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Agaronnik ND, Giberson-Chen C, Bono CM. Using advanced imaging to measure bone density, compression fracture risk, and risk for construct failure after spine surgery. Spine J 2024:S1529-9430(24)00103-7. [PMID: 38437918 DOI: 10.1016/j.spinee.2024.02.018] [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: 07/04/2023] [Revised: 01/22/2024] [Accepted: 02/23/2024] [Indexed: 03/06/2024]
Abstract
Low bone mineral density (BMD) can predispose to vertebral body compression fractures and postoperative instrumentation failure. DEXA is considered the gold standard for measurement of BMD, however it is not obtained for all spine surgery patients preoperatively. There is a growing body of evidence suggesting that more routinely acquired spine imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI) can be opportunistically used to measure BMD. Here we review available studies that assess the validity of opportunistic screening with CT-derived Hounsfield Units (HU) and MRI-derived vertebral vone quality (VBQ) to measure BMD of the spine as well the utility of these measures in predicting post-operative outcomes. Additionally, we provide screening thresholds based on HU and VBQ for prediction of osteopenia/ osteoporosis and post-operative outcomes such as cage subsidence, screw loosening, proximal junctional kyphosis, and implant failure.
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Affiliation(s)
| | - Carew Giberson-Chen
- Harvard Combined Orthopaedic Residency Program, 55 Fruit Street, Yawkey Building, Suite 3A, Boston, MA 02114
| | - Christopher M Bono
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115; Harvard Combined Orthopaedic Residency Program, 55 Fruit Street, Yawkey Building, Suite 3A, Boston, MA 02114; Department of Orthopaedic Surgery, Massachusetts General Hospital, 55 Fruit Street, Yawkey Building, Suite 3A, Boston, MA 02114.
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Tsagkaris C, Calek AK, Fasser MR, Spirig JM, Caprara S, Farshad M, Widmer J. Bone density optimized pedicle screw insertion. Front Bioeng Biotechnol 2023; 11:1270522. [PMID: 37954015 PMCID: PMC10639121 DOI: 10.3389/fbioe.2023.1270522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/19/2023] [Indexed: 11/14/2023] Open
Abstract
Background: Spinal fusion is the most common surgical treatment for the management of degenerative spinal disease. However, complications such as screw loosening lead to painful pseudoarthrosis, and are a common reason for revision. Optimization of screw trajectories to increase implant resistance to mechanical loading is essential. A recent optimization method has shown potential for determining optimal screw position and size based on areas of high bone elastic modulus (E-modulus). Aim: The aim of this biomechanical study was to verify the optimization algorithm for pedicle screw placement in a cadaveric study and to quantify the effect of optimization. The pull-out strength of pedicle screws with an optimized trajectory was compared to that of a traditional trajectory. Methods: Twenty-five lumbar vertebrae were instrumented with pedicle screws (on one side, the pedicle screws were inserted in the traditional way, on the other side, the screws were inserted using an optimized trajectory). Results: An improvement in pull-out strength and pull-out strain energy of the optimized screw trajectory compared to the traditional screw trajectory was only observed for E-modulus values greater than 3500 MPa cm3. For values of 3500 MPa cm3 or less, optimization showed no clear benefit. The median screw length of the optimized pedicle screws was significantly smaller than the median screw length of the traditionally inserted pedicle screws, p < 0.001. Discussion: Optimization of the pedicle screw trajectory is feasible, but seems to apply only to vertebrae with very high E-modulus values. This is likely because screw trajectory optimization resulted in a reduction in screw length and therefore a reduction in the implant-bone interface. Future efforts to predict the optimal pedicle screw trajectory should include screw length as a critical component of potential stability.
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Affiliation(s)
- Christos Tsagkaris
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Anna-Katharina Calek
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Marie-Rosa Fasser
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - José Miguel Spirig
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Sebastiano Caprara
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jonas Widmer
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
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Antes S, Moringlane R, von Eckardstein KL. Augmented Reality-Supported Rod Bending in Multilevel Spinal Fusion Using the ADVISE Software. World Neurosurg 2023; 178:96-100. [PMID: 37454904 DOI: 10.1016/j.wneu.2023.07.029] [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: 05/01/2023] [Revised: 07/05/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
BACKGROUND One of the most common reasons for poor patient outcomes and revision surgery in spinal fusion is hardware failure. Screw loosening or pullout occurs in up to one-quarter of all cases. It is known that even small screw-rod misalignments can cause significant mechanical overloads during rod fixation, which can result in hardware failure. To address this crucial surgical step, a novel augmented reality-assisted software was developed to generate custom rod templates that are precisely adapted to the individual patient. METHODS The novel software, which runs on a tablet, is used in spinal fusion surgery and is based on the use of a specific pedicle screw system, in which the polyaxial screw heads are connected to detachable guides. These guides can be recognized by the tablet camera and a light detection and ranging scanner. This image information is processed to determine the spatial positions of the screw heads and to calculate an ideally fitting rod template. RESULTS The calculated rod template is displayed in a 1-to-1 scale on the tablet screen. This template is used to cut and bend the rods of the pedicle screw system. Finally, the custom bent rod can be inserted into the screw heads without tension. CONCLUSIONS The augmented reality-assisted software is intended to give surgeons access to patient-specific intraoperative real-time data, helping them in bending rods that are more precisely adapted to the individual patient compared with the freehand technique.
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Affiliation(s)
- Sebastian Antes
- Department of Neurosurgery, Westpfalz-Klinikum GmbH, Kaiserslautern, Germany.
| | - Rene Moringlane
- Department of Neurosurgery, Westpfalz-Klinikum GmbH, Kaiserslautern, Germany
| | - Kajetan L von Eckardstein
- Department of Neurosurgery, Westpfalz-Klinikum GmbH, Kaiserslautern, Germany; Department of Neurosurgery, Universitätsmedizin Mannheim, Mannheim, Germany
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Wu LC, Hsieh YY, Tsuang FY, Kuo YJ, Chen CH, Chiang CJ. Pullout Strength of Pedicle Screws Inserted Using Three Different Techniques: A Biomechanical Study on Polyurethane Foam Block. Bioengineering (Basel) 2023; 10:660. [PMID: 37370591 DOI: 10.3390/bioengineering10060660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 05/08/2023] [Accepted: 05/25/2023] [Indexed: 06/29/2023] Open
Abstract
Pullout strength is an important indicator of the performance and longevity of pedicle screws and can be heavily influenced by the screw design, the insertion technique and the quality of surrounding bone. The purpose of this study was to investigate the pullout strength of three different pedicle screws inserted using three different strategies and with two different loading conditions. Three pedicle screws with different thread designs (single-lead-thread (SLT) screw, dual-lead-thread (DLT) screw and mixed-single-lead-thread (MSLT) screw) were inserted into a pre-drilled rigid polyurethane foam block using three strategies: (A) screw inserted to a depth of 33.5 mm; (B) screw inserted to a depth of 33.5 mm and then reversed by 3.5 mm to simulate an adjustment of the tulip height of the pedicle screw and (C) screw inserted to a depth of 30 mm. After insertion, each screw type was set up with and without a cyclic load being applied to the screw head prior to the pullout test. To ensure that the normality assumption is met, we applied the Shapiro-Wilk test to all datasets before conducting the non-parametric statistical test (Kruskal-Wallis test combined with pairwise Mann-Whitney-U tests). All screw types inserted using strategy A had a significantly greater pullout strength than those inserted using strategies B and C, regardless of if the screw was pre-loaded with a cyclic load prior to testing. Without the use of the cyclic pre-load, the MSLT screw had a greater pullout strength than the SLT and DLT screws for all three insertion strategies. However, the fixation strength of all screws was reduced when pre-loaded before testing, with the MSLT screw inserted using strategy B producing a significantly lower pullout strength than all other groups (p < 0.05). In contrast, the MSLT screw using insertion strategies A and C had a greater pullout strength than the SLT and DLT screws both with and without pre-loading. In conclusion, the MSLT pedicle screw exhibited the greatest pullout strength of the screws tested under all insertion strategies and loading conditions, except for insertion strategy B with a cyclic pre-load. While all screw types showed a reduced pullout strength when using insertion strategy B (screw-out depth adjustment), the MSLT screw had the largest reduction in pullout strength when using a pre-load before testing. Based on these findings, during the initial screw insertion, it is recommended to not fully insert the screw thread into the bone and to leave a retention length for depth adjustment to avoid the need for screw-out adjustment, as with insertion strategy B.
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Affiliation(s)
- Lien-Chen Wu
- Department of Orthopaedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
- Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei City 11031, Taiwan
- Graduate Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei City 11031, Taiwan
| | - Yueh-Ying Hsieh
- Department of Orthopaedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
- Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei City 11031, Taiwan
| | - Fon-Yih Tsuang
- Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, Taipei City 100225, Taiwan
- Spine Tumor Center, National Taiwan University Hospital, Taipei City 100225, Taiwan
| | - Yi-Jie Kuo
- Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei City 11031, Taiwan
- Department of Orthopedic Surgery, Wan Fang Hospital, Taipei Medical University, Taipei City 11696, Taiwan
| | - Chia-Hsien Chen
- Department of Orthopaedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
- Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei City 11031, Taiwan
- School of Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei City 11031, Taiwan
| | - Chang-Jung Chiang
- Department of Orthopaedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
- Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei City 11031, Taiwan
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Nagashima K, Hara Y, Mutsuzaki H, Totoki Y, Okano E, Mataki K, Matsumoto Y, Yanagisawa Y, Noguchi H, Sogo Y, Ito A, Koda M, Yamazaki M. Clinical Trial for the Safety and Feasibility of Pedicle Screws Coated with a Fibroblast Growth Factor-2-Apatite Composite Layer for Posterior Cervical Fusion Surgery. J Clin Med 2023; 12:jcm12030947. [PMID: 36769595 PMCID: PMC9917677 DOI: 10.3390/jcm12030947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/13/2023] [Accepted: 01/19/2023] [Indexed: 01/28/2023] Open
Abstract
To solve the instrument loosening problem, we developed a fibroblast growth factor-2-calcium phosphate composite layer as a novel coating material to improve screw fixation strength. The primary aim of the present study was to demonstrate the safety and feasibility of screws coated with the FGF-2-calcium phosphate composite layer for posterior instrumented surgery of the cervical spine. The trial design was a single-arm, open-label, safety and feasibility study. Patients receiving fusion of the cervical spine from C2 (or C3) to C7 (or T1) were recruited. The primary endpoint to confirm safety was any screw-related adverse events. Seven patients who underwent posterior fusion surgery of the cervical spine were enrolled in the present study. The coated pedicle screws were inserted bilaterally into the lowest instrumented vertebrae. There was only one severe adverse event unrelated with the coated screw. Three out of the fourteen coated screws showed loosening. The present results prove the safety and feasibility of pedicle screws coated with the FGF-2-calcium phosphate composite layer for fusion surgery in the cervical spine. This is the first step to apply this novel surface coating in the field of spine surgery.
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Affiliation(s)
- Katsuya Nagashima
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Yuki Hara
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Hirotaka Mutsuzaki
- Department of Orthopedic Surgery, Ibaraki Prefectural University of Health Sciences, Ami 300-0394, Japan
| | - Yasukazu Totoki
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Eriko Okano
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Kentaro Mataki
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Yukei Matsumoto
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Yohei Yanagisawa
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Hiroshi Noguchi
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Yu Sogo
- Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8560, Japan
| | - Atsuo Ito
- Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8560, Japan
| | - Masao Koda
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
- Correspondence:
| | - Masashi Yamazaki
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
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Predicting pullout strength of pedicle screws in broken bones from X-ray images. J Mech Behav Biomed Mater 2022; 134:105366. [PMID: 35870229 DOI: 10.1016/j.jmbbm.2022.105366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/23/2022] [Accepted: 07/09/2022] [Indexed: 12/19/2022]
Abstract
Pedicle screw fixation is one of the most common procedures used in spinal fusion surgery. The screw loosening is a major concern, which may be caused by broken pedicles. In vitro pullout tests or insertion torque are the main approaches for assessing the stability of the screw; however, direct evidence was lacking for clinical human spines. Here, we aim to provide a model that can predict the pullout strengths of pedicle screws in various pedicle conditions from X-ray images. A weighted embedded bone volume (EBV) model is proposed for pullout strengths prediction by considering the bone heterogeneity and confinement of the screw. We showed that the pullout strength is proportional to the EBV for homogeneous bone and the weighted EBV for layered composite bone. The proposed weighted EBV model is validated with in vitro Sawbones® pullout experiments. The results show that the model has better accuracy than the simple EBV model, with a coefficient of determination of 0.94. The proposed weighted EBV model can help assess the stability of a pedicle screw in a broken pedicle by simply examining 2D X-ray images.
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