Comparative biomechanical analysis of an improved novel pedicle screw with sheath and bone cement

Tomoyuki Takigawa, Masato Tanaka, Hitoshi Konishi, Hisanori Ikuma, Haruo Misawa, Yoshihisa Sugimoto, Kazuo Nakanishi, Koichi Kuramoto, Keiichiro Nishida, Toshihumi Ozaki

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

STUDY DESIGN: A human cadaveric biomechanical study of fixation strength of an improved novel pedicle screw (NPS) with cement and a conventional screw. OBJECTIVE: To clarify whether the NPS has adequate fixation strength without leakage in vertebrae with low bone quality. SUMMARY OF BACKGROUND DATA: The fixation strength of pedicle screws decreases in frail spines of elderly osteoporotic patients. Augmentation of screw fixation with bone cement must be balanced against increased difficulty of screw removal and risk of cement leakage. We developed the NPS consisting of an internal screw and an outer sheath to mitigate the disadvantages of cement augmentation. METHODS: The T12 and L1 vertebrae obtained from 18 formalin preserved cadavers (11 males and 7 females; mean age, 82.7 y) were used. The mean bone mineral density was 0.39±0.14 g/cm. The NPS was inserted into one pedicle of each vertebra and the control screw, a Compact CD2 screw, was inserted into the contralateral pedicle. Both screws were 6 mm in diameter and 40 mm in length. Pull-out tests were performed at a crosshead speed of 10 mm/min. Cyclic loading tests were performed with a maximum 250 N load at 2 Hz until 30,000 cycles. RESULTS: Cement leakage did not occur in any of the specimens tested. The mean maximum force at pull-out was 760±344 N for the NPS and 346±172 N for the control screw (P

Original languageEnglish
Pages (from-to)462-467
Number of pages6
JournalJournal of Spinal Disorders and Techniques
Volume20
Issue number6
DOIs
Publication statusPublished - Aug 2007

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Bone Cements
Spine
Frail Elderly
Cadaver
Bone Density
Formaldehyde
Pedicle Screws
Bone and Bones

Keywords

  • Biomechanics
  • Osteoporosis
  • Pedicle screw
  • Polymethylmethacrylate augmentation

ASJC Scopus subject areas

  • Clinical Neurology
  • Surgery
  • Orthopedics and Sports Medicine

Cite this

Comparative biomechanical analysis of an improved novel pedicle screw with sheath and bone cement. / Takigawa, Tomoyuki; Tanaka, Masato; Konishi, Hitoshi; Ikuma, Hisanori; Misawa, Haruo; Sugimoto, Yoshihisa; Nakanishi, Kazuo; Kuramoto, Koichi; Nishida, Keiichiro; Ozaki, Toshihumi.

In: Journal of Spinal Disorders and Techniques, Vol. 20, No. 6, 08.2007, p. 462-467.

Research output: Contribution to journalArticle

Takigawa, Tomoyuki ; Tanaka, Masato ; Konishi, Hitoshi ; Ikuma, Hisanori ; Misawa, Haruo ; Sugimoto, Yoshihisa ; Nakanishi, Kazuo ; Kuramoto, Koichi ; Nishida, Keiichiro ; Ozaki, Toshihumi. / Comparative biomechanical analysis of an improved novel pedicle screw with sheath and bone cement. In: Journal of Spinal Disorders and Techniques. 2007 ; Vol. 20, No. 6. pp. 462-467.
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