Degenerative disc disease is one of the most common causes of low back pain in adults, resulting from inflammation and instability around the affected disc. Traditionally, degenerative disc disease was treated through spinal fusion surgery, which stops the motion at the pain-generating joint. However, recent developments have allowed physicians to localize the affected disc and replace it with an artificial disc, thereby reducing pain while restoring normal spinal motion.
Current artificial disc technologies (Charité, ProDisc-L) rely on sliding surfaces composed of metal, polymer, or ceramic, and the maintenance of motion is dependent on the specific disc design. One concern in the current technologies is the inability to provide adequate shock absorption.
New elastomeric disc replacements, such as the Physio-L Artificial Lumbar Disc, are composed of a compliant polycarbonate-polyurethane core that is designed to mimic physiologic levels of shock absorption and spinal flexibility. A study was conducted to examine the safety and effectiveness of the new disc 12 months after surgery, and to compare these results to those previously obtained in studies of the Charité and ProDisc-L artificial discs. The study, titled "Clinical performance of an elastomeric lumbar disc replacement: Minimum 12 months follow-up," was published by Elsevier in the March 2010 issue of the SAS Journal.
All patients completed the 12-month follow-up evaluations. Through 12 months, the Physio-L devices have remained intact with no evidence of subsidence, migration, or expulsion. VAS low-back pain and ODI scores improved significantly at all follow-up periods compared to preoperative scores. The range of motion of 13.3° ± 5.5° at the index level was considered normal. Overall, patients were satisfied with an average score of 83.5 ± 26.8 mm. When comparing the device to other artificial discs, the current device showed a clinically relevant improvement in both ODI and VAS scores at all follow-up time points. Statistically significant improvements in both scores were observed at 12 months (P < .05).
The Physio-L is safe and efficacious, as demonstrated by improved pain relief and functional recovery without any implant failures, significant device related complications, or adverse incidents. The clinical results for VAS and ODI were superior to other marketed artificial lumbar discs such as the Charité and ProDisc-L at the same follow-up timeframes.
The study documented outcomes for 12 patients, all of whom received either a one or two-level implantation of the Physio-L artificial disc between March and August 2007. Patient outcomes were measured using the Oswestry disability index (ODI), the visual analog scale for back pain (VAS), and the Short Form 36 Health Survey Questionnaire (SF-36, a quality of life measure). Patient self-assessments showed a statistically significant (P < 0.05) improvement at 12 months in both ODI and VAS scores following surgery; an increase was seen in physical and mental components of SF-36 scores, indicating that patient quality of life had improved.
These scores were compared to previous scores from patients with the Charité and ProDisc-L artificial discs. Outcomes of all three procedures were measured using the same indices. Compared to the other treatments, Physio-L showed superior improvement in ODI and VAS scores in the same follow-up time frames.
Physical examinations revealed maintenance of normal range of motion along with restoration of the disc height. All patients showed improved pain relief and function, and were able to return to work with little or no restrictions. Of the 12 patients surveyed, 10 would recommend this treatment to others.