The viscoelastic cervical disk prosthesis CP-ESP is an innovative one-piece deformable but cohesive interbody spacer. It is an evolution of the LP-ESP lumbar disk implanted since 2006. The implant provides 6 full degrees of freedom including shock absorption. The design allows a limitation for rotation and translation with resistance to motion (elastic return property) aimed at avoiding overload of the posterior facets. The rotation center can vary freely during motion. It thus differs substantially from current prostheses. This study reports the clinical results of a prospective observational study series of 89 patients who are representative of the current use of the ESP implant since 2012. The radiological results are focused on the evolution of the mean center of rotation (MCR) as an additional information to the range of motion (ROM) for the evaluation of the quality of spine movement. 89 patients (33 males, mean age 45 years [28–60], 107 implants) were included for an open, prospective and non-randomized study between October 2012 and December 2015. One level patients were at C3C4 (3), C4C5 (3), C5C6 (41) C6C7 (24) C7T1 (1) Two levels patients were C4C5/C5C6 (3), C5C6/C6C7 (12), C6C7/C7D1 (1) and 3 levels C4C5/C5C6/C6C7 (1)Introduction
Materials and Methods
The viscoelastic cervical disk prosthesis ESP is an innovative one-piece deformable but cohesive interbody spacer. It is an evolution of the LP ESP lumbar disk implanted since 2006. CP ESP provides 6 full degrees of freedom about the 3 axes including shock absorption. The prosthesis geometry allows limited rotation and translation with resistance to motion (elastic return property) aimed at avoiding overload of the posterior facets. The rotation center can vary freely during motion (figure 1) It thus differs substantially from current prostheses. This study reports the results of a prospective series of 49 patients who are representative of the current use of the ESP implant since 2012. The surgeries were performed by 3 senior surgeons. There were 34 women and 15 men in this group. The average age was 44±7 (32–59). The implantation was single level in 78 % of cases. 55 CP ESP prostheses were analyzed. Clinical data and X-rays were collected at the preoperative time and at 3, 6, and 12 months post-op. The functional results were measured using Neck and Arm VAS, NDI, SF-36, (physical componentPCS and mental component MCS). The analysis was performed by a single observer who was independent from the selection of patients and from the surgical procedure.Introduction
Material and methods
