Biomechanical study on thoracic spine segment fixed by pedicle screws placed with “funnel technique”
- VernacularTitle:采用“漏斗技术”植入椎弓根螺钉固定胸段脊柱的生物力学研究
- Author:
Liang-le LIU
1
;
Cheng-xuan TANG
1
;
Guo-jing YANG
1
;
Li-chen ZHANG
1
;
Cheng-lin LU
2
,
3
;
Dong-sheng ZHANG
2
,
3
;
Ke-ping PAN
1
Author Information
1. Department of Orthopedics and Spine Surgery, the third Affiliated Hospital of Wenzhou Medical College
2. Department of Mechanics, Shanghai University
3. Shanghai Institute of Applied Mathematics and Mechanics
- Publication Type:Journal Article
- Keywords:
Thoracic spine;
Pedicle screws;
Biomechanical properties;
Funnel technique
- From:
Journal of Medical Biomechanics
2010;25(2):E089-E093
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate mechanical properties of the thoracic spine fixed with pedicle screws that were placed using a “funnel technique”. MethodFourteen thoracic spinal segments (T6 to T10) were collected from adult cadavers. These specimens were divided into two groups, 7 in each, and fixed with pedicle screw using funnel and Magerl techniques. The displacement stiffness of the spinal segment and the pull out strength of the pedicle screw were tested for intact and fixed spinal specimens. The displacement stiffness was measured from different loading directions, including axial compression, anterior flexion, posterior extension, lateral bending and axial torsion. ResultsCompared to the intact spine segments, the displacement stiffness is significantly increased (P＜0.05) at all directions in the segments fixed with either funnel or Magerl technique; however, there is no significant difference between the groups fixed with different technique. The screw pull out strength is significantly decreased (P＜0.05) in spine segments fixed with Funnel technique compared to those fixed with Magerl technique. ConclusionsSince funnel technique removed a portion of bone from the posterior side of the vertebral pedicle, it can raise the accuracy and safety for the placement of pedicle screw. Although this technique does not affect the stiffness of fixed spinal segment, it may decrease the anchor strength of pedicle screw. Accordingly, we recommend that the funnel technique can be considered as a complement method for the fixation of vertebral fracture using pedicle screws.
