Biomechanical Evaluation of Total Disc Replacement Arthroplasty: An In Vitro Human Cadaveric Model

Abstract

Total disc arthroplasty serves as the next frontier in the surgical management of discogenic spinal pathology. The SB Charitè restored motion to the level of the intact segment in flexion-extension and lateral bending and increased motion in axial rotation. The anterior annular resection necessary for device implantation and unconstrained design of the prosthesis account for this change in rotation. The normal lumbar flexion-extension axis of rotation is an ellipse rather than a single point. Only disc replacement rather than pedicle instrumentation or BAK interbody instrumentation preserves the kinematic properties and normal mapping of segmental motion at the operative and adjacent intervertebral disc levels.

Revision of a Charité artificial disc 9.5 years in vivo to a new Charité artificial disc: case report and explant analysis

“…The ideal floating center of rotation (FCR) is 2 mm posterior to the geometric center of the disc space in the sagittal plane [3]. Ideal placement of the center of the Chariteṕ rosthesis is within 3 mm of this point, as described by McAfee et al [7].…”

Analysis of post-operative pain patterns following total lumbar disc replacement: results from fluoroscopically guided spine infiltrations

“…A variety of studies have carefully analyzed the biomechanical properties and motion characteristics of different artificial disc-design prosthesis [12,13,16,17,22,24,25,36,47,50,53,54]. Reported problems associated with TDR include excessive ligament torsions, increased facet pressures, a high risk of instability at the index and adjacent level, up to 2.59 increased load on posterior structures and altered load patterns with sudden rather than gradual load increase in the facet joints [17,39].…”

“…Reported problems associated with TDR include excessive ligament torsions, increased facet pressures, a high risk of instability at the index and adjacent level, up to 2.59 increased load on posterior structures and altered load patterns with sudden rather than gradual load increase in the facet joints [17,39]. Furthermore, it has been shown that TDR with Charité III did not restore the physiological segmental rotational stability with additive destabilising effects for multilevel versus monosegmental TDRs [13,47].…”

The development of a dynamic, six-axis spine simulator

“…11 12 Stiffness matrix testing can characterise the mechanical behaviour of spinal specimens in six degrees 13 of freedom using a position-based control system. There have been numerous studies, often using 14 custom-developed testing machines, that have investigated both the spine, and spinal implants in-15 vitro [7][8][9][10][11]. However, there are few studies that have carried out such experiments in six degrees of 16 freedom [12][13][14][15][16], few that have done so dynamically [17], and none that have characterised the full 17 stiffness matrix dynamically.…”