Implant Analysis on the Lumbar-Sacrum Vertebrae Using Finite Element Method

  • A. KavithaEmail author
  • G. Sudhir
  • T. S. Ranjani.
  • V. Sarah Rajitha Thilagam
  • S. Vinutha


Disc degeneration is a common phenomena occurring due to ageing and is observed as changes occurring in the anatomical and physiological functioning of the disc. Degenerative Disc Disease (DDD) occurs when the inner core leaks out through the outer portion of the disc which places pressure on nearby nerves or the spinal cord. Intervertebral discs deteriorate and grow thinner as age progresses, which cause lower back pain. In many cases this is treated with medication and in severe cases surgery is preferred. In surgical procedures, for the fusion of bone in degenerated regions, pedicle screw implant has gained more importance. But in post-operative condition, loosening of screw occurs in the lower lumbar spine L5-S1 region. This is due to the high stress developing on the screws post surgery. The objective of this work is to compare the stress developed in the normal and abnormal subjects for various loads using finite element analysis. The data was acquired from two subjects (Normal −1, aged 43 and the other abnormal −1 diagnosed with DDD aged 61). A 3D model was generated from CT images by identifying the regions of interest. In addition to it volume and surface rendering techniques were employed in obtaining a 3D model. Intervertebral disc for L5-S1region was generated and pedicle screw implant was designed. The screw along with the vertebrae was subjected to stress analysis using Finite element method . Analysis was carried out for various loads applied on the L5-S1 region. It was observed that the stress values varied from 1.979e+02 to 1.371e+04 without screws and from 5.831e+04 to 6.936e+05 with the screws for normal subject. For the abnormal subject, it has been observed that the stress values varied from 1.337e+02 to 6.269e+03 for mild degeneration and from 1.029e+02 to 5.051e+03 for severe degeneration without the screws. Further, it has been noted that the stress values varied from 1.792e+04 to 2.130e+05 for mild degeneration and from 5.831e+04 to 6.936e+05 for severe degeneration with the implant placed. This study proves to be clinically highly relevant in addressing post-surgery issues due to placement of implants and in analysing the subjective appropriateness of the implant being used.


Degenerative disc disease Implant design Finite element analysis Lumbar-sacrum vertebrae 


  1. 1.
    Jean-Marc Mac-Thiong P (2011) Age- and sex-related variations in sagittal sacropelvic morphology and balance in asymptomatic adults. Eur Spine JGoogle Scholar
  2. 2.
    Guan Y (2008) Internal and external responses of anterior lumbar/lumbosacral fusion: nonlinear finite element analysis. J Spinal Disord TechGoogle Scholar
  3. 3.
    Znne P (2003) Factors influencing stresses in the lumbar spine after the insertion of intervertebral cages: finite element analysis. Eur Spine JGoogle Scholar
  4. 4.
    Sharma, Pure flexion extension moments using a pair of concentrated axial loads on top of the upper vertebra. In: Spine surgery, 3rd ed., Chap 22Google Scholar
  5. 5.
    Kumaresan S, Wheeldon JA Pure moments by using a force couple acting on the rigid plate attached to the superior vertebra. In: Spine surgery, 3rd ed., Chap. 22Google Scholar
  6. 6.
    Park (2012) biomechanical effects of the number of ventral fixation rods, with or without dorsal fixation, on the spinal stability of thoracolumbar burst fracture constructs. Spinal surgery 2Google Scholar
  7. 7.
    Jovanovic JD, Jovanović M Lj (2010) Finite element modeling of the vertebra with geometry and material properties retrieved from CT-Scan DataGoogle Scholar
  8. 8.
    Kang S-H, Kim K-T, Won Park S, Kim Y-B (2011) A case of pedicle screw loosening treated by modified transpedicular screw augmentation with polymethylmethacrylate. J Korean Neurosurg SocGoogle Scholar
  9. 9.
    Cho W, Cho SK, Wu C (2011) The biomechanics of pedicle screw-based Instrumentation. Korean Neurosurg SocGoogle Scholar
  10. 10.
    Li H (2011) An approach to lumbar vertebra biomechanical analysis using the finite element modeling based on CT Images. In: Theory and applications of CT imaging and analysis, Chap 10, pp 165–180Google Scholar
  11. 11.
    Lehman RA, Kuklo TR, O’Brien MF (2002) Biomechanics of thoracic pedicle screw. Sem Spine Surgery 14(1):8–15Google Scholar
  12. 12.
    Singh Roop, Sharma Sansar Chand, Mittal Rajeev, Sharma Ashwini (2003) Traumatic spinal cord injuries in haryana: an epidemiological study. Indian J Commun Med 28:184–186Google Scholar
  13. 13.
    Prescher A (1998) Anatomy and pathology of aging Spine. Eur J Radiol 181–195Google Scholar
  14. 14.
    Zhang QH, Teo EC (2008) Finite element application in implant research for treatment of lumbar degenerative disc disease. Med Eng Phys 30:1246–1256Google Scholar
  15. 15.
    Adams M, Freeman BJC, Morrison HP, Nelson LW Spine 25:1625–1636Google Scholar
  16. 16.
    Agarwal P, Upadhyay P, Raja K (2007) A demographic profile of traumatic and non-traumatic spinal injury cases: a hospital-based study from India. J Int Spinal Cord Soc 597–602Google Scholar

Copyright information

© Springer Science+Business Media Singapore 2017

Authors and Affiliations

  • A. Kavitha
    • 1
    Email author
  • G. Sudhir
    • 2
  • T. S. Ranjani.
    • 1
  • V. Sarah Rajitha Thilagam
    • 1
  • S. Vinutha
    • 1
  1. 1.Centre for Healthcare Technologies, Department of Biomedical EngineeringSSN College of EngineeringChennaiIndia
  2. 2.Orthopedic SurgeonSri Ramachandra Medical College and Research InstituteChennaiIndia

Personalised recommendations