Platelet-rich plasma does not accelerate the healing of damaged muscle following muscle strain.

Although platelet-rich plasma (PRP) has been widely used regardless of the severity of muscle strain, there have been very few basic studies in which its effects on muscle injury were examined by using models that accurately mimic the clinical muscle strain injury process. Therefore, the aim of this study was to confirm by physiological and structural analyses whether PRP purified by a general preparation method has a muscle healing effect on muscle damage caused by eccentric contraction (ECC). Male Wistar rats were subjected to muscle injury induced by ECC in bilateral plantar flexor muscles using electrical stimulation and an automatically dorsiflexing footplate. The rats were randomly assigned to three groups by type of injection: phosphate-buffered saline (PBS), leukocyte-poor PRP (LP-PRP), or leukocyte-rich PRP (LR-PRP) injection into gastrocnemius muscles three times at weekly intervals. The platelet concentrations of the LP-PRP and LR-PRP were three to five times higher than that of whole blood. The recovery process of torque strength in the plantar flexor muscle, signal changes in MRI images, and histological evaluation 3 weeks after injury showed no obvious differences among the three groups, and every muscle recovered well from the injury without marked fibrosis. The results that neither LP-PRP nor LR-PRP was found to accelerate healing of muscle injuries suggested that conventional preparation and use of PRP for simple muscle injuries caused by muscle strain should be carefully considered, and further basic research using models that accurately mimic clinical practice should be carried out to determine the optimal use of PRP.

Association of central sensitization, visceral fat, and surgical outcomes in lumbar spinal stenosis.

BACKGROUND: Controversy remains regarding predictors of surgical outcomes for patients with lumbar spinal stenosis (LSS). Pain sensitization may be an underlying mechanism contributing to LSS surgical outcomes. Further, obesity is associated with dissatisfaction and poorer outcomes after surgery for LSS. Therefore, this study aimed to examine the relationship between central sensitization (CS), visceral fat, and surgical outcomes in LSS. METHODS: Patients with LSS were categorized based on their central sensitization inventory (CSI) scores into low- (CSI < 40) and high- (CSI ≥ 40) CSI subgroups. The participants completed clinical outcome assessments preoperatively and 12 months postoperatively. RESULTS: Overall, 60 patients were enrolled in the study (28 men, 32 women; mean age: 62.1 ± 2.8 years). The high-CSI group had significantly higher mean low back pain (LBP), leg pain, and leg numbness visual analogue scale (VAS) scores than the low-CSI group (p < 0.01). The high-CSI group had a significantly higher mean visceral fat area than the low-CSI group (p < 0.01). Postoperatively, LBP VAS score was significantly worse in the high-CSI group. Relative to preoperatively, postoperative leg pain and leg numbness improved significantly in both groups. CONCLUSIONS: We believe that neuro decompression can be effective for LSS surgical outcomes in patients with CS; nonetheless, it should be approached with caution owing to the potential for worsening LBP. Additionally, visceral fat is an important indicator suggesting the involvement of CS.

Skeletal muscle endurance declines with impaired mitochondrial respiration and inadequate supply of acetyl-CoA during muscle fatigue in 5/6 nephrectomized rats.

Chronic kidney disease (CKD)-related cachexia increases the risks of reduced physical activity and mortality. However, the physiological phenotype of skeletal muscle fatigue and changes in intramuscular metabolites during muscle fatigue in CKD-related cachexia remain unclear. In the present study, we performed detailed muscle physiological evaluation, analysis of mitochondrial function, and comprehensive analysis of metabolic changes before and after muscle fatigue in a 5/6 nephrectomized rat model of CKD. Wistar rats were randomized to a sham-operation (Sham) group that served as a control group or a 5/6 nephrectomy (Nx) group. Eight weeks after the operation, in situ torque and force measurements in plantar flexor muscles in Nx rats using electrical stimulation revealed a significant decrease in muscle endurance during subacute phase related to mitochondrial function. Muscle mass was reduced without changes in the proportions of fiber type-specific myosin heavy chain isoforms in Nx rats. Pyruvate-malate-driven state 3 respiration in isolated mitochondria was impaired in Nx rats. Protein expression levels of mitochondrial respiratory chain complexes III and V were decreased in Nx rats. Metabolome analysis revealed that the increased supply of acetyl CoA in response to fatigue was blunted in Nx rats. These findings suggest that CKD deteriorates skeletal muscle endurance in association with mitochondrial dysfunction and inadequate supply of acetyl-CoA during muscle fatigue.NEW & NOTEWORTHY Mitochondrial dysfunction is associated with decreased skeletal muscle endurance in chronic kidney disease (CKD), but the muscle physiological phenotype and major changes in intramuscular metabolites during muscle fatigue in CKD-related cachexia remain unclear. By using a 5/6 nephrectomized CKD rat model, the present study revealed that CKD is associated with reduced tetanic force in response to repetitive stimuli in a subacute phase, impaired mitochondrial respiration, and inadequate supply of acetyl-CoA during muscle fatigue.

Does the L4 nerve root extend during femoral nerve stretch test? A cadaveric study of four cases analyzing the extension rates of the lumbar nerve root.

BACKGROUND: Lumbar radicular pain is a common symptom of lumbar disc herniation and spinal canal stenosis, and L4 nerve root impingement is difficult to diagnose. This study aimed to elucidate the extension rate of L4 nerve roots in Thiel-embalmed specimens using both classic and new femoral nerve stretch test (FNST), as well as straight leg raising test (SLRT). Additionally, the extension rate of the L2 and L3 nerve roots and L5 and S1 roots were determined using FNST (both classic and new) and SLRT, respectively. METHODS: Four Thiel-embalmed specimens were used. The extension rate data of the nerve root were obtained using a displacement sensor under the following conditions: knee joint flexed to 0°/45°/90°/135° with either the hip extension/flexion of 0° (classic FNST) or extension of 15° (new FNST); and hip joint flexed to 0°/30°/60°/90° with the knee flexion of 0° (SLRT). RESULTS: Case A had almost no L4 nerve root lengthening at 45° and 90° knee joint flexion; however, at 135° of knee flexion, the nerve root was lengthened. In Case B, the L4 nerve root was hardly extended by the classic FNST, but it was extended at 135° of knee flexion and 15° of hip extension. In Case C, the L4 nerve root showed little change by classic FNST and it was shortened by new FNST, whereas, it was extended by SLRT. Case D showed a shortened L4 nerve root at 135° of knee flexion in classic FNST and at 0°/45°/90°/135° of knee flexion and 15° of hip extension. Further, no root shortening was observed for L2 and L3 nerve roots according to both classic and new FNST. In contrast, the extension of L2 and L3 nerve root with the new FNST was high. In all cases, nerve roots were lengthened by the SLRT. Further, as the hip flexion angle increased, the rate of nerve elongation also increased. CONCLUSIONS: It was shown that in patients in whom L4 nerve root was extended by FNST, it was shortened by SLRT. The opposite pattern was also observed. Further, it is believed that FNST and SLRT are reliable tests for L2 and L3 radiculopathy and L5 and S1 radiculopathy, respectively, and that more tension on the femoral and sciatic nerves is better. Furthermore, we recommend that FNST should be performed with 15° hip extension and 135° knee flexion to improve the diagnostic accuracy.

Broad and Asymmetric Lower Extremity Myotomes: Results from Intraoperative Direct Electrical Stimulation of the Lumbosacral Spinal Roots.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: This study aimed to accurately map the lower extremity muscles innervated by the lumbar spinal roots by directly stimulating the spinal roots during surgery. SUMMARY OF BACKGROUND DATA: Innervation of the spinal roots in the lower extremities has been estimated by clinical studies, anatomical studies, and animal experiments. However, there have been discrepancies between studies. Moreover, there are no studies that have studied the laterality of lower limb innervation. MATERIALS AND METHODS: In 73 patients with lumbar degenerative disease, a total of 147 spinal roots were electrically stimulated and the electromyographic response was recorded at the vastus medialis (VM), gluteus medius (GM), tibialis anterior (TA), biceps femoris (BF), and gastrocnemius (GC). The asymmetry index (AI) was obtained using the following equation to represent the left-right asymmetry in the CMAP amplitude. Paired t-tests were used to compare CMAP amplitudes on the right and left sides. Differences in the AI among the same spinal root groups were determined using one-way analysis of variance. RESULTS: The frequency of compound muscle action potentials (CMAP) elicitation in VM, GM, TA, BF, and GC were 100%, 75.0%, 50.0%, 83.3%, and 33.3% in L3 spinal root stimulation, 90.4%, 78.8%, 59.6%, 73.1%, and 59.6% in L4 spinal root stimulation, 32.2%, 78.0%, 93.2%, 69.5%, and 83.1% in L5 spinal root stimulation, and 40.0%, 100%, 80.0%, 70.0%, and 80.0% in S1 spinal root stimulation, respectively. The most frequent muscle with maximum amplitude of the CMAP in L3, L4, L5, and S1 spinal root stimulation was the VM, GM, TA, and GM respectively. Unilateral innervation occurred at high rates in the TA in L4 root stimulation and the VM in L5 root stimulation in 37.5% and 42.3% of patients, respectively. Even in patients with bilateral innervation, a 20-38% asymmetry index of CMAP amplitude was observed. CONCLUSIONS: The spinal roots innervated a much larger range of muscles than what is indicated in general textbooks. Furthermore, a non-negligible number of patients showed asymmetrical innervation of lower limb by the lumbar spinal roots.

Evaluation of segmental mobility in patients with lumbar spondylolisthesis : A comparison of images from standing flexion-extension and standing/supine slippage.

PURPOSE: To evaluate segmental mobility with degenerative lumbar spondylolisthesis (DLS), upright lateral flexion-extension radiographs (FE) are widely used. However, some authors have described that a combination of lateral radiographs in the standing position and supine sagittal image (SS) reveal more segmental mobility than FE. The purpose of this study was to investigate the optimal method for evaluating segmental mobility with DLS. METHODS: We included 92 consecutive Japanese patients diagnosed with DLS. Sagittal translation (ST) determined by FE and SS were compared. Pathological instability was defined as ST more than 8% of the upper vertebra. Patients were divided into those diagnosed with pathological instability in FE (PI-FE) and those diagnosed with SS (PI-SS), and lumbar lordosis (LL) in the standing position in each group were compared. RESULTS: ST in FE was significantly greater than in SS. Of 92 patients, 31 had pathological instability in FE or SS ; 17 patients had PI-FE, and 10 patients had PI-SS. LL in the standing position in PI-FE was significantly smaller than in PI-SS. CONCLUSIONS: ST in FE was greater than that in SS, contrary to previous studies' reports on Caucasians. Since Japanese individuals have smaller LL than Caucasians, FE tends to reveal more segmental mobility than SS. J. Med. Invest. 70 : 135-139, February, 2023.

Intravoxel Incoherent Motion Factors Affecting Collapse and Nonunion of Osteoporotic Vertebral Fracture.

STUDY DESIGN: Longitudinal study. OBJECTIVES: Intravoxel incoherent motion (IVIM), a magnetic resonance imaging (MRI) scanning technique that applies diffusion-weighted imaging (DWI), is effective for the quantitative assessment of malignant tumors of the vertebral bone. We hypothesized that IVIM parameters of vertebral bodies are associated with the prognosis of osteoporotic vertebral fracture (OVF). We aimed to explore the relationships between IVIM parameters for vertebral collapse and non-union after OVF and calculate the cut-off values of these parameters for vertebral collapse and non-union. METHODS: A total of 150 patients with acute OVF (150 women; mean age: 79.1 ± 7.4 years) were included and treated conservatively with bracing. MRI was performed at the time of injury. IVIM parameters, such as apparent diffusion coefficient (ADC), molecular diffusion coefficient (D), and perfusion-related diffusion (D*) were recorded. The patients were classified into 3 groups: low-collapse (height loss of ≤50%), high-collapse (height loss of >50%), and non-union. We compared ADC, D, and D* among the low-collapse, high-collapse, and non-union groups and performed a receiver operating characteristic (ROC) curve analysis to determine the boundary values of the high-collapse and non-union groups. RESULTS: The low-collapse, high-collapse, and non-union groups had no significant differences in ADC and D. However, D* differed significantly among the 3 groups. ROC analysis revealed cut-off values of 19.0 × 10-3 mm2/s and 12.3 × 10-3 mm2/s for the high-collapse and non-union groups, respectively. CONCLUSIONS: D* is a significant prognostic indicator for high-collapse and non-union groups with OVF. This suggests that D* should be considered when assessing OVF.

T1rho, T2, and T2* relaxation time based on grading of intervertebral disc degeneration.

BACKGROUND: Previous studies have explored the biochemical changes of disc degeneration and its relevance in low back pain using various quantitative magnetic resonance imaging (MRI) techniques. However, quantitative evaluation of intervertebral disc (IVD) with MRI such as T1rho, T2, and T2* have not been previously analyzed and compared directly in the same patients. PURPOSE: To investigate T1rho, T2, and T2* of IVD degeneration in the same patients, reveal the correlation coefficients of these values, and evaluate which values are more sensitive to detect the degree of IVD degeneration. MATERIAL AND METHODS: The participants were 55 patients who underwent MRI examinations which the investigator classified the degree of IVD degeneration according to the Pfirrmann classification. The T1rho, T2, and T2* values of IVD were analyzed for their classification and were compared. RESULTS: T1rho, T2, and T2* values were 74.3 ± 7.1, 61.2 ± 6.7, and 46.5 ± 16.3 ms (grade II); 61.6 ± 11.8, 48.9 ± 8.2, and 34.1 ± 11.8 ms (grade III); 50.8 ± 10.8, 38.9 ± 9.8, and 25.4 ± 8.1 ms, (grade IV); 44.5 ± 13.3, 34.8 ± 9.5, and 11.2 ± 6.6 ms (grade V), respectively. Those values significantly decreased with increasing grades, but T1rho and T2 values for grades IV and V were not different. CONCLUSION: The T1rho and T2 values were excellent for the evaluation of initial to moderate IVD degeneration with water and proteoglycan content. In contrast, the T2* value was suitable for detailed evaluation of progressive IVD, even with poor water content.

Degenerative Lumbar Spondylolisthesis Patients With Movement-related Low Back Pain Have Less Postoperative Satisfaction After Decompression Alone.

STUDY DESIGN: Retrospective analysis of prospectively collected multicenter observational data. OBJECTIVE: The aim was to examine the preoperative factors affecting postoperative satisfaction following posterior lumbar interbody fusion (PLIF) and microendoscopic muscle-preserving interlaminar decompression (ME-MILD) in patients with degenerative lumbar spondylolisthesis (DLS). SUMMARY OF BACKGROUND DATA: The technique involved in DLS surgery may either be decompression alone or decompression-fixation. Poor performance may occur after either of these surgical treatments. The author hypothesized that evaluating the correlation between preoperative quality of life and postoperative performance would aid in determining the optimal procedure. MATERIALS AND METHODS: This study included 138 patients who underwent surgery for 1-level mild DLS. The authors performed PLIF for 79 patients and ME-MILD for 59 patients. When the satisfaction subscale of the Zurich Claudication Questionnaire exceeded 2 points, postoperative satisfaction was considered poor. The clinical characteristics were investigated. Responses to preoperative health-related quality of life questionnaires, such as the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ), short form-36 health survey (SF-36), and visual analog scale, were compared between the satisfied and unsatisfied groups. RESULTS: In the PLIF group, no endogenous factors influenced postoperative satisfaction. The ME-MILD cohort's satisfied and unsatisfied patients differed significantly in terms of preoperative lumbar spine dysfunction ( P <0.001) items of the JOABPEQ, role physical ( P =0.03), and role emotional ( P =0.03) items of the SF-36. A strong correlation ( r =-0.609 P =0.015) was found between preoperative lumbar spine dysfunction and postoperative satisfaction. CONCLUSIONS: In the ME-MILD group, preoperative lumbar spine function was correlated with postoperative satisfaction. Decompression alone may be ineffective in cases with decreased lumbar spine function prior to surgery. The degree of low back pain on movement should be considered before selecting the surgical method. LEVEL OF EVIDENCE: 3.

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.

Ultrastructural Assessment and Proteomic Analysis in Myofibrillogenesis in the Heart Primordium After Heartbeat Initiation in Rats.

Myofibrillogenesis is an essential process for cardiogenesis and is closely related to excitation-contraction coupling and the maintenance of heartbeat. It remains unclear whether the formation of myofibrils and sarcomeres is associated with heartbeat initiation in the early embryonic heart development. Here, we investigated the association between the ultrastructure of myofibrils assessed by transmission electron microscopy and their proteomic profiling assessed by data-independent acquisition mass spectrometry (DIA-MS) in the rat heart primordia before and after heartbeat initiation at embryonic day 10.0, when heartbeat begins in rats, and in the primitive heart tube at embryonic day 11.0. Bundles of myofilaments were scattered in a few cells of the heart primordium after heartbeat initiation, whereas there were no typical sarcomeres in the heart primordia both before and after heartbeat initiation. Sarcomeres with Z-lines were identified in cells of the primitive heart tube, though myofilaments were not aligned. DIA-MS proteome analysis revealed that only 43 proteins were significantly upregulated by more than 2.0 fold among a total of 7,762 detected proteins in the heart primordium after heartbeat initiation compared with that before heartbeat initiation. Indeed, of those upregulated proteins, 12 (27.9%) were constituent proteins of myofibrils and 10 (23.3%) were proteins that were accessories and regulators for myofibrillogenesis, suggesting that upregulated proteins that are associated with heartbeat initiation were enriched in myofibrillogenesis. Collectively, our results suggest that the establishment of heartbeat is induced by development of bundles of myofilaments with upregulated proteins associated with myofibrillogensis, whereas sarcomeres are not required for the initial heartbeat.

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.

Effect of Minimally Invasive Selective Laminectomy for Cervical Spondylotic Myelopathy on Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective analysis of prospectively collected observational data. OBJECTIVE: This study aimed to evaluate the slippage, sagittal alignment, and range of motion (ROM) after selective laminectomy (SL) in patients who had cervical spondylotic myelopathy (CSM) with degenerative spondylolisthesis (DS). SUMMARY OF BACKGROUND DATA: Clinical outcomes have been reported for both decompression and fusion surgeries for DS of the lumbar spine. However, only a few reports have examined cervical spine spondylolisthesis. MATERIALS AND METHODS: This study included 178 patients who underwent SL for CSM. Those with ossification of the posterior longitudinal ligament were excluded. Slippage >2 mm was defined as spondylolisthesis, and spondylolisthesis progression was defined as an additional displacement >2 mm on a neutral radiograph. The slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were examined before and ≥2 years after surgery. Radiologic parameters were evaluated according to the slip direction and the number of laminae removed. RESULTS: DS was observed in 29 patients (16.3%); 24 patients, comprising 9 and 15 in the anterolisthesis and retrolisthesis groups, respectively, were successfully followed up for more than 2 years. Preoperative and postoperative radiologic changes in slippage, translational motion, C2-C7 angle, local kyphosis, and ROM were not remarkable in either group regardless of the number of laminae removed. Revision surgery for the progression of DS and alignment deterioration was not required in any patient of either group. CONCLUSIONS: SL does not affect DS, sagittal alignment, or ROM irrespective of the slip direction and the number of laminae removed, even after >2 years after surgery. Given the preservation of the posterior elements, SL may be an effective treatment for CSM with DS. LEVEL OF EVIDENCE: Level IV.

Optimal acceleration factor for image acquisition in turbo spin echo: diffusion-weighted imaging with compressed sensing.

In this study, the change in the image quality and apparent diffusion coefficient (ADC) with increase in the acceleration factor (AF) was analyzed and the most optimal AF was determined to reduce the scan time while preserving the image quality. The AF was changed from 2 to 20 in the MR acquisitions. The similarities between the accelerated and reference images were determined based on the structural similarity (SSIM) index for DWI image and coefficient of variation (%CV) for ADC. The SSIM index decreased significantly when the AF ≥ 8 compared with when the AF = 2 (p < 0.05). In the reference image, the %CV of the ADC increased significantly when the AF ≥ 10 (p < 0.01). In conclusion, a remarkable decrease in the image quality and ADC was observed when the AF was > 8. Thus, an AF < 8 would be optimal for reducing the scan time while preserving the image quality.

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.

Association between Spinopelvic Alignment and Lumbar Intervertebral Disc Degeneration Quantified with Magnetic Resonance Imaging T2 Mapping in Patients with Chronic Low Back Pain.

INTRODUCTION: Although intervertebral disc degeneration (IVDD) and spinopelvic malalignment are likely key structural features of spinal degeneration and chronic low back pain (CLBP), the correlation analysis has not been fully conducted. This cross-sectional quantitative magnetic resonance imaging (MRI) T2 mapping study aimed to elucidate the association between IVDD and spinopelvic alignment in CLBP patients. METHODS: The subjects included 45 CLBP patients (19 men and 26 women; mean age, 63.8 ± 2.0 years; range, 41-79 years). The T2 values of the anterior annulus fibrosus (AF), the nucleus pulposus (NP), and the posterior AF were evaluated using MRI T2 mapping. We compared the possible correlations of spinopelvic parameters with T2 values of anterior AF, NP, and posterior AF using Pearson's correlation coefficient analysis. T2 values in these regions were classified into upper (L1-L2 and L2-L3), middle (L3-L4), and lower (L4-L5 and L5-S1) disc levels, and we analyzed the correlations with spinopelvic parameters. RESULTS: There were significant correlations of the anterior AF T2 values with lumbar lordosis (r = 0.51, p < 0.01), sacral slope (r = 0.43, p < 0.01), sagittal vertical axis (r = -0.40, p < 0.01), and pelvic tilt (r = -0.33, p < 0.01). In all lumbar levels, T2 values of anterior AF had significantly positive correlation with LL and significantly negative correlation with SVA. In lower disc level, T2 values of anterior AF had significantly positive correlation with SS and significantly negative correlation with PT. T2 values of NP and posterior AF had no significant correlations with spinopelvic parameters in all lumbar disc levels. CONCLUSIONS: In summary, this study indicated that the anterior AF degeneration is associated with hypolordosis of the lumbar spine, anterior translation of the body trunk, and posterior inclination of the pelvis in CLBP. Anterior AF degeneration in all lumbar disc levels was associated with hypolordosis of the lumbar spine and anterior translation of the body trunk. Anterior AF degeneration in lower disc level was associated with posterior inclination of the pelvis.

Relevance between Schmorl's Node and Lumbar Intervertebral Disc Degeneration Quantified with Magnetic Resonance Imaging T2 Mapping in Chronic Low Back Pain.

STUDY DESIGN: Cross-sectional study. PURPOSE: The purpose of this study was to elucidate the relevance among Schmorl's node (SN), chronic low back pain (CLBP), and intervertebral disc degeneration (IVDD) with the use of magnetic resonance imaging T2 mapping. OVERVIEW OF LITERATURE: SN may be combined with CLBP and/or IVDD; however, their relationship has not been determined to date. METHODS: A total of 105 subjects were included (48 men and 57 women; mean age, 63.2±2.7 years; range, 22-84 years). We analyzed five functional spinal unit levels (L1-S1) and evaluated the T2 values of the anterior annulus fibrosus (AF), nucleus pulposus, and posterior AF. We compared the low back pain (LBP) Visual Analog Scale (VAS) scores and the T2 values in each decade with or without SN. RESULTS: There were no remarkable differences in SN prevalence rate regarding age decade or gender. SNs were more prevalent in the upper 2 levels (70.3%). LBP VAS scores with and without SN were 64.7±4.3 mm and 61.9±2.8 mm, respectively, with no significant differences between the groups (p=0.62). The T2 values of anterior AF with SN were significantly lower than those without SN in patients in their 50s, 60s, 70s, and 80s (p<0.01). CONCLUSIONS: SN presence is not itself a risk factor for CLBP; however, it indicates IVDD of the anterior AF in subjects with SN who are ≥50 years old.