Chen Tse-YuTaichung Veterans General Hospital, Taiwan
Title: Anterior bone loss after Cervical Baguera C disc versus Bryan disc arthroplasty – Does artificial disc design matter?
Objectives: This study aimed to determine the incidence and risk factors of anterior bone loss (ABL) after cervical disc arthroplasty (CDA) with Baguera C Disc and identify whether design differences between the Baguera C Discs and Bryan Discs affect ABL.
Methods: This was a retrospective study of patients who underwent CDA with one level Baguera C Disc (Spineart, Geneva, Switzerland) at one institution. Radiological measurements, including the extent of ABL, global alignment angle, lordotic angle, shell angle, global range of motion (ROM), and ROM of the index level were recorded. The grading of ABL at the index level was defined as Grade 0, no remodeling; Grade 1, spur disappearance or mild change in body contour; and Grade 2, obvious bone regression with Baguera C Disc exposure.
Results: Combining Grade 1 and Grade 2, ABL was found in 56 upper adjacent vertebra and 52 lower adjacent vertebrae of the 77 patients. Only 18 patients (23.4%) had no ABL. Shell angle was found to differ by Grade 2 ABL in both the upper adjacent level: 0.0 degrees in the Grade 0 and 1 group and 2.0 degrees in the Grade 2 group (p < 0.05); and the lower adjacent level: 0.0 degrees in the Grade 0 and 1 group and 3.5 degrees in the Grade 2 group (p < 0.05). A female predominance of ABL was found.
Conclusions: ABL is more common in Baguera C Disc arthroplasty than Bryan Disc arthroplasty. Larger shell angle was related to ABL after CDA with Baguera C Discs, which may indicate that shell angle is pivotal in determining the incidence of ABL after CDA. The female predominance in ABL with Baguera C Disc arthroplasty might be related to the smaller endplate length as well as the smaller endplate-implant mismatch in females.
Tse-Yu Chen is a outstanding neurosurgeon currently working in Taichung Veterans General Hospital, Taichung, Taiwan. He has been working on the topic of anterior bone loss after cervical disc arthroplasty since his residency. He is also a student studying in Ph.D. Program in Translational Medicine, National Chung Hsing University, Taichung, Taiwan.