摘要:

Sagittal magnetic resonance images of the normal craniovertebral junction in 25 patients were examined for visualization of bony, synovial, and ligamentous structures. The excellent delineation of soft tissue by magnetic resonance imaging enabled recognition of the joint space between the dens and anterior arch of C1 in 14 out of 25 patients. High-signal-intensity tissue was noted immediately superior to the dens in all patients; an anatomic specimen confirmed the fibrofatty nature of this tissue. The medullary space of the dens had lower signal intensity than did the marrow in the body of C2 in more than one half of the cases. Additional thin-section images suggested that this was a partial-volume artifact. Understanding of the normal appearances of structures in this region is necessary to assess correctly the presence or absence of disease.

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Four patients with traumatic occipitoatlantal dislocation are presented. The dislocations were the result of rapid deceleration motor vehicle accidents. The mechanism of injury was by hyperextension-rotation combined with a distraction force. Three patients sustained multiple inju- ries. Neurologic findings were variable. One patient with complete cord transection and closed head trauma died 4 days after the injury. In the three surviving patients, the occipitoatlantal dislocation was not diagnosed by the initial examiner. Prompt recognition and stabilization are essential to avoid further neurologic injury. Care must be taken not to increase the dislocation. A halo applied before operation facilitates reduction and allows posterior occipitoatlantal fusion to be performed under optimum conditions.

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The three-dimensional rotational biomechanical properties of several different types of posterior stabilizing procedures are reported. A severe ligamentous and bony injury was simulated with three vertebral body humancervical spine segments. Good stabilization was noted for all of the repairs in flexion loading. Without polymethylmethacrylate supplementation, none of the repairs was stable in extension. All of the repairs provided reasonable stabilization for lateral bending except for the posterior wiring without methacrylate, and all but the posterior wiring and facet fusion provided reasonable stabilization against axial rotation loading. The supplementation of all of these repairs with polymethylmethacrylate added con- siderably to the stability of all the constraints. These findings may be useful in clinical decision-making for determining the kind of repairs and postoperative brace protection to use.

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Twenty-two patients who underwent a surgical decompressive procedure for cervical spondylotic myelopathy were studied with magnetic resonance imaging to evalu ate the effectiveness of their decompressive procedures. Twelve patients were judged as adequately decom pressed by magnetic resonance imaging criteria. Ten patients exhibited evidence of residual cord indentation. This along with cord atrophy, gliosis, and abnormal spine curvature presumably contributed to, residual deficit in several patients. One patient underwent a second decom pressive procedure for residual cord indentation, which subsequently improved, as seen on his second postop erative magnetic resonance image. Magnetic resonance imaging was useful in distinguishing mechanical prob lems from intrinsic cord damage or atrophy. Magnetic resonance imaging should be used after operation in patients with residual deficit to detect patients who may be considered for a second decompressive procedure.

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The data from a prospective study of 508 spine injuries were reviewed to determine the incidence of multiple noncontiguous spine fractures. All patients were exam ined at admission and at 1 and 2 years postinjury. This series identified 77 (15.2%) multilevel fractures. Motor vehicle accidents were the primary cause of these frac tures. The incidence of neurologic injury was not signifi cantly different between multiple noncontiguous and sin gle fractures. Failure to use seat belts and ejection from the vehicle were the main factors associated with multiple noncontiguous spine injuries. Seven major fracture pat terns were identified, which accounted for 60% of these injuries. The prognosis for multilevel spine fractures was not significantly worse than that for single-level injuries

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

This article compares the postoperative course of 40 patients who had Harrington instrumentation with 40 patients who had Harrington instrumentation and inter spinous process segmental instrumentation of unstable thoracolumbar fractures and reviews the findings. The two groups of patients were otherwise homogeneous, and average operative time, total blood loss, and days to oral intake were similar for both groups of patients. On average, however, patients undergoing interspinous pro cess segmental instrumentation were out of bed sooner (4.5 versus 7.7 days, P < O.OOOl), discharged sooner (32 versus 38 days, P < 0.079), and brace-free earlier (2.1 versus 5.9 months, P < 0,001) and had fewer fixation related complications than did patients undergoing Har rington instrumentation alone. Comparison of average hospital costs documented a savings of $5,160 for the typical patient undergoing interspinous process seg mental instrumentation.

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The hypothesis for the mechanism of production of scoliosis, advanced on the basis of morphometric and morphologic studies in human thoracic skeleton, finds further support in the results of an experimental study inrabbits described herein. The removal of transverse processes alone resulted in the production of scoliosis and lordosis. When both transverse processes and facet joints were removed, scoliosis developed rapidly and was considerable. When paraspinal muscles were incised on one side only, however, this resulted in the development of lordosis alone. The convexity of the curve was always toward the operated side, and the apex was almost always at the lowest operated segment. Lordosis was limited to within the operated area. The results of the experiment indicate that scoliosis resulted because of the asymmetry in load transmission through the ribs to the vertebral column in rabbits.

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

This article reports on a study of 51 consecutive patients (83 lumbar discs) with back pain who underwent anterior interbody lumbar fusion or combined anterior and posterior fusion at the same operation during a 2-year period. All patients met the criteria for diagnosis of a painful internal disc disruption andlor failed back syndrome and have had a lengthy trial of conservative treatment consisting of rest, physical therapy, back support, nonsteroidal anti-inflammatory drug therapy, and guarded activity; this treatment was often supplemented by epidural cortisone injections, pain management, and functional rehabilitation. Patients with prolonged back pain who failed with conservative care after a minimum of 12 months of severely disabling symptoms were selected for surgery on the basis of a positive dynamic discogram reproducing their exact pain and demonstrating a morphologically degenerative disc (internal disc disruption). For the purpose of this study, patients were categorized into three groups and followed up for 15–36 months after the operation. There were no deaths or major complications, and the overall success in achieving measurable diminution of preoperative pain was 80%. This article discusses preliminary conclusions on the efficacy and safety on anterior and anteroposterior fusion for lumbar disc pain.

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

To assess the significance of regional quantitative computed tomography measurements of bone density with respect to mechanical strength in the human lumbar spine, 58 vertebrae (from 12 males, 10 females) were scanned in vitro with multiple-thin-slice quantitative computed tomography and then compressed to fracture. With computer graphics, 18 specific regions of physical density and 10 combination averages of density were identified within each vertebral body. To ensure the statistical independence of data, the individual vertebral specimens were assigned to one of three groups (Tll-Ll, L2-L3, or L4-L5). Use of best-subsets procedures resulted in regression models to predict fracture strength. These models used specific regional density values and often the age and sex of the donors. The correlation coefficients that resulted from the multiple regression models ranged from r = 0.88 to r = 0.95. When the density values were multiplied by the minimum cross-sectional area of the vertebral body, similar regional density averages were selected, and the predictive values were slightly improved (r = 0.94–0.97). The heterogeneity of the density samples (measured as standard deviation) in multiple regression fashion also produced strong correlation coefficients (r = 0.88494). The bone density in an anterior cylinder of the midplane region, the location measured most often in quantitative computed tomography densitometry, was strongly correlated (r = 0.85) to fracture load for the T12-L1 group (N = 20), but was not significant for the other two groups of vertebrae. The cancellous bone density from the female data was not found to be significantly different from the male data set. These data suggest that when the density of specific regions in the vertebral main body are measured, most of the variance in the whole-bone strength could be predicted, and these optimal regions (a relative measure of cancellous heterogeneity) appeared to vary with spine level. Using the bone density from multiple regions of the cancellous interior may ultimately yield clinically useful information relevant to patient treatment decisions]

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Bilateral surface and fine-wire electromyographic activity from the erector spinae at the 14–5 interspace was recorded from 10 female subjects during flexion, extension, rotation to righvleft, and sidebending to righvleft. Finewire electrodes demonstrated significant left-right electromyographic differences during terminal flexion. Surface and fine-wire electromyographic recordings demonstrated a symmetric pattern of activity during extension. A symmetric pattern of erector spinae activity was observed during rotation using fine-wire electrodes but not from surface electrodes. Increased electromyographic activity from the contralateral erector spinae was detected by the surface electrodes during sidebending to neutral movements]

ISSN:0362-2436    

出版商:OVID    

年代:1991

数据来源: OVID