Degenerative Disc Disease in the Neck
Cervical degenerative disc disease is considered part of the natural aging process with discs losing their shock-absorbing abilities, and flexibility, as we get older. Discs in the cervical spine are put under stress and strain every day, with both chronic and acute trauma leading to chronic and acute neck pain. Pain may also be ca
Discs consist of a soft-gel center called the nucleus pulposus surrounded by a fibrous capsule called the annulus fibrosis. The gel-like center can become dry and shrunken over time, and the fibrous outer shell may become brittle and liable to rip or warp, leading to herniation or a bulging disc. Everyone experiences some degree of disc degeneration as they age, but not everyone experiences cervical spine pain. Disc degeneration will generally lead to a narrowing (stenosis) of the cervical spine, with resultant pressure on the structures contained therein, such as the nerves and blood vessels of the neck.
How DDD is Diagnosed
Diagnosis is usually arrived at through the use of x-rays, MRI and CT scans. These can highlight structural abnormalities and show spinal stenosis and compression of the vertebra. The use of selective nerve root blocks may assist physicians in isolating the problematic disc prior to treatment, and frequently provide relief from the associated pain after this diagnostic procedure. Treatments may involve gentle, non-invasive spinal decompression using devices for neck pain relief.
Medications and Treatments
Medications, such as analgesics and anti-inflammatories are usually incorporated into a therapeutic plan, whether these are conventional NSAIDs or natural alternatives for alleviating inflammation and pain. Surgery is usually a last resort for degenerative disc disease, and takes the form of discectomy, disc replacement, spinal fusion, and laminectomy amongst other procedures. As always, surgery has complications and other methods of treatment should be exhausted prior to irreversible surgical intervention.
Causes of Degenerative Disc Disease in the Neck
Simple wear and tear is the usual culprit responsible for cervical degenerative disc disease. Some will suffer more than others due to lifestyle factors and genetic variations which predispose them to more extensive damage on acute and chronic trauma. As the discs between intervertebral bodies begin to degenerate, the whole cervical spine becomes less flexible leading to neck pain and stiffness in the neck and back. Those who practice yoga regularly and long-term are less likely to suffer from severe disc degeneration in the cervical spine compared to those who do not, most likely as result of improved flexibility and strength of the muscles supporting the spine (Jeng, 2010). The effect of long-term yoga practice on the lumbar spine was not considered significant by Jeng (2010), but there was some evidence of benefit in most of the study group.
Acute trauma, such as whiplash, or a contact sports injury, can trigger degenerative changes in the spine, including damage to the discs. The discs are also liable to trauma from twisting as their structure only allows for a certain degree of flexibility in either direction. This is beneficial for maintaining the limits of rotation in the spine, but can lead to damage to the fibers in the disc. The annulus is made up of multiple layers (lamellae) of collagen fibers arranged circumferentially along the edge of the disc. These lamella are oriented at a 30 degree angle to the horizontal axis of the disc and attach at the end plate around the nucleus and the ring apophysis on the outer edge of the disc. The arrangement of fibers in this fashion means that the rotation of the spine is resistant to tension past a certain point as some of the fibers are relaxed and some are stretched depending on the direction of rotation. Clearly, overstretching the spine to one side can cause damage to these fibers as they are stretched beyond their capacity. Trauma such as this can lead to instability in the spine, disc herniation, bulging of the discs, and degenerative disc disease of the cervical spine.
Windsor (2004) states that 36% of all spinal intervertebral disease is accounted for by degeneration of the cervical intervertebral discs (the leading cause is lumbar disc disease which accounts for 62%). By the mid-thirties the degeneration of the discs is usually well underway, with fifty year olds beginning to show degenerative changes in the spine. Gradual narrowing of the spinal canal (stenosis) can remain asymptomatic until myelopathy occurs in some patients. Acute trauma will exacerbate this degeneration. Cervical spondylosis and other degenerative conditions are usually interconnected and can cause problems such as pressure on the nerves exiting the spine leading to radiculopathy. Cervical disc disease with myelopathy is less common than disc degeneration without myelopathy, but both issues can cause neck pain and paraesthesia of the arms, including muscle weakness and problems of sensation. Occasionally the myelopathy extends to affect the legs, the bowel, and the bladder.
Symptoms of Degenerative Disc Disease in the Neck
Degenerative disc disease in the neck can remain asymptomatic in some individuals. In others, the patient may suffer from muscle spasms and tenderness in the cervical spine, pain in the neck, and referred pain and paraesthesia in the arm, chest, head, shoulders, and in the lower body. Acute inflammation can cause flare-ups of symptoms with more pressure put on spinal nerves in an already narrowed cervical spine. As the discs degenerate further the space through which nerves and blood vessels in the cervical spine have to travel is increasingly diminished, making myelopathy a likely outcome. This spinal stenosis and spondylosis can be exacerbated by the growth of osteophytes, and other degenerative changes in the bones, facet joints, and ligaments of the spine.
Disc degeneration leads to stiffness of the neck and back as discs no longer allow the flexibility of movement they did when they were supple and strong. Brittle discs are also more likely to herniate, causing acute pressure in the spine and often resulting in extreme debility and pain. Pain is generally worse at the end of the day, with inflammation and muscle strain building throughout the day for most patients.
Degeneration at different levels of the spine
Different discs produce different patterns of symptoms as they degenerate. For example, a weakening of the C6-C7 disc can cause a pinched nerve at this site that results in wrist-drop and altered sensation in the middle fingers, along with tricep and forearm weakness. Disc degeneration at the C4-C5 cervical spine level will generally produce weakness in the deltoid muscles and possible shoulder pain, without numbness and tingling. Pain is usually the first symptom of disc degeneration, beginning intermittently upon strain, and progressively becoming more persistent and finally resulting in chronic neck pain. Muscle weakness and loss of dexterity suggests more serious cervical disc degeneration, and in severe cases there may be evidence of spinal cord compression causing sciatica and back pain with difficulty walking and lower extremity dysfunction.
Diagnosis of Degenerative Disc Disease in the Neck
A thorough case history and physical exam forms the basis of an initial investigation into degenerative disc disease in the neck. The physician will ask about previous trauma to the neck and back and most likely measure neck extension, flexibility, and tenderness on palpation. Testing the resistance (and the presence of pain) in the arms and head when performing certain movements can highlight specific areas to investigate more thoroughly. Weakness of grip in one hand or both may indicate disc herniation or severe degeneration. Patients may be asked to mark on a diagram where they are experiencing pain, numbness, tingling and other sensory problems.
Where warranted, the physician may order x-ray, MRI, or CT scans to confirm the location and severity of cervical disc degeneration. These scans will also highlight the presence of confounding phenomenon such as calcification of ligaments, cervical arthritis (spondylosis), and cervical spinal stenosis. Osteophyte growth will also be looked for in these scans as these bone spurs may be impacting on the disc and facet joints causing further degeneration. Osteophyte growth, disc bulging and herniation, ligament inflammation and calcification all serve to reduce the foramina through which the spinal nerves travel, leading to pinched nerves. MRI scans are particularly effective at revealing the presence of disc herniation and spinal nerve compression. Myelograms, where contrast fluid is injected into the cerebrospinal fluid spaces and followed by an x-ray, can be useful in revealing compression on nerve roots, but have largely been replaced by the less invasive MRI scans. CT scans can evaluate the skeletal structure of the cervical spine showing stenosis and nerve root impingement. Electromyograms and nerve conduction studies can pinpoint the affected nerves, with significant ramifications for the treatment of degenerative disc disease in the neck.
Treatment of Degenerative Disc Disease in the Neck
Conservative treatment is usually the first course of action recommended by a physician for cervical disc degeneration. For those with neck pain, but no evidence of nerve root compression or muscle weakness, the use of NSAIDs and analgesics, along with physical therapy, is common practice. Muscle relaxants may also be prescribed and ice packs can reduce the swelling and inflammation in the neck. Alternative anti-inflammatories and natural pain relief supplements offer another therapeutic course for those concerned with the side-effects of pharmaceutical medication. Spinal manipulation through chiropractic or osteopathic treatment may be helpful in some cases but should be approached with caution as these types of therapy may serve only to exacerbate an existing underlying condition such as cervical spinal stenosis. A good practitioner will want to take a thorough medical history prior to conducting any treatment and may themselves advise against treatment in some cases. Always make sure the practitioner is accredited by the appropriate governing body.
Cervical Collars, Neck Exercises and Pain Relief Devices
Soft cervical collars may be used briefly in order to give the neck muscles a rest. Longer-term use of the collars is likely to lead to muscle atrophy however, and is, therefore, not recommended. Cervical collars may be used for two days or so to allow rest, but should then be followed by mobilization, gentle, supervised, stretching and strengthening exercises for the neck. Cervical traction may grant some relief from symptoms for some patients and may be achieved at home using neck pain pillows, and devices for neck pain relief. Discussing these therapies with the consulting physician is wise so as to avoid the potential for exacerbating a condition however.
Epidural Steroid Injections
For those who are suffering from muscle weakness and pain from nerve root or spinal cord decompression surgery may be offered as an early option. Muscle weakness demonstrates that the nerves are being injured, making the relief of the pressure on the nerves an urgent priority. Epidural steroid injections are not usually used in the cervical neck as this procedure is more complex than for the lower (lumbar) spine due to the tight spaces involved in the neck structures and the risk of injury to the area. Cervical epidural steroid injections may be used in cases where arm pain and weakness occur through radiculopathy, although outcome is variable and effectiveness has not been demonstrated in the literature.
Degenerative Disc Disease Surgery
If degenerative disc disease does not respond adequately to conservative treatment and there is evidence of associated myelopathy, motor weakness, progressive neurological defects, and evidence of spinal cord compression surgery is the likely course of action. Even if conservative treatment has not alleviated the condition to a manageable degree within six months, surgery is still contraindicated if the attending physicians cannot accurately pinpoint the cervical spinal space that is the site of the problem.
Where discs have herniated, decompression of the spinal cord will be performed, and may be accompanied by a discectomy, or an anterior cervical discectomy and fusion (ACDF). An ACDF is a procedure to remove the affected disc and fuse the associated vertebrae in order to stabilize the spine in that area. Usually just one disc is operated on in this procedure, although surgeons may remove two discs on some occasions and fuse a larger portion of the spine together if warranted. Anterior discectomy (where the surgeon approaches from the front of the neck) is usual, but posterior cervical disc surgery may be preferential in some cases. Total disc arthroplasty presents another surgical option for one or two-level cervical disc removal; it shares the same risk as ACDF for adjacent segment disease (Jawahar, 2010). Laminectomy is another possible procedure which removes an area of bone in the back of the spine in order to enlarge the space in the spinal canal and reduce compression on its structures.
Post surgery the patient should be thoroughly monitored for neurological function. Analgesics and anti-inflammatories are frequently prescribed and, depending on the procedure the patient may be up and ambulatory within a day or two. Some procedures have a longer recovery time, such as the laminectomy which can take months to recover from fully. The resumption of light activities should be discussed with the physician, and any alterations in the condition reported immediately. Scans such as radiographs and further x-rays will be performed to establish the fusion of any bone grafts or plates inserted during the surgery.
Degenerative Disc Section References
Jawahar, A., Cavanaugh, D.A., Kerr, E.J., 3rd, Birdsong, E.M., Nunley, P.D., (2010), Total disc arthroplasty does not affect the incidence of adjacent segment degeneration in cervical spine: results of 93 patients in three prospective randomized clinical trials, Spine J. 2010 Sep 22. http://dx.doi.org/10.1016/j.spinee.2010.08.014
Jeng, C.M., Cheng, T.C., Kung, C.H., Hsu, H.C., (2010), Yoga and disc degenerative disease in cervical and lumbar spine: an MR imaging-based case control study, Eur Spine J. 2010 Aug 15. PMID: 20711844
Windsor, R.E, Nieves, R.A., Sullivan, K.P., Hiester, E.D., (2004), Cervical Discogenic Pain Syndrome, eMedicine, Eds. Janos P. Ertl, et al. 30 Sep. 2004. Medscape. 19 Nov. 2004, http://emedicine.com/sports/topic19.htm