IJAT Vol.11 No.6 pp. 895-901
doi: 10.20965/ijat.2017.p0895


Examination of a Low-Profile Spinal Implant

Takuto Iwade*,†, Noriyuki Hisamori**, Junichi Fujita***, and Kenji Yamaya***

*Graduate School of Science and Technology, Sophia University
7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan

Corresponding author

**Department of Engineering and Applied Science, Sophia University, Tokyo, Japan

***MIZUHO Corporation, Niigata, Japan

April 28, 2017
August 17, 2017
Online released:
October 31, 2017
November 5, 2017
low profile, removal torque value, Ti-6Al-4V alloys, spine implant, screw thread

Most spine implant devices are fabricated outside Japan, and therefore do not always fit the bodies of Japanese people. This causes a quality-of-life (QOL) problem in which patients feel the embedded implant devices on their back. The aim of this study was to develop more compact and lower-profile spine implant devices. Three types of devices with different heights and different screw threads were created, and the removal torque (fitting force) of the devices was measured after a static load test and cyclic load test. In addition, the screw thread surface was observed in detail after the tests. The results indicated that the mechanism of the reduction in the fitting force was related to partial contact due to abrasion or plastic deformation of the screw thread surface and decrease in the contact area between the screw threads caused by the increased diameter of the upper opening of the implant device after tightening. Therefore, we concluded that lowering the height of the implant device, securing the number of the screw threads, and securing the contact area of the threads are important in developing a low-profile spine implant.

Cite this article as:
T. Iwade, N. Hisamori, J. Fujita, and K. Yamaya, “Examination of a Low-Profile Spinal Implant,” Int. J. Automation Technol., Vol.11 No.6, pp. 895-901, 2017.
Data files:
  1. [1] K. Oribe, K. Hasegawa, K. Kitahara, T. Tamura, K. Narita, S. Yamanaka, M. Nakai, K. Takakuda, and M. Niinomi, “Current Situation and Challenges and Prospects of the Design and Manufacturing Process of the Spinal Implants,” Materia Japan, Vol.55, No.4, pp. 142-146, 2016.
  2. [2] [accessed August 31, 2016]
  3. [3] D. K. Palmer et al., “Stem fracture after total facet replacement in the lumbar spine: a report of two cases and review of the literature,” The Spine J., Vol.11, pp. e15-e19, 2011.
  4. [4] K. Hasegawa, “Present and Future Requirments for Materials in Spine Surgery,” Materia Japan, Vol.53, No.4, pp. 134-138, 2013.
  5. [5] Y. Kiriyama and N. Yamazaki, “Biomechanical Analysis of Spinal Instruments Applying Rigid Body and Spring Model,” Biomechanisms, Vol.17, pp. 185-194, 2004.
  6. [6] S. A. Gehrke and G. W. Marin, “Biomechanical evaluation of dental implants with three different designs: Removal torque and resonance frequency analysis in rabbits,” Annals of Anatomy, Vol.199, pp. 30-35, 2015.
  7. [7] T. Jun, K. Yoo, J. Choi, J. Ha, T. Yoon, S. Ahn, D. Lim, and C. Ko, “A Study on Biomechanical Stability Analysis of Locking System in Poly-axial Pedicle Screws,” Proc. of the 20th Bioengineering Conf., 2007 Annual Meeting of BED/JSME, pp. 185-186, 2008.

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Last updated on Jun. 19, 2024