Faculty Collaboration Database

Differences in spinal cord biomechanics after laminectomy, laminoplasty, and laminectomy with fusion for degenerative cervical myelopathy. J Neurosurg Spine 2023 Jul 01;39(1):28-39

Date

04/09/2023

Pubmed ID

37029671

DOI

10.3171/2023.3.SPINE2340

Scopus ID

2-s2.0-85164233516 (requires institutional sign-in at Scopus site)   1 Citation

Abstract

OBJECTIVE: Spinal cord stress/strain during neck motion contributes to spinal cord dysfunction in degenerative cervical myelopathy (DCM), yet the effect of surgery on spinal cord biomechanics is unknown. It is expected that motion-preserving and fusion surgeries for DCM will have distinct effects on spinal cord biomechanics. The aim of this study was to compare changes in spinal cord biomechanics after laminectomy with fusion, laminectomy, and laminoplasty using a patient-specific finite element model (FEM) for DCM.

METHODS: A patient-specific FEM of the cervical spine and spinal cord was created using MRI from a subject with mild DCM. Multilevel laminectomy with fusion, laminectomy, and laminoplasty were simulated for DCM using the patient-specific FEM. Spinal cord von Mises stress and maximum principal strain during neck flexion-extension, lateral bending, and axial rotation were recorded. Segmental range of motion, intradiscal pressure, and capsular ligament strain were also measured. FEM outputs were calculated as a change with respect to the preoperative values and compared between the three models.

RESULTS: Across the surgical levels, spinal cord stress increased after laminectomy for neck flexion (+50%), neck extension (+37.8%), and axial rotation (+23%). Similarly, spinal cord strain increased in neck extension (+118.4%) and axial rotation (+75.1%) after laminectomy. Laminoplasty was associated with greater spinal cord stress in neck flexion (+57.4%) and increased strain in lateral bending (+56.7%) and axial rotation (+20.9%). Compared with laminectomy and laminoplasty, spinal cord biomechanics for laminectomy with fusion revealed significantly reduced median extension stress (13.7 kPa vs 9.7 kPa, p = 0.03), lateral bending strain (0.01 vs 0.007, p = 0.007), axial rotation stress (3.7 kPa vs 2.1 kPa, p = 0.04), and axial rotation strain (0.017 vs 0.009, p = 0.04).

CONCLUSIONS: Spinal cord strain decreased in neck flexion in all three models, yet spinal cord stress increased with neck flexion for laminectomy and laminoplasty. Changes in spinal cord biomechanics for laminoplasty parallel those for laminectomy with fusion except during neck flexion, lateral bending, and axial rotation. Compared with motion-preserving approaches such as laminectomy and laminoplasty, laminectomy with fusion was associated with the lowest spinal cord stress and strain in flexion-extension, lateral bending, and axial rotation of the neck.

Author List

Vedantam A, Harinathan B, Warraich A, Budde MD, Yoganandan N

Authors

Matthew Budde PhD Associate Professor in the Neurosurgery department at Medical College of Wisconsin
Aditya Vedantam MD Assistant Professor in the Neurosurgery department at Medical College of Wisconsin
Narayan Yoganandan PhD Professor in the Neurosurgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Biomechanical Phenomena
Cervical Vertebrae
Humans
Laminectomy
Laminoplasty
Range of Motion, Articular
Spinal Cord Diseases
Spinal Fusion