Tuesday, January 24, 2012

Herniated Disc Cervical Spine

A herniated disc cervical spine is a common condition that can lead to a considerable amount of neck, shoulder, arm and hand pain.
Injury
To understand the cervical spine is to understand the anatomy of the cervical spine. Discs, which are sandwiched between the vertebrae, act as the spine’s protective shock absorbers. In essence, they are like a jelly-filled donut that contains the annulus (the outside of the donut) that surrounds the nucleus pulposus (the gel-like substance within the donut). The annulus is made up of about 30 layers that act just like the plies of a tire. If some of these plies break or tear, just like taking a cap off a toothpaste tube and squeezing the tube, the gel-like substance inside can squeeze out. This extrusion of jelly is the actual herniated disc.
This herniated disc material can ultimately put pressure on nerve roots which live right next to the disc and occasionally on the spinal cord itself.  In addition, the substance that makes up this gel (the nucleus) also contains substances that are toxic to nerves. Why God or Mother Nature designed the disc this way is anybody’s guess. This toxic substance can cause inflammation within the nerve, which can lead to arm pain even without direct compression of the nerve itself.
If the herniated disc cervical spine compresses a nerve root, nerve pain will normally develop down the arm into the shoulder or to the hand (depending upon the nerve root involved).  This is called radiculopathy. If the herniation compresses the spinal cord it is called myelopathy and information on this condition is found in another section on this web site.
Symptoms
Depending upon the position of the disc herniation, it may cause pain in the neck, shoulder, arm or hand. Common symptoms are pain and numbness or occasionally just weakness of the muscles of the nerve that is compressed. Depending on the nerve, pain may radiate only into the shoulder or may radiate down the arm into the fingers. Almost all cervical spine herniations radiate pain into the shoulder blade on the side of the herniation.
There are many patients that have pain that radiates only to the area between the shoulders and these symptoms are commonly misdiagnosed as thoracic or scapular (shoulder blade) pain when the pain is really referral pain from the compressed nerve in the neck.
If present muscle weakness may not be revealed unless the individual lifts weights and is familiar with which muscles are used with different positions. Sometimes, the weakness is significant and disabling. Other times, just feeling clumsy and dropping objects can be a symptom of weakness.
Biomechanics
The biomechanics of this disorder are easy to understand. The nerve hole itself becomes larger with bending the head forward and away from the side that it is on. Bending the head backwards or to the side that the nerve hole or foramen is on will narrow the hole. Therefore, with a herniated disc, arm and shoulder pain will normally become worse with bending backwards or to the side of the arm pain as this maneuver causes further compression to the nerve. Obviously avoid any head motions that increase the pain into the arm, as it is not a good idea to crush this nerve any further.
Most of the varying herniations will cause moderate discomfort to intense pain in the shoulder, neck and upper back area depending on the location of the herniation.  The most common symptoms are a dull, nagging pain in the neck or between the shoulder blades. This pain will become more intense if the patient bends the neck backwards (this narrows the hole the nerve lives in) or with lifting or exercising.  Some activities can be more painful (bike riding with a low stem and swimming can extend the neck causing increased pain).
Treatment
Non-Surgical
Medications, injection therapies, physical therapy and rest can relieve the symptoms of a herniated disc cervical spine.  If the symptoms persist or the weakness is significant, then surgery may be recommended.
Surgical
The most common surgery performed to treat a herniated disc in the cervical spine is an ACDF (Anterior Cervical Decompression and Fusion). With this surgery, the offending torn disc is removed, the nerve root pressure can be relieved and the segment stabilized with a fusion.  This procedure can be performed microscopically which will use a smaller incision and leads to a faster recovery.  There are times that the fragment can be removed posteriorly in a procedure called a posterior cervical foramenotomy.  (See surgical section for information on both procedures.)
An artificial disc can be implanted to allow motion to continue after surgery. There are risks and benefits of this procedure.  (See the section on cervical artificial disc surgery.)

This is a side view (sagittal) MRI of a large disc herniation in the cervical spine (neck). The arrow points to the herniation

This is an MRI of a cervical herniated disc. The arrow points to the extruded fragment that is pushing the spinal cord to the opposite side of the canal and the nerve root that exits here is under significant compression.

This is a side view picture of a patient who had significant compression of his C5 nerve for a period of time. You can see the “hollowing out” of the back of his shoulder where the deltoid muscle has undergone significant atrophy.

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