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Minerva Ortopedica e Traumatologica 2007 August;58(4):303-21

Copyright © 2007 EDIZIONI MINERVA MEDICA

language: English

Biomechanical aspects associated with cervical spine instrumentation and arthroplasty

Santoni B. G., Puttlitz C. M.

Orthopaedic Bioengineering Research Laboratory Department of Mechanical Engineering Colorado State University Fort Collins, CO, USA

Spinal arthrodesis is a versatile and effective option in the management of radiculopathy or myelopathy, congenital deformities, trauma, inflammatory conditions, and neoplasms. Owing much of its success to the compilation and publication of normal cervical spine kinematic data, along with the advent of standard spine in vitro biomechanical testing protocols, instrumentation in the occipitocervical, atlantoaxial, subaxial and cervicothoracic regions of the cervical spine has evolved from innovative, yet crude wiring techniques to rigid screw/plate and screw/rod methods of fixation. These contemporary constructs have obviated the need for postsurgical immobilization and prolonged bed rest while promoting an environment that is biomechanically conducive to fusion and a successful clinical outcome. However, an increasing body of biomechanical and clinical evidence suggests that the relative immobility of fused spinal segments alters stress transfer leading to adjacent-level degeneration. The development of motion-sparing prostheses in the cervical spine has been driven by increasing concerns regarding these arthrodesis-related morbidities, including donor site morbidity, pseudoarthrosis, and adjacent-level degeneration. Though the literature is replete with short- and long-term clinical studies, this review article will highlight the in vitro biomechanical studies that have demonstrated the utility of rigid fixation constructs in cervical spine fusion as well as the more recent human cadaveric studies that have evaluated the ability of motion-sparing prostheses to maintain cervical spine kinetics and kinematics.