Modeling thoracolumbar fascia mechanical tensile behavior with microstructure-level descriptors.

Sensory nerve fibers containing calcitonin gene-related peptide in gastrocnemius, latissimus dorsi and erector spinae muscles and thoracolumbar fascia in mice

The quantitative assessment of individual muscle and fascial stiffness in patients with low back pain remains a challenge. This study aimed to compare the stiffness of the thoracolumbar fascia (TLF), erector spinae (ES), and multifidus (MF) in patients with and without chronic non-specific low back pain (CNLBP) using shear wave elastography (SWE). It also sought to explore the relationship between muscle and fascial stiffness and the levels of pain and dysfunction in patients with CNLBP. In this cross-sectional study, 30 patients with CNLBP (age 27.40 ± 4.57 years, 19 males, 11 females, BMI 22.96 ± 2.55kg/m2) and 32 healthy controls (age 27.94 ± 4.94 years, 15 males, 17 females, BMI 22.52 ± 2.26kg/m2) were enrolled. Stiffness of the TLF, ES, and MF was measured using SWE, and Young's modulus values were recorded. The numeric rating scale (NRS) for quantifying pain intensity and the Oswestry Disability Index (ODI) scores were recorded for the case group to examine their correlations with the resilience index. The CNLBP group exhibited significantly higher shear modulus values at the L4-5 bilateral TLF (left: p = 0.014, d = 0.64; right: p = 0.002, d = 0.86), ES (left: p = 0.013, d = 0.66; right: p = 0.027, d = 0.58), and MF (left: p = 0.009, d = 0.69; right: p = 0.002, d = 0.85) compared to the control group. Comparable findings were observed for the right ES (p = 0.026, d = 0.59) and left MF (p = 0.020, η 2 = 0.09) at L1-2. Strong correlations were observed between the shear modulus of the bilateral TLF (left: r = 0.57, p = 0.001; right: r = 0.65, p < 0.001) at L4-5 and the NRS scores. Moderate correlations were noted between the shear modulus of the ES (left: r = 0.42, p = 0.022; right: r = 0.48, p = 0.007) and MF (left: r = 0.50, p = 0.005; right: r = 0.42, p = 0.023) at L4-5 and the NRS scores. Additionally, the shear modulus of the MF (r = 0.50, p = 0.005) on the left side of L1-2 showed similar correlations. Strong correlations were observed between the shear modulus of the bilateral TLF (left: r = 0.60, p < 0.001; right: r = 0.58, p < 0.001) at L4-5 and the ODI scores. Moderate correlations were observed between the shear modulus of the right TLF (r = 0.43, p = 0.017), ES (r = 0.38, p = 0.037), and MF (r = 0.44, p = 0.015) at L1-2, as well as the bilateral MF (left: r = 0.46, p = 0.011; right: r = 0.45, p = 0.012) at L4-5, and the ODI scores. No significant correlations were found at other measurement sites. In patients with CNLBP, the stiffness of the lumbar fascia and muscles is generally higher than in individuals without LBP. However, this increase is not uniform across all lumbar regions, with the most significant changes observed in the L4-5 segments. In addition, higher stiffness may be associated with pain and dysfunction, primarily manifested in the TLF.

The low back and the lower limb are generally viewed as two isolated regions, however, there are many authors who believe that these two regions are functionally related. This is due to the two regions being connected to each other through the kinematic chain of the lower extremity. The lumbar spine is the link between the lower extremities and the trunk, and plays a significant role in the transfer of forces through the body via the kinematic chain. The physical link between the low back and the lower limb is supplied by the thoracolumbar fascia, which plays an important role in the transfer of forces between the spine, pelvis and legs. Although a relationship between the lower extremity and low back pain is often assumed, little research has been published to demonstrate the association. Most of the evidence so far has been anecdotal, without scientific research to support it. This study was designed to compare the relative effectiveness of lumbar spine manipulation, compared to combined lumbar spine and subtalar manipulation for the treatment of chronic mechanical low back pain, using subjective and objective measures, for the management of chronic mechanical low back pain. The study design was a quantitative clinical trial, using purposive sampling. It consisted of forty voluntary participants with chronic mechanical low back pain. There were two groups of twenty participants each, each of whom received six treatments within a three week period. Group A received manipulation of the lumbar spine only, whilst Group B received manipulation of both the lumbar spine and subtalar joint. The outcome measures included the response of the participants to the Numerical Pain Rating Scale-101 and the Quebec Low Back Pain and Disability Questionnaire. Objective data was obtained from three digital Algometer measures. Data was collected prior to the initial, third and sixth treatment. iv Statistically both groups showed improvements, subjectively and objectively, with regards to chronic mechanical low back pain. Inter-group testing for NRS over time showed no significant effect for both treatment groups. There was a significant treatment effect for Algometer Average TP1 while the treatment effect for Algometer Average TP2 was not significant. However, inter-group testing for the Quebec LBP over time showed no significant effect for both treatment groups. Inter-group analysis demonstrated no statistical significance between the two groups for subjective and objective measurements, thus suggesting that there is no additional benefit in treating the subtalar joint in the management of mechanical low back pain. Further studies will also benefit greatly from the use of larger sample sizes to improve statistical relevance of data.

The aim of this work is to demonstrate how the chronicity of low back pain can modify the trophism of the paraspinal muscles, by performing an ultrasound and MRI evaluation of the paraspinal muscles in the lumbar spine and correlating it to the time of onset of low back pain. An ultrasound evaluation was carried out in the lumbar area with a 5-17MHz linear probe of the paraspinal muscles of the lumbar region, compared with the MRI of the lumbar spine, in patients presented to our attention for chronic low back pain (> 6months), from January 2021 to January 2023. In each patient, two series of images were analyzed, in the coronal and sagittal planes. Between January 2021 and January 2023, a total of 79 patients were retrospectively evaluated by ultrasound for chronic low back pain. The patients, including 46 men and 33 women, had an average age of 51.6years (min 24-max 74). In the evaluation of the profile of the paravertebral muscles, 22 patients (27.8%) showed hypotrophy of the paravertebral muscles with a concave profile, while the measurement of the thickness of the fascia showed an average thickness of 2.19mm with a range between 1, 3 and 3.2mm and an interquartile range of 1.7-2.65mm. 77.2% of patients with a concave profile showed a thickness of the FTL > 2.5mm, and an average duration of symptoms of approximately 15.3months, to demonstrate a correlation between muscle hypotrophy, thickness of the FTL and duration of onset of symptoms. In the evaluation of chronic low back pain carried out with MRI and ultrasound, the paravertebral musculature profile and the thickness of the thoracolumbar fascia are two instrumental data which, associated with the proposed classification and correlated to the clinical picture, allow to determine the chronicity of the pathological picture.

Variation in the insertion of the latissimus dorsi & its clinical importance

The mechanisms underlying individual variability in acupuncture analgesia among patients with chronic pain remain unclear. This randomized controlled trial investigated the core mechanisms of differential responses to acupuncture from genetic, neuroimaging, and transcriptomic perspectives in patients with chronic pain due to knee osteoarthritis (KOA). A total of 180 KOA chronic knee pain patients were randomly assigned to verum acupuncture (VA), sham acupuncture (SA), celecoxib (SC), placebo (PB), or waiting list (WL) groups (36 each). Over 2 weeks, VA/SA received 10 sessions, SC/PB oral medication for 14 days, and WL no intervention. Baseline 3.0T MRI 3D-T1 scans and genotyping (GABRB3 rs4906902, OPRM1 rs1799971, COMT rs4680, BDNF rs6265) were performed. Efficacy was assessed via VAS and WOMAC; responders/non-responders were defined by minimally clinically important difference. Chi-square test, logistic regression, voxel-based morphometry (VBM), and Allen Human Brain Atlas-based partial least squares regression were used. No significant difference in primary outcomes was observed between VA and SA, so they were combined as the acupuncture group (AG) to enhance statistical power. Only AG had a significant association between GABRB3 rs4906902 AG/GG genotype and acupuncture response (p < 0.05); other loci showed no correlation. AG/GG carriers in AG had lower gray matter volume in caudate head, putamen, and ventral striatum, with higher GABRB3 expression in these regions. Genetic polymorphisms at GABRB3 rs4906902 could influence the analgesic effect of acupuncture treatment in patients with KOA chronic knee pain, with AG/GG genotype carriers exhibiting superior analgesic effects. This finding may be associated with pain-modulating brain regions' gray matter volume reduction and upregulation of GABRB3 gene expression.

The thoracolumbar fascia (TLF) and the erector spinae aponeurosis (ESA) play an important role in the biomechanics of the spine and could be a source of low back pain. Although the TLF and ESA are key structures in several musculoskeletal dysfunctions and in tissue engineering, there is still a lack of evidence in the literature to prove that they have different mechanical properties and roles when considered as a single tissue. Furthermore, no methods are currently available to study these structures in vivo. The objective of this study was to analyze the ex-vivo tensile properties TLF and ESA, and to test the potential of ultrasound shearwave elastography (SWE) to characterize these tissues. Hundred samples from N=10 fresh-frozen human donors were studied. Shear wave speed (SWS) was measured in all samples with SWE, and their tensile properties were measured with mechanical testing. Results show that TLF is anisotropic, and more compliant than ESA. SWS was not significantly correlated to tensile moduli. These findings could potentially aid surgeons in their daily practices, assist engineers with in silico simulations, and support physiotherapists in musculoskeletal rehabilitation by enabling them to customize medical interventions for each specific patient and clinical condition. However, further research is necessary to further investigate the behavior in terms of time-dependent response and link between the tissue anisotropy and microstructural organization.

Introduction. Lumbosacral dysfunctions and the resulting pain syndromes, such as low-back pain (LBP), are one of the most common musculoskeletal problems being faced by society around the world. So far, a contributory role of thoracolumbar fascia (TLF) dysfunction in some cases of LBP has been suggested. Research also confirms that muscle resting activity level in the TLF area is increased in people with LBP. Myofascial release (MFR) is a therapeutic option offered to patients with chronic low-back pain (CLBP). The therapy aims to improve flexibility and sliding between layers of soft tissue, and thus decrease muscle activity, reduce pain intensity, and improve functional performance. Objective. This study aims to assess changes in resting activity of selected muscles within the TLF in a group of patients with CLBP immediately after a single MFR treatment and one month after the intervention. Methods. A total of 113 patients with CLBP completed the study. Simple randomization was applied to assign subjects to study groups. The experimental group (n = 59) underwent a single session of MFR therapy. No therapeutic intervention was applied to the control group (n = 54). Surface electromyography was used to evaluate positive treatment effects in patients immediately after receiving the therapy (experimental group) and after one month (experimental and control group). Results. A statistically reliable decrease in the activity of erector spinae (ES) and multifidus muscles (MF) was observed after a single session of MFR therapy. Effects of the treatment were present immediately after receiving the therapy and one month after the intervention. Conclusions. A single MFR treatment in patients with CLBP immediately reduces the resting activity levels of ES and MF. Results of measurements carried out one month after the treatment confirm that the therapeutic effects were maintained.

Background and Aim: Balance disorders are among common complications of chronic low back pain (LBP). Since the tissue and echo­genicity of thoracolumbar fascia changes in chro­nic LBP, the independent motion of fascia layers would negatively alter, and it may affect the con­trol of spine movements. It has been shown that myofascial release (MFR) improves the function of transversus abdominis as a core muscle in LBP. So, MFR may affect the balance and pos­tural control in these patients. The aim of this study was to evaluate the immediate effects of MFR and core stability (CS) exercises on dyna­mic balance and pain in women with chronic non-specific LBP. Methods: In this pilot study, with a pretest-posttest design, 10 females aged 30 ± 9.04 parti­cipated. The participants received one session of MFR on thoracolumbar fascia and CS exercises. The outcome measures were dynamic balance by Y balance test (YBT) and pain with visual ana­logue scale (VAS), which were assessed before and immediately after the intervention. Results: Dynamic balance improved signifi­cantly (p &lt; 0.02) after intervention. The VAS as an indicator of pain intensity showed significant improvement (p = 0.005). Conclusion: The application of MFR plus CS exercises for a single session is effective in improving dynamic balance and pain in women with chronic non-specific LBP. Keywords: Dynamic balance; core stability; low back pain; myofascial release

Although manual therapy for pain relief has been used as an adjunct in treatments for chronic low back pain (CLBP), there is still the belief that a single session of myofascial release would be effective. This study was a crossover clinical trial aimed to investigate whether a single session of a specific myofascial release technique reduces pain and disability in subjects with CLBP. 41 participants over 18 years old were randomly enrolled into 3 situations in a balanced and crossover manner: experimental, placebo, and control. The subjects underwent a single session of myofascial release on thoracolumbar fascia and the results were compared with the control and placebo groups. The outcomes, pain and functionality, were evaluated using the numerical pain rating scale (NPRS), pressure pain threshold (PPT), and Oswestry Disability Index (ODI). There were no effects between-tests, within-tests, nor for interaction of all the outcomes, i.e., NPRS (η 2 = 0.32, F = 0.48, p = 0.61), PPT (η2 = 0.73, F = 2.80, p = 0.06), ODI (η2 = 0.02, F = 0.02, p = 0.97). A single trial of a thoracolumbar myofascial release technique was not enough to reduce pain intensity and disability in subjects with CLBP.

Background: Chronic nonspecific low back pain (CNLBP) is often associated with impaired mobility, functional limitations, and psychological distress. While myofascial release (MFR) and capacitive-resistive therapy (TECAR) have individually shown potential benefits, evidence regarding their combined application is limited. Methods: This assessor-blinded, three-arm randomized controlled trial included 67 patients with CNLBP. Participants were assigned to MFR alone, resistive-mode TECAR (R-TECAR) alone, or MFR plus R-TECAR. Interventions were administered twice weekly for 4 weeks, with each session lasting 20 min. Primary outcomes included the Numeric Pain Rating Scale (NPRS) and the Roland-Morris Disability Questionnaire (RMDQ), assessed at the baseline, 4 weeks, and one-and-a-half-month follow-up. Secondary outcomes encompassed thoracolumbar fascia (TLF) thickness, pressure pain threshold (PPT), trunk mobility, quality of life, anxiety, and depression. Intention-to-treat analyses were performed. Results: All interventions yielded significant improvements in pain and disability over time, although the combined MFR + R-TECAR therapy did not achieve statistically significant additional benefits compared with single therapies. Notably, a significant interaction effect emerged for PPT in the right quadratus lumborum muscle (p=0.01), with the MFR + R-TECAR group demonstrating greater improvement than R-TECAR alone. Other secondary outcomes, including TLF thickness and psychometric measures, improved over time but showed no significant between-group differences. Conclusions: Combining MFR with R-TECAR for CNLBP did not produce superior outcomes compared with individual treatments though certain muscle-specific benefits were observed. Future research should focus on optimizing treatment parameters, extending intervention and follow-up periods, and exploring individualized approaches to maximize therapeutic efficacy. Trial Registration: Chinese Registry of Clinical Trials: ChiCTR2400087961.

The microstructural effects on the mechanical response of polycrystals: A comparative experimental-numerical study on conventionally and additively manufactured metallic materials

Intervertebral discs from spinal nondeformity and deformity patients have different mechanical and matrix properties

The dorsal horn of the spinal cord is the first central relay where nociceptive inputs are processed. Based on the expression and modulation of intrinsic electrophysiological properties in in vitro slice preparations, dorsal horn neurones (DHNs) display different discharge patterns (tonic, plateau or rhythmic), which shape the neurone's response to sensory inputs. However, it is unclear whether intrinsic properties play any role in sensory processing in vivo. Using in vivo patch clamp recordings in the adult rat, we here examine whether these intrinsic properties are present, and to what extent they determine the DHN response to natural stimulation. We focused primarily on wide dynamic range neurones in deep laminae. These cells displayed a multicomponent peripheral receptive field, comprising an excitatory firing zone, a low-probability firing fringe, and adjacent inhibitory zones. Deep DHNs presented similar intrinsic properties to those observed in vitro, including plateau potentials. These plateaus, underlying high frequency accelerating discharges and after-discharges, were triggered by mechanical stimulation of the excitatory receptive field. Persistent activities induced by activation of plateau potentials were interrupted by stimulation of peripheral inhibitory zones. Moreover, we show that plateau activation is necessary for the expression of windup in response to repetitive, nociceptive stimulation. Finally, using the spinal nerve ligation model of neuropathy, we demonstrate a significant increase in the proportion of plateau neurones in deep dorsal laminae. Our data, therefore, establish that intrinsic amplification properties are expressed within intact spinal circuits and suggest their involvement in neuropathy-induced hyperexcitability of deep DHNs.

Chronic Pain and Decreased Opioid Efficacy: An Inflammatory Link