Adaptive remodeling at the pedicle due to pars fracture: a finite element analysis study

Laboratory investigation

View More View Less
  • 1 Orthopedic Biomechanics Laboratory, Loma Linda University, Loma Linda, California; and
  • | 2 Spine Research Laboratory and
  • | 3 Neurological Institute, Cleveland Clinic, Cleveland, Ohio
Restricted access

Purchase Now

USD  $45.00

Spine - 1 year subscription bundle (Individuals Only)

USD  $376.00

JNS + Pediatrics + Spine - 1 year subscription bundle (Individuals Only)

USD  $612.00
Print or Print + Online

Object

Spondylolysis is a common condition among the general population and a major cause of back pain in young athletes. This condition can be difficult to detect with plain radiography and has been reported to lead to contralateral pars fracture or pedicle fracture in the terminal stages. Interestingly, some patients with late-stage spondylolysis are observed to have radiographic or CT evidence of a sclerotic pedicle on the side contralateral to the spondylolysis. Although computational studies have shown stress elevation in the contralateral pedicle after a pars fracture, it is not known if these changes would cause sclerotic changes in the contralateral pedicle. The objective of this study was to investigate the adaptive remodeling process at the pedicle due to a contralateral spondylolysis using finite element analysis.

Methods

A multiscale finite element model of a vertebra was obtained by combining a continuum model of the posterior elements with a voxel-based pedicle section. Extension loading conditions were applied with or without a fracture at the contralateral pars to analyze the stresses in the contralateral pedicle. A remodeling algorithm was used to simulate and assess density changes in the contralateral pedicle.

Results

The remodeling algorithm demonstrated an increase in bone formation around the perimeter of the contralateral pedicle with some localized loss of mass in the region of cancellous bone.

Conclusions

The authors' results indicated that a pars fracture results in sclerotic changes in the contralateral pedicle. Such a remodeling process could increase overall bone mass. However, focal bone loss in the region of the cancellous bone of the pedicle might predispose the pedicle to microfractures. This phenomenon explains, at least in part, the origin of pedicle stress fractures in the sclerotic contralateral pedicles of patients with unilateral spondylolysis.

Abbreviations used in this paper:

FE = finite element; SED = strain energy density.

Spine - 1 year subscription bundle (Individuals Only)

USD  $376.00

JNS + Pediatrics + Spine - 1 year subscription bundle (Individuals Only)

USD  $612.00
  • 1

    Amato M, , Totty WG, & Gilula LA: Spondylolysis of the lumbar spine: demonstration of defects and laminal fragmentation. Radiology 153:627629, 1984

    • Search Google Scholar
    • Export Citation
  • 2

    Campbell RS, , Grainger AJ, , Hide IG, , Papastefanou S, & Greenough CG: Juvenile spondylolysis: a comparative analysis of CT, SPECT and MRI. Skeletal Radiol 34:6373, 2005

    • Search Google Scholar
    • Export Citation
  • 3

    Cowin SC: Bone Mechanics Boca Raton, FL, CRC Press, 1989

  • 4

    Downey EF Jr, , Nason SS, , Majd M, & McSweeney WJ: Asymmetrical facet joints. Another cause for the sclerotic pedicle. Spine (Phila Pa 1976) 8:340342, 1983

    • Search Google Scholar
    • Export Citation
  • 5

    Goel VK, , Ramirez SA, , Kong W, & Gilbertson LG: Cancellous bone Young's modulus variation within the vertebral body of a ligamentous lumbar spine—application of bone adaptive remodeling concepts. J Biomech Eng 117:266271, 1995

    • Search Google Scholar
    • Export Citation
  • 6

    Gunzburg R, & Fraser RD: Stress fracture of the lumbar pedicle. Case reports of “pediculolysis” and review of the literature. Spine (Phila Pa 1976) 16:185189, 1991

    • Search Google Scholar
    • Export Citation
  • 7

    Inceoğlu S, & Mageswaran P: Multi-scale finite element modelling at the posterior lumbar vertebra: analysis of pedicle stresses due to pars fracture. Comput Methods Biomech Biomed Engin 17:787791, 2014

    • Search Google Scholar
    • Export Citation
  • 8

    Jackson DW, , Wiltse LL, & Cirincoine RJ: Spondylolysis in the female gymnast. Clin Orthop Relat Res 117 6873, 1976

  • 9

    Jacobs CR, , Levenston ME, , Beaupré GS, , Simo JC, & Carter DR: Numerical instabilities in bone remodeling simulations: the advantages of a node-based finite element approach. J Biomech 28:449459, 1995

    • Search Google Scholar
    • Export Citation
  • 10

    Lomasney L, , Schwartzers D, , Demos T, & Ghanayem A: Radiologic case study. Vertebral pedicle sclerosis. Orthopedics 21:215216, 219220, 224, 1998

    • Search Google Scholar
    • Export Citation
  • 11

    Micheli LJ, & Curtis C: Stress fractures in the spine and sacrum. Clin Sports Med 25:7588, ix, 2006

  • 12

    Modic MT: Editorial. Modic Type 1 and Type 2 changes. J Neurosurg Spine 6:150151, 2007

  • 13

    Modic MT, , Masaryk TJ, , Ross JS, & Carter JR: Imaging of degenerative disk disease. Radiology 168:177186, 1988

  • 14

    Roche MB, & Rowe GG: The incidence of separate neural arch and coincident bone variations; a summary. J Bone Joint Surg Am 34-A:491494, 1952

    • Search Google Scholar
    • Export Citation
  • 15

    Roche MB, & Rowe GG: The incidence of separate neural arch and coincident bone variations; a survey of 4,200 skeletons. Anat Rec 109:233252, 1951

    • Search Google Scholar
    • Export Citation
  • 16

    Rossi F: Spondylolysis, spondylolisthesis and sports. J Sports Med Phys Fitness 18:317340, 1978

  • 17

    Sairyo K, , Katoh S, , Sasa T, , Yasui N, , Goel VK, & Vadapalli S, et al.: Athletes with unilateral spondylolysis are at risk of stress fracture at the contralateral pedicle and pars interarticularis: a clinical and biomechanical study. Am J Sports Med 33:583590, 2005

    • Search Google Scholar
    • Export Citation
  • 18

    Sairyo K, , Katoh S, , Takata Y, , Terai T, , Yasui N, & Goel VK, et al.: MRI signal changes of the pedicle as an indicator for early diagnosis of spondylolysis in children and adolescents: a clinical and biomechanical study. Spine (Phila Pa 1976) 31:206211, 2006

    • Search Google Scholar
    • Export Citation
  • 19

    Sharma GB, , Debski RE, , McMahon PJ, & Robertson DD: Adaptive glenoid bone remodeling simulation. J Biomech 42:14601468, 2009

  • 20

    Sherman FC, , Wilkinson RH, & Hall JE: Reactive sclerosis of a pedicle and spondylolysis in the lumbar spine. J Bone Joint Surg Am 59:4954, 1977

    • Search Google Scholar
    • Export Citation
  • 21

    Sirvanci M, , Ulusoy L, & Duran C: Pedicular stress fracture in lumbar spine. Clin Imaging 26:187193, 2002

  • 22

    Sty JR, , Starshak RJ, & Babbitt DP: Bone scintigraphy: the sclerotic pedicle (Wilkinson syndrome). Clin Nucl Med 5:558, 1980

  • 23

    Ulmer JL, , Elster AD, , Mathews VP, & Allen AM: Lumbar spondylolysis: reactive marrow changes seen in adjacent pedicles on MR images. AJR Am J Roentgenol 164:429433, 1995

    • Search Google Scholar
    • Export Citation
  • 24

    Weinans H, , Huiskes R, , van Rietbergen B, , Sumner DR, , Turner TM, & Galante JO: Adaptive bone remodeling around bonded noncemented total hip arthroplasty: a comparison between animal experiments and computer simulation. J Orthop Res 11:500513, 1993

    • Search Google Scholar
    • Export Citation
  • 25

    Yochum TR, , Sellers LT, , Oppenheimer DA, , Peterson CK, , Kirton CW, & Dal Mas EC, et al.: The sclerotic pedicle—how many causes are there?. Skeletal Radiol 19:411417, 1990

    • Search Google Scholar
    • Export Citation

Metrics

All Time Past Year Past 30 Days
Abstract Views 233 115 9
Full Text Views 309 12 1
PDF Downloads 244 10 1
EPUB Downloads 0 0 0