Abstract
Introduction
The viscoelastic lumbar disk prosthesis ESP is an innovative one-piece deformable but cohesive interbody spacer; it 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. It thus differs substantially from current prostheses. This study reports the results of a prospective series of 120 patients who are representative of the current use of the ESP implant since 2006.
Material and methods
The surgeries were performed by 2 senior surgeons. There were 73 women and 47 men in this group. The average age was 42 (27–60). The average body mass index was 24.2 kg/m2 (18–33). The implantation was single level in 89% of cases. 134 ESP prostheses were analyzed.
Clinical data and X-rays were collected at the preoperative time and at 3, 6, 12, 24, and 36 months post-op.
The functional results were measured using VAS, GHQ 28, ODI, SF-36, (physical component PCS 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 92 min (SD: 49 min). The mean blood loss was 73 cc (SD: 162 cc). 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, 89% of patients had a good or excellent result at 3 months, 88% at 6 and 12 months, and 93% at 24 months.
Conclusion
The concept of the ESP prosthesis is different from that of the articulated devices currently used in the lumbar spine. This study reports encouraging clinical results about pain, function, kinematic behavior and radiological sagittal balance. The results are in accordance with previous data collected since the first cases performed in 2005.
