Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SPINE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

Biomechanical evaluation of methods of posterior stabilization of the spine and posterior lumbar interbody arthrodesis for lumbosacral isthmic spondylolisthesis. A calf-spine model.

In order to evaluate biomechanically the efficacy of four types of posterior instrumentation for the stabilization of isthmic spondylolisthesis of the lumbosacral spine, mechanical non-destructive cyclic testing in axial compression, flexion, extension, and rotation was performed on six fresh lumbosacral spines from calves. Each segment contained four motion segments, including the lumbosacral junction. Isthmic spondylolisthesis was created by sectioning the pars interarticularis of the sixth lumbar vertebra and all posterior ligaments between the fifth and sixth lumbar levels. Eight constructs were tested sequentially: (1) the intact spine, (2) the destabilized spine, (3) the spine fixed with Harrington double-distraction rods, (4) the spine treated with transpedicular Cotrel-Dubousset instrumentation with a transverse approximating device, (5) the spine treated with Steffee transpedicular screws and plates, (6) the spine treated with posterior lumbar interbody arthrodesis, (7) the spine treated with Cotrel-Dubousset instrumentation and posterior lumbar interbody arthrodesis, and (8) the spine treated with Steffee instrumentation and posterior lumbar interbody arthrodesis. One motion segment was involved in each construct, except for the spine that was fixed with Harrington instrumentation, which involved three segments. Strain across the supraspinous and anterior longitudinal ligaments was measured with two extensometers that were attached at the spondylolisthetic level and at the intact motion segments adjacent to the fixed level. Harrington instrumentation was the least rigid construct under any type of loading except axial compression (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Kinematics of the scoliotic spine as related to the normal spine.

A coupling between the lateral flexion and axial rotation as a result of the geometric arrangement of the motion segments is well known in a normal spine. The kinematic behavior of idiopathic scoliotic spines has been analyzed by means of a biomechanical model study and a radiologic study. The anteroposterior and lateral flexion radiographs of 40 patients with progressive adolescent idiopathic scoliosis were studied. In five of these patients, anteroposterior radiographs were also made with the spine in a ventrally flexed position. The kinematic behavior of a nonpathologic spine was examined by means of a three-dimensional, nonlinear geometric mathematical model of the spine. The frontal plane inclination of the facet joints in conjunction with the vertebral orientation in the sagittal plane influence the kinematic behavior in the normal spine. In a scoliotic spine, there is an axially rotated position and, in most cases, a dorsal inclination (lordotic) of the motion segments. Nevertheless, the direction of the axial rotation during lateral flexion does not differ from the direction of the axial rotation during lateral flexion in a normal spine. The existing axial rotation in idiopathic scoliosis cannot be explained on the basis of spinal kinematics. In contrast to normal spines, in scoliotic spines exists a coupling between ventral flexion or extension and axial rotation. This may be essential in the management of idiopathic scoliosis.

Adolescent↗

Calcium dynamics in dendritic spines and spine motility.

A dendritic spine is an intracellular compartment in synapses of central neurons. The role of the fast twitching of spines, brought about by a transient rise of internal calcium concentration above that of the parent dendrite, has been hitherto unclear. We propose an explanation of the cause and effect of the twitching and its role in the functioning of the spine as a fast calcium compartment. Our molecular model postulates that rapid spine motility is due to the concerted contraction of calcium-binding proteins. The contraction induces a stream of cytoplasmic fluid in the direction of the dendritic shaft, thus speeding up the time course of spine calcium dynamics, relative to pure diffusion. Simulations indicate that chemical reaction rate theory at the molecular level can explain spine motility. They reveal two time periods in calcium dynamics, as measured recently by other researchers. It appears that rapid motility in dendritic spines increases the efficiency of calcium conduction to the dendrite and speeds up the emptying of the spine. This could play a major role in the induction of synaptic plasticity. A prediction of the model is that alteration of spine motility will modify the time course of calcium in the dendritic spine and could be tested experimentally.

Animals↗

Local communication within dendritic spines: models of second messenger diffusion in granule cell spines of the mammalian olfactory bulb.

Dendritic spines are generally believed to play a role in modulating synaptically induced electrical events. In addition, they may also confine second messengers and thus topologically limit the distance over which second messenger cascades may be functionally significant. In order to address this possibility, computer simulations of transient second messenger concentration changes were performed. The results show the importance of spine morphology and binding and extrusion mechanisms in controlling second messenger transients. In the presence of intrinsic cytoplasmic binding sites and kinetic rates similar to that expected for calcium, second messengers were confined to the spine head. In the absence of binding/extrusion mechanisms, the size and time course of the input transient to the spine head influenced the second messenger transients that might be seen at the base of the spine neck and in other spines. Large and/or sustained increases in second messenger concentration in the spine head were communicated to the spine base and to other spine heads. The results emphasize the importance of a knowledge of breakdown pathways, concentrations and kinetics of binding sites, and extrusion mechanisms for understanding the dynamics of local chemical changes for dendritic spine function.

Animals↗

Regulation of spine calcium dynamics by rapid spine motility.

Dendritic spines receive most excitatory inputs in the CNS and compartmentalize calcium. Spines also undergo rapid morphological changes, although the function of this motility is still unclear. We have investigated the effect of spine movement on spine calcium dynamics with two-photon photobleaching of enhanced green fluorescent protein and calcium imaging of action potential-elicited transients in spines from layer 2/3 pyramidal neurons in mouse visual cortex slices. The elongation or retraction of the spine neck during spine motility alters the diffusional coupling between spine and dendrite and significantly changes calcium decay kinetics in spines. Our results demonstrate that the spine's ability to compartmentalize calcium is constantly changing.

Acoustic Stimulation↗

Influence of spine morphology on intervertebral disc loads and stresses in asymptomatic adults: implications for the ideal spine.

BACKGROUND CONTEXT: Sagittal profiles of the spine have been hypothesized to influence spinal coupling and loads on spinal tissues. PURPOSE: To assess the relationship between thoracolumbar spine sagittal morphology and intervertebral disc loads and stresses. STUDY DESIGN: A cross-sectional study evaluating sagittal X-ray geometry and postural loading in asymptomatic men and women. PATIENT SAMPLE: Sixty-seven young and asymptomatic subjects (chiropractic students) formed the study group. OUTCOME MEASURES: Morphological data derived from radiographs (anatomic angles and sagittal balance parameters) and biomechanical parameters (intervertebral disc loads and stresses) derived from a postural loading model. METHODS: An anatomically accurate, sagittal plane, upright posture, quadrilateral element model of the anterior spinal column (C2-S1) was created by digitizing lateral full-spine X-rays of 67 human subjects (51 males, 16 females). Morphological measurements of sagittal curvature and balance were compared with intervertebral disc loads and stresses obtained using a quadrilateral element postural loading model. RESULTS: In this young (mean 26.7, SD 4.8 years), asymptomatic male and female population, the neutral posture spine was characterized by an average thoracic angle (T1-T12) = +43.7 degrees (SD 11.4 degrees ), lumbar angle (T12-S1) = -63.2 degrees (SD 10.0 degrees ), and pelvic angle = +49.4 degrees (SD 9.9 degrees ). Sagittal curvatures exhibited relatively broad frequency distributions, with the pelvic angle showing the least variance and the thoracic angle showing the greatest variance. Sagittal balance parameters, C7-S1 and T1-T12, showed the best average vertical alignment (5.3 mm and -0.04 mm, respectively). Anterior and posterior disc postural loads were balanced at T8-T9 and showed the greatest difference at L5-S1. Disc compressive stresses were greatest in the mid-thoracic region of the spine, whereas shear stresses were highest at L5-S1. Significant linear correlations (p < .001) were found between a number of biomechanical and morphological parameters. Notably, thoracic shear stresses and compressive stresses were correlated to T1-T12 and T4-hip axis (HA) sagittal balance, respectively, but not to sagittal angles. Lumbar shear stresses and body weight (BW) normalized shear loads were correlated with T12-S1 balance, lumbar angle, and sacral angle. BW normalized lumbar compressive loads were correlated with T12-S1 balance and sacral angle. BW normalized lumbar disc shear (compressive) loads increased (decreased) significantly with decreasing lumbar lordosis. Cervical compressive stresses and loads were correlated with all sagittal balance parameters except S1-HA and T12-S1. A neutral spine sagittal model was constructed from the 67 subjects. CONCLUSIONS: The analyses suggest that sagittal spine balance and curvature are important parameters for postural load balance in healthy male and female subjects. Morphological predictors of altered disc load outcomes were sagittal balance parameters in the thoracic spine and anatomic angles in the lumbar spine.

Adult↗

Dynamics of dendritic spines and their afferent terminals: spines are more motile than presynaptic boutons.

Previous work has established that dendritic spines, sites of excitatory input in CNS neurons, can be highly dynamic, in later development as well as in mature brain. Although spine motility has been proposed to facilitate the formation of new synaptic contacts, we have reported that spines continue to be dynamic even if they bear synaptic contacts. An outstanding question related to this finding is whether the presynaptic terminals that contact dendritic spines are as dynamic as their postsynaptic targets. Using multiphoton time-lapse microscopy of GFP-labeled Purkinje cells and DiI-labeled granule cell parallel fiber afferents in cerebellar slices, we monitored the dynamic behavior of both presynaptic terminals and postsynaptic dendritic spines in the same preparation. We report that while spines are dynamic, the presynaptic terminals they contact are quite stable. We confirmed the relatively low levels of presynaptic terminal motility by imaging parallel fibers in vivo. Finally, spine motility can occur when a functional presynaptic terminal is apposed to it. These analyses further call into question the function of spine motility, and to what extent the synapse breaks or maintains its contact during the movement of the spine.

Animals↗

Trabecular bone structure of the distal radius, the calcaneus, and the spine: which site predicts fracture status of the spine best?

RATIONALE AND OBJECTIVES: To compare trabecular bone structure measures obtained in magnetic resonance images of the distal radius and the calcaneus as well as computed tomographic images of the spine versus bone mineral density (BMD) of the spine and the calcaneus in the prediction of osteoporotic spine fracture status. MATERIAL AND METHODS: High-resolution magnetic resonance images of the calcaneus and the distal radius and thin-section computed tomographic images of thoracic and lumbar vertebrae were obtained from 74 cadavers. Structure analysis was performed using parameters analogous to standard histomorphometry. BMD of the spine was determined by using quantitative computed tomography and of the calcaneus by using dual x-ray absorptiometry. Spine radiographs of these cadavers were assessed concerning vertebral deformities. RESULTS: The diagnostic performance in differentiating fracture and nonfracture subjects was highest for structure parameters in the spine and slightly lower for these parameters in the distal radius and for BMD of the spine. CONCLUSION: In this study structure parameters in the spine were best suited to predict the osteoporotic fracture status of the spine.

Absorptiometry, Photon↗

A comparison of fear-avoidance beliefs in patients with lumbar spine pain and cervical spine pain.

STUDY DESIGN: A prospective consecutive cohort study of patients with cervical spine pain and patients with lumbar spine pain referred to an academic medical center. OBJECTIVES: To investigate the presence of fear-avoidance beliefs in a sample of patients with cervical spine pain and to compare the association of pain intensity, disability, and fear-avoidance beliefs in patients with cervical spine pain with that in patients with lumbar spine pain. SUMMARY OF BACKGROUND DATA: Fear-avoidance beliefs are a specific psychosocial variable involved in the development of disability from low back pain. Psychosocial variables are believed to play a role in cervical disability, but specific variables have not been investigated. METHODS: Consecutive patients referred to a multidisciplinary center completed self-reports of disability, pain intensity, and fear-avoidance beliefs during an initial evaluation session. Gender, type of symptom onset, acuity, and payer source were also recorded. Associations between disability, pain intensity, and fear-avoidance beliefs were investigated in patients with cervical spine pain and patients with lumbar spine pain. RESULTS: In all, 163 patients completed the self-reports and were included in this study. Weaker relations between fear-avoidance beliefs and disability were found in patients with cervical pain than in those with lumbar pain. Significant differences in fear-avoidance beliefs were found for gender, type of symptom onset, and payer source (workers' compensation, auto insurance, and traditional insurance). CONCLUSION: The associations among fear-avoidance beliefs, pain intensity, and disability differed between patients with cervical spine pain and patients with lumbar spine pain. Fear-avoidance beliefs were significantly different in subgroups of patients.

Adult↗

Bedside fluoroscopic flexion and extension cervical spine radiographs for clearance of the cervical spine in comatose trauma patients.

BACKGROUND: Bedside flexion and extension fluoroscopic examinations have been proposed as an option for clearance of the cervical spine in comatose brain-injured patients. We hypothesized that these studies, when performed after normal static imaging of the cervical spine, would have an extremely low likelihood of identifying occult ligamentous instability and would not be adequate for visualizing the lower cervical spine. METHODS: Radiographic images obtained from 56 consecutive comatose head-injured patients were reviewed. All patients had normal anteroposterior, lateral, and open mouth odontoid cervical spine radiographs and normal thin-cut axial computed tomographic images from the occiput to C2 and through the lower cervical spine if suspicious areas were identified on plain cervical spine radiographs. After these static images were determined to be normal by both the attending neurosurgeon and the attending radiologist, all 56 patients had bedside fluoroscopic flexion and extension studies performed by the neurosurgery resident, with the patients' arms being pulled down to their sides by the primary care nurse. RESULTS: The bedside fluoroscopic flexion and extension studies were considered to be adequate (visualization to the C7-T1 motion segment) in only 4% of the patients. Occult instability was identified in one patient (type II odontoid fracture) and significant instability was missed in one patient with C6 to C7 dislocation in whom flexion and extension radiographs failed to visualize the C6 to C7 motion segment. CONCLUSION: Bedside flexion and extension fluoroscopy was almost always inadequate for visualizing the lower cervical spine in comatose head-injured patients. Because of the extremely low likelihood of visualizing the entire cervical spine with this technique, we recommend that it no longer be considered an option in trauma center protocols for clearance of the cervical spine in comatose brain-injured patients.

Adult↗

Reduction in spine density associated with long-term potentiation in the dentate gyrus suggests a spine fusion-and-branching model of potentiation.

Approximately 2,700 dendritic spines in Golgi-impregnated hippocampal granule cells were quantified via image analysis 24 h after the unilateral induction of long-term potentiation in seven rats. Stereological corrections were made using a tilting disector and analytical unfolding technique. In the potentiated hemisphere the mean spine density along dendrites was reduced by approximately 20%. The relative frequency of shorter, thicker spines was increased in potentiated tissue. Physiological consequences of two morphological changes leading to a reduction in spine density (retraction or fusion of spines) were examined using a compartmental model of a simplified granule cell. The model was constructed in the NEURON modeling environment and included a realistic population of 60 dendritic spines (with dual-component synapses and active Ca(2+)-dependent mechanisms). Simulations demonstrated that potentiation of postsynaptic responses was compatible with fusion (with branching) of a proportion of spines with their neighbors but was not compatible with retraction of spines. This result held over wide variations of model parameters as long as dendritic membranes were assumed to be excitable.

Animals↗

Comparative study of the olfactory epithelium of the three-spined stickleback (Gasterosteus aculeatus) and the nine-spined stickleback (Pungitius pungitius).

The olfactory epithelium of the three-spined stickleback (Gasterosteus aculeatus) and the nine-spined stickleback (Pungitius pungitius) has been studied with a conventional histochemical and a novel immunological staining technique. In both species, the sensory epithelium is arranged in folds separated by non-sensory epithelial tissue. In the nine-spined stickleback, intrinsic folds consisting of non-sensory cells are found in the apical part of the sensory epithelium where they divide the surface of the sensory epithelium into small islets. These non-sensory cells are non-ciliated, flattened and piled on top of each other; they contain numerous electron-translucent vesicles. The intrinsic folds are absent from the sensory epithelium of the three-spined stickleback. In both species, axons of receptor cells form a layer of fibers in the sensory epithelium immediately above the basal cells. In the three-spined stickleback, thick branches of the olfactory nerve are frequently found in this layer. These branches are only occasionally observed in the sensory epithelium of the nine-spined stickleback. Thus, the three-spined stickleback and the nine-spined stickleback show considerable differences in the organization of the sensory regions of the olfactory epithelium.

Animals↗

A longitudinal study of supine lateral DXA of the lumbar spine: a comparison with posteroanterior spine, hip and total-body DXA.

We report a study to assess whether supine lateral dual-energy X-ray absorptiometry (DXA) scans of the lumbar spine provide better data for monitoring response to treatment than alternative measurement sites such as the posteroanterior (PA) spine, hip and total body. The study population was 152 women enrolled in a placebo-controlled clinical trial of cyclical etidronate therapy. All subjects were 1-10 years after the menopause with bone mineral density (BMD) between 0 and -2 SD of age-matched normal women. Paired PA and lateral spine, left hip and total-body DXA scans were performed at baseline, 1 year and 2 years on a Hologic QDR-2000. One hundred and thirty-one subjects completed the study. Mean percentage change from baseline at 2 years in the treated (n = 61) and control (n = 70) groups was calculated for vertebral body, width-adjusted (WA) vertebral body, mid-vertebral body and WA mid-vertebral body BMD measurement on the lateral scans and compared with the percentage changes in PA spine, femoral neck, trochanter, Ward's triangle and total-body BMD. The long-term precision for each BMD measurement site was obtained by linear regression analysis in subjects taking placebo. Overall treatment effect, defined as the difference in the percentage change in BMD in the two treatment groups at 2 years, was divided by long-term precision to give an index of the ability of each site to monitor response to treatment. Results (and standard errors) normalized to the ratio of treatment effect/ precision for PA spine BMD were as follows: PA spine, 1.00; vertebral body, 0.89 (0.14); WA vertebral body, 0.78 (0.14); mid-vertebral body, 0.65 (0.14); WA mid-vertebral body, 0.60 (0.13); femoral neck, 0.35 (0.15); trochanter, 0.45 (0.15); Ward's triangle, 0.59 (0.22); total body, 0.52 (0.19). Although treatment effect was larger for lateral than for PA spine BMD, this advantage was offset by the greater precision errors. PA spine BMD remains the optimum measurement for longitudinal studies in recently postmenopausal women.

Absorptiometry, Photon↗

The use of radiological guidelines to achieve a sustained reduction in the number of radiographic examinations of the cervical spine, lumbar spine and knees performed for GPs.

AIM: To determine if the use of request guidelines can achieve a sustained reduction in the number of radiographic examinations of the cervical spine, lumbar spine and knee joints performed for general practitioners (GPs). METHODS: GPs referring to three community hospitals and a district general hospital were circulated with referral guidelines for radiography of the cervical spine, lumbar spine and knee, and all requests for these three examinations were checked. Requests that did not fit the guidelines were returned to the GP with an explanatory letter and a further copy of the guidelines. Where applicable, a large-joint replacement algorithm was also enclosed. If the GP maintained the opinion that the examination was indicated, she or he had the option of supplying further justifying information in writing or speaking to a consultant radiologist. RESULTS: Overall the number of radiographic examinations fell by 68% in the first year, achieving a 79% reduction in the second year. For knees, lumbar spine and cervical spine radiographs the total reductions were 77%, 78% and 86%, respectively. CONCLUSION: The use of referral guidelines, reinforced by request checking and clinical management algorithms, can produce a dramatic and sustained reduction in the number of radiographs of the cervical spine, lumbar spine and knees performed for GPs.

Algorithms↗

The treatment of spine and chest wall deformities with fused ribs by expansion thoracostomy and insertion of vertical expandable prosthetic titanium rib: growth of thoracic spine and improvement of lung volumes.

STUDY DESIGN: Prospective clinical trial of vertical expandable prosthetic titanium rib (VEPTR) in patients with combined spine and chest wall deformity with scoliosis and fused ribs. OBJECTIVE: Report the efficacy and safety of expansion thoracostomy and VEPTR surgery in the treatment of thoracic insufficiency syndrome (TIS) associated with fused ribs. SUMMARY OF BACKGROUND DATA: Traditional attitudes toward early-onset combined chest and spine deformity assume that thoracic deformity is best controlled by treatment directed at spine deformity, often involving early spinal arthrodesis. Campbell and others have heightened awareness of the interrelationship between lung, chest, and spine development during growth and characterized TIS as the inability of the thorax to support normal respiration or lung growth. Expansion thoracostomy and VEPTR insertion was developed to directly control both spine and chest wall deformity during growth, while permitting continued vertebral column and chest growth at an early stage. METHODS: Multidisciplinary evaluation of children with combined spine and chest wall deformity included pediatric pulmonologist, thoracic, and orthopedic surgeon evaluations. One or more opening wedge expansion thoracostomies and placement of VEPTR devices were performed as described by Campbell, with repeated device lengthenings during growth. Parameters measured included Cobb angle, length of thoracic spine, CT-derived lung volumes, and in older children pulmonary function tests. RESULTS: Thirty-one patients with fused ribs and TIS were treated, 4 of whom had undergone prior spinal arthrodesis at other institutions with continued progression of deformity. In 30 patients, the spinal deformity was controlled and growth continued in the thoracic spine during treatment at rates similar to normals. Increased volume of the constricted hemithorax and total lung volumes obtained during expansion thoracostomy were maintained at follow-up. Complications included device migration, infection, and brachial plexus palsy. CONCLUSIONS: Expansion thoracostomy and VEPTR insertion with serial lengthening may be the preferred treatment for young children with chest wall deformity and scoliosis associated with fused ribs but requires multidisciplinary care and attention to details of soft tissue management. When indicated, surgical intervention with VEPTR can be considered early in growth, before deformity is severe, since spinal growth will continue with treatment.

Abnormalities, Multiple↗

Padded vs unpadded spine board for cervical spine immobilization.

OBJECTIVES: To determine whether padding the long spine board improves patient comfort, affects cervical spine (c-spine) immobilization, or increases sacral transcutaneous O2 tension. METHODS: A prospective randomized, controlled crossover study of healthy volunteers was conducted over a two-week period. Participants included 30 volunteers with no previous history of c-spine injury or disease. The subjects were randomized to either padded or unpadded long spine board immobilization with serial measurements of discomfort (using a visual analog scale) and transcutaneous tissue O2 tension obtained at zero and 30 minutes. Measurements of ability to flex, extend, rotate, and laterally bend the c-spine were made using a goniometer. The subjects then returned a minimum of three days later to complete the opposite half of the study (padded vs unpadded boards). RESULTS: Subject discomfort was significantly reduced in the padded group compared with the unpadded group (p = 0.024). There was no significant difference in flexion (p = 0.410), extension (p = 0.231), rotation (p = 0.891), or lateral bending (p = 0.230) for the two groups. There was no significant difference in the actual drop in sacral transcutaneous O2 tension from time zero to 30 minutes for the padded and the unpadded groups (mean drop = 14.8% +/- 17.5% vs 12.2% +/- 16.8%, respectively; p = 0.906). CONCLUSION: Adding closed-cell foam padding to a long spine board significantly improves comfort without compromising c-spine immobilization. Sacral tissue oxygenation does not appear affected by such padding for healthy volunteers.

Adult↗

Spear tackler's spine. An entity precluding participation in tackle football and collision activities that expose the cervical spine to axial energy inputs.

We describe spear tackler's spine, a clinical entity that constitutes an absolute contraindication to participation in tackle football and other collision activities that expose the cervical spine to axial energy inputs. A subset of football players were identified who demonstrated: 1) developmental narrowing (stenosis) of the cervical canal; 2) persistent straightening or reversal of the normal cervical lordotic curve on erect lateral roentgenograms obtained in the neutral position; 3) concomitant preexisting posttraumatic roentgenographic abnormalities of the cervical spine; and 4) documentation of having employed spear tackling techniques. From data obtained by the National Football Head and Neck Injury Registry and the senior author's practice, 15 cases of spear tackler's spine were identified during 1987 to 1990. All 15 cases were evaluated because of complaints referable to the cervical spine or brachial plexus resulting from football injuries. Of these, 11 had complete neurologic recovery without permanent sequelae. Four cases resulted in permanent neurologic deficits: quadriplegia, 2; incomplete hemiplegia, 1; and residual long track signs, 1. Permanent neurologic injury occurred as the result of axial loading of a persistently straightened cervical spine from use of head-impact playing techniques. We suggest that individuals who possess the aforementioned characteristics of spear tackler's spine be precluded from participation in collision activities that expose the cervical spine to axial energy inputs.

Adolescent↗

Rigid spine syndrome and rigid spine sign in myopathies.

We studied eight patients with rigid spine syndrome aged 8 to 20 years at the time of first examination. Muscle weakness, rigid spine, and flexion contracture of elbows and ankles were noted in the first 6 years of age. Radiological study of the cervical spine revealed considerable reduction not only of flexion, but also of extension, of the neck. The "alligator sign" was demonstrated. Progression of scoliosis and of contractures reduced the functional capacity in six patients. A restrictive ventilatory syndrome was observed in all, while central apneas with oxygen desaturation were shown in two. Cardiac arrhythmias were observed in four. We suggest that a distinction should be made between myopathic rigid spine and rigid spine syndrome. Myopathic rigid spine is a clinical sign which is rarely sought but is present in several types of well-defined myopathies, meaning the myopathic involvement of the extensor muscles of the spine. Rigid spine syndrome is an axial myopathy with peculiar clinical and radiographic signs and a characteristic natural history.

Adolescent↗