Still relatively new, the first FDA approvals for cervical artificial disc replacement (ADR) were handed down in 2007 in the United States. Less than a decade later, the arthroplasty options continue to grow as surgeons increasingly favor the more natural movement afforded by the discs over traditional fusion surgery in cases where ADR is an option.
"For many years, the gold standard of care for cervical disc herniation was anterior cervical discectomy and fusion (ACDF)," explained Colin G. Crosby, MD, an orthopaedic spine surgeon with Elite Sports Medicine and Orthopaedic Center.
However, he continued, "About a quarter of these patients require additional surgery within 10 years because of implications associated with fusion surgery."
Whereas fusion surgery removes the degenerated disc and fuses together two vertebrae for a rigid hold, Crosby said replacing the impacted disc allows surgeons "to preserve motion in the neck, which provides for quicker recovery ... and hopefully, prevention of the need for future surgeries." He added that implants preserve the natural architecture of the cervical vertebrae. With fusion, the rigidity tends to be hard on the levels above and below the fusion, leading to additional cervical breakdown over time and potentially more surgery.
While there are several cervical disk prostheses now approved by the FDA, the Mobi-C® Cervical Disc by LDR Spine was the first ... and until a couple of weeks ago, the only (see box) ... disc approved for both one and two-level indications in the C3-C7 spine. The three-piece design with two Cobalt Chromium alloy endplates and an Ultra High Molecular Weight polyethylene core received FDA approval in August 2013. However, Crosby said it has been only in the last year that the implant has received approval from major insurance carriers in Tennessee.
"In cervical disc arthroplasty, you put in a Mobi-C implant that mimics physiological motion while allowing the surgeon to adequately decompress the spinal cord and/or nerve roots," said Crosby, who has no conflict of interest or ties to LDR.
While nonsurgical treatment plans work for the vast majority of patients with cervical disc pain, ADR or ACDF are options for patients who have failed those more conservative measures and still have pain, weakness and/or numbness radiating down their arm.
One recent success story is Rocky Marvel, drummer for the Bellamy Brothers. An MRI revealed a badly herniated disc. After trying multiple other treatments ranging from massage therapy to steroid shots, Marvel was just about at wit's end. His condition progressed to a point where he found it difficult to even lay down on his left side, let alone perform. This past spring, Crosby inserted the Mobi-C disc. "He had immediate cessation of his pain and numbness and a rapid regaining of his strength," said Crosby. "A little more than two weeks post-operatively, he went to Europe and played a European tour with the Bellamy Brothers ... a little sooner than I would have recommended," Crosby added with a rueful laugh.
ADR comes with the normal surgical risks and is not appropriate for use in individuals with advanced arthritic spines, cervical instability or deformity or those with cervical trauma. In addition, patients with systemic infection or infection at the surgery site, those with known allergy or sensitivity to any material in the artificial disc, or those with low bone density are not good candidates for ADR.
While some surgeons are performing ADR on an outpatient basis, Crosby said he prefers to keep patients overnight for observation. "They often wake up in the recovery room with near complete resolution of their preoperative pain and symptoms," he noted of the procedure, which takes about an hour.
Crosby noted that 10-year data from the original FDA trial for cervical disc arthroplasty in America has shown "good, long-term reduction in pain and decreased need for subsequent surgeries."
He continued, "By preserving normal physiologic motion, we can decrease the long-term negative consequences of fusion surgery."