A cervical herniated disc occurs when part of the normal spinal disc between any two of the neck vertebrae has been pushed out of its normal position and into the space of the spinal canal where the spinal cord or nerve roots become vulnerable to injury from the protruding disc. The outer fibrous ring (annulus ) of the disc is torn with the inner nucleus pulposus s spilling into the canal and nerve root area (view herniated disc pushing back on the spinal cord, see Figure 1 & 2 ). Single nerve root involvement (monoradiculopathy ) is more likely to occur with disc herniation than multiple root involvement (polyradiculopathy ), however, both can affect pain in the neck, shoulder, or arm.
There are several types of cervical disc herniations in that they can be classified as soft or hard. A ñsoftî herniation is generally more acute, where a portion of the inner core of the disc (nucleus pulposus ) herniates, or ruptures through the outer protective fibers (annulus ). The disc space at which this occurs may have little to no arthritic or degenerative changes. A hard disc herniation usually describes a more chronic condition where secondary degenerative changes (spondylosis ) such as partial calcification of the disc herniation have occurred. Nonetheless, both of these types may cause neural compression, or ñpinching of the nerve,î and produce similar signs and symptoms affecting pain in the neck, shoulder, and arm.
Disc herniations most commonly occur toward the sides of the spinal canal, where the nerve roots are located. Their protrusion, therefore, most commonly causes symptoms of nerve root irritation and/or damage (radiculopathy ), including pain radiating into the arm. Only a single nerve root (monoradiculopathy ) is involved in most cases. Symptoms can include neck, shoulder, and arm pain, paresthesias  (tingling or burning sensation), and numbness. Weakness of one or more muscles normally being controlled by the affected nerve can occur, with complaints of loss of strength, and trouble lifting the arm, bending the elbow, or holding onto objects. Most cervical disc herniations occur in the mid to lower part of the neck, the C4-5, C5-6, and C6-7 interspaces, and affect the nerves running all the way to the hand.
Cervical myelopathy, or dysfunction of the spinal cord, can occur due to pressure of a herniated disc directed straight back against the spinal cord. It is characterized by weakness and clumsiness of the upper and/or lower extremities, changes in walking pattern, sensory changes, and rarely loss of control of bowel and bladder function.
The diagnosis of cervical herniated disc and the conditions it causes is largely based on the medical history and physical examination. Plain X-rays will likely be the initial imaging tests which are done mainly to rule out other abnormalities, as the discs are seen only as spaces on X-rays and the herniation cannot be visualized. Myelography with CT scan may be used to further define any changes in anatomy. MRI scanning is the next test most often done, due to its superior resolution of soft tissues and excellent visualization of the disc and nerve elements.
Treatment for most cases of suspected or documented cervical herniated discs may include: a temporary period of brace immobilization, therapeutic exercises, and medication, including nonsteroidal anti-inflammatory pain medicines (NSAIDs ) such as ibuprofen or aspirin, muscle relaxants, and occasionally stronger pain killers.
Organized physical therapy for cervical herniated discs often includes isometric neck strengthening exercises as well as traction therapy which can also be performed at home. The vast majority (90%) of patients will respond to these modalities within 3 months and need no further treatment. Indications for surgery include myelopathy with progressive motor/gait impairment due to spinal cord dysfunction, or radiculopathy with persistent disabling pain and weakness lasting more than 6 weeks. Occasionally, surgery is warranted with less than 6 weeks of symptoms due to uncontrollable severe pain or progressive neurologic problems. Surgery most commonly entails removing the disc herniation from the front of the neck along with a fusion of the vertebrae surrounding the disc to ensure vertebral column stability. Less commonly, removal of the herniation from the back of the spine can be done, decompressing the spinal nerve without the need for spinal fusion.
The prognosis for recovery following a cervical herniated disc is good, with most cases responding to nonoperative treatment and surgery - resulting in 90 percent success rate.