What is a Cervical Disc Herniation?

When one of the intervertebral discs is exposed to either mechanical forces, or inflammatory mediators that alter disc integrity, it can bulge out and impact surrounding structures such as nerves (this is called a disc herniation). Typically, these disc herniations will occur on the posterior (back) side of the vertebral column because the annulus fibrosis is thinner on the posterior side and lacks some of the structural support seen on the anterior (front) side.

Cervical disc herniations can be divided into acute or chronic herniations. In acute herniations, a traumatic event (such as a motor vehicle accident or high impact sport collision) leads to damage of the annulus fibrosus. The pressure and forces of the collision or trauma causes the nucleus pulposus to bulges through the damaged fibers, resulting in a hernia. As these hernias have a sudden and direct mechanism of injury, symptom onset is usually sudden and severe.

In contrast to acute cervical disc herniations, chronic cervical disc herniations make up most hernias, and these have a more gradual onset. Disc degeneration as a result of aging can commonly lead to cervical disc herniation. As the intervertebral discs degenerate and age, they are no longer able to support the forces that are applied to through them, and the nucleus pulposus herniates out of the weakened or damaged annulus fibrosus, which can in turn lead to an impinged nerve root.

Anatomy of the Cervical Vertebra:

In the cervical spine, there are intervertebral discs in between each of the vertebral bodies that acts as a shock absorber. The intervertebral discs have something called the nucleus pulposus at their center which is essentially extracellular matrix that forms a gel-like substance between the vertebrae. This gel like substance is contained by the lamellar annulus fibrosis, which as its name indicates is a series concentric rings that have a sturdier fibrous composition.

Risk Factors:

Risk factors for cervical disc herniations include older age, lack of regular exercise, tobacco use, injury, occupation, poor posture during standing and sitting, poor body mechanics when carrying out activities requiring lifting or rotation, and inadequate nutrition. Most of these factors are modifiable, meaning that there are many things that can be avoided in order to mitigate the risk of developing a cervical disk herniation.

Signs and Symptoms:

Cervical disc herniation is a common source of cervical radiculopathy which may lead to sensory deficits, motor weakness, and/or radicular pain. The specific signs and symptoms of cervical vary based on which vertebral level is affected. This is because depending on where the herniation occurs, it will lead to compression of a different spinal nerve. The symptoms of cervical disc herniations are unique to each spinal nerve as each one innervates different muscles and areas of the body.

Cervical disc herniations occurring at C6-C7 are the most common. These herniations will affect the C7 nerve root. Symptoms of CDH with radiculopathy involving the C7 spinal nerve include pain and/or numbness across the back of the shoulder, triceps, the back and side of the forearm, and the back of the middle finger. The main motor deficit seen with a C6-C7 cervical disc herniation is triceps weakness, but it may also involve wrist flexors and finger extensor weakness. Additionally, the triceps reflex is often diminished or absent.

The second most common cervical disc herniation is of the C5-C6 disc which affects the C6 nerve. Symptoms of cervical disc herniation involving the C6 spinal nerve include pain and/or numbness radiating from the neck to lateral biceps, lateral forearm, and tips of digits 1 and 2, motor deficits of the wrist extensors and biceps, and the brachioradialis and biceps reflex is decreased or absent.

The third most common cervical disc herniation is of the C7-T1 disc which affects the C8 nerve. Symptoms of CDH with radiculopathy involving the C8 spinal nerve include numbness in the medial arm, medial forearm, medial hand, digits 4 and 5, motor deficits of the flexors and extensors of the wrist and fingers such as flexor digitorum profundus and flexor pollicis longus, pronator quadratus, and intrinsic hand muscles including lumbricals 3&4.

Most symptomatic cervical disc herniations occur in individual age 40 and older. The reported ratio for male to female incidence varies from 1:1 to 1.4:1. As you can see, herniations in the cervical spine can have a huge effect on sensory and motor function of the upper arms, forearms, hands, and fingers which would have a great impact for any athlete. Luckily, cervical disc herniations are often treated very successfully through conservative measures such as physiotherapy.

Treatment and Management:

Conservative management of cervical disc herniations include:

• brief periods of immobilization

• range of motion exercises

• strengthening exercises

• modalities such as electrical stimulation and ultrasound

• some patients may benefit from cervical manipulation as a means of short-term pain relief and relief from cervicogenic headaches

For patients who do not respond well to conservative treatment strategies, more invasive strategies are considered.

• Some patients receive benefit from spinal steroid injections. These injections require a pathological confirmation via MRI before being administered but can effectively remove symptoms through selective nerve blocks.

• surgery should be considered when pain persists for 6-12 weeks after conservative treatment or when there is evidence of progression or a functionally important motor deficit

Cervical disc herniations are shown to have favourable outcomes with few cases of long-term disability being reported amongst cases. Most patients initially present with intense pain and moderate to severe levels of disability. Substantial improvements in pain and disability for symptomatic disc herniation often occurs within the first 4-6 months after symptom onset and this is the case for both acute and chronic cases. These improvements are generally maintained long term, however, recurrences in pain are not uncommon and can occur at 24-36 months post injury but are typically at a lower severity than the initial onset of symptoms. Physiotherapy is the most common form of conservative management for cervical disc herniation and is useful and effective at every stage along the recovery continuum.

To learn more about cervical disc herniation and treatment options, visit our Main Street physiotherapy clinic in Vancouver.

Original Article by Rachel Rubin-Sarganis

Photo by Kyle Mills