The spine journal : official journal of the North American Spine Society
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Various methodologies have been used in attempting to elucidate a standard method for calculating minimal clinically important difference (MCID). A consensus-based decision (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials [IMMPACT] group) suggested a 30% reduction from baseline as a means to define the MCID of self-report back pain measures. Additionally, important psychometric issues need to be addressed regarding use of an independent measure of the same construct as an external criterion, instead of simply using another self-report measure, when using an anchor-based approach to MCID. ⋯ When objective and independent criteria are used (socioeconomic outcomes) in a CDOSD cohort, the 30% improvement in the ODI and SF-36 may not be a valid MCID index. This replicates similar conclusions made by an independent research group using a distribution-based approach to MCID. The validity of the MCID concept rests on future research using objective external criteria. Moreover, there remains a question whether the term "important" in MCID can be unequivocally and operationally defined as a reliable construct.
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Sitting is associated with loss of the lumbar lordosis, intervertebral disc (IVD) compression, and height loss, possibly increasing the risk of lower back pain. With a trend toward more sitting jobs worldwide, practical strategies for preventing lumbar flattening and potentially associated low back pain (LBP) are important. ⋯ Seated upright MRI and stadiometry, as performed in this study, appear to be feasible methods for detecting compressive and decompressive spinal changes associated with normal sitting and, alternately, seated unloading exercises. Larger studies are encouraged to determine normative values of our study measurements and to determine if morphological changes induced by seated unloading predict treatment response and/or reductions in the incidence of sitting-related LBP.
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Comparative Study
Biomechanical comparison of single- and two-level cervical arthroplasty versus arthrodesis: effect on adjacent-level spinal kinematics.
The use of motion-preserving spinal implants versus conventional arthrodesis instrumentation systems, which stabilize operative segments, necessitates improved understanding of their effect on spinal kinematics and the biomechanically optimal method for surgical reconstruction. ⋯ This study highlights the biomechanical effects of single- and two-level cervical arthroplasty versus single- and two-level arthrodesis on four functional spinal levels (C4-T1). Operative-level ROM was preserved with single- and two-level arthroplasty under all loading modes. The distal adjacent level (C7-T1) demonstrated the greatest increase among the four levels in ROM compared with the intact condition after two-level arthrodesis. These kinematic findings were corroborated by changes in the adjacent-level centers of rotation after arthrodesis and may suggest a biomechanical cause of adjacent-level disease secondary to cervical arthrodesis.