Assessment of disc injury in subjects exposed to long-term whole-body vibration.
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Long-term exposure to whole-body vibration is known to increase the risk of low back problems. The chain of events leading from repeated loading of the lumbar spine to back complaints and the exact nature of the vibration-induced damage are, however, obscure. Fluid in- and outflow as well as viscoelastic deformation are important aspects of the physiological function of the lumbar disc. Precision measurement of stature, termed 'stadiometry', has previously been applied in healthy subjects to document changes in disc height in relation to the load on the lumbar spine. The purpose of this study was to explore the relation between spinal loading and stature in a cohort of 20 subjects with long-term exposure to whole-body vibration. If the change of stature (and thus the change of disc height) caused by changes in spinal loading differed between exposed and normal subjects, this would point to vibration-induced changes in structure and material properties of the discs. For this purpose, four hypotheses were tested: (1) the viscoelastic deformation and fluid exchange of intervertebral discs during phases of spinal loading and unloading differs from normal; (2) the water content of lumbar discs of subjects exposed to long-term whole-body vibration deviates from normal; (3) the mean disc height of the lumbar spine depends on the total time of vibration exposure; (4) repeated loading influences trabecular bone density of vertebrae in the lumbar spine. A cohort of 20 operators of heavy earth-moving machinery was enrolled. Back complaints suspected to be due to long-term exposure (mean 17.6 +/- 2.1 years) to whole-body vibration and application for early retirement were the selection criteria used. Change of stature during a regular 8-h shift and change of stature in standing, carrying and sitting activities were measured. The stadiometric investigations were supplemented by magnetic resonance imaging (MRI) of the lumbar spine to assess whether the water content of the discs exhibited deviations from normal. In addition, quantitative computed tomography (QCT) was performed to assess whether the trabecular bone density of the third lumbar vertebra deviated from normal. The results showed no significant difference in change of stature while standing, carrying or sitting between exposed machine operators and non-exposed operators. Likewise, MRI examinations revealed no significant differences in the water content of the discs averaged over the lumbar spine. In addition, QCT examinations revealed no significant difference in the trabecular bone density of the third lumbar vertebra. The study thus revealed no significant difference between a cohort with long-term exposure and non-exposed controls with respect to viscoelastic properties of discs as determined by stadiometry, average water content of lumbar discs and trabecular bone density of L3. (+info)
Recurrent pain after lumbar discectomy: the diagnostic value of peridural scar on MRI.
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The association between peridural scarring and recurrent pain after lumbar discectomy is much debated. A recently published study found that patients with extensive peridural fibrosis were 3.2 times more likely to experience recurrent radicular pain than those with less extensive scarring. This finding may lead to an overestimation of peridural fibrosis in clinical practice. In a retrospective study we analyzed the records of 53 patients who underwent a lumbar MRI because of recurrent pain after first unilateral microdiscectomy. Patients were classified as those with radicular or non-radicular pain according to history and clinical findings. The diagnosis was confirmed by spinal anesthetic block. The extension of scarring was compared between the two groups of patients. The amount of epidural fibrosis was examined on contrast-enhanced MRI in axial slices subdivided into four quadrants. The amount of fibrosis was divided into four stages in each affected quadrant. We found no differences regarding the amount of peridural fibrosis between patients with radicular pain and patients with non-radicular pain. We conclude that the extent of peridural scarring as defined by MRI is of minor value in the differential diagnosis of recurrent back and leg pain after lumbar microdiscectomy. (+info)
Prolonged low-back pain in young athletes: a prospective case series study of findings and prognosis.
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We investigated the prognosis of low-back pain and the association of clinical symptoms and anatomic findings among young athletes. Consecutive patients, aged between 12 and 18 years, who had low-back pain that had interfered with their training for at least 4 weeks were included in the case series. All the patients participated in a standardized interview and clinical examination, and plain radiographs and magnetic resonance images were also obtained. Most patients also participated in technetium bone scan examination. In 15 out of 19 subjects there were anatomic abnormalities that corresponded with the location and type of clinical symptoms. Twelve subjects had changes in the disk-vertebral end plate complex and eight had a positive bone scan indicative of posterior vertebral arch stress reaction. Six out of eight boys and two out of 11 girls had stress reaction (P = 0.043). Restriction of painful activities was recommended to all subjects, restriction of activities and the use of a dynamic low-back brace for the first 3 months was recommended to patients with posterior vertebral arch stress reaction. The self-reported intensity of low-back pain (scale 0-100) among all the patients was 69 +/- 16 (mean +/- SD) at baseline and 18 +/- 21 at the 1-year follow-up (P < 0.0001). In conclusion, the reasons for prolonged back pain among young athletes are usually established by imaging studies. A knowledge of anatomic abnormalities may help in tailoring training programmes and avoiding the progression of changes during growth. Simple restriction of painful activities usually leads to good recovery. (+info)
Recombinant bone morphogenetic protein-7 as an intracorporal bone growth stimulator in unstable thoracolumbar burst fractures in humans: preliminary results.
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The study presented here is a pilot study in five patients with unstable thoracolumbar spine fractures treated with transpedicular OP-1 transplantation, short segment instrumentation and posterolateral fusion. Recombinant bone morphogenetic protein-7 in combination with a collagen carrier, also referred to as OP-1, has demonstrated ability to induce healing in long-bone segmental defects in dogs, rabbits and monkeys and to induce successful posterolateral spinal fusion in dogs without need for autogenous bone graft. Furthermore OP-1 has been demonstrated to be effective as a bone graft substitute when performing the PLIF maneuver in a sheep model. Five patients with single-level unstable burst fracture and no neurological impairment were treated with intracorporal OP-1 transplantation, posterior fixation (USS) and posterolateral fusion. One patient with osteomalacia and an L2 burst fracture had an additional intracorporal transplantation performed proximal to the instrumented segment, i.e. OP-1 into T 12 and autogenous bone into T 11. Follow-up time was 12-18 months. On serial radiographs, Cobb and kyphotic angles, as well as anterior, middle and posterior column heights, were measured. Serial CT scans were performed to determine the bone mineral density at fracture level. In one case, radiographic and CT evaluation after 3 and 6 months showed severe resorption at the site of transplantation, but after 12 months, new bone had started to fill in at the area of resorption. In all cases there was loss of correction with regard to anterior and middle column height and sagittal balance at the latest follow-up. These preliminary results regarding OP-1 as a bone graft substitute and stimulator of new bone formation have been disappointing, as the OP-1 device in this study was not capable of inducing an early sufficient structural bone support. There are indications to suggest that OP-1 application to a fracture site in humans might result in detrimental enhanced bone resorption as a primary event. (+info)
Short segment fixation of thoracolumbar burst fractures without fusion.
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There continues to be controversy surrounding the management of thoracolumbar burst fractures. Numerous methods of fixation have been described for this injury, but to our knowledge, spinal fusion has always been part of the stabilising procedure, whether this involves an anterior or a posterior approach. Apart from an earlier publication from this centre, there have been no reports on the use of internal fixation without fusion for this type of fracture. The aim of the study was to determine the outcome of patients with thoracolumbar burst fractures who were treated with short segment pedicle screw fixation without fusion. This is a retrospective review of 28 consecutive patients who had short segment pedicle screw fixation of thoracolumbar burst fractures without fusion performed between 1990 and 1993. All patients underwent a clinical and radiological assessment by an independent observer. Outcome was measured using the Low Back Outcome Score. The minimum follow-up period was 2 years (mean 3.1 years). Fifty percent of patients achieved an excellent result with the Low Back Outcome Score, while 12% were assessed as good, 20% fair and 16% obtained a poor result. The only significant factor affecting outcome was the influence of a compensation claim (P < 0.05). The implant failure rate (14% of patients) and the clinical outcome was similar to that from series where fusion had been performed in addition to pedicle screw fixation. The results of this study support the view that posterolateral bone grafting is not necessary when managing patients with thoracolumbar burst fractures by short segment pedicle screw fixation. (+info)
1Alpha-hydroxyvitamin D3 prevents the decrease of bone mineral density in lactating beagles.
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We assessed the change of bone mineral density (BMD) in lactating beagles with dual energy X-ray absorptiometry (DXA) and the preventive effect of 1alpha-hydroxyvitamin D3 (1alpha(OH)D3) on the BMD. Beagles, two to five years old, were used for detecting the time course change of BMD. Since the coefficient of variation (CV(%)) on detecting lumber vertebral (L2-L4) and tibial BMD by DXA was about 0.5%, DXA was useful to detect the change of BMD in beagles. There was a marked decrease in vertebral BMD during lactational period in the control group. The BMD levels after weaning were found to reverse to the initial level at mating. The same tendency was observed in tibial BMD as vertebral BMD, though the BMD changes were not marked. Beagles were administered at a dose of 0.1 microg/kg of 1alpha(OH)D3 three times in a week, and it was found to suppress the decrease in vertebral BMD during the breast feeding period. Also, the administration of 1alpha(OH)D3 promoted the prevention of decreased BMD during lactation both in vertebrae and tibiae. Significant effects of 1alpha(OH)D3 administration on tibial BMD were not observed. No adverse effects, such as hypercalcemia and hypercalciuria, were observed during the experimental period. Therefore, DXA was useful for detecting the changes of BMD in lactating beagles and the change of BMD was marked in lumber vertebrae, which are rich in trabecular bone. The preventive effect of 1alpha(OH)D3 on the decrease of BMD during the lactation period was observed in beagles. (+info)
Relationship of Schmorl's nodes to vertebral body endplate fractures and acute endplate disk extrusions.
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BACKGROUND AND PURPOSE: Literature regarding clinical pain syndromes associated with acute, traumatic Schmorl's nodes (SNs) is limited. Our purpose was to determine whether an SN could be related to a previous traumatic event producing either acute SN or a vertebral endplate fracture. METHODS: Two neuroradiologists independently reviewed initial and follow-up MR examinations of 14 patients with a clinical diagnosis of acute, symptomatic thoracolumbar SNs or vertebral body endplate fractures that evolved into SNs to evaluate marrow edema, signal intensity, margin definition, presence of intravertebral extruded disk material, and pattern of contrast enhancement. RESULTS: Edema of the affected vertebral body, adjacent to an endplate without wedging or collapse, was observed on the initial MR images in all cases. The initial MR images of six (43%) of 14 patients exhibited only edema of the marrow immediately adjacent to the endplate without wedging or collapse. The MR images obtained at the time of follow-up showed subsequent formation of a chronic and eventually asymptomatic SN for all six patients. The initial MR images of eight (57%) of the 14 patients showed the typical appearance of acute SNs with marrow edema of the affected vertebra. The contrast-enhanced images of three patients manifested enhancement of the invaginated disk material in three (100%) of three cases and enhancement of the surrounding vertebral body in one case (33%). Six (43%) of 14 patients had acute typical compression fracture of a vertebral body of at least one additional level. CONCLUSION: Most (57%) of the SNs in this series could be traced to episodes of significant, sudden-onset, localized, nonradiating back pain and tenderness for which the MR images showed SNs surrounded by vertebral body marrow edema. The remaining SNs (43%) were not immediately apparent as SNs and manifested only as vertebral body edema representing endplate fracture but did evolve into classical chronic SNs that follow-up imaging revealed. (+info)
The relationship of lumbar flexion to disability in patients with low back pain.
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BACKGROUND AND PURPOSE: Physical therapists routinely assess spinal active range of motion (AROM) in patients with low back pain (LBP). The purpose of this study was to use 2 approaches to examine the relationship between impairment of lumbar spine flexion AROM and disability. One approach relied on the use of normative data to determine when an impairment in flexion AROM was present. The other approach required therapists to make judgments of whether the flexion AROM impairment was relevant to the patient's disability. SUBJECTS: Fifteen physical therapists and 81 patients with LBP completed in the study. METHODS: Patients completed the Roland-Morris Back Pain Questionnaire (RMQ), and the therapists assessed lumbar spine flexion AROM using a dual-inclinometer technique at the initial visit and again at discharge. RESULTS: Correlations between the lumbar flexion AROM measure and disability were low and did not vary appreciably for the 2 approaches tested. CONCLUSION AND DISCUSSION: Measures of lumbar flexion AROM should not be used as surrogate measures of disability. Lumbar spine flexion AROM and disability are weakly correlated, suggesting that flexion AROM measures should not be used as treatment goals. (+info)