TY - JOUR
T1 - A study on the use of the Osstell apparatus to evaluate pedicle screw stability
T2 - An in-vitro study using micro-CT
AU - Nakashima, Daisuke
AU - Ishii, Ken
AU - Matsumoto, Morio
AU - Nakamura, Masaya
AU - Nagura, Takeo
N1 - Publisher Copyright:
© 2018 Nakashima et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2018/6
Y1 - 2018/6
N2 - Pull-out force and insertion torque have not been generally used as intraoperative measures for the evaluation of pedicle screw stability because of their invasiveness. On the other hand, resonance frequency analysis is a non-invasive and repeatable technique that has been clinically used in dentistry to evaluate implant stability e.g. by the Osstell apparatus. In this study, the characteristics of the implant stability quotient (ISQ) value obtained by the Osstell apparatus in the field of spinal surgery were investigated. Biomechanical test materials simulating human bone were used to provide a comparative platform for evaluating each fixation strength measure, including pull-out force, insertion torque, and the ISQ value. To perform pull-out force measurement and to repeat pedicle screw insertion and removal, loosening was artificially created, and its effect was investigated. The grade of loosening was quantified on a micro-CT image after pedicle screw removal. In the comparison of the 3 fixation strength measures, the correlations of the ISQ value with the pull-out force (R 2 = 0.339 p <0.0001) and the insertion torque (R 2 = 0.337 p <0.0001) were lower than the correlation between pull-out force and insertion torque (R 2 = 0.918 p <0.0001). On a micro-CT study, the material volume of the internal threads disappeared after destruction of its integrity due to repeated pedicle screw insertion and removal. Material integrity destruction of the internal threads decreased only the pull-out force and the insertion torque, but it did not affect the ISQ value. The ISQ value only decreased when the material volume of the internal threads disappeared, probably because the ISQ value reflects the resistance against a force in the perpendicular direction of the screw, unlike the conventional measures of fixation strength, such as pull-out force and insertion torque, which reflect axial load.
AB - Pull-out force and insertion torque have not been generally used as intraoperative measures for the evaluation of pedicle screw stability because of their invasiveness. On the other hand, resonance frequency analysis is a non-invasive and repeatable technique that has been clinically used in dentistry to evaluate implant stability e.g. by the Osstell apparatus. In this study, the characteristics of the implant stability quotient (ISQ) value obtained by the Osstell apparatus in the field of spinal surgery were investigated. Biomechanical test materials simulating human bone were used to provide a comparative platform for evaluating each fixation strength measure, including pull-out force, insertion torque, and the ISQ value. To perform pull-out force measurement and to repeat pedicle screw insertion and removal, loosening was artificially created, and its effect was investigated. The grade of loosening was quantified on a micro-CT image after pedicle screw removal. In the comparison of the 3 fixation strength measures, the correlations of the ISQ value with the pull-out force (R 2 = 0.339 p <0.0001) and the insertion torque (R 2 = 0.337 p <0.0001) were lower than the correlation between pull-out force and insertion torque (R 2 = 0.918 p <0.0001). On a micro-CT study, the material volume of the internal threads disappeared after destruction of its integrity due to repeated pedicle screw insertion and removal. Material integrity destruction of the internal threads decreased only the pull-out force and the insertion torque, but it did not affect the ISQ value. The ISQ value only decreased when the material volume of the internal threads disappeared, probably because the ISQ value reflects the resistance against a force in the perpendicular direction of the screw, unlike the conventional measures of fixation strength, such as pull-out force and insertion torque, which reflect axial load.
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U2 - 10.1371/journal.pone.0199362
DO - 10.1371/journal.pone.0199362
M3 - Article
C2 - 29953480
AN - SCOPUS:85049145467
VL - 13
JO - PLoS One
JF - PLoS One
SN - 1932-6203
IS - 6
M1 - e0199362.
ER -