Arthroplasty Better Than Neck Discectomy/Fusion for Radiculopathy

Daniel M. Keller, PhD

April 19, 2011

April 19, 2011 (Denver, Colorado) — Cervical arthroplasty was associated with a higher rate of neurological success and a lower rate of secondary surgeries than anterior cervical discectomy and fusion (ACDF), Praveen Mummaneni, MD, associate professor of neurological surgery at the University of California–San Francisco, reported here at the American Association of Neurological Surgeons (AANS) 79th Annual Meeting.

Dr. Praveen Mummaneni

ACDF has been used successfully to treat single-level radiculopathy and is associated with both very high patient satisfaction scores and a high rate of arthrodesis, Dr. Mummaneni told meeting attendees. However, it also results in a loss of segmental motion and the possible need for reoperations. Cervical arthroplasty using an artificial disc is an alternative and preserves range of motion.

In a study comparing the 2 methods, Dr. Mummaneni and colleagues found that at 2 years, both techniques yielded excellent surgical results.

The researchers used data on cervical arthroplasty gathered in 3 large, multicenter, noninferiority, prospective, randomized US Food and Drug Administration–approved investigational device exemption studies that compared arthroplasty with single-level ACDF with allograft and plating. Each published trial involved 1 artificial disc: Bryan (Medtronic), Prestige ST (Medtronic), or ProDisc-C (Synthes Spine, Inc). The trials used similar inclusion and exclusion criteria and similar clinical outcomes measures. The investigators analyzed published, as well as previously unpublished, source data from the trials.

The 3 trials included 1213 participants (arthroplasty, n = 621; ACDF, n = 592). There were no statistically significant differences in demographics among the groups. Participants had a mean age of about 43.9 years, and about half were men. Approximately 10% were receiving worker's compensation, and about 7% were involved in litigation. At the 24-month follow-up, 584 (94%) patients who underwent arthroplasty and 515 (86.9%) who had had ACDF were evaluated.

Segmental motion was maintained for the arthroplasty group in each of the 3 individual trials and for the combined data. Preoperative segmental motion was 7.26 ± 4.13 degrees; postoperatively, it was 8.14 ± 4.86 degrees for the combined data. Fusion occurred for 95% of the ACDF group. Measures of neurological success favored arthroplasty (relative risk [RR], 0.595; P = .006).

"The interesting thing that we found was that at 2 years after surgery, your chance of having a repeat operation at the level that was treated, or the level next to the level that was treated, if you had an arthroplasty, was lower than if you had a fusion," Dr. Mummaneni said. "That was new information" (RR, .508 and P = .018 for repeat surgery; surgery for adjacent segment disease, P = .026).

However, there were no statistically significant differences between the arthroplasty and ACDF groups in terms of neck disability index, SF-36 health survey physical component and mental component summary scores, or neck or arm pain scores at 24 months.

Dr. Mummaneni emphasized the importance of patient selection. "The arthroplasty is really for younger patients between the ages of, say, 20 and maybe 50 or so — patients who have good range of motion of their neck, and normal facet joints. If you already have your facet joints with a lot of bone spurs in patients who are 60-plus, you can't restore motion to those patients, because we're not doing anything to the joints in the back," he told Medscape Medical News. "The ones who are candidates for this operation at 1 level [are people who] have normal range of motion going in, and they have neck and arm pain from a herniated disc."

US Food and Drug Administration trials of multilevel arthroplasty are expected to be published next year, using the same devices plus others. "Patients who are undergoing a 2- or 3-level fusion, they really lose a lot of range of motion, and if you can preserve that with an arthroplasty, and it's safe and effective, that would be good to know," Dr. Mummaneni said.

Joseph Cheng, MD, MS, associate professor of neurological surgery and director of the Neurosurgery Spine Program at Vanderbilt University Medical Center in Nashville, Tennessee, who was not involved in the study, commented that it is "really an elegant study overall." He noted that it is different from a meta-analysis, which would be "much more limited" than what the investigators did here, as they went beyond just the published papers and gathered unpublished source data from the trials, as needed, to round out their analyses.

Dr. Mummaneni is a consultant to and has received other financial support from DePuy Spine. He receives royalties from DePuy and Quality Medical Publishing. Dr. Cheng has received honoraria from Synthes, the manufacturer of the ProDisc-C arthroplasty device. The study had no outside funding.

American Association of Neurological Surgeons (AANS) 79th Annual Meeting: Scientific Session II. Presented April 11, 2011.