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Panico M, Chande RD, Lindsey DP, Mesiwala A, Polly DW, Villa T, Yerby SA, Brayda-Bruno M, Galbusera F. Stability and Instrumentation Stresses Among Sacropelvic Fixation Techniques With Novel Porous Fusion/Fixation Implants: A Finite Element Study. Int J Spine Surg 2023; 17:598-606. [PMID: 37460239 PMCID: PMC10478686 DOI: 10.14444/8481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2023] Open
Abstract
BACKGROUND Sacropelvic fixation is frequently combined with thoracolumbar instrumentation for correcting spinal deformities. This study aimed to characterize sacropelvic fixation techniques using novel porous fusion/fixation implants (PFFI). METHODS Three T10-pelvis finite element models were created: (1) pedicle screws and rods in T10-S1, PFFI bilaterally in S2 alar-iliac (S2AI) trajectory; (2) fixation in T10-S1, PFFI bilaterally in S2AI trajectory, triangular implants bilaterally above the PFFI in a sacro-alar-iliac trajectory (PFFI-IFSAI); and (3) fixation in T10-S1, PFFI bilaterally in S2AI trajectory, PFFI in sacro-alar-iliac trajectory stacked cephalad to those in S2AI position (2-PFFI). Models were loaded with pure moments of 7.5 Nm in flexion-extension, lateral bending, and axial rotation. Outputs were compared against 2 baseline models: (1) pedicle screws and rods in T10-S1 (PED), and (2) pedicle screws and rods in T10-S1, and S2AI screws. RESULTS PFFI and S2AI resulted in similar L5-S1 motion; adding another PFFI per side (2-PFFI) further reduced this motion. Sacroiliac joint (SIJ) motion was also similar between PFFI and S2AI; PFFI-IFSAI and 2-PFFI demonstrated a further reduction in SIJ motion. Additionally, PFFI reduced max stresses on S1 pedicle screws and on implants in the S2AI position. CONCLUSION The study shows that supplementing a long construct with PFFI increases the stability of the L5-S1 and SIJ and reduces stresses on the S1 pedicle screws and implants in the S2AI position. CLINICAL RELEVANCE The findings suggest a reduced risk of pseudarthrosis at L5-S1 and screw breakage. Clinical studies may be performed to demonstrate applicability to patient outcomes. LEVEL OF EVIDENCE Not applicable (basic science study).
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Affiliation(s)
- Matteo Panico
- IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | | | | | - Ali Mesiwala
- DISC Sports and Spine Center, Newport Beach, CA, USA
| | - David W Polly
- Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, USA
| | - Tomaso Villa
- IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
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Panico M, Chande RD, Lindsey DP, Mesiwala A, Villa TMT, Yerby SA, Gallazzi E, Brayda-Bruno M, Galbusera F. Innovative sacropelvic fixation using iliac screws and triangular titanium implants. Eur Spine J 2021; 30:3763-3770. [PMID: 34562177 DOI: 10.1007/s00586-021-07006-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/19/2021] [Accepted: 09/21/2021] [Indexed: 11/29/2022]
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.
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Affiliation(s)
- Matteo Panico
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, 20133, Milan, Italy. .,IRCCS Istituto Ortopedico Galeazzi, Milan, Italy.
| | | | | | - Ali Mesiwala
- Southern California Center for Neuroscience and Spine, Pomona, CA, USA
| | - Tomaso Maria Tobia Villa
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, 20133, Milan, Italy.,IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | | | - Enrico Gallazzi
- ASST Gaetano Pini: Azienda Socio Sanitaria Territoriale Gaetano Pini, Milan, Italy
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Panico M, Chande RD, Lindsey DP, Mesiwala A, Villa TMT, Yerby SA, Brayda-Bruno M, Galbusera F. The use of triangular implants to enhance sacropelvic fixation: a finite element investigation. Spine J 2020; 20:1717-1724. [PMID: 32502655 DOI: 10.1016/j.spinee.2020.05.552] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 05/21/2020] [Accepted: 05/21/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Long thoracolumbar fixation and fusion have become a consolidated treatment for severe spinal disorders. Concomitant sacropelvic fixation with S2 alar-iliac (S2AI) screws is frequently performed to limit instrumentation failure and pseudarthrosis at the lumbosacral junction. PURPOSE This study explored the use of triangular titanium implants in different configurations in which the implants supplemented standard sacropelvic fixation with S2AI screws in order to further increase the stability of S2AI fixation. STUDY DESIGN Finite element study. METHODS Four T10-pelvis instrumented models were built: pedicle screws and rods in T10-S1 (PED); pedicle screws and rods in T10-S1, and bilateral S2 alar-iliac screws (S2AI); pedicle screws and rods in T10-S1, bilateral S2AI screws, and triangular implants inserted bilaterally in a sacral alar-iliac trajectory (Tri-SAI); pedicle screws and rods in T10-S1, bilateral S2AI screws and two bilateral triangular titanium implants inserted in a lateral trajectory (Tri-Lat). The models were tested under pure moments of 7.5 Nm in flexion-extension, lateral bending and axial rotation. RESULTS SIJ motion was reduced by 50% to 66% after S2AI fixation; the addition of triangular titanium implants in either a SAI or a lateral trajectory further reduced it. S2AI, Tri-SAI, and Tri-Lat resulted in significantly lower stresses in S1 pedicle screws when compared to PED. Triangular implants had a protective effect on the maximal stresses in S2AI screws, especially when placed in the SAI trajectory. Sacropelvic fixation did not have any protective effect on the posterior rods. CONCLUSIONS Supplementing S2AI screws with triangular implants had a protective effect on the S2AI screws themselves, as well as the S1 pedicle screws, in the tested model. CLINICAL SIGNIFICANCE Triangular implants can substantially reduce the residual flexibility of the SIJ with respect to S2AI fixation alone, suggesting a possible role in patients needing reinforced fixation. In vivo investigation is needed to determine if these in vitro effects translate into clinically important differences.
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Affiliation(s)
- Matteo Panico
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy; IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | | | | | - Ali Mesiwala
- Southern California Center for Neuroscience and Spine, Pomona, CA, USA
| | - Tomaso Maria Tobia Villa
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
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Galbusera F, Casaroli G, Chande R, Lindsey D, Villa T, Yerby S, Mesiwala A, Panico M, Gallazzi E, Brayda-Bruno M. Biomechanics of sacropelvic fixation: a comprehensive finite element comparison of three techniques. Eur Spine J 2019; 29:295-305. [PMID: 31773275 DOI: 10.1007/s00586-019-06225-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 10/09/2019] [Accepted: 11/16/2019] [Indexed: 02/26/2023]
Abstract
PURPOSE Sacropelvic fixation is frequently used in combination with thoracolumbar instrumentation for complex deformity correction and is commonly associated with pseudoarthrosis, implant failure and loosening. This study compared pedicle screw fixation (PED) with three different sacropelvic fixation techniques, namely iliac screws (IL), S2 alar-iliac screws (S2AI) and laterally placed triangular titanium implants (SI), all in combination with lumbosacral instrumentation, accounting for implant micromotion. METHODS Existing finite element models of pelvis-L5 of three patients including lumbopelvic instrumentation were utilized. Moments of 7.5 Nm in the three directions combined with a 500 N compressive load were simulated. Measured metrics included flexibility, instrumentation stresses and bone-implant interface loads. RESULTS Fixation effectively reduced the sacroiliac flexibility. Compared to PED, IL and S2AI induced a reduction in peak stresses in the S1 pedicle screws. Rod stresses were mostly unaffected by S2AI and SI, but IL demonstrated a stress increase. In comparison with a previous work depicting full osteointegration, SI was found to have similar instrumentation stresses as those due to PED. CONCLUSIONS Fixation with triangular implants did not result in stress increase on the lumbosacral instrumentation, likely due to the lack of connection with the posterior rods. IL and S2AI had a mild protective effect on S1 pedicle screws in terms of stresses and bone-implant loads. IL resulted in an increase in the rod stresses. A comparison between this study and previous work incorporating full osteointegration demonstrates how these results may be applied clinically to better understand the effects of different treatments on patient outcomes. These slides can be retrieved under Electronic Supplementary Material.
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Affiliation(s)
- Fabio Galbusera
- Laboratory of Biological Structures Mechanics, IRCCS Istituto Ortopedico Galeazzi, via Galeazzi 4, 20161, Milan, Italy.
| | - Gloria Casaroli
- Laboratory of Biological Structures Mechanics, IRCCS Istituto Ortopedico Galeazzi, via Galeazzi 4, 20161, Milan, Italy
| | | | | | - Tomaso Villa
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico Di Milano, Milan, Italy
| | | | - Ali Mesiwala
- Southern California Center for Neuroscience and Spine, Pomona, CA, USA
| | - Matteo Panico
- Laboratory of Biological Structures Mechanics, IRCCS Istituto Ortopedico Galeazzi, via Galeazzi 4, 20161, Milan, Italy.,Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico Di Milano, Milan, Italy
| | - Enrico Gallazzi
- Laboratory of Biological Structures Mechanics, IRCCS Istituto Ortopedico Galeazzi, via Galeazzi 4, 20161, Milan, Italy
| | - Marco Brayda-Bruno
- Laboratory of Biological Structures Mechanics, IRCCS Istituto Ortopedico Galeazzi, via Galeazzi 4, 20161, Milan, Italy
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