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Patients retained 7º mean angular motion with CDR device at 7-year follow-up
PHOENIX — Patients who underwent cervical disc replacement returned to work 20 days earlier than similar patients who were fused, according to data presented here at Spine Summit 2015: CNS/AANS Section on Disorders of the Spine & Peripheral Nerves Annual Meeting.
Mark E. Shaffrey, MD, FAANS, FACS, presented the findings of a study that compared outcomes of 280 patients who received the Medtronic Prestige LP cervical disc replacement to historical controls treated with anterior cervical discectomy and fusion or ACDF.
The researchers found patients who had cervical disc replacement (CDR) returned to work at 40 postoperative days compared to 60 postoperative days for patients who were fused. According to Shaffrey, other findings showed similar success with treatment between the groups at long-term follow-up, including resolution of arm pain.
Mark E. Shaffrey
For disc replacement patients, “the mean angular motion measurements at the target level were approximately 7º and of course, the ACDF did its job as well with minimum motion over a period of 7 years,” he said.
The analysis of the study data for the patients who received the investigational prosthesis and the fusion patients was done independently at Vanderbilt University. The historical controls were from a different study with the same inclusion and exclusion criteria, he said.
The Neck Disability Index (NDI), one key factor looked in the study, was greater than or equal to 30 at baseline and it improved 15 points from preoperative.
“You can see there was a difference between the investigational arm and the control arm, but overall what we saw was a probability of noninferiority at 100%,” Shaffrey said when he discussed NDI results.
One advantage of the long-term follow-up from this study, he said, was it shed light on outcomes such as revisions and reoperations that just are not yet available with other studies of cervical disc replacement.
“We looked at revisions, which were a modification of original device, for instance putting in a longer screw in a plate, device removal both electively and necessary removals, supplemental fixations and reoperations, which would include things like foraminotomies at the level or adjacent level and what we saw was a difference overall in the percentage of patients that required index levels reoperations – approximately 11% for the ACDF group and approximately 6.5% for the investigational arm,” Shaffrey said.
He noted there were some small, but not statistically significant, differences between the groups, including heterotopic ossification bridging bone that increased by about 10% through the last follow-up.
“We do not know how that affects the device performance,” Shaffrey said. — by Susan M. Rapp
Reference:
Shaffrey ME, et al. Oral paper #106. Presented at: Spine Summit 2015: CNS/AANS Section on Disorders of the Spine & Peripheral Nerves Annual Meeting; March 4-7, 2015; Phoenix.
Disclosure: Shaffrey reports no relevant financial disclosures.