An Investigation Into the Relationship Between the Sedimentation Sign and Lumbar Disc Herniation in Upright Magnetic Resonance Images

STUDY DESIGN

Retrospective Upright MRI Study.

OBJECTIVES

Determine the relationship between lumbar disc herniation and presence of the nerve root sedimentation sign on upright kinematic MRI patients.

METHODS

T2-weighted axial upright kMRI images of 100 patients with the presence of disc herniation in at least 1 lumbar disc between L1/L2 and L5/S1 were obtained. Sedimentation sign, spinal canal anterior-posterior (AP) diameter, disc height, disc herniation size, type of herniation, and zone of herniation were evaluated. A positive sedimentation sign was defined as having either the majority of nerve roots running ventrally or centrally in the canal or conglomeration of the nerve roots at the mid-disc level. Herniation types were defined as either no herniation, disc bulge, protrusion, extrusion, or sequestration. Zones of herniation were categorized as either central, lateral, or far lateral.

RESULTS

The kappa value of intra-observer reliability was .915. The kappa value of disc levels with a negative sedimentation sign were seen more frequently (n = 326, 65.2%) than those with a positive sedimentation sign (n = 174, 34.8%). The spinal canal AP diameter was significantly decreased at the L3/L4 and L4/L5 level in patients with a positive sedimentation sign. Discs with a positive sedimentation sign had a larger average size of disc herniation compared to those with a negative sign at all levels. A relationship between positivity of the sedimentation sign and disc herniation type was significant at L2/L3, L3/L4, and L4/L5.

CONCLUSIONS

Patients with a positive sedimentation sign were seen to have larger disc herniations and more severely degenerated discs.

Analysis of trends in lumbar disc degeneration using kinematic MRI

OBJECTIVE

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

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.

Evaluation of facet joints and segmental motion in patients with different grades of L5/S1 intervertebral disc degeneration: a kinematic MRI study

PURPOSE

This study aimed to evaluate facet joint parameters and osteoarthritis grades, and segmental angular and translational motions among different grades of L5/S1 intervertebral disc (IVD) degeneration.

METHODS

This retrospective study analysed kinematic magnetic resonance imaging (kMRI) images of the lumbar spine of 214 patients with low back pain. Degenerations of the L5/S1 IVDs and facet joints osteoarthritis were assessed using the Pfirrmann and Pathria grading scales, respectively. Facet joint parameters included facet joint angle and facet joint space width. Angular and translation segmental motions were measured using MRI Analyzer software.

RESULTS

The mean age of the studied patients was 44.1 ± 13.9 years. Patients with L5/S1 disc degeneration were associated with higher odds of facet joint osteoarthritis (odds ratio = 2.28, 95% confidence interval = 1.23-4.23, P = 0.008). There was a positive correlation between L5/S1 disc degeneration grade and the facet joint grade (r = 0.365, P > 0.001). Grade IV facet joint osteoarthritis did not appear in grades I or II disc degeneration (P > 0.001). The average facet joint width decreased significantly with increasing Pfirrmann grading (P = 0.017). The difference in facet joint angle between groups was not statistically significant (P = 0.532). The differences in the angular and translational motions were not statistically significant (P = 0.530, and 0.510, respectively).

CONCLUSION

A positive correlation exists between L5/S1 disc degeneration and facet joint osteoarthritis grades. The facet joint space width decreases significantly with increasing grade of disc degeneration.

Thoracic spine disc degeneration, translation, and angular motion: An analysis using thoracic spine kinematic MRI (kMRI)

The aim of this study was to evaluate disc degeneration and kinematic changes in translation and angular motion of the thoracic spine using kinematic MRI (kMRI). 105 thoracic spine kMRI were analyzed from T4-5 to T11-12 using MRAnalyzer3. Translational and angular motion were evaluated in neutral, flexion, and extension positions. Thoracic disc height and disc degeneration grading were measured in the neutral position. Intraclass Correlation Coefficients were used to analyze agreement among three observers. The Friedman's test was used to analyze the difference in disc height, disc degeneration, translational motion, and angular motion. The Wilcoxon-signed rank test was used for post-hoc analysis with a Bonferroni correction. A p-value of 0.00625 was used to establish a statistically significant difference. Analysis using the Friedman's test revealed that translational motion, disc height, and disc degeneration were significantly different from T4-5 to T11-12 (p < 0.001). The T4-5 level showed the least translational motion, while the T10-11 showed the most translational motion. The lower thoracic level (T8-12) showed significantly more translational motion, more advanced disc degeneration, and greater disc height than the upper thoracic level (T4-8, p < 0.001). T11-12 showed the most advanced disc degeneration. There was a significant negative correlation between disc degeneration and translational motion at the upper thoracic level (p = 0.013). The lower thoracic region (below T8) had significantly more translational motion, more advanced disc degeneration, and greater disc height. This information is crucial in further understanding thoracic spinal kinematics and may contribute to determining the stopping level in fusion surgeries involving the thoracic spine.

Small C7-T1 lordotic angle and muscle degeneration at C7 level were independent radiological characteristics of patients with cervical imbalance: a propensity score-matched analysis

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.

Kinematic evaluation of cervical sagittal balance and thoracic inlet alignment in degenerative cervical spondylolisthesis using kinematic magnetic resonance imaging

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.

Kinetic magnetic resonance imaging of the cervical spine: a review of the literature

Study Design Literature review. Objective The purpose of this study is to compile and review the body of literature related to kinetic magnetic resonance imaging (kMRI) of the cervical spine. Methods A review of literature related to kMRI was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Results We included 16 prospective and retrospective studies of symptomatic and asymptomatic patients who underwent kMRI of the cervical spine. Conclusions Data suggest that kMRI is able to provide meaningful information regarding changes in the cervical spine in both normal and pathologic segments. A prospective study comparing magnetic resonance imaging and kMRI is needed to confirm clinically utility of this technology.