[First experience and preliminary clinical results with the cervical disc replacement DISCOVER].

Aim: The Discover (DePuy Spine, Raynham, MA, USA) is a newly developed device for cervical disc replacement that is available since 2007 in the EU. To date there are no clinical studies on the Discover. Preliminary clinical and intraoperative results from a pilot study should be compared with data for other commonly used prostheses.

Method: In a prospective study 70 patients underwent cervical disc surgery in 2007. Clinical parameters were the neck disability index (NDI), VAS for neck and arm pain and neurological deficits. The segmental angles were determined by Cobb's method preoperatively and after 12 months. Intraoperative parameters like time of surgery and blood loss as well as complications during the postoperative course were recorded. Clinical controls after 8 weeks, 6 and 12 months were done.

Results: Mean age was 44.3 years. In total, 101 devices in 70 patients (27 two level, 2 three level) were implanted. Average time for surgery amounted to 68 minutes per patient and 54 minutes per prosthesis. Average blood loss was 80 mL. There were no intraoperative complications. All patients, except for 3 surgical revisions, were examined clinically and radiologically after 8 weeks, 6 and 12 months. Study parameters like NDI and VAS for arm and neck pain showed a significant (p < 0.001) improvement at all follow-ups compared to the preoperative situation. However, the value of VAS for arm pain in the follow-up rose again significantly (p < 0.05). The motor deficit improved in 33% completely and in 67% incompletely. Sensory disturbances were unchanged in 17%, improved in 73% and completely resolved in 10%. The average segmental angle improved from 3.1 degrees preoperatively to 5.3 degrees (p < 0.05) after 12 months. Up to the end of the follow-up 8.6% complications were recorded. These were 1 temporary dysphonia and 3 surgical revisions due to translations of the devices (4.3%) and 2 heterotopic ossifications (2.8%).

Conclusion: This is the first study on the Discover. The results of clinical scores, intraoperative data and complications are encouraging and comparable to those from other commonly used types of cervical disc replacement. Regarding the duration of surgery, the correction of segmental angle and the amount of heterotopic ossifications, the Discover proved to be advantageous. However, for a definitive evaluation the follow-up period is still too short.