Quantification of hyaluronan in human fasciae: variations with function and anatomical site

Fascial plane blocks: from microanatomy to clinical applications

PURPOSE OF REVIEW

In the last 20 years, advancements in the understanding of fasciae have significantly transformed anaesthesia and surgery. Fascial plane blocks (FPBs) have gained popularity due to their validated safety profile and relative ease. They are used in various clinical settings for surgical and nonsurgical indications. Growing evidence suggests a link between the microscopic anatomy of fasciae and their mechanism of action. As a result, knowledge of these aspects is urgently needed to better optimise pain management. The purpose of this review is to summarise the different microscopic aspects of deep/muscular fascia to expand our understanding in the performance of FPBs.

RECENT FINDINGS

There is ample evidence to support the role of FPBs in pain management. However, the exact mechanism of action remains unclear. Fasciae are composed of various structural elements and display complex anatomical characteristics at the microscopic level. They include various cell types embedded within an extracellular matrix abundant in collagens and hyaluronan. Increasingly, numerous studies demonstrated their innervation that contributes to their sensory functions and their role in proprioception, motor coordination and pain perception. Lastly, the diversity of the cellular and extracellular matrix, with their viscoelastic properties, is essential to understanding the FPBs' mechanism of action.

SUMMARY

Physicians must be aware of the role of fascial microscopic anatomy and better understand their properties to perform FPBs in a conscious manner and enhance pain management.

The Impact of Sciatic Nerve Injury on Extracellular Matrix of Lower Limb Muscle and Thoracolumbar Fascia: An Observational Study

Peripheral nerve injury (PNI) is a complex clinical challenge resulting in functional disability. Neurological recovery does not always ensure functional recovery, as extracellular matrix (ECM) alterations affect muscle function. This study evaluates hyaluronan (HA) and collagen concentration in the gastrocnemius muscle and thoracolumbar fascia (TLF) in unilateral lower limb PNI rats to explore systemic ECM alterations following PNI and their impacts on functional recovery. Eighteen 8-week-old male Sprague-Dawley rats were divided into experimental (n = 12 left sciatic nerve injury) and control (n = 6) groups. After six weeks, motor function was evaluated. Muscle and TLF samples were analysed for HA and collagen distribution and concentrations. SFI and gait analysis confirmed a functional deficit in PNI rats 6 weeks after surgery. HA concentration in both sides of the muscles decreased by approximately one-third; both sides showed significantly higher collagen concentration than healthy rats (12.74 ± 4.83 µg/g), with the left (32.92 ± 11.34 µg/g) significantly higher than the right (20.15 ± 7.03 µg/g). PNI rats also showed significantly lower HA (left: 66.95 ± 20.08 µg/g; right: 112.66 ± 30.53 µg/g) and higher collagen (left: 115.89 ± 28.18 µg/g; right: 90.43 ± 20.83 µg/g) concentrations in both TLF samples compared to healthy rats (HA: 167.18 ± 31.13 µg/g; collagen: 47.51 ± 7.82 µg/g), with the left TLF more affected. Unilateral lower limb PNI induced HA reduction and collagen accumulation in both the lower limb muscles and the TLF, potentially exacerbating motor function impairment and increasing the risk of low back dysfunctions.

Sonographic measurement of deep fascia parameters - Interrater reliability

PURPOSE

The deep fascia has recently been a current topic in many medical fields, including rehabilitation. Some research has already focused on assessing deep fascia, however results of individual authors differ in certain aspects. This study focuses on the inter-rater reliability of ultrasound (US) measurement of the thickness of deep fascia and loose connective tissue (LCT). The aim was to define the causes of any discrepancies in measurement that could contribute to the unification of management of evaluating fascia.

METHODS

An observational study was performed including 20 healthy individuals in whom fascia lata of the anterior thigh was examined by US imaging and then measured in Image J software. Three raters participated in this study: the first with 6 years of US imaging experience, other two were newly trained. The measurement of fascial parameters was conducted in two phases with special consultation between them resulting in an agreement of the research team on the more precise way of measurement.

RESULTS

Results revealed the value of inter-rater reliability ICC3,1 = 0.454 for deep fascia thickness and ICC3,1 = 0.265 for LCT thickness in the first phase and any significant difference in the second phase. This poor inter-rater reliability led to a search for possible causes of discrepancies, which authors subsequently highlighted.

CONCLUSION

The findings of the study show the main pitfalls of deep fascia measurement that should contribute to the unification of evaluation.

Understanding frictional behavior in fascia tissues through tribological modeling and material substitution

The objective of this study is to develop a reliable tribological model to enable a more thorough investigation of the frictional behavior of fascia tissues connected to non-specific lower back pain. Several models were designed and evaluated based on their coefficient of friction, using a low-frequency, low-load reciprocating motion. The study found that two technical elastomers, layered on PDMS to simulate the fascia and underlying muscle, are suitable substitutes for biological tissue in the model. The influence of tribopair geometry was also examined, and the results showed that greater conformity of contact leads to a lower COF, regardless of the material combination used. Finally, the friction properties of HA of various molecular weights and concentrations were tested.

Extracorporeal ShockWave Treatment vs. mesotherapy in the treatment of myofascial syndromes: a clinical trial

Numerous scientific papers have compared different treatment options in the management of myofascial pain syndrome. This study evaluated the efficacy of Extracorporeal ShockWave Treatment (ESWT) and mesotherapy in patients with Myofascial Pain Syndrome (MPS) in terms of improvement in pain, functional capacity, and quality of life. A case-control study was conducted on 54 patients, who were randomized into 2 groups: group A, consisting of 27 patients, who were treated with 5 sessions of focal ESWT on a weekly basis; and group B, consisting of 27 patients, who underwent 5 sessions of mesotherapy with Thiocolchicoside fl 4 mg/2 mL and Mepivacaine fl 10 mg/1 mL on a weekly basis. Patients were evaluated at enrollment (T0), after 5 weeks, at the end of rehabilitation treatment (T1), and at a follow- up 30 days after the end of treatment (T2), by administering rating scales (Numeric Rating Scale (NRS) - Pressure Pain Threshold (PPT) - Short Form-36 (SF-36)). The results showed that focal ESWT and Mesoterapy are two valid and effective treatment options in reducing algic symptoms and improving short- and long-term quality of life. However, the use of ESWTs, despite being mildly painful but tolerated, has been shown to be superior to mesotherapy in terms of pain reduction and increased functional capacity.

Do the fasciae of the soleus have a role in plantar fasciitis?

Plantar fasciitis is a chronic, self-limiting, and painful disabling condition affecting the inferomedial aspect of the heel, usually extending toward the metatarsophalangeal joints. There is compelling evidence for a strong correlation between Achilles tendon (AT) loading and plantar aponeurosis (PA) tension. In line with this, tightness of the AT is found in almost 80% of patients affected by plantar fasciitis. A positive correlation has also been reported between gastrocnemius-soleus tightness and heel pain severity in this condition. Despite its high prevalence, the exact etiology and pathological mechanisms underlying plantar heel pain remain unclear. Therefore, the aim of the present paper is to discuss the anatomical and biomechanical substrates of plantar fasciitis with special emphasis on the emerging, though largely neglected, fascial system. In particular, the relationship between the fascia, triceps surae muscle, AT, and PA will be analyzed. We then proceed to discuss how structural and biomechanical alterations of the muscle-tendon-fascia complex due to muscle overuse or injury can create the conditions for the onset of PA pathology. A deeper knowledge of the possible molecular mechanisms underpinning changes in the mechanical properties of the fascial system in response to altered loading and/or muscle contraction could help healthcare professionals and clinicians refine nonoperative treatment strategies and rehabilitation protocols for plantar fasciitis.

The difference in the upper trapezius deep fascia slides between individuals with and without myofascial pain syndrome: A case-control study

INTRODUCTION

MPS is a chronic disorder caused by myofascial trigger points, leading to pain and limited neck movements due to impacted fascia. Studies have reported reduced fascia slides in chronic low back pain, but limited fascia slides in MPS patients are still unreported.

AIM

We determined differences in upper trapezius' deep fascia slides between MPS and non-MPS participants.

METHODS

Between January-August 2019, participants from diverse work sectors were recruited in Manila. An expert physiotherapist diagnosed MPS, while non-MPS participants performed full painless cervical movements. Participants underwent upper trapezius deep fascia scans on both shoulders while performing six cervical movements. An HS1 Konica Minolta ultrasound recorded the data. Two blinded physiotherapists used Tracker 5.0 © 2018 to analyze videos and quantify deep fascia slides by measuring the distance between two x-axis points. The Multivariate analysis of variance (MANOVA) assessed deep fascia slide differences in six active cervical movements. Pillai's Trace, with a range of 0-1 and a p-value of <0.05, was set. Effect sizes in individuals with and without MPS were calculated using Hedges' g and Cohen's d.

RESULTS

Of the 327 participants (136 non-MPS, 191 MPS), 101 MPS participants had shoulder pain for <1 year and 103 experienced unilateral pain. The study examined 3800 ultrasound videos but found no significant difference in deep fascia slides across cervical movements between MPS and non-MPS groups (Pillai's Trace = 0.004, p = 0.94). Minor differences in deep fascia displacement were observed, with small effect sizes (g = 0.02-0.08).

CONCLUSION

A limited deep fascia slide does not characterize MPS participants from non-MPS participants.

Injecting hyaluronan in the thoracolumbar fascia: A model study

Hyaluronan (HA) has been recently identified as a key component of the densification of thoracolumbar fascia (TLF), a potential contributor to non-specific lower back pain (LBP) currently treated with manual therapy and systemic or local delivery of anti-inflammatory drugs. The aim of this study was to establish a novel animal model suitable for studying ultrasound-guided intrafascial injection prepared from HA with low and high Mw. Effects of these preparations on the profibrotic switch and mechanical properties of TLF were measured by qPCR and rheology, respectively, while their lubricating properties were evaluated by tribology. Rabbit proved to be a suitable model of TLF physiology due to its manageable size enabling both TLF extraction and in situ intrafascial injection. Surprisingly, the tribology showed that low Mw HA was a better lubricant than the high Mw HA. It was also better suited for intrafascial injection due to its lower injection force and ability to freely spread between TLF layers. No profibrotic effects of either HA preparation in the TLF were observed. The intrafascial application of HA with lower MW into the TLF appears to be a promising way how to increase the gliding of the fascial layers and target the myofascial LBP.

A model for personalized diagnostics for non-specific low back pain: the role of the myofascial unit

Low back pain (LBP) is the leading cause of disability worldwide. Most LBP is non-specific or idiopathic, which is defined as symptoms of unknown origin without a clear specific cause or pathology. Current guidelines for clinical evaluation are based on ruling out underlying serious medical conditions, but not on addressing underlying potential contributors to pain. Although efforts have been made to identify subgroups within this population based on response to treatment, a comprehensive framework to guide assessment is still lacking. In this paper, we propose a model for a personalized mechanism-based assessment based on the available evidence that seeks to identify the underlying pathologies that may initiate and perpetuate central sensitization associated with chronic non-specific low back pain (nsLBP). We propose that central sensitization can have downstream effects on the "myofascial unit", defined as an integrated anatomical and functional structure that includes muscle fibers, fascia (including endomysium, perimysium and epimysium) and its associated innervations (free nerve endings, muscle spindles), lymphatics, and blood vessels. The tissue-level abnormalities can be perpetuated through a vicious cycle of neurogenic inflammation, impaired fascial gliding, and interstitial inflammatory stasis that manifest as the clinical findings for nsLBP. We postulate that our proposed model offers biological plausibility for the complex spectrum of clinical findings, including tissue-level abnormalities, biomechanical dysfunction and postural asymmetry, ecological and psychosocial factors, associated with nsLBP. The model suggests a multi-domain evaluation that is personalized, feasible and helps rule out specific causes for back pain guiding clinically relevant management. It may also provide a roadmap for future research to elucidate mechanisms underlying this ubiquitous and complex problem.

Concurrent validity of palpation and musculoskeletal ultrasound in evaluating the fascia of individuals with and without myofascial pain syndrome

BACKGROUND AND PURPOSE

Palpation evaluates the fascia, a three-dimensional web of connective tissues. We propose altered fascia system displacement in patients with myofascial pain syndrome. This study determined the concurrent validity of palpation and musculoskeletal ultrasound (MSUS) videos played on Windows Media Player 10 (WMP) when evaluating the direction of the fascia system's displacement at the end of the cervical active range of motion (AROM).

METHODS

This cross-sectional study used palpation as index test and MSUS videos on WMP as reference test. First, three physical therapists palpated right and left shoulders for each cervical AROM. Second, during cervical AROM, PT-Sonographer recorded the fascia system displacement. Third, using the WMP, the physical therapists evaluated the direction of skin, superficial and deep fascia displacements at the end of cervical AROM. MedCalc Version 19.5.3 determined the "exact" Clopper-Pearson Interval (CPI).

RESULTS

We found strong accuracy between palpation and MSUS videos on WMP when determining the direction of skin displacement during cervical flexion and extension (CPI= 78.56 to 96.89). There was moderate agreement between palpation and MSUS videos on WMP when determining the direction of the skin, superficial fascia, and deep fascia displacements during cervical lateral flexion and rotation (CPI= 42.25 to 64.13).

CONCLUSION

Skin palpation during cervical flexion and extension may be useful in evaluating patients with myofascial pain syndrome (MPS). It is unclear what fascia system was evaluated when shoulders were palpated at the end of cervical lateral flexion and rotation. Palpation as diagnostic tool for MPS was not investigated.

Free-aldehyde neutralized and oligohyaluronan loaded bovine pericardium with improved anti-calcification and endothelialization for bioprosthetic heart valves

The number of patients with valvular heart disease is increasing yearly, and valve replacement is the most effective treatment, during which bioprosthetic heart valves (BHVs) are the most widely used. Commercial BHVs are mainly prepared with glutaraldehyde (Glut) cross-linked bovine pericardial or porcine aortic valves, but the residual free aldehyde groups in these tissues can cause calcification and cytotoxicity. Moreover, insufficient glycosaminoglycans (GAGs) in tissues can further reduce biocompatibility and durability. However, the anti-calcification performance and biocompatibility might be improved by blocking the free aldehyde groups and increasing the GAGs content in Glut-crosslinked tissues. In our study, adipic dihydrazide (ADH) was used to neutralize the residual free aldehyde groups in tissues and provide sites to blind with oligohyaluronan (OHA) to increase the content of GAGs in tissues. The modified bovine pericardium was evaluated for its content of residual aldehyde groups, the amount of OHA loaded, physical/chemical characteristics, biomechanical properties, biocompatibility, and in vivo anticalcification assay and endothelialization effects in juvenile Sprague-Dawley rats. The results showed that ADH could completely neutralize the free aldehyde groups in the Glut-crosslinked bovine pericardium, the amount of OHA loaded increased and the cytotoxicity was reduced. Moreover, the in vivo results also showed that the level of calcification and inflammatory response in the modified pericardial tissue was significantly reduced in a rat subcutaneous implantation model, and the results from the rat abdominal aorta vascular patch repair model further demonstrated the improved capability of the modified pericardial tissues for endothelialization. Furthermore, more α-SMA+ smooth muscle cells and fewer CD68+ macrophages infiltrated in the neointima of the modified pericardial patch. In summary, blocking free-aldehydes and loading OHA improved the anti-calcification, anti-inflammation and endothelialization properties of Glut-crosslinked BHVs and in particularly, this modified strategy may be a promising candidate for the next-generation of BHVs.

Hyaluronan homeostasis and its role in pain and muscle stiffness

Hyaluronan (HA) is a glycosaminoglycan that consists of single-chain polymers of disaccharide units of glucuronic acid and N-acetylglucosamine. It is a chief constituent of the extracellular matrix. About 27% of the total HA in the body is expressed in the skeleton and connective tissue, while 8% is expressed in muscles. In physiological conditions, HA functions as a lubricant and viscoelastic shock absorber. Additionally, HA is part of complex cellular signaling which modulates nociception and inflammation. This study aims to understand the role that HA plays in the musculoskeletal system, specifically in muscles and the surrounding fascia. This review is also intended to further understand HA homeostasis and the process of its synthesis, degradation, and clearance from the local tissue. The authors examined muscle pain and stiffness as pathological conditions associated with HA accumulation.

Hyaluronic acid-rich burger separator edible disc prepared from slaughterhouse waste

In this study, the edible films from chicken feet (CF), ovine muscle fascia (MF), and bovine bone gelatin (Gel) were prepared and their characteristics were analyzed, and we also evaluated the sensory quality of raw and cooked hamburgers using the edible films. The quantities of the CF and MF hyaluronic acid were evaluated using colorimetry and spectrophotometry. The CF, MF, and Gel films were prepared by solvent casting method. Results indicated that the concentration of hyaluronic acid in CF (124.11 ppm) was greater than MF (101.11 ppm). The antioxidative property of the CF film (18.47%) was greater than the Gel (1.88%) and MF (Undetectable) film. The CF film was more resistant to water vapor permeability (2.75 × 10-9 g/m.s.pa) than the MF (1.57 × 10-8 g/m.s.pa) and Gel (1.5 × 10-7 g/m.s.pa) films. The Gel film had more appropriate mechanical properties than CF and MF films. The films kept burgers patties independent from one another and prevented them from sticking and freezing together. MF and CF films were able to promote the organoleptic properties of raw and cooked hamburgers in taste and texture.

Edible hyaluronic acid-rich burger separator discs prepared from slaughterhouse waste

In this study, edible films from chicken feet extract (CF), ovine muscle fascia extract (MF), and bovine bone gelatin powder (Gel) were prepared and their characteristics were analyzed. We also used the films as separators of burger cuts and evaluated the organoleptic characteristics of cooked burgers. Hyaluronic acid quantities of CF and MF were measured using colorimetric and spectrophotometry. Results indicated that the concentration of hyaluronic acid in CF (124.11 ppm) was greater than MF (101.11 ppm). The antioxidative property of the CF film (18.47%) was greater than the Gel (1.88%) and MF (Undetectable) films. The CF film was more resistant to water vapor permeability (2.75 × 10-9 g/m.s.pa) than the MF (1.57 × 10-8 g/m.s.pa) and Gel (1.5 × 10-7 g/m.s.pa) films. The Gel film had more appropriate mechanical properties than CF and MF films. The films kept burgers patties independent from one another and prevented them from sticking and freezing together. MF and CF films were able to promote the organoleptic properties of cooked burgers in taste and texture.

Pilot study assessing the effect of Fascial Manipulation on fascial densifications and associated pain

We assessed effectiveness of Fascial Manipulation (FM) in reducing densification thickness and associated acute pain in normal humans. Fascial densifications were identified using palpation and measured with diagnostic ultrasound within self-reported painful somatic regions. Pain intensity ratings were obtained in response to deep palpation of the self-reported painful somatic region before and after a brief FM intervention. Brief FM resulted in reduced densification thickness as well pain intensity. Sex differences were found neither in densification thickness nor pain intensity at any time point. However, a statistically significant positive correlation between densification thickness and pain intensity was observed in females but not males at both pre-FM and post-FM time points. As such, FM may be an effective therapeutic approach for acute pain associated with fascial densifications. While males and females exhibited comparable densification thickness and pain intensity levels at both pre-FM and post-FM time points, only females showed a statistically significant relationship between pain and densification, suggesting that females may be better able to perceive subtle differences in the magnitude of noxious sensory input.

Distinct displacement of the superficial and deep fascial layers of the iliotibial band during a weight shift task in runners: An exploratory study

Motion of the fascial layers of the iliotibial band (ITB), as a reinforcement of the deep fascia lata, is likely to be relevant for its function and mechanical behaviour. This exploratory study aimed to evaluate the ITB fascial layers displacement during a weight shift task. Thirteen pain-free runners performed a 6-second standing weight shift task. B-mode ultrasound imaging using an automated fascicle tracking algorithm was used to measure proximal and distal displacement of superficial and deep ITB layers at the middle region. To study the potential contributors to individual variation of fascial motion, we recorded the activity of five hip/thigh muscles with electromyography (EMG), thigh/pelvis/trunk position with accelerometers, and centre of pressure with a force plate. Linear regressions estimated the relationship between displacement of fascial layers and hip/trunk angles. Independent t-tests or Fisher's exact tests compared EMG and movement-related parameters between participants who demonstrated motion of the fascia in the proximal and distal directions. Thickness of the ITB and the loose connective tissue between its layers were calculated. Proximal displacement was observed in six (-4.1 ± 1.9 mm [superficial]) and two (-6.2 ± 2.0 mm [deep]) participants. Distal displacement was observed for seven participants for each layer (3.1 ± 1.1 mm [superficial]; 3.6 ± 1.3 mm [deep]). Four participants did not show displacement of the deep layer. Trunk lateral flexion and gluteus medius muscle activity were determinants of proximal motion of the superficial layer. Loose connective tissue was thinner in participants without displacement of the deep layer. Displacement of the ITB fascial layers varies between individuals. Variation related to differences in joint movements and muscle activity. This study highlights the complex interaction between fascia and movement.

Fascia Lata Alterations in Hip Osteoarthritis: An Observational Cross-Sectional Study

The present study compares the structure and composition of fascia lata in healthy subjects and in patients with hip osteoarthritis (OA), to evaluate any differences in the amount of Collagen type I, Collagen type III, and Hyaluronan. Fascia lata samples from voluntary healthy subjects and patients with OA were harvested during surgery. Collagen type I (COL I), III (COL III) antibody, and biotinylated hyaluronan binding protein (HABP) immunohistochemistry stainings were used to evaluate fascial morphology and COL I, COL III, and Hyaluronan (HA) content in both groups. Ten samples from healthy subjects and 11 samples from OA patients were collected. COL I was significantly more abundant in the OA group (p = 0.0015), with a median percentage positivity of 75.2 (IQR 13.11)%, while representing only 67 (IQR: 8.71)% in control cases. COL III, with median values of 9.5 (IQR 3.63)% (OA group) and 17.10 (IQR 11)% (control cases), respectively, showed significant reduction in OA patients (p = 0.002). HA showed a median value of 10.01 (IQR 8.11)% in OA patients, denoting significant decrease (p < 0.0001) with respect to the control group median 39.31 (IQR 5.62)%. The observed differences suggest a relationship between fascial pathology and hip OA. The observed increase in COL I in OA patients, along with the reduction of COL III and HA, could lead to fascial stiffening, which could alter fascial mechanics and be linked to the development and symptoms of OA.

Intramuscular hyaluronic acid expression following repetitive power training induced nonfunctional overreaching

Hyaluronic acid (HA) contributes to extracellular matrix viscosity and fiber regeneration. HA role in resistance training (RT) performance adaptations is unclear. RT men performed power training (nonfunctional overreaching (NFOR) or normal training (CG)) over 7.5 days. Post RT, the CG improved power while NFOR did not with HA content decreasing 34.5% in NFOR with no change in CG. HA is critical for muscular recovery; decreased HA may contribute to impaired power adaptations with NFOR RT. Novelty: Nonfunctional over-reaching decreases muscular hyaluronic acid.

Furnishing Wound Repair by the Subcutaneous Fascia

Mammals rapidly heal wounds through fibrous connective tissue build up and tissue contraction. Recent findings from mouse attribute wound healing to physical mobilization of a fibroelastic connective tissue layer that resides beneath the skin, termed subcutaneous fascia or superficial fascia, into sites of injury. Fascial mobilization assembles diverse cell types and matrix components needed for rapid wound repair. These observations suggest that the factors directly affecting fascial mobility are responsible for chronic skin wounds and excessive skin scarring. In this review, we discuss the link between the fascia's unique tissue anatomy, composition, biomechanical, and rheologic properties to its ability to mobilize its tissue assemblage. Fascia is thus at the forefront of tissue pathology and a better understanding of how it is mobilized may crystallize our view of wound healing alterations during aging, diabetes, and fibrous disease and create novel therapeutic strategies for wound repair.

Diabetic Foot: The Role of Fasciae, a Narrative Review

Simple Summary

Diabetes mellitus and its complications are increasingly prevalent worldwide with severe impacts on patients and health care systems. Diabetic foot ulcers have an important impact on disability, morbidity, and mortality. The mechanism of diabetic wound chronicity has not yet been understood in a complete way. Regarding the involved soft tissues, little space has been given to the fasciae, even if nowadays there is more and more evidence of their role in proprioception, muscular force transmission, skin vascularization and tropism, and wound healing. Thus, we aimed to deepen the fascial involvement in diabetic wounds. Based on this review, we suggest that a clear scientific perception of fascial role can improve treatment strategies and create new perspectives of treatment.

Abstract

Wound healing is an intricate, dynamic process, in which various elements such as hyperglycemia, neuropathy, blood supply, matrix turnover, wound contraction, and the microbiome all have a role in this “out of tune” diabetic complex symphony, particularly noticeable in the complications of diabetic foot. Recently it was demonstrated that the fasciae have a crucial role in proprioception, muscular force transmission, skin vascularization and tropism, and wound healing. Indeed, the fasciae are a dynamic multifaceted meshwork of connective tissue comprised of diverse cells settled down in the extracellular matrix and nervous fibers; each constituent plays a particular role in the fasciae adapting in various ways to the diverse stimuli. This review intends to deepen the discussion on the possible fascial role in diabetic wounds. In diabetes, the thickening of collagen, the fragmentation of elastic fibers, and the changes in glycosaminoglycans, in particular hyaluronan, leads to changes in the stiffness, gliding, and the distribution of force transmission in the fasciae, with cascading repercussions at the cellular and molecular levels, consequently feeding a vicious pathophysiological circle. A clear scientific perception of fascial role from microscopic and macroscopic points of view can facilitate the identification of appropriate treatment strategies for wounds in diabetes and create new perspectives of treatment.

Hyaluronan and the Fascial Frontier

The buzz about hyaluronan (HA) is real. Whether found in face cream to increase water volume loss and viscoelasticity or injected into the knee to restore the properties of synovial fluid, the impact of HA can be recognized in many disciplines from dermatology to orthopedics. HA is the most abundant polysaccharide of the extracellular matrix of connective tissues. HA can impact cell behavior in specific ways by binding cellular HA receptors, which can influence signals that facilitate cell survival, proliferation, adhesion, as well as migration. Characteristics of HA, such as its abundance in a variety of tissues and its responsiveness to chemical, mechanical and hormonal modifications, has made HA an attractive molecule for a wide range of applications. Despite being discovered over 80 years ago, its properties within the world of fascia have only recently received attention. Our fascial system penetrates and envelopes all organs, muscles, bones and nerve fibers, providing the body with a functional structure and an environment that enables all bodily systems to operate in an integrated manner. Recognized interactions between cells and their HA-rich extracellular microenvironment support the importance of studying the relationship between HA and the body’s fascial system. From fasciacytes to chronic pain, this review aims to highlight the connections between HA and fascial health.

A Closer Look at the Cellular and Molecular Components of the Deep/Muscular Fasciae

The fascia can be defined as a dynamic highly complex connective tissue network composed of different types of cells embedded in the extracellular matrix and nervous fibers: each component plays a specific role in the fascial system changing and responding to stimuli in different ways. This review intends to discuss the various components of the fascia and their specific roles; this will be carried out in the effort to shed light on the mechanisms by which they affect the entire network and all body systems. A clear understanding of fascial anatomy from a microscopic viewpoint can further elucidate its physiological and pathological characteristics and facilitate the identification of appropriate treatment strategies.

Fascial or Muscle Stretching? A Narrative Review

Stretching exercises are integral part of the rehabilitation and sport. Despite this, the mechanism behind its proposed effect remains ambiguous. It is assumed that flexibility increases, e.g., action on muscle and tendon, respectively, but this is not always present in the stretching protocol of the exercises used. Recently, the fasciae have increased popularity and seems that they can have a role to define the flexibility and the perception of the limitation of the maximal range of motion (ROM). Deep fascia is also considered a key element to transmit load in parallel bypassing the joints, transmitting around 30% of the force generated during a muscular contraction. So, it seems impossible dividing the action of the muscles from the fasciae, but they have to be considered as a “myofascial unit”. The purpose of this manuscript is to evaluate the mechanical behavior of muscles, tendons, and fasciae to better understand how they can interact during passive stretching. Stress-strain values of muscle, tendon and fascia demonstrate that during passive stretching, the fascia is the first tissue that limit the elongation, suggesting that fascial tissue is probably the major target of static stretching. A better understanding of myofascial force transmission, and the study of the biomechanical behavior of fasciae, with also the thixotropic effect, can help to design a correct plan of stretching.

Myofascial Injection Using Fascial Layer-Specific Hydromanipulation Technique (FLuSH) and the Delineation of Multifactorial Myofascial Pain

Background and objectives: The aims of this study were to delineate the contribution of specific fascial layers of the myofascial unit to myofascial pain and introduce the use of ultrasound-guided fascial layer-specific hydromanipulation (FLuSH) as a novel technique in the treatment of myofascial pain. Materials and Methods: The clinical data of 20 consecutive adult patients who underwent myofascial injections using FLuSH technique for the treatment of myofascial pain were reviewed. The FLuSH technique involved measuring the pain pressure threshold using an analog algometer initially and after each ultrasound guided injection of normal saline into the specific layers of the myofascial unit (superficial fascia, deep fascia, or muscle) in myofascial points corresponding with Centers of Coordination/Fusion (Fascial Manipulation^®). The outcome measured was the change in pain pressure threshold after injection of each specific fascial layer. Results: Deep fascia was involved in 73%, superficial fascia in 55%, and muscle in 43% of points. A non-response to treatment of all three layers occurred in 10% of all injected points. The most common combinations of fascial layer involvement were deep fascia alone in 23%, deep fascia and superficial fascia in 22%, and deep fascia and muscle in 18% of injected points. Each individual had on average of 3.0 ± 1.2 different combinations of fascial layers contributing to myofascial pain. Conclusions: The data support the hypothesis that multiple fascial layers are responsible for myofascial pain. In particular, for a given patient, pain may develop from discrete combinations of fascial layers unique to each myofascial point. Non-response to treatment of the myofascial unit may represent a centralized pain process. Adequate treatment of myofascial pain may require treatment of each point as a distinct pathologic entity rather than uniformly in a given patient or across patients.

Cervical Fibrosis as a Predictor of Dysphagia

OBJECTIVE

Radiotherapy of head and neck cancer (HNCA) causes dysfunction through radiation-induced fibrosis (RIF). We hypothesize that the degree of cervical fibrosis is associated with swallowing dysfunction. This study evaluated the association between cervical fibrosis and swallowing dysfunction in patients after radiation therapy for HNCA.

STUDY DESIGN

Cross sectional study.

METHODOLOGY

A convenience sample of patients with dysphagia who were at least 1 year post radiation therapy for HNCA underwent simultaneous cervical ultrasound (US) and video-fluroscopic swallow study (VFSS). US determinants of fibrosis were measurements of sternocleidomastoid fascia (SCMF) thickness bilaterally at the level of the cricoid. Primary and secondary outcome variables on VFSS were pharyngeal constriction ratio, a validated measure of pharyngeal contractility, and penetration aspiration scale (PAS). A qualitative assessment of lateral neck rotation was performed as a functional measure of neck fibrosis.

RESULTS

Simultaneous cervical US and VFSS examinations were performed on 18 patients with a history of radiotherapy for HNCA and on eight controls. The mean (±SD) age of the entire cohort (N = 26) was 66 (±10) years. Individuals with a history of radiation had significantly thinner mean SCMF (0.26 [±0.04 mm]) compared to controls (0.48 [±0.06 mm]; P < .05). Individuals with thinner SCMF were more likely to have moderate to severe restriction in lateral neck rotation, a higher PCR, and a higher PAS (P < .05).

CONCLUSION

Thinner sternocleidomastoid fascia on ultrasound in patients having undergone radiotherapy for head and neck cancer was associated with reduced lateral neck movement, poorer pharyngeal constriction and greater penetration/aspiration scale. The data suggest that cervical fibrosis is associated with swallowing dysfunction in head and neck cancer survivors and support the notion that, "As the neck goes, so does the swallow."

LEVEL OF EVIDENCE

3. Laryngoscope, 131:548-552, 2021.

The Five Diaphragms in Osteopathic Manipulative Medicine: Neurological Relationships, Part 2

The main objective of the osteopath and that of osteopathic manipulative medicine (OMM) is to create space between the different tissues. The sliding capacity of the various tissue layers and between the different body components, up to the possibility of movement between cells is the salutogenic stimulus to allow the circulation of fluids, the biochemical exchange, and the adequate management of the multiple internal and external stimuli that perturb the body living. Movement is allowed by space and space is life. In this second part, the exposure of the anatomical neurological relationships of the five diaphragms continues, highlighting the relationships of the thoracic outlet, the respiratory diaphragm, and the pelvic floor. Finally, there will be clinical reflections to further corroborate the existence of the anatomical continuum and to lay the scientific foundations for an OMM approach to body diaphragms.

Expansion of 1 mL of Solution by Ultrasound-Guided Injection Between the Trapezius and Rhomboid Muscles: A Cadaver Study

OBJECTIVE

An ultrasound-guided interfascial injection, which targets the space between the epimysia, is often performed for myofascial neck and shoulder pain. However, the relationship between the injection volume and clinical effectiveness has been controversial. We conducted an anatomical study with cadavers to measure the distribution of a small amount of pigment solution injected into the interfascial space.

DESIGN

An experimental cadaveric study.

SETTING

An institutional clinical anatomy laboratory.

METHODS

We performed 20 ultrasound-guided injections with pigment solutions of 1.0 mL each into the space between the trapezius muscle and rhomboid muscle bilaterally on 10 cadaver specimens. Cadavers were then dissected and macroscopically evaluated for pigment distribution on the fascia of the muscular surfaces. The pigment distribution area of each injection site was visually confirmed and calculated using automatic area calculation software.

RESULTS

Pigment solution exclusively within the interfascial space was visually confirmed in 95% (19/20) of injection sites. The median pigmented surface area (interquartile range) was 24.50 (16.17-30.76) cm2 on the deep side of the trapezius muscle and 18.82 (13.04-24.79) cm2 on the superficial side of rhomboid muscle; these measurements were statistically significantly different (P = 0.033).

CONCLUSIONS

A pigment solution comprising as little as 1.0 mL injected under ultrasound guidance separated two adjacent muscles and spread to the wide area within the interfascial space. The difference in the pigment distribution area between the two adjacent muscles can be explained by the path made by the injection needle and several layers of fascia between the epimysium.

Early stages of development of the alar fascia (human specimens at 6-12 weeks of development)

In recent years, there has been much discussion concerning the cervical fasciae. The aim of this study is to confirm and to describe the development of the alar fascia as well as its relationship with nearby structures. Histological preparations of 25 human embryos (6-8 weeks of development) and 25 human fetuses (9-12 weeks of development) were studied bilaterally using a conventional optical microscope. Our study confirms the existence of the alar fascia and permits three stages to be established during its development. The initial stage (1st), corresponding to the 6th week of development (Carnegie stages 18-19), is characterized by the beginning of the alar fascia primordium in the retroesophageal space at the level of C7-T1. In the formation stage (2nd), corresponding to the 7th and 8th weeks of development (Carnegie stages 20-23), the alar fascia primordium grows upwards and reaches the level of C2-C3. In the maturation stage (3rd), beginning in the 9th week of development, the visceral, alar and prevertebral fasciae can be identified. The alar fascia divides the retrovisceral space (retropharyngeal and retroesophageal) into two spaces: one anterior (between the alar fascia and the visceral fascia and extending from C1 to T1, named retropharyngeal or retroesophageal space according to the level) and the other posterior (between the alar fascia and the prevertebral fascia, named danger space). We suggest that this latter space be named the retroalar space. This study suggests that alar fascia development is related to mechanical factors and that the alar fascia permits the sliding of the pharynx and the oesophagus during swallowing.

2019 Ejtm Special on Muscle Fascia

For many years the fasciae have been considered by the anatomists only as a "white envelope for the muscles", that is generally removed in anatomical tables, to recognize muscle nerves and vessels. This is one of the reasons that different descriptions of the fasciae exist. On the other hand, in the last years the fasciae and their properties are becoming of central importance to clinicians practicing in various conventional and alternative therapies. The results from the worldwide research activities constitute a body of significant and important data, but this clinical interest is not supported by in-depth comprehension to how integrate the new knowledge about fasciae with the classical biomechanical models based on muscles, tendons and bones. To close this gap an Ejtm Special on "Muscle Fascia" will be published September 30, 2019, but the typescripts will be added to the Ejtm Early Release list as soon as all authors will approve their Epub papers. Deadline for original articles and reviews is June 1st, 2019, but the Editors hope that authors submit their typescripts much earlier.

Variations in contents of hyaluronan in the peritumoral micro-environment of human chondrosarcoma

A concept consolidated in recent years is that tumor growth depends to a great extent on the micro-environment surrounding the tumor, which has a fundamental role in tumor progression and in determining the effectiveness of therapies. Our analysis focuses on chondrosarcoma, the second primary malignant bone tumor, resistant to both chemotherapeutic and radiation therapy. We quantified hyaluronan, one of the main components of the extracellular matrix, with the aim of comparing its amount in the connective tissue surrounding the tumor with intra-tumoral tissue and healthy fascia of the same anatomic district, viewed as a health control. We demonstrate that hyaluronan increased significantly in the peritumoral stroma compared with the healthy fascia, which showed an average amount according to the physical characteristics of body districts by a mean value of 26.9 μg/g. In the peritumoral stroma, the mean hyaluronan content reached 132.6 μg/g (mean value of 63.2 μg/g). The p-value was less than 0.01, showing a highly significant statistical difference. Surprisingly, no significant differences were detected as a function of age, gender, or tumor grade. The levels of hyaluronan were comparable in peritumoral and tumor tissues, although there were differences depending on the state of necrosis. In addition, data on the expression of hyaluronic acid synthetase showed a decrease of about 50% in peritumoral and tumor tissues, indicating alterations in hyaluronan turnover and synthesis. This work demonstrates a variation in hyaluronan contents around the chondrosarcoma, likely correlated with the aggressiveness and resistance to chemotherapy of this tumors. Statement of Clinical Significance: Deeper knowledge about the composition of the peritumoral stroma, rich in extracellular matrix, will enhance better study and understanding of the metastatic potential of tumors and their prognostic indices. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:503-509, 2019.

2019Spring PaduaMuscleDays: Translational Myology and Mobility Medicine

A half-century tradition of skeletal muscles studies, started with a research on fever, is continuing under the auspices of the Interdepartmental Research Centre of Myology (CIR-Myo), Department of Biomedical Sciences, University of Padova, Italy, the A&C M-C Foundation for Translational Myology, Padova, Italy and the European Journal of Translational Myology (EJTM). This year an EJTM Special will be dedicated to Muscle Fascia, an under looked topic, which merits more attention. Furthermore, this year the 2019SpringPaduaMuscleDays: Translational Myology and Mobility Medicine, an International Conference, was held March 28-30, 2019 in Euganei Hills and Padova (Italy). The abstracts of the 2019SpPMD, that are reported in the Myology News of EJTM 29(1), 2019, are excellent examples of translational research. Their excellent contents are at the level needed for approval by Ethical Committees, International Granting Agencies, and Editors of international journals, thanks to the high scientific profiles of researchers and clinicians who are eager to present their results at the PaduaMuscleDays.