Effect of race, age, and gender on lumbar muscle volume and fat infiltration in the degenerative spine

Fatty Infiltration of Muscles Influences Short-term Walking Speed after Primary Total Hip Arthroplasty

Objectives

This study aimed to determine the relationship between preoperative fatty infiltration of the lower extremity muscles and walking speed at 2 weeks after total hip arthroplasty (THA).

Methods

This was a single-institution retrospective cohort study. Participants in this study were patients undergoing primary THA. Fatty infiltration in each muscle (bilateral psoas major, gluteus maximus, gluteus medius, gluteus minimus, quadriceps, and triceps surae) was assessed using non-contrast X-ray computed tomography images obtained during a detailed preoperative examination. The outcome of this study was the normal comfortable walking speed at 2 weeks after THA. Decreased walking speed was defined as less than 0.8 m/s (non-decreased group, coded 0; decreased group, coded 1). Multivariate logistic regression analysis was used to analyze the relationship between fatty infiltration of each skeletal muscle and walking speed.

Results

A total of 168 participants were included in the analysis. On the operative side, the analysis identified fatty infiltration of the gluteus medius (odds ratio, 0.95; 95% confidence interval, 0.91-0.99) as a determinant of decreased walking speed after THA. On the nonoperative side, the analysis identified fatty infiltration of the quadriceps (odds ratio, 0.91; 95% confidence interval, 0.83-0.99) as a determinant of decreased walking speed after THA.

Conclusions

In patients undergoing THA, increased fatty infiltration of the gluteus medius on the operative side and the quadriceps on the nonoperative side were associated with decreased walking speed at 2 weeks postoperatively.

Intermuscular adipose tissue affected muscle density more than intramuscular adipose tissue content with opportunistic screening at abdominal CT

This study aimed to determine whether intermuscular adipose tissue (IMAT) or intramuscular adipose tissue content (IMAC) has a greater effect on skeletal muscle density (SMD) and to explore the underlying mechanisms. We recruited 292 inpatients without musculoskeletal system disease, all of whom underwent abdominal CT. Muscle parameters, including skeletal muscle area (SMA), skeletal muscle index (SMI), SMD, IMAC, and IMAT, as well as fat parameters-subcutaneous fat area (SFA) and subcutaneous fat density (SFD) in the abdominal wall-were measured by two musculoskeletal radiologists using ImageJ software at the third lumbar vertebra (L3) level. One-way ANOVA with LSD (chi-square test for group comparisons where p > 0.05) or Dunnett's T3 test (p < 0.05) was employed to compare muscle parameters between genders and across age groups. The relationship between SMD and muscle measurements was analyzed using Spearman's correlation coefficient. Multiple regression analysis identified and compared factors influencing SMD. SMD was highly correlated with IMAT and IMAC (p < 0.05), moderately correlated with gender, age, and SFA (p < 0.05). Multiple linear regression analysis indicated that IMAC, IMAT, and age significantly affected SMD (p < 0.05), with the order of influence being IMAT (β = -0.616), IMAC (β = -0.429), and age (β = -0.098). SFA and gender did not significantly affect SMD (p > 0.05). The findings revealed that age, IMAT, and IMAC influence SMD, with IMAT exerting the most significant impact.

Sex-specific asymmetry in lumbar paraspinal muscles among chronic low back pain patients: correlation with pain duration and intensity

Chronic low back pain (cLBP) is a multifactorial condition, including paraspinal muscle asymmetry. Understanding the relationship between muscle asymmetry and cLBP and how this varies by sex is crucial for targeted interventions. From January 2022 to December 2023, 250 participants were enrolled: 117 without back pain (no-BP) (61 females, 56 males) and 133 with cLBP (69 females, 64 males). MRI assessed the cross-sectional area (CSA), functional CSA (FCSA), and fat infiltration (FI) of the paraspinal muscles, including the psoas major (PM), quadratus lumborum (QL), erector spinae (ES), and multifidus (MF), at all lumbar levels. Asymmetry indices were calculated for CSA (CAI), FCSA (FCAI), and FI (FIAI). Data were analyzed using multiple linear and logistic regression. Muscle asymmetries were observed in both sexes and groups, with significant differences in the CSA and FCSA of the QL in males and notable FI asymmetries in the cLBP group. In women with cLBP, higher ES CAI and FCAI at L5/S1 (p < 0.05) and lower PM FCAI at L4/5 (OR 0.869, 95% CI 1.008-1.150, p = 0.03) were observed. FIAI was significantly higher in cLBP for ES at L2/3 and PM, MF, and ES at L4/5 (p < 0.05). Men with cLBP had lower PM CAI and FCAI at L1/2 and L4/5 (p < 0.05), with varying FIAI levels. FIAI correlated with cLBP duration and intensity in both sexes (p < 0.05). Paraspinal muscle asymmetry, particularly in fat infiltration, is associated with cLBP and varies by sex. These findings support sex-specific approaches to managing cLBP.

A novel T2-weighted series-based modified vertebral bone quality score for evaluating bone mineral density

OBJECTIVE

To evaluate the modified vertebral bone quality (VBQ) method on the magnetic resonance imaging (MRI) T1-weighted (T1w), T2-weighted (T2w), and fat suppression (FS) series in evaluating bone mineral density (BMD) for patients with degenerative lumbar disease.

METHODS

We reviewed preoperative data of postmenopausal female patients aged ≥ 50 years hospitalized to undergo lumbar surgery for degenerative lumbar disease with available MRI and dual-energy X-ray absorptiometry (DEXA). Patients were categorized into three groups according to T-score. The VBQCSF score was calculated as the L1-L4 median signal intensity (SI) divided by the L3 CSF SI. One-way analysis of variance was applied to assess the discrepancy between groups. The diagnostic performance of VBQ scores for distinguishing low BMD was analyzed using receiver operating characteristic (ROC) analysis.

RESULTS

The study included 253 patients. T2 VBQCSF was significantly different between groups (p < 0.001). The interclass correlation coefficient for inter and intra-rater reliability was 0.767 (95%CI 0.650-0.849) and 0.893 (95%CI 0.834-0.932), respectively. The T2 VBQCSF showed moderate correlations with DEXA BMD (r =  - 0.442, p < 0.001). The area under the ROC curve indicated a predictive accuracy of 76%. A sensitivity of 59.0% with a specificity of 87.5% was achieved for distinguishing low BMD by setting the T2 VBQCSF cutoff at 0.607.

CONCLUSION

Compared to the traditional VBQ score, T2 VBQCSF is a more promising tool for distinguishing poor bone quality in patients with degenerative lumbar disease. A T2 VBQCSF score > 0.607 can identify patients who require additional diagnostic evaluation.

When can we Kick (Some) Humans "Out of the Loop"? An Examination of the use of AI in Medical Imaging for Lumbar Spinal Stenosis

Artificial intelligence (AI) has attracted an increasing amount of attention, both positive and negative. Its potential applications in healthcare are indeed manifold and revolutionary, and within the realm of medical imaging and radiology (which will be the focus of this paper), significant increases in accuracy and speed, as well as significant savings in cost, stand to be gained through the adoption of this technology. Because of its novelty, a norm of keeping humans "in the loop" wherever AI mechanisms are deployed has become synonymous with good ethical practice in some circles. It has been argued that keeping humans "in the loop" is important for reasons of safety, accountability, and the maintenance of institutional trust. However, as the application of machine learning for the detection of lumbar spinal stenosis (LSS) in this paper's case study reveals, there are some scenarios where an insistence on keeping humans in the loop (or in other words, the resistance to automation) seems unwarranted and could possibly lead us to miss out on very real and important opportunities in healthcare-particularly in low-resource settings. It is important to acknowledge these opportunity costs of resisting automation in such contexts, where better options may be unavailable. Using an AI model based on convolutional neural networks developed by a team of researchers at NUH/NUS medical school in Singapore for automated detection and classification of the lumbar spinal canal, lateral recess, and neural foraminal narrowing in an MRI scan of the spine to diagnose LSS, we will aim to demonstrate that where certain criteria hold (e.g., the AI is as accurate or better than human experts, risks are low in the event of an error, the gain in wellbeing is significant, and the task being automated is not essentially or importantly human), it is both morally permissible and even desirable to kick the humans out of the loop.

The effect of lumbar multifidus muscle degeneration on upper lumbar disc herniation

Purpose

This study aimed to investigate the effect of lumbar multifidus muscle (MF) degeneration on upper lumbar disc herniation (ULDH).

Methods

This study used 3.0T magnetic resonance imaging (MRI) T2 axial weighted images to retrospectively analyze 93 ULDH patients and 111 healthy participants. Sixty-five pairs of participants were included in this study using propensity score matching (PSM). Cross-sectional area, fat infiltration area, anteroposterior diameter (APD), lateral diameter (LD), cross-sectional area of the bilateral multifidus muscles at the corresponding level, intervertebral disc area at the corresponding section, and visual analog scale (VAS) score for low back pain (LBP). For inter-group comparisons, we used the t-test, analysis of variance (ANOVA), Mann-Whitney U test, Kruskal-Wallis test, chi-square test, or Fisher's exact test, according to the type of data. We used Pearson correlation analysis to study the correlation between the VAS score and related indicators, and established a predictive model for upper lumbar disc herniation using the receive operative characteristic (ROC) curve analysis method. Finally, univariate and multivariate logistic regression analyses were performed to establish a predictive model for the risk of high lumbar disc herniation.

Results

We compared the fat areas at the lumbar vertebral levels L1/2, L2/3, and L3/4, as well as the left lateral diameter (LD) (MF), L1/2 left lumbar multifidus muscle index (LMFI), and L1/2 total fat infiltration cross-section area (TFCSA), and found significant differences between the case and control groups (P < 0.001). Furthermore, we observed a significant positive correlation (P < 0.05) between the VAS scores and multiple muscle indicators. Additionally, we developed ROC prediction models to assess the risk of lumbar intervertebral disc protrusion at the L1/2, L2/3, and L3/4 levels, with the results identifying L1/2 TFCSA, L2/3 TFCSA, and L3/4 relative psoas major muscle cross-section area (rPMCSA) as the most predictive indicators. Finally, univariate and multivariate logistic regression analyses showed that the L1/2 rPMCSA, L2/3 TFCSA were significantly associated with the risk of lumbar intervertebral disc protrusion in both models.

Conclusion

Degeneration of the MF is significantly correlated with the occurrence of ULDH, and the larger the area of fat infiltration in the MF, the more obvious the lower back pain in ULDH patients. In addition, TFCSA can serve as an indicator of the occurrence of ULDH.

Fatty Infiltration in Paraspinal Muscles: Predicting the Outcome of Lumbar Surgery and Postoperative Complications

Lumbar spine disorders often cause lower back pain, lower limb radiating pain, restricted movement, and neurological dysfunction, which seriously affect the quality of life of middle-aged and older people. It has been found that pathological changes in the spine often cause changes in the morphology and function of the paraspinal muscles (PSMs). Fatty infiltration (FI) in PSMs is closely associated with disc degeneration and Modic changes. And FI causes inflammatory responses that exacerbate the progression of lumbar spine disease and disrupt postoperative recovery. Magnetic resonance imaging can better distinguish between fat and muscle tissue with the threshold technique. Three-dimensional magnetic resonance imaging multi-echo imaging techniques such as water-fat separation and proton density are currently popular for studying FI. Muscle fat content obtained based on these imaging sequences has greater accuracy, visualization, acquisition speed, and utility. The proton density fat fraction calculated from these techniques has been shown to evaluate more subtle changes in PSMs. Magnetic resonance spectroscopy can accurately reflect the relationship between FI and the degeneration of PSMs by measuring intracellular and extracellular lipid values to quantify muscle fat. We have pooled and analyzed published studies and found that patients with spinal disorders often exhibit FI in PSMs. Some studies suggest an association between FI and adverse surgical outcomes, although conflicting results exist. These suggest that clinicians should consider FI when assessing surgical risks and outcomes. Future studies should focus on understanding the biological mechanisms underlying FI and its predictive value in spinal surgery, providing valuable insights for clinical decision-making.

Prognostic factors and novel nomograms for overall survival and cancer specific survival of malignant ovarian cancer patients with bone metastasis: A SEER-based study

OBJECTIVE

Ovarian cancer (OC) is a frequent and fatal disease in women, and bone metastasis of ovarian cancer (OCBM) leads to a poor survival trend. This study aimed to determine the factors which influence overall survival (OS) and cancer-specific survival (CSS) of OCBM patients and to develop prognostic predictive models.

METHODS

Data of OCBM patients were stratified from the Surveillance, Epidemiology and End Results database from 2010 to 2017 and were randomly divided into training and testing datasets (7:3). Prognostic factors were identified by Cox regression analyses and nomograms were then developed. Nomogram models were examined on the discriminative ability and accuracy by calibration plots, Brier score (BS), and time-dependent receiver operating characteristic (ROC) curves. Decision curve analyses (DCA) was used for estimation of the clinical benefit of nomogram models.

RESULTS

Grade, tumor size, tumor metastasis (liver, lung), primary site surgery, chemotherapy, and systemic therapy were realized as independent prognostic factors for OS and CSS, respectively. Agreement between the actual and predicted outcomes was proved by calibration plots. Nomograms performed well in OS and CSS predictions, as shown by area under the ROC curves (AUCs) and BSs for testing dataset as follows: for OS, 3-/6-/12-month AUCs and BSs were 0.778/0.788/0.822 and 19.0/18.5/15.4, respectively; for CSS, 3-/6-/12-month AUCs and BSs were 0.799/0.806/0.832 and 18.1/18.0/15.4, respectively. DCA suggested an agreeable clinical benefit of both nomograms.

CONCLUSION

The nomograms developed for OCBM patients' survival prediction were proved to be accurate, efficient, and clinically beneficial, which were further deployed as web-based calculators to help in clinical decision making and future studies.

A Retrospective Study of the Effect of Spinopelvic Parameters on Fatty Infiltration in Paraspinal Muscles in Patients With Lumbar Spondylolisthesis

OBJECTIVE

The effect on fat infiltration (FI) of paraspinal muscles in degenerative lumbar spinal diseases has been demonstrated except for spinopelvic parameters. The present study is to identify the effect of spinopelvic parameters on FI of paraspinal muscle (PSM) and psoas major muscle (PMM) in patients with degenerative lumbar spondylolisthesis.

METHODS

A single-center, retrospective cross-sectional study of 160 patients with degenerative lumbar spondylolisthesis (DLS) and lumbar stenosis (LSS) who had lateral full-spine x-ray and lumbar spine magnetic resonance imaging was conducted. PSM and PMM FIs were defined as the ratio of fat to its muscle cross-sectional area. The FIs were compared among patients with different pelvic tilt (PT) and pelvic incidence (PI), respectively.

RESULTS

The PSM FI correlated significantly with pelvic parameters in DLS patients, but not in LSS patients. The PSM FI in pelvic retroversion (PT > 25°) was 0.54 ± 0.13, which was significantly higher in DLS patients than in normal pelvis (0.41 ± 0.14) and pelvic anteversion (PT < 5°) (0.34 ± 0.12). The PSM FI of DLS patients with large PI ( > 60°) was 0.50 ± 0.13, which was higher than those with small ( < 45°) and normal PI (0.37 ± 0.11 and 0.36 ± 0.13). However, the PSM FI of LSS patients didn't change significantly with PT or PI. Moreover, the PMM FI was about 0.10-0.15, which was significantly lower than the PSM FI, and changed with PT and PI in a similar way of PSM FI with much less in magnitude.

CONCLUSION

FI of the PSMs increased with greater pelvic retroversion or larger pelvic incidence in DLS patients, but not in LSS patients.

Cross-sectional area and fat infiltration of the lumbar spine muscles in patients with back disorders: a deep learning-based big data analysis

PURPOSE

Validated deep learning models represent a valuable option to perform large-scale research studies aiming to evaluate muscle quality and quantity of paravertebral lumbar muscles at the population level. This study aimed to assess lumbar spine muscle cross-sectional area (CSA) and fat infiltration (FI) in a large cohort of subjects with back disorders through a validated deep learning model.

METHODS

T2 axial MRI images of 4434 patients (n = 2609 females, n = 1825 males; mean age: 56.7 ± 16.8) with back disorders, such as fracture, spine surgery or herniation, were retrospectively collected from a clinical database and automatically segmented. CSA, expressed as the ratio between total muscle area (TMA) and the vertebral body area (VBA), and FI, in percentages, of psoas major, quadratus lumborum, erector spinae, and multifidus were analyzed as primary outcomes.

RESULTS

Male subjects had significantly higher CSA (6.8 ± 1.7 vs. 5.9 ± 1.5 TMA/VBA; p < 0.001) and lower FI (21.9 ± 8.3% vs. 15.0 ± 7.3%; p < 0.001) than females. Multifidus had more FI (27.2 ± 10.6%; p < 0.001) than erector spinae (22.2 ± 9.7%), quadratus lumborum (17.5 ± 7.0%) and psoas (13.7 ± 5.8%) whereas CSA was higher in erector spinae than other lumbar muscles. A high positive correlation between age and total FI was detected (rs = 0.73; p < 0.001) whereas a negligible negative correlation between total CSA and age was observed (rs =  - 0.24; p < 0.001). Subjects with fractures had lower CSA and higher FI compared to those with herniations, surgery and with no clear pathological conditions.

CONCLUSION

CSA and FI values of paravertebral muscles vary a lot in accordance with subjects' sex, age and clinical conditions. Given also the large inter-muscle differences in CSA and FI, the choice of muscles needs to be considered with attention by spine surgeons or physiotherapists when investigating changes in lumbar muscle morphology in clinical practice.

The Difference in Paraspinal Muscle Parameters and the Correlation with Health-Related Quality of Life among Healthy Individuals, Patients with Degenerative Lumbar Scoliosis and Lumbar Spinal Stenosis

(1) Background: Paraspinal muscle degeneration affects the quality of life in patients with degenerative lumbar scoliosis (DLS) and lumbar spinal stenosis (LSS). We aimed to describe the characteristics and differences in the paraspinal muscle parameters between patients with DLS and LSS and investigate their correlation with health-related quality of life (HRQOL). (2) Methods: There were forty-four participants in each group, namely the DLS, LSS, and healthy groups, who were matched at a ratio of 1:1 according to age, sex, and BMI. Differences in paraspinal muscle parameters among the three groups were compared using analysis of variance or the Mann-Whitney U test, and paraspinal muscle degeneration and HRQOL were analyzed using Spearman's correlation analysis. (3) Results: In the upper lumbar, the psoas (PS), quadratus lumborum (QL), and multifidus (MF) cross-sectional area (CSA) in the DLS group were smaller than those in the other groups. In the lower lumbar region, the CSA of the PS, QL, erector spinae (ES), and gross CSA (GCSA) of the MF in the DLS group were not significantly different from those in the LSS group. These values were lower than those observed in the healthy group. The lean muscle fat index (LMFI) of the MF and ES groups was higher than those of the other groups. Regarding HRQOL, we found that PS and MF CSA were strongly associated with HRQOL in healthy individuals; however, only MF was associated with HRQOL in the LSS group. (4): Conclusion: PS in the upper lumbar region and MF degeneration were more severe in patients with DLS than in those with LSS. ES degeneration was similar between the LSS and DLS groups. MF muscle atrophy in patients with LSS and asymmetric changes in the MF in DLS are associated with quality of life.

Dependence of trunk muscle size and position on age, height, and weight in a multi-ethnic cohort of middle-aged and older men and women

Trunk muscle size and location relative to the spine are key factors affecting their capacity to assist in trunk movement, strength, and function. There remains limited information on how age, weight and height affect these measurements across multiple spinal levels, and prior studies had limited samples in terms of size and ethnicity. In this study, we measured trunk muscles in coronal plane slices at T4 - L4 of CT scans acquired in 507 participants, aged 40-90 years, from the community-based Framingham Heart Study. Mixed-effects linear regressions, stratified by sex, determined the contributions of age, height and weight, to muscle cross-sectional area (CSA), the distance from the vertebral body centroid (CD), and the in-plane angle of the line between the vertebral body and the muscle centroids (CA). Muscle CSA decreased with higher age by an average of -0.8% per year, but weight (average 0.8% per kg) and height (average -0.05% per cm) had mixed results, with both positive and negative effects depending on muscle group and level. Muscle CD increased with weight by an average of 0.3% per kg, but had mixed effects for age (average 0.8% per year) and height (average 0.1% per cm). Muscle CA had mixed associations with age (average 0.05% per year), weight (average 0.01% per kg) and height (average -0.05% per cm). A prediction program created with these results provides a simple approach for estimating probable values for trunk muscle size and position in the absence of medical imaging.

The association between lumbar paraspinal muscle functional cross-sectional area on MRI and regional volumetric bone mineral density measured by quantitative computed tomography

Osteosarcopenia is a common condition among elderly and postmenopausal female patients. Site-specific bone mineral density is more predictive of bone-related complications. Few studies have investigated muscle-bone associations. Our results demonstrated that in women, significant positive associations between paraspinal muscles FCSA and vBMD exist at different lumbosacral levels. These regional differences should be considered when interpreting bone-muscle associations in the lumbar spine.

INTRODUCTION

There is increasing evidence between bone and muscle volume associations. Previous studies have demonstrated comorbidity between osteoporosis and sarcopenia. Recent studies showed that sarcopenic subjects had a fourfold higher risk of concomitant osteoporosis compared to non-sarcopenic individuals. Although site-specific bone mineral density (BMD) assessments were reported to be more predictive of bone-related complications after spinal fusions than BMD assessments in general, there are few studies that have investigated level-specific bone-muscle interactions. The aim of this study is to investigate the associations between muscle functional cross-sectional area (FCSA) on magnetic resonance imaging (MRI) and site-specific quantitative computed tomography (QCT) volumetric bone mineral density (vBMD) in the lumbosacral region among spine surgery patients.

METHODS

We retrospectively reviewed a prospective institutional database of posterior lumbar fusion patients. Patients with available MRI undergoing posterior lumbar fusion were included. Muscle measurements and FCSA were conducted and calculated utilizing a manual segmentation and custom-written program at the superior endplate of the L3-L5 vertebrae level. vBMD measurements were performed and calculated utilizing a QCT pro software at L1-L2 levels and bilateral sacral ala. We stratified by sex for all analyses.

RESULTS

A total of 105 patients (mean age 61.5 years and 52.4% females) were included. We found that female patients had statistically significant lower muscle FCSA than male patients. After adjusting for age and body mass index (BMI), there were statistically significant positive associations between L1-L2 and S1 vBMD with L3 psoas FCSA as well as sacral ala vBMD with L3 posterior paraspinal and L5 psoas FCSA. These associations were not found in males.

CONCLUSIONS

Our results demonstrated that in women, significant positive associations between the psoas and posterior paraspinal muscle FCSA and vBMD exist in different lumbosacral levels, which are independent of age and BMI. These regional differences should be considered when interpreting bone and muscle associations in the lumbar spine.

Is preoperative fat infiltration in lumbar spine muscles associated with worse clinical outcomes after lumbar interbody fusion?

PURPOSE

Lumbar musculature has a fundamental role in spine stability and spinal balance. Muscle atrophy and fat infiltration play an important role in pain pathophysiology. Accordingly, the preoperative condition of lumbar muscles may influence clinical outcomes after surgical treatment. In this context, the aim of this study was to evaluate the association between preoperative lumbar paravertebral muscle fat infiltration and clinical outcomes after lumbar interbody fusion.

METHODS

A retrospective study of patients with lumbar pathology submitted to lumbar transforaminal (TLIF) or posterior interbody fusion (PLIF) was performed, with a minimum of two years of follow-up. Preoperative lumbar magnetic resonance imaging (MRI) images were classified for fat infiltration in lumbar multifidus muscle and correlated with clinical outcomes.

RESULTS

Seventy-five patients were included: 24 submitted to PLIF and 51 to TLIF. Most patients underwent surgery for spondylolisthesis (67%). Higher degrees of fat infiltration were associated with more advanced age (54.8 vs. 49.1 years old, p = 0.04) and more leg pain after surgery (p = 0.04). No statistically significant differences in other clinical outcomes such as Oswestry Disability Index, visual analogue scale for back and leg pain, self-reported back pain relief, return to work and overall satisfaction were found between different groups of fat infiltration. The improvement in leg pain was associated with improvement in self-reported lumbar pain (p < 0.001).

CONCLUSION

Age and preoperative degree of fat infiltration may be important to predict improvement in leg pain after lumbar interbody fusion. The absence of solid literature on this topic and universal assessment methodologies reinforce the need for further studies.

Is preoperative fat infiltration in lumbar spine muscles associated with worse clinical outcomes after lumbar interbody fusion?

PURPOSE

Lumbar musculature has a fundamental role in spine stability and spinal balance. Muscle atrophy and fat infiltration play an important role in pain pathophysiology. Accordingly, the preoperative condition of lumbar muscles may influence clinical outcomes after surgical treatment. In this context, the aim of this study was to evaluate the association between preoperative lumbar paravertebral muscle fat infiltration and clinical outcomes after lumbar interbody fusion.

METHODS

A retrospective study of patients with lumbar pathology submitted to lumbar transforaminal (TLIF) or posterior interbody fusion (PLIF) was performed, with a minimum of two years of follow-up. Preoperative lumbar magnetic resonance imaging (MRI) images were classified for fat infiltration in lumbar multifidus muscle and correlated with clinical outcomes.

RESULTS

Seventy-five patients were included: 24 submitted to PLIF and 51 to TLIF. Most patients underwent surgery for spondylolisthesis (67%). Higher degrees of fat infiltration were associated with more advanced age (54.8 vs. 49.1 years old, p = 0.04) and more leg pain after surgery (p = 0.04). No statistically significant differences in other clinical outcomes such as Oswestry Disability Index, visual analogue scale for back and leg pain, self-reported back pain relief, return to work and overall satisfaction were found between different groups of fat infiltration. The improvement in leg pain was associated with improvement in self-reported lumbar pain (p < 0.001).

CONCLUSION

Age and preoperative degree of fat infiltration may be important to predict improvement in leg pain after lumbar interbody fusion. The absence of solid literature on this topic and universal assessment methodologies reinforce the need for further studies.

The difference of paraspinal muscle between patients with lumbar spinal stenosis and normal middle-aged and elderly people, studying by propensity score matching

OBJECTIVE

The purpose of this study was to elaborate the characteristics of paraspinal muscles in lower lumbar, to compare the differences of paraspinal muscle between patients with lumbar spinal stenosis and normal people and to explore the influencing factors of paraspinal muscle degeneration in patients with lumbar spinal stenosis.

METHOD

The 39 pairs of patients and normal people were selected by propensity score matching. The differences of multifidus muscle and erection spine muscle parameters between the two groups were compared by independent-samples t-test and the relationship between age, paraspinal muscle degeneration and other factors in patients with lumbar spinal stenosis was analyzed by Pearson or Spearman correlation analysis.

RESULT

The general conditions of the two groups (patients with lumbar spinal stenosis and normal people) were well matched. There were significant differences in the relative fatty cross sectional area, fatty infiltration and relative signal intensity of multifidus muscle at L3 level. The fatty infiltration and relative signal intensity of multifidus muscle at L4 level and the relative signal intensity of multifidus muscle at L5 level were also significantly different. For male, the relative fatty cross sectional area, the fatty infiltration and relative signal intensity of multifidus muscle in patients were higher than those in healthy peers. For female, the relative signal intensity of multifidus muscle in patients was higher, too. In patients group, age was significantly correlated with the relative fatty cross sectional area, fatty infiltration and relative signal intensity of multifidus muscle and erector spinae muscle. Weight and BMI were significantly correlated with the relative total cross-sectional area of erector spinae muscle. The fatty infiltration increased more significantly with age in patients than that in normal people.

CONCLUSION

The change rules of paraspinal muscles in patients with lumbar spinal stenosis are similar to those in normal people. The degeneration of paraspinal muscle in patients with lumbar spinal stenosis was more severe than that in normal people, mostly in multifidus muscle. The paraspinal muscle degeneration was related to age in patients, and the effect of age on atrophy of paraspinal muscle was greater than that of normal people.

Standard values for temporal muscle thickness in the Japanese population who undergo brain check-up by magnetic resonance imaging

BACKGROUND

Skeletal muscle mass is an important factor for various diseases' outcomes. The psoas muscle cross-sectional area on the abdominal computed tomography (CT), gait speed, and handgrip strength is used to measure it. However, it is difficult to measure the neurological patients' muscle mass or function because (1) we do not perform abdominal CT. (2) Such patients have impaired consciousness, gait disturbance, paresis, and need of rest. Temporal muscle thickness (TMT) on magnetic resonance imaging (MRI) is now attractive for skeletal muscle volume indicator, but the reference values are not established. We herein investigated the standard value of the Japanese TMT using the brain check-up database by MRI.

METHODS

We retrospectively investigated 360 Japanese individuals from two institutions between 2017 and 2019. We measured TMT on the T1-weighted images in the previously reported way. The associations between TMT and other variables were analyzed.

RESULTS

TMT of 214 women and 146 men, ranging from 35 to 84 years old, was investigated. TMT ranged from 3.69 to 16.90 mm. Mean TMT values were significantly higher in men compared to women except for the over 70-year-old cohort. TMT was correlated to weight and body mass index in both sexes.

CONCLUSION

This is the first retrospective study on the standard TMT values from the Japanese brain check-up database. Our results were just reference values, but these would be useful for further investigation in other neurosurgical and neurological diseases regarding muscle volume or sarcopenia.