Historical perspectives 2000.
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History, 20th Century↗
Biomedical subjects
J Dvorak
Publications and source records attributed to J Dvorak.
Positional MR imaging of the lumbar spine: does it demonstrate nerve root compromise not visible at conventional MR imaging?
PURPOSE: To evaluate whether positional magnetic resonance (MR) images of the lumbar spine demonstrate nerve root compromise not visible on MR images obtained with the patient in a supine position (conventional MR images). MATERIALS AND METHODS: Thirty patients with chronic low back pain unresponsive to nonsurgical treatment and with disk abnormalities but without compression of neural structures were included. Positional MR images were obtained by using an open-configuration, 0.5-T MR imager with the patients seated and with flexion and extension of their backs. The disk and nerve root were related to the body position. Nerve root compression and foraminal size were correlated with the patient's symptoms, as assessed with a visual analogue scale. RESULTS: Nerve root contact without deviation was present in 34 of 152 instances in the supine position, in 62 instances in the seated flexion position, and in 45 instances in the seated extension position. As compared with the supine position, in the seated flexion position nerve root deviation decreased from 10 to eight instances; in the seated extension position, it increased from 10 to 13 instances. Nerve root compression was seen in one patient in the seated extension position. Positional pain score differences were significantly related to changes in foraminal size (P =.046) but not to differences in nerve root compromise. CONCLUSION: Positional MR imaging more frequently demonstrates minor neural compromise than does conventional MR imaging. Positional pain differences are related to position-dependent changes in foraminal size.
Adult↗
A randomized clinical trial of three active therapies for chronic low back pain.
STUDY DESIGN: A randomized clinical trial. OBJECTIVES: To examine the relative efficacy of three active therapies for chronic low back pain. SUMMARY OF BACKGROUND DATA: There is much evidence documenting the efficacy of exercise in the conservative management of chronic low back pain, but many questions remain regarding its exact prescription and method of application. The most successful method must be identified to enable refinement of future rehabilitation programs to target the specific needs of the patient with chronic low back pain and the budget of the healthcare provider. METHODS: One hundred forty-eight patients with chronic low back pain were randomized to one of the following treatments, which they attended twice a week for 3 months: 1) modern active physiotherapy, 2) muscle reconditioning on training devices, or 3) low-impact aerobics. Pretherapy and posttherapy, objective measurements of lumbar mobility were performed, and questionnaires were administered inquiring about self-rated pain and disability, and psychosocial factors. Similar questionnaires were administered 6 months after therapy. The data were analyzed using the intention-to-treat principle. RESULTS: Of the 148 patients, 16 (10.8%) dropped out of the therapy. One hundred thirty-seven questionnaires (93%) were available for analysis at all three time points. After therapy, significant reductions were observed in pain intensity, frequency, and disability; Fear-Avoidance Beliefs about physical activity (FABQactivity); and "praying/hoping," "catastrophizing," and "pain behavior" coping strategies--each with no group differences in the extent of the response. These effects were maintained over the subsequent 6 months, with the exception of disability and FABQactivity for the physiotherapy group. There were small but significant posttherapy increases in lumbar mobility, with aerobics and devices showing a greater response than physiotherapy. CONCLUSION: The general lack of treatment specificity suggests that the main effects of the therapies were educed not through the reversal of physical weaknesses targeted by the corresponding exercise modality, but rather through some "central" effect, perhaps involving an adjustment of perception in relation to pain and disability. The direct costs associated with administering physiotherapy were three times as great, and devices four times as great, as those for aerobics. Administration of aerobics as an efficacious therapy for chronic low back pain has the potential to relieve some of the huge financial burden associated with the condition.
Adult↗
[Manual therapy in lumbo-vertebral syndromes].
Based upon the shortly presented survey among the members of the Swiss Medical Association for Manual Medicine, the low back pain problems are approached by the means of manual therapy on average 805 times per year and physician. On average each case with low back pain is treated 1,4 times by a general practitioner with experience in manual medicine while specialists who are dealing with more complex cases on average 4 to 5 times. The functional disorders of the lumbar spine treated by manual therapy are superior to the physiotherapy approach or in comparison with a "placebo group" (information by general practitioner about low back pain and application of medication). An appropriate indication for manual therapy is relevant to avoid or reduce the possible risk of the treatment procedure. The physician who performs the manual therapy has to know the limits of the method. Also the knowledge of contraindications for manual therapy will reduce the incidence of possible complication. However based upon the survey among the swiss association the side effects and complications due to manual therapy of the lumbal spine are extremely seldom.
Humans↗
Histology of the ligamentum flavum in patients with degenerative lumbar spinal stenosis.
The degree of calcification as well as the structural changes of the elastic fibres in the ligamentum flavum in patients with degenerative lumbar spinal stenosis were evaluated and the results were compared to those of patients without spinal stenosis. In 21 patients (13 male, 8 female) with lumbar spinal stenosis the ligamentum flavum was removed, histologically processed and stained. The calcification, the elastic/collagenous fibre ratio as well as the configuration of the fibres were evaluated with an image analyzing computer. As a control group, 20 ligaments of 10 human corpses were processed in the same way. The results were statistically analysed using the Mann-Whitney-Wilcoxon test (alpha = 0.05) and the t-test (alpha = 0.05). Nearly all the ligaments of patients with lumbar spinal stenosis were calcified (average 0.17%, maximum 3.8%) and showed relevant fibrosis with decreased elastic/collagenous fibre ratio. There was a significant correlation between age and histological changes (P<0.05). In the control group we only found minimal calcification in 3 of 20 segments (average 0.015%). No relevant fibrosis was found and the configuration of elastic fibres showed no pathologic changes. The results of this study illustrate the important role of histological changes of the ligamentum flavum for the aetiology of lumbar spinal stenosis.
Adult↗
Relation between neuropsychological and neuroimaging findings in patients with late whiplash syndrome.
OBJECTIVES: The interpretation of long term cognitive impairment after whiplash injury is still a problem for many physicians. On the grounds of nuclear medicine findings previous research speculated that brain damage is responsible for cognitive problems of patients with whiplash. To test this hypothesis the relation between neuroimaging and neuropsychological findings was analysed. METHODS: Twenty one patients (11 women, 10 men, mean age 42.2 (SD 8.6) years) with the late whiplash syndrome (average interval of trauma 26.1 (SD 20.7) months) referred for diagnostic action to the Department of Neurology were investigated. Assessment included computer assisted assessment of working memory and divided attention, neuroimaging (by the means of [99mTc]-HMPAO-SPECT, [15O]-H2O-PET and [18F]-FDG-PET), testing of emotional functioning (depression and anxiety ratings), and pain intensity at the time of testing. RESULTS: On average, scoring on tests of cognitive functioning was very low. However, no significant correlations were found between regional perfusion or metabolism in any brain area and the scores of divided attention or working memory. By contrast, significant relations were found between indices of impaired emotional functioning (state anxiety) and divided attention. In addition, low scoring in divided attention was significantly correlated with pain intensity at the time of testing. CONCLUSIONS: The present data do not provide evidence of a significant relation between detectable morphological or functional brain damage and impaired cognitive performance in the late whiplash syndrome. Results indicate triggering of emotional and cognitive symptoms on the basis of initial injury of the cervical spine.
Adult↗
Translaminar screw fixation of the lumbar and lumbosacral spine. A 5-year follow-up.
STUDY DESIGN: In a retrospective study, the long-term results of translaminar facet screw fixation of the lumbar and lumbosacral spine are reviewed. OBJECTIVES: To evaluate the clinical results, fusion rates and complications of this posterior fusion technique in various conditions of the lumbar spine. SUMMARY OF BACKGROUND DATA: Posterior fusion of the lumbar and lumbosacral spine is one of the possible methods to relieve pain and eliminate instability in degenerative conditions. Data in the literature support the use of internal fixation to optimize the rate of fusion. METHODS: Posterior lumbar and lumbosacral fixation with translaminar screws and fusion in 173 patients with degenerative changes with or without compressive syndromes including failed back syndromes, monosegmental hypermobilities, and posttraumatic conditions were investigated. Fixation and fusion with translaminar screws was performed in 57% monosegmentally, in 40% across two segments and in 2% over three segments. Decompressive surgery was performed in addition in 52% and nucleotomy in 30% of the cases. Clinical and radiologic assessment with flexion/extension x-rays was performed in 145 (83%) patients by two independent orthopedic surgeons. After an average follow-up of 68 months (range, 52-83). RESULTS: Ninety-four percent of the patients showed solid bony fusion in the radiologic follow-up. Loosening of the screws was noted in 3%, and two screws were broken without apparent motion on the functional x-rays. Pain scores decreased from 7.6 before surgery to 2.9 after surgery on a 10-point pain scale. The results were further analyzed according to Stauffer and Coventry with 99 good results, 70 satisfactory results, and 4 bad results. CONCLUSIONS: Translaminar screw fixation offers an immediate postoperative stability of the lumbar and lumbosacral spine and enhances fusion. In the present series no neurologic complications were noted. It represents a useful and inexpensive technique for short segment fusion of the nontraumatic lumbar and lumbosacral spine.
Adult↗
[Sacral block: indications and effectiveness].
It has been shown that during injection of 17 to 20 ml local anesthetics combined with a corticosteroid via the hiatus canalis sacralis that the solution is distributed up to the level of the thoraco-lumbar junction. The indication for therapeutical peridural injection are radicular symptoms as a result of disc herniation, foraminal stenosis as well as neurogenic claudicatio. Contraindications are anticoagulation, local infection as well as suspicion of systemic inflammatory disease of the peripheral nervous system. With proper technique and adequate desinfection, complications and side effects are very rare.
Anesthesia, Epidural↗
Simulation of whiplash trauma using whole cervical spine specimens.
STUDY DESIGN: Whiplash injuries were studied in an experiment using whole cervical spine specimen. OBJECTIVES: To develop a whiplash trauma model that uses a whole cervical spine specimen, and to show the feasibility and unique features of such a model. SUMMARY OF BACKGROUND DATA: Whiplash trauma has been simulated in biomechanical experiments using volunteers, whole body cadavers, animals, anthropometric dummies, and mathematic models. These experiments require large facilities, are expensive, and provide limited information about cervical spine injuries. METHODS: An alternate approach, in which a bench-top sled accelerating apparatus is used to produce whiplash trauma, has been developed to study such trauma in whole cervical spine specimens. Several transducers were developed to monitor soft tissue injuries during the trauma. The model also provides quantification of injuries to the cervical spine. RESULTS: To assess the feasibility and usefulness of the model, a specimen was traumatized, and the following parameters were monitored during the trauma: linear acceleration of the sled, linear and angular acceleration of the head surrogate, displacements of the head surrogate, loads at T1 and C1 vertebrae, and linear deformations of capsular ligaments and vertebral artery. CONCLUSIONS: This model, which incorporates a fresh cadaveric whole human cervical spine specimen, can simulate whiplash trauma effectively and is useful in providing a comprehensive set of clinically relevant information during the trauma. This model gives insight into the complex events and interactions that cause the injuries that occur during whiplash trauma.
Cadaver↗
[Biomechanics of whiplash injury].
The article reports a new hypothesis of whiplash injury based on a series of experimental studies using isolated human cadaveric specimens. Although the clinical symptoms of whiplash are widely known, the understanding of the underlying injury mechanism is poor. The prevailing view of neck-hyper-extension as the essential injury mechanisms was not supported by recent experiments. In a series of experiments using eight human cadaveric specimens which underwent experimental stepwise whiplash acceleration from 2.5 to 10.5 g functional radiographs and flexibility tests were performed at the end of each acceleration step. Ligament strains, vertebral alignment and elongation of the vertebral artery were monitored during the whiplash trauma by highspeed cinematography and specially designed transducers. After the trauma CT- and MRI-scans were taken and specimens were sectioned using Cryomicrotomy. We found a distinct biphasic kinematic response of the cervical spine to whiplash trauma. In the first phase the spine formed an S-shaped curve with flexion at the upper levels and hyper-extension at the lower levels. This phase was found to be the vulnerable phase of whiplash trauma. The largest dynamic elongation of the capsular ligaments was observed at the C6-C7 level during this initial S-shaped phase of whiplash. The maximum elongation of the vertebral artery could be observed synchronously in the first S-shaped curve of the cervical spine. In the second phase of whiplash all levels of the cervical spine were extended, so that the head reached is maximum extension. No injuries were observed in the second phase. We propose, based on our experimental findings, that with low accelerations the anterior structures of the lower cervical spine are injured during the first phase of whiplash, when the cervical spine forms an S-shaped curve and before the neck is fully extended. At higher trauma accelerations there is also a tendency for the injuries to occur at upper levels of the cervical spine. Based on our findings the traditional view of whiplash as hyper-extension injury can be modified by a differentiated, time dependent, biphasic biomechanical model of the injury, thus allowing better and more effective injury prevention, diagnosis and therapy.
Biomechanical Phenomena↗
Head kinematics during in vitro whiplash simulation.
Knowledge of precise head kinematics during whiplash trauma is important for identifying possible injury mechanisms and their prevention. This study reports a comprehensive data set describing head kinematic response to horizontal accelerations simulating whiplash. Seven isolated fresh human cervical spine specimens (C0 to T1 or C7), each carrying a surrogate head designed to represent a 50th percentile human head, were mounted on the sled and subjected to incremental trauma by horizontal sled accelerations of 2.5, 4.5, 6.5, 8.5, and 10.5 g. Sled and head kinematics were measured with potentiometers and accelerometers. The incremental sled accelerations resulted in average (standard deviations) sled velocity changes (delta V) ranging from 5.8 (0.2) to 15.8 (0.2) km/h. Generally, all the peak head kinematic parameters increased with increasing sled acceleration, except for the peak head angular displacement, which decreased. In the initial phase of a whiplash trauma, the head translated posteriorly with respect to T1, without rotation. In the later phase, the head rotated backwards, but much less than its physiological limit. Maximum head rotation of 31.5 (23.9) degrees occurred in a 2.5 g trauma class, and this was less than the maximum physiological head extension of 55.1 (13.3) degrees. Head kinematics expressed in the T1 or shoulder coordinate system is better suited to study potential neck injury in whiplash.
Accidents, Traffic↗
PET with 18fluorodeoxyglucose and hexamethylpropylene amine oxime SPECT in late whiplash syndrome.
BACKGROUND: Many patients have cognitive abnormalities and psychological problems after whiplash injury to the cervical spine. To our knowledge, neuroradiologic imaging has not depicted brain damage that explains the symptoms. Parietotemporo-occipital perfusion deficits on hexamethylpropylene amine oxime (HMPAO) SPECT studies have been described among patients who have sustained whiplash injury. METHODS: We examined 13 patients with typical late whiplash syndrome (study group) using HMPAO SPECT, 18fluorodeoxyglucose (FDG) PET, and MRI of the brain and compared the findings with those for 16 control subjects who underwent FDG PET. RESULTS: In the study group, statistical parametric mapping revealed significantly decreased FDG uptake in the frontopolar and lateral temporal cortex and in the putamen. The frontopolar hypometabolism correlated significantly with scores of the Beck Depression Inventory. However, in individual cases, reliability in the depiction of hypometabolic areas was relatively low. No alterations were found in the parietotemporo-occipital area. In these areas, decreased uptake of HMPAO and FDG correlated with cortical mass. CONCLUSION: FDG PET did not allow reliable diagnosis of metabolic disturbances for individual patients. Therefore, we do not recommend FDG PET or HMPAO SPECT as a diagnostic tool in routine examinations of patients with late whiplash syndrome.
Adult↗
Whiplash produces an S-shaped curvature of the neck with hyperextension at lower levels.
STUDY DESIGN: A bench-top trauma sled was used to apply four intensities of whiplash trauma to human cadaveric cervical spine specimens and to measure resulting intervertebral rotations using high-speed cinematography. OBJECTIVES: To determine the cervical spine levels most prone to injury from whiplash trauma and to hypothesize a mechanism for such injury. SUMMARY OF BACKGROUND DATA: Whiplash injuries traditionally have been ascribed to hyperextension of the head, but other mechanisms such as hypertranslation also have been suggested. METHODS: Six occiput to T1 (or C7) fresh cadaveric human spines were studied. Physiologic flexion and extension motions were recorded with an Optotrak motion analysis system by loading up to 1.0 Nm. Specimens then were secured in a trauma sled, and a surrogate head was attached. Flags fixed to the head and individual vertebrae were monitored with high-speed cinematography (500 frames/sec). Data were collected for 12 traumas in four classes defined by the maximum sled acceleration. The trauma classes were 2.5 g, 4.5 g, 6.5 g, and 8.5 g. Significance was defined at P < 0.01. RESULTS: In the whiplash traumas, the peak intervertebral rotations of C6-C7 and C7-T1 significantly exceeded the maximum physiologic extension for all trauma classes studied. The maximum extension of these lower levels occurred significantly before full neck extension. In fact, the upper cervical levels were consistently in flexion at the time of maximum lower level extension. CONCLUSIONS: In whiplash, the neck forms an S-shaped curvature, with lower level hyperextension and upper level flexion. This was identified as the injury stage for the lower cervical levels. A subsequent C-shaped curvature with extension of the entire cervical spine produced less lower level extension.
Biomechanical Phenomena↗
Atlantoaxial fusion and retrodental pannus in rheumatoid arthritis.
STUDY DESIGN: This study analyzed the influence of atlantoaxial fusion in rheumatoid arthritis patients on inflammatory retrodental pannus. OBJECTIVES: To determine the value of fusion on the magnitude of pannus as a compressive structure on the spinal cord. SUMMARY OF BACKGROUND DATA: Transverse and vertical instability may lead to neurologic deficits from spinal cord compression. Increased size of the retrodental pannus can exacerbate the neurologic deterioration. Anterior removal of dens and pannus followed by posterior fusion has been proposed in such situations as a method to relieve spinal cord compression. METHODS: Twenty-two patients with atlantoaxial instability and verified pannus on magnetic resonance imaging underwent posterior fusion of the upper cervical spine. These patients were followed 12 to 75 months after surgery by clinical, radiologic, and magnetic resonance imaging evaluations. The size of the pannus was compared before and after surgery. RESULTS: In all patients, the retrodental pannus had significantly decreased or disappeared postoperatively. CONCLUSIONS: Pannus reduction occurred even in patients whose disease was active or progressing, supporting the hypothesis that the pannus is more a reactive fibrous tissue resulting from instability rather than a direct consequence of the inflammatory process itself.
Adult↗
Fibre type characteristics of the lumbar paraspinal muscles in normal healthy subjects and in patients with low back pain.
A knowledge of the alteration in the fibre type profile of paraspinal muscle associated with low back pain is essential for the design of successful rehabilitation programmes. In attempting to compare the muscles of patients with low back pain with those of controls, few previous studies have considered factors such as gender, age, and size of the subjects, each of which can potentially confound interpretation of the results. We obtained samples of lumbar paraspinal muscle during spinal surgery from 21 patients with low back pain and, using the percutaneous biopsy technique, from 21 control volunteers matched for gender, age, and body mass. The samples were subject to routine histochemical analysis to determine characteristics of muscle fibre type. Compared with controls, the muscle of the patients had a significantly higher proportion of type-IIB (fast-twitch glycolytic) fibres than type-I (slow oxidative) fibres. The mean size of a given fibre type did not differ between the patients and the controls. Consequently, the relative area of the muscle occupied by type-IIB fibres was higher and that by type-I fibres was lower in the patients. The patients had a greater number of muscle samples with more than 1% type-IIC fibres, and abnormalities that could be described as pathological were more marked in the patients than in the controls. In conclusion, the paraspinal muscles of patients who have low back pain display a more glycolytic (faster) profile; this can be expected to render them less resistant to fatigue.
Adenosine Triphosphatases↗
Dynamic elongation of the vertebral artery during an in vitro whiplash simulation.
Clinical signs of whiplash are presently not well understood. Vertebral artery (VA) stretch during trauma is a possible pathomechanism that could explain some aspects of the whiplash symptom complex. This study quantified the VA elongation during whiplash simulation using an in vitro model. Seven fresh human cadaveric specimens (occiput to C7 or T1) were carefully dissected, preserving the osteoligamentous structures. The right VA was replaced with a thin nylon-coated flexible cable. This cable was fixed at one end to the occipital bone and at the other end to a specially designed VA transducer. Physiological motion of the occiput and physiological elongation of the VA were measured with a standard flexibility test. Next the specimen was mounted on a specially designed sled and subjected to 2.5, 4.5, 6.5, and 8.5 g (1 g = 9.81 m/s2) horizontal accelerations. Elongation of the VA was continuously recorded from the start of the trauma. The average (standard deviation) physiological VA elongation was 5.8 (1.6) mm in left lateral bending and 4.7 (1.8) mm in left axial rotation. Flexion and extension did not result in any appreciable elongation of the VA. The maximum VA elongation during the whiplash trauma significantly correlated with the horizontal acceleration of the sled (R2 = 0.7, P < 0.05). The VA exceeded its physiological range by 1.0 (2.1), 3.1 (2.6), 8.9 (1.6), and 9.0 (5.9) mm in the 2.5-, 4.5-, 6.5-, and 8.5-g trauma classes respectively.
Biomechanical Phenomena↗
[Headache in cervical syndrome].
Headache is a common symptom in patients suffering from cervical spine disorders. The percentage of headaches in association with degenerative changes of the cervical spine ranges from 13 to 79% and that in association with indirect trauma of the cervical spine from 48 to 82%. Based on neuroanatomical and neurophysiological studies, the relationship of the upper cervical spine and the trigeminal nuclei has been demonstrated and serves as an explanation for perceived head pain in cervical spine disorders. As a source of pain, tension in the suboccipital muscles, irritation of the third occipital nerve, and degenerative changes of the C2/C3 joints have been discussed. Bogduk, in his studies, asserts a direct causative role of mechanical derangement of the cervical spine in the pathogenesis of cervicogenic headaches. In 1983, Sjaastad et al. postulated the concept of 'cervicogenic headaches': a migraine-like headache due to certain disorders of the cervical spine, strictly located unilaterally, its manifestations being in the temporal, frontal, and ocular areas, with associated symptoms such as slight lacrimation, conjunctival injections, tinnitus, runny nose, and erythema in the forehead ipsilaterally. As arguments in favour of a cervical origin, Sjaastad mentioned the following features: precipitation of the headaches either by neck movements or by pressure against certain tender spots on the neck, the possibility of homolateral shoulder or arm pain, stiffness and pain of the neck, and reduced mobility of the cervical spine. In 1988, the Headache Classification Committee of the International Headache Society set strict criteria for 'headaches' to be classified as to be of cervical origin.
Cervical Vertebrae↗