Cervical arthroplasty with Discocerv‰ ''Cervidisc Evolution'' surgical procedure and clinical experience 9 years after the first implantation of the first generation

Long time considered as gold standard in the surgical treatment of the cervical disc disease, anterior discectomy and fusion is, however, associated with an important rate of complications and low quality of life levels, especially in young and active populations. As literature emphasized a correlation between fusion (and the resulting suppression of motion) and adjacent segment degeneration, motion-preserving techniques have been imagined; most of them involve cervical disc prostheses that are under clinical and biomechanical evaluation. Various materials and designs are proposed, with the common point that motion axis is located downwards (with regard to the prosthesis), thus allowing not only a physiologicalmotion in a sagittal plane but also some possible mechanical conflicts between unci and the upper vertebra. Uncus resection may solve the conflict, however, with a great risk of postoperative ossification of bone spurs. For a prosthesis whose motion axis is located upwards, motion in frontal plane is physiological, avoiding the aforementioned mechanical conflict and the need for uncus resection. However, the movements in a sagittal plane may be altered, so we studied such a concept of prosthesis from a clinical and biomechanical point of view. The population consisted in 36 patients who underwent cervical arthroplasty with Discocerv™ “Cervidisc Evolution” for cervical degenerative diseases without instability. Among this group, 21 (8 men, 13 women, mean age: 49 ± 9 years) patients reached the 12-month follow-up. The following data were analyzed — (A) clinical: surgery data, complications, return to work, pain (VAS), function (NDI) and overall outcome (Odom’s criteria); (B) radiological: flexion-extension motion, mean centers of rotation, local and C1–C7 lordosis, signs of degeneration or implant migration. Surgery duration was of 65 ± 15 min and the average hospital stay of 4 days. There were one case of per-operative minor (important bleeding) and three cases of postoperative complications (unrelated to the prosthesis). Twelve months after surgery, an important cervical and radicular pain relief was underlined by postoperative values of respectively 22.6 and 20.3 versus 69.1 and 65.3 observed before surgery. Functional disability diminished from 55.4/100 before surgery to 18.7/100 at 1-year follow-up and 83% of patients declared high levels of satisfaction. These findings are in agreement with Odom’s criteria showing 76% of excellent and 24% of good results, 12 months after surgery, and with the good return to work rate (83% of patients resumed their previous activities within 6 months). Radiological analysis showed preserved motion for the treated level (average: 9.2 ± 4°) and adjacent ones at 12 months, with normal centers of rotation in 64% of cases (in all postoperative examinations) and altered but stable in 36% of cases, where motion axis was located more on the superior plate of the prosthesis. A statistically significant difference between pre- and postoperative values of local lordosis showed a restoration of sagittal alignment. Moreover the absence of a significant postoperative evolution as well as the statistically significant differences between long-term post-and preoperative values of C1–C7 lordosis confirmed this progressive realignment. The findings of this ongoing prospective study highlighted encouraging preliminary results suggesting the efficacy of the device in symptoms relief and motion preservation. Nevertheless, they need to be validated by the long-term results, which will clearly show if the device is able to maintain motion while preventing adjacent segment disease.