Validation of vibration testing for the assessment of the mechanical properties of human lumbar motion segments

详细信息	查看全文 | 推荐本文 |

• 作者：S.J.P.M. van Engelen^a ; ^b ; M.H.M. Ellenbroek^c ; B.J. van Royen^a ; ^d ; A. de Boer^c ; J.H. van Dieë ; n^a ; ^b ; ^{j.h.van.dieen@vu.nl} ; ^{j_h_van_dieen@fbw.vu.nl}
• 关键词：Biomechanics ; Human lumbar spine ; Experimental modal analysis ; Validation
• 刊名：Journal of Biomechanics
• 出版年：2012
• 期刊代码：144_00219290
• 类别：med
• 出版时间：26 June, 2012
• 卷：45
• 期：10
• 页码：1753-1758
• 文件大小：490 K

摘要

Experimental modal analysis is a non-destructive measurement technique, which applies low forces and small deformations to assess the integrity of a structure. It is therefore a promising method to study the mechanical properties of the spine in vivo. Previously, modal parameters successfully revealed artificially induced spinal injuries. The question remains however, whether experimental modal analysis can be applied successfully in human spinal segments with mechanical changes due to physiological processes. Since quasi-static mechanical testing is considered the 鈥済old standard鈥?for assessing intervertebral stiffness, the purpose of our study was to examine if the mechanical properties derived from vibration testing and quasi-static testing correlate.

Six cadaver human spines (L1-L5) were loaded quasi-statically in bending and torsion, while an optical system measured the angular rotations of the individual motion segments. Subsequently, the polysegmental spines were divided into L2-L3 and L4-L5 segments and a shaker was used to vibrate the upper vertebra, while its response was obtained from accelerometers in anteroposterior and mediolateral directions. From the resulting frequency response function the eigenfrequencies (ratio between stiffness and mass) and vibration modes (pattern of motion) were determined.

The vibration results showed clear eigenfrequencies for flexion-extension (mean 121.83 Hz, SD 40.05 Hz), lateroflexion (mean 132.17, SD 34.80 Hz) and axial rotation (mean 236.17 Hz, SD 81.45 Hz). Furthermore, the correlation between static and dynamic tests was significant (r=0.73, p=0.01). In conclusion, the findings from this study show that experimental modal analysis is a valid method to assess the mechanical properties of human lumbar motion segments.