3 minute read
Cervical Disc Replacement M6
By Javier Reto, MD
Neck pain occurs in approximately 2 out of every 3 adults throughout their lifetime and chronically in 15% of the population at any one time. As a result, treatments for neck pain have become increasingly utilized. Thankfully, the vast majority of folks that experience neck pains recover uneventfully. For the subset that require further assistance, physical therapy and over the counter anti-inflammatory medicines, e.g. ibuprofen, naproxen may be necessary to aid in recovery. Interventions such as injections and prescription medications typically become next-step options if needed. Finally, we consider surgery for those unfortunate enough to fail all measures.
There are a significant number of younger people identified, typically falling into 20-50 age range, that become surgical candidates. In the past, these folks were given the option of living with the pain, repeat injections or neck fusion surgery. Neck fusions, where two adjacent vertebra are fused together with intervening disc entirely removed, have been a time-proven and quite successful option for reducing or eliminating pain. However, these surgeries come at the expense of eliminating motion at the particular level or levels involved. In the long run, the loss of motion increases stresses at adjacent disc levels and can lead to more surgery in 20-30% of patients.
Cervical Disc Replacement surgery is an alternative surgical option for those with little to no arthritis with the added benefit of preserving motion and thus potentially reducing the incidence of disc breakdown at adjacent levels.
The last few years have seen several cervical disc replacement options come to market. While they all exhibit motion-preservation technology the manner in which this is accomplished varies and can significantly impact their overall effectiveness. Keep in mind that the ultimate goal of any disc replacement device is to reproduce normal spinal motion or kinetics. But what defines normal, and how is this measured? Luckily for us, spinal kinetics have been well-studied and a few guiding principles have been identified. A well-functioning device should have the ability to mimic normal motion in all normal anatomic parameters. It serves no good purpose for an implant to allow 360 degrees of rotation as humans are not owls! Likewise an implant that allows less than normal motion is restrictive and will result in early wear and likely failure. Normal neck motion is 80-90 degrees of forward bending, 70 degrees of backward bending, 20- 45 degrees of side to side bending, and up to 90 degrees of side to side rotation, as well as abc vertical distraction/ contraction. Most disc replacement options do a good job at reproducing the majority of normal neck movements, but do not necessarily cover all the movements well.
The Orthofix M6 device has been out in the European market since 2006 and in the US market recently in 2019. I was the first surgeon to implant the M6 last August and chose to use it because of its promising characteristics. Laboratory testing has shown that it does among the best at hitting all ranges of normal motion well, including the up and down distraction/contraction movement. It has a shock-absorbing center (nucleus) and outer wall (annulus) that work together to replicate the controlled range of movement and cushioning effect of the natural disc.
Ultimately the goal is to fit the surgical solution to the specific pathology as opposed to one size-fits-all approach. For those that are identified as appropriate candidates, the cervical disc replacement device can be a wonderful option. If you have on-going significant neck or arm pains it would be wise to consult with a spine specialist about the right options for you.
Javier Reto, MD, was the first surgeon in Alabama to implant the M6 artificial disc replacement for the cervical spine.
