Researchers report good 24- to 36-month results in ProDisc randomized trial
Compared with fusion, ProDisc lumbar surgery offers shorter operative times, less blood loss.
BERGEN, Norway — After receiving the Prodisc prosthesis (Synthes), many patients reported outcomes as good as or better than lumbar fusion, according to one site’s results from a prospective, randomized clinical trial.
The trial evaluated artificial lumbar disc replacement with the ProDisc implant (Synthes) vs. combined anteroposterior lumbar interbody fusion.
Implanting the ProDisc prosthesis at one or two levels, L3 to S1, had distinct advantages over fusion, such as reduced operative time and blood loss, according to investigators at the Texas Back Institute Research Foundation in Plano, U.S.A.
“Total disc replacement (TDR) with ProDisc was as good or better than 360º fusion,” Donna D. Ohnmeiss, PhD, said. “TDR appears to be a valid alternative to fusion in appropriately selected patients with symptomatic disc degeneration once nonoperative treatment has failed.”
At the International Society for the Study of the Lumbar Spine (ISSLS) 33rd Annual Meeting, Ohnmeiss presented 24- to 36-month results of patients enrolled in the Plano study. To be included, patients had to be 18 to 50 years old and have symptoms that persisted to 6 months that did not resolve with conservative care. Oswestry back scores had to be at least 40.
Investigators excluded patients with previous lumbar fusions, stenosis, osteoporosis, spondylolisthesis greater than grade 1 and major facet problems. They analyzed data for 157 patients with a minimum of 24 months’ follow-up, including 50 patients in the group followed 36 months. In all, 137 patients underwent TDR randomized 2:1 TDR to fusion.
For the ISSLS study, investigators studied only results of randomized patients, 59 with TDR paired with 30 with fusion, and 65 patients in a continued-access arm of the study. They analyzed preop data and postoperative findings at 6 weeks, 3, 6, 12, 18, 24 and 36 months.
This subset of TDR and fusion patients were similar in gender, levels operated, age and body mass index.
By 6 weeks, investigators saw clinically significant improvement in both treatment groups, which was maintained through the 24- and 36-month follow-up. At final follow-up, Visual Analog Scale scores improved 62.5% in the TDR group vs. 44.5% in the fusion group (P<.05). Mean Oswestry scores improved for both groups, although the difference was not statistically significant.
French surgeon Thierry Marnay, MD, designed the ProDisc. It has been implanted in more than 8,000 patients in Europe since late 1999.
For more information:
- Zigler JE, Sachs BL, Rashbaum RF, Ohnmeiss, DD. A prospective, randomized study comparing Prodisc to fusion: 24- to 36-month follow-up. #28. Presented at the International Society for the Study of the Lumbar Spine 33rd Annual Meeting. June 14-17, 2006. Bergen, Norway.
- Orthopaedics Today was unable to determine whether the investigator has a direct financial interest in the product discussed in this article.