Paravertebral Muscle Mechanical Properties in Patients with Axial Spondyloarthritis

Paravertebral Muscle Mechanical Properties in Patients with Axial Spondyloarthritis (2021)

By Sandra Alcaraz-Clariane, Lourdes Garcia-Luque, Juan Luis Garrido-Castro, I. Concepcion Aranda-Valera, Lourdes Ladehesa-Pineda, Marie Angeles Puche-Larrubia, Cristina Carmona-Perez, Daina Priscilla Rodrigues-de-Souza and Francisco Alburquerque-Sendin. 

Different musculoskeletal disorders are a source of pain in the spinal region; most of them can be divided into mechanical, such as low back pain, or inflammatory origins, as is the case of axial spondyloarthritis. Nevertheless, insufficient information is available about the muscle negative consequences of these conditions. Thus, the objective of this study was to identify whether mechanical muscle properties of cervical and lumbar muscles are different between patients with axial spondyloarthritis, low back pain and healthy controls. Furthermore, we aimed to identify whether mechanical muscle properties were related to socioeconomic and clinic variables in various study groups.

Spinal disorders constitute a significant health problem with a high prevalence rate that has increased in recent years. The annual cost for the management of spinal pain costs 17 billion euros in Germany or 100 billion dollars in the United States. Common symptoms and signs have been identified in subjects with spinal pain, such as a decreased range of motion, impaired spinal motor control, increased disability or decreased quality of life. 

Low back pain is the pathology that most contributes to the years lived with disability. Its estimated prevalence in 2017 was about 577 million people, and more than 90% of the total low back pain cases corresponds to unspecific mechanical low back pain. Important muscle morphological changes have been associated with the presence of low back pain. Among them, the presence of fat infiltration, reduction in muscle size, alteration in fibre distribution, and muscle recruitment strategies have been described, as well as their relationship with the evolution time. Although these muscle alterations are well documented, mainly at the lumbar level, it remains unknown whether the muscle behaviour is similar between different causes of spinal pain; it could even depend on the acute or chronic stages. 

It has been described that muscle alternation may be an underestimated source of spinal pain and that muscle physiology determines optimal spinal performance. Indeed, excessive spinal muscle use or disuse is a well-known source of pain. Although magnetic resonance imaging, computed tomography and ultrasound methods have allowed us to assess the soft tissues in spinal pain patients, more information and resources and necessary to describe other muscle features such as mechanical muscle properties. In recent years, the Myoton Pro has provided reliable data in clinical settings, In fact, the determination of mechanical muscle properties has been successfully applied in assessing healthy subjects and athletes, patients with stroke, scoliosis, Parkinson’s, chronic low back pain and cervical dystonia, among others. In spinal pain research, increases in tone and stiffness and decreases in the elasticity of the lumbar paraspinal muscles have been detected with the MyotonPro. However, no data is available in other regions, such as the cervical spine, which could be of interest in terms of the disease state.

Subjects of both sexes, over 18 years, participated in the study. Two groups of cases were defined. First, the axial spondyloarthritis group was compared to patients diagnosed according to the evaluation criteria of the SpondyloArthrits Internation Society. Second, for the low back pain group, the subjects had less than 12 weeks of pain evolution time and a value of ≥3 on the numerical pain rating scale. The existence of any inflammatory pathology was a specific exclusion criterion for this group. The control group included healthy subjects that did not have spinal pain in the past six months or any neurological or musculoskeletal disorder. There were 40 people per group. 

A manual myoyonometer (Myoton Pro) was used to record the mechanical muscle properties of the lumbar and cervical regions with the patient layin in the prone position with the arms along the body. The probe of the device is positioned perpendicular to the erector spine, 2.5cm from the spinous process of L5 on both other sides. The mechanical impulses exerted by the probe, with a pulse of 15 ms and 0.40 N of mechanical force, allowed us to record the tissue response. The mechanical muscle properties are expressed as follows: muscle tension or tone in resting state, defined by frequency; stiffness, which reflects the ability of the muscle to resist contraction or external force that deforms its initial shape; logarithmic decrement in the amplitude of oscillation, which has no unit, and describes the ability of the issue to restore its shape after deformation, characterized the inverse of the elasticity which is the property of progressive deformation while applying constant stress, which reflects the viscosity of the tissue. 

This study showed that cervical and lumbar mechanical muscle properties are different depending on the type of spinal pain. In fact, except for the decrement, the spinal mechanical muscle properties of SpondyloArthrits patients showed a higher tone and stiffness and a lower relaxation and creep than those with low back pain and healthy controls. Furthermore, all lumbar and cervical mechanical muscle properties, expect decrement, correctly classified patients with SpondyloArthrits and healthy subjects, as well as subjects with SpondyloArthrits and low back pain. 

Each one of the groups showed a different pattern of correlations between mechanical muscle properties and sociodemographic and clinical variables, age being the variable most correlated with mechanical muscle properties of both regions for the three groups. 

In general, there were different patterns of correlations depending on the study group. Therefore, different origins or spinal pain can determine specific associations between mechanical muscle properties and other clinical and sociodemographic variables. Age was the variable correlated with a greater number of mechanical muscle properties, which is directly related to tone, stiffness, and decrement and inversely related to relaxation and creep, independent of the study group. These results agree with previous research at the spinal level, both in SpondyloArthrits and low back pain patients and in other regions, such as the neck, upper and lower limb muscles which demonstrate that the advance of age is related to mechanical muscle properties changes, independent of the clinical state. 

The lumbar and cervical mechanical muscle properties are different depending on the type of spinal pain. The patients with SpondyloArthrits show a higher tone and stiffness and a lower relaxation and creep than those with lower back pain and healthy controls. Furthermore, the spinal mechanical muscle properties, expect for decrement, are able to classify patients with SpondyloArthrits and healthy subjects, but not subjects with low back pain and healthy ones, which increases the interest regarding the assessment of spinal mechanical muscle properties as a possible marker of the muscle state and progression in the clinical context of inflammatory spinal pain. 

The patients with SpondyloArthrits show a specific pattern of correlations between machinal muscle properties and clinical and metrological variables that do not appear in low back pain and healthy subjects. This pattern associates a worse state and progression of SpondyloArthrits to higher tone and stiffness in lumbar and cervical regions.

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This is exactly the research that CT Clinic has based their methodologies on; using the knowledge that muscle stiffness is the source of the pain. This is what led to the creation of COPA therapy. 

COPA therapy is the combination of 4 techniques to identify the pain and cure it. This includes Chiropractic, Osteopath, Physiotherapy and Acupuncture techniques. Together this creates COPA therapy which has resulted in over 20,000 pain-free patients.

CT Clinic, based in West Didsbury, Manchester, is a pain specialist clinic that specialises in complicated cases of pain. Many of the patients are managing their pain with painkillers and have been told their pain is ‘untreatable’. CT Clinic believes no one should be left to live with pain. 

By using COPA therapy, we treat lower back pain, knees pain, shoulder pain, rotate cuff pain, hip pain, ankle injury, sport injury, headache, numbness and tingling sensation, wrist pain, sciatica pain, migraine, weakness in arms, meniscus pain, elbow pain, upper back and neck pain, tension in upper back, shoulder and neck pain.

CT Clinic is conducting its own scientific research to prove the effectiveness of COPA therapy. They believe there is a significant gap in research when it comes to pain, proving COPA therapy’s effectiveness and that muscle stiffness as the source of pain will be a massive step in solving pain. 

Using Myoton Technology, CT Clinic have seen proof of their results. Myoton Technology measures muscle stiffness in patients and can be used to see the improvement with each session. Myoton technology is the only machine in the world that can measure muscle stiffness within one minute and is used by NASA and over 600 universities worldwide. CT Clinic is proud to use this to offer innovative care to patients.

The success of COPA therapy hasn’t been unnoticed, CT Clinic has been praised by patients with a range of conditions which can be seen with the 5-star google reviews and patient testimonials.


Ellen Maynard-Smith
CT Clinic Business Developer