Biomechanical rigidity of an all-polyetheretherketone anterior thoracolumbar spinal reconstruction construct: an in vitro corpectomy model.
BACKGROUND
Polyetheretherketone (PEEK) is gaining favor as a spinal implant material for interbody and corpectomy cages as well as stabilizing rods. However, there has been little correlation to a relevant and reproducible clinical model. Biomechanical data on PEEK rod constructs have not been reported.


OBJECTIVE
To quantify the stabilizing effects of PEEK versus titanium (Ti) instrumentation in a thoracolumbar corpectomy model.


METHODS
Corpectomy and randomized instrumentation with an all-Ti, all-PEEK, and hybrid cage/rod construct were performed on cadaveric spines to assess biomechanical differences.


METHODS
Pure unconstrained bending moments were applied to the intact spine and subsequent test constructs in the three physiologic planes using a load control protocol. Motion tracking and analysis were carried out to quantify and compare the range of motion (ROM) between different test constructs in each plane.


RESULTS
Flexion ROM did not show significant changes compared with intact, whereas the all-Ti and hybrid construct reduced ROM significantly in extension. Lateral bending was significantly reduced in all the treatment groups. Rotational stability of the construct was significantly compromised by an all-PEEK spinal construct.


CONCLUSIONS
The rigidity of the corpectomy construct increased as the amount of Ti in the construct increased. A hybrid construct incorporating a PEEK corpectomy cage and Ti rods may provide adequate stability for an anterior thoracolumbar reconstruction in the sagittal and coronal planes. An all-PEEK construct may provide adequate stability in the coronal and sagittal planes but may compromise the stability significantly in axial rotation. Consideration should be given for supplemental posterior instrumentation if an all-PEEK construct is used in an anterior thoracolumbar spinal reconstruction procedure.
Moon
Seung-Myung
SM
Department of Neurosurgery, Hangang Sacred Heart Hospital, Hallym University, Yeongdeungpo-dong, Seoul, South Korea.
Ingalhalikar
Aditya
A
Highsmith
Jason M
JM
Vaccaro
Alexander R
AR
D001577:Benzophenones; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D001864:Bone Wires; D015194:Diffusion Chambers, Culture / Q000295:instrumentation* / Q000379:methods*; D017586:Diskectomy / Q000295:instrumentation*; D006801:Humans; D066298:In Vitro Techniques; D007659:Ketones; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D011092:Polyethylene Glycols; D011108:Polymers; D011859:Radiography; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures / Q000295:instrumentation; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D016474:Weight-Bearing
D001577:Benzophenones; D001672:Biocompatible Materials; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols