PMID- 32103040
OWN - NLM
STAT- MEDLINE
DCOM- 20201124
LR  - 20210225
IS  - 2045-2322 (Electronic)
IS  - 2045-2322 (Linking)
VI  - 10
IP  - 1
DP  - 2020 Feb 26
TI  - The effect of posterior tethers on the biomechanics of proximal junctional 
      kyphosis: The whole human finite element model analysis.
PG  - 3433
LID - 10.1038/s41598-020-59179-w [doi]
LID - 3433
AB  - Little is known about the effects of posterior tethers on the development of 
      proximal junctional kyphosis (PJK). We evaluated the ability of posterior tethers 
      to the proximal motion segment stiffness in long instrumented spinal 
      instrumentation and fusion using a whole body human FE model. A series of finite 
      element (FE) analysis of long segmental spinal fusion (SF) from the upper 
      thoracic vertebra (T1) or lower thoracic vertebra (T9) to the sacrum with pedicle 
      screws and rods were performed using an entire human body FE model (includes 
      234,910 elements), and compressive stresses (CS) on the anterior column, and 
      tensile stresses (TS) on the posterior ligamentous complex (PLC) in the 
      upper-instrumented vertebra (UIV) and the vertebra adjacent to the UIV (UIV + 1) 
      were evaluated with posterior tethers or without posterior tethers. The models 
      were tested at three T1 tilts (0, 20, 40 deg.), with 20% muscle contraction. 
      Deformable material models were assigned to all body parts. Muscle-tendon 
      complexes were modeled by truss elements with a Hill-type muscle material model. 
      The CS of anterior column decreased with increasing T1 slope with tethers in both 
      models, while the CS remained relatively large in T9 model compared with T1 model 
      (T1 UIV; 0.96 to 1.56 MPa, T9 UIV; 4.79 to 5.61 MPa). The TS of the supraspinous 
      ligament was markedly reduced in both T1 and T9 models with posterior tethers 
      (11-35%). High vertebral CS on UIV and UIV + 1 were seen in the T9 UIV model, and 
      the TS on the PLC were increased in both UIV models. Posterior tethers may 
      decrease PJK development after SF with a proximal thoracic UIV, while both 
      posterior tethers and vertebral augmentation may be necessary to reduce PJK 
      development with a lower thoracic UIV.
FAU - Yagi, Mitsuru
AU  - Yagi M
AD  - Department of Orthopedic Surgery, Keio University School of Medicine, 
      Shinjuku-ku, Tokyo, Japan. yagiman@keio.jp.
AD  - Department of Orthopedic Surgery, National Hospital Organization Murayama Medical 
      Center, Musashimurayama city, Tokyo, Japan. yagiman@keio.jp.
FAU - Nakahira, Yuko
AU  - Nakahira Y
AD  - Toyota Central R&D Labs Inc., Nagakute city, Aichi, Japan.
FAU - Watanabe, Kota
AU  - Watanabe K
AD  - Department of Orthopedic Surgery, Keio University School of Medicine, 
      Shinjuku-ku, Tokyo, Japan.
FAU - Nakamura, Masaya
AU  - Nakamura M
AD  - Department of Orthopedic Surgery, Keio University School of Medicine, 
      Shinjuku-ku, Tokyo, Japan.
FAU - Matsumoto, Morio
AU  - Matsumoto M
AD  - Department of Orthopedic Surgery, Keio University School of Medicine, 
      Shinjuku-ku, Tokyo, Japan.
FAU - Iwamoto, Masami
AU  - Iwamoto M
AD  - Toyota Central R&D Labs Inc., Tokyo, Japan. iwamoto@mosk.tytlabs.co.jp.
LA  - eng
PT  - Journal Article
DEP - 20200226
PL  - England
TA  - Sci Rep
JT  - Scientific reports
JID - 101563288
SB  - IM
MH  - Biomechanical Phenomena
MH  - Compressive Strength
MH  - *Finite Element Analysis
MH  - Humans
MH  - Kyphosis/*physiopathology
MH  - Ligaments, Articular/physiology
MH  - Muscle Contraction
MH  - Pedicle Screws
MH  - Spinal Fusion/methods
MH  - Tensile Strength
MH  - Thoracic Vertebrae/surgery
PMC - PMC7044281
COIS- The authors declare no competing interests.
EDAT- 2020/02/28 06:00
MHDA- 2020/11/25 06:00
PMCR- 2020/02/26
CRDT- 2020/02/28 06:00
PHST- 2019/10/07 00:00 [received]
PHST- 2020/01/27 00:00 [accepted]
PHST- 2020/02/28 06:00 [entrez]
PHST- 2020/02/28 06:00 [pubmed]
PHST- 2020/11/25 06:00 [medline]
PHST- 2020/02/26 00:00 [pmc-release]
AID - 10.1038/s41598-020-59179-w [pii]
AID - 59179 [pii]
AID - 10.1038/s41598-020-59179-w [doi]
PST - epublish
SO  - Sci Rep. 2020 Feb 26;10(1):3433. doi: 10.1038/s41598-020-59179-w.