The one-to-one randomisation trial compared ACDF with plate to the NeoDisc using patients with no previous surgery at study level but previous fusions were allowed.
There were 31 ACDF patients; nine male and 22 female with 22 non-smokers. The average BMI was 20 and surgery time was 0.68 hours. There were 30 NeoDisc patients; 12 male and 18 female with an average age of 43 and BMI of 25. Twenty three were non-smoking and surgery time was 0.64 hours.
The device, a compliant elastomeric core encased in a polyester jacket with anterior phalanges attached via screw fixation enables complete removal of posterior annulus and longitudinal ligament and “would be characterised as a squishy disc and it has resistance to rotation which is distinctive in comparison to other disc arthroplasties”, said Pettine.
The study had a high percentage of follow-up. For control, baseline was 31, 30 at three months, 25 at one year, 28 at two years. For NeoDisc the baseline was 30, 30 at three months, 28 at one year, and 30 at two years.
NeoDisc results were similar to the FDA IDE results of ProDisc-C and Prestige. FDA clinical success of 71.4% in Control patients and 83.3% in NeoDisc patients. There were no re-operations, no major vascular or neurological complications and a level of maintenance or improvement in neurological status.
Re-operations at two year follow-up for Control patients was five all of which had pseudoarthrosis. For the NeoDisc one patient needed decompression and one patient had endplate erosion, converted to fusion.
“Concerns specific to this disc are: some patients see some endplate radiographic changes. There is some instance of patient developing a slight kyphosis at index levels. The only other disc I know that has this resistance to rotation is the M6 [Artificial Disc],” Pettine concluded.