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Takeuchi T, Takamizawa Y, Konishi K, Sano H, Takahashi M, Kouno H, Hosogane N. Comparison of the Fixation Strengths of Screws between the Traditional Trajectory and the Single and Double Endplate Penetrating Screw Trajectories Using Osteoporotic Vertebral Body Models Based on the Finite Element Method. Asian Spine J 2024; 18:12-20. [PMID: 38379149 PMCID: PMC10910145 DOI: 10.31616/asj.2023.0238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/17/2023] [Accepted: 10/19/2023] [Indexed: 02/22/2024] Open
Abstract
STUDY DESIGN This is a finite element (FE) study. PURPOSE To compare the fixation strength of traditional trajectory (TT) and single and double endplate penetrating screw trajectories (SEPST/DEPST) to the osteoporotic vertebral body model based on the FE method. OVERVIEW OF LITERATURE SEPST/DEPST have been developed to enhance the fixation strength in patients with diffuse idiopathic hyperostosis (DISH). This technique was also applied to patients with osteoporosis. However, determining the superiority of SEPST/ DEPST is difficult because of the heterogeneous patient backgrounds. METHODS Twenty vertebrae (T12 and L1) from 10 patients with osteoporosis (two males and eight females; mean age, 74.7 years) were obtained to create the 10 FE models. First, a single screw was placed with TT and SEPST/DEPST, and the fixation strength was compared by axial pullout strength (POS) and multidirectional loading tests. Second, two screws were placed on the bilateral pedicles with TT and SEPST/DEPST, and the fixation force of the vertebrae in the constructs in flexion, extension, lateral flexion, and axial rotation was examined. RESULTS SEPST and DEPST had 140% and 171% higher POS values than TT, respectively, and the DEPST result was statistically significant (p =0.007). The multidirectional fixation strength was significantly higher in DEPST and SEPST than in TT in the cranial, caudal, and medial directions (p <0.05) but not in the lateral direction (p =0.05). The vertebral fracture strength at the lower instrumented vertebra of the DEPST tended to be higher than that of TT. The vertebral motion angles in SEPST and DEPST were significantly smaller in lateral bending (p =0.02) and tended to be smaller in flexion and extension than in TT (p =0.13). CONCLUSIONS This study may provide useful information for spine surgeons in deciding whether to choose the SEPS or DEPS technique for augmenting fixation in osteoporotic vertebral fracture surgery.
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Affiliation(s)
- Takumi Takeuchi
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, Mitaka,
Japan
| | - Yuhei Takamizawa
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, Mitaka,
Japan
| | - Kazumasa Konishi
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, Mitaka,
Japan
| | - Hideto Sano
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, Mitaka,
Japan
| | - Masahito Takahashi
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, Mitaka,
Japan
| | - Hitoshi Kouno
- Spine Surgery Center, Keiyu Orthopaedic Hospital, Tatebayashi,
Japan
| | - Naobumi Hosogane
- Department of Orthopaedic Surgery, Kyorin University School of Medicine, Mitaka,
Japan
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Saad M, Arfa M, Attia A, Lamas V, Sauleau EA, Charles YP. Proximal and distal mechanical repercussions of instrumentation by double rods and interbody grafts in adult scoliosis. Orthop Traumatol Surg Res 2023; 109:103544. [PMID: 36621636 DOI: 10.1016/j.otsr.2023.103544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/08/2022] [Accepted: 09/22/2022] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Correction of adult scoliosis by instrumentation with double rods and interbody grafts aims to reduce the risk of pseudarthrosis with rod fracture. An increase in instrumentation rigidity can lead to an increase in stresses at the proximal and distal ends of the construct. The aim of this study was to analyze the incidence and clinical repercussions of proximal junctional kyphosis (PJK), proximal junctional failure (PJF) and iliac screw loosening. MATERIEL AND METHODS An analysis of patients operated on for adult scoliosis with instrumentation to the pelvis using 4 rods and interbody cages was carried out from a prospective register. The Visual Analog Scale (VAS), Oswestry Disability Index (ODI), Scoliosis Research Society 22 (SRS-22) clinical scores and radiological parameters were collected preoperatively, postoperatively at 3 months, 1 year and 2 years. The appearance of PJK, PJF or distal screw loosening was sought; the clinical impact and the risk factors were analyzed by Bayesian inference. RESULTS Fifty-one patients with a mean age of 64.5 years were included. The clinical scores improved significantly (Pr>0.95) at 2 years: VAS back 6.9 versus 2.6, VAS leg 4.9 versus 2.5, ODI 48.2 versus 25.4, SRS-22 2.4 versus 3.5. The radiological parameters were corrected (Pr>0.95): Cobb angle 63.9° versus 22.8°, spinosacral angle (SSA) 112.4° versus 118.8°, T1-pelvic angle (TPA) 24, 8° versus 20.8°, lumbar lordosis 43.8° versus 51.0°, thoracic kyphosis 45.2° versus 53.6°. Thirteen patients (25.5%) presented with PJK and 11 (21.6%) with PJF. Seven patients (13.7%) presented with iliac screw loosening. None of these complications was associated with a significant deterioration in clinical scores. Cranial migration of the lumbar apex increased the risk of distal screw loosening: Odds-Ratio 10.31 (Pr>0.999). Two patients were re-operated on for PJF and one patient for iliac screw loosening (5.9%). No rod fracture with pseudarthrosis was found. CONCLUSION Instrumentation with double rods and interbody grafts was associated with a rate of 47.1% of mechanical repercussions at the extremity of the construct. However, these complications were not associated with a significant deterioration in clinical scores. LEVEL OF EVIDENCE III.
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Affiliation(s)
- Maxime Saad
- Service de chirurgie orthopédique et traumatologique, CHU de Grenoble, hôpital Nord, boulevard de la Chantourne, université Grenoble Alpes, 38700 la Tronche, Grenoble, France.
| | - Maher Arfa
- Service de chirurgie du Rachis, hôpitaux universitaires de Strasbourg, faculté de médecine, maïeutique et sciences de la santé, université de Strasbourg, 1, avenue Molière, 67200 Strasbourg, France
| | - Aymen Attia
- Service de chirurgie du Rachis, hôpitaux universitaires de Strasbourg, faculté de médecine, maïeutique et sciences de la santé, université de Strasbourg, 1, avenue Molière, 67200 Strasbourg, France
| | - Vincent Lamas
- Service de chirurgie du Rachis, hôpitaux universitaires de Strasbourg, faculté de médecine, maïeutique et sciences de la santé, université de Strasbourg, 1, avenue Molière, 67200 Strasbourg, France
| | - Erik André Sauleau
- Service de santé publique, hôpitaux universitaires de Strasbourg, faculté de médecine, maïeutique et sciences de la santé, université de Strasbourg, 1, Place de l'hôpital, 67091 Strasbourg cedex, France
| | - Yann Philippe Charles
- Service de chirurgie du Rachis, hôpitaux universitaires de Strasbourg, faculté de médecine, maïeutique et sciences de la santé, université de Strasbourg, 1, avenue Molière, 67200 Strasbourg, France
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Yang H, Li Z, Hai Y, Pan A, Guan L, Liu Y. Comparison of complications, revisions, spinopelvic parameters, and health-related quality of life after posterior spinal fusion using multiple-rod constructs or two-rod constructs for adult spinal deformity: a systematic review and meta-analysis. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2023; 32:3634-3650. [PMID: 37555956 DOI: 10.1007/s00586-023-07876-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/10/2023]
Abstract
BACKGROUND The incidence of mechanical complications is high in patients undergoing posterior spinal fusion (PSF) for adult spinal deformity (ASD), especially for cases with severe sagittal malalignment or a prior spinal fusion requiring three-column osteotomy (3-CO) or spinopelvic fixation (SPF). The purpose of this systematic review and meta-analysis was to compare the complications, revisions, radiographic spinopelvic parameters, health-related quality of life (HRQoL), and surgical data of PSF using multiple-rod constructs to those of two-rod constructs for the treatment of ASD. METHODS A comprehensive literature search was performed for relevant studies in PubMed, EMBASE, Web of Science, and the Cochrane Library. Complications, revisions, spinopelvic parameters, HRQoL, and surgical date were compared between patients with ASD who underwent PSF using multiple-rod constructs (multi-rod group) and two-rod constructs (two-rod group). RESULTS Ten studies, comprising 797 patients with ASD (399 in the multi-rod group and 398 in the two-rod group), were included. All these studies were retrospective cohort studies. There were no significant differences in the surgical, wound-related, and systemic complications between the groups. In the multi-rod group, we noted a significantly lower incidence of rod fracture (RR, 0.43; 95% CI 0.33 to 0.57, P < 0.01), pseudoarthrosis (RR, 0.38; 95% CI 0.28 to 0.53, P < 0.01), and revisions (RR, 0.44; 95% CI 0.33 to 0.58, P < 0.01); a superior restoration of PI-LL (WMD, 3.96; 95% CI 1.03 to 6.88, P < 0.01) and SVA (WMD, 31.53; 95% CI 21.16 to 41.90, P < 0.01); a better improvement of ODI score (WMD, 6.82; 95% CI 2.33 to 11.31, P < 0.01), SRS-22 total score (WMD, 0.44; 95% CI 0.06 to 0.83, P = 0.02), and VAS-BP score (WMD, 1.02; 95% CI 0.31 to 1.73, P < 0.01). CONCLUSION Compared with the two-rod constructs, PSF using multiple-rod constructs was associated with a lower incidence of mechanical complications, a lower revision rate, a superior restoration of sagittal alignment, and a better improvement of HRQoL, without increasing surgical invasiveness. Multiple-rod constructs should be routinely considered to for ASD patients, especially for cases with severe sagittal malalignment or a prior spinal fusion requiring 3-CO or SPF.
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Affiliation(s)
- Honghao Yang
- Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University, Gongti South Rd, No. 8, Beijing, 100020, China
| | - Zhangfu Li
- Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University, Gongti South Rd, No. 8, Beijing, 100020, China
| | - Yong Hai
- Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University, Gongti South Rd, No. 8, Beijing, 100020, China.
| | - Aixing Pan
- Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University, Gongti South Rd, No. 8, Beijing, 100020, China
| | - Li Guan
- Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University, Gongti South Rd, No. 8, Beijing, 100020, China
| | - Yuzeng Liu
- Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University, Gongti South Rd, No. 8, Beijing, 100020, China
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Burkhard MD, Calek AK, Fasser MR, Cornaz F, Widmer J, Spirig JM, Wanivenhaus F, Farshad M. Biomechanics after spinal decompression and posterior instrumentation. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2023; 32:1876-1886. [PMID: 37093262 DOI: 10.1007/s00586-023-07694-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 03/24/2023] [Accepted: 03/28/2023] [Indexed: 04/25/2023]
Abstract
PURPOSE The aim of this study was to elucidate segmental range of motion (ROM) before and after common decompression and fusion procedures on the lumbar spine. METHODS ROM of fourteen fresh-frozen human cadaver lumbar segments (L1/2: 4, L3/4: 5, L5/S1: 5) was evaluated in six loading directions: flexion/extension (FE), lateral bending (LB), lateral shear (LS), anterior shear (AS), axial rotation (AR), and axial compression/distraction (AC). ROM was tested with and without posterior instrumentation under the following conditions: 1) native 2) after unilateral laminotomy, 3) after midline decompression, and 4) after nucleotomy. RESULTS Median native ROM was FE 6.8°, LB 5.6°, and AR 1.7°, AS 1.8 mm, LS 1.4 mm, AC 0.3 mm. Unilateral laminotomy significantly increased ROM by 6% (FE), 3% (LB), 12% (AR), 11% (AS), and 8% (LS). Midline decompression significantly increased these numbers to 15%, 5%, 21%, 20%, and 19%, respectively. Nucleotomy further increased ROM in all directions, most substantially in AC of 153%. Pedicle screw fixation led to ROM decreases of 82% in FE, 72% in LB, 42% in AR, 31% in AS, and 17% in LS. In instrumented segments, decompression only irrelevantly affected ROM. CONCLUSIONS The amount of posterior decompression significantly impacts ROM of the lumbar spine. The here performed biomechanical study allows creation of a simplified rule of thumb: Increases in segmental ROM of approximately 10%, 20%, and 50% can be expected after unilateral laminotomy, midline decompression, and nucleotomy, respectively. Instrumentation decreases ROM by approximately 80% in bending moments and accompanied decompression procedures only minorly destabilize the instrumentation construct.
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Affiliation(s)
- Marco D Burkhard
- Department of Orthopaedic Surgery, University Spine Center Zürich, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
| | - Anna-Katharina Calek
- Department of Orthopaedic Surgery, University Spine Center Zürich, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Marie-Rosa Fasser
- Institute for Biomechanics, Balgrist Campus, ETH Zurich, Lengghalde 5, CH-8008, Zurich, Switzerland
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Frédéric Cornaz
- Department of Orthopaedic Surgery, University Spine Center Zürich, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Jonas Widmer
- Institute for Biomechanics, Balgrist Campus, ETH Zurich, Lengghalde 5, CH-8008, Zurich, Switzerland
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - José Miguel Spirig
- Department of Orthopaedic Surgery, University Spine Center Zürich, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Florian Wanivenhaus
- Department of Orthopaedic Surgery, University Spine Center Zürich, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopaedic Surgery, University Spine Center Zürich, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
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Yang H, Pan A, Hai Y, Cheng F, Ding H, Liu Y. Biomechanical evaluation of multiple pelvic screws and multirod construct for the augmentation of lumbosacral junction in long spinal fusion surgery. Front Bioeng Biotechnol 2023; 11:1148342. [PMID: 36998811 PMCID: PMC10043192 DOI: 10.3389/fbioe.2023.1148342] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/06/2023] [Indexed: 03/15/2023] Open
Abstract
Background: Posterior long spinal fusion was the common procedure for adult spinal deformity (ASD). Although the application of sacropelvic fixation (SPF), the incidence of pseudoarthrosis and implant failure is still high in long spinal fusion extending to lumbosacral junction (LSJ). To address these mechanical complications, advanced SPF technique by multiple pelvic screws or multirod construct has been recommended. This was the first study to compare the biomechanical performance of combining multiple pelvic screws and multirod construct to other advanced SPF constructs for the augmentation of LSJ in long spinal fusion surgery through finite element (FE) analysis.Methods: An intact lumbopelvic FE model based on computed tomography images of a healthy adult male volunteer was constructed and validated. The intact model was modified to develop five instrumented models, all of which had bilateral pedicle screw (PS) fixation from L1 to S1 with posterior lumbar interbody fusion and different SPF constructs, including No-SPF, bilateral single S2-alar-iliac (S2AI) screw and single rod (SS-SR), bilateral multiple S2AI screws and single rod (MS-SR), bilateral single S2AI screw and multiple rods (SS-MR), and bilateral multiple S2AI screws and multiple rods (MS-MR). The range of motion (ROM) and stress on instrumentation, cages, sacrum, and S1 superior endplate (SEP) in flexion (FL), extension (EX), lateral bending (LB), and axial rotation (AR) were compared among models.Results: Compared with intact model and No-SPF, the ROM of global lumbopelvis, LSJ, and sacroiliac joint (SIJ) was decreased in SS-SR, MS-SR, SS-MR, and MS-MR in all directions. Compared with SS-SR, the ROM of global lumbopelvis and LSJ of MS-SR, SS-MR, and MS-MR further decreased, while the ROM of SIJ was only decreased in MS-SR and MS-MR. The stress on instrumentation, cages, S1-SEP, and sacrum decreased in SS-SR, compared with no-SPF. Compared with SS-SR, the stress in EX and AR further decreased in SS-MR and MS-SR. The most significantly decreased ROM and stress were observed in MS-MR.Conclusion: Both multiple pelvic screws and multirod construct could increase the mechanical stability of LSJ and reduce stress on instrumentation, cages, S1-SEP, and sacrum. The MS-MR construct was the most adequate to reduce the risk of lumbosacral pseudarthrosis, implant failure, and sacrum fracture. This study may provide surgeons with important evidence for the application of MS-MR construct in the clinical settings.
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Affiliation(s)
| | | | - Yong Hai
- *Correspondence: Yong Hai, ; Yuzeng Liu,
| | | | | | - Yuzeng Liu
- *Correspondence: Yong Hai, ; Yuzeng Liu,
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Burkhard MD, Spirig JM, Wanivenhaus F, Cornaz F, Fasser MR, Widmer J, Farshad M. Residual motion of different posterior instrumentation and interbody fusion constructs. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2023; 32:1411-1420. [PMID: 36820922 DOI: 10.1007/s00586-023-07597-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/24/2023]
Abstract
PURPOSE To elucidate residual motion of cortical screw (CS) and pedicle screw (PS) constructs with unilateral posterior lumbar interbody fusion (ul-PLIF), bilateral PLIF (bl-PLIF), facet-sparing transforaminal lumbar interbody fusion (fs-TLIF), and facet-resecting TLIF (fr-TLIF). METHODS A total of 35 human cadaver lumbar segments were instrumented with PS (n = 18) and CS (n = 17). Range of motion (ROM) and relative ROM changes were recorded in flexion/extension (FE), lateral bending (LB), axial rotation (AR), lateral shear (LS), anterior shear (AS), and axial compression (AC) in five instrumentational states: without interbody fusion (wo-IF), ul-PLIF, bl-PLIF, fs-TLIF, and fr-TLIF. RESULTS Whereas FE, LB, AR, and AC noticeably differed between the instrumentational states, AS and LS were less prominently affected. Compared to wo-IF, ul-PLIF caused a significant increase in ROM with PS (FE + 42%, LB + 24%, AR + 34%, and AC + 77%), however, such changes were non-significant with CS. ROM was similar between wo-IF and all other interbody fusion techniques. Insertion of a second PLIF (bl-PLIF) significantly decreased ROM with CS (FE -17%, LB -26%, AR -20%, AC -51%) and PS (FE - 23%, LB - 14%, AR - 20%, AC - 45%,). Facet removal in TLIF significantly increased ROM with CS (FE + 6%, LB + 9%, AR + 17%, AC of + 23%) and PS (FE + 7%, AR + 12%, AC + 13%). CONCLUSION bl-PLIF and TLIF show similarly low residual motion in both PS and CS constructs, but ul-PLIF results in increased motion. The fs-TLIF technique is able to further decrease motion compared to fr-TLIF in both the CS and PS constructs.
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Affiliation(s)
- Marco D Burkhard
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
| | - José M Spirig
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Florian Wanivenhaus
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Frédéric Cornaz
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Marie-Rosa Fasser
- Institute for Biomechanics, Balgrist Campus, ETH Zurich, Lengghalde 5, CH-8008, Zurich, Switzerland.,Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jonas Widmer
- Institute for Biomechanics, Balgrist Campus, ETH Zurich, Lengghalde 5, CH-8008, Zurich, Switzerland.,Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
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Pan A, Yang H, Hai Y, Liu Y, Zhang X, Ding H, Li Y, Lu H, Ding Z, Xu Y, Pei B. Adding sacral anchors through an S1 alar screw and multirod construct as a strategy for lumbosacral junction augmentation: an in vitro comparison to S1 pedicle screws alone with sacroiliac fixation. J Neurosurg Spine 2023; 38:107-114. [PMID: 36029265 DOI: 10.3171/2022.6.spine22424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 06/28/2022] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Achieving solid fusion of the lumbosacral junction continues to be a challenge in long-segment instrumentation to the sacrum. The purpose of this study was to test the condition of adding sacral anchors through an S1 alar screw (S1AS) and multirod construct relative to using S1 pedicle screws (S1PSs) alone with sacroiliac fixation in lumbosacral junction augmentation. METHODS Seven fresh-frozen human lumbar-pelvic spine cadaveric specimens were tested under nondestructive moments (7.5 Nm). The ranges of motion (ROMs) in extension, flexion, left and right lateral bending (LB), and axial rotation (AR) of instrumented segments (L3-S1); the lumbosacral region (L5-S1); and the adjacent segment (L2-3) were measured, and the axial construct stiffness (ACS) was recorded. The testing conditions were 1) intact; 2) bilateral pedicle screw (BPS) fixation at L3-S1 (S1PS alone); 3) BPS and unilateral S2 alar iliac screw (U-S2AIS) fixation; 4) BPS and unilateral S1AS (U-S1AS) fixation; 5) BPS and bilateral S2AIS (B-S2AIS) fixation; and 6) BPS and bilateral S1AS (B-S1AS) fixation. Accessory rods were used in testing conditions 3-6. RESULTS In all directions, the ROMs of L5-S1 and L3-S1 were significantly reduced in B-S1AS and B-S2AIS conditions, compared with intact and S1PS alone. There was no significant difference in reduction of the ROMs of L5-S1 between B-S1ASs and B-S2AISs. Greater decreased ROMs of L3-S1 in extension and AR were detected with B-S2AISs than with B-S1ASs. Both B-S1ASs and B-S2AISs significantly increased the ACS compared with S1PSs alone. The ACS of B-S2AISs was significantly greater than that of B-S1ASs, but with greater increased ROMs of L2-3 in extension. CONCLUSIONS Adding sacral anchors through S1ASs and a multirod construct was as effective as sacropelvic fixation in lumbosacral junction augmentation. The ACS was less than the sacropelvic fixation but with lower ROMs of the adjacent segment. The biomechanical effects of using S1ASs in the control of long-instrumented segments were moderate (better than S1PSs alone but worse than sacropelvic fixation). This strategy is appropriate for patients requiring advanced lumbosacral fixation, and the risk of sacroiliac joint violation can be avoided.
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Affiliation(s)
- Aixing Pan
- 1Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University
| | - Honghao Yang
- 1Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University
| | - Yong Hai
- 1Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University
| | - Yuzeng Liu
- 1Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University
| | - Xinuo Zhang
- 1Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University
| | - Hongtao Ding
- 1Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University
| | - Yue Li
- 1Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University
| | - Hongyi Lu
- 1Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University
| | - Zihao Ding
- 1Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University
| | - Yangyang Xu
- 2Beijing Key Laboratory for Design and Evaluation Technology of Advanced Implantable & Interventional Medical Devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Baoqing Pei
- 2Beijing Key Laboratory for Design and Evaluation Technology of Advanced Implantable & Interventional Medical Devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
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Leszczynski A, Meyer F, Charles YP, Deck C, Bourdet N, Willinger R. Influence of double rods and interbody cages on range of motion and rod stress after spinopelvic instrumentation: a finite element study. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2022; 31:1515-1524. [PMID: 35461384 DOI: 10.1007/s00586-022-07149-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 01/05/2022] [Accepted: 02/09/2022] [Indexed: 11/27/2022]
Abstract
PURPOSE To compare instrumentation configurations consisting of bilateral single or double rods and additional interbody cages (IBCs) at different levels in terms of Range of Motion (ROM) and distribution of von Mises stress in rods. METHODS A previously validated L1-pelvis finite element model was used and instrumented with configurations consisting of single or double bilateral rods and IBCs at multiple levels. Pure moments of 7.5 N.m were applied to L1 in main directions in addition to a follower load of 280 N. Global, segmental ROM and distribution of von Mises stress in rods were studied. RESULTS All configurations reduced segmental and global ROM from 50 to 100% compared to the intact spine. Addition of IBCs slightly increased ROM at levels adjacent to the IBC placement. The simple rod configuration presented the highest von Mises stress (457 MPa) in principal rods at L5-S1 in flexion. Doubling rods and IBC placement reduced this value and shifted the location of maximum von Mises stress to other regions. Among studied configurations, double rods with IBCs at all levels (L2-S1) showed the lowest ROM. Maximal von Mises stresses in secondary rods were lower in comparison to main rods. CONCLUSIONS Double rods and IBCs reduced global and segmental ROM as well as von Mises stress in rods. The results suggest a possible benefit in using both strategies to minimize pseudarthrosis and instrumentation failure. However, increased ROM in adjacent levels and the shift of maximal von Mises stress to adjacent areas might cause complications elsewhere.
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Affiliation(s)
- Aleksander Leszczynski
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France.
| | - Frank Meyer
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France
| | - Yann-Philippe Charles
- Service de Chirurgie du Rachis, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Caroline Deck
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France
| | - Nicolas Bourdet
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France
| | - Rémy Willinger
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France
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Leszczynski A, Meyer F, Charles YP, Deck C, Willinger R. Development of a flexible instrumented lumbar spine finite element model and comparison with in-vitro experiments. Comput Methods Biomech Biomed Engin 2021; 25:221-237. [PMID: 34311646 DOI: 10.1080/10255842.2021.1948021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Surgical corrections of degenerative lumbar scoliosis and sagittal malalignment are associated with significant complications, such as rod fractures and pseudarthrosis, particularly in the lumbosacral junction. Finite element studies can provide relevant insights to improve performance of spinal implants. The aim of the present study was to present the development of non-instrumented and instrumented Finite Element Models (FEMs) of the lumbopelvic spine and to compare numerical results with experimental data available in the literature. The lumbo-pelvic spine FEM was based on a CT-scan from an asymptomatic volunteer representing the 50th percentile male. In a first step a calibration of mechanical properties was performed in order to obtain a quantitative agreement between numerical results and experimental data for defect stages of spinal segments. Then, FEM results were compared in terms of range of motion and strains in rods to in-vitro experimental data from the literature for flexible non-instrumented and instrumented lumbar spines. Numerical results from the calibration process were consistent with experimental data, especially in flexion. A positive agreement was obtained between FEM and experimental results for the lumbar and sacroiliac segments. Instrumented FEMs predicted the same trends as experimental in-vitro studies. The instrumentation configuration consisting of double rods and an interbody cage at L5-S1 maximally reduced range of motion and strains in main rods and thus had the lowest risk of pseudarthrosis and rod fracture. The developed FEMs were found to be consistent with published experimental results; therefore they can be used for further post-operative complication investigations.
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Affiliation(s)
| | - Frank Meyer
- ICube, MMB-MechaniCS, University of Strasbourg, Strasbourg, France
| | - Yann-Philippe Charles
- Service de chirurgie du Rachis, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Caroline Deck
- ICube, MMB-MechaniCS, University of Strasbourg, Strasbourg, France
| | - Rémy Willinger
- ICube, MMB-MechaniCS, University of Strasbourg, Strasbourg, France
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Lamas V, Charles YP, Tuzin N, Steib JP. Comparison of degenerative lumbar scoliosis correction and risk for mechanical failure using posterior 2-rod instrumentation versus 4-rod instrumentation and interbody fusion. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2021; 30:1965-1977. [PMID: 33993350 DOI: 10.1007/s00586-021-06870-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 05/02/2021] [Indexed: 01/08/2023]
Abstract
PURPOSE Four-rod instrumentation and interbody fusion may reduce mechanical complications in degenerative scoliosis surgery compared to 2-rod instrumentation. The purpose was to compare clinical results, sagittal alignment and mechanical complications with both techniques. METHODS Full spine radiographs were analysed in 97 patients instrumented to the pelvis: 58 2-rod constructs (2R) and 39 4-rod constructs (4R). Clinical scores (VAS, ODI, SRS-22, EQ-5D-3L) were assessed preoperatively, at 3 months, 1 year and last follow-up (average 4.2 years). Radiographic measurements were: thoracic kyphosis, lumbar lordosis, spinopelvic parameters, segmental lordosis distribution. The incidence of non-union and PJK were investigated. RESULTS All clinical scores improved significantly in both groups between preoperative and last follow-up. In the 2R-group, lumbar lordosis increased to 52.8° postoperatively and decreased to 47.0° at follow-up (p = 0.008). In the 4R-group, lumbar lordosis increased from 46.4 to 52.5° postoperatively and remained at 53.4° at follow-up. There were 8 (13.8%) PJK in the 2R-group versus 6 (15.4%) in the 4R-group, with a mismatch between lumbar apex and theoretic lumbar shape according to pelvic incidence. Non-union requiring revision surgery occurred on average at 26.9 months in 28 patients (48.3%) of the 2R-group. No rod fracture was diagnosed in the 4R-group. CONCLUSION Multi-level interbody fusion combined with 4-rod instrumentation decreased risk for non-union and revision surgery compared to select interbody fusion and 2-rod instrumentation. The role of additional rods on load sharing still needs to be determined when multiple cages are used. Despite revision surgery in the 2R group, final clinical outcomes were similar in both groups. LEVEL OF EVIDENCE III.
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Affiliation(s)
- Vincent Lamas
- Service de Chirurgie du Rachis, Hôpitaux Universitaires de Strasbourg, Fédération de Médecine Translationnelle (FMTS), Université de Strasbourg, 1 Avenue Molière, 67200, Strasbourg, France.
| | - Yann Philippe Charles
- Service de Chirurgie du Rachis, Hôpitaux Universitaires de Strasbourg, Fédération de Médecine Translationnelle (FMTS), Université de Strasbourg, 1 Avenue Molière, 67200, Strasbourg, France
| | - Nicolas Tuzin
- Service de Santé Publique, Hôpitaux Universitaires de Strasbourg, Fédération de Médecine Translationnelle (FMTS), Université de Strasbourg, Strasbourg, France
| | - Jean-Paul Steib
- Service de Chirurgie du Rachis, Hôpitaux Universitaires de Strasbourg, Fédération de Médecine Translationnelle (FMTS), Université de Strasbourg, 1 Avenue Molière, 67200, Strasbourg, France
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