Advantages of Combined Use of Claw Hooks and Sublaminar Wires as the Upper Foundation of Long Fixation from the Thoracic Spine to the Pelvis in Osteoporotic Cases: A Finite Element Analysis of Proximal Junction Stress

Introduction: This study aimed to compare the biomechanical stress at the proximal junctional aspect between the conventional pedicle screw (PS) fixation (PSF) and the low PS density fixation (LPF) method. Methods: This study involved 10 patients, half of whom have non-osteoporosis and the other hal...

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Main Authors: Takuhei Kozaki, Takachika Shimizu, Akimasa Murata, Ryuichiro Nakanishi, Takahiro Kozaki, Ei Yamamoto, Shunji Tsutsui, Mamoru Kawakami, Hiroshi Yamada
Format: Article
Language:English
Published: The Japanese Society for Spine Surgery and Related Research 2025-03-01
Series:Spine Surgery and Related Research
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Online Access:https://www.jstage.jst.go.jp/article/ssrr/9/2/9_2024-0169/_pdf/-char/en
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_version_ 1849731227095924736
author Takuhei Kozaki
Takachika Shimizu
Akimasa Murata
Ryuichiro Nakanishi
Takahiro Kozaki
Ei Yamamoto
Shunji Tsutsui
Mamoru Kawakami
Hiroshi Yamada
author_facet Takuhei Kozaki
Takachika Shimizu
Akimasa Murata
Ryuichiro Nakanishi
Takahiro Kozaki
Ei Yamamoto
Shunji Tsutsui
Mamoru Kawakami
Hiroshi Yamada
author_sort Takuhei Kozaki
collection DOAJ
description Introduction: This study aimed to compare the biomechanical stress at the proximal junctional aspect between the conventional pedicle screw (PS) fixation (PSF) and the low PS density fixation (LPF) method. Methods: This study involved 10 patients, half of whom have non-osteoporosis and the other half have osteoporosis. We made two types of intact models (one is from the upper thoracic-to-pelvis model, and the other is from the lower thoracic-to-pelvis model). From the intact models, we constructed two kinds of fusion models: (1) PSF and (2) LPF. The LPF method was as follows: The claw hooks (the combination of the down-going transverse process hooks and facet hooks) were set at the upper instrumented vertebra (UIV) and sublaminar wires at the thoracic spine and PSs at the lumbo-pelvis. Results: Upper thoracic to pelvis fixation model In non-osteoporosis, no significant difference between the PSF and LPF is found. In osteoporosis, the von Mises stresses of the vertebra body at UIV, UIV+1, and disc were significantly lower in LPF than in PSF. Lower thoracic-to-pelvis fixation model In non-osteoporosis, the average von Mises stress of the vertebral body at UIV+1 and the maximum stress at UIV were lower in LPF than in PSF; however, no significant difference was found in the others. In osteoporosis, the von Mises stress was significantly lower in LPF than in PSF. Conclusions: The claw hooks stabilized the vertebra body at UIV firmly, and sublaminar wires reduced load translation from the fixed spine.
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publisher The Japanese Society for Spine Surgery and Related Research
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spelling doaj-art-3efa11a494e449ea890a5a5d163a4a7a2025-08-20T03:08:37ZengThe Japanese Society for Spine Surgery and Related ResearchSpine Surgery and Related Research2432-261X2025-03-019220221010.22603/ssrr.2024-01692024-0169Advantages of Combined Use of Claw Hooks and Sublaminar Wires as the Upper Foundation of Long Fixation from the Thoracic Spine to the Pelvis in Osteoporotic Cases: A Finite Element Analysis of Proximal Junction StressTakuhei Kozaki0Takachika Shimizu1Akimasa Murata2Ryuichiro Nakanishi3Takahiro Kozaki4Ei Yamamoto5Shunji Tsutsui6Mamoru Kawakami7Hiroshi Yamada8Department of Orthopaedic Surgery, Wakayama Medical UniversityDepartment of Orthopaedic Surgery, Gunma Spine Center (Harunaso Hospital)Department of Orthopaedic Surgery, Wakayama Medical UniversityDepartment of Orthopaedic Surgery, Wakayama Medical UniversityDepartment of Orthopaedic Surgery, Wakayama Medical UniversityDepartment of Biomedical Engineering, Faculty of Biology-Oriented Science and Technology, Kindai UniversityDepartment of Orthopaedic Surgery, Wakayama Medical UniversityDepartment of Orthopaedic Surgery, Saiseikai Wakayama HospitalDepartment of Orthopaedic Surgery, Wakayama Medical UniversityIntroduction: This study aimed to compare the biomechanical stress at the proximal junctional aspect between the conventional pedicle screw (PS) fixation (PSF) and the low PS density fixation (LPF) method. Methods: This study involved 10 patients, half of whom have non-osteoporosis and the other half have osteoporosis. We made two types of intact models (one is from the upper thoracic-to-pelvis model, and the other is from the lower thoracic-to-pelvis model). From the intact models, we constructed two kinds of fusion models: (1) PSF and (2) LPF. The LPF method was as follows: The claw hooks (the combination of the down-going transverse process hooks and facet hooks) were set at the upper instrumented vertebra (UIV) and sublaminar wires at the thoracic spine and PSs at the lumbo-pelvis. Results: Upper thoracic to pelvis fixation model In non-osteoporosis, no significant difference between the PSF and LPF is found. In osteoporosis, the von Mises stresses of the vertebra body at UIV, UIV+1, and disc were significantly lower in LPF than in PSF. Lower thoracic-to-pelvis fixation model In non-osteoporosis, the average von Mises stress of the vertebral body at UIV+1 and the maximum stress at UIV were lower in LPF than in PSF; however, no significant difference was found in the others. In osteoporosis, the von Mises stress was significantly lower in LPF than in PSF. Conclusions: The claw hooks stabilized the vertebra body at UIV firmly, and sublaminar wires reduced load translation from the fixed spine.https://www.jstage.jst.go.jp/article/ssrr/9/2/9_2024-0169/_pdf/-char/enlow pedicle screw density fixationthoracic claw hookssublaminar wiresosteoporosisproximal junctional kyphosisfinite element analysis
spellingShingle Takuhei Kozaki
Takachika Shimizu
Akimasa Murata
Ryuichiro Nakanishi
Takahiro Kozaki
Ei Yamamoto
Shunji Tsutsui
Mamoru Kawakami
Hiroshi Yamada
Advantages of Combined Use of Claw Hooks and Sublaminar Wires as the Upper Foundation of Long Fixation from the Thoracic Spine to the Pelvis in Osteoporotic Cases: A Finite Element Analysis of Proximal Junction Stress
Spine Surgery and Related Research
low pedicle screw density fixation
thoracic claw hooks
sublaminar wires
osteoporosis
proximal junctional kyphosis
finite element analysis
title Advantages of Combined Use of Claw Hooks and Sublaminar Wires as the Upper Foundation of Long Fixation from the Thoracic Spine to the Pelvis in Osteoporotic Cases: A Finite Element Analysis of Proximal Junction Stress
title_full Advantages of Combined Use of Claw Hooks and Sublaminar Wires as the Upper Foundation of Long Fixation from the Thoracic Spine to the Pelvis in Osteoporotic Cases: A Finite Element Analysis of Proximal Junction Stress
title_fullStr Advantages of Combined Use of Claw Hooks and Sublaminar Wires as the Upper Foundation of Long Fixation from the Thoracic Spine to the Pelvis in Osteoporotic Cases: A Finite Element Analysis of Proximal Junction Stress
title_full_unstemmed Advantages of Combined Use of Claw Hooks and Sublaminar Wires as the Upper Foundation of Long Fixation from the Thoracic Spine to the Pelvis in Osteoporotic Cases: A Finite Element Analysis of Proximal Junction Stress
title_short Advantages of Combined Use of Claw Hooks and Sublaminar Wires as the Upper Foundation of Long Fixation from the Thoracic Spine to the Pelvis in Osteoporotic Cases: A Finite Element Analysis of Proximal Junction Stress
title_sort advantages of combined use of claw hooks and sublaminar wires as the upper foundation of long fixation from the thoracic spine to the pelvis in osteoporotic cases a finite element analysis of proximal junction stress
topic low pedicle screw density fixation
thoracic claw hooks
sublaminar wires
osteoporosis
proximal junctional kyphosis
finite element analysis
url https://www.jstage.jst.go.jp/article/ssrr/9/2/9_2024-0169/_pdf/-char/en
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