The effects of muscle weakness on degenerative spondylolisthesis: A finite element study

Background: Whether muscle weakness is a cause, or result, of degenerative spondylolisthesis is not currently well understood. Little biomechanical evidence is available to offer an explanation for the mechanism behind exercise therapy. Therefore, the aim of this study is to investigate the effects of back muscle weakness on degenerative spondylolisthesis and to tease out the biomechanical mechanism of exercise therapy. Methods: A nonlinear 3‐D finite element model of L3–L5 was constructed. Forces representing global back muscles and global abdominal muscles, follower loads and an upper body weight were applied. The force of the global back muscles was reduced to 75%, 50% and 25% to simulate different degrees of back muscle weakness. An additional boundary condition which represented the loads from other muscles after exercise therapy was set up to keep the spine in a neutral standing position. Shear forces, intradiscal pressure, facet joint forces and von Mises equivalent stresses in the annuli were calculated. Findings: The intervertebral rotations of L3–L4 and L4–L5 were within the range of in vitro experimental data. The calculated intradiscal pressure of L4–L5 for standing was 0.57 MPa, which is similar to previous in vivo data. With the back muscles were reduced to 75%, 50% and 25% force, the shear force moved increasingly in a ventral direction. Due to the additional stabilizing force and moment provided by boundary conditions, the shear force varied less than 15%. Interpretation: Reducing the force of global back muscles might lead to, or aggravate, degenerative spondylolisthesis with forward slipping from biomechanical point of view. Exercise therapy may improve the spinal biomechanical environment. However, the intrinsic correlation between back muscle weakness and degenerative spondylolisthesis needs more clinical in vivo study and biomechanical analysis. HighlightsA nonlinear finite element model of L3–L5 was constructed and validated.Muscle loads in an intact situation and weak situation were applied.Back muscle weakness might lead to, or aggravate, degenerative spondylolisthesis.Exercise therapy might improve the biomechanical environment around the spine.

[1]  P. Cripton,et al.  The effect of disc degeneration on anterior shear translation in the lumbar spine , 2015, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[2]  H. Herkowitz.  Spine update. Degenerative lumbar spondylolisthesis. , 1995, Spine.

[3]  Y. E. Kim,et al.  An Analytical Investigation of the Mechanics of Spinal Instrumentation , 1988, Spine.

[4]  H Labelle,et al.  Mechanical loading effects on isthmic spondylolytic lumbar segment: Finite element modelling using a personalised geometry , 2009, Computer methods in biomechanics and biomedical engineering.

[5]  A. Shirazi-Adl,et al.  Investigation of solute concentrations in a 3D model of intervertebral disc , 2009, European Spine Journal.

[6]  Y K Liu,et al.  A three-dimensional nonlinear finite element model of lumbar intervertebral joint in torsion. , 1987, Journal of biomechanical engineering.

[7]  Gunnar B. J. Andersson,et al.  Effects of Slip Severity and Loading Directions on the Stability of Isthmic Spondylolisthesis: A Finite Element Model Study , 2003, Spine.

[8]  L. Claes,et al.  Intradiscal pressure together with anthropometric data--a data set for the validation of models. , 2001, Clinical biomechanics.

[9]  R. Lin,et al.  Differences of lumbosacral kinematics between degenerative and induced spondylolisthetic spine. , 2003, Clinical biomechanics.

[10]  A. Rohlmann,et al.  Considerations when loading spinal finite element models with predicted muscle forces from inverse static analyses. , 2013, Journal of biomechanics.

[11]  A. Rohlmann,et al.  Comparison of four reconstruction methods after total sacrectomy: a finite element study. , 2012, Clinical biomechanics.

[12]  W. Edwards,et al.  Structural features and thickness of the vertebral cortex in the thoracolumbar spine. , 2001, Spine.

[13]  I. Macnab,et al.  Classification of spondylolisis and spondylolisthesis. , 1976, Clinical orthopaedics and related research.

[14]  N. Crawford,et al.  Biomechanics of grade I degenerative lumbar spondylolisthesis. Part 1: in vitro model. , 2001, Journal of neurosurgery.

[15]  Antonius Rohlmann,et al.  Analysis of the influence of disc degeneration on the mechanical behaviour of a lumbar motion segment using the finite element method. , 2006, Journal of biomechanics.

[16]  A Plamondon,et al.  Comparison of trunk muscle forces and spinal loads estimated by two biomechanical models. , 2009, Clinical biomechanics.

[17]  G. Bergmann,et al.  Estimation of muscle forces in the lumbar spine during upper-body inclination. , 2001, Clinical biomechanics.

[18]  N. Langrana,et al.  Role of Ligaments and Facets in Lumbar Spinal Stability , 1995, Spine.

[19]  Guoan Li,et al.  Segmental spinal canal volume in patients with degenerative spondylolisthesis. , 2013, The spine journal : official journal of the North American Spine Society.

[20]  A Rohlmann,et al.  Realistic loading conditions for upper body bending. , 2009, Journal of biomechanics.

[21]  Yoon-Hyuk Kim,et al.  Role of trunk muscles in generating follower load in the lumbar spine of neutral standing posture. , 2008, Journal of biomechanical engineering.

[22]  André Plamondon,et al.  An improved multi-joint EMG-assisted optimization approach to estimate joint and muscle forces in a musculoskeletal model of the lumbar spine. , 2011, Journal of biomechanics.

[23]  V. Goel,et al.  Athletes with Unilateral Spondylolysis are at Risk of Stress Fracture at the Contralateral Pedicle and Pars Interarticularis: A Clinical and Biomechanical Study , 2005, The American journal of sports medicine.

[24]  A Shirazi-Adl,et al.  Mechanical Response of a Lumbar Motion Segment in Axial Torque Alone and Combined with Compression , 1986, Spine.

[25]  V K Goel,et al.  The Pathomechanism of Spondylolytic Spondylolisthesis in Immature Primate Lumbar Spines: In Vitro and Finite Element Assessments , 2001, Spine.

[26]  V K Goel,et al.  A combined finite element and optimization investigation of lumbar spine mechanics with and without muscles. , 1993, Spine.

[27]  O. Friberg.  Instability in spondylolisthesis. , 1991, Orthopedics.

[28]  C. Aubin,et al.  A biomechanical study of L5-S1 low-grade isthmic spondylolisthesis using a personalized finite element model. , 2006, Studies in health technology and informatics.

[29]  M. Parnianpour,et al.  Spinal muscle forces, internal loads and stability in standing under various postures and loads—application of kinematics-based algorithm , 2005, European Spine Journal.

[30]  Antonius Rohlmann,et al.  Discrepancies in anthropometric parameters between different models affect intervertebral rotations when loading finite element models with muscle forces from inverse static analyses , 2014, Biomedizinische Technik. Biomedical engineering.

[31]  H. Herkowitz,et al.  Treatment of instability and spondylolisthesis: surgical versus nonsurgical treatment. , 2006, Clinical orthopaedics and related research.

[32]  Gerhard A. Holzapfel,et al.  An Anisotropic Model for Annulus Tissue and Enhanced Finite Element Analyses of Intact Lumbar Disc Bodies , 2001 .

[33]  M. Devor,et al.  What causes low back pain? , 2009, Pain.

[34]  Y. Morimoto,et al.  Intraoperative Measurement of Lumbar Spinal Instability , 1992, Spine.

[35]  Zheng-Cheng Zhong,et al.  Finite element analysis of the spondylolysis in lumbar spine. , 2006, Bio-medical materials and engineering.

[36]  A. Ghanayem,et al.  Spondylolisthesis and spondylolysis. , 2008, Instructional course lectures.

[37]  T. Kubo,et al.  Investigation of intervertebral disc and facet joint in lumbar spondylolisthesis using T2 mapping. , 2014, Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine.

[38]  Antonius Rohlmann,et al.  Determination of trunk muscle forces for flexion and extension by using a validated finite element model of the lumbar spine and measured in vivo data. , 2006, Journal of biomechanics.

[39]  A. Rohlmann,et al.  Influence of graded facetectomy and laminectomy on spinal biomechanics , 2003, European Spine Journal.

[40]  Mark D. Brown,et al.  Intraoperative Measurement of Lumbar Spine Motion Segment Stiffness , 2002, Spine.

[41]  C. Puttlitz,et al.  Lower cervical spine facet cartilage thickness mapping. , 2008, Osteoarthritis and cartilage.

[42]  M. Panjabi,et al.  Functional Radiographic Diagnosis of the Lumbar Spine: Flexion—Extension and Lateral Bending , 1991, Spine.

[43]  A Rohlmann,et al.  Applying a follower load delivers realistic results for simulating standing. , 2009, Journal of biomechanics.

[44]  D. Hunter,et al.  Diagnosis and conservative management of degenerative lumbar spondylolisthesis , 2007, European Spine Journal.

[45]  T. C. Howard,et al.  Roentgenographic Evaluation of Lumbar Spine Flexion‐Extension in Asymptomatic Individuals , 1989, Spine.

[46]  Christian M. Puttlitz,et al.  Parametric convergence sensitivity and validation of a finite element model of the human lumbar spine , 2011, Computer methods in biomechanics and biomedical engineering.

[47]  J. Frymoyer.  Degenerative Spondylolisthesis: Diagnosis and Treatment , 1994, The Journal of the American Academy of Orthopaedic Surgeons.

[48]  A Rohlmann,et al.  Estimation of trunk muscle forces using the finite element method and in vivo loads measured by telemeterized internal spinal fixation devices. , 1999, Journal of biomechanics.

[49]  K. An,et al.  Biomechanical evaluation of posterior lumbar dynamic stabilization: an in vitro comparison between Universal Clamp and Wallis systems , 2011, European Spine Journal.