40% of the patients were classified in positive group (the T1 vertebra followed the head motion in flexion and extension), and 20% were classified in the negative group (the T1 vertebra moved in the opposite direction from the head motion). T1 height < 27 mm was a potential predictor of negative group.

Purpose: To test the reliability and validity of the multi-positional magnetic resonance imaging (MRI) in measuring cervical angular parameter using the standard dynamic cervical X-ray as a reference., Methods: All patients who underwent both cervical dynamic plain radiograph and multi-positional MRI on the same day between 2010 and 2016 were included in this study. The C2-7 angle and the segmental angles of the C2-3 to C6-7 segments were measured in all three positions (neutral, flexion, and extension) using multi-positional MRI and dynamic radiograph. The Pearson's correlation coefficients and linear regression analysis were used for statistical analysis., Results: 46 patients were enrolled in this study. All angular parameters showed significant positive correlation between multi-positional MRI and dynamic X-ray (p < 0.05). The angle of C2-7 showed significantly positive correlation between multi-positional MRI and X-ray (r = 0.552-0.756). All segmental angles from C2-3 to C6-7 showed moderate correlation (r = 0.401-0.636). The linear regression analysis showed that C2-7 angles and all angular parameters had significant correlation between multi-positional MRI and dynamic X-ray (p < 0.05, R 2  = 0.107-0.571)., Conclusions: The C2-7 angle and segmental cervical angles measured by multi-positional MRI were valid, and reliability substituted the dynamic X-ray measurement within the acceptable range of error. Multi-positional MRI can be used as a reliable tool for angular parameter measurement and detection of angular instability in the cervical spine.

Study Design: Retrospective analysis of consecutive 45 radiographs and 120 kinematic magnetic resonance images (kMRI) OBJECTIVE.: The aim was to assess the visibility of C7 and T1 endplates on radiographs, and to verify the correlation between C7 or T1 slope and cervical balance parameters using kMRI., Summary of Background Data: Because the T1 slope is not always visible due to the anatomical interference, several studies have used C7 slope instead of T1. However, it is still unclear whether the C7 endplate is more visible on radiographs than T1, and if C7 slope has similarity with T1 slope., Methods: The endplate visibility was determined using weight-bearing radiography. Subsequently, using weight-bearing MR images, the C7 slope of upper and lower endplate, T1 slope, C1 inclination, C2 slope, atlas-dens interval (ADI), C2-C7 lordotic angle, cervical sagittal vertical axis (cSVA), cervical tilt, cranial tilt, neck tilt, thoracic inlet angle (TIA) were measured, for the analysis of correlation between three types of slopes and cervical balance parameters., Results: 82% of the upper C7, and 18% of T1 endplate were clearly visible. The upper C7 endplate was significantly visible, whereas T1 endplate was significantly invisible (residual analysis, P < 0.01). Linear regression analysis showed correlation between the upper C7 slope and T1 slope (R = 0.818, P < 0.01) and, lower C7 slope and T1 slope (R = 0.840, P < 0.01). T1 slope significantly correlated with neck tilt, TIA, C2-C7 angle, cSVA, cervical and cranial tilt, but not with the C1 inclination, C2 slope, and ADI. Upper and lower C7 slopes showed the close resemblance with T1 slope in terms of correlation with those parameters., Conclusion: Both, upper and lower C7 slope correlated strongly with T1 slope and showed similar relationship with cervical balance parameters as T1 slope. Therefore, C7 slope could potentially substitute T1 slope, especially upper C7 slope due to the good visibility., Level of Evidence: 3.

The objective of the study is to identified the correlation between Modic changes (MCs), disc degeneration, motions (translation and angulation) and facet osteoarthritis in lumbar spine. 425 patients who underwent multi-positional lumbar MRI were reviewed. A total of 2250 lumbar spinal segments in neutral position were evaluated for MCs, disc degeneration grading, translation and angulation motion, and facet osteoarthritis. The chi-square test, Kruskal-Wallis, Mann-Whitney U test, Pearson's correlation and linear regression were used to test for statistically significant difference between parameters. MCs type 2 showed the most translational motion. The presence of MCs was significantly correlated with advanced disc degeneration (grade 4-5, Odds ratio 6.29, 95% CI 4.48-8.83) and the presence of facet osteoarthritis (Odds ratio 9.50, 95% CI 6.18-14.62). The presence of facet osteoarthritis had significantly more translation motion than non-osteoarthritis facet (p=0.04). The facet osteoarthritis grade was positively correlated with disc degeneration grade (r=0.309, p-value<0.001). The facet osteoarthritis correlated with the presence of MCs and more translation motion. The severity of facet osteoarthritis was correlated with the advanced disc degeneration. The MCs, translation motion, and disc degeneration were the significant parameters which affected lumbar facet osteoarthritis., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Purpose: The purpose of this study was to examine the movement of the spinal cord and its relationship to the spinal canal in patients with mild spondylosis using kinetic magnetic resonance imaging (kMRI)., Methods: Weight-bearing, multiposition kMRI was performed on symptomatic patients through a full range of flexion-extension. A total of 52 study patients were selected based on the C2-C7 Cobb angle of sagittal alignment: lordotic (from 30 to 45 degrees). We evaluated dynamic changes in different parameters from flexion-extension: spinal canal diameter (CD), spinal cord diameter (SCD), space available for the cord, anterior space available for the cord (ASAC), posterior space available for the cord (PSAC), average distance between the anterior canal and the cord (d-value), and global angle for the spinal canal and cord., Results: The CD tended to decrease from flexion to extension from C3/C4 to C6/C7, however, there were no significant differences at the proximal and distal levels, C2/C3 and C7/T1. There were no significant differences of SCD between different postures. The SCD tended to decrease from C2/C3 to C7/T1. The ASAC followed the same pattern as CD-values. The ASAC was narrowest at C4/C5 and C5/C6. The PSAC tended to increase from C2/C3 to C7/T1. The spinal cord shifted anteriorly with extension and posteriorly with flexion. In addition, the spinal cord maintained its curve with the movement., Conclusions: The kinematics of spinal cord motion may be associated with the pathogenesis of cervical spondylotic myelopathy. However, the spinal cord maintains its curve with position changes. Consequently, different motions of the cervical spine may affect spinal cord migration and cause changes in ASAC and PSAC.

Purpose: To investigate the relationship between the facet fluid sign (FFS) and kinematics of affected lumbar segment in patients with low-grade, single-level lumbar degenerative spondylolisthesis using kinematic magnetic resonance imaging (kMRI).Materials and methods Ninety-two patients diagnosed with low-grade (Grade 1 or 2), single level lumbar degenerative spondylolisthesis L3 to S1. Angular and translational motion, whole lumbar motion, slip percentage, and facet angle were measured. Disc degeneration and degrees of osteoarthritis were graded, facet effusion was evaluated and classified as Positive or Negative FFS (PosFFS or NegFFS).Results There were significant differences in the facet degeneration, translational motion, percentage of total angular motion, and flexion-extension slip difference between the PosFFS and NegFFS group. 28.3% of the patients in PosFFS group had anterolisthesis in flexion, but not extension.There was a significant difference in the incidence of FFS between the dynamic and static spondylolisthesis (75% vs 35%, p < 0.001). If FFS was present on kMRI, a positive predictive value for dynamic spondylolisthesis was 75.6%. with the sensitivity and specificity of 0.75 and 0.65 for posFFS to diagnose dynamic DS. The likelihood ratio for dynamic slips in the presence of FFS was 2.1, and the likelihood ratio for static slips in the presence of FFS was 1.1.Conclusion Facet fluid sign was present in weight-bearing neutral position, and the presence of FFS in kMRI increased the probability of having dynamic spondylolisthesis., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Purpose: To investigate the changes of lumbar neural foramina size during dynamic motion using positional MRI., Methods: Two hundred and fifty neural foramina from 50 patients were analyzed. Lumbar foraminal height, width, and area parameters from L1 to S1 were evaluated for changes in extension, neutral, and flexion positions on T2 parasagittal positional MRI images, and were correlated to lumbar angular motion. One-way analysis of variance (ANOVA) and post hoc analysis were used to examine the differences between levels and positions., Results: Compared to the neutral position, almost all lumbar foraminal parameters (height, width at inferior level, and area) increased in flexion and decreased in extension at all levels, except for L5-S1 foraminal width at superior and middle levels. The foraminal height and area in all lumbar segments except L5-S1 increased as the lumbar angular motion changed from extension to flexion in <40° group. The foraminal width increased significantly at L3-4 and L4-5 among all groups., Conclusion: Lumbar foraminal dimensions increased in flexion compared to neutral and extension positions. Lumbar angular motion contributed to the changes of foraminal height and area at most of the segments, while it affected foraminal width only at L3-4 and L4-5. This information can be useful in the understanding of patient symptoms and the correlation with the imaging studies with dynamic foraminal stenosis. Furthermore, data from our study may help with patient positioning for foraminal injections or endoscopic surgery.

Study Design: This is a cross-sectional radiologic study., Objective: The purpose of this study was to assess radiologic features related to dynamic changes of dural sac diameter using kinematic magnetic resonance imaging., Summary of Background Data: It is well known that the cross-sectional area of the lumbar spinal canal decreases during movement from flexion to extension. However, the radiologic characteristics related to dynamic changes of the lumbar spinal canal have not been elucidated., Methods: A total of 453 consecutive patients with clinically symptomatic low back pain or radiculopathy were recruited to undergo lumbar kinematic magnetic resonance imaging. The study participants consisted of 271 males (60%) and 182 females (40%). The average age was 44.5±12.2 years old. We investigated the following measurements at each level from L3-L4 to L5-S1: dural sac diameter, ligamentum flavum thickness, disk bulge, disk degeneration, angular motion, translational motion, and posterior disk height. The odds ratios (ORs) for ≥2 mm change of dural sac diameter between flexion and extension were calculated., Results: The average dural sac diameter was 12.2 mm in neutral, 12.5 mm in flexion, and 11.7 mm in extension, with an average difference between flexion and extension of 0.83 mm. The OR of a ≥2 mm change in L5-S1 was 0.55 as compared with L3-L4. Significantly increased ORs were observed with ≥3 mm of ligamentum flavum in neutral (OR: 4.05), 3-3.9 and ≥4 mm of disk bulge in neutral (ORs: 1.62 and 1.81, respectively), grade IV and V disk degeneration (OR: 2.59 and 2.86, respectively), ≥8 degrees of angular motion (OR: 1.81), and ≥2 mm of posterior disk height change (OR: 1.84)., Conclusions: Several radiologic characteristics related to the dynamic change of dural sac diameter have been demonstrated.

Study Design: A retrospective kinematic magnetic resonance imaging (kMRI) study., Objective: To evaluate the utility of kMRI in determining the relationship between cervical sagittal balance and TI alignment., Summary of Background Data: Thoracic inlet parameters play an important role in cervical spine sagittal balance. However, most of the literature is based on lower resolution cervical X-rays or CT scans in the supine position., Methods: Cervical spine kMRI of 83 patients with degenerative cervical spine conditions (20-68 yr of age) was analyzed for: (1) cervical spine parameters: C2-C7 angle, C2-C7 sagittal vertical axis (SVA), cranial tilt, and cervical tilt; and (2) T1 parameters: thoracic inlet angle (TIA), T1 slope, and neck tilt (NT). Multiple logistic regression analysis and Pearson correlation coefficients were performed., Results: The mean TIA, T1 slope, and NT were 78.0, 33.2, and 44.8°, respectively. The mean C2-7 angle, SVA of C2-C7, cervical tilt, and cranial tilt were -15.4°, 22.0 mm, 18.1°, and 15.1°, respectively. The ratio of cervical:cranial tilt was maintained as 55:45%. A significant correlation was found between the C2-C7 angle and T1 slope (r = 0.731), TIA and C2-C7 angle (r = 0.406), cervical tilt with C2-C7 angle (r = 0.671), T1 slope with TIA (r = 0.429), TIA with neck tilt (r = 0.733), TIA with cervical tilt (r = 0.377), SVA C2-C7 with cervical tilt (r = -0.480), SVA C2-C7 with cranial tilt (r = 0.912), and C2-7 SVA with the ratio of cranial tilt to cervical tilt (r = 0.694)., Conclusion: An individual with a large T1 slope required large cervical lordosis to preserve physiologic sagittal balance of the cervical spine. Cranial tilt was the cervical parameter most strongly correlated with SVA C2-C7, and thus may be a good parameter to assess decompensation of cervical sagittal balance., Level of Evidence: 3.

Purpose: A retrospective radiographic study was carried out to analyze the effect of lumbar disc herniation on the kinetic motion of adjacent segments., Methods: A total of 162 patients with low back pain or radicular pain in the lower limbs without a prior history of surgery were evaluated using kinetic magnetic resonance imaging. Translational motion, angular variation, and disc height were measured at each segment from L1-L2 to L5-S1. Other factors including the degree of disc degeneration, age, gender, and vertebral segment location were analyzed to determine any predisposing risk factors for segmental instability adjacent to disc herniations., Results: Spinal levels above the disc herniation exhibited, on average, a 6.4 % increase in translational motion per mm of disc herniation (P = 0.496) and a 21.4 % increase in angular motion per mm herniation (P = 0.447). Levels below the herniation demonstrated a 5.2 % increase in translational motion per mm of disc herniation (P = 0.428) and a decrease of 10.7 % in angular motion per mm (P = 0.726). The degree of disc degeneration had no significant correlation with adjacent level motion. Similarly, disc herniation was not significantly correlated with disc height at adjacent levels, although there was a significant relationship between gender and adjacent segment disc height., Conclusions: Although disc height, translational motion, and angular variation are significantly affected at the level of a disc herniation, no significant changes are apparent in adjacent segments. Our results indicate that herniated discs have no effect on range of motion at adjacent levels regardless of the degree of disc degeneration or the size of disc herniation, suggesting that the natural progression of disc degeneration and adjacent segment disease may be separate, unrelated processes within the lumbar spine.

Study Design: Retrospective radiographical study., Objective: To define the relationship between the grade of disc degeneration and the motion of the lumbar spine by using kinetic magnetic resonance imaging., Summary of Background Data: Disc degeneration is common after middle age. Lumbar instability has generally been recognized as a potential risk factor of low back pain. However, correlations between the grade of disc degeneration and the motion of the lumbar spine need more investigation., Methods: Kinetic magnetic resonance imaging was performed in 162 patients with symptomatic low back pain without prior history of surgery. The lumbar intervertebral discs were graded by spine surgeons according to the degenerative grading system (grades I-V). Translational motion and angular variation were measured at each segment from L1-L2 through L5-S1. The relationship between the degree of lumbar disc degeneration and extent of lumbar spine mobility was analyzed., Results: The translational motion in discs with grade I through IV increased gradually, but decreased with grade V. Compared with other less degenerative grades, grade V discs had significantly decreased total intervertebral translational motion (P < 0.05). The angular variation in discs with grade I through IV was fairly constant, but decreased with grade V. Compared with other degenerative grades (I-IV), grade V discs had significantly decreased total intervertebral translational motion (P < 0.05). For less degenerative grades I and II discs, the L2-L3 and L3-L4 segmental units contributed the majority of total angular mobility of the spine. However, for the severely degenerated segments, grade V discs, the contributions of the L2-L3 and L3-L4 significantly decreased (P < 0.01)., Conclusion: As disc degeneration developed from the normal to an increasingly severe stage, the motion of lumbar spine progressed from the normal stage to an unstable phase with higher mobility and finally to an ankylosed stage where stability was increased., Level of Evidence: 3.

Purpose: To determine if adding flexion and extension MRI studies to the traditional neutral views would be beneficial in the diagnosis of cervical disc bulges., Methods: Five hundred patients underwent MRI in neutral, flexion and extension positions. The images were analyzed using computer software to objectively quantify the amount of disc bulge., Results: Compared to the neutral position, cervical disc bulges were significantly increased in the extension position (P < 0.05), but on flexion position, there was no significant difference (P > 0.05). For patients without or <3 mm of disc bulge in neutral, 2.97% demonstrated an increase in bulge to ≥3 mm bulge in flexion, and 16.41% demonstrated an increase to ≥3 mm bulge in extension. For patients in the neutral view that had a baseline disc bulge of 3-5 mm, 3.73% had increased bulges to ≥5 mm in flexion and 11.57% had increased bulges to ≥5 mm in extension., Conclusion: A significant increase in the degree of cervical disc bulge was found by examining extension views when compared with neutral views alone. Kinematic MRI views provide valuable added information, especially in situations where symptomatic radiculopathy is present without any abnormalities demonstrated on traditional neutral MRI.

Identifying the etiology of pain for patients suffering from chronic low-back pain remains problematic. Noninvasive imaging modalities, used in isolation, have not consistently provided sufficient evidence to support performance of a lumbar fusion. Provocative testing has been used as an adjunct in this assessment, either alone or in combination with other modalities, to enhance the diagnostic capabilities when evaluating patients with low-back pain. There have been a limited number of studies investigating this topic since the publication of the original guidelines. Based primarily on retrospective studies, discography, as a stand-alone test, is not recommended to formulate treatment strategies for patients with low-back pain. A single randomized cohort study demonstrated an improved potential of discoblock over discography as a predictor of success following lumbar fusion. It is therefore recommended that discoblock be considered as a diagnostic option. There is a possibility, based on a matched cohort study, that an association exists between progression of degenerative disc disease and the performance of a provocative discogram. It is therefore recommended that patients be counseled regarding this potential development prior to undergoing discography.

Study Design: This is a retrospective analysis of lumbar segmental motion using Kinetic magnetic resonance imaging(KMRI)., Objective: The aim of the study was to investigate lumbar segmental motion in functional (ie, standing weight-bearing flexion and extension) positions and examine the effects of lumbar disk degeneration on lumbar segmental motion., Summary of Background Data: Various biomechanical studies using cadaveric specimens have demonstrated the effects of disk degeneration on lumbar motion. However, the studies did not determine the effect of disk degeneration on segmental motion in the functional, living spine., Methods: Segmental range of motion (ROM) was calculated and disk degeneration was graded in patients who had undergone KMRI in weight-bearing neutral, 60 degrees of flexion, and 20 degrees of extension. Patients (n=262) were categorized as having normal disks (n=94), single-level degeneration at L4–L5 (n=28) or L5–S1 (N=71), or double-level degeneration at L4–L5–S1 (N=69). Angular ROM, contribution (%)of each segment to total lumbar motion, and contribution of motion from upper (L1–L3) and lower (L4–S1) lumbar levels were compared., Results: Mean ROMo f the lumbar spine in the normal group was 41.3±13.3 degrees. The L4–L5 degeneration group (36.1±12.4 degrees) and the L4–L5–S1 degeneration group (37.1±12.5 degrees) showed significantly decreased total lumbar ROM compared with the normal group. The ROM in upper lumbar segments was significantly larger than that in the lower segments in the normal group and similar in the degeneration groups. The contribution of L5–S1 to total lumbar motion was the smallest of all segments, and no significant difference was found between all groups., Conclusions: In functional positions assessed utilizing weight bearing KMRI, segmental motion at levels with degenerated disks was decreased. The contribution of upper lumbar segments to the total lumbar motion was not smaller than that of the lower segments. The L5–S1 level showed the smallest ROM in lumbar motion.

Study Design: Retrospective analysis using positional MRI., Objective: To determine the effects of total sagittal lordosis on spinal kinematics and degree of disc degeneration in the lumbar spine., Summary of Background Data: Changes in sagittal lordosis alter the load on the spine and may affect spinal mobility. There is increasing recognition of the clinical impact that sagittal alignment has on back pain, especially its possible role in accelerating adjacent segment degeneration after spinal fusion. However, its relationship to segmental mobility and degeneration of the lumbar spine has yet to be determined., Methods: Four hundred and thirty patients who had low back pain with or without leg pain (241 males and 189 females) with a mean age of 42.98 years (range, 16-85 years) were included. Total sagittal lordosis (T12-S1) was divided into three groups; Group A: Straight or Kyphosis (<20°, n = 84), Group B: Normal lordosis (20-50°, n = 294), and Group C: Hyperlordosis (>50°, n = 52). The degree of disc degeneration was graded using midsagittal T2-weighted MR images. Segmental mobility, including translational motion and angular variation, was measured using positional MRI. Their relationship with total segmental lordosis was identified., Results: When compared with group B, the segmental motion in group C tended to be lower at the border of lordosis and higher at the apex of lordosis, with a significant difference in angular motion at L2-L3. The contrary finding was identified in group A, which had a higher segmental motion at border segments and lower motion at apical segments of lordosis, with significant difference of translational motion at L3-L4 and angular motion at L1-L2. Apical segments contributed more, whereas border segments contributed less to the total angular mobility in more lordotic spines. The opposite was seen in more kyphotic spines. Disc degeneration tended to be greater at all levels in group C, and at L1-L2 and L5-S1 in group A., Conclusion: Changes in sagittal alignment may lead to kinematic changes in the lumbar spine. This may subsequently influence load bearing and the distribution of disc degeneration at each level. Sagittal alignment, disc degeneration, and segmental mobility likely have a reciprocal influence on one another.

Object: Degenerative changes of the interspinous ligaments (ISLs) have generally been ignored in previous studies. Factor-related causes, the effects that these changes have on other structures within the spinal functional unit, and their relation to kinematic changes in the spine are lacking. In this study, the authors evaluated the reliability of a proposed MR imaging grading system of ISL degeneration (ISLD). They also investigated the relationship between ISLD and aging, disc/facet joint degeneration, and lumbar segmental motion., Methods: The authors studied 256 lumbar motion segments from L-2 to S-1 in 64 patients (35 men and 29 women) with a mean age of 46.08 years (range 23–85 years). An MR imaging–based grading system for ISLD was developed and ranged from Grade A (mild) to Grade D (severe). The reliability was tested, and the correlation of the grade with the severity of the disc and facet joint degeneration was examined. The segmental motion of each functional unit was measured using flexion/extension MR imaging, and their relationships with ISL grades were identified., Results: Grade A was observed in 115 levels (44.9%), Grade B in 105 (41.0%), Grade C in 15 (5.9%), and Grade D in 21 levels (8.2%). The kappa coefficients for intraobserver and interobserver agreements were substantial to excellent (intraobserver [0.871] and interobserver [0.721–0.807]). Grade D was observed primarily in elderly patients. Segmental motion tended to decrease in the most severe grade, with a significant difference in angular mobility. As the severity of ISLD increased, the severity of disc/facet joint degeneration increased (p < 0.001 and p < 0.05, respectively)., Conclusions: The authors proposed a reliable and reproducible grading system that may be used to investigate spinal kinematics in association with ISLD. The authors' findings illustrated the distribution of ISLD grades. The most severe grade occurred primarily in elderly patients. Mobility decreased in the most severe grade; therefore, the stage of ISLD should be taken into consideration when evaluating spinal stability.

Posterior spinal ligament pathology is becoming increasingly recognized as a significant cause of low back pain. Despite the growing clinical importance of interspinous ligament degeneration in low back pain patients, formal reliability studies for the magnetic resonance imaging (MRI) evaluation of interspinous ligaments have not been performed. We proposed an MRI classification system for interspinous ligament degeneration and conducted a comprehensive reliability and reproducibility assessment. Fifty patients who had low back pain with or without leg discomfort (26 males and 24 females) with a mean age of 48.8 years (range 23-85 years) were studied. The classification for lumbar interspinous ligament degeneration was developed on the basis of the literature using mid-sagittal T1- and T2-weighted images. Three spine surgeons independently graded a total of 200 interspinous ligament levels. Intraobserver and interobserver reliability were assessed by kappa statistics. The frequency of disagreement was also identified. The intraobserver agreement was excellent in all readers (kappa range 0.840-0.901). The interobserver agreement was lower as expected, and was substantial to excellent (kappa range 0.726-0.818). Overall complete agreement was obtained in 87.8% of all interspinous ligament levels. A difference of 1, 2, and 3 grades occurred in 8.1, 3.0, and 1.1% of readings, respectively. This proposed MRI classification of interspinous ligament degeneration was simple, reliable, and reproducible. Its use as a standardized nomenclature in clinical and radiographic research may be recommended.

Study Design: Retrospective radiographic review., Objective: To investigate the effects of cervical disc herniation on kinematics at adjacent vertebral motion segments., Summary of Background Data: Kinetic magnetic resonance imaging (kMRI) is an alternative method to conventional MRI, which allows evaluation of the cervical spine in a more physiologic, weight-bearing position, and acquisition of images in flexion, extension, and neutral alignment. kMRI has previously been used to evaluate the effects of disc degeneration on cervical kinematics., Methods: A total of 407 patients with neck pain without prior history of surgery were evaluated using kMRI. Translational motion, angular variation, and disc height were measured at each segment from C2-C3 through C7-T1. Other factors including the degree of disc degeneration, age, gender, and vertebral segment location were analyzed in order to determine any predisposing risk factors for segmental instability adjacent to disc herniations., Results: Spinal levels above the disc herniation exhibited, on average, a 7.2% decrease in translational motion per mm of disc herniation (P = 0.0113), without significant change in angular motion. Levels below the herniation demonstrated a 5.2% decrease in angular motion per mm of disc herniation (P = 0.0236) without significant change in translational motion. The degree of disc degeneration had no significant effect on adjacent level motion. Disc herniation had no significant impact on disc height at adjacent levels, although disc degeneration correlated with decreased disc height above and increased disc height below., Conclusion: Although disc height, translational motion, and angular variation are significantly affected at the level of a disc herniation, no significant changes are apparent in adjacent segments. Our results indicate that herniated discs have no effect on ROM at adjacent levels regardless of the degree of disc degeneration or the size of disc herniation, suggesting that the natural progression of disc degeneration and adjacent segment disease may be separate, unrelated processes within the cervical spine.

Object: The authors conducted a retrospective observational study using kinetic MR imaging to investigate the relationship between instability, abnormal sagittal segmental motion, and radiographic variables consisting of intervertebral disc degeneration, facet joint osteoarthritis (FJO), degeneration of the interspinous ligaments, ligamentum flavum hypertrophy (LFH), and the status of the paraspinal muscles., Methods: Abnormal segmental motion, defined as > 10 degrees angulation and > 3 mm of translation in the sagittal plane, was investigated in 1575 functional spine units (315 patients) in flexion, neutral, and extension postures using kinetic MR imaging. Each segment was assessed based on the extent of disc degeneration (Grades I-V), FJO (Grades 1-4), interspinous ligament degeneration (Grades 1-4), presence of LFH, and paraspinal muscle fatty infiltration observed on kinetic MR imaging. These factors are often noted in patients with degenerative disease, and there are grading systems to describe these changes. For the first time, the authors attempted to address the relationship between these radiographic observations and the effects on the motion and instability of the functional spine unit., Results: The prevalence of abnormal translational motion was significantly higher in patients with Grade IV degenerative discs and Grade 3 arthritic facet joints (p < 0.05). In patients with advanced disc degeneration and FJO, there was a lesser amount of motion in both segmental translation and angulation when compared with lower grades of degeneration, and this difference was statistically significant for angular motion (p < 0.05). Patients with advanced degenerative Grade 4 facet joint arthritis had a significantly lower percentage of abnormal angular motion compared to patients with normal facet joints (p < 0.001). The presence of LFH was strongly associated with abnormal translational and angular motion. Grade 4 interspinous ligament degeneration and the presence of paraspinal muscle fatty infiltration were both significantly associated with excessive abnormal angular motion (p < 0.05)., Conclusions: This kinetic MR imaging analysis showed that the lumbar functional unit with more disc degeneration, FJO, and LFH had abnormal sagittal plane translation and angulation. These findings suggest that abnormal segmental motion noted on kinetic MR images is closely associated with disc degeneration, FJO, and the pathological characteristics of interspinous ligaments, ligamentum flavum, and paraspinal muscles. Kinetic MR imaging in patients with mechanical back pain may prove a valuable source of information about the stability of the functional spine unit by measuring abnormal segmental motion and grading of radiographic parameters simultaneously.

Study Design: This was a radiographic reliability study of a novel grading system for cervical intervertebral disc degeneration., Objectives: This study aimed to develop and test the reliability of a reproducible grading system for cervical intervertebral disc degeneration on the basis of the routine magnetic resonance imaging (MRI)., Summary of Background Data: Cervical disc degeneration is common after middle age, and the morphology of cervical disc degenerative disease has often been studied using MRI. There are few specific MRI-based grading systems for cervical intervertebral disc degeneration despite the clinical importance of this problem. This study proposes a novel reproducible grading system for cervical disc degeneration and demonstrates the reliability of this classification scheme., Methods: A grading system for cervical intervertebral disc degeneration was developed based on relevant previous literature. MRI grading of 300 cervical intervertebral discs using T2-weighted sagittal images was performed by 4 spinal surgeons (observers) in a blinded fashion. Intraobserver and interobserver reliabilities were assessed by calculating kappa statistics., Results: Grade I degeneration was observed in 27 discs (9.0%); grade II, in 56 (18.7%); grade III, in 124 (41.3%); grade IV, in 67 (22.3%); and grade V, in 26 (8.7%) discs. Kappa coefficients for intraobserver and interobserver agreements ranged from substantial to excellent (intraobserver, 0.907 to 0.950 and interobserver, 0.730 to 0.826). Complete agreement was obtained, on an average, in 72.1% of the discs. A difference of 1, 2, and 3 grades was observed in 22.4%, 3.3%, and 0.2% discs, respectively., Conclusions: This grading system is comprehensive and easily applicable with sufficient reproducibility. It can be used as a common nomenclature for research and discussions.

Object: Appropriate animal models of disc degeneration are critical for the study of proposed interventions as well as to further delineate the degenerative process. The purpose of this study was to characterize a porcine model for disc degeneration confirmed on magnetic resonance (MR) imaging studies and histological analysis., Methods: Twelve miniature pigs were used (weight 48-65 kg) to study degeneration in the lumbar spine. Under fluoroscopic guidance, the disc was percutaneously punctured with a 3.2-mm-diameter trephine to a 5-mm depth into the annulus fibrosus. Control and experimental levels were randomized among 6 levels in the lumbar spine. The unlesioned spinal levels were used as controls and were compared with lesioned levels. Magnetic resonance imaging grading and disc height were serially recorded preoperatively, and at 5, 8, 19, 32, and 39 weeks postoperatively. The animals were killed in groups of 3 at 7, 18, 32, and 41 weeks postinjury, and the discs were examined histopathologically., Results: Consistent, sequential, and progressive degeneration of the annular injury was observed on MR imaging and histopathological studies from the time of injury to the final time point. The disc height and the disc height index also sequentially decreased from the time of the injury in a consistent manner. The uninjured control levels did not show any progressive degeneration and maintained their normal state., Conclusions: Based on MR imaging and histopathological findings, the authors demonstrated and characterized a reliable model of sequential disc degeneration in miniature pigs with percutaneous injury to the annulus fibrosus. In the early stages, as soon as 5 weeks after injury, significant disc degeneration was seen on MR imaging grading with decreases in disc height. This degeneration did not improve by the final time point of 39 weeks.

Study Design: A novel dynamic magnetic resonance imaging (MRI) system, kinetic MRI (kMRI), was used to study lumbar disc herniations., Objective: The objective of this study was to determine if adding flexion and extension MRI studies to the traditional neutral views would be beneficial in the diagnosis of lumbar disc herniations., Summary of Background Data: Prior studies demonstrate that only 70% of patients with lumbar disc herniations based on physical examinations are confirmed by MRI studies. Recently, kMRI delivers the ability to scan patients in neutral, flexion, and extension positions, which may allow for improved diagnosis of this problem., Methods: Five hundred fifty-three patients underwent kMRI with assessment of the degree of disc bulge in neutral and flexion and extension. The images were analyzed using computer measurement technology to objectively quantify the amount of disc herniation., Results: For patients with normal or <3 mm of disc bulge in neutral, 19.46% demonstrated an increase in herniation to >3 mm bulge in extension, and 15.29% demonstrated an increase to >3 mm bulge in flexion. For patients in the neutral view that had a baseline disc bulge of 3 to 5 mm, 13.28% had increased herniations to >5 mm in extension and 8.47% had increased herniations to >5 mm in flexion. For patients with a baseline disc bulge of 5 to 7 mm in neutral, 10.58% increased in extension and 5.78% increased in flexion. In addition, for patients with a baseline disc bulge of 7 to 9 mm in neutral, 9.09% increased in extension and 4.55% increased in flexion., Conclusion: A significant increase in the degree of lumbar disc herniation was found by examining flexion and extension views when compared with neutral views alone. kMRI views provide valuable added information, especially in situations where symptomatic radiculopathy is present without any abnormalities demonstrated on conventional MRI.

Background Context: There is limited information describing the correlation between the initial quantitative measurements on magnetic resonance imaging (MRI) scans of disc herniation area, canal cross-section areas, percent canal compromise, and disc herniation location to the need for surgery., Purpose: Our aim is to determine if the size of disc herniation area, canal cross-section area, percent canal compromise, and disc herniation location taken from MRI images of patients with symptomatic single-level lumbar herniated intervertebral discs upon initial presentation to a spine surgeon, were predictive of the need for surgical treatment., Study Design/setting: This is a retrospective case matched study of patient MRI images in the senior author's private practice., Patient Sample: From a pool of 332 patients with sciatica caused by lumbar intervertebral disc herniations at our institution, 65 patients had surgery, of which MRI images were available and analyzed on 44 patients. Forty-four additional patients were randomly selected from the remaining 267 original group as nonoperative controls., Methods: The axial MRI image showing the largest canal compromise by the herniated disc was selected for measurements. Using T1- and T2-weighted images, the areas of interest were digitally scanned at high resolution. The canal area and disc herniation area measurement were calculated from the total number of pixels per cross-sectional area, multiplied by a scan correction factor, mm(2) /pixel. Disc herniation locations were classified into either central or paracentral. The percent canal compromise was obtained by disc herniation area divided by canal cross-section area and multiplied by 100., Results: The surgical group's overall mean herniated disc area was 219.6 square millimeter (mm(2)), 179.8 at L4-5, and 267.4 at L5-S1. The nonoperative group's overall mean herniated disc area was 178.4 mm(2), 135.1 at L2-3, 160.3 at L4-5, and 207.4 at L5-S1. The surgical group's overall mean canal cross-sectional area was 471.8 mm(2), 418.6 at L4-5, and 535.6 at L5-S1. The nonoperative group's overall mean canal cross-sectional area was 541.3 mm(2), 518.1 at L2-3, 446.8 at L4-5, and 669.9 at L5-S1. The overall percent canal compromise ratio in the surgery group was 46.7%, 44.1% at L4-5, and 49.8% at L5-S1. The overall percent canal compromise in the nonoperative group was 34.2%, 34.1% at L2-3, 36.1% at L4-5, and 31.8% at L5-S1. The percent canal compromise in central herniations at L4-5 level was 53.0% in the surgical group, and 32.8% in the nonoperative group; at the L5-S1 level surgical group percent canal compromise was 64.1% and in the nonoperative group canal compromise was 27%. L4-L5 level paracentral herniations canal compromise was 36.7% in the surgical group compared with 42.5% canal compromise in the nonoperative group. At the L5-S1 level the canal compromise was 45% in the surgical group and 34.8% in the nonoperative group., Conclusions: Our findings show a trend for patients treated with surgery to have larger disc herniation areas and smaller canal cross-section areas, corresponding to larger percent canal compromise than the nonoperative group. Centrally located herniations followed this trend closely at all levels studied. However, the paracentral herniation at the L4-5 level does not follow this trend, possibly because paracentral disc herniation clinical course is determined more by herniation location rather than the overall herniation size.

Purpose: Current decision-making in multilevel cervical fusion weighs the potential to protect adjacent levels and reduce reoperation risk by crossing the cervicothoracic junction (C7/T1) against increased operative time and risk of complication. Careful planning is required, and the planned distal and adjacent levels should be assessed for degenerative disc disease (DDD). This study assessed whether DDD at the cervicothoracic junction was associated with DDD, disc height, translational motion, or angular variation in the adjacent superior (C6/C7) or inferior (T1/T2) levels. Methods: This study retrospectively analyzed 93 cases with kinematic MRI. Cases were randomly selected from a database with inclusion criteria being no prior spine surgery and images having sufficient quality for analysis. DDD was assessed using Pfirrmann classification. Vertebral body bone marrow lesions were assessed using Modic changes. Disc height was measured at the mid-disc in neutral and extension. Translational motion and angular variation were calculated by assessing translational or angular motion segment integrity respectively in flexion and extension. Statistical associations were assessed with scatterplots and Kendall's tau. Results: DDD at C7/T1 was positively associated with DDD at C6/C7 (tau = 0.53, p < 0.01) and T1/T2 (tau = 0.58, p < 0.01), with greater disc height in neutral position at T1/T2 (tau = 0.22, p < 0.01), and with greater disc height in extended position at C7/T1 (tau = 0.17, p = 0.04) and at T1/T2 (tau = 0.21, p < 0.01). DDD at C7/T1 was negatively associated with angular variation at C6/C7 (tau = − 0.23, p < 0.01). No association was appreciated between DDD at C7/T1 and translational motion. Conclusion: The association of DDD at the cervicothoracic junction with DDD at the adjacent levels emphasizes the necessity for careful selection of the distal level in multilevel fusion in the distal cervical spine. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective upright MRI study. Objective: To validate the presence of positive and negative nerve root sedimentation signs on multi-positional MRI in the upright position and explore the relationship between negative nerve root sedimentation and gravity. Methods: T2-weighted axial multi-positional images in the upright position at the intervertebral disc levels from L1–L2 to L4–L5 in 141 patients with non-specific low back pain were retrospectively assessed. A positive sedimentation sign was defined as the absence of nerve root sedimentation or the absence of dorsal conglomeration of nerve roots within the dural sac. A negative sedimentation sign was defined as nerve root sedimentation dorsally or dorso-laterally like a horseshoe. Intra-and inter-observer reliability was evaluated. The relationship between sedimentation sign and dural sac cross-sectional area (CSA), anterior-posterior (AP) diameter was also explored. Results: The kappa value of intra-observer reliability was 0.962 and inter-observer reliability was 0.925. Both positive and negative sedimentation signs did appear at all 4 lumbar levels, including L1/2, L2/3, L3/4 and L4/5. A positive sedimentation sign was associated with significantly decreased dural sac CSA and AP diameter at L2/3, L3/4 or L4/5 level when compared to negative sedimentation sign. Conclusions: Both negative and positive sedimentation signs appeared at the L1/2, L2/3, L3/4, and L4/5 levels on the upright MRI, which suggested that the presence of nerve roots sedimenting dorsally in patients may not be associated with gravity. Moreover, the current study supports that sedimentation signs on multi-positional MRI images could have the same diagnostic functions as on MRI images. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the trends and patterns of cervical degenerative disc disease in the cervical spine in different age groups of symptomatic patients.Methods: Overall, 1300 symptomatic patients who had undergone cervical spine MRI from February 2019 to November 2021 were included. Pfirrmann grading was used to evaluate the IVD degeneration. Patients were divided into five groups based on age: group 1 from 20 to 29 years, group 2 from 30 to 39 years, group 3 from 40 to 49 years, group 4 from 50 to 59 years, and group 5 from 60 years and above. The patterns, severity, and the number of degenerated levels in each age group were analysed.Results: The total number of degenerated IVDs (grades IV and V) increased significantly with age, ranging from 76 (4.9%) in group 1 to 677 (43.4%) in group 5. The most common degenerated levels were C2/3 (25% of the total degenerated levels) in group 1, C5/6 (29.0%) in group 2, C5/6 (33.1%) in group 3, C5/6 (31.3%) in group 4, C5/6 (24.8%), in group 5. The number of degenerated IVDs increased significantly with age (P < 0.001). In patients with two or more degenerated levels, contiguous-level disc degeneration was more common than skip lesions.Conclusion: This study evaluated the severity and pattern of cervical disc degeneration at each level in different age groups. The severity and number of degenerated levels increased significantly with increased age. Adjacent-level degeneration is more common than skip lesions in patients with more than one-level degeneration. [ABSTRACT FROM AUTHOR]

Study Design: Cross-sectional study. Purpose: To evaluate lumbar disc degeneration (LDD) on magnetic resonance imaging (MRI) in symptomatic subjects to accumulate baseline data on the pattern of degeneration. Overview of Literature: LDD plays an important role in the diagnosis and treatment of low-back pain in patients. Few studies have focused on the pattern of LDD to understand how the lumbar spine ages. Methods: This study included 1,095 patients (mean age, 44.29 years; range, 16-85 years) who underwent upright lumbar MRI. LDD was graded into five categories (I-V). Positive LDD was defined as grade III or greater. The prevalence and pattern of LDD were analyzed, and the correlations between age and total grade of LDD were evaluated. Results: The average number of LDD levels and the total grade of LDD increased with age. LDD moved cephalad with age. The rate of LDD increased rapidly during the decade before the prevalence of LDD and became >50%. In the single-level LDD group, the levels L5-S1 were the most common levels (60.3%). In the two-level group, L4-L5 and L5-S1 were the most common levels (53.5%). In the three-level group, L3-L4, L4-L5, and L5-S1 were the most common levels (55.7%). In the multilevel LDD group, contiguous multilevel disc degeneration (CMDD) was more common than the skipped level disc degeneration (SLDD). The levels L4-L5 were the most common levels in the CMDD group, and L5-S1 were the most common levels among SLDD. Conclusions: LDD was found to correlate with age, and the specific patterns and rates of LDD depended on lumbar disc level and age. These LDD pattern data can be used before spinal procedures to predict the probability of natural LDD progression with age. [ABSTRACT FROM AUTHOR]

Study Design: It is a retrospective analysis of 1806 consecutive cervical magnetic resonance images taken in weight-bearing flexion, neutral, and extension positions.Objective: The aim was to identify the kinematic characteristics of patients with cervical imbalance. Additionally, factors were analysed in the neutral position that could predict the characteristics. Little is known about the kinematic characteristics during cervical flexion and extension positions of the patient with cervical imbalance (cervical sagittal vertical axis (cSVA) in neutral position ≥ 40 mm).Methods: After evaluating the whole images, cervical imbalance group (cSVA ≥ 40 mm, n = 43) and matched control group (< 40 mm, n = 43) were created using propensity score adjusting for age, gender, and cervical alignment. They were compared for cervical motion, changes in disc bulge, and ligamentum flavum (LF) bulge from flexion to extension. Multinomial logistic regression analysis and receiver operating characteristic curve analysis were calculated to verify the predictive factors and cut-off value of the identified characteristics.Results: There were no significant differences in range of motion and the change in bulged discs. There was significant difference in the presence of LF bulge from flexion to extension (p = 0.023); the incidence of LF bulge increased sharply from neutral to extension in imbalance group, while there was linear increase in control group. The canal diameter (odds ratio = 0.61, p = 0.002) and disc height (odds ratio = 1.60, p = 0.041) showed significant relationship with the segments with LF bulge observed in extension but not in neutral position in the imbalance group; the cut-off values were 10.7 mm for canal diameter (sensitivity 82.5%, specificity 66.7%) and 7.1 mm for disc height (70.8%, 58.5%).Conclusion: Patients with cervical imbalance had a stark increase in LF bulge from the neutral to extension position. Canal diameter < 10.7 mm and disc height > 7.1 mm on neutral images may predict the segments with LF bulge observed in extension, but not in the neutral position.Level Of Evidence: II (Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding). These slides can be retrieved from Electronic Supplementary Material. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective, observational, case series. Purpose: To elucidate the prevalence of degenerative changes in the cervical and lumbar spine and estimate the degenerative changes in the cervical spine based on the degeneration of lumbar disc through a retrospective review of magnetic resonance (MR) images. Overview of Literature: Over 50% of middle-aged adults show evidence of spinal degeneration. However, the relationship between degenerative changes in the cervical and lumbar spine has yet to be elucidated. Methods: A retrospective review of positional MR images of 152 patients with symptoms related to cervical and lumbar spondylosis with or without a neurogenic component was conducted. The degree of intervertebral disc degeneration (IDD) was assessed on a grade of 1-5 for each segment of the cervical and lumbar spine using MR T2-weighted sagittal images. The grades across all segments were summed to produce the degenerative disc score (DDS) for the cervical and lumbar spine. The patients were divided into two groups based on the IDD grade for each lumbar segment: normal (grades 1 and 2) and degenerative (grades 3-5). Results: DDSs for the cervical and lumbar spine were positively correlated. Significant differences in cervical DDSs between the groups were observed in all lumbar segments. Although there were no significant differences in cervical DDSs among the degenerative lumbar segment, cervical DDSs at the L1-2 and L2-3 segments tended to be higher than those at the L3-4, L4-5, and L5-S degenerative segments. Conclusions: Our study shows that participants with degenerative changes in the upper lumbar segments are more likely to have a certain amount of cervical spondylosis. This information could be used to lower the incidence of a missed diagnosis of cervical spine disorders in patients presenting with lumbar spine symptomology. [ABSTRACT FROM AUTHOR]

Concern has been raised because of reports of inflammatory swelling following the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human bone morphogenetic protein-7 (rhBMP-7). The purpose of this study is to compare the inflammatory action of rhBMP-7 with those of rhBMP-2. ELISA assays (IL-6, TNF-α) were used to measure the cytokine response to different concentrations of rhBMP-7 and -2. Recombinant human BMP-7 was absorbed into absorbable collagen sponges and different amounts were implanted either subcutaneously (SC) or intramuscularly (IM) into the backs of rats. Using MRI and MIPAV software, we measured the degree of soft tissue edema at 3 h and at 2, 4, and 7 days postoperatively. After sacrificing rats on day 7 the inflammatory zone and mass were measured and the tissue examined histologically. Soft tissue edema after rhBMP-7 and rhBMP-2 implantation was dose-dependent and peaked at 3 h for the subcutaneous implants and at 2 days for the intramuscular implants. RhBMP-7 was associated with a significantly smaller soft tissue edema volume than was rhBMP-2 only at the highest dose (20 µg/ml). Both rhBMP-2 and rhBMP-7 triggered dose-dependent inflammatory reactions. Compared to rhBMP-2, rhBMP-7 is associated with somewhat smaller soft tissue edema volumes. Although rhBMP-7 is associated with an inflammatory reaction leading to soft tissue edema, at high doses this response is significantly less than that seen with rhBMP-2. Our animal model can be used to test materials that could ameliorate this reaction. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1985-1994, 2012 [ABSTRACT FROM AUTHOR]

A congenitally narrow cervical spinal canal has been established as an important risk factor for the development of cervical spondylotic myelopathy. However, few reports have described the mechanism underlying this risk. In this study, we investigate the relationship between cervical spinal canal narrowing and pathological changes in the cervical spine using positional magnetic resonance imaging (MRI). Two hundred and ninety-five symptomatic patients underwent cervical MRI in the weight-bearing position with dynamic motion (flexion, neutral, and extension) of the cervical spine. The sagittal cervical spinal canal diameter and cervical segmental angular motion were measured and calculated. Each segment was assessed for the extent of intervertebral disc degeneration and cervical cord compression. Based on the sagittal canal diameter, the subjects were classified into three groups: A, subjects with a congenitally narrow canal, diameter of less than 13 mm; B, subjects with a normal canal, diameter of 13–15 mm; C, subjects with a wide canal, diameter of more than 15 mm. When compared with Groups A and B, the disc degeneration grades at the C3-4, C5-6, and C6-7 segments and the cervical cord compression scores at the C3-4 and C5-6 segments showed significant differences. Additionally, when compare with Groups A and C, the disc degeneration grades at all segments, except C2-3, and the cervical cord compression scores at all segments, except C2-3, showed significant differences. With respect to the cervical kinematics, few differences in the kinematics were observed between Groups B and C, however, the kinematics in Group A was different with other two groups. In Group A, the segmental mobility at the C4-5 and C6-7 segments were significantly higher than those observed in Group B, and the segmental mobility at the C3-4 segment was significantly lower than that observed in Groups B or C. We demonstrated the unique pathological and kinematic traits of cervical spine that exist in a congenitally narrow canal. We hypothesize that kinematic trait associated with a congenitally narrow canal may greatly contribute to pathological changes in the cervical spine. Our results suggest that cervical spinal canal diameter of less than 13 mm may be associated with an increased risk for development of pathological changes in cervical intervertebral discs. Subsequently, the presence of a congenitally narrow canal can expose individuals to a greater risk of developing cervical spinal stenosis. [ABSTRACT FROM AUTHOR]

By providing a more detailed representation of human anatomy, magnetic resonance imaging (MRI) has expanded our understanding of many of the pathologic conditions that affect the spine. Recent developments in MRI technology has made it possible for surgeons to use this modality intraoperatively to visualize soft tissue and bony structures for diagnostic and therapeutic purposes without the ionizing radiation associated with computerized tomography scans, conventional fluoroscopy, or plain radiographs. This article provides a brief overview of both the current and the theoretical applications of intraoperative/interventional MRI for spinal surgery. [ABSTRACT FROM AUTHOR]

The number of spinal procedures utilizing metallic implants has significantly increased in the past decade. Unfortunately, a small percentage of the cases are complicated by spinal infections in the setting of instrumentation. The clinical, laboratory, and radiographic assessment of this difficult patient population can be quite challenging to even the astute clinician. Traditional radiographic techniques including CT scan and MRI are significantly less useful in this situation secondary to the confusing postoperative changes and the presence of internal fixation. In this article, we review the nuclear medicine imaging modalities which can be used to assist in the diagnosis and management of patients with postoperative spinal infections with metallic implants. These include 99Technetiumm-methylene diphosphonate (99Tcm-MDP) scan, SPECT scan, three-phase bone scan, 67Gallium citrate scan, 111Indium oxine labeled leukocytes scan, 18-F-Fluoro-deoxy-d-glucose (FDG) labeled PET scanning, as well as combinations of the different modalities. Combinations of the radiopharmaceutical isotope scans and the new FDG PET scan appear to demonstrate the most optimal sensitivity and specificity for infection detection in this patient population. [ABSTRACT FROM AUTHOR]

The aim of the current study was to classify and analyze trends in lumbar disc degeneration across age, sex, and disc level using weightbearing kinematic MRI. Between January 2019 and July 2019, 1198 cases were retrospectively analyzed with kinematic MRI. Patients were divided into 5 groups based on age (20–29, 30–39, 40–49, 50–59, and 60+) and evaluated using the Pfirrmann classification to assess for disc degeneration at 5 vertebral levels: L1/2, L2/3, L3/4, L4/5, and L5/S1. Trends in degeneration were analyzed with regression and time series. The L5/S1 vertebral disc had the highest prevalence of severe degeneration across all age groups. The most common multi-level degeneration combinations were L4/5 and L5/S1 for two levels and L3/4, L4/5, and L5/S1 for three levels. All vertebral levels showed significant difference in mean Pfirrmann grade among the age groups (p < 0.001 at all levels). Statistically significant differences in mean Pfirmmann grade among males and females were found only in ages 20–29 and 30–39, in which males showed more degeneration. Our findings using kinematic MRI demonstrate that degeneration increases with age and is most severe in the L5/S1 disc. In multi-level degeneration the most prevalent combinations are those that are contiguous and include L5/S1. Young males were more likely to have degeneration than young females, but there was no significant difference from the fifth decade of life on. • Lumbar disc degeneration increases in severity with age. • Men tend to degenerate at an earlier age than women. • The 5th decade of life is most common for people to develop severe degeneration. [ABSTRACT FROM AUTHOR]

Cervical intervertebral disc (IVD) degeneration is a common cause of neck and arm pain in adults and a frequent finding in imaging studies. This study aimed to assess the age-related degenerations of the cervical IVDs at each cervical spinal level in different age groups using the kinematic magnetic resonance imaging (KMRI). Cross-sectional study using KMRI. This study included 1300 symptomatic patients who had undergone upright cervical spine KMRI from February 2019 to November 2021. Pfirrmann classification of intervertebral disc degeneration. Patients were divided into five equal groups, each with 260 patients based on their ages. Group 1 included patients from 20 to 29 years, group 2 from 30 to 39 years, group 3 from 40 to 49 years, group 4 from 50 to 59 years, and group 5 were patients aged 60 years and above. On T2-weighted sagittal MRI, Pfirrmann grading system was used to grade the IVD degeneration into five grades. Considerable disc degeneration was reported with a Pfirrmann grade IV or V. A total of 7800 cervical IVDs from C2/3 to C7/T1 were evaluated. The severity and pattern of IVD degeneration in each age group was analyzed. Overall, 4.4% of discs were grade I, 21.0% grade II, 55.1% grade III, 17.1% grade IV, and 2.5% grade V. The number of degenerated discs increased gradually with age groups; 4.9%, 8.4%, 16.4%, 24.6%, and 43.4% in groups 1, 2, 3, 4, and 5, respectively, P < 0.001. In group 1, the most common grade was grade II (41.5%), and the most common degenerated level was C2/3 (25%). In group 2, the most common grade was grade III (53.1%), and the most common degenerated level was C5/6 (29.0%). In group 3, the most common grade was grade III (60.2%), and the most common degenerated level was C5/6 (33.1%). In group 4, the most common grade was grade III (67.0%), and the most common degenerated level was C5/6 (31.3%). In group 5, the most common grade was grade III (56.0%), and the most common degenerated level was C5/6 (24.8%). In all groups, C7/T1 was the least common degenerated disc (6.6%, 3.1%, 3.5%, 4.7% and 8.7% in groups 1, 4 and 5, respectively). In groups 1 and 2, 92.1% and 86.3% of subjects, did not have considerable disc degeneration. In group 5, 19.5% of patients had 2-level disc degeneration, 15.5% had 3-level disc degeneration, and the incidence of 6-level degeneration was 11.2%. In patients with single-level disc degeneration, C5/6 was the most common degenerated level (45.3%). In patients with 2-level degeneration, C5/6 and C6/7 were the most common (49.7%). In patients with 3-level degeneration, C4/5, C5/6, and C6/7 were the most common (38.5%). In patients with 4-level degeneration, C2/3, C3/4, and C5/6 were the most common (36.2%). Skip-level degeneration was found in 18.2%, 30.2%, and 20.3% of patients with 2-level, 3-level, and 4-level degeneration, respectively. This study evaluated the severity and pattern of IVD degeneration at each level of the cervical spine in different age groups. The number and severity of degenerated discs increases with age. Adjacent-level degeneration is more common than skip-lesion degeneration in patients with multilevel disc degeneration. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background Context: T1 slope is a novel thoracic parameter used to assess cervical spine sagittal balance. Thoracic index (TI) parameters including T1 slope and cervical sagittal alignment parameters may play an important role in degenerative cervical spondylolisthesis (DCS). Current literature regarding the relationship between TI and cervical sagittal alignment parameters in patients with DCS is limited.Purpose: (1) To evaluate the T1 slope, cervical sagittal alignment, and thoracic inlet parameter in patients with DCS using kinematic magnetic resonance imaging (kMRI), and (2) to find a correlation between the T1 slope, TI, and other cervical sagittal parameters in patients with DCS.Design/setting: Retrospective kMRI study, Level III.Patient Sample: Fifty-two patients with DCS from 1,128 patients from a cervical kMRI database.Outcome Measures: T1 slope, C2-C7 angle, sagittal vertical axis C2-C7 (SVA C2-C7), cranial tilt, cervical tilt, neck tilt, and thoracic inlet angle (TIA).Methods: Cervical spine kMRIs of 52 patients with DCS (mean age 51.7±standard deviation) were analyzed in neutral, flexion, and extension positions. Patients with DCS were divided into two groups: anterolisthesis (N=33) and retrolisthesis (N=19). Each listhesis group was subclassified into grade 1 (slip 2-3 mm) and grade 2 (slip>3 mm).Results: Grade 2 retrolisthesis had the largest T1 slope followed by grade 1 retrolisthesis, grade 2 anterolisthesis, and grade 1 anterolisthesis. Significant differences were found between the anterolisthesis and the retrolisthesis groups in the neutral position (p=.025). The flexion position had the largest T1 slope and showed a significant difference with anterolisthesis in the neutral position (p=.041). Sagittal vertical axis C2-C7 showed strong correlation with cranial tilt in all DCS groups and all positions.Conclusions: In our study, T1 slope was larger in grade 2 DCS, and the retrolisthesis group had larger T1 slope than the anterolisthesis group. Presence of larger T1 slope was significantly correlated with larger cervical lordosis curvature. Furthermore, cranial tilt was strongly correlated with SVA C2-C7. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective kinematic magnetic resonance imaging (kMRI) study. Objective: To evaluate the utility of kMRI in determining the relationship between cervical sagittal balance and TI alignment. Summary Of Background Data: Thoracic inlet parameters play an important role in cervical spine sagittal balance. However, most of the literature is based on lower resolution cervical X-rays or CT scans in the supine position. Methods: Cervical spine kMRI of 83 patients with degenerative cervical spine conditions (20-68 yr of age) was analyzed for: (1) cervical spine parameters: C2-C7 angle, C2-C7 sagittal vertical axis (SVA), cranial tilt, and cervical tilt; and (2) T1 parameters: thoracic inlet angle (TIA), T1 slope, and neck tilt (NT). Multiple logistic regression analysis and Pearson correlation coefficients were performed. Results: The mean TIA, T1 slope, and NT were 78.0, 33.2, and 44.8°, respectively. The mean C2-7 angle, SVA of C2-C7, cervical tilt, and cranial tilt were -15.4°, 22.0 mm, 18.1°, and 15.1°, respectively. The ratio of cervical:cranial tilt was maintained as 55:45%. A significant correlation was found between the C2-C7 angle and T1 slope (r = 0.731), TIA and C2-C7 angle (r = 0.406), cervical tilt with C2-C7 angle (r = 0.671), T1 slope with TIA (r = 0.429), TIA with neck tilt (r = 0.733), TIA with cervical tilt (r = 0.377), SVA C2-C7 with cervical tilt (r = -0.480), SVA C2-C7 with cranial tilt (r = 0.912), and C2-7 SVA with the ratio of cranial tilt to cervical tilt (r = 0.694). Conclusion: An individual with a large T1 slope required large cervical lordosis to preserve physiologic sagittal balance of the cervical spine. Cranial tilt was the cervical parameter most strongly correlated with SVA C2-C7, and thus may be a good parameter to assess decompensation of cervical sagittal balance. Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Background Context: Bulging of ligamentum flavum can happen with the aging process and can lead to compression of the spinal cord and nerves. However, the distribution and the risk factors associated with a missed ligamentum flavum bulge (LFB) are unknown.Purpose: The aim was to evaluate the distribution and risk factors associated with missed LFB in the cervical spine.Study Design: This was a retrospective analysis of kinematic magnetic resonance images (kMRI).Patient Sample: Patients diagnosed with symptomatic neck pain or radiculopathy between March 2011 and October 2012 were included.Outcome Measures: The outcome measures were missed LFB and degenerative factors.Methods: A total of 200 patients (1,000 cervical segments) underwent upright kMRI in neutral, flexion, and extension postures. The LFB, sagittal cervical angles, disc herniation, disc degeneration, disc height, angular motion, translational motion, age, and gender were recorded. After excluding segments with LFB in neutral and flexion position, Pearson and Spearman correlation coefficients were used to evaluate the relation between the risk factors and missed LFB in the extension position.Results: The average depth of LFB was 0.24±0.71 mm at C2-C3, 1.02±1.42 mm at C3-C4, 1.65±1.48 mm at C4-C5, 2.13±1.37 mm at C5-C6, and 1.05±1.54 mm at C6-C7. The distribution of LFB was the most frequent at C5-C6 level (76.58%) followed by C4-C5 (63.06%). Disc herniation, disc degeneration, angular variation, and translational motion were significantly correlated with missed LFB at C4-C5 andC5-C6. Disc degeneration was the only factor significantly correlated with missed LFB at all cervical segments.Conclusions: Occurrence and depth of missed LFB was the highest at C4-C5 and C5-C6 compared with other cervical levels. Disc degeneration, disc herniation, angular variation, and translational motion could play a role in the development of LFB at C4-C5 andC5-C6. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective radiographical study. Objective. To define the relationship between the grade of disc degeneration and the motion of the lumbar spine by using kinetic magnetic resonance imaging. Summary of Background Data. Disc degeneration is common after middle age. Lumbar instability has generally been recognized as a potential risk factor of low back pain. However, correlations between the grade of disc degeneration and the motion of the lumbar spine need more investigation. Methods. Kinetic magnetic resonance imaging was performed in 162 patients with symptomatic low back pain without prior history of surgery. The lumbar intervertebral discs were graded by spine surgeons according to the degenerative grading system (grades I-V). Translational motion and angular variation were measured at each segment from L1-L2 through L5-S1. The relationship between the degree of lumbar disc degeneration and extent of lumbar spine mobility was analyzed. Results. The translational motion in discs with grade I through IV increased gradually, but decreased with grade V. Compared with other less degenerative grades, grade V discs had significantly decreased total intervertebral translational motion ( P < 0.05). The angular variation in discs with grade I through IV was fairly constant, but decreased with grade V. Compared with other degenerative grades (I-IV), grade V discs had significantly decreased total intervertebral translational motion ( P < 0.05). For less degenerative grades I and II discs, the L2-L3 and L3-L4 segmental units contributed the majority of total angular mobility of the spine. However, for the severely degenerated segments, grade V discs, the contributions of the L2-L3 and L3-L4 significantly decreased ( P < 0.01). Conclusion. As disc degeneration developed from the normal to an increasingly severe stage, the motion of lumbar spine progressed from the normal stage to an unstable phase with higher mobility and finally to an ankylosed stage where stability was increased. [ABSTRACT FROM AUTHOR]