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A biomechanical comparison between cortical bone trajectory fixation and pedicle screw fixation.

Oshino H, Sakakibara T, Inaba T, Yoshikawa T, Kato T, Kasai Y - J Orthop Surg Res (2015)

Bottom Line: There have been several reports on the pullout strength of cortical bone trajectory (CBT) screws, but only one study has reviewed the stability of functional spine units using the CBT method.The angular displacement from the time of no load to the time of maximum torque was defined as range of motion (ROM), and then, the mean ROM in the bend and rotation tests and the mean rate of relative change of ROM in both the bend and rotation tests were compared between the CBT and PS groups.There were no significant differences between the CBT and PS groups with regard to the mean ROMs and the mean rate of relative change of ROMs in both the bend and rotation tests.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Mie University, Tsu City, Mie, Japan.

ABSTRACT

Purpose: There have been several reports on the pullout strength of cortical bone trajectory (CBT) screws, but only one study has reviewed the stability of functional spine units using the CBT method. The purpose of this study was to compare vertebral stability after CBT fixation with that after pedicle screw (PS) fixation.

Methods: In this study, 20 lumbar spine (L5-6) specimens were assigned to two groups: the CBT model group that underwent CBT screw fixation (n = 10) and the PS model group that underwent pedicle screw fixation (n = 10). Using a six-axis material testing machine, bend and rotation tests were conducted on each model. The angular displacement from the time of no load to the time of maximum torque was defined as range of motion (ROM), and then, the mean ROM in the bend and rotation tests and the mean rate of relative change of ROM in both the bend and rotation tests were compared between the CBT and PS groups.

Results: There were no significant differences between the CBT and PS groups with regard to the mean ROMs and the mean rate of relative change of ROMs in both the bend and rotation tests.

Conclusion: Intervertebral stability after CBT fixation was similar to that after PS fixation.

No MeSH data available.


Related in: MedlinePlus

Mean ROMs of bend test. a CBT group. b PS group
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Fig5: Mean ROMs of bend test. a CBT group. b PS group

Mentions: The mean ROMs of the intact and injured models of both the CBT and PS groups in each of the eight directions in the bend test are shown in Table 1 and Fig. 5. At the results of mean ROMs in the intact and injured model, there were no significant differences between the two groups. The mean ROMs of the fixed model of both the CBT and PS groups in each of the eight directions in the bend test are shown in Table 1 and Fig. 5. The mean ROMs in the CBT group ranged from 1.8° to 2.3°, and the mean ROMs in the PS group ranged from 2.2° to 3.2°, indicating that mean ROMs in the CBT group were slightly lesser than those in the PS group. However, there were no significant differences in the mean ROMs between the CBT and PS groups. In all eight directions, the mean rates of relative change of ROMs were slightly lower in the CBT group than in the PS group (Table 2); however, there were no significant differences in the relative change between the two groups.Table 1


A biomechanical comparison between cortical bone trajectory fixation and pedicle screw fixation.

Oshino H, Sakakibara T, Inaba T, Yoshikawa T, Kato T, Kasai Y - J Orthop Surg Res (2015)

Mean ROMs of bend test. a CBT group. b PS group
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4537537&req=5

Fig5: Mean ROMs of bend test. a CBT group. b PS group
Mentions: The mean ROMs of the intact and injured models of both the CBT and PS groups in each of the eight directions in the bend test are shown in Table 1 and Fig. 5. At the results of mean ROMs in the intact and injured model, there were no significant differences between the two groups. The mean ROMs of the fixed model of both the CBT and PS groups in each of the eight directions in the bend test are shown in Table 1 and Fig. 5. The mean ROMs in the CBT group ranged from 1.8° to 2.3°, and the mean ROMs in the PS group ranged from 2.2° to 3.2°, indicating that mean ROMs in the CBT group were slightly lesser than those in the PS group. However, there were no significant differences in the mean ROMs between the CBT and PS groups. In all eight directions, the mean rates of relative change of ROMs were slightly lower in the CBT group than in the PS group (Table 2); however, there were no significant differences in the relative change between the two groups.Table 1

Bottom Line: There have been several reports on the pullout strength of cortical bone trajectory (CBT) screws, but only one study has reviewed the stability of functional spine units using the CBT method.The angular displacement from the time of no load to the time of maximum torque was defined as range of motion (ROM), and then, the mean ROM in the bend and rotation tests and the mean rate of relative change of ROM in both the bend and rotation tests were compared between the CBT and PS groups.There were no significant differences between the CBT and PS groups with regard to the mean ROMs and the mean rate of relative change of ROMs in both the bend and rotation tests.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Mie University, Tsu City, Mie, Japan.

ABSTRACT

Purpose: There have been several reports on the pullout strength of cortical bone trajectory (CBT) screws, but only one study has reviewed the stability of functional spine units using the CBT method. The purpose of this study was to compare vertebral stability after CBT fixation with that after pedicle screw (PS) fixation.

Methods: In this study, 20 lumbar spine (L5-6) specimens were assigned to two groups: the CBT model group that underwent CBT screw fixation (n = 10) and the PS model group that underwent pedicle screw fixation (n = 10). Using a six-axis material testing machine, bend and rotation tests were conducted on each model. The angular displacement from the time of no load to the time of maximum torque was defined as range of motion (ROM), and then, the mean ROM in the bend and rotation tests and the mean rate of relative change of ROM in both the bend and rotation tests were compared between the CBT and PS groups.

Results: There were no significant differences between the CBT and PS groups with regard to the mean ROMs and the mean rate of relative change of ROMs in both the bend and rotation tests.

Conclusion: Intervertebral stability after CBT fixation was similar to that after PS fixation.

No MeSH data available.


Related in: MedlinePlus