Discrepancy between cervical disc prostheses and anatomical cervical dimensions

Abstract

ObjectiveThe aim of this study was to assess appropriateness of the sizes of available cervical disc prostheses based on tomographic measurement of human cervical vertebrae.MethodsThe anatomic dimensions of the C3–C7 segments were measured on 50 patients (age range 26–47 years) with computerized tomography scan and compared with the sizes of the popular cervical total disc prostheses (CTDP) at the market [Bryan (Medtronic), Prodisc-C (Synthes), Prestige LP (Medtronic), Discover (DePuy)]. The mediolateral and anteriorposterior diameters of the upper and lower endplates were measured with a digital measuring system.ResultsOverall, 43.7% of the largest implant footprints were smaller in the anterior-posterior diameter and 42.6% in the mediolateral diameter were smaller than cervical endplate measurements. Discrepancy of the level C5/C6 and C6/C7 was calculated as 56.2% at the anteroposterior diameter and 43.8% at the center of mediolateral diameter.ConclusionLarge disparity has been found between the sizes of devices and cervical anatomic data.Companies that produce CTDP should take care of the anatomical dimensions and generate different sizes of CTDP. Spine surgeon should be familiar with the size mismatch in CTDP that may affect the clinical and radiological outcome of the surgery.

Does the sizing of current cervical disc arthroplasty systems match Chinese cervical anatomic dimensions?

“…Thus, when selecting an appropriate cervical implant, surgeons should consider patient height as well as estimated normal disc height. Possible reasons for footprint mismatch include the following: first, the footprint dimensions of currently available disk prostheses were derived from early white cadaver data, and anatomic studies illustrated a large discrepancy between the footprint dimensions and anatomic data (Thaler et al, 2013;Karaca et al, 2016). Second, the available prostheses only provide limited choices in the contour footprint dimensions that cannot match various anatomic dimensions.…”