Multifidus Muscles Lipid Content Is Associated with Intervertebral Disc Degeneration: A Quantitative Magnetic Resonance Imaging Study

Understanding the Interplay Between Paraspinal Muscle Atrophy and Lumbar Endplate Degeneration: A 3-Year Longitudinal Study

STUDY DESIGN

Retrospective analysis of longitudinal data.

OBJECTIVE

To assess the association between the paraspinal musculature (PM) and lumbar endplate degeneration.

BACKGROUND

The PM is essential for spinal stability, while the vertebral endplate is pivotal for nutrient transport and force distribution. The clinical importance of both has been highlighted in recent literature, though little is known about their interaction.

METHODS

We identified patients with lumbar MRI scans due to low back pain, with a 3-year interval between MRI scans. Endplate damage was assessed by the total endplate score (TEPS) at each lumbar level. The PM was evaluated for its functional cross-sectional area and fatty infiltration (FI) at the L4 level. We used a generalized mixed model to analyze the association between PM parameters and TEPS at timepoint one, adjusting for age, sex, BMI, diabetes, hypertension, and smoking status. The association with the progression of endplate damage was analyzed through an ordinal regression model, additionally adjusted for TEPS at baseline.

RESULTS

In all, 329 patients were included, with a median follow-up time of 3.4 years. Participants had a median age of 59 and a BMI of 25.8 kg/m 2 . In the univariate analysis, FI of the posterior PM was significantly associated with TEPS at baseline (β: 0.08, P <0.001) and progression of TEPS [Odds Ratio (OR): 1.03, P =0.020] after adjustment for confounders. The β and OR in this analysis are per percent of FI. In a binary analysis, patients with FI≥40% had an OR of 1.92 ( P =0.006) for the progression of TEPS.

CONCLUSIONS

This is the first longitudinal study assessing the relationship between PM and endplate degeneration, demonstrating the association between PM atrophy and the progression of endplate degeneration. This insight may aid in identifying patients at risk for degenerative lumbar conditions and guide research into preventive measures.

Associations between visceral fat chronic low back pain and central sensitization in patients with lumbar spinal stenosis

BACKGROUND

Pain sensitization may be one of the mechanisms contributing to chronic low back pain (CLBP).

OBJECTIVE

To evaluate the association between visceral fat, CLBP, and central sensitization (CS); describe the relationship between low back pain (LBP) intensity and CS; and identify possible correlation between visceral fat and LBP intensity.

METHODS

Patients with CLBP were divided using their CS inventory (CSI) scores into low- (CSI < 40) and high-CSI (CSI ⩾ 40) subgroups. We compared computed tomography (CT) measurements and scores for association with pain according to the visual analogue scale (VAS) between the two groups.

RESULTS

The low-CSI and the high-CSI groups had 47 patients (67.1%; 21 men, 26 women) and 23 patients (32.9%; 11 men and 12 women), respectively. The high-CSI group had a significantly higher mean VAS score (p< 0.01) and estimated mean visceral fat area (p< 0.05) than the low-CSI group. There was a moderate positive correlation between VAS score and visceral fat (standardised partial regression coefficient: 0.659, p< 0.01) in the high-CSI group according to multiple linear regression analysis adjusted for age and sex.

CONCLUSIONS

Visceral fat is associated with CLBP, regardless of sex or age, and may be a potential therapeutic target for CLBP with CS.

Spinal degeneration is associated with lumbar multifidus morphology in secondary care patients with low back or leg pain

Associations between multifidus muscle morphology and degenerative pathologies have been implied in patients with non-specific low back pain, but it is unknown how these are influenced by pathology severity, number, or distribution. MRI measures of pure multifidus muscle cross-sectional area (CSA) were acquired from 522 patients presenting with low back and/or leg symptoms in an outpatient clinic. We explored cross-sectional associations between the presence, distribution, and/or severity of lumbar degenerative pathologies (individually and in aggregate) and muscle outcomes in multivariable analyses (beta coefficients [95% CI]). We identified associations between lower pure multifidus muscle CSA and disc degeneration (at two or more levels): − 4.51 [− 6.72; − 2.3], Modic 2 changes: − 4.06 [− 6.09; − 2.04], endplate defects: − 2.74 [− 4.58; − 0.91], facet arthrosis: − 4.02 [− 6.26; − 1.78], disc herniations: − 3.66 [− 5.8; − 1.52], and when > 5 pathologies were present: − 6.77 [− 9.76; − 3.77], with the last supporting a potential dose–response relationship between number of spinal pathologies and multifidus morphology. Our findings could hypothetically indicate that these spinal and muscle findings: (1) are part of the same degenerative process, (2) result from prior injury or other common antecedent events, or (3) have a directional relationship. Future longitudinal studies are needed to further examine the complex nature of these relationships.

Factors associated with low back pain in patients with lumbar spinal stenosis: a cross-sectional study

BACKGROUND

Low back pain (LBP) is a major symptom of symptomatic lumbar spinal stenosis (SLSS). It is important to assess LBP in patients with SLSS to develop better treatment. This study aimed to analyse the factors associated with LBP in patients with SLSS.

METHODS

This cross-sectional study included consecutive patients with SLSS aged between 51 and 79 years who had symptoms in one or both the legs, with and without LBP. The participants were classified into two groups: the high group (LBP visual analogue scale [VAS] score ≥ 30 mm) and the low group (LBP VAS score < 30 mm). We performed multiple logistic regression analysis with the high and low groups as dependent variables, and a receiver operating characteristic (ROC) analysis.

RESULTS

A total of 80 patients with LSS were included (35 men and 45 women; mean age 64.5 years), with 47 and 30 patients in the high and low groups, respectively. Multivariate logistic regression analysis revealed that the sagittal vertical axis (SVA; + 10 mm; odds ratio, 1.331; 95% confidence interval, 1.051 - 1.660) and pelvic incidence-lumbar lordosis (PI-LL; + 1°; odds ratio, 1.065; 95% confidence interval, 1.019-1.168) were significantly associated with LBP. A receiver operating characteristic analysis revealed cut-off values of 47.0 mm of SVA and 30.5° of PI-LL, respectively.

CONCLUSION

Our results indicated that SVA and PI-LL were significant predictors for LBP in SLSS. It is suggested that these parameters should be taken into consideration when assessing LBP in patients with SLSS.

Imaging Evaluation of Fat Infiltration in Paraspinal Muscles on MRI: A Systematic Review with a Focus on Methodology

Purpose

Numerous studies have applied a variety of methods to assess paraspinal muscle degeneration. However, the methodological differences in imaging evaluation may lead to imprecise or inconsistent results. This article aimed to provide a pragmatic summary review of the current imaging modalities, measurement protocols, and imaging parameters in the evaluation of paraspinal muscle fat infiltration (FI) in MRI studies.

Methods

Web of Science, EMBASE, and PubMed were searched from January 2005 to March 2020 to identify studies that examined the FI of paraspinal muscles on MRI among patients with lumbar degenerative diseases.

Results

Intramyocellular lipids measured by magnetic resonance spectroscopy and FI measured by chemical‐shift MRI were both correlated to low back pain and several degenerative lumbar diseases, whereas results on the relationship between FI and degenerative lumbar pathologies using conventional MRI were conflicting. Multi‐segment measurement of FI at the lesion segment and adjacent segments could be a prognostic indicator for lumbar surgery. Most studies adopted the center of the intervertebral disc or endplate as the level of slice to evaluate the FI. Compared with visual semiquantitative assessment, quantitative parameters appeared to be precise for eliminating individual or modality differences. It has been demonstrated that fat CSA/total CSA (based on area) and muscle–fat index (based on signal intensity) as quantitative FI parameters are associated with multiple lumbar diseases and clinical outcomes after surgery.

Conclusion

Having a good command of the methodology of paraspinal muscle FI on MRI was effective for diagnosis and prognosis in clinical practice.

Association between lumbar segmental mobility and intervertebral disc degeneration quantified by magnetic resonance imaging T2 mapping

Background

The relation between segmental mobility and degree of lumbar degenerative change is still unknown. This cross-sectional study aimed to elucidate the association between intervertebral disc degeneration (IVDD) and segmental mobility in chronic low back pain using magnetic resonance imaging (MRI) T2 mapping.

Methods

Subjects comprised 60 patients (29 men, 31 women; mean age, 61.8 ± 1.9 years; range, 41–79 years). T2 values of the anterior annulus fibrosus (AF), the nucleus pulposus (NP) and the posterior AF were evaluated with MRI T2 mapping. Facet joint degeneration was divided into 4 grades using MRI. We analyzed the correlation between segmental mobility and T2 values of anterior AF, NP and posterior AF using multiple linear regression analysis adjusted for age and facet joint degeneration.

Results

The standardized partial regression coefficient of the anterior AF, NP and posterior AF T2 values were 0.125 (p=0.72), 0.499 (p<0.01) and –0.026 (p=0.11), respectively, for the L1-2 level; 0.102 (p=0.27), 0.395 (p<0.01) and –0.094 (p=0.20), respectively, for the L2-3 level; 0.108 (p=0.38), 0.415 (p<0.01) and –0.050 (p=0.51), respectively, for the L3-4 level; 0.124 (p=0.09), 0.396 (p<0.01) and 0.025 (p=0.73), respectively, for the L4-5 level; and 0.011 (p=0.89), 0.443 (p<0.01) and 0.030 (p=0.72), respectively, for the L5-S level. There was a significantly positive correlation between segmental mobility and the T2 values of NP at L1–L2, L2–L3, L3–L4, L4–L5, and L5–S1. No significant correlations arose between segmental mobility and the T2 values of the anterior AF and the posterior AF at L1–L2, L2–L3, L3–L4, L4–L5, and L5–S1.

Conclusion

Characterization of the relationship between NP degeneration and lumbar segmental mobility may enhance our ability to evaluate the changes seen in kinematics of functional spinal unit.

Magnetic Resonance Spectroscopic Analysis of Multifidus Muscle Lipid Contents and Association with Nociceptive Pain in Chronic Low Back Pain

Study Design

Cross-sectional study.

Purpose

This study aimed to analyze the differences in the lipid contents in chronic low back pain (CLBP) patients with nociceptive pain (NocP) and neuropathic pain (NeP) using magnetic resonance spectroscopy (MRS) of the multifidus muscle (Mm).

Overview of Literature

Early identification of the pain characteristics with CLBP is important because specific treatment approaches are required, depending on NocP and NeP.

Methods

The participants were 50 patients with CLBP (23 men and 27 women; mean age, 63.1±17.8 years; range, 41–79 years). We compared the Visual Analog Scale (VAS) scores, intramyocellular lipids (IMCLs) and extramyocellular lipids (EMCLs) of the Mm in NocP and NeP groups, as evaluated with the Japanese NeP screening questionnaire.

Results

The patients were categorized into the NocP (n=32) and NeP (n=18) groups. The mean VAS score of the NocP group was 59.3±3.1 mm and that of the NeP group was 73.6±4.6 mm. The mean VAS score was significantly higher in the NeP group as compared to that in the NocP group (p<0.01). As per the analysis of covariance for the VAS score, the mean IMCL levels of the Mm in the NocP and NeP groups were 722.3 mmol/L (95% confidence interval [CI], 611.4–833.1) and 484.8 mmol/L (95% CI, 381.1–588.5), respectively. The mean IMCL level was significantly higher in the NocP group than in the NeP group (p<0.05). The mean EMCL levels of the Mm for the NocP and NeP groups were 6,022.9 mmol/L (95% CI, 4,510.6–7,535.2) and 5,558.1 mmol/L (95% CI, 4,298.3–6,817.9), respectively; however, the difference was not significant (p=0.72).

Conclusions

The results indicated an association between the IMCL level of the Mm and NocP. Our results suggest that MRS of the Mm might be beneficial for the assessment of CLBP as well as appropriate targeted analgesic therapies.

Is the Lipid Content of the Psoas Major Correlated with Chronic Low Back Pain and Spinopelvic Alignment? A Magnetic Resonance Spectroscopic Study

Study Design

Cross-sectional observational study.

Purpose

This study aimed to analyze any potential associations of extramyocellular lipid (EMCL) and intramyocellular lipid (IMCL) contents with (1) the intensity of low back pain (LBP); (2) age, cross-sectional area (CSA), and fatty infiltration (FI) of the psoas major; and (3) spinopelvic parameters.

Overview of Literature

The psoas major has clinically relevant function; however, the association of this muscle with chronic LBP is controversial. Magnetic resonance spectroscopy enables a detailed analysis of the composition of muscular fat tissues such as its EMCL and IMCL contents.

Methods

The study population comprised 40 patients (19 males, 21 females; mean age, 61.7±2.4 years). Possible correlations of LBP Visual Analog Scale (VAS) scores, age, CSA, FI, and spinopelvic parameters with EMCL and IMCL contents of the psoas major were assessed.

Results

No association was identified between the EMCL and IMCL contents and LBP VAS scores (r=0.05, p=0.79 and r=0.06, p=0.75, respectively). The EMCL content correlated with age (r=0.47, p<0.01), body mass index (BMI) (r=0.44, p<0.01), CSA (r=−0.59, p<0.01), and FI (r=0.49, p<0.01). EMCL content showed a significant negative correlation with sacral slope (SS) (r=−0.43, p<0.05) and positive correlation with pelvic tilt (PT) (r=0.56, p<0.01).

Conclusions

EMCL content correlated with age, BMI, CSA, and FI of the psoas major, while IMCL content had no correlation. This study found correlations between SS and PT and EMCL content of the psoas major, but no correlations were found between spinopelvic parameters and IMCL content of the psoas major.

Imaging diagnosis for intervertebral disc

Various functional magnetic resonance imaging (MRI) techniques have been investigated in recent years and are being used in clinical practice for the patients with low back pain (LBP). MRI is an important modality for diagnosing intervertebral disc (IVD) degeneration. In recent years, there have been several reported attempts to use MRI T2 mapping and MRI T1ρ mapping to quantify lumbar disc degeneration. MRI T2 mapping involves digitizing water content, proteoglycan content, and collagen sequence breakdown as relaxation times (T2 values) at each site. These digitized values are used to create a map, that is, then used to quantitatively evaluate the metabolite concentrations within IVD tissues. MRI T2 mapping utilizes the T2 relaxation time to quantify moisture content and the collagen sequence breakdown. MRI T1ρ mapping digitizes water molecule dispersion within the cartilaginous matrix to evaluate the degree of cartilaginous degeneration. Magnetic resonance spectroscopy is a less-invasive diagnostic test that provides biochemical information. Adequate analysis of the IVD has not yet been performed, although there are indications of a relationship between the adipose content of the multifidus muscle in the low back and LBP. The ultra short TE technique has been recently used to investigate lumbar cartilaginous endplates. Unlike diagnosis based on contrast-enhanced images of the IVD, which depends on the recurrence of pain that is determined subjectively, MRI-based diagnosis is less-invasive and based on objective imaging findings. It is therefore expected to play a key role in the diagnostic imaging of IVD conditions in the future.