September « 2009 « necksolutions.com Blog

September 29, 2009

Megafibers in trapezius myalgia

Increased proportion of megafibers in chronically painful muscles

From: Pain. 2008 Oct 31;139(3):588-93

Trapezius myalgia – chronic pain from the upper trapezius muscle – is frequent in female employees in monotonous stressful jobs, potentially due to chronic overload of type I muscle fibers. In this study, the authors investigated the intra-individual distribution of trapezius muscle fiber size, and hypothesized that females with myalgia compared with matched healthy controls have a higher percentage of grossly hypertrophied type I fibers with poor capillarization.

Forty-two female office workers with trapezius myalgia and 20 healthy matched controls participated in the study. Standard histochemical methods were used to determine fiber size, fiber type, and capillarization. Type I megafiber were defined as at least twice the size of the median type I fiber size of each individual. The main finding was that trapezius myalgia had a significantly higher proportion of type I megafibers than healthy matched controls, in spite of no significant difference in overall type I fiber size. In trapezius myalgia and healthy matched controls type I megafibers were located in 46% and 11% of the females, respectively. Capillarization of the overall type I fiber pool was not different between healthy matched controls and trapezius myalgia, but was significantly lower in type I megafibers of both groups. The percentage of megafibers was positively related to age and weekly working hours, indicating an effect of long-term exposure. In conclusion, this study shows that trapezius myalgia is associated with a significantly higher percentage of grossly hypertrophied type I muscle fibers with poor capillarization – type I megafibers.

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September 26, 2009

Muscone protects vertebral end plate degeneration

Filed under: Arthritis, Disc Problems, Neck Pain — Administrator @ 5:22 am

Muscone Protects Vertebral End plate Degeneration by Antiinflammatory Property

From: Clin Orthop Relat Res. 2009 Sep 18

Neck pain is one of the most common chronic conditions affecting quality of life and sometimes causing disability in adults. Most chronic neck pain is the result of degeneration of the intervertebral discs in the cervical spine. An intact end plate cartilage is critical for normal disc functions, as the major nutrient supply of the discs is diffused through the end plates. Pathological changes in end plate cartilage are closely related to disc degeneration and thus to cervical spondylopathy. Prevention and reduction of lesions to the vertebral end plate are high research priorities.

IL-1beta may play an important role in intervertebral disc degeneration. This being the case, inhibiting IL-1beta could provide a therapeutic approach for reducing or preventing disc degeneration. Muscone reportedly relieves pain and suppresses inflammation. Therefore, the authors asked whether muscone, a potent antiinflammatory agent, could reduce proinflammatory cytokines in vitro (end-plate cartilage cultures) and end-plate degeneration in vivo (a rat model that induces intervertebral disc degeneration). In vitro, muscone reversed IL-1beta-induced upregulation of IL-1beta, tumor necrosis factor alpha, cyclooxygenase 2, inducible nitric oxide synthase, matrix metalloproteinase 13, aggrecanase 2, and nitric oxide and downregulation of Col2alpha1 and aggrecan. Pretreatment with muscone (6.25, 12.5, 25 mumol/L) inhibited the IL-1beta-induced phosphorylation of extracellular signal-regulated kinases 1/2 and c-Jun N-terminal kinase in a dose-dependent manner. In vivo, muscone inhibited the expression of prostaglandin E2, 6-keto-prostaglandin F1alpha, IL-1beta, and tumor necrosis factor alpha and recovered the structural distortion of the degenerative disc. The findings suggest muscone is a promising agent for treating intervertebral disc degeneration through its antiinflammatory effects.

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September 20, 2009

Functional cervical MRI within the scope of whiplash injuries

Filed under: Neck Pain, Whiplash — Administrator @ 9:55 am

Functional cervical MRI within the scope of whiplash injuries: presentation of a new motion device for the cervical spine

From: Surg Radiol Anat. 2009 Sep 18

Frequently following a whiplash injury of the cervical spine, patients suffer from persistent pain symptoms. The MRI will in some of these cases show changes consistent with disc pathology or spinal stenosis, although in most instances the imaging studies will offer no adequate explanation for the described symptoms. The goal of our research was to develop and test a new MRI compatible device that will allow functional imaging of the cervical spine.

A total of 30 patients with whiplash injuries were evaluated during the first 6 weeks following trauma with the functional MRI. The examination was carried out with a T2-weighted turbo spin-echo sequence utilizing a new apparatus consisting of an inflatable air bag contained in a Plexiglas housing. Thanks to a valve placed outside of the examination room, it was possible to individually regulate the amount of air used to fill the pillow, thereby obtaining a full range of motion between flexion and extension.

In 25 cases no pathology was found during this examination. Two patients presented with scarring of the alar ligaments, indicative of a traumatic lesion. In two other instances the images in reclination revealed a bulging disc, while in one case a widening of the disc space was found as a sign for a rupture of the anterior longitudinal ligament.

This study was able to demonstrate the applicability of the new functional testing device, which permits a standardized, continuous and dynamic evaluation of the cervical spine in a closed MRI.

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September 17, 2009

Sustained mechanical loading and disc diffusion

Filed under: Back Pain, Disc Problems, Posture — Administrator @ 3:53 pm

2009 ISSLS Prize Winner: What Influence Does Sustained Mechanical Load Have on Diffusion in the Human Intervertebral Disc?: An In Vivo Study Using Serial Postcontrast Magnetic Resonance

From: Spine (Phila Pa 1976). 2009 Sep 14

An in vivo study of the effects of mechanical loading on transport of small solutes into normal human lumbar intervertebral discs using serial postcontrast magnetic resonance imaging (MRI) to investigate the influence of a sustained mechanical load on diffusion of small solutes in and out of the normal intervertebral disc.

Diffusion is an important source of disc nutrition and the in vivo effects of load on diffusion in human intervertebral disc remains unknown. Forty normal lumbar discs (on MRI) in 8 healthy volunteers were subjected to serial post contrast (Gadoteridol) 3 Tesla MRI in 2 phases. In phase 1 (control), volunteers were scanned at different time points – precontrast and 1.5, 3, 4.5, 6, and 7.5 hours postcontrast injection. In phase 2, 1 month later, the same volunteers were subjected to sustained supine loading for 4.5 hours. MRI scans were performed precontrast (preload) and postcontrast (postloading) at 1.5, 3, and 4.5 hours. Their spines were then unloaded and recovery scans performed at 6 and 7.5 hours postcontrast. In house software was used to analyze images.

Repeated-measures ANOVA and pairwise comparisons at different time points in the central region of the loaded disc compared to the unloaded discs revealed significantly lower signal intensity ratios indicating reduction in transport rates for the loaded discs. Signal intensity ratioscontinued to rise in loaded disc for 3 hours into recovery phase, whereas unloaded discs at the same time point showed a decrease.

Sustained supine creep loading (50% body weight) for 4.5 hours retards transport of small solutes into the center of human IVD and it required 3 hours of accelerated diffusion in recovery state for loaded disc to catch-up with diffusion in unloaded discs. The study supports the theory that sustained mechanical loading impairs diffusion of nutrients entering the disc and quite possibly accelerates disc degeneration.

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September 15, 2009

Lumbopelvic extensor muscle endurance and age

Filed under: Back Pain, Chronic Pain — Administrator @ 8:58 pm

Comparison between elderly and young males’ lumbopelvic extensor muscle endurance assessed during a clinical isometric back extension test.

From: J Manipulative Physiol Ther. 2009 Sep;32(7):521-6

Low back pain is one of the leading causes of disability, contributing to 40% of all workdays lost in the United States of America. Because of the cost associated with work-related low back pain disabilities, most published studies have focused on the working-aged population. However, back pain and neck pain are also common musculoskeletal disorders affecting, each month, approximately one third of adults older than 70 years. The annual prevalence of chronic low back pain ranges from 44% to 84% in adults older than 65 years. In Canada, chronic low back pain is the third and fourth most important chronic health problem in women and men, respectively, older than 65 years. Women with severe chronic low back pain are 3 to 4 times more likely than other women to have difficulty with light housework tasks and 2 times more likely to encounter problems with mobility tasks, such as climbing stairs, walking, or lifting. In Canada, it is estimated that approximately 25% of the population will be older than 65 years by 2031. Anticipating the growing impact of the ageing population, a better understanding of chronic low back pain’s impact on physical capabilities in elderly people is important.

In working aged adults, chronic low back pain has been associated with increased fatigability of the lumbopelvic extensor muscles, as demonstrated by shorter back endurance test duration. In all back endurance protocols reported in the literature, isometric testing procedures with the trunk positioned in a weight-dependent position, such as the Sorensen test, may be most suitable in clinical settings. Weight dependent position tests of muscle endurance are cost-effective, easy to perform in a clinical context, and require no special equipment. The Sorensen test is conducted with subjects lying prone, the upper body unsupported in a horizontal position relative to the ground, and the lower limbs fixed by straps. This procedure has been found to be a reliable measure of position-holding time and can discriminate between subjects with and without low back pain.

Ageing has been related to changes in the neuromuscular system. Among these changes, loss of muscle force generation capacity, a slower firing rate of motor units, and a reduction in motor unit and muscle fiber number have been observed. Together with the loss of muscle fibers, a selective decrease in fast twitch fibers has been demonstrated with advancing age, leading to alteration of muscle fiber type proportion. This shift in fiber-type proportion appears to contribute to changes in muscle fatigability in healthy elderly individuals.

Very few studies have assessed back muscle endurance in elderly subjects. The current investigation aims to evaluate back extensor muscle fatigability in healthy elderly adults by quantifying endurance time during a clinical isometric back endurance test and the posttest decrease of lumbopelvic extensor maximal force. We hypothesized that elderly subjects will experience greater fatigability of lumbopelvic extensor muscles than young subjects.

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September 12, 2009

gluteus medius weakness low back pain during pregnancy

Filed under: Back Pain, Posture — Administrator @ 10:15 am

Association between gluteus medius weakness and low back pain during pregnancy

From: Iowa Orthop J. 2009;29:97-9

This cross-sectional study examines whether there is an association between gluteus medius weakness in the presence of low back pain in pregnant women at any stage of gestation. Prevalence of low back pain during pregnancy is high, and identifying potential etiologies and targeted interventions is lacking. Thus, identification of an association between specific muscle weakness and pain would have clinical relevance. Initial pilot data suggests that weakness of the gluteus medius is strongly associated with the presence of low back pain during pregnancy.

Low back pain during pregnancy is considered a significant public health issue due to its high prevalence and associated health care costs. Prevalence ranges between 49-68.5% with up to one third of these women having pain that limits their ability to perform basic activities of daily living. Ten percent of women with chronic low back pain link the onset of their pain to pregnancy. Physical therapy literature and physical therapy clinical practice relating to low back pain in pregnancy has historically involved discussion of postural dysfunction, sacroiliac joint dysfunction, and “sciatica.” The authors of this proposal offer another possible correlation explaining back pain during pregnancy relating to gluteus medius performance.

It is the experience of the authors of this proposal that pregnant women routinely present to their physical therapy clinic with “radiculopathy” or “sciatica.” In fact, the incidence of herniated disc in pregnancy is actually quite rare (1%). Often, the physical exam does not reveal any neurologic findings indicative of radiculopathy, but instead reveals weakness and/or strain of the gluteus medius. Gluteus medius strain can present as low back pain either due to facet joint irritation relating to Trendelenburg gait, or can be referred pain from the gluteus medius itself. If a true neurologic weakness were present, one would expect to find both tensor fascia lata and posterior gluteus medius weak as they are commonly innervated (L5). Rather, in the authors experience weakness is specific to the gluteus medius. Foti et al. performed 3-dimensional gait analysis on 15 pregnant women during the second half of their pregnancy and again one year post-partum. Gait analysis includes both kinetic and kinematic parameters. The authors found significant changes in kinetic gait parameters during pregnancy, and offer this as an explanation for how
gait motion overall remains relatively unchanged. They found increased demand on the ankle plantar flexors, hip abductors, and hip extensors. Atrophied tissues, or weak muscles, are less tolerant of physical stresses applied. Pregnant women with weakness of the gluteus medius are therefore vulnerable for tissue injury—both because of the increased magnitude of stress applied (weight gain), and a decrease in stress tolerated before injury/strain.

Thus, the primary aim of this pilot study was to determine the association between weakness of the gluteus medius and the presence of low back pain during pregnancy.

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September 9, 2009

Painful neck rotation for crowned dens syndrome

Filed under: Neck Pain — Administrator @ 2:52 pm

Painful neck on rotation: diagnostic significance for crowned dens syndrome

From: J Neurol. 2009 Aug 30

The crowned dens syndrome is a clinicoradiological entity defined as acute neck pain due to deposition of crystals surrounding the odontoid process. Crystal deposition may occur without symptoms or exhibit myelopathy by compressing the spinal cord. Neck pain on lateral rotation has been described in the previous papers for crowned dens syndrome. We tested the validity of “painful neck on rotation” as a potential diagnostic tool to differentiate crowned dens syndrome from meningeal irritation. Patients 1 and 2 were relatively young females and showed acute cervico-occipital pain, with marked limitation on neck rotation. Patient 2 was suspected to have neck strain, since there was no fever and no elevated CRP. In contrast, patient 3 was an older female and showed headache and limitation of neck rotation. Cerebrospinal fluid was normal in spite of inflammatory reaction on laboratory markers. All three patients showed absence of or only a mild limitation on neck flexion. A computed tomography scan focused on the craniocervical junction revealed mottled calcification around the odontoid process. Painful neck on rotation may have diagnostic implications for crowned dens syndrome in patients with cervico-occipital pain.

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September 4, 2009

Postural responses in healthy seated individuals

Filed under: Neck Pain, Posture — Administrator @ 7:22 pm

A paradigm to assess postural responses triggered by anteroposterior translations in healthy seated individuals

From: Gait Posture. 2009 Aug 31.

Postural adjustments following mechanical perturbations have been studied in healthy seated humans. However, little is known on the minimal intensity that should be used to provoke a reaction. This knowledge could be essential to assess seated postural deficits in some pathological populations. The goal of the present study was to identify a low-intensity perturbation that could elicit postural reactions in healthy seated individuals.

Six healthy participants sat on an adapted ergonomic chair fixed on a moveable support surface that was submitted to forward and backward translations. The head and trunk kinematics as well as the activity of sixteen neck and trunk muscles were recorded. The head, arm and trunk center of mass was computed using kinematics and standard anthropometric tables. The authors found that ramp displacements with an acceleration profile reaching a maximal value of 1.17m/s(2) elicited reliable kinematic and electromyographic reactions across participants. Head and trunk segments initially responded opposite to the direction of translation, then reversed direction. Median peak-to-peak angular displacements in the neck, head and trunk, respectively, reached 3.6 degrees , 7.0 degrees and 7.1 degrees for forward translations, and 4.0 degrees , 8.2 degrees and 7.0 degrees for backward translations.

For forward translations, neck and trunk flexor muscles were activated first, followed by the extensor muscles, whereas for backward translations, extensor muscles were activated first, followed by flexors. Although this perturbation is of low-intensity compared to those typically used previously to evoke postural reactions, this stimulus is sufficient to elicit a reliable response. We suggest that such a perturbation could be used to assess the physical condition of individuals with neck injuries.

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September 1, 2009

Psychological factors in patients with subacute neck pain

Filed under: Neck Pain — Administrator @ 3:09 pm

Are psychological factors prognostic indicators of outcome in patients with subacute neck pain?

From: Man Ther. 2009 Aug 28.

The aim was to determine if psychological factors favourably influence the short and long-term outcome of patients with subacute neck pain in terms of global perceived recovery, pain, using a Numerical Rating Scale and functional disability, using the Neck Disability Index. This study was conducted within the framework of a randomised clinical trial comparing two types of conservative therapy in 146 patients with subacute neck pain. Multilevel techniques were used for data-analysis. The short and long term results for the three outcomes were very diverse. The sub-scales of the used questionnaires, i.e. the Pain Coping and Cognition List, and the 4 Dimensional Symptom Questionnaire, did not contribute significantly to all of the multilevel models. Only the factor ‘fear of movement’ was consistently and significantly present in the univariable analysis for all outcomes at both follow-up measurements. The explained variance in the short term ranged from 16% to 30%, and from 6% to 34% in the long term. This can be considered to be low. The authors conclude that all psychological factors showed a considerable variation on the specific measurement and time point used. Only ‘fear of movement’ consistently impedes short term and long term recovery. Further prognostic research is needed to achieve more consistent results.

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