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Kinematic analysis following implantation of the PRESTIGE LP

Izabela Kowalczyk, BHSc,1,2 Navjot Chaudhary, MD,3 Neil Duggal, MD, MSc, FRCS(C)3,4

1Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada 2Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada 3Division of Neurosurgery, London Health Sciences Center, London, Ontario, Canada 4Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada

Abstract 

Background

The clinical success of cervical arthroplasty hinges on the ability to preserve or improve the biomechanics of the functional spinal unit. The purpose of this study was to conduct a radiologic assessment of kinematic parameters preimplantation and postimplantation of the PRESTIGE LP Cervical Disc System (Medtronic, Memphis, Tennessee).

Methods

A total of 120 radiographs of 20 patients following single-level implantation of the PRESTIGE LP were retrospectively reviewed. Static and dynamic radiologic assessments were performed before surgery and at 1 year postoperation. Kinematic parameters including range of motion (ROM), horizontal translation, center of rotation (COR X, Y), anterior disc height and posterior disc height, and disc angle and shell angle were assessed for each spinal level using quantitative motion analysis software. Clinical outcomes were assessed using the short form health survey physical component scores and mental component scores.

Results

The mean physical component scores and mental component scores of the short form health survey (SF-36) improved significantly following surgery. At 1 year postoperation, ROM, translation, and COR X were preserved. The COR Y shifted superiorly from 3.17 ± 2.08mm preoperation to 0.98 ± 2.23mm postoperation (P < .001). The anterior disc height and posterior disc height were significantly increased following surgery (3.97 ± 1.01 to 4.78 ± 1.11mm and 3.04 ± 0.69 to 3.66 ± 0.61mm, respectively; P < .01). The preoperative disc angle was 3.32° ± 2.92° and the postoperative shell angle was 1.11° ± 4.29°, with a mean change of −2.22° ± 4.63° (P < .05).

Conclusions

The PRESTIGE LP maintained preoperative ROM, translation, and COR X values. The postoperative COR Y value changed significantly by shifting superiorly, accompanied by an increase in DH. There was a loss of lordosis at the level of surgery, with the PRESTIGE LP endplates having an almost parallel endplate configuration.

keywords: 
cervical arthroplasty, Cervical disc prosthesis, PRESTIGE LP, total disc replacement, kinematics, range of motion
Volume 7
doi: 
10.1016/j.ijsp.2013.10.003