摘要:

Study Design.Using anin vivointerbody arthrodesis model, the efficacy of the Bagby and Kuslich (BAK) device packed with recombinant human osteogenic protein-1 (rhOP-1) was evaluated.Objectives.To compare the efficacy of osteogenic protein with that of autograft for interbody arthrodesis, with fusion success based on biomechanical, histologic, and radiographic analyses.Summary of Background Data.The use of recombinant human bone morphogenetic proteins (rhBMPs) as osteoinductive bone graft substitutes or expanders has recently gained considerable research interest, particularly when applied in posterolateral arthrodesis. However, whether these results can be extrapolated to a successful interbody spinal arthrodesis remains uncertain.Methods.Twelve sheep underwent a multilevel thoracic spinal decompression by thoracoscopic approach. Three noncontiguous destabilization sites (T5-T6, T7-T8, T9-T10) were prepared and randomly treated as follows. Control group treatments were nonsurgical, destabilization alone, and empty BAK. Experimental groups were treated with autograft alone, BAK device packed with autograft, or BAK device packed with rhOP-1. Four months after surgery, interbody fusion status was quantified by biomechanical testing, computed tomography, microradiography, and histomorphometry.Results.Results of biomechanical analysis showed statistically higher segmental stiffness levels when comparing the control and experimental groups with four of the five testing methods (P< 0.05). Computed tomography and microradiography characterized destabilization alone as producing one fusion in six preparations; the empty BAK, two in six;, autograft alone, four in eight; BAK with autograft, five in eight; and BAK with rhOP-1 group, six in eight-all evidenced by woven trabecular bone spanning the fusion sites. Histomorphometry yielded significantly more trabecular bone formation at the fusion sites in the three experimental groups than in the two control groups (P< 0.05).Conclusions.Interbody spinal fusions showing biomechanical and histomorphometric equivalency to autologous fusions have been achieved with rhOP-1. The functional unit stability and histologic osteointegration evidenced by the BAK/rhOP-1 complex shows this interbody arthrodesis technique to be a viable alternative toconventional autologous iliac crest, thereby obviating the need for an iliac crest donor site and associated patient morbidity.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.Facet joints from sheep lumbar spines were examined for histologic evidence of osteoarthrosis after anular incision.Objectives.To describe the sequence of changes in facet joints in an animal model of disc degeneration.Summary of Background Data.There are many studies with results showing a link between facet joint osteoarthrosis and disc degeneration, but the development of osteoarthrosis in facet joints has not been observed in a controlled study of disc degeneration.Methods.Histologic features of facet joint degeneration were compared with established descriptions of human osteoarthrosis, and the sequence of changes was documented in a controlled prospective study of disc degeneration.Results.Osteoarthrosis in sheep lumbar facet joints is similar to that described in human joints and develops in response to anular injury. Discs degenerate relatively soon after anular incision, but there is a long delay in the appearance of significant changes to the facet joints at the level of anular incision and adjacent levels.Conclusions.The results shows that facet joints in sheep undergo osteoarthrotic changes in response to disc degeneration and confirm the sheep as a suitable model for the study of degenerative spinal disorders.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.A radiographic study of the effect of a modern orthotic device in the treatment of rheumatoid atlantoaxial subluxation.Objective.To study the ability of a new open-type collar to restrict atlantoaxial subluxation.Summary of Background Data.Atlantoaxial subluxation is common in rheumatoid arthritis, and thus, the development of conservative treatments is important. It has been shown that a custom-made stiff collar significantly restricts atlantoaxial subluxation in approximately half of patients with unstable atlantoaxial subluxation.Methods.In 30 successive patients with rheumatoid atlantoaxial subluxation, lateral view radiographs were taken in flexion, extension, and neutral positions without a collar and in flexion with the Headmaster collar.Results.The mean atlantoaxial distance during flexion was 7.1 ± 1.8 mm and during extension was 1.0 ± 1.0 mm, and the mean instability was 6.1 ± 2.3 mm. In the 20 cases with the greatest stabilizing effect, the mean atlantoaxial distance during flexion with a collar was 1.1 ± 1.3 mm, whereas in 10 patients with lesser effect it was 6.7 ± 2.5 mm (P< 0.0001). The lesser stabilizing effect was associated with the presence of atlantoaxial subluxation in the neutral position.Conclusion.The Headmaster collar is an effective and useful tool in the conservative treatment of simple unstable atlantoaxial subluxation, but an ordinary custommade stiff collar is still often needed. These two collars are complementary, and their selection and use must be determined individually.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.Retrospective study on the results of surgical treatment of compressive cervical myelopathy in patients more than 75 years of age.Objectives.To investigate clinical features and surgical outcomes of compressive cervical myelopathy in aged patients and to discuss the role of surgical treatment.Summary of Background Data.There are few data focused on the outcomes of surgery in patients with cervical myelopathy who are more than 75 years of age.Methods.Seventeen patients with compressive cervical myelopathy who underwent surgery were reviewed. The average age at the time of surgery was 77.2 years. Posterior decompression in 15 patients and anterior decompression in 2 patients were performed. Neurologic deficits before and after surgery were assessed using a scoring system proposed by the Japanese Orthopaedic Association (JOA score). Independence of daily living was evaluated. Radiologic features were examined with radiographs and magnetic resonance imaging. Clinical results were compared with those of patients less than 65 years old as a control.Results.The preoperative mean JOA score was 6.1, the postoperative maximum JOA scores averaged 11.4, and the recovery rate was 48.4%. These were significantly inferior to scores in those less than 65 years of age. All seven of the patients who could not walk even with aids before surgery became independent in daily activities after surgery. At the final follow-up, the mean JOA score had decreased to 10.7 and the recovery rate to 39.1%. Five of nine patients whose follow-up periods were more than 5 years showed decreases in JOA score, although all patients were still ambulatory.Conclusions.Surgical decompression for cervical myelopathy appears to be beneficial, even in patients more than 75 years of age, in improving neurologic function and ability to engage in activities of daily living.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.Thirty-four patients with idiopathic scoliosis who underwent anterior spinal surgery as part of the correction of spinal deformity were studied prospectively. Superior and inferior endplates were harvested and examined histologically for evidence of residual growth activity. This was then correlated with Risser grades, chronologic age, and pubertal status.Objectives.To clarify the correlation between Risser grade and vertebral endplate growth potential in patients with idiopathic scoliosis.Summary of Background Data.The importance of longitudinal spinal growth in patients with idiopathic scoliosis and its correlation with curve progression and the crankshaft phenomenon after posterior fusion are well recognized. The Risser grade, which shows the extent of excursion of the iliac apophysis on serial plain radiographs, is commonly used to estimate residual spinal growth. However, the correlation between the Risser grade and vertebral endplate growth potential in patients with idiopathic scoliosis remains unclear.Methods.Superior and inferior endplates were harvested from these patients and examined histologically for evidence of residual growth. This was correlated with Risser grade, chronologic age, and pubertal status.Results.Risser Grade 5 was found to be the only indicator of cessation of vertebral growth in idiopathic scoliosis. Of the 14 patients with Risser Grade 4, 10 showed significant growth activity in the vertebral endplates. The reliability of Risser Grade 4 increases when combined with chronologic age and time since menarche in female patients.Conclusions.The crankshaft phenomenon is reported to occur only in patients with Risser Grade 2 or less, particularly those with open triradiate cartilages. Our findings of significant endplate growth activity, even in patients with Risser Grade 4, make it unlikely that the crankshaft phenomenon is caused purely by longitudinal spinal growth.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.A cross-sectional, mailed survey on impairment and function using 6361 respondents to the Spinal Cord Dysfunction National Veterans Survey who reported spinal cord injury as the sole cause of their spinal cord dysfunction.Objectives.To establish the concurrent and construct validities of a Self-Reported Functional Measure appropriate for use in patients with spinal cord injuries.Summary of Background Data.Functional assessment is of increasing importance in clinical care, quality assurance, and national health-care planning. There is a conspicuous need for validated functional assessment measures that are rapid, reliable, and appropriate for use in the disabled population.Methods.The correlation was examined of hours of personal assistance, number of affected limbs, amount of motor impairment, and amount of combined limb-motor impairment to Self-Reported Functional Measure response tertile (scores, 13-32, 33-45, 46-52; lower scores indicated worse function).Results.There were statistically significant correlations between Self-Reported Functional Measure score and hours of personal assistance (P< 0.001), the number of affected limbs (P< 0.001), the amount of motor impairment (P< 0.001), and the amount of combined limb-otor impairment (P< 0.001). For example, 87% of people with the most limb-motor impairment (four affected limbs and no useful movement) were in the lowest Self-Reported Functional Measure tertile, compared with 3% of people in the least-affected category of limb-motor impairment. Furthermore, visual, sensory, or memory impairment did not influence the correlation between limb-motor impairment and Self-Reported Functional Measure score.Conclusion.The Self-Reported Functional Measure shows good concurrent and construct validities.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.An experimental study was conducted to evaluate the effect of an unexpected postural perturbation during a lifting task.Objectives.To investigate electromyographic responses in the erector spinae to a postural perturbation, simulating slipping, during an ongoing voluntary lifting movement. It was hypothesized that specific combinations of voluntary movement and postural perturbation present a situation in which injury caused by a rapid switch between conflicting motor commands can occur.Summary of Background Data.Studies of postural perturbations have mainly focused on behavior during static tasks such as quiet, upright standing. To date, there are no published studies of the effect of a perturbation during an ongoing voluntary lifting movement.Methods.Subjects standing on a movable platform were exposed to random perturbations while lifting a 20-kg load. Muscle activity was recorded from flexor and extensor muscles of the trunk and hip. Trunk flexion angle in the sagittal plane was recorded with a video system.Results.Perturbations forward were followed by an increased activity in erector spinae superimposed on the background activation present during the lift, indicating that both the voluntary and postural motor programs caused an activation of erector spinae. During backward perturbation, however, there was a sudden cessation of erector spinae activity followed by an extended period of rapid electromyographic amplitude fluctuations while the trunk was flexing, indicating an eccentric contraction of the erector spinae.Conclusions.This erratic behavior with large electromyographic amplitude fluctuations in the erector spinae after a backward slip during lifting may indicate a rapid switch between voluntary and postural motor programs that require conflicting functions of the back muscles. This may cause rapid force changes in load-carrying tissue, particularly in those surrounding the spine, thus increasing the risk of slip-and-fall-related back injuries.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.A prospective evaluation of the clinical and radiographic outcomes of 71 patients who underwent lumbar fusion, with or without transpedicular instrumentation. The patients completed a questionnaire that determined pain relief, medication use, return to work, and overall satisfaction with surgery.Objectives.To explore the effect, if any, of instrumentation on the outcome of lumbar fusion surgery, according to reports of the patients, and whether there is a correlation between the radiographic determination of a solid fusion and the same patient-reported outcome.Summary of Background Data.The literature on this topic reports pseudarthrosis rates from 0% to 57% and good to excellent results from 56% to 95%. These studies provide no clear-cut recommendations concerning the effect of added lumbar instrumentation on patient-reported outcome in a prospective manner using concurrent control subjects.Methods.The patients were randomized to groups with and without instrumentation after deciding to undergo a lumbar fusion and consenting to enter the study. Radiographs were obtained and questionnaires filled out at 6 weeks, 6 months, 1 year, and 2 years after surgery.Results.There was no statistical difference in patient-reported outcome between the two groups. There was a slight nonsignificant trend toward increased radiographic fusion rate in the group with instrumentation that did not correlate with an increased patient-reported improvement rate.Conclusions.These results do not provide data that indicate a benefit in outcome from added instrumentation in elective lumbar fusions.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID