Centering of Cervical Disc Replacements Usefulness of Intraoperative Anteroposterior Fluoroscopic Guidance to Center Cervical Disc Replacements: Study on 20 Discocerv (Scient'X Prosthesis)

Study Design. This is a prospective randomized computed tomographic scan study on the centering of cervical disc prosthesis (Discocerv; Scient'X) with and without anteroposterior (AP) fluoroscopic guidance. Objective. Analyze interest of AP fluoroscopic guidance for coronal positioning in cervical disc replacements. Summary of Background Data. This series consisted of 20 patients. One group of 10 patients was operated using only lateral fluoroscopic guidance (L guidance) and the other group of 10 patients was operated using both lateral and AP fluoroscopic guidance (AP + L guidance). Total disc replacements positioning is analyzed in the 2 groups. Methods. All patients had a computed tomographic scan 24 hours after surgery. Specific reconstructions were obtained from the native slices. Three planes P1, P2, and P3 are defined to quantify centering of the prosthesis in axial sagittal and coronal planes. Results. In the coronal plane P1, there is no difference in lateralization between the L guidance (absolute value of average M = 0.93 mm; SD = 0.59 mm) and AP + L guidance groups (M = 1.28 mm; SD = 0.75 mm). In the axial plane, there is no difference in lateralization between the L guidance and AP + L guidance groups. In the L guidance group, average was 1.96 degrees (SD = 1.43 degrees) and 3.18 degrees (SD = 2.94 degrees) in AP + L guidance. There is no significative difference between 2 groups in coronal (P = 0.26) and axial plane (P = 0.19). Conclusion. Unci are reliable landmarks for coronal centering of total disc replacements. AP fluoroscopic guidance does not improve this positioning.