Neck Solutions

STIR sequence for depiction of degenerative changes in posterior stabilizing elements in patients with lower back pain

From: AJR Am J Roentgenol. 2008 Oct;191(4):973-9

The aims of this study were to investigate whether degenerative posterior paraspinal changes are a cause of lower back pain and to determine the age and sex related distribution of these changes on MR images acquired with a STIR (Short T1 Inversion Recovery) sequence. The lumbar MRI findings of 372 patients (141 men, 231 women; mean age, 51.2 years) with nonradicular lower back pain and of 249 healthy persons acting as controls (126 men, 123 women; mean age, 49.3 years) were analyzed. The sagittal STIR sequence was used for all MRI examinations. Presence of interspinous ligament edema, facet joint effusion, neocysts, paraspinal muscle edema, subcutaneous edema, disc herniation, and disc degeneration was evaluated, and the incidence of each finding was determined. All findings were grouped according to age and sex.

The incidences of facet joint effusion, interspinous ligament edema, neocyst formation, and paraspinal muscle edema were found to be statistically significantly higher in patients with lower back pain than in controls. The incidences of intervertebral disc degeneration, disc herniation, and subcutaneous edema in persons with and those without lower back pain were similar. Intervertebral disc degeneration, disc herniation, subcutaneous edema, and muscle edema were found to increase with age in both persons with and those without symptoms.

• Degenerative changes in the posterior paraspinal structures were found in a higher percentage of subjects with lower back pain than in controls.

Use of a STIR sequence with homogeneous fat suppression facilitates visualization of these changes.

Reorganization of the motor cortex is associated with postural control deficits in recurrent low back pain

From: Brain. 2008 Aug;131(Pt 8):2161-71. Epub 2008 Jul 18

Many people with recurrent low back pain have deficits in postural control of the trunk muscles and this may contribute to the recurrence of pain episodes. However, the neural changes that underlie these motor deficits remain unclear. As the motor cortex contributes to control of postural adjustments, the current study investigated the excitability and organization of the motor cortical inputs to the trunk muscles in 11 individuals with and without recurrent low back pain. EMG activity of the deep abdominal muscle, transversus abdominis, was recorded bilaterally using intramuscular fine wire electrodes. Postural control was assessed as onset of transversus abdominis EMG during single rapid arm flexion and extension tasks. Motor thresholds for transcranial magnetic stimulation were determined for responses contralateral and ipsilateral to the stimulated cortex. In addition, responses of transversus abdominis to transcranial magnetic stimulation over the contralateral cortex were mapped during voluntary contractions at 10% of maximum. Motor thresholds and map parameters, centre of gravity and volume, were compared between healthy and low back pain groups. The centre of gravity of the motor cortical map of transversus abdominis in the healthy group was approximately 2 cm anterior and lateral to the vertex, but was more posterior and lateral in the low back pain group. The location of the centre of gravity and the map volume were correlated with onset of transversus abdominis EMG during rapid arm movements. Furthermore, the motor thresholds needed to evoke ipsilateral responses was lower in the low back pain group, but only on the less excitable hemisphere. These findings provide preliminary evidence of reorganization of trunk muscle representation at the motor cortex in individuals with recurrent low back pain, and suggest this reorganization is associated with deficits in postural control.

The Influence of Posture and Loading on Interfacet Spacing: An Investigation Using Magnetic Resonance Imaging on Porcine Spinal Units

From: Spine. 2008 Sep 15;33(20):E728-E734

Axial rotation has frequently been identified as a risk factor for the development of low back injury in epidemiological investigations. However, the mechanism responsible for this increased risk has not been directly quantified. Increased axial rotation motion is used clinically to indicate instability and has been implicated as a potential cause of low back pain. Recently, it has been demonstrated that larger axial twist angles can be achieved when coupled with forward flexion in vivo. The range of twist motion permitted in the spine has been calculated as a function of the distance between the articulating surfaces of the facets using kinematic data and computed tomography reconstructions, but the tracking of the facet joint in coupled postures has not been reported in detail. Whether the reason epidemiological studies identify axial twist as a risk factor for low back pain is due to a shift in the load distribution from the facet joint to the intervertebral disc or other spinal tissues has not been determined. Using finite element modeling, it was reported that the primary factor in determining the relative effectiveness of the facet joints in resisting rotation was the amount of interfacet spacing. Changes in facet joint spacing in different postures could lead to errors in diagnosis and subsequent treatments prescribed when magnetic imaging technologies are used to diagnose spinal instability. Can posture or loading history cause a difference in the mechanics of the spine? This question is relevant to address concepts such as instability, spine mechanics, and injury mechanisms, and can be explored using an in vitro approach combined with current medical imaging technologies. In vitro investigations permit the necessary control and accessibility necessary to examine the facet joint behavior when the spine is in coupled postures. Therefore, quantifying the effect of posture and loading history on interfacet spacing would provide important information in helping to resolve some of these issues.

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Advances in susceptibility genetics of intervertebral degenerative disc disease

From: Int J Biol Sci. 2008 Sep 2;4(5):283-90

The traditional view that the etiology of lumbar disc herniation is primarily due to age, gender, occupation, smoking and exposure to vehicular vibration dominated much of the last century. Recent research indicates that heredity may be largely responsible for the degeneration as well as herniation of intervertebral discs. Since 1998, genetic influences have been confirmed by the identification of several genes forms associated with disc degeneration. These researches are paving the way for a better understanding of the biologic mechanisms. Now, many researchers unanimously agree that lumbar disc herniation appears to be similar to other complex diseases, whose etiology has both environmental and hereditary influence, each with a part of contribution and relative risk. Then addressing the etiological of lumbar disc herniation, it is important to integrate heredity with the environment factors.

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Health problems related to working in extreme cold conditions indoors

From: Int J Circumpolar Health. 2008 Jun;67(2-3):279-87

To identify health problems among workers performing cleaning, maintenance and machine operation tasks inside cold storage rooms with temperatures between -43 degrees C and -62 degrees C in a freeze drying coffee company. All 24 workers working inside the cold stores participated in the study. A questionnaire about cold related health problems and the standardized Nordic questionnaire assessing muscle complaints were completed by all exposed workers. A physical examination was performed on each worker.

The most relevant cold related health problem was episodic finger symptoms (50%), followed by respiratory symptoms (21%), peripheral circulation symptoms (20%), and repeated pain in the musculoskeletal system (12%). Two subjects had a previous diagnosis of Raynaud’s phenomenon. The prevalence of musculoskeletal complains in the neck and low back was 21% in each. The prevalence found for various complaints among the freeze drying coffee workers implies that the cold conditions inside cold stores may present a real risk of cold related health problems and, due to lowered concentration level, for injuries, too. Greater efforts should be made to minimize the cold exposure by designing automation processes to prevent continuous exposure to cold during freeze drying process. In addition, improving the cold protective clothing and guaranteeing its appropriate use will reduce health risks.

Modic changes, possible causes and relation to low back pain

From: Med Hypotheses. 2008;70(2):361-8. Epub 2007 Jul 10

In patients with low back pain it is only possible to diagnose a small proportion, (approximately 20%), on a pathoanatomical basis. Therefore, the identification of relevant low back pain subgroups, preferably on a pathoanatomical basis, is strongly needed. Signal changes on MRI in the vertebral body marrow adjacent to the end plates also known as Modic changes are common in patients with low back pain (18-58%) and is strongly associated with low back pain. In asymptomatic persons the prevalence is 12-13%. Modic changes are divided into three different types. Type 1 consists of fibro vascular tissue, type 2 is yellow fat, and type 3 is sclerotic bone. The temporal evolution of Modic changes is uncertain, but the time span is years. Subchondral bone marrow signal changes associated with pain can be observed in different specific infectious, degenerative and immunological diseases such as osseous infections, osteoarthritis, ankylosing spondylitis and spondylarthritis. In the vertebrae, Modic changes are seen in relation to vertebral fractures, spondylodiscitis, disc herniation, severe disc degeneration, injections with chymopapain, and acute Schmorl’s impressions. The aim of this paper is to propose two possible pathogenetic mechanisms causing Modic changes. These are: A mechanical cause: Degeneration of the disc causes loss of soft nuclear material, reduced disc height and hydrostatic pressure, which increases the shear forces on the endplates and micro fractures may occur. The observed Modic changes could represent oedema secondary to the fracture and subsequent inflammation, or a result of an inflammatory process from a toxic stimulus from the nucleus pulposus that seeps through the fractures. A bacterial cause: Following a tear in the outer fibres of the annulus e.g. disc herniation, new capilarisation and inflammation develop around the extruded nuclear material. Through this tissue it is possible for anaerobic bacteria to enter the anaerobic disc and in this environment cause a slowly developing low virulent infection. The Modic changes could be the visible signs of the inflammation and oedema surrounding this infection, because the anaerobic bacteria cannot thrive in the highly aerobic environment of the Modic changes type 1. Perspectives: One or both of the described mechanisms can - if proven - be of significant importance for this specific subgroup of patients with low back pain. Hence, it would be possible to give a more precise and relevant diagnosis to 20-50% of patients with low back pain and enable in the development of efficient treatments which might be antibiotics, special rehabilitation programmes, rest, stabilizing exercise, or surgical fixation, depending on the underlying cause for the Modic changes.

Are Children’s Backpack Weight Limits Enough?: A Critical Review of the Relevant Literature

From: Spine:Volume 29(19)1 October 2004pp 2184-2190

Back pain is a widespread musculoskeletal condition in the adult population. This problem has stretched into the younger age groups and has become a condition often experienced by adolescents. The overall lifetime prevalence of low back pain in children has been reported as high as 65%.1 Other lifetime prevalence reports in children (less than 18 years) are more modest and are reported between 30% and 50%. Although the debate continues, some researchers hypothesize that use of heavy backpacks may contribute to the high reports of back pain in children. This hypothesis has led to recommended load limits of 10% to 15% of a child’s body weight by many health professional associations. Although these weight limits have been recommended in several states or countries, controversy continues to exist in the literature about the effects of backpack weight on back pain in children. The purpose of this review is to evaluate the literature that has contributed to the recommended weight limits for children’s backpacks. The current use of backpacks by children, injuries related to backpack use, the physiologic and biomechanical findings that were used to develop the recommended weight limits, and the need for research into children’s backpack design will be discussed.

Studies indicate that the incidence of backpack use by school children in the developed world is at least 90%. The weight carried by students varies by region and day of the week. Although the average loads vary greatly between studies, the majority of reports indicate that the loads carried by students are greater than the recommended limits. A study found that the average daily load of Italian students over a week ranged from 22.0% body weight to 27.5% body weight with one student who carried 46.2% body weight. In this group, 34.8% carried more than 30% of their body weight. Other studies report more modest loads ranging from 10.3% body weight to 20% body weight. Although these values are less extreme, the majority of students surveyed are still above the recommended limits. Only two studies were found where the mean load was less than 10% body weight.

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Trunk muscle onset and cessation in golfers with and without low back pain

From: J Biomech. 2008 Aug 19; [Epub ahead of print]

The knowledge of the onset and cessation timing of the paraspinal muscles that surround the lumbar spine is an important area of research for the understanding of low back pain. This study examined the timing of the erector spinae and external oblique muscle activity in a group of golfers with and without low back pain. The study compared the results of surface electromyography measurements for two groups of golfers. Twelve male golfers who had reported a mild or greater level of pain in the lower back that was experienced while playing golf were examined. A further fifteen male golfers who had reported no history of lower back pain in the previous 12 months were recruited as controls. The results showed that the low back pain golfers switched on their erector spinae muscle significantly in advance of the start of the backswing. This finding was not evident in the group who did not have low back pain symptoms. Low back pain golfers, therefore, may use the erector spinae muscle as a primary spinal stabiliser instead of the stronger deeper muscles such as transversus abdominis and multifidus. These results may have important implications for conditioning programmes for golfers with low back pain.

Kyphosed seated postures: extending concepts of postural health beyond the office

From: J Occup Rehabil. 2008 Mar;18(1):35-45. Epub 2008 Feb 7

The harmful effects of sustained sitting and the health of the spine are well documented. The focus of much of this investigation has been sedentary occupations. However, how people sit during leisure hours can impact on the health of the spine both in and out of working hours. In this study a literature search was conducted using Amed, Cinahl and OVID Medline databases. Papers published between 1985 and 2007 were selected for review. These included epidemiological and experimental studies that explored the relationships between seated postures and health of the lumbar spine. Until recently there was confusion in the scientific literature as to which seated postures were least harmful: lordosed or kyphosed. This article reviews and analyses these conflicts in relation to leisure sitting.

Analysis of the literature demonstrates that kyphosed seated postures when sustained are more harmful to the health of the lumbar spine than lordosed seated postures. There is a misconception amongst designers and users of leisure seating that kyphosed relaxed postures are comfortable and that comfort equates with health. It is argued that sustained kyphosed postures are insidiously harmful to the spine in that they may contribute to disc degeneration in the absence of pain. Sustained kyphosed postures also adversely affect spinal ligaments, muscles and joints and lead to neuromuscular and cumulative trauma disorders and loss of spinal stability. Recent research demonstrates that postures popularly assumed in recreational or leisure seating lead to cumulative damage to soft tissues of the spine. These effects may still be present at the commencement of the following work day. In the prevention of work disability caused by sustained sitting, health professionals must consider the impact of leisure seating design and recreational sitting behaviour.

Sitting with adjustable ischial and back supports: biomechanical changes

From: Spine. 2003 Jun 1;28(11):1113-21

Low back pain is acute or chronic pain involving the lumbosacral, buttock, and/or thigh. Discogenic low back pain is aggravated by the sitting position, which is necessary in many occupations and daily activities. About 100 million workdays are lost annually in the United States due to low back pain. Despite improved knowledge and health care resources for spinal pathology, chronic disability resulting from nonspecific low back pain is rising exponentially. Although the causes of discogenic low back pain are multifactorial and complex, sitting postures could increase stresses within the disc and contribute to disc degeneration and pain. Two major occupational risk factors are static muscle load and flexed curvature of the lumbar spine; both are involved in seated work tasks.

During sitting, the head, arm and trunk weight is carried mainly by the ischial tuberosities and surrounding tissues. High pressure at the tuberosities is closely associated with high load to the spine. A significant mechanical spine loading is associated with low back pain resulting from trunk muscle coactivation. Ischial and lower back interface pressure vary with different sitting postures and body positioning. Repositioning of the lumbar support to redistribute the interface pressure and load is essential in preventing low back pain associated with inappropriate sitting in a working environment. Therefore, a device that decreases the sitting pressure and load carried by the ischial tuberosity may decrease forces within the disc and associated degeneration and pain.

Physiologic lumbar lordosis in the standing position ranges from 40° to 60°, with the lordosis occurring mainly at S1-L5 and L4-L5, and with the sacral inclination ranging from 30° to 40°. Compared to standing or lying supine, sitting could cause the pelvis to rotate posteriorly, resulting in decreased sacral inclination and lumbar lordosis and increased forces at the discs. A number of investigators have reported interaction between low back pain and biomechanical changes such as decreased lumbar lordosis, malalignment of lumbar curvature, and narrowing of disc spaces. Williams et al reported that use of a lumbar roll that increased lumbar lordosis reduced low back pain, and the chair backrest also helps increase the lumbar lordosis and decrease intradiscal pressure.

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