Nicolaus Steno:Biography and Original Papers of a 17th Century Scientist,Springer,Heidelberg,2013,739 pp.,ISBN 978-3-642-25078-1,ISBN 978-3-642-25079-8(e-Book),DOI 10.1007/978-3-642-25079-8.Nicolaus Steno(Niels Stense...Nicolaus Steno:Biography and Original Papers of a 17th Century Scientist,Springer,Heidelberg,2013,739 pp.,ISBN 978-3-642-25078-1,ISBN 978-3-642-25079-8(e-Book),DOI 10.1007/978-3-642-25079-8.Nicolaus Steno(Niels Stensen,1638-1686)is best known to historians of the geological sciences for his work that provided the basis of modern geology.He introduced a method for interpreting the relationship between containing bodies and contained ones i.e.‘solids within solids’as a basis for the interpretation of the history of the earth.展开更多
There are few biomechanical studies on Interspinous Process Implants (IPD);however none investigate the amount of wear on spinous processes. Therefore the objective of the present study was to investigate the effect o...There are few biomechanical studies on Interspinous Process Implants (IPD);however none investigate the amount of wear on spinous processes. Therefore the objective of the present study was to investigate the effect of repetitive loading of the IPD Aperius on the spinous processes in a biomechanical porcine model. For comparison, three patients treated surgically with the same device have been followed for one to two years clinically and with image analyses (X-rays, MRI, CT-scans). Four lumbar spines from 6 months old porcine were divided into seven segments, which received IPD. The segments were exposed to 20,000 cyclical loads. Afterwards the deformation (wear) of the segments was registered. The wear of the spinous processes was measured in mm on a following CT-scan. Additionally, the wear of the ex-vivo was compared to that of the spinous processes investigated by CT-scans or X-ray in three patients treated surgically with the same interspinous implant. The mean maximal deformation of porcine specimens was 1.79 mm (SD 0.25) with the largest deformation occurring in the first quarter of the loading (<5000 cycles). The mean wear of the spinous processes after loading was 6.57 mm. A similar level of wear (mean 12.7 mm) of the spinous processes was detected in the patients. The Aperius IPD creates significant wear on the spinous processes in an experimental biomechanical study. Similar wear of the spinous processes is also present in patients treated with the same device post-operatively. How these findings influence the short and long term result of this implant device remains to be investigated in further biomechanical as well as clinical studies. For future development of this type of devices a proper selection of materials and design is essential to minimize wear effects on the spinous processes and thereby increases the possibilities for the devices to function as suggested.展开更多
文摘Nicolaus Steno:Biography and Original Papers of a 17th Century Scientist,Springer,Heidelberg,2013,739 pp.,ISBN 978-3-642-25078-1,ISBN 978-3-642-25079-8(e-Book),DOI 10.1007/978-3-642-25079-8.Nicolaus Steno(Niels Stensen,1638-1686)is best known to historians of the geological sciences for his work that provided the basis of modern geology.He introduced a method for interpreting the relationship between containing bodies and contained ones i.e.‘solids within solids’as a basis for the interpretation of the history of the earth.
文摘There are few biomechanical studies on Interspinous Process Implants (IPD);however none investigate the amount of wear on spinous processes. Therefore the objective of the present study was to investigate the effect of repetitive loading of the IPD Aperius on the spinous processes in a biomechanical porcine model. For comparison, three patients treated surgically with the same device have been followed for one to two years clinically and with image analyses (X-rays, MRI, CT-scans). Four lumbar spines from 6 months old porcine were divided into seven segments, which received IPD. The segments were exposed to 20,000 cyclical loads. Afterwards the deformation (wear) of the segments was registered. The wear of the spinous processes was measured in mm on a following CT-scan. Additionally, the wear of the ex-vivo was compared to that of the spinous processes investigated by CT-scans or X-ray in three patients treated surgically with the same interspinous implant. The mean maximal deformation of porcine specimens was 1.79 mm (SD 0.25) with the largest deformation occurring in the first quarter of the loading (<5000 cycles). The mean wear of the spinous processes after loading was 6.57 mm. A similar level of wear (mean 12.7 mm) of the spinous processes was detected in the patients. The Aperius IPD creates significant wear on the spinous processes in an experimental biomechanical study. Similar wear of the spinous processes is also present in patients treated with the same device post-operatively. How these findings influence the short and long term result of this implant device remains to be investigated in further biomechanical as well as clinical studies. For future development of this type of devices a proper selection of materials and design is essential to minimize wear effects on the spinous processes and thereby increases the possibilities for the devices to function as suggested.
