Matteo Panico1,2, Ruchi D Chande3, Derek P Lindsey3, Ali Mesiwala4, Tomaso Maria Tobia Villa5,6, Scott A Yerby3, Enrico Gallazzi7, Marco Brayda-Bruno6, Fabio Galbusera6. 1. Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, 20133, Milan, Italy. matteo.panico@polimi.it. 2. IRCCS Istituto Ortopedico Galeazzi, Milan, Italy. matteo.panico@polimi.it. 3. SI-BONE, Inc., Santa Clara, CA, USA. 4. Southern California Center for Neuroscience and Spine, Pomona, CA, USA. 5. Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, 20133, Milan, Italy. 6. IRCCS Istituto Ortopedico Galeazzi, Milan, Italy. 7. ASST Gaetano Pini: Azienda Socio Sanitaria Territoriale Gaetano Pini, Milan, Italy.
Abstract
PURPOSE: Sacropelvic fixation is frequently used in combination with thoracolumbar instrumentation for the correction of severe spinal deformities. The purpose of this study was to explore the effects of the triangular titanium implants on the iliac screw fixation. Our hypothesis was that the use of triangular titanium implants can increase the stability of the iliac screw fixation. METHODS: Three T10-pelvis instrumented models were created: pedicle screws and rods in T10-S1, and bilateral iliac screws (IL); posterior fixation and bilateral iliac screws and triangular implants inserted bilaterally in a sacro-alar-iliac trajectory (IL-Tri-SAI); posterior fixation and bilateral iliac screws and two bilateral triangular titanium implants inserted in a lateral trajectory (IL-Tri-Lat). Outputs of these models, such as hardware stresses, were compared against a model with pedicle screws and rods in T10-S1 (PED). RESULTS: Sacropelvic fixation decreased the L5-S1 motion by 75-90%. The motion of the SIJ was reduced by 55-80% after iliac fixation; the addition of triangular titanium implants further reduced it. IL, IL-Tri-SAI and IL-Tri-Lat demonstrated lower S1 pedicle stresses with respect to PED. Triangular implants had a protective effect on the iliac screw stresses. CONCLUSION: Sacropelvic fixation decreased L5-S1 range of motion suggesting increased stability of the joint. The combination of triangular titanium implants and iliac screws reduced the residual flexibility of the sacroiliac joint, and resulted in a protective effect on the S1 pedicle screws and iliac screws themselves. Clinical studies may be performed to demonstrate applicability of these FEA results to patient outcomes.
PURPOSE: Sacropelvic fixation is frequently used in combination with thoracolumbar instrumentation for the correction of severe spinal deformities. The purpose of this study was to explore the effects of the triangular titanium implants on the iliac screw fixation. Our hypothesis was that the use of triangular titanium implants can increase the stability of the iliac screw fixation. METHODS: Three T10-pelvis instrumented models were created: pedicle screws and rods in T10-S1, and bilateral iliac screws (IL); posterior fixation and bilateral iliac screws and triangular implants inserted bilaterally in a sacro-alar-iliac trajectory (IL-Tri-SAI); posterior fixation and bilateral iliac screws and two bilateral triangular titanium implants inserted in a lateral trajectory (IL-Tri-Lat). Outputs of these models, such as hardware stresses, were compared against a model with pedicle screws and rods in T10-S1 (PED). RESULTS: Sacropelvic fixation decreased the L5-S1 motion by 75-90%. The motion of the SIJ was reduced by 55-80% after iliac fixation; the addition of triangular titanium implants further reduced it. IL, IL-Tri-SAI and IL-Tri-Lat demonstrated lower S1 pedicle stresses with respect to PED. Triangular implants had a protective effect on the iliac screw stresses. CONCLUSION: Sacropelvic fixation decreased L5-S1 range of motion suggesting increased stability of the joint. The combination of triangular titanium implants and iliac screws reduced the residual flexibility of the sacroiliac joint, and resulted in a protective effect on the S1 pedicle screws and iliac screws themselves. Clinical studies may be performed to demonstrate applicability of these FEA results to patient outcomes.
Authors: Gary D Fleischer; Yongjung J Kim; Lisa A Ferrara; Andrew L Freeman; Oheneba Boachie-Adjei Journal: Spine (Phila Pa 1976) Date: 2012-02-01 Impact factor: 3.468
Authors: Christopher J Kleck; Damian Illing; Emily M Lindley; Andriy Noshchenko; Vikas V Patel; Cameron Barton; Todd Baldini; Christopher M J Cain; Evalina L Burger Journal: Spine Deform Date: 2017-01
Authors: Woojin Cho; Jonathan R Mason; Justin S Smith; Adam L Shimer; Adam S Wilson; Christopher I Shaffrey; Francis H Shen; Wendy M Novicoff; Kai-Ming G Fu; Joshua E Heller; Vincent Arlet Journal: J Neurosurg Spine Date: 2013-08-02