Spine
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Cross-sectional study comparing normal subjects and patients with lumbar disc herniation. ⋯ In the patients with lumbar disc herniation, muscle strength of the trunk and knees was decreased to a similar extent. Weaker knee strength was found on either side of the lower extremity in the patients with unilateral sciatica, regardless of its location.
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Eighteen human torsos were used in three experiments (A, B, and C) to determine the changes in sagittal motion due to three different sequences of three surgical releases. ⋯ Sagittal plane motion in the thoracic spine is influenced by all three structures tested in this experiment. Overall, the radical discectomy provides the greatest increase in total ROM and in extension compared with the other two releases. The second most influential release is the combination of sternal osteotomy plus costosternal release (i.e., sternal release), particularly in extension (correction of kyphosis). When two releases are done in sequence, radical discectomy plus sternal release provides the greatest increase in total ROM and in extension. Overall, total facetectomy is the least effective release. These data have relevance for surgical strategies in the correction of thoracic kyphosis or lordosis and suggest a potential role for sternal osteotomy and costosternal release in severe and rigid upper thoracic kyphosis.
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A retrospective study. ⋯ The incidence of proximal junctional kyphosis at 7.3 years postoperation was 26% and did not progress significantly after 2 years postoperation. Risk factors for developing PJK were an associated thoracoplasty, hybrid instrumentation (proximal hooks and distal pedicle screws), and a preoperative larger sagittal thoracic Cobb angle (T5-T12 > 40 degrees). The SRS-24 outcome instrument was not affected by PJK.
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This study is a retrospective review of 752 patients with adult spinal deformity enrolled in a multicenter prospective database in 2002 and 2003. Patients with positive sagittal balance (N = 352) were further evaluated regarding radiographic parameters and health status measures, including the Scoliosis Research Society patient questionnaire, MOS short form-12, and Oswestry Disability Index. ⋯ This study shows that although even mildly positive sagittal balance is somewhat detrimental, severity of symptoms increases in a linear fashion with progressive sagittal imbalance. The results also show that kyphosis is more favorable in the upper thoracic region but very poorly tolerated in the lumbar spine.
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Comparative Study
Value of dermatomal somatosensory evoked potentials in detecting acute nerve root injury: an experimental study with special emphasis on stimulus intensity.
Dermatomal somatosensory-evoked potentials (D-SSEPs) in rats were recorded at the spinal level after L2-, L4-, and L5-dermatome stimulation. Pre- and post-transection patterns and rates of change of corresponding nerve roots were compared to determine accuracy. ⋯ D-SSEP is valuable for detecting acute single nerve root injury. In clinical settings, submaximal dermatomal stimulation identifies conduction abnormalities more consistently and with fewer false negatives and false positives than does supramaximal stimulation. We recommend submaximal stimulation.