Develop a methodology to assess the long term mechanical behavior of intervertebral discs by utilizing novel sequential state testing. Bovine functional spinal units were sequentially mechanically tested in (1) native (n=8), (2) degenerated (n=4), and (3) treated states (n=4). At stage (2), artificial degeneration was created using rapid enzymatic degeneration, followed by a 24 hour hold period under static load at 42°C. At stage (3), nucleus augmentation treatments were injected with a hydrogel or a ‘sham’ (water, chondroitin sulfate) injection. The mechanical protocol employed applied a static load hold period followed by cyclic compressive loading between ∼350 and 750 N at 1 Hz. 1000 cycles were applied at each stage, and the final test on each specimen was extended up to 20000 cycles. To verify if test time can be reduced, functions were fitted using stiffness data up to 100, 1000, 2500, 5000, 10000 and 20000 cycles. Linear regression for the native specimens comparing the stiffness at various cycles to the stiffness at 20000 cycles was completed.Abstract
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The use of musculo-skeletal MRI is increasing at spectacular rate, however there have been few rigorous evaluations of its’ clinical effectiveness. This study was conducted to assess the impact of MRI of the wrist on clinical diagnosis and patient management. A controlled observational study was performed, in which referring clinicians completed questionnaires on diagnosis and intended management before and after wrist MRI. We analysed 118 consecutive patients referred for MRI of the wrist, to the magnetic resonance imaging units at a regional teaching hospital and a large district general hospital. We assessed: changes in clinicians’ leading and subsidiary diagnoses after MRI; their certainty of these diagnoses; and changes in intended patient management. Five patients had incorrectly completed requests, ten cancelled their appointments and two could not tolerate the MR examination. Complete follow up data is available for 98/101 patients with correctly completed request forms who were examined. The clinical diagnosis changed in 55 of 98 patients (56%). Diagnostic certainty increased in 23 of the remaining 43 patients (53%). Clinicians reported that MRI had substantially improved their understanding of the patients’ disease in 67/98 (68%) patients. There was a change in management in 46/98 (47%) patients, with a shift away from operative treatment. 28 out of 98 (29%) patients were discharged without further investigation. MRI was similarly effective in a regional teaching centre and a district general hospital. Magnetic resonance imaging of the wrist influences clinicians’ diagnoses and management plans. These results demonstrate the clinical effectiveness of MRI of the wrist in both a regional teaching centre and a district general hospital.
