摘要:

Study DesignThe superficial and deep lamina of the posterior layer of the thoracolumbar fascia have been studied anatomically and biomechanically. In embalmed human specimens, the posterior layer has been loaded by simulating the action of various muscles. The effect has been studied using raster photography.ObjectivesTo study the role of the posterior layer of the thoracolumbar fascia in load transfer between spine, pelvis, legs, and arms.Summary of Background DataIt has been determined whether muscles such as the gluteus maximus, latissimus dorsi, erector muscle, and biceps femoris are functionally coupled via the thoracolumbar fascia. The caudal relations of the posterior layer of the thoracolumbar fascia have not been previously studied.MethodsDissection was directed to the bilaminar posterior layer of the thoracolumbar fascia of 10 human specimens. The superficial and deep lamina were studied using visual inspection and raster photography. Tension to the posterior layer of the fascia was simulated by traction to various muscles and measured by studying the displacement in the posterior layer.ResultsTraction to a variety of muscles caused displacement of the posterior layer. This implies thatin vivo, the superficial lamina will be tensed by contraction of various muscles, such as the latissimus dorsi, gluteus maximus and erector muscle, and the deep lamina by contraction of the biceps femoris. Caudal to the level of L4 (in some specimens, L2-L3), tension in the posterior layer was transmitted to the contralateral side.ConclusionsAnatomic structures normally described as hip, pelvic, and leg muscles interact with socalled arm and spinal muscles via the thoracolumbar fascia. This allows for effective load transfer between spine, pelvis, legs, and arms-an integrated system. Specific electromyographic studies should reveal whether the gluteus maximus muscle and contralateral latissimus dorsi muscle are functionally coupled, especially during rotation of the trunk. In that case, the combined action of these muscles assists in rotating the trunk, while simultaneously stabilizing the lower lumbar spine and sacroiliac joints.

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Study DesignThis study analyzed the vascular and skeletal anatomy of the sheep cervical spine. It discusses the comparative anatomy of the cervical spine of sheep and humans.ObjectivesTo establish the suitability of the sheep model for studying the pathophysiology of traumatic and degenerative conditions of the cervical spine.Summary of Background DataMany studies have attempted to evaluate the pathophysiology of spinal cord trauma, hypoxia, and variations in the local environment of the spinal cord using a variety of animal models. Few of the studies identified in an extensive literature review report or comment on the validity of these models regarding anatomy.MethodsTechniques of macro- and micro-dissection and vascular casting with latex and methyl-methacrylate were employed and the anatomy of sheep was compared with that of humans.ResultsOn an anatomical basis, we found the sheep to be a suitable model for studying the pathophysiology of spinal cord trauma and disorders relative to humans.ConclusionsTo properly assess the effect of various pathological processes on the spinal cord, an anatomically valid model is required. This study established that the sheep is a suitable animal model for studies of this type.

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Study DesignThis study retrospectively reviewed the clinical and radiographic results of a series of patients who underwent osteophyte resection during anterior discectomy and fusion.ObjectiveTo determine whether resection of the posterior uncinate process at the time of anterior cervical discectomy is safe and effective.Summary of Background DataPrevious studies have described techniques of osteophyte resection, but safety and outcome have not been supported by a clinical series of patients.MethodsForty-three consecutive patients with radiculopathy due to spondylosis or lateral herniated nucleus pulposus had 68 foraminotomies done at the time of anterior cervical disc foraminotomy for radiculopathy. All patients were followed-up until radiographic union. All patients were examined, and Odom's criteria were used to assess postoperative pain and function in the neck, arm, and iliac donor site.ResultsThe results were consistent with previous reports of anterior cervical disc foraminotomy for radiculopathy. Excellent and good results occurred in 77% and 14% of the patients, respectively. Three patients had no relief and no patient had worsening of radiculopathy. The fusion rate was 93%. Thirty-one patients (72%) reported being very satisfied. Three patients required a re-operation–one for bone graft dislodgment and two for pseudoarthrosis. No vascular injuries occurred.ConclusionsResection of the posterior portion of the uncinate process to remove osteophytes that narrow the neural foramen or to allow direct visualization of laterally herniated disc material can be done safely. When combined with an autogenous interbody bone graft, good results can be expected.

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Study DesignThis study analyzed the effects of distraction via strut graft insertion on the canal dimensions in spondylotic human cadaver cervical spines. Transverse and anteroposterior diameters and crosssectional areas were measured by transverse computed tomography imaging before and after distraction with out direct decompression.ObjectivesThis experiment was designed to address whether distraction across the disc space without direct canal decompression can improve the space available for the cord.Summary of Background DataSmith-Robinson anterior discectomy and fusion have been shown to improve clinical symptoms of radiculopathy and myelopthy even in the absence of direct decompression. This has been postulated to be the result of gradual resorption of intruding osteophytes. However, the immediate effects of indirect distraction alone have not been previously investigated.MethodsFour cadaver spines from elderly donors were harvested intact. The transverse diameter, anteroposterior diameter, and cross-sectional area of the spinal canal were measured before and after discectomy and distraction via insertion of fibular strut graft by digitization of contiguous computed tomography scan slices.ResultsThe spinal canal dimensions before distraction were found to vary in a sinusoidal pattern around the disc space, with the maximum measurements located at the pedicle and the minimum measurements at the spondylotic ridge above or below the disc space. Distraction via strut graft insertion significantly increased the anteroposterior diameter and cross-section area, but had a negligible effect on transverse diameter.ConclusionsAnterior discectomy and distraction with a strut graft can significantly improve the space available for the cord in cervical spondylosis. Osteophyte debridement, which risks latrogenic injury to the cord may not always be necessary for improving clinical radiculopathy and myelopathy.

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Study DesignA retrospective survey of the incidence of positive scoliosis screenings in schools for the hearing imparied was performed.ObjectivesThe incidence rate of scoliosis in a population with a high incidence of vestibular dysfunction was compared with the national normative incidence rate. The comparison was done to investigate the contribution of the vestibular system to scoliosis.Summary of Background DataSeveral reports have emphasized a possible neural etiology to idiopathic scoliosis. Based on the experimental hypothesis that an altered vestibular processing is critical for the production of scoliosis, 100 schools for the hearing impaired were surveyed to determine their incidence of postive screenings for scoliosis. Because it is known that hearing-imparied children have a high incidence of vestibular dysfunction, it was hypothesized that their screening incidence would change if the vestibular system contrbuted to idiopathic scoliosis.MethodsSurveys were sent to 100 schools for the hearing imparied asking for their most recent scoliosis screening data.ResultsOf the 40 surveys returned, 28 schools for the hearing imparied conducted routine scoliosis screenings, of which 17 had demographics representative of the national norms. Of the 3127 students screened at these 17 schools, 1.2% of the students screened positive for scoliosis. This is significantly less than national incidence rate of 4%-10%.Conclusion.The results suggested that hearin-impaired students may be a population that is protected from idiopathic scoliosis by a neural dysfunction. These data strongly suggest that idiopathic scoliosis has a neural etiology.

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Study DesignThe authors have developed technique of using anterior neck derivations to record posterior tibial nerve N28 during operative somatosensory-evoked potential monitoring.ObjectiveThis prospective study of 10 patients compared the ease of application of electrodes and stability of waveforms with “traditional” posterior neck recordings.Summary of Background DataSomatosensory-evoked potential monitoring has been used in children since the 1980s. A number of important factors, patient related and technical, are unique to this age group, which can cause difficulty with execution and interpretation. A major patient-related problem is unreliability of the cortical response in somatosensory-evoked potential monitoring because of the effect of inhalation anesthesia. This has been described as occurring more often in the pediatric group, perhaps because of the continuing maturation of the complex somatosensory system. Thus, the authors have relied heavily on the cervical potential to monitor spinal cord integrity. Recording the cervical response using the traditional “posterior” montage may be technically impossible if the electrodes lie within the operative field.MethodsPosterior tibial somatosensory-evoked potentials were performed according to the guidelines of the American Electroencephalographic Society. Additional recordings were obtained from two anterior neck sites. Multiple reference electrodes were used to evaluate which montage rendered the most reliable wave-form.ResultsOptimal montage for recording an anterior neck potential was cricoid cartilage-Cz'. There were no significant differences in the onset latency or peak amplitudes between the anterior and posterior cervical recordings.ConclusionsThe anterior neck derivation was found to be an acceptable adjunct to posterior montages, being stable, of comparable latency, and of stable amplitude. Electrodes are easier to apply, less invasive than nasopharyngeal or esophageal electrodes. This technique allows one to examine patients who previously could not be monitored.

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Study DesignThis was a survey of 235 individuals with and 132 individuals without documented low back pain.ObjectivesTo approximate the magnitude of potential reporting biases in estimates of prevalence of and medical care use in low back pain.Summary of Background DataThe use of survey techniques presents several possible biases in the reporting of acute symptoms. These biases are especially pertinent in musculoskeletal symptoms, which often are recurrent and not life-threatening.MethodsTwo-hundred-thirty-five patients with acute low back pain were contacted by telephone 4–16 months after their physician visit and surveyed regarding the presence and date of back pain episodes. One -hundred-thirty-two patients who had no functionally disabling back pain on physician interview were interviewed.ResultsOf the patients who had sought care for back pain,21% indicated they had not had back pain when interviewed 4–16 months later. Episodes of pain that occurred more than 8 months before the interview tended to be recalled as occurring more recently than they actually occurred, confirming “forward telescoping” of the illness episode. Only 3% of the individuals without functionally impairing pain reported such pain on a separate interview.ConclusionsLack of recall occurs regarding acute low back pain, usually a self-limited illness. This potential under-estimate of back pain prevalence may be balanced by forward telescoping of the date of illness occurrence.

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Study DesignA cohort of 1848 workers, representative of all sectors of industry, who were compensated for a low back injury in 1988 but not in the previous 2 years, was followed over 24 months.ObjectivesTo determine the prognostic value of the physician's initial diagnosis of back problems.Summary of Background DataIn the absence of a standardized classification of diagnoses of back pain, this study aimed to provide an element of validity to a classification previously proposed that consists of “specific” and “nonspecific” back pain.MethodsMedical charts were reviewed at the Quebec Worker's Compensation Board to extract the diagnosis made by the treating physicians within 7 days of the first day of absence from work. Diagnoses were categorized into “specific” (lesions of vertebrae and discs) and “nonspecific” [pain, sprains, and strains). The history of compensated work absence for low back pain in the following 24 months was obtained.ResultsA specific diagnosis was found in 8.9% (165) of the workers, accounting for 31.0% of the patients who accumulated 6 months or more of absence in 2 years. Increasing age and daily amount of compensation also were associated with an increased risk of chronicity.ConclusionsThe physician's initial diagnosis was highly associated with the risk of chronicity. The explanation for this result is complex, involving the nature of the underlying lesion as well as the impact of the diagnosis “label” on the worker and on the physician-patient relationship.

ISSN:0362-2436    

出版商:OVID    

年代:1995

数据来源: OVID