Nucleus replacement with the DASCOR disc arthroplasty device: interim two-year efficacy and safety results from two prospective, non-randomized multicenter European studies.

Study Design: A prospective, nonrandomized multicenter study of lumbar disc nucleus replacement using the DASCOR Disc Arthroplasty Device. An interim analysis of clinical results is presented, obtained from European patients enrolled in 2 studies.
Objective: To determine the safety and efficacy of the DASCOR Device for the treatment of symptomatic single-level degenerative disc disease (DDD).
Summary of Background Data: Patients suffering from DDD have been limited to a choice between nonoperative therapies or invasive surgical treatments such as total disc replacement or spinal fusion. The DASCOR Device was developed to provide an alternative treatment with a less invasive surgical intervention.
Methods: A total of 85 patients from 11 European centers were enrolled in 1 of 2 studies between February 2003 and July 31, 2007. Data were collected before surgery and after surgery at 6 weeks and at 3, 6, 12, and 24 months. The clinical outcome measures were obtained from the Visual Analog Scale (VAS) for back pain, the Oswestry Disability Index (ODI), radiographic assessments, and records of analgesic medication use.
Results: Mean VAS and ODI scores improved significantly after 6 weeks and throughout the 2 years. Radiographic results demonstrated, at a minimum, maintenance of disc height with no device expulsion and, despite Modic-Type 1 changes, no subsidence. Fourteen patients had serious adverse events including device explants in 7 patients (7 of 85), in which the main complication was resumed back pain after time. Patients' rate of analgesic medication decreased dramatically over time, with all patients experiencing significant improvements after 3 months and nearly no analgesic medication or narcotic drug use at 2 years.
Conclusion: The interim outcomes showed significant improvements in mean ODI and VAS scores. The results of these European studies suggest that the DASCOR Device may be a safe and effective less-invasive surgical option for patients with DDD.