Abstract
Introduction
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.
Material and methods
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.
Results
The mean operative time was 48 min (SD: 10 min). We did not observe device-related specific complications.
All clinical outcomes significantly improved at every time points when compared to the pre-operative status (table 1). In the series, 86 % of patients had a good or excellent result at 3 months, 78 % at 6 months, and 88 % at 12 months.
Conclusion
The concept of the ESP prosthesis is different from that of the articulated devices currently used in the cervical spine. This study reports encouraging clinical results about pain, function, kinematic behavior and ROM.
