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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, Polly DW, Lindsey DP, Villa TMT, Yerby SA, Brayda-Bruno M, Galbusera F. Effect of Sacropelvic Hardware on Axis and Center of Rotation of the Sacroiliac Joint: A Finite Element Study. Int J Spine Surg 2023; 17:122-131. [PMID: 36574987 PMCID: PMC10025848 DOI: 10.14444/8387] [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: 12/28/2022] Open
Abstract
BACKGROUND The sacroiliac joint (SIJ) transfers the load of the upper body to the lower extremities while allowing a variable physiological movement among individuals. The axis of rotation (AoR) and center of rotation (CoR) of the SIJ can be evaluated to analyze the stability of the SIJ, including when the sacrum is fixed. The purpose of this study was to determine how load intensity affects the SIJ for the intact model and to characterize how sacropelvic fixation performed with different techniques affects this joint. METHODS Five T10-pelvis models were used: (1) intact model; (2) pedicle screws and rods in T10-S1; (3)pedicle screws and rods in T10-S1, and bilateral S2 alar-iliac screws (S2AI); (4) pedicle screws and rods in T10-S1, bilateral S2AI screws, and triangular implants inserted bilaterally in a sacral alar-iliac trajectory ; and (5) pedicle screws and rods in T10-S1, bilateral S2AI screws, and 2 bilateral triangular implants inserted in a lateral trajectory. Outputs of these models under flexion-extension were compared: AoR and CoR of the SIJ at incremental steps from 0 to 7.5 Nm for the intact model and AoR and CoR of the SIJ for the instrumented models at 7.5 Nm. RESULTS The intact model was validated against an in vivo study by comparing range of motion and displacement of the sacrum. Increasing the load intensity for the intact model led to an increase of the rotation of the sacrum but did not change the CoR. Comparison among the instrumented models showed that sacropelvic fixation techniques reduced the rotation of the sacrum and stabilized the SIJ, in particular with triangular implants. CONCLUSION The study outcomes suggest that increasing load intensity increases the rotation of the sacrum but does not influence the CoR, and use of sacropelvic fixation increases the stability of the SIJ, especially when triangular implants are employed. CLINICAL RELEVANCE The choice of the instrumentation strategy for sacropelvic fixation affects the stability of the construct in terms of both range of motion and axes of rotation, with direct consequences on the risk of failure and mobilization. Clinical studies should be performed to confirm these biomechanical findings.
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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
| | | | - David W Polly
- Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, USA
| | | | - Tomaso M T 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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Hirase T, Shin C, Ling J, Phelps B, Haghshenas V, Saifi C, Hanson DS. S2 alar-iliac screw versus traditional iliac screw for spinopelvic fixation: a systematic review of comparative biomechanical studies. Spine Deform 2022; 10:1279-88. [PMID: 35763199 DOI: 10.1007/s43390-022-00528-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/20/2022] [Indexed: 10/17/2022]
Abstract
PURPOSE To review and compare biomechanical properties between S2 alar-iliac (S2AI) screws and traditional iliac screws for spinopelvic fixation. METHODS A systematic review was performed according to PRISMA guidelines. All clinical, cadaveric, and finite-element model (FEM) studies that compared the biomechanical properties between S2AI screws and traditional iliac screws were included. Study methodological quality for cadaveric studies were analyzed using the Quality Appraisal for Cadaveric Studies (QUACS) scale. RESULTS Eight studies (4 cadaveric, 4 FEM) analyzing 58 S2AI screws and 48 traditional iliac screws were included. According to QUACS, the overall methodological quality was "moderate to good" for all four cadaveric studies. All four cadaveric studies found no difference in biomechanical stiffness, screw toggle, rod strain, and/or load-to-failure between the S2AI screws and traditional iliac screws for spinopelvic fixation. All four FEM studies found that S2AI screws were associated with lower implant stresses compared to traditional iliac screws. CONCLUSIONS There is moderate biomechanical evidence to suggest that there is no significant difference in stability and stiffness between S2AI screws and traditional iliac screws for spinopelvic fixation. However, there is some evidence to support that the placement of S2AI screws may have lower implant stresses on the overall lumbosacral instrumentation compared to traditional iliac screws.
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Luo Y, Li Y, He L, Yin E, Gu M, Xu Z, Chen H, Hou Z, Yi C. Lumbopelvic fixation with S2 alar-iliac screws for U-shaped sacral fractures. Injury 2022; 54 Suppl 2:S8-S14. [PMID: 35180997 DOI: 10.1016/j.injury.2022.02.022] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 01/10/2022] [Accepted: 02/06/2022] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate the surgical methods and clinical effects of lumbopelvic fixation (LPF) with S2 alar-iliac (S2AI) screws for U-shaped sacral fractures. METHODS From December 2019 to August 2020, 14 patients with U-shaped sacral fractures were treated with LPF using S2AI screws. Demographics, fracture classification, mechanism of injury, surgical treatment, complications and clinical results were assessed. All patients had a LPF with or without nerve decompression. The reduction quality was evaluated according to the Matta criteria. Neurological function was evaluated according to the Gibbons grading. The activities of daily life were evaluated according to the Majeed scoring system at the last follow-up. RESULTS Among 14 consecutive patients with U-shaped sacral fractures, the age at injury ranged from 13 to 72 years (average 30.3 ± 17.5 years). There were 4 males and 10 females. All patients were followed up for 6-15 months (average 7.8 ± 2.7 months). Thirteen patients were fixed with bilateral S2AI screws, and one patient was fixed only unilaterally due to unilateral spinopelvic dissociation. The excellent and good rate of postoperative pelvic reduction quality was 92% (excellent 10, good 3, fair 1). At the latest follow-up, the excellent and good rate of pelvic function was 100% (excellent 9, good 5) and all patients achieved different extents of neurological recovery. One patient had a postoperative superficial surgical site infection, which healed after debridement. Radiological examination at 3-6 months after operation showed that all fractures had healed. No complications were found in any patients during follow-up, such as implant fracture, loss of reduction, deep wound infection, wound dehiscence and screw protrusion discomfort. CONCLUSION LPF with S2AI screws for the treatment of U-shaped sacral fractures has exhibited distinct advantages, including firm fixation, a low rate of surgical site complications and satisfactory clinical efficacy. This approach provides sufficient stability to accelerate the commencement of postoperative rehabilitation.
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Affiliation(s)
- Yangxing Luo
- Department of Traumatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yue Li
- Department of Traumatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Li He
- Department of Traumatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Enzhi Yin
- Department of Traumatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Meiqi Gu
- Department of Traumatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhe Xu
- Department of Traumatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Hua Chen
- Department of Orthopaedic Trauma, Chinese PLA General Hospital (301 Hospital), Beijing 100853, China
| | - Zhiyong Hou
- Department of Orthopaedic Surgery, Third Hospital of Hebei Medical University, Shijiazhuang 050051, China
| | - Chengla Yi
- Department of Traumatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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Zhou Z, Tu C, Yu H, Xiong J, Liu Z, Ma S, Deng W, Cao K. Ball Tip Technique for S2AI Screw Placement in Sacropelvic Fixation: A Comparative Study with Conventional Freehand Technique. Orthop Surg 2022; 14:389-396. [PMID: 34978154 PMCID: PMC8867419 DOI: 10.1111/os.13196] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/22/2021] [Accepted: 11/22/2021] [Indexed: 12/01/2022] Open
Abstract
Objective To evaluate the efficiency of the ball tip technique for S2AI screw placement and introduce this technique. Methods Sixty‐three patients who underwent pelvic fixation with S2AI screws were retrospectively reviewed. They were 29 males and 34 females with an average age of 59.6 ± 12.5 years. Among these patients, 35 patients (14 males and 21 females with an average age of 58.8 ± 11.3 years) received ball tip technique and 28 patients (15 males and 13 females with an average age of 63.7 ± 12.6 years) received conventional freehand technique. Ball tip technique was used in ball tip technique group. After a pedicle probe just penetrated the sacroiliac joint, a ball‐tipped probe consisting of a ball shaped metal tip with a flexible shaft was malleted to make a guide track within ilium. This ball‐tipped probe could bend automatically away from the cortex and forward through the cancellous bone when the tip met the cortical lamina of ilium, which can avoid penetration. After repeating the procedures, a guide hole was gradually formed. S2AI screw was inserted along the guide hole after tapping. In the conventional freehand group, S2AI screw was placed according to the conventional method. Postoperative computed tomography (CT) was used to assess the accuracy of screws. The time cost of screw insertion and screw‐related complications were recorded. Independent t‐test was used to compare the time cost between ball tip group and conventional freehand group. A chi‐square test was used to compare the accuracies of the ball tip group with the conventional group. Results There were 35 patients (70 S2AI screws) in ball tip group and 28 patients (56 S2AI screws) in conventional freehand group. No screw‐related complication occurred in all patients. Time costs were 9.8 ± 4.5 mins in ball tip group and 20.2.0 + 8.6 mins in conventional freehand group, respectively (P < 0.05). Four screws penetrated iliac cortex in the ball tip group vs 10 screws in conventional freehand group (5.7% vs 17.9%) (P < 0.05). Conclusions The ball tip technique enhances the accuracy of screw placement and has less time cost compared with conventional freehand technique.
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Affiliation(s)
- Zhenhai Zhou
- The Orthopaedic Hospital, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Cheng Tu
- Lushan Convalescent Center and Clinic of People's Liberation Army of China, Jiujiang, China
| | - Honggui Yu
- The Orthopaedic Hospital, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jiachao Xiong
- The Orthopaedic Hospital, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Zhiming Liu
- The Orthopaedic Hospital, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Shengbiao Ma
- The Orthopaedic Hospital, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Wenqiang Deng
- The Orthopaedic Hospital, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Kai Cao
- The Orthopaedic Hospital, The First Affiliated Hospital of Nanchang University, Nanchang, China
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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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Von Glinski A, Pierre C, Frieler S, Mahoney JM, Harris JA, Amin DB, Allall M, Bucklen BS, Schildhauer TA, Oskouian RJ, Chapman JR. Fixation Strength of Modified Iliac Screw Trajectory Compared to Traditional Iliac and S2 Alar-Iliac Trajectories: A Cadaveric Study. World Neurosurg 2021; 154:e481-e487. [PMID: 34298135 DOI: 10.1016/j.wneu.2021.07.065] [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] [Received: 05/28/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Traditional iliac (TI) screws require extensive dissection, involve offset-connectors, and have prominent screw heads that may cause patient discomfort. S2 alar-iliac (S2AI) screws require less dissection, do not need offset connectors, and are less prominent. However, the biomechanical consequences of S2AI screws crossing the alar-iliac joint is unknown. The present study investigates the fixation strength of a modified iliac (MI) screw, which has a more medial entry point and reduced screw prominence, but does not cross the alar-iliac joint. METHODS Eighteen sacropelvic spines were divided into 3 groups (n = 6): TI, S2AI, and MI. Each specimen was fixed unilaterally with S1 pedicle screws and pelvic fixation according to its group. Screws were loaded at ±10 Nm at 3Hz for 1000 cycles. Motion of each screw and rod strain above and below the S1 screw was measured. RESULTS Toggle of the S1 screw was lowest for the TI group, followed by the MI and S2AI groups, but there were no significant differences (P = 0.421). Toggle of the iliac screw relative to the pelvis was also lowest for the TI group, followed by the MI group, and was greatest for the S2AI group, without significant differences (P = 0.179). Rod strain was similar across all groups. CONCLUSIONS No statistically significant differences were found between the TI, S2AI, and MI techniques with regard to screw toggle or rod strain. Advantages of the MI screw include its lower profile and a medialized starting point eliminating the need for offset-connectors.
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Affiliation(s)
- Alexander Von Glinski
- Swedish Neuroscience Institute, Swedish Medical Center, Seattle, Washington, USA; University Hospital Bergmannsheil, Bochum, Germany.
| | - Clifford Pierre
- Swedish Neuroscience Institute, Swedish Medical Center, Seattle, Washington, USA
| | - Sven Frieler
- Swedish Neuroscience Institute, Swedish Medical Center, Seattle, Washington, USA
| | - Jonathan M Mahoney
- Musculoskeletal Education and Research Center, A Division of Globus Medical Inc., Audubon, Pennsylvania, USA
| | - Jonathan A Harris
- Musculoskeletal Education and Research Center, A Division of Globus Medical Inc., Audubon, Pennsylvania, USA
| | - Dhara B Amin
- Musculoskeletal Education and Research Center, A Division of Globus Medical Inc., Audubon, Pennsylvania, USA
| | - May Allall
- College of Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Brandon S Bucklen
- Musculoskeletal Education and Research Center, A Division of Globus Medical Inc., Audubon, Pennsylvania, USA
| | | | - Rod J Oskouian
- Swedish Neuroscience Institute, Swedish Medical Center, Seattle, Washington, USA
| | - Jens R Chapman
- Swedish Neuroscience Institute, Swedish Medical Center, Seattle, Washington, USA
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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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Nazemi AK, Gowd AK, Vaccaro AR, Carmouche JJ, Behrend CJ. Unilateral S2 alar-iliac screws for spinopelvic fixation. Surg Neurol Int 2018; 9:75. [PMID: 29721354 PMCID: PMC5909091 DOI: 10.4103/sni.sni_460_17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/26/2018] [Indexed: 11/16/2022] Open
Abstract
Background: This study compared the clinical complications, radiographic measurements of deformity, and quality of life outcomes for patients with de novo scoliosis undergoing thoracolumbar fusions for spinopelvic fixation (SPF) utilizing unilateral S2 alar-iliac (S2AI) screw or unilateral iliac bolt fixation. Methods: This retrospective review was performed in 29 patients who underwent SPF at one institution; 10 patients received unilateral S2AI screws, and 19 patients received unilateral iliac bolts. The following variables were studied: reoperation rates, pseudarthrosis, sacral insufficiency fracture, hardware prominence, infection, proximal junctional kyphosis (PJK), deformity correction (radiographs), windshield wipering, hardware fracture, and hardware removal. Outcomes were analyzed utilizing both the visual analog scale (VAS) and Oswestry Disability Index (ODI). The mean follow-up period was 27 months. Results: The reoperation rate for unilateral S2AI screws was 30% vs. 53% for unilateral iliac bolts (P = 0.43); reoperations were performed with a 1:5 ratio for infection, a 1:4 ratio for pseudarthrosis, and 1:1 a ratio for PJK comparing S2AI screws to iliac bolts, respectively. Conclusion: There were no significant differences in postoperative complications and reoperation rates between unilateral S2AI screws and unilateral iliac bolts utilized for SPF. For the S2AI screw group, there were no instances of hardware prominence or need for removal. The use of unilateral S2AI screws resulted in adequate fixation and comparably low complication rates.
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Affiliation(s)
- Alireza K Nazemi
- Virginia Tech Carilion School of Medicine, Riverside Circle, Roanoke, Virginia, USA.,Institute for Orthopedics and Neurosciences, Carilion Clinic, Roanoke, Virginia, USA
| | - Anirudh K Gowd
- Virginia Tech Carilion School of Medicine, Riverside Circle, Roanoke, Virginia, USA.,Institute for Orthopedics and Neurosciences, Carilion Clinic, Roanoke, Virginia, USA
| | | | - Jonathan J Carmouche
- Virginia Tech Carilion School of Medicine, Riverside Circle, Roanoke, Virginia, USA.,Institute for Orthopedics and Neurosciences, Carilion Clinic, Roanoke, Virginia, USA
| | - Caleb J Behrend
- Virginia Tech Carilion School of Medicine, Riverside Circle, Roanoke, Virginia, USA.,Institute for Orthopedics and Neurosciences, Carilion Clinic, Roanoke, Virginia, USA
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