Disc degeneration contributes to the denser bone in the subendplate but not in the vertebral body in patients with lumbar spinal stenosis or disc herniation.

BACKGROUND CONTEXT: It is commonly believed that decreased bone quality would lead to endplate degeneration and arthritic changes in the facet joints, and thus accelerated disc degeneration (DD). However, some more detailed studies of vertebral bone structure have found that bone mineral density (BMD) in the vertebral body is increased rather than decreased in moderate or greater disc degeneration. The relationship between BMD and DD still needs further study. MRI-based vertebral bone quality scores have been shown to be effective in reflecting BMD, rendering a new way to evaluate the changes of vertebral body bone with DD using MRI alone. PURPOSE: To evaluate MRI-based vertebral bone quality and Pfirrmann grades in patients with lumbar spinal stenosis or disc herniation, and to identify if DD is associated with denser bone around the endplate. STUDY DESIGN/SETTING: A single-center, retrospective cohort study. PATIENT SAMPLE: A total of 130 patients with lumbar disc herniation and lumbar spinal stenosis from January 2019 to November 2020 who had a complete dual-energy X-ray absorptiometry scan and noncontrast lumbosacral spine MRI data. OUTCOME MEASURES: The vertebral bone quality score (VBQ) and sub-endplate bone quality score (EBQ) was calculated as a ratio of the signal intensity of the vertebral bodies and sub-endplate regions to the signal intensity of the cerebrospinal fluid at L3 on the mid-sagittal T1-weighted MRI images, respectively. The Pfirrmann grades of the lumbar discs were assessed as well. METHODS: The age, gender, body mass index, and T-score of the lumbar spine of the patients were collected. The degeneration grades of the lumbar discs were evaluated according to the Pfirrmann classification. VBQ and EBQ were measured through T1-weighted lumbar MRI. The VBQ and EBQ scores were compared between cranial and caudal sides. The correlation between MRI-based bone quality and DD was calculated. A linear regression model was used to examine the association between DD and adjacent EBQ and VBQ. RESULTS: This study included 569 lumbar segments from 130 inpatients. Cranial and caudal EBQ decreased with the increase of the Pfirrmann grade. The discs with Pfirrmann grade 5 had significantly lower caudal EBQ than the discs with Pfirrmann grades 2, 3, and 4. In the osteoporosis patients, the Pfirrmann grades negatively correlated both with the cranial EBQ and caudal EBQ. Pfirrmann grade greater than 4 was an independent contributor to the cranial EBQ, whereas greater than 3 was an independent contributor to the caudal EBQ. CONCLUSIONS: Disc degeneration grades correlated with the EBQ but not with the VBQ. In patients with lumbar spinal stenosis or disc herniation, DD contributes to the denser bone in the sub-endplate, but not in the whole vertebral body.

Cervical Alignment of Patients with Basilar Invagination: A Radiological Study.

OBJECTIVE: To investigate the cervical alignment and the relative range of motion (ROM) in patients with basilar invagination (BI). METHODS: A total of 40 BI cases (38.1 years old ± 17.9 years old, 19 male and 21 female) and 80 asymptomatic individuals (33.8 years old ± 10.8 years old, 40 male and 40 female) were included. The Skull-C2 /Skull-BV, Skull-C7 , C2 -C7 /BV-C7 wall angles, C0 -C2 /C0 -BV, C0 -C7 , C1 -C7 , and C2 -C7 /BV-C7 angles were measured in dynamic X-ray images (including neutral, extension, and flexion positions). Correlation between the upper and lower cervical curvatures were analyzed. The total, extension, and flexion ROMs of these angles were calculated, respectively. RESULTS: The BI patients had a smaller C0 -C2 /C0 -BV angle (18.2° ± 16.4° vs 30.9° ± 9.3°), but larger C2 -C7 /BV-C7 (32.2° ± 16.1° vs 19.4° ± 10.6°) and C2 -C7 /BV-C7 wall angles (37.8° ± 17.2° vs 23.6° ± 10.2°) than the control group in neutral position. The upper and lower curvatures correlated negatively in neutral (r = -0.371), extension (r = -0.429), and flexion (r = -0.648) positions among BI patients, as well as in extension position (r = -0.317) among control group. The BI patients presented smaller total ROMs in Skull-C2 /Skull-BV (12.3° ± 16.6° vs 19.7° ± 10.9°), C0 -C2 /C0 -BV (8.1° ± 11.1° vs 17.6° ± 10.5°), and C0 -C7 angles (57.8° ± 14.2° vs 78.3° ± 17.9°), but a larger total ROM in C2 -C7 /BV-C7 wall angle (52.8° ± 13.9° vs 27.0° ± 16.1°) than the control group. The BI patients also presented smaller extension ROMs in Skull-C2 /Skull-BV (6.9° ± 9.4° vs 12.5° ± 9.3°), Skull-C7 (24.5° ± 10.9° vs 30.7° ± 12.5°), and C0 -C2 /C0 -BV angles (4.4° ± 7.8° vs 9.9° ± 8.6°) than the control group. Moreover, the BI patients showed smaller absolute values of flexion ROMs in Skull-C2 /Skull-BV (-5.2° ± 9.4° vs -7.3° ± 8.0°), C0 -C2 /C0 -BV (-3.2° ± 8.8° vs -7.7° ± 8.7°), and C0 -C7 angles (-33.2° ± 13.0° vs -52.8° ± 19.2°), but a larger absolute value of flexion ROM in C2 -C7 /BV-C7 wall angle (-33.9° ± 14.8° vs -8.2° ± 15.1°). CONCLUSION: The cervical spine was stiffer in BI patients than the asymptomatic individuals, especially in the upper cervical curvature. The negative correlation between upper and lower cervical curvatures was more obvious in BI patients.