Spine

NOREN, R ; TRAFIMOW, J ; ANDERSSON, G B J ; HUCKMAN, M S

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In this study, the relationship between facet geometry (joint angle and tropism) and disc degeneration was analyzed. Magnetic resonance imaging and computed tomographic scans of 46 subjects less than 50 years of age were evaluated. Magnetic resonance imaging was used to determine disc degeneration, and computed tomography was used to measure facet joint angles and determine tropism. Subjects with tropism had a significantly higher prevalence of disc degeneration at all three lumbar levels examined (L3-4, L4-5, L5-S1). The average facet angles increased from L3-4 to L4-5 and further to the L5-S1 level. There was no statistically significant relationship between the magnitude of the angle and the presence of disc degeneration at any of the three levels. It was concluded that the risk of disc degeneration is increased in the presence of facet joint tropism.

SAITO, TETSUFUMI ; YAMAMURO, TAKAO ; SHIKATA, JITSUHIKO ; OKA, MASANORI ; TSUTSUMI, SADAMI

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Postlaminectomy deformities were simulated in the cervical or cervicothoracic spine by the use of a displacement incremental method based on finite-element analysis combined with composite material and spanning element theory. The simulation analyses revealed that the primary cause of postlaminectomy deformity was the resection of one or more spinous processes and/or posterior ligaments (ie, ligamenta flava, supraspinous, and interspinous ligaments). After their removal, the tensile stresses that were preoperatively distributed through the posterior ligaments were transferred to the facets. This led to an imbalance of the stresses on the spinal bodies, causing deformity. The gravitational center of the head determined whether the deformity would develop as a kyphosis or increasing lordosis. As the elastic modulus of the soft tissue composites (eg, end plates, ligaments, and facets) increased, a kyphotic deformity changed gradually from swan-neck deformity, to extreme kyphotic deformity with a large curvature, and finally to a straightening deformity. Progressive kyphotic deformity is found only in children.

PAQUET, NICOLE ; MALOUIN, FRANCINE ; RICHARDS, CAROL L.; DIONNE, JEAN P.; COMEAU, FRANCOIS

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This study was designed to determine the validity and reliability of a new electrogoniometer devised and developed for the measurement of sagittal dorsolumbar movements (T8-S1). The validity was measured in 10 normal subjects by comparison of the angle values obtained with the electrogoniometer with those obtained with the twoinclinometer method previously validated with x-ray measurements. The total range of movement was divided into 5° steps, and the angle value obtained with both methods was recorded at each of these steps. The testing procedure was repeated (retest) after removal and reattachment of the electrogoniometer. Because the potentiometer of the electrogoniometer measures angular changes indirectly from changes in the curvature of a flexible slat, a special individual calibration procedure was applied, and computation of the electrogoniometric angles (Ec) representing the dorsolumbar movement was made by software. Regression analysis of Ec in relation to corresponding inclinometric angles gave a slope of 1.03 and a Pearson's correlation coefficient of 0.97, indicating a high concurrent validity between the two methods. The intraclass correlation coefficient between test and retest (ICC = 0.982) confirmed the high reproducibility of the measurement procedures. The length of the slat can be changed to adapt the electrogoniometric system to different statures. Under standardized conditions, this new electrogoniometer can provide continuous measurements of sagittal dorsolumbar movements that are reproducible with an accuracy comparable to that obtained with the two-inclinometer method.

BERNICK, SOL ; WALKER, J M ; PAULE, W J

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This study deals with age changes in the anulus fibrosus of the lumbar intervertebral discs of human individuals 21-83 years of age. The anular laminas from individuals less than 40 years of age consisted of obliquely orientated collagen fibers exhibiting a pennate arrangement. These fibers were intensely argyrophilic after silver nitrate impregnation. The fibers and surrounding substance appeared light pink after exposure to the periodicacid- Schiff (PAS) reaction and blue with alcian blue complex. Beginning during middle age and continuing into the eighth decade, there was a progressive degeneration of the laminas. The breakdown of the intact laminas was characterized by the fraying, splitting, and loss of collagen fibers. The newly formed spaces became filled with intense PAS-positive material. In addition, there was a continual deposition of chondroid substance in the anuluses of the aging discs. This phenomenon was not seen in the young disc. These age related changes lead to a loss of integrity to the disc, which may be a factor in disc pathology.

HAIG, ANDREW J.

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STOKES, I A F

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BERG, EUGENE E.; GILPIN, ALBERT T.

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STEPHENS, M M ; EVANS, J H ; O'BRIEN, J P

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The lumbar intervertebral foramens of 20 isolated cadaveric spines were investigated by the use of a molding technique to assess their dimensions accurately and how intervertebral disc pathology altered their configuration. Oval foramens predominated over auricularly shaped foramens when the disc was normal, but when the disc was abnormal, the converse was true. Foraminal size varied from 40 to 160 mm2but showed great variation even at individual levels; these were not accurately reflected by simple radiologic measurements.

ROSESN, CHARLES D.

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BUSH, KEITH ; HILLER, SYLVIA

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The management of sciatica due to lumbar nerve root compromise remains controversial, probably because few well-controlled studies of conservative management have been performed. This preliminary study assesses the efficacy of epidural injections of 80 mg triamcinolone acetonide plus 0.5% procaine hydrochloride in saline, administered via the caudal route, in a double-blind, placebo controlled trial with 1 year follow-up. Twenty-three patients were entered into the study: 12 received treatment and 11 placebo. The active group showed significant pain relief (P=0.02) and a significant increase in mobility (P=0.01) at 4 weeks, which resulted in improved quality of life (P=0.02). At 1 year, subjective and objective measures improved in both groups. The improvement was greater in the actively treated group, but only the objective assessment (straight leg raise) was statistically significant.