Analysis of trends in lumbar disc degeneration using kinematic MRI

Mitochondrial DNA variation and intervertebral disc degeneration: a genotypic analysis in a South African cohort

BACKGROUND

Non-communicable diseases are multifactorial in that they can be caused by genetic factors, age, sex and poor lifestyle choices. They are estimated to account for 71% of deaths globally with 80% of these deaths occurring in low- and middle-income countries. This is particularly true for Intervertebral Disc Degeneration associated with mitochondrial dysfunction. Interestingly, mitochondrial dysfunction can arise from mutations in both the nuclear and the mitochondrial genomes. The present study, therefore, aimed to determine if there is an association between mitochondrial DNA mutations associated with mitochondrial dysfunction and disc degeneration in a South African cohort, and in addition, generate genetic data for understudied mutations in African populations.

METHODS AND RESULTS

Mutations were selected using a systematic literature review. DNA was collected using buccal swabs and extracted using a standard salt-lysis protocol. Mass-array genotyping was done for previously reported as well as novel mutations. GenAlEx (version 6.5), RStudio and SHEsis were used for statistical analyses. Although no significant associations were found, the identified polymorphic mutations C16223T, A10398G and A8536G were found to have higher mutant allele frequencies in case individuals indicating that had a larger cohort been used, significance may have been observed.

CONCLUSIONS

This study was able to generate genotypic information for a South African cohort for both reported and understudied mutations. Furthermore, the identification of higher mutant allele frequencies for C16223T, A10398G and A8536G highlights the importance of considering these mutations in future studies using a larger cohort.

Allelic frequency of 12-FGF4RG and the association between the genotype with number of calcified intervertebral discs visible on radiographs in Coton de Tuléar and French Bulldog breeds

BACKGROUND

Intervertebral disc disease (IVDD) is a major welfare issue in chondrodystrophic dogs. It is a consequence of chondroid metaplasia of the nucleus pulposus, leading to premature degeneration and calcification of the intervertebral discs (IVDs). Radiographic grading based on the number of calcified discs visible on radiograph (CDVR) between the ages of 24-48 months is an established method for selective breeding against IVDD in dogs. Premature IVD degeneration has a genetic background, and a FGF4 retrogene insertion on chromosome 12 (12-FGF4RG) has been shown to be involved. The aim of this study was to determine the 12-FGF4RG allele frequency and genotype proportions, and the influence of the 12-FGF4RG genotype on number of CDVR in a study population of young adult Coton de Tuléars and French Bulldogs. In this combined prospective and retrospective analytical study, we investigated dogs radiographically screened at 24-48 months of age. The first dataset consisted of 12-FGF4RG genotyping results of 465 Coton de Tuléars and intervertebral disc calcification (IDC) grading results (no, mild, moderate, or severe) for 222 of them. The second dataset included 12-FGF4RG genotypes and IDC grading results (no or severe) of 81 French Bulldogs.

RESULTS

We observed 12-FGF4RG homozygous, heterozygous and wildtype individuals in both studied breeds. The 12-FGF4RG allele frequencies were also lower than previously reported in the studied breeds and Coton de Tuléars had lower allele frequency (0.35) than French Bulldogs (0.85). The distribution of IDC grading results were 59% no, 16% mild, 9% moderate and 16% severe in Coton de Tuléars and 59% no and 41% severe in French Bulldogs. In both breeds, every copy of the 12-FGF4RG allele significantly increased the risk for a higher number of CDVR, indicating incomplete dominance.

CONCLUSIONS

Our results confirm the significant association between the 12-FGF4RG allele and the number of CDVR and IDC grade in two different chondrodystrophic breeds in age-controlled cohorts of young adult dogs. Our results also suggest that radiographic screening of CDVR and genetic testing of 12-FGF4RG could be used to breed against IVD degeneration predisposing to IVDD.

Walking Slope and Heavy Backpacks Affect Peak and Impulsive Lumbar Joint Contact Forces

Heavy load carriage is associated with musculoskeletal overuse injury, particularly in the lumbar spine. In addition, steep walking slopes and heavy backpacks separately require adaptation of torso kinematics, but the combined effect of sloped walking and heavy backpack loads on lumbar joint contact forces is unclear. Backpacks with hip belt attachments can reduce pressure under the shoulder straps; however, it is unknown if wearing a hip belt reduces lumbar spine forces. We used a musculoskeletal modeling and simulation approach to quantify peak and impulsive L1L2 and L4L5 lumbar joint contact forces in the anterior/posterior shear and compressive directions during walking on 0 deg and ±10 deg slopes, with no backpack and with 40% body weight backpack load using two different backpack configurations (hip belt assisted and shoulder-borne). Both walking slope and backpack load significantly affected shear and compressive peak and impulsive forces. The largest peak shear and compressive forces of 1.57 and 5.23 body weights, respectively, exceed recommended limits and were observed during uphill walking with shoulder-borne loads. However, only impulsive force results revealed differences due to the backpack configuration, and this effect depended on walking slope. During downhill walking only, the hip belt-assisted configuration resulted compressive impulses lower than during shoulder borne by 0.25 body weight seconds for both L1L2 and L4L5. These results indicate that walking uphill with heavy loads causes high shear and compressive lumbar forces that may increase overuse injury risk. In addition, our results suggest it is especially important to wear a hip belt when walking downhill.

Defining a Critical Partition Zone for Sagittal Alignment in Lumbar Spine Fusion Surgery: A Systematic Review

BACKGROUND

Sagittal alignment in the lumbar spine is essential for spinal stability and functionality, with significant implications in surgical planning for spinal deformity correction. However, standardized lumbar partitioning, particularly identifying a critical sagittal alignment zone, remains underdefined. This study aims to establish a reliable lumbar partition to guide surgical decisions and optimize clinical outcomes.

METHODS

A systematic review of four major biomedical databases yielded 32 studies, of which 4 met the inclusion criteria. Studies on asymptomatic adults with segmental lordosis data stratified by pelvic incidence were analyzed. Lumbar lordosis values were converted to percentages, allowing for cross-study comparison. Sensitivity analysis and bias assessment were performed to ensure methodological rigor.

RESULTS

The findings identified the L3-L5 interval, especially around the L4 vertebra, as a critical biomechanical zone across various populations and pelvic incidence groups. Individuals with higher pelvic incidence had concentrated lordosis in lower segments, while those with lower pelvic incidence had greater lordosis in upper segments, underscoring the L3-L5 region's stability as a surgical reference.

CONCLUSIONS

The L3-L5 interval serves as a key partition zone for sagittal alignment, providing a stable reference for lumbar spine fusion. These findings offer a foundational clinical reference, potentially improving alignment outcomes and reducing postoperative complications.

Effect of Different Injury Morphology of the Endplate on Intervertebral Disc Degeneration: Retrospective Cohort Study

OBJECTIVES

To describe a simplified classification scheme for endplate injury morphology based on 3D CT and to examine possible associations between endplate injury morphology and vertebral space and other variables such as type of fracture and disc degeneration in a group of patients with thoracolumbar fractures.

METHODS

This study was a retrospective cohort study. We collected patients with thoracolumbar fractures admitted from January 2015 to August 2020 and divided them into three groups based on the morphology of endplate injury (45 cases of mild endplate injury, 54 cases of moderate endplate injury, and 42 cases of severe endplate injury, SEI). Data of vertebral body and intervertebral space height and angle, the Pfirrmann grade, endplate healing morphology were collected during preoperative, postoperative, and long-term follow-up of patients in each group. One-way analysis of variance (ANOVA), chi-squared test, and repeated measurement ANOVA were used to compare and analyze the influence of endplate injury morphology on patient prognosis.

RESULTS

Most moderate injuries to the endplate (fissure-type injury) and severe injuries (irregular depression-type injury, Schmorl's node-type injury) resulted in significant disc degeneration in the long-term transition. This study also showed significant differences in the height of the anterior margin of the injured spine and the intervertebral space height index during this process.

CONCLUSIONS

The current study suggests that although the region of injury in endplate fissure-type injury is small preoperatively, it may be a major factor in leading to severe disc degeneration, loss of intervertebral height, and Cobb angle in the long term. The results of our study therefore may allow surgeons to predict the prognosis of patients with thoracolumbar fractures and guide their treatment.

SymTC: A symbiotic Transformer-CNN net for instance segmentation of lumbar spine MRI

Intervertebral disc disease, a prevalent ailment, frequently leads to intermittent or persistent low back pain, and diagnosing and assessing of this disease rely on accurate measurement of vertebral bone and intervertebral disc geometries from lumbar MR images. Deep neural network (DNN) models may assist clinicians with more efficient image segmentation of individual instances (discs and vertebrae) of the lumbar spine in an automated way, which is termed as instance image segmentation. In this work, we proposed SymTC, an innovative lumbar spine MR image segmentation model that combines the strengths of Transformer and Convolutional Neural Network (CNN). Specifically, we designed a parallel dual-path architecture to merge CNN layers and Transformer layers, and we integrated a novel position embedding into the self-attention module of Transformer, enhancing the utilization of positional information for more accurate segmentation. To further improve model performance, we introduced a new data synthesis technique to create synthetic yet realistic MR image dataset, named SSMSpine, which is made publicly available. We evaluated our SymTC and the other 16 representative image segmentation models on our private in-house dataset and public SSMSpine dataset, using two metrics, Dice Similarity Coefficient and the 95th percentile Hausdorff Distance. The results indicate that SymTC surpasses the other 16 methods, achieving the highest dice score of 96.169 % for segmenting vertebral bones and intervertebral discs on the SSMSpine dataset. The SymTC code and SSMSpine dataset are publicly available at https://github.com/jiasongchen/SymTC.

A correlation study of preoperative lumbar paraspinal muscle quality and L5-S1 lumbar foraminal stenosis degeneration after L4-5 TLIF

STUDY DESIGN

This was a retrospective study.

OBJECTIVES

Adjacent segment degeneration (ASD) is a major complication associated with spinal fusion. The lumbar paraspinal muscle is an essential factor influencing the occurrence of ASD. This study aimed to investigate the effect of preoperative lumbar paraspinal muscle quality on L5-S1 adjacent lumbar foraminal stenosis degeneration (ASLFSD) after L4-5 transforaminal lumbar interbody fusion (TLIF).

METHODS

A total of 113 patients diagnosed with lumbar spinal stenosis at L4-5 were treated with TLIF. Lumbar paraspinal muscle measurements were obtained preoperatively and bilaterally from axial T2-weighted MR images. The measurements included the total cross-sectional area of psoas (PS-tCSA), of erector spinae (ES-tCSA), and of multifidus (MF-tCSA); and fatty infiltration of psoas (PS-FI), of erector spinae (ES-FI), and of multifidus (MF-FI). Foraminal measurements, including posterior disc height (PDH), disc-to-facet distance (D-F), foraminal height (FH), and foraminal area (FA), were obtained bilaterally using a computed tomography system. The association between lumbar paraspinal muscle quality and changes in foraminal measurements was also studied.

RESULTS

We observed that the FH and FA significantly reduced at 1 year postoperatively at the mean follow-up period of 41.56 ± 8.38 months (range, 43-50 months), and PDH, D-F, FH, and FA all significantly reduced at final follow-up. These changes in foraminal measurements were significantly and negatively correlated with PS-FI, ES-FI, and MF-FI.

CONCLUSION

During the clinical follow-up, we found that patients with a higher degree of paraspinal muscle FI were more likely to develop L5-S1 ASLFSD after L4-5 TLIF.

10-year Longitudinal MRI Study of Intervertebral Disk Degeneration in Patients With Lumbar Spinal Canal Stenosis After Posterior Lumbar Decompression Surgery

STUDY DESIGN

A prospective longitudinal magnetic resonance imaging (MRI) study.

OBJECTIVE

The objective of this study was to describe the progression of intervertebral disk (IVD) degeneration in patients who underwent posterior decompression surgery for lumbar spinal canal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

IVD degeneration contributes to the pathogenesis of LSS; however, the long-term consequences of degenerative changes after decompression surgery remain unknown.

MATERIALS AND METHODS

Of 258 consecutive patients who underwent posterior lumbar decompression surgery for LSS, 62 who underwent MRI at their 10-year follow-up were included; 17 age-matched asymptomatic volunteers were analyzed as controls. Three MRI findings representing IVD degeneration were graded on their severity: decrease in signal intensity, posterior disk protrusion (PDP), and disk space narrowing (DSN). Clinical outcome was assessed using the low back pain (LBP) score from the Japanese Orthopaedic Association scoring system. We examined the association between the progression of degenerative changes on MRI and LBP/associated factors using logistic regression adjusting for age at baseline and sex.

RESULTS

The severity of IVD degeneration tended to be higher in patients with LSS than asymptomatic volunteers at both baseline and follow-up. IVD degeneration progressed in all patients during the 10-year follow-up period. Progression of decrease in signal intensity and PDP was observed at L1/2 in 73% and at L2/3 in 34%, respectively (the highest frequencies in the lumbar spine). Progression of DSN was highest at L4/5 in 42%. The rates of PDP and DSN progression during the 10-year follow-up period tended to be greater in patients with LSS than in asymptomatic volunteers. No significant difference in the proportion of LBP deterioration was evident for individuals with and without MRI findings of progression.

CONCLUSIONS

Our study reveals a natural history of the long-term postoperative course of IVD degeneration after posterior decompression surgery for LSS. Compared with healthy controls, patients with LSS seemed to be predisposed to IVD degeneration. Lumbar decompression surgery may promote the progression of DSN; however, progression of IVD degeneration after lumbar decompression surgery was not associated with worsening LBP scores.

Evaluation of long-term clinical outcomes and the incidence of adjacent proximal segment degenerative disease with algorithmic transforaminal interbody fusion: A multicenter prospective study

Study Design

This was a prospective multicenter study.

Background

Adjacent segment degenerative disease (ASDd) is a common complication of open transforaminal lumbar interbody fusion (O-TLIF), the leading cause of which is initial adjacent segment degeneration (ASD). To date, various surgical techniques for the prevention of ASDd have been developed, such as, simultaneous use of interspinous stabilization (IS) and preventive rigid stabilization of the adjacent segment. The use of these technologies is often based on the subjective opinion of the operating surgeon, or on the assessment of one of the predictors of ASDd. Only sporadic studies are devoted to a comprehensive study of risk factors of ASDd development and personalized performance of O-TLIF.

Purpose

The purpose of this study was to evaluate long-term clinical outcomes and the incidence of degenerative disease of the adjacent proximal segment using clinical-instrumental algorithm for preoperative planning to O-TLIF.

Materials and Methods

The prospective, nonrandomized, multicenter cohort study included 351 patients who underwent primary O-TLIF, and the adjacent proximal segment had initial ASD. Two cohorts were identified. The prospective cohort included 186 patients who were operated by using the algorithm of personalized O-TLIF performance. The control retrospective cohort consisted of patients (n = 165), from our own database who had been operated on previously without the algorithmized approach. Treatment outcomes were analyzed by Visual Analog Scale (VAS) assessment of pain syndrome, Oswestry Disability Index (ODI) scores, physical component score (PCS) and mental component score (MCS) scores of the Short Form 36 questionnaire, frequency of ASDd was compared between studied cohorts.

Results

Thirty-six months after follow-up, the prospective cohort had better SF36 MCS/PCS outcomes, less disability according to ODI, and lower pain level according to VAS (P < 0.05). The incidence of ASDd in the prospective cohort was 4.9%, which was significantly lower than in the retrospective cohort (9%).

Conclusions

The prospective use of a clinical-instrumental algorithm for preoperative planning of rigid stabilization, depending on the biometric parameters of the proximal adjacent segment, significantly reduced the incidence of ASDd and improved long-term clinical outcomes compared with the retrospective group.

Lumbar stenosis due to wild-type transthyretin amyloid-induced thickening of the ligamentum flavum: a separate etiology from degeneration of intervertebral discs?

OBJECTIVE

Wild-type transthyretin amyloid (ATTRwt) is deposited in the ligamentum flavum (LF) of a subset of patients with spinal stenosis who undergo decompressive surgery, although its role in the pathophysiology of spinal stenosis is unknown. It has been theorized that degeneration of intervertebral discs causes increased mechanical stress and inflammatory/degenerative cascades and ultimately leads to LF fibrosis. If ATTRwt deposits contribute to LF thickening and spinal stenosis through a different pathway, then patients with ATTRwt may have less severe disc degeneration than those without it. In this study, the authors compared the severity of disc degeneration between patients with lumbar stenosis with and without amyloid in their LF to test whether ATTRwt is a unique contributor to LF thickening and spinal stenosis.

METHODS

Of 324 consecutive patients between 2018 and 2019 who underwent decompression surgery for spinal stenosis and had LF samples sent for pathological analysis, 31 harboring ATTRwt were compared with 88 controls. Patient medical records were retrospectively reviewed for demographic and surgical information. Disc degeneration was assessed on preoperative T2-weighted MR images with the modified Pfirrmann grading system at every lumbar disc level.

RESULTS

Baseline characteristics were similar between the groups, except for a statistically significant increase in age in the ATTRwt group. The crude unadjusted comparisons between the groups trended toward a less severe disc degeneration in the ATTRwt group, although this difference was not statistically significant. A multivariable linear mixed-effects model was created to adjust for the effects of age and to isolate the influence of ATTRwt, the presence of an operation at the level, and the specific disc level (between L1 and S1). This model revealed that ATTRwt, the presence of an operation, and the specific level each had significant effects on modified Pfirrmann scores.

CONCLUSIONS

Less severe disc degeneration was noted in patients with degenerative spinal stenosis harboring ATTRwt compared with those without amyloid. This finding suggests that ATTRwt deposition may play a separate role in LF thickening from that played by disc degeneration. Future studies should aim to elucidate this potentially novel pathophysiological pathway, which may uncover an exciting potential for the development of amyloid-targeted therapies that may help slow the development of spinal stenosis.

Relationship between the morphology and composition of the lumbar paraspinal and psoas muscles and lumbar intervertebral motion in people with chronic low back pain

Muscles of the lumbar spine play an important role in controlling segmental intervertebral motion. This study aimed to evaluate the association between lumbar intervertebral motion and changes in lumbar morphology/composition in people with chronic low back pain (CLBP). A sample of 183 patients with CLBP participated in this cross-sectional study. Participants underwent lumbar flexion-extension X-Rays to determine vertebral motion (translational and/or rotational motion) of lumbar levels (L1-L2 to L5-S1) and lumbar spine Magnetic Resonance Imaging (MRI) to quantify total and functional cross-sectional areas (CSAs) and asymmetry of the multifidus, lumbar erector spinae and psoas muscles. The relationship between morphology/composition of the muscles and lumbar intervertebral motion was investigated. Smaller total and functional CSAs of the multifidus and greater CSAs of the lumbar erector spinae muscle were observed in participants with greater intervertebral motion. Muscle asymmetry was observed at different lumbar vertebral levels. The greatest amount of translational intervertebral motion was observed at the L3-L4 level, while the greatest amount of rotational translation occurred at the L4-5 level. Associations were observed between the morphology of the paraspinal muscles at the vertebral levels adjacent to the L3-L4 level and the increased intervertebral motion at this level. Relationships between measures of muscle morphology/composition and increased segmental vertebral motion were observed. The results may provide a plausible biological reason for the effectiveness of rehabilitating deficient paraspinal muscles in a subset of people with CLBP. This article is protected by copyright. All rights reserved.

Regional Homogeneity in Patients With Mild Cognitive Impairment: A Resting-State Functional Magnetic Resonance Imaging Study

Objective

To analyze the potential changes in brain neural networks in resting state functional magnetic resonance imaging (rs-fMRI) scans by regional homogeneity (ReHo) in patients with mild cognitive impairment (MCI).

Methods

We recruited and selected 24 volunteers, including 12 patients (6 men and 6 women) with MCI and 12 healthy controls matched by age, sex, and lifestyle. All subjects were examined with rs-fMRI to evaluate changes in neural network connectivity, and the data were analyzed by ReHo method. Correlation analysis was used to investigate the relationship between ReHo values and clinical features in different brain regions of MCI patients. The severity of MCI was determined by the Mini-Mental State Examination (MMSE) scale.

Results

The signals of the right cerebellum areas 4 and 5, left superior temporal, right superior temporal, left fusiform, and left orbital middle frontal gyri in the patient group were significantly higher than those in the normal group (P < 0.01 by t-test of paired samples). The signal intensity of the right inferior temporal and left inferior temporal gyri was significantly lower than that of the normal group (P < 0.01). The ReHO value for the left inferior temporal gyrus correlated negatively with disease duration, and the value for the right inferior temporal gyrus correlated positively with MMSE scores.

Conclusion

Mild cognitive impairment in patients with pre- Alzheimer's disease may be related to the excitation and inhibition of neural networks in these regions. This may have a certain guiding significance for clinical diagnosis.