Deep learning-based structure segmentation and intramuscular fat annotation on lumbar magnetic resonance imaging.

Background: Lumbar disc herniation (LDH) is a prevalent cause of low back pain. LDH patients commonly experience paraspinal muscle atrophy and fatty infiltration (FI), which further exacerbates the symptoms of low back pain. Magnetic resonance imaging (MRI) is crucial for assessing paraspinal muscle condition. Our study aims to develop a dual-model for automated muscle segmentation and FI annotation on MRI, assisting clinicians evaluate LDH conditions comprehensively. Methods: The study retrospectively collected data diagnosed with LDH from December 2020 to May 2022. The dataset was split into a 7:3 ratio for training and testing, with an external test set prepared to validate model generalizability. The model's performance was evaluated using average precision (AP), recall and F1 score. The consistency was assessed using the Dice similarity coefficient (DSC) and Cohen's Kappa. The mean absolute percentage error (MAPE) was calculated to assess the error of the model measurements of relative cross-sectional area (rCSA) and FI. Calculate the MAPE of FI measured by threshold algorithms to compare with the model. Results: A total of 417 patients being evaluated, comprising 216 males and 201 females, with a mean age of 49 ± 15 years. In the internal test set, the muscle segmentation model achieved an overall DSC of 0.92 ± 0.10, recall of 92.60%, and AP of 0.98. The fat annotation model attained a recall of 91.30%, F1 Score of 0.82, and Cohen's Kappa of 0.76. However, there was a decrease on the external test set. For rCSA measurements, except for longissimus (10.89%), the MAPE of other muscles was less than 10%. When comparing the errors of FI for each paraspinal muscle, the MAPE of the model was lower than that of the threshold algorithm. Conclusion: The models demonstrate outstanding performance, with lower error in FI measurement compared to thresholding algorithms.

New complex cell junctions in and around the intervertebral discs discovered using autoantibodies from patients affected by endemic pemphigus foliaceus in El Bagre, Colombia, South America.

BACKGROUND: Traditionally, the intervertebral disks' (IVD) nucleus pulposus (NP) and annulus fibrosus (AF) are considered to have few cellular components and cell junctions. Patients affected by a new variant of endemic pemphigus foliaceus in El Bagre, Colombia, experience back pain in the spinal areas of the lower and upper back. Here, we investigate the reactivity of the patient's autoantibodies to structures in and around the IVDs at the cellular level. METHODS: We first administered a questionnaire and performed a medical examination. We then tested for autoreactivity against IVDs by indirect immunofluorescence, confocal microscopy, and reflectance confocal microscopy using bovine and human tissues as antigen sources. We tested 45 sera from patients affected by the disease and 45 control sera from the endemic area matched by age, gender, demographics, and work activity. RESULTS: Most of the patient sera revealed polyclonal antibodies against newly discovered cell junctions in the NP and AF, including their translamellar cross-bridges. Additional reactivities were detected against cell junctions in the spinal cord neurons, paraspinal nerves, blood vessels, anterior and posterior longitudinal ligaments, and paraspinal skeletal muscles. The reactivities of the patient's autoantibodies co-localized with those of commercially available antibodies to desmoplakins I-II, armadillo repeat gene deleted in velo-cardio-facial syndrome, plakophilin-4, and myocardium-enriched zonula occludens-1-associated protein (p < 0.001). CONCLUSIONS: We discovered novel complex cell junctions in the IVDs using patients' autoantibodies. These discoveries open a new chapter in the knowledge of IVD, representing a breakthrough pertinent to many diseases.

Integrating Ultrasound-Guided Multifidus Injections with Repeated Peripheral Magnetic Stimulation for Low Back Pain: A Feasibility Study.

Background: Low back pain is a globally prevalent musculoskeletal issue. Repetitive peripheral magnetic stimulation (rPMS) is emerging as a promising modality for managing musculoskeletal pain, while ultrasound-guided lumbar facet/multifidus injections are a potential therapeutic option for low back pain. This study explores the feasibility of combining these two treatments for managing low back pain. Materials and Methods: Ultrasound-guided injections were administered using 5 mL of 50% dextrose and 5 mL of 1% lidocaine. Bilateral injections targeted the L4/L5 and L5/S1 facet joints with 1 mL at each site, and the remaining 8 mL was distributed over the multifidus muscles using peppering techniques. Following injections, rPMS therapy was conducted with the TESLA Stym® device, targeting the bilateral lumbosacral region over 12 sessions. Pain intensity was measured using the visual analog scale (VAS), and disability was assessed with the Oswestry disability index (ODI) at baseline, after six sessions, and after 12 sessions of rPMS. Results: Three participants were enrolled. Baseline VAS and ODI scores were 8.33 ± 0.29 cm and 49.63 ± 1.28%, respectively. After six rPMS sessions, VAS and ODI scores changed to 4.33 ± 3.75 cm and 21.48 ± 19.42%, respectively. After 12 sessions, VAS decreased to 0.83 ± 1.44 cm and ODI to 5.19 ± 8.98%. Significant differences were observed between baseline and final assessments. Conclusion: Combining ultrasound-guided lumbar facet/multifidus injections with rPMS shows promise for treating low back pain. However, long-term efficacy and comparison with conventional treatments require further investigation through prospective randomized controlled trials.

Effect of Paravertebral Muscle Degeneration on Lumbar and Pelvic Sagittal Alignment in Patients With Degenerative Scoliosis.

STUDY DESIGN: Retrospective study. OBJECTIVES: To explore the relationship between lumbar spine muscle mass and lumbar pelvic sagittal parameters in patients with degenerative scoliosis. METHODS: This study included ADS patients who were treated in our hospital from 2019 to 2023. The spinal parameters were evaluated through X-rays, and the relative muscle volume (RMV) and fat infiltration (FI) were measured through three-dimensional reconstruction. Patients were categorized into 3 groups based on SRS-Schwab sagittal balance correction (0, +, ++), and into 3 groups based on GAP score (proportioned, moderately dis-proportioned, severely dis-proportioned). Finally, patients were classified into low-quality and high-quality groups based on the FI of Paraspinal muscles (PSM). RESULTS: The study included a total of 63 patients. Significant statistical differences were observed in the FI and RMV of MF, ES and PS among patients classified by SRS-Schwab PT classification. Additionally, significant statistical differences were found in the RMV of MF and PS among patients classified by SRS-Schwab PI-LL classification and GAP score. Furthermore, a significant correlation was found between the FI and RMV of PSM and lumbopelvic sagittal parameters. The ordinal regression model analysis revealed that FI of ES significantly impacted PT imbalance, while RMV of MF significantly impacted PI-LL imbalance. Moreover, significant differences were noted in PT and PI between the low-quality and high-quality multifidus groups. CONCLUSIONS: As sagittal imbalance worsens, PSM degeneration also intensifies, primarily characterized by an increase in FI and a decrease in RMV. Notably, PT and PI-LL are positively correlated with RMV and negatively correlated with FI.

Musculoskeletal Dimension and Brightness Reference Values in Lumbar Magnetic Resonance Imaging-A Radio-Anatomic Investigation in 80 Healthy Adult Individuals.

Background/Objectives: Magnetic resonance imaging (MRI) is the preferred diagnostic means to visualize spinal pathologies, and offers the possibility of precise structural tissue analysis. However, knowledge about MRI-based measurements of physiological cross-sectional musculoskeletal dimensions and associated tissue-specific average structural brightness in the lumbar spine of healthy young women and men is scarce. The current study was planned to investigate characteristic intersexual differences and to provide MRI-related musculoskeletal baseline values before the onset of biological aging. Methods: At a single medical center, lumbar MRI scans of 40 women and 40 men aged 20-40 years who presented with moderate nonspecific low back pain were retrospectively evaluated for sex-specific differences in cross-sectional sizes of the fifth lumbar vertebrae, psoas and posterior paravertebral muscles, and respective sex- and age-dependent average brightness alterations on T2-weighted axial sections in the L5-level. Results: In women (mean age 33.5 years ± 5.0 (standard deviation)), the investigated musculoskeletal cross-sectional area sizes were significantly smaller (p < 0.001) compared to those in men (mean age 33.0 years ± 5.7). Respective average musculoskeletal brightness values were higher in women compared to those in men, and most pronounced in posterior paravertebral muscles (p < 0.001). By correlating brightness results to those of subcutaneous fat tissue, all intersexual differences, including those between fifth lumbar vertebrae and psoas muscles, turned out to be statistically significant. This phenomenon was least pronounced in psoas muscles. Conclusions: Lumbar musculoskeletal parameters showed significantly larger dimensions of investigated anatomical structures in men compared to those in women aged 20-40 years, and an earlier onset and faster progress of bone loss and muscle degradation in women.

Lumbar Extensor Muscle Strength and Physical Performance in Community-Dwelling Older Adults: Findings From SarcoSpine Cohort.

BACKGROUND: The lumbar extensor muscles (LEMs) play an important role in body posture and physical function in older adults. Because lumbar extensor strength decreases more rapidly than limb muscle strength with age, it should be evaluated to aid healthy aging. This study investigated the association between LEM strength and physical performance in community-dwelling older adults. METHODS: This prospective observational cohort study of spinal sarcopenia (SarcoSpine) was conducted at a single center. One hundred and ten consecutive individuals who completed the baseline survey, including conventional sarcopenic indices, lumbar spine three-dimensional magnetic resonance imaging, isokinetic lumbar extensor strength, and physical performance tests (Short Physical Performance Battery, Berg Balance Scale, and Back Performance Scale [BPS]), were enrolled. A multivariate linear regression analysis was performed to determine the variables for evaluating their association with LEM strength. RESULTS: Among the conventional sarcopenic indices, gait speed was significantly correlated with Short Physical Performance Battery results and Berg Balance Scale score in men and women. Handgrip strength was significantly correlated with the BPS score for both sexes. In the multivariable linear regression, age (ß = -2.12, p < .01) and BPS score (ß = -3.54, p = .01, R2 = .29) were independent indicators of LEM strength. CONCLUSIONS: Our findings reveal the substantial association between LEM strength and BPS score in older women. The targeted intervention aimed at improving the LEMs strength would be needed to enhance physical performance in the aging population.

Cervical facet joint degeneration, facet joint angle and paraspinal muscle degeneration are correlated with degenerative cervical spondylolisthesis at C4/5: a propensity score-matched study.

BACKGROUND CONTEXT: Prior studies have hypothesized that degenerative cervical spondylolisthesis (DCS) may be influenced by loss of stability due to disc, facet joint or cervical alignment. Meanwhile, it is commonly believed that the facet joints and paraspinal muscles participate in maintaining cervical spine stability. However, the impact of paraspinal muscle morphology and detailed facet joint features on DCS requires further investigation. PURPOSE: To compare facet joint characteristics, disc degeneration and muscle morphology between patients with DCS and those without DCS. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: Consecutive surgical patients with degenerative cervical spondylosis from June 2016 to August 2023 were recruited. OUTCOME MEASURES: DCS was assessed on X-ray based on the translation distance. Cervical facet joint degeneration (CFD), the facet joint angle on the axial plane (FA-A) and the facet joint angle on the sagittal plane (FA-S), and facet joint tropism (FT) were measured on computerized tomography (CT). Paraspinal muscle degeneration was assessed on magnetic resonance imaging (MRI) including by the adjusted cross-sectional area (aCSA), the functional aCSA, the fat infiltration ratio (FI%). The Pfirrmann grade of the cervical disc was also evaluated. METHODS: Demographic and clinical data were compared in matched and unmatched cohorts. Disc degeneration, muscle degeneration and facet joint characteristics, including FA, FT and CFD, were compared between patients with and without DCS. Furthermore, the degree of CFD was compared with that of adjacent segments in both groups. Additionally, logistic regression was performed to determine independent risk factors for DCS. Finally, the receiver operating characteristic (ROC) curve, area under the curve (AUC) and cutoff value for the risk factors were calculated. RESULTS: A total of 431 surgical patients were propensity score matched for age, sex and BMI, and 146 patients were included in the final analysis, with 73 patients in the DCS group and 73 patients in the non-DCS group. DCS patients exhibited more severe CFD at C4/5 (segment with spondylolisthesis). Additionally, DCS was generally associated with more severe CFD, a more horizontal FA-S, more FT and worse paraspinal muscle health but similar disc degeneration. In addition, anterior spondylolisthesis was related to more severe CFD and decreased functional aCSA of the flexors and extensors. Finally, more severe CFD, a more horizontal FA-S and a higher FI% on deep extensor were revealed to be risk factors for DCS, with cutoff values of 1.5, 44.5̊, and 37.1%, respectively. CONCLUSIONS: This study demonstrated that CFD, the FA and FT and parasipnal muscle degeneration were associated with DCS. And may provide novel insight into the pathogenesis and nature history of DCS and suggest the evolution of degeneration in the cervical spine.

Assessment of lumbar paraspinal muscle morphology using mDixon Quant magnetic resonance imaging (MRI): a cross-sectional study in healthy subjects.

Background: Lumbar paraspinal muscles (LPM) are a part of the deep spinal stabilisation system and play an important role in stabilising the lumbar spine and trunk. Inadequate function of these muscles is thought to be an essential aetiological factor in low back pain, and several neuromuscular diseases are characterised by dysfunction of LPM. The main aims of our study were to develop a methodology for LPM assessment using advanced magnetic resonance imaging (MRI) methods, including a manual segmentation process, to confirm the measurement reliability, to evaluate the LPM morphological parameters [fat fraction (FF), total muscle volume (TMV) and functional muscle volume (FMV)] in a healthy population, to study the influence of physiological factors on muscle morphology, and to build equations to predict LPM morphological parameters in a healthy population. Methods: This prospective cross-sectional observational comparative single-centre study was conducted at the University Hospital in Brno, enrolling healthy volunteers from April 2021 to March 2023. MRI of the lumbar spine and LPM (erector spinae muscle and multifidus muscle) were performed using a 6-point Dixon gradient echo sequence. The segmentation of the LPM and the control muscle (psoas muscle) was done manually to obtain FF and TMV in a range from Th12/L1 to L5/S1. Intra-rater and inter-rater reliability were evaluated. Linear regression models were constructed to assess the effect of physiological factors on muscle FF, TMV and FMV. Results: We enrolled 90 healthy volunteers (median age 38 years, 45 men). The creation of segmentation masks and the assessment of FF and TMV proved reliable (Dice coefficient 84% to 99%, intraclass correlation coefficient ≥0.97). The univariable models showed that FF of LPM was influenced the most by age (39.6% to 44.8% of variability, P<0.001); TMV and FMV by subject weight (34.9% to 67.6% of variability, P<0.001) and sex (24.7% to 64.1% of variability, P<0.001). Multivariable linear regression models for FF of LPM included age, body mass index and sex, with R-squared values ranging from 45.4% to 51.1%. Models for volumes of LPM included weight, age and sex, with R-squared values ranged from 37.4% to 76.8%. Equations were developed to calculate predicted FF, TMV and FMV for each muscle. Conclusions: A reliable methodology has been developed to assess the morphological parameters (biomarkers) of the LPM. The morphological parameters of the LPM are significantly influenced by physiological factors. Equations were constructed to calculate the predicted FF, TMV and FMV of individual muscles in relation to anthropometric parameters, age, and sex. This study, which presented LPM assessment methodology and predicted values of LPM morphological parameters in a healthy population, could improve our understanding of diseases involving LPM (low back pain and some neuromuscular diseases).

Hounsfield units of vertebrae as a predictor of cervical deep paraspinal muscles atrophy and neck pain in degenerative cervical myelopathy.

OBJECTIVE: This study investigated the correlation between Hounsfield units (HU) of the cervical vertebrae and atrophy of the cervical deep paraspinal muscles, namely the multifidus and semispinalis cervicis (SCer), in patients diagnosed with degenerative cervical myelopathy (DCM). METHODS: The authors retrospectively analyzed data from 136 patients aged 50-79 years (81 males and 55 females) who underwent surgical intervention for DCM. HU measurements of the cancellous bone in the C4 vertebra were acquired through standardized techniques. The authors evaluated fatty infiltration (FI); analyzed functional and vertebral cross-sectional area (CSA) of the multifidus and SCer at the C4-5, C5-6, and C6-7 levels; and analyzed the presence of Modic changes (MCs) and the incidence of axial neck pain. RESULTS: Patients were categorized into group A (n = 56) with mean ± SD HU of 293.3 ± 15.6 and group B (n = 80) with mean ± SD HU of 389.5 ± 10.6. Both groups demonstrated significant improvements in postoperative clinical outcomes (p < 0.05); however, no statistically significant difference was observed (p > 0.05). Significant disparities in HU measurements and visual analog scale (VAS) scores for neck pain were observed between the groups (p < 0.05). The highest VAS score correlated with MCs-1 type (i.e., low signal on T1-weighted images and high signal on T2-weighted images). The functional CSA to vertebral CSA ratios of the multifidus and SCer in group A were markedly reduced compared to those of group B (p < 0.05). No significant difference was noted in functional CSA asymmetry between the groups for both muscles (p > 0.05). Lower HU measurements directly correlated with increased FI in the multifidus (p = 0.002) and SCer (p = 0.035). Furthermore, a strong positive association was found between the functional CSA to vertebral CSA ratio of the multifidus and HU values (p = 0.003), whereas HU measurements and VAS scores exhibited a negative correlation (p = 0.020). CONCLUSIONS: Among those patients older than 50 years with DCM, those with decreased HU values demonstrated elevated FI levels in the multifidus and SCer muscles. Moreover, these patients presented with pronounced muscle atrophy, which correlated with axial neck pain. A significant relationship was also identified between MCs and diminished HU values.

The Association between prior arthroplasty and Paraspinal Muscle Degeneration in patients undergoing elective lumbar surgery.

PURPOSE: Spinal and lower extremity degeneration often causes pain and disability. Lower extremity osteoarthritis, eventually leading to total knee- (TKA) and -hip arthroplasty (THA), can alter posture through compensatory mechanisms, potentially causing spinal misalignment and paraspinal muscle (PM) atrophy. This study aims to evaluate the association between prior THA or TKA and PM-degeneration in patients undergoing elective lumbar surgery for degenerative conditions. METHODS: A retrospective analysis of patients undergoing lumbar surgery for degenerative conditions was conducted. Patients were categorized based on prior THA, TKA, or both. Quantitative analysis of functional cross-sectional area (fCSA) and fat infiltration (FI) of psoas, multifidus (MF), and erector spinae (ES) muscles at L4-level was performed using T2-weighted MRI images. The association between the FI and fCSA of the PM and prior arthroplasty was investigated. Differences were assessed using ANOVA and multivariable linear regression. RESULTS: Overall, 584 patients (60% female, 64 ± 12 years) were included. 66 patients (11%) had prior TKA, 36 patients (6%) THA, and 15 patients (3%) both TKA and THA. Patients with arthroplasty were mostly female (57%) and notably older (p < 0.001). The FI of the MF and the ES was significantly higher in the arthroplasty-group (both p < 0.001). Patients with prior TKA showed significantly higher FI (Est = 4.3%, p = 0.013) and lower fCSA (Est=-0.9 cm2, p = 0.012) in the MF compared to the non-arthroplasty-group. CONCLUSION: This study demonstrates a significant lower fCSA and higher FI in the MF among individuals with prior TKA. This highlights the complex knee-spine relationship and how these structures interact with each other.

Risk factors of domino osteoporotic vertebral fractures is severe paraspinal muscle fatty degeneration.

BACKGROUND CONTEXT: Domino osteoporotic vertebral fractures (OVFs) involve multiple OVFs occurring simultaneously or sequentially, before healing of the initial OVFs. However, the risk factors and long-term clinical outcomes of domino OVFs are unclear. PURPOSE: To identify the risk factors associated with domino OVFs and to assess their impact on patients' quality of life (QOL). STUDY DESIGN/SETTING: Multicenter prospective observational cohort study. PATIENT SAMPLE: Patients (n = 190) treated conservatively for acute OVFs in 8 hospitals with 12-month follow-up. OUTCOME MEASURES: Clinical outcomes were assessed using the visual analog scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ). Multivariate analyses were performed to identify risk factors for domino OVFs. METHODS: All patients underwent magnetic resonance imaging (MRI) at 3 months to detect subsequent domino OVFs. Domino OVF group included initial domino OVFs (multiple acute OVFs at baseline) and subsequent domino OVFs at 3 months. Paraspinal muscle assessment was performed using the lumbar indentation value and Goutallier classification. Patient characteristics, bone quality, paravertebral muscle degeneration, nutritional status, radiographic parameters, and QOL scores were compared between the nondomino and domino OVF groups. RESULTS: We evaluated 50 (26.3%) patients with domino OVFs (34 with initial domino OVFs; 20 with subsequent domino OVFs). Walking ability was poorer in the domino than in the nondomino OVF group, from baseline to the 12 months follow-up. Groups with 3 or more adjacent domino OVFs showed worse VAS and ODI scores. Multivariate logistic regression analysis revealed that severe fatty degeneration of the paraspinal muscle was an independent risk factor for domino OVFs. CONCLUSIONS: Severe paraspinal muscle fatty degeneration is an independent risk factor for domino OVFs. Our study showed that the quality, rather than the quantity, of paraspinal muscles had an impact on domino OVFs. Early assessment of fatty degeneration in the paraspinal muscles is essential for predicting the development of domino OVFs.

Differentiation of Post-Polio Syndrome from Prior Poliomyelitis Sequela by Assessing Paraspinal Muscle Involvement in Magnetic Resonance Imaging.

Background/Objectives: Post-polio syndrome (PPS) affects former polio patients, manifesting decades after initial infection with progressive symptoms like pain, fatigue, and muscle weakness. Diagnosis relies on the clinical criteria and exclusion of other probable causes. The purpose of this study is to determine the scope and new diagnostic value of magnetic resonance imaging (MRI) in identifying muscle involvement in PPS and distinguishing it from prior poliomyelitis (PPM). Methods: This study was approved by the Koç University Ethics Committee with Approval No. 2023.409.IRB2.090. Electronic medical archives from two academic institutions were searched for records tagged with ICD code B-91 for poliomyelitis sequalae. The resulting search query of 291 records was manually sorted for PPS and PPM, medical history, clinical examination findings, and lumbar MR images down to 32 patients. Two independent radiologists evaluated the paraspinal musculature in the MRIs using the Mercuri scale. Inter-rater agreement, comparison of the paraspinal musculatures between groups, and their relationship to leg involvement were assessed with the resulting data. Results: Inter-rater agreement was found to be almost perfect across all muscles, except for the multifidus muscle. When clinical examination findings were included for these muscles, quadratus lumborum (QL) degradation was found in both right-side (p = 0.017) and left-side (p = 0.002) leg involvement. Conclusions: QL muscle deterioration may serve as a diagnostic marker for PPS, potentially guiding lumbar pain treatment through rehabilitation.

Role of End Plate Changes and Paraspinal Muscle Pathology in Lower Back Pain: A Narrative Review.

Degenerative changes of the lumbar intervertebral disc are the most significant causes of enduring lower back pain. The possibility of the diagnosis is limited in people with this low back pain. Therefore, it is essential to identify the relevant back pain subgroups. The paraspinal muscles, that is, the muscles that attach to the spine, are necessary for the proper functioning of the spine and the body; insufficiency can result in back pain. Lower back pain disorders are strongly associated with altered function or structure of these paraspinal muscles, especially fibrosis and fatty infiltration. Modic changes are the bone marrow changes of the end plate in the vertebral body seen on MRI. These are strongly related to degeneration of the disc and are common in individuals with back pain symptoms. Articles were selected from Google Scholar using the terms 'Modic changes,' 'end plate changes,' 'paraspinal muscles,' and 'lower back pain. ' This article compiled different studies aiming to enhance the comprehension of biochemical processes resulting in the development of lumbar pain. Search using the keywords 'Modic changes,'' end plate changes lower back pain,' 'paraspinal muscles lower back pain,' and 'Modic changes lower back pain' on Google Scholar yielded 33000, 41000, 49400, and 17,800 results, and 958, 118, 890 and 560 results on Pubmed respectively.

Precision Rehabilitation After Neurostimulation Implantation for Multifidus Dysfunction in Nociceptive Mechanical Chronic Low Back Pain.

Chronic low back pain (CLBP) is a debilitating, painful, and costly condition. Implantable neuromuscular electrical stimulation targeting the multifidus musculature is growing as a non-pharmacologic option for patients with recalcitrant nociceptive mechanical CLBP who have failed conservative treatments (including medications and physical therapy) and for whom surgery is not indicated. Properly selecting patients who meet specific criteria (based on historical results from randomized controlled trials), who diligently adhere to implant usage and precisely implement neuromuscular rehabilitation, improve success of significant functional recovery, as well as pain medication reductions. Patients with nociceptive mechanical CLBP who underwent implanted multifidus neurostimulation have been treated by physicians and rehabilitation specialists who have honed their experience working with multifidus neurostimulation. They have collaborated on consensus and evidence-driven guidelines to improve quality outcomes and to assist providers when encountering patients with this device. Physicians and physical therapists together provide precision patient-centric medical management with quality neuromuscular rehabilitation to encourage patients to be experts of both their implants and quality spine motion to help override long-standing multifidus dysfunction related to their CLBP.

Relation of bone mineral density with fat infiltration of paraspinal muscles: The Goutallier classification.

Objectives: Muscle and bone tissue are interrelated throughout their developmental processes via paracrine and endocrine pathways. Osteosarcopenia has emerged with the growing data proving the high rate of simultaneous occurrence of sarcopenia and osteoporosis. We aimed to evaluate the relationship between osteoporosis, and muscle quality by grading the fatty infiltration in paraspinal muscles according to the Goutallier classification in magnetic resonance imaging (MRI). Methods: Data of postmenopausal patients who underwent MRI for low back pain were analyzed retrospectively. Lumbar spine and femoral neck bone mineral density (BMD) were measured by using dual energy X-ray absorptiometry (DXA). Grade of paraspinal muscle fatty infiltration for each level of lumbar vertebrae including L1-L2, L2-L3, L3-L4, was evaluated separately according to Goutallier classification system. Results: A total of 91 postmenopausal women were included in the study. The mean age of the study population was 60.5 ± 11. Lumbar vertebrae L1-L4 total T-scores and BMD g/cm2 were lower in patients with higher grades of Goutallier classification (P = 0.031 and P = 0.023, respectively). The distribution of the severity of fatty degeneration was significantly higher in the osteoporosis/osteopenia group at all 3 disc levels. No significant correlation was observed between femoral neck BMD and paraspinal muscle fat infiltration. Conclusions: There is a strong relationship between osteoporosis of the lumbar spine and paraspinal muscle quality, which can be considered as a reflection of osteosarcopenia. The Goutailler classification can be an effective and easy method in the evaluation of muscle quality with MRI.

Association of MRI findings with paraspinal muscles fat infiltration at lower lumbar levels in patients with chronic low back pain: a multicenter prospective study.

OBJECTIVE: In chronic low back pain (CLBP), the relationship between spinal pathologies and paraspinal muscles fat infiltration remains unclear. This study aims to evaluate the relationship between MRI findings and paraspinal muscles morphology and fat infiltration in CLBP patients by quantitative MRI. METHODS: All the CLBP patients were enrolled from July 2021 to December 2022 in four medical institutions. The cross-sectional area (CSA) and proton density fat fraction (PDFF) of the multifidus (MF) and erector spinae (ES) muscles at the central level of the L4/5 and L5/S1 intervertebral discs were measured. MRI findings included degenerative lumbar spondylolisthesis (DLS), intervertebral disc degeneration (IVDD), facet arthrosis, disc bulge or herniation, and disease duration. The relationship between MRI findings and the paraspinal muscles PDFF and CSA in CLBP patients was analyzed. RESULTS: A total of 493 CLBP patients were included in the study (198 females, 295 males), with an average age of 45.68 ± 12.91 years. Our research indicates that the number of MRI findings are correlated with the paraspinal muscles PDFF at the L4/5 level, but is not significant. Moreover, the grading of IVDD is the primary factor influencing the paraspinal muscles PDFF at the L4-S1 level (BES at L4/5=1.845, P < 0.05); DLS was a significant factor affecting the PDFF of MF at the L4/5 level (B = 4.774, P < 0.05). After including age, gender, and Body Mass Index (BMI) as control variables in the multivariable regression analysis, age has a significant positive impact on the paraspinal muscles PDFF at the L4-S1 level, with the largest AUC for ES PDFF at the L4/5 level (AUC = 0.646, cut-off value = 47.5), while males have lower PDFF compared to females. BMI has a positive impact on the ES PDFF only at the L4/5 level (AUC = 0.559, cut-off value = 24.535). CONCLUSION: The degree of paraspinal muscles fat infiltration in CLBP patients is related to the cumulative or synergistic effects of multiple factors, especially at the L4/L5 level. Although age and BMI are important factors affecting the degree of paraspinal muscles PDFF in CLBP patients, their diagnostic efficacy is moderate.

The morphological discrepancy of neuromuscular junctions between bilateral paraspinal muscles in patients with adolescent idiopathic scoliosis: A quantitative immunofluorescence assay.

Introduction: Prior studies suggested that neuromuscular factors might be involved in the pathogenesis of adolescent idiopathic scoliosis (AIS). The neuromuscular junction (NMJ) is the important pivot where the nervous system interacts with muscle fibers, but it has not been well characterized in the paraspinal muscles of AIS. This study aims to perform the quantitative morphological analysis of NMJs from paraspinal muscles of AIS. Methods: AIS patients who received surgery in our center were prospectively enrolled. Meanwhile, age-matched congenital scoliosis (CS) and non-scoliosis patients were also included as controls. Fresh samples of paraspinal muscles were harvested intraoperatively. NMJs were immunolabeled using different antibodies to reveal pre-synaptic neuronal architecture and post-synaptic motor endplates. A confocal microscope was used to acquire z-stack projections of NMJs images. Then, NMJs images were analyzed on maximum intensity projections using ImageJ software. The morphology of NMJs was quantitatively measured by a standardized 'NMJ-morph' workflow. A total of 21 variables were measured and compared between different groups. Results: A total of 15 AIS patients, 10 CS patients and 5 normal controls were enrolled initially. For AIS group, NMJs in the convex side of paraspinal muscles demonstrated obviously decreased overlap when compared with the concave side (34.27% ± 8.09% vs. 48.11% ± 10.31%, p = 0.0036). However, no variables showed statistical difference between both sides of paraspinal muscles in CS patients. In contrast with non-scoliosis controls, both sides of paraspinal muscles in AIS patients demonstrated significantly smaller muscle bundle diameters. Conclusions: This study first elucidated the morphological features of NMJs from paraspinal muscles of AIS patients. The NMJs in the convex side showed smaller overlap for AIS patients, but no difference was found in CS. This proved further evidence that neuromuscular factors might contribute to the mechanisms of AIS and could be considered as a novel potential therapeutic target for the treatment of progressive AIS.

Advances in the interaction between lumbar intervertebral disc degeneration and fat infiltration of paraspinal muscles: critical summarization, classification, and perspectives.

More than 619 million people in the world suffer from low back pain (LBP). As two potential inducers of LBP, intervertebral disc degeneration (IVDD) and fat infiltration of paraspinal muscles (PSMs) have attracted extensive attention in recent years. So far, only one review has been presented to summarize their relationship and relevant mechanisms. Nevertheless, it has several noticeable drawbacks, such as incomplete categorization and discussion, lack of practical proposals, etc. Consequently, this paper aims to systematically summarize and classify the interaction between IVDD and fat infiltration of PSMs, thus providing a one-stop search handbook for future studies. As a result, four mechanisms of IVDD leading to fat infiltration of PSMs and three mechanisms of fat infiltration in PSMs causing IVDD are thoroughly analyzed and summarized. The typical reseaches are tabulated and evaluated from four aspects, i.e., methods, conclusions, benefits, and drawbacks. We find that IVDD and fat infiltration of PSMs is a vicious cycle that can promote the occurrence and development of each other, ultimately leading to LBP and disability. Finally, eight perspectives are proposed for future in-depth research.

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.

The Differences on the Fatty Infiltration of Paraspinal Muscles between Single- and Multiple-level Intervertebral Disc Degeneration in Patients with Lumbar Disc Herniation.

OBJECTIVE: Multiple-level Intervertebral disc degeneration (IDD) in patients with lumbar disc herniation (LDH) is related to postoperative re-herniation and low back pain. Although many investigators believed that there is an interdependence between paraspinal muscles degeneration and IDD, few studies focused on the fatty infiltration of paraspinal muscles on single- and multiple-level IDD in patients with LDH. This study aims to investigate the difference on the fatty infiltration of paraspinal muscles between single- and multiple-levels IDD in patients with LDH. and to explore in patients with LDH whether fatty infiltration is a potential risk factor for multiple-level IDD. METHODS: This study was conducted as a retrospective observational analysis of 82 patients with LDH from January 1, 2020 to December 30, 2020 in our hospital were enrolled. Twenty-seven cases had single-level IDD (Group A), and 55 cases had multiple-level IDD (Group B). We measured the mean computed tomography (CT) density value of the paraspinal muscles, including multifidus (MF), erector spinae (ES) and psoas muscle (PM) at each disc from L1 to S1. Subgroups were set to further analyze the odds ratio (OR) of fatty infiltration of paraspinal muscles in different sex and BMI groups. We measured sagittal angles and analyzed the relationships between these angles and IDD. Finally, we use logistic regression, adjusted for other confounding factors, to investigate whether fatty infiltration is an independent risk factor for multi-level IDD. RESULTS: The average age in multi-level IDD (51.40 ± 15.47 years) was significantly higher than single-level IDD (33.37 ± 7.10 years). The mean CT density value of MF, ES and PM in single-level IDD was significantly higher than multi-level IDD (all ps < 0.001). There was no significant difference of the mean value of angles between the two groups. No matter being fat (body mass index [BMI] > 24.0 kg/m2) or normal, patients with low mean muscle CT density value of MF and ES are significantly easier to suffer from multiple-level IDD. In the pure model, the average CT density value of the MF, ES and PM is all significantly associated with the occurrence of multi-IDD. However, after adjusting for various confounding factors, only the OR of the average CT density value for MF and ES remains statistically significant (OR = 0.810, 0.834, respectively). CONCLUSIONS: In patients with LDH, patients with multiple-level IDD have more severe fatty infiltration of MF and ES than those with single-level IDD. Fatty infiltration of MF and ES are independent risk factors for multiple-level IDD in LDH patients.