The spinal cord is the body’s communication superhighway, providing a high-speed connection to and from the command center in our brain. Every organ, muscle, bone, tendon, skin cell, etc. is tied in to this highway through a vast network of nerves that direct movement, carry out reflexes, and report pain, temperature, and that annoying itch that won’t go away. Much of this happens automatically – for example, you don’t have to remember to tell your heart to beat, or your stomach to digest that kale smoothie you just drank. However, if you want to scratch an itch you must voluntarily activate the muscles in your arm and direct its position in space.
Spinal nerve roots are the on/off ramps off the superhighway, and carry information to/from your arms and legs. There are 7 cervical (neck), 12 thoracic (chest), and 5 lumbar (low back) vertebrae – and at each vertebral level, on each side of your body, a spinal nerve root leaves the spinal cord and connects to a reasonably predictable network of nerves. For example, the beach workout my college roommate did 14 times per week (biceps & pecs) is driven by the 6th cervical nerve root; the 10th thoracic nerve root tells you that belly-button piercing hurts (second hand knowledge); and the 4th lumbar nerve root allows my 2 ½ year old son to kick the wall in frustration (quadriceps) when we try to get him to bathe.
When a nerve isn’t working correctly that’s generically referred to as neuropathy – and there are numerous potential causes, including trauma, infection, medication, toxins, medical illness, etc.
Radiculopathy, from the Latin “radix” meaning root, is a specific type of neuropathy caused by compression of the nerve root as it exits the spinal cord. This can manifest as some combination of pain, numbness, and weakness – and in the case of cervical radiculopathy these symptoms are primarily in the upper extremity, such as the neck.
So how/why does a cervical nerve root get compressed?
Broken bones and dislocations aside, the majority of nerve compression is directly or indirectly due to the intervertebral disc. I remember prior to medical school hearing of “discs” in our necks and backs and envisioning something more akin to disc brakes. But in its simplest and most common description, the intervertebral disc is a jelly-donut like structure that connects each of our vertebral bodies. It provides not only shock absorption for the spine, but in a quite complex fashion facilitates and regulates the many different motions of the spine.
As we all age, so age our discs – which starts with dehydration and sets off a cascade of events that can lead to nerve root compression. Disc dehydration can weaken the outer ring of the “donut”, allowing the jelly to bulge or more dramatically squirt out (herniate) and compress the nerve roots. Enough force can even cause a well-hydrated disc to herniate – so it’s not uncommon to see someone in their 20’s or 30’s with cervical radiculopathy after a traumatic event.
Additionally, disc dehydration changes the way the disc moves and the way it resists motion. These new/altered motions over time can lead to arthritis of the joints of the spine, and the enlarged arthritic joints can also directly compress nerve roots leading to radiculopathy.
How is cervical radiculopathy diagnosed?
Diagnosis of cervical radiculopathy is based on a combination of physical examination and imaging of the spine.
Physical examination will often show altered sensation, reflexes, or strength in the upper extremities; and certain neck motions may reproduce symptoms. X-rays can show arthritic changes and alterations in alignment or motion. MRI (magnetic resonance imaging) is best for visualizing compression of the nerve roots. Additional nerve tests may be helpful to confirm a radiculopathy or rule out alternative diagnoses.
How is cervical radiculopathy treated?
Initial treatment of cervical radiculopathy is most often non-operative, and is successful in the vast majority (~90%) of cases.
Treatments can include anti-inflammatory or other medications, physical therapy, cervical traction, epidural steroid injections, and good ‘ole fashioned time – to allow the disc to resorb, and the nerve to adjust to its new environment. If surgery is necessary, because of persistent pain or significant or progressive weakness, the most common surgery performed is called an anterior cervical discectomy and fusion (aka ACDF). Depending on the specific circumstances, your surgeon may consider cervical disc replacement, or alternatively an approach from the back of the neck.
ACDF involves an incision in the front of the neck, which allows for access to and removal of the disc and arthritic bone, which takes the pressure off of the affected spinal nerve root. A bone shim, most commonly from the cadaver bone bank, is then put in place of the disc. A titanium plate and screws are then inserted to span and stabilize the two vertebrae and help them fuse together.
The procedure takes 1-2 hours, may require an overnight stay in the hospital, and is 80-90 percent successful at alleviating arm and, to a lesser extent, neck pain.
Recovery from surgery is relatively quick – most patients experience temporary difficulty swallowing, and require pain medications for a week or two. While there is often restriction of heavy activity in the months it takes for the bones to solidly fuse, most patients are feeling back to “normal” within a month or so after surgery.
Other common conditions that can mimic cervical radiculopathy include nerve root compression elsewhere in the arm (e.g. carpal tunnel syndrome), or disorders of the shoulder (e.g. rotator cuff tear). Rarely, more serious medical or systemic conditions can mimic cervical radiculopathy. If you are having symptoms of upper extremity pain, numbness, or weakness it is recommended that you be evaluated by a medical professional.
David Lunardini, MD, is an orthopedic spine surgeon at the University of Vermont Medical Center and associate professor at the Larner College of Medicine at UVM.