A new option for neck surgery
Implanting artificial parts of the body in humans once seemed like science fiction, but today it’s routine. That’s especially true for treating certain orthopedic problems, with legions of men and women able to walk with ease thanks to artificial knees and hips, for instance. Now some patients with chronic, often-disabling symptoms caused by a herniated cervical disc can opt for a man-made replacement, known as the Mobi-C disc.
Take Nicole Wellbeloved, who first noticed tingling in her right arm that traveled down to her thumb and index finger in January 2018. Then, one night, Wellbeloved, 45, of Cotuit, tried grabbing a cup of water with her left hand and it dropped to the floor.
“My hands were very weak. I could barely squeeze my toothpaste,” she said.
That’s frightening for anyone, but literally losing her grip was a major problem for Wellbeloved, since she runs Wellbeloved Wellness, a fitness studio in Marstons Mills, as well as several other businesses. Teaching yoga and barre (a workout that combines movement, stretching, weight training and other elements) became impossible.
Doctors eventually determined that Wellbeloved had a pair of cervical discs that were impinging nerves. Discs are cushion-like pads that sit between the seven vertebrae that form the neck portion of the spine. Like all spinal discs, a pad in the cervical region can become herniated, meaning the outer shell cracks and allows the jelly-like material inside to spill out and compress nerves. That can result in persistent pain, numbness and tingling in the shoulders, arms and fingers, with or without accompanying symptoms in the neck.
When Conservative Measures Fail
When conservative measures such as physical therapy and steroid injections fail to relieve symptoms of a herniated cervical disc, surgery is often the next step. The conventional approach to repairing a herniated cervical disc is a procedure called anterior cervical discectomy and fusion (ACDF). Entering through a small incision (usually in the front of the neck), a surgeon removes part or all of the bulging disc. The empty space is filled with donor bone or other material, then the vertebrae above and below where the herniated disc was removed are fused together with screws and a plate.
ACDF is an effective solution for herniated cervical discs, but the fusing of vertebra takes several months and may modestly limit a patient’s neck mobility, explained Paul Houle, MD, FAANS, a neurological surgeon at Cape Cod Hospital. What’s more, about one in five patients who undergoes ACDF later develops problems in neighboring sections of the spine, a condition known as adjacent segment disease, he said. That’s because when two vertebrae are fused, they transfer stress to adjoining parts of the spine above and below, which can speed up disc degeneration and other problems, producing painful symptoms that may require additional surgery.
“So if you have an operation to fix one problem, you’ve got a 20 percent chance of creating another problem,” said Dr. Houle.
The Mobi-C disc, which was approved by the U.S. Food and Drug Administration in 2013, was designed to preserve natural neck mobility and reduce the need for follow-up surgeries. The device, which is implanted in an outpatient procedure, is made of two metal plates that form a sandwich around a flat plastic insert. The plates have teeth that press into the vertebrae above and below, holding the device in place. The plastic insert slides and twists across the bottom plate, allowing the Mobi-C to mimic the movement of a healthy natural disc.
“If you have normal motion, you don’t put increased stress on the adjacent levels of the spine,” said Dr. Houle. That may explain why patients who receive the Mobi-C are significantly less likely than those who undergo ACDF to require additional surgery in the future, which was the finding of a seven-year study published in the International Journal of Spine Surgery in 2018. The study also found that patients who got the Mobi-C maintained good range of motion in their necks.
Who Is a Candidate?
There are limitations on who can receive a Mobi-C disc. A good candidate is a man or woman with a cervical disc that has herniated, but has otherwise not degenerated, that is, become significantly thinner. (If a disc has lost half or more of its height, the patient can’t opt for the Mobi-C.) Also, patients who have developed bone spurs (bony growths that form near joints) in their neck joints due to osteoarthritis are not candidates for Mobi-C.
For patients who do have the Mobi-C implanted, an important benefit is a speedy recovery. Following ADCF, patients have to take it easy for about six weeks, compared to two weeks, on average, for those who receive the Mobi-C. Bouncing back faster appealed to Wellbeloved when Dr. Houle recommended Mobi-C, so she elected to have her two damaged cervical discs replaced with the implants in an operation Dr. Houle performed in November 2018.
As Wellbeloved lay in a hospital bed following the surgery, her husband, Blair, made a request: Squeeze my hand. She responded with a firm clasp. A month later Wellbeloved was gaining more mobility in her neck and eagerly awaiting her chance to get back to work in her fitness studio.
“I’m counting down the days,” she said. “I’m not a ‘sit around’ type of person.”