Human intervertebral disc internal strain in compression: The effect of disc region, loading position, and degeneration
From: J Orthop Res. 2010 Oct 26. [Epub ahead of print]
The primary function of the disc is mechanical; therefore, degenerative changes in disc mechanics and the interactions between the annulus fibrosus and nucleus pulposus in nondegenerate and degenerate discs are important to functional evaluation. The disc experiences complex loading conditions, including mechanical interactions between the pressurized nucleus pulposus and the surrounding fiber-reinforced annulus fibrosus. Our objective was to noninvasively evaluate the internal deformations of nondegenerate and degenerate human discs under axial compression with flexion, neutral, and extension positions using magnetic resonance imaging and image correlation. The side of applied bending (e.g., anterior annulus fibrosus in flexion) had higher tensile radial and compressive axial strains, and the opposite side of bending exhibited tensile axial strains even though the disc was loaded under axial compression. Degenerated discs exhibited higher compressive axial and tensile radial strains, which suggest that load distribution through the disc subcomponents are altered with degeneration, likely due to the depressurized nucleus pulposus placing more of the applied load directly on the annulus fibrosus. The posterior annulus fibrosus exhibited higher compressive axial and higher tensile radial strains than the other annulus fibrosus regions, and the strains were not correlated with degeneration, suggesting this region undergoes high strains throughout life, which may predispose it to failure and tears. In addition to understanding internal disc mechanics, this study provides important new data into the changes in internal strain with degeneration, data for validation of finite element models, and provides a technique and baseline data for evaluating surgical treatments.
Analysis of visually guided eye movements in subjects after whiplash injury
From: Auris Nasus Larynx. 2010 Oct 22. [Epub ahead of print]
The aims of present research were to analyze the visually guided eye movements of subjects suffering from the consequences of whiplash injury and the possibility to differentiate patients from feigning subject. The authors analyzed the role of video-nystagmography for clinical and forensic aspects.
It was a prospective case-control study. Detailed history was taken and patients were thoroughly investigated. Smooth pursuit and saccadic eye movements were assessed in 33 patients affected by imbalance following a whiplash injury. A control group of 20 subjects was also evaluated. All tests were executed in neutral neck position and after left and right trunk rotation.
The t-test, applied to all parameters showed that difference of the parameter between the groups was not statistically significant. The visually guided eye movement evaluation does not seem to offer a clinically relevant method to differentiate patients suffering from the effects of whiplash injury from normal subjects.
A longitudinal study of low back pain and daily vibration exposure in professional drivers
From: Ind Health. 2010;48(5):584-95
Long-term exposure to whole body vibration in professional drivers of machines and/or vehicles used in industry, agriculture/forestry, and public utilities is associated with an excess risk for back symptoms and disorders of the lumbar tract of the spine. Epidemiological studies and reviews have reported a higher occurrence of low back pain, herniated disc and early degeneration of the spine in the exposed drivers than in either worker groups unexposed to whole body vibration or the general population. Driving of vehicles involves not only exposure to harmful whole body vibration but also to several ergonomic risk factors which can affect the spinal system, such as prolonged sitting and awkward postures. Moreover, some driving occupations involve heavy lifting and manual handling activities (e.g. drivers of delivery trucks), which are known to strain the lower part of the back. Individual characteristics (e.g. age, body mass, and smoking) and psychosocial factors are also suggested as potential predictors for low back pain. It follows that injuries in the lower back of professional drivers may be considered a complex of health disorders of multifactorial origin involving both occupational and non-occupational stressors.
The European (EU) Directive on mechanical vibration provides qualitative and quantitative guidance to protect workers against the risks arising from exposure to vibration at work. In the EU Directive, whole body vibration is defined as ‘the mechanical vibration that, when transmitted to the whole body, entails risks to the health and safety of workers, in particular lower back morbidity and trauma of the spine.
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Radiologic evaluation of chronic neck pain
From: Am Fam Physician. 2010 Oct 15;82(8):959-64
Chronic neck pain presents both diagnostic and therapeutic dilemmas because of considerable controversy in the literature over its etiology, as well as the role of imaging in its evaluation. Regarding etiology, the literature focuses on two general categories: post-traumatic and degenerative. Post-traumatic etiologies include the so-called “whiplash” syndrome, defined as any injury to the cervical vertebrae and adjacent soft tissues as a result of sudden jerking. This classically includes extension-flexion mechanisms sustained in rear-end motor vehicle collisions as well as abrupt lateral flexion mechanisms. In addition, research in Canada and Scandinavia has identified a constellation of signs and symptoms termed whiplash associated disorders.
For many years, there were no guidelines for evaluating patients with chronic neck pain. However, in the past 15 years, considerable research has led to recommendations regarding whiplash associated disorders. This article summarizes the American College of Radiology Appropriateness Criteria for chronic neck pain. Imaging plays an important role in evaluating patients with chronic neck pain. Five radiographic views (anteroposterior, lateral, open-mouth, and both oblique views) are recommended for all patients with chronic neck pain with or without a history of trauma. Magnetic resonance imaging should be performed in patients with chronic neurologic signs or symptoms, regardless of radiographic findings. The role of magnetic resonance imaging in evaluating ligamentous and membranous abnormalities in persons with whiplash associated disorders is controversial. If there is a contraindication to magnetic resonance imaging, computed tomography myelography is recommended. Patients with normal radiographic findings and no neurologic signs or symptoms, or patients with radiographic evidence of spondylosis and no neurologic findings, need no further imaging studies.
Revision of the American Association of Dental Research’s Science Information Statement about Temporomandibular Disorders
From: J Can Dent Assoc. 2010 Oct;76:a115
Despite continuing research, which is providing an increasing evidence base, the dental profession still does not have a standard of care for diagnosing or managing temporomandibular disorders. Although guidelines have been published by organizations including the American Academy of Orofacial Pain and the American Academy of Oral Medicine, which has published a handbook for managing various orofacial conditions causing pain, these are not officially recognized as authoritative documents by national associations. The Canadian Dental Association and American Dental Association have not established clinical guidelines for this segment of dental practice. To our knowledge, the only North American dental organization that has published temporomandibular disorder guidelines—in 1999, revised in 2009—is the Royal College of Dental Surgeons of Ontario.
In 1996, the American Association of Dental Research published a science information statement on temporomandibular disorders, based on recommendations submitted by its Neuroscience Group. This document, which was based on evidence at that time, provided guidelines for the diagnosis and management of temporomandibular disorders. In 2010, the statement was revised in light of continuing research and the strengthened evidence base. After a broad literature review by the American Association of Dental Research’s Neuroscience Group and a lengthy process of administrative review and revision, the updated official American Association of Dental Research temporomandibular disorder statement was approved in March 2010.
The American Association of Dental Research recognizes that temporomandibular disorders encompass a group of musculoskeletal and neuromuscular conditions that involve the temporomandibular joints, the masticatory muscles, and all associated tissues. The signs and symptoms associated with these disorders are diverse, and may include difficulties with chewing, speaking, and other orofacial functions. They also are frequently associated with acute or persistent pain, and the patients often suffer from other painful disorders (comorbidities). The chronic forms of temporomandibular disorder pain may lead to absence from or impairment of work or social interactions, resulting in an overall reduction in the quality of life.
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The more the worse: the grade of noise-induced hearing loss associates with the severity of tinnitus
From: Int J Environ Res Public Health. 2010 Aug;7(8):3071-9. Epub 2010 Aug 4.
Tinnitus is a perception of sound without an external source. This perception can be induced by various dysfunctions on several levels of the peripheral or central auditory pathway. Regardless of the original cause, all patients complain of hearing a tinnitus tone on either one (unilateral) or both sides (bilateral) of the head or ears. Depending on the case, tinnitus tone may have low, medium or high frequency and be either relatively quiet (0–3 dB), going up to relatively loud (more than 16 dB). Tinnitus may take acute (up to 3 months), sub-acute (4–12 months) or a chronic turn (longer than a year). Regarding the level of disturbance, tinnitus can be classified as compensated (low-level distress) or decompensated (high-level distress). The major problem in patients with decompensated tinnitus is sleep interference, because the tinnitus tone keeps the patients awake. Other diseases that follow include depression, a variety of phobias, anxiety disorders, problems with concentration and in extreme cases—suicide. In other words, decompensated tinnitus seriously reduces the quality of life. Approximately 30 per 100 adults experience tinnitus, whereas about 1–5 persons per 100 suffer from tinnitus and seek medical help. In the Western world, tinnitus has a big economic impact.
The onset of tinnitus can have various basis such as neurologic, traumatic, infectious or drug-related, however, the major cause of tinnitus is a hearing loss. Hearing loss is usually caused by the aging process (presbycusis) or by the overexposure to noise (noise-induced hearing loss). Occupational noise, together with environmental noise pollution, are two major factors contributing to the noise-induced hearing loss. Newly emerging noise-induced hearing loss victims are adolescents who inappropriately use MP3 or MP3-like personal players (too long/too loud, using earphone-insert type headphones). Between 57% and 76% of tinnitus patients were shown to have noise-induced hearing loss. These, and a lot of other data, strongly indicate coexistence of both hearing dysfunctions. Based on the above data the authors put forward a hypothesis that the degree of hearing loss could negatively influence the severity of tinnitus. To test the hypothesis we used a retrospective study using data acquired from 531 tinnitus patients. This data were randomly collected on the admission of patients who reported to the day ward of Tinnitus Center at the Charité – Universitätsmedizin in Berlin between January 2008 and March 2010. The authors have analyzed general audiometric and tinnitus-oriented psychometric parameters.
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Complimentary effect of yogic sound resonance relaxation technique in patients with common neck pain
From: Int J Yoga 2010 Oct 16;3:18-25.
Studies have shown that conventional treatment methods with drugs, physiotherapy and exercises for common neck pain may be inadequate. Yoga techniques have been found to be effective complimentary therapies in chronic low back pain and also for stress reduction in other diseases. The aim of the study was to examine the complimentary role of a yogic relaxation called mind sound resonance technique in non-surgical management of common neck pain.
In this randomized controlled study, 60 patients with common neck pain were assigned to two groups (yoga, n=30) and (control, n=30). The yoga group received yogic mind sound resonance technique for 20 minutes in supine position after the conventional physiotherapy program for 30 minutes using pre-recorded audio CD and the control group had non-guided supine rest for 20 minutes (after physiotherapy), for 10 days. Mind sound resonance technique provides deep relaxation for both mind and body by introspective experience of the sound resonance in the whole body while repeating the syllables A, U, M and Om and a long chant (Mahamrityunjaya mantra) several times in a meaningful sequence. Both the groups had pre and post assessments using visual pain analog scale, tenderness scoring key, neck disability score (NDS) questionnaire, goniometric measurement of cervical spinal flexibility, and state and trait anxiety inventory-Y1 (STAI-Y1).
Mann-Whitney U test showed significant difference between groups in pain, tenderness, neck movements. Neck disability Index Scores (NDS) and state anxiety (STAI-Y1) showed higher reduction in yoga than that in the control group. Wilcoxon’s test showed a significant improvement in both groups on all variables. Yoga relaxation through mind sound resonance technique adds significant complimentary benefits to conventional physiotherapy for common neck pain by reducing pain, tenderness, disability and state anxiety and providing improved flexibility.
An integrative holistic model incorporating psychological and physical therapies for common neck pain will strengthen the rationalistic approach to treatment of common neck pain. The authors recommend that this simple procedure of using relaxation during and after the physiotherapy may be incorporated in all conventional therapy units round the globe in the management of common neck pain.
Pressure pain sensitivity maps of the neck-shoulder and the low back regions in men and women
From: BMC Musculoskelet Disord. 2010 Oct 12;11(1):234. [Epub ahead of print]
Chronic musculoskeletal pain causes reduced quality of life with loss of work and social networks. The use of quantitative diagnostic tests for mechanistic evaluation of musculoskeletal pain is important as many mechanisms such as soreness, hyperalgesia and spreading of pain/sensitization are involved. Chronic musculoskeletal pain is most often reported from the low back and shoulder regions. Further, a recent epidemiological study has emphasized a correlation between low back and neck pain in adults. Moreover, the prevalence of musculoskeletal disorders accompanied by pain is higher in women compared with men. Thus, the study of mechanical sensitivity and the spread of pain in the neck-shoulder (neck and shoulder) and low back regions can help characterizing these pain conditions in men and women.
Pressure pain thresholds are found to be reduced in whiplash and work-related musculoskeletal pain. In addition pressure pain thresholds are found to be lower in women as compared with men, and the cause of this difference is not fully understood but assumed to include both physiological, cultural and psychological factors.
Pressure pain algometry is a reliable technique for the assessment of mechanical pain sensitivity of deep somatic structures. However, pressure pain thresholds are found to vary along a muscle. Hence, recordings of pressure pain thresholds at many locations over a body region can delineate the extent of hyperalgesia. Recently, pressure pain threshold mapping of the trapezius muscle has underlined spatial pain sensitivity differences among subdivisions of the muscle indicating sensory partitioning.
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Neck Pain Is Often a Part of Widespread Pain and Is Associated With Reduced Functioning
From: Spine (Phila Pa 1976). 2010 Oct 11. [Epub ahead of print]
A Cross-sectional, population-based postal survey was performed to investigate the relationship between neck pain, pain in other sites and functioning. Neck pain is one of the most commonly reported musculoskeletal pain sites, and people with neck pain often report pain in other pain sites. Reduced functioning is associated with widespread pain. The relationship between neck pain with and without pain from other pain sites and functioning has not been described. In 2004, a questionnaire about musculoskeletal pain and functioning was sent to 7 birth cohorts in Ullensaker municipality in Norway, to which 3325 of 6108 persons (54.4%) responded. Musculoskeletal symptoms were registered using the Standard Nordic Questionnaire. Neck pain was categorized as localized neck pain (neck), regional neck pain (neck, shoulder, head, upper back), neck pain as part of scattered pain (1-3 other pain sites and not regional), or widespread pain (neck and ≥4 other pain sites). Functional status was assessed using the Norwegian Function Assessment Scale.
The 1-week prevalence of any neck pain was 34.4%. Localized neck pain was reported by only 1.4% of our population. Neck pain was most often regional (15.9%) or part of widespread pain (14.8%). People with neck pain as part of widespread pain had reduced function compared with any other group with neck pain. Localized neck pain was rare, and neck pain was almost always a part of either regional or widespread pain. Research on neck pain and functioning that do not assess other pain sites may miss a crucial dimension.
Accuracy of patients’ recall of temporomandibular joint pain and dysfunction after experiencing whiplash trauma: a prospective study
From: J Am Dent Assoc. 2010 Jul;141(7):879-86
Researchers have conducted studies regarding whiplash induced temporomandibular joint (TMJ) pain and dysfunction mainly under the presumption that patients’ memory of symptoms remains accurate across time. In this prospective study, the authors aimed to determine the frequency of patients’ inaccurate retrospective reports of TMJ pain and dysfunction after whiplash trauma.
The authors assessed TMJ pain and dysfunction in 60 patients consecutively seen in a hospital emergency department directly after the patients experienced whiplash trauma in rear-end automobile accidents. They followed up with 59 patients one year later. The participants completed a self-administered questionnaire followed by a comprehensive interview during both examinations. The study group consisted of the 40 patients who reported previous or current TMJ pain, dysfunction or both at either examination or at both examinations.
The agreement between each patient’s inceptive and retrospective reports of TMJ pain and dysfunction yielded a kappa value of 0.41 (95 percent confidence interval [CI] 0.18-0.64). Sixteen patients (40 percent, 95 percent CI 25-57 percent) had inaccurate recall. Recollection errors were addition, omission, and forward and backward telescoping. Seven patients incorrectly referred symptom onset to the accident.
The high frequency of inaccurate recall of TMJ pain and dysfunction one year after whiplash trauma implies that clinicians and researchers should interpret with caution the results of previous studies that relied on retrospective data regarding whiplash induced TMJ pain and dysfunction. To achieve valid long-term evaluations in clinical research, the patient’s TMJ status should be established at the time of an accident.
