Study Design. A prospective, randomized, multicenter, Food and Drug Administration-regulated Investigational Device Exemption clinical trial.
Objective. To evaluate the safety and effectiveness of the ProDisc®-L (Synthes Spine, West Chester, PA) lumbar total disc replacement compared to circumferential spinal fusion for the treatment of discogenic pain at 1 vertebral level between L3 and S1.
Summary of Background Data. As part of the Investigational Device Exemption clinical trial, favorable single center results of lumbar total disc replacement with the ProDisc®-L have been reported previously.
Methods. Two hundred eighty-six (286) patients were treated on protocol. Patients were evaluated before and after surgery, at 6 weeks, 3, 6, 12, 18, and 24 months. Evaluation at each visit included patient self-assessments, physical and neurologic examinations, and radiographic evaluation.
Results. Safety of ProDisc®-L implantation was demonstrated with 0% major complications. At 24 months, 91.8% of investigational and 84.5% of control patients reported improvement in the Oswestry Low Back Pain Disability Questionnaire (Oswestry Disability Index [ODI]) from preoperative levels, and 77.2% of investigational and 64.8% of control patients met the ≥15% Oswestry Disability Index improvement criteria. Overall neurologic success in the investigational group was superior to the control group (91.2% investigational and 81.4% control; P = 0.0341). At 6 weeks and 3 months follow-up time points, the ProDisc®-L patients recorded SF-36 Health Survey scores significantly higher than the control group (P = 0.018, P = 0.0036, respectively). The visual analog scale pain assessment showed statistically significant improvement from preoperative levels regardless of treatment (P < 0.0001). Visual analog scale patient satisfaction at 24 months showed a statistically significant difference favoring investigational patients over the control group (P = 0.015). Radiographic range of motion was maintained within a normal functional range in 93.7% of investigational patients and averaged 7.7°.
Conclusions. ProDisc®-L has been found to be safe and efficacious. In properly chosen patients, ProDisc®-L has been shown to be superior to circumferential fusion by multiple clinical criteria.