To understand cervical spine surgery, it is important to know about neck anatomy, spinal conditions that can affect the cervical spine, and surgical goals and techniques used to address neck pain. This article will review that information, and it begins with a quick cervical spine anatomy lesson. It's important to know how your neck is supposed to fucntion in order to better understand why you have pain, as well as what will be done to address your condition in surgery.
The cervical spine contains 7 bones, called the cervical vertebrae. These bones are stacked on top of one another and linked by discs, ligaments, and muscles.
The vertebrae are numbered C1 through C7. The first vertebra, C1, is also called the atlas because it joins with the base of the skull and supports the head (just as Atlas supported the weight of the world in Greek mythology). C2, the second vertebra, is called the axis because the head and C1 swivel around it. These two vertebrae enable most neck movement.
The vertebrae below C2 are only referred to by number; however, all of them have the same basic structure including:
Spinal Cord and Nerves
The spinal cord runs through the cervical spine. It is protected in front by the vertebral bodies and behind by the lamina. Nerves that control arm function branch off from the spinal cord in the cervical spine.
The nerves exit the cervical spine through small holes called foramina.
Starting at C2-C3, an intervertebral disc sits between each vertebra. Intervertebral discs are pillow-like structures, with a tough outer ring (the annulus fibrosus) and a dense, jelly-like center (nucleus pulposus).
Intervertebral discs perform 2 important functions:
Although the discs are tough structures, they are susceptible to damage. The wear and tear of normal living can cause the disc to degenerate and lead to osteoarthritis (spondylosis) of the vertebra. This is similar to the arthritis that affects hip and knee joints.
Degeneration in the cervical spine can lead to significant changes in anatomy. These changes can cause neck pain and other symptoms due to:
Cervical degeneration includes distinct characteristics, some or all of which may be present in a neck pain patient.
The lumbar spine is illustrated above, along with disc problems.
Characteristic 1: Bulging Disc (or Even a Herniated Disc)
As a disc deteriorates, it may begin to bulge, or even rupture. If it ruptures, its jelly-like middle (nucleus pulposus) may protrude. A bulge may protrude backward and press against the spinal cord or cervical nerves. Rarely, pressure on the spinal cord may cause a patient to lose hand dexterity, bowel or bladder control, and/or experience difficulty walking (myelopathy). This type of myelopathy is serious and requires immediate medical attention.
Sometimes, the degenerated disc protrudes into one of the holes (foramina) where the nerve exits from the spinal column. In this case, symptoms may occur only in the arm on the side where the disc protrusion touches the exiting nerve. Since the nerves provide arm function, the individual feels pain, numbness, tingling, or burning in the arms even though the actual problem is located in the neck. This is called radiculopathy.
Characteristic 2: Loss of Disc Height
As a disc degenerates, it loses it shock absorption capability and may cause neck pain since the joints can no longer move as effectively or safely.
Characteristic 3: Bone Spurs
As degeneration continues, the bones may begin to develop "spurs" which are called osteophytes. Osteophytes can protrude into the spinal canal or foramina, causing spinal cord or nerve compression. This may cause neck pain, arm symptoms (radiculopathy), or spinal cord dysfunction (myelopathy).
Characteristic 4: Facet Degeneration
The cartilage surfaces on the facet joint may erode away, causing facet pain.
If cervical degeneration causes myelopathy (spinal cord dysfunction), radiculopathy (dysfunction of nerves to the neck or arms), neck pain, or abnormal neck motion, surgery may be necessary. The surgical goal is to reduce pain and restore spinal stability.
Surgeons use 2 overall surgical techniques to address neck pain:
These 2 techniques may be used in combination, or you may just have a decompression surgery or just a stabilization surgery.
Understanding Decompression Surgery
Decompression procedures can be done from the front (anterior) or back (posterior) of the spine, depending on how and where the nerve tissue is being compressed.
In decompression, the tissue pressing against the nerve or spinal cord is surgically removed, or more space is created for the nerve tissue to remain unobstructed. The main types of surgical decompressions are:
Foraminotomy: If intervertebral disc material or a bone spur is pressing on a nerve as it exits through the foramen, a foraminotomy may be done. Otomy is the medical term for making an opening. Therefore, a foraminotomy is making the opening of the foramen larger, so the nerve can exit without being compressed.
Laminotomy: Similar to foraminotomy (see above) but involves making a hole in the lamina to create more space for the spinal cord.
Laminectomy: Ectomy is the medical term meaning removal of. A laminectomy removes part or all the lamina to reduce pressure on the spinal cord.
Facetectomy: Involves removal of the facet joint to reduce pressure on the exiting nerve root.
Laminoplasty: Plasty means to shape an anatomical structure to restore form or function. In this case, laminoplasty refers shaping the lamina surgically to create more room for the spinal cord.
Each of the decompression techniques above are performed from the back (posterior) of the spine. However, sometimes a surgeon must perform a decompression from the front (anterior) of the spine. For example, if a disc bulges into the spinal canal, it sometimes cannot be removed from behind because the spinal cord is in the way. Therefore, the decompression is usually performed from the front (anterior) of the neck.
Types of anterior decompression techniques are:
Discectomy: Surgical removal of all or part of the herniated disc.
Corpectomy: Occasionally disc material becomes lodged between the vertebral body and the spinal cord, and cannot be removed by a discectomy alone. In other cases, bone spurs form between the vertebral body and spinal cord. In these situations, the entire vertebral body may need to be removed to gain access to the disc material. This procedure is called a corpectomy (corpus means body and ectomy refers to removal).
TransCorporeal MicroDecompression (TCMD): TCMD is a minimally invasive procedure that accesses the cervical spine from the front of the neck (anterior). The procedure is performed through a small channel made in the vertebral body to access and decompress the spinal cord and nerve. TCMD can be performed as a stand-alone procedure or with Anterior Cervical Discectomy and Fusion (ACDF) and/or total disc replacement.
Understanding Spinal Stabilization
Discectomies and corpectomies usually result in an unstable spine. Instability denotes abnormal motion in the spinal column, raising the potential for serious neurological injury. In these situations, the spine is often surgically restabilized. The main restabilization surgical techniques are:
Fusion: Fusion is the bonding together of bones, usually with the aid of bone graft or a biological substance. A fusion stops motion between 2 vertebrae and provides long-term stabilization. It is very similar to natural fracture healing.
In a cervical fusion, adjacent vertebral bodies, facets, and/or the lamina may be fused together.
If the fusion is done from behind (posterior), the surgeon typically will lay strips of bone graft from one lamina, or lateral (side) mass to the lamina, or lateral mass below. Usually, bone graft will fuse across these structures over time and stabilize the two vertebrae. The surgeon may use a similar technique to fuse the facet joints together, too.
Instrumentation: Posterior cervical fusions can be supplemented by specially designed fixation devices such as wires, cables, screws, rods, and plates. These devices increase stability and facilitate fusion.
Understanding Decompression and Fusion
Sometimes, a surgeon will perform both a decompression and a fusion. For example, after a discectomy, a gap will exist between the vertebral bodies. This gap is typically filled with a bone graft (from the patient's pelvis or from a bone bank), or spacer that supports the spine and promotes fusion. This type of procedure is called an anterior cervical discectomy and fusion or ACDF.
Today, many surgeons apply fixation devices (plates with screws) to the anterior spine when performing an ACDF or cervical corpectomy. These devices help to promote stability while the fusion heals.
Artificial Discs: Another Surgical Option
Recently, many spine surgeons are using a new technology in their cervical spine surgery. Instead of fusing the spine after a discectomy, surgeons are implanting an artificial cervical disc. The advantage is that an artificial disc enables a patient to retain normal neck movement after surgery. Previously, if the patient had 2 or more vertebrae fused, neck motion would be greatly reduced.
Conclusion: Cervical Spine Surgery May Be an Option for You
If your surgeon recommends cervical surgery, you can be encouraged that cervical decompression and stabilization procedures are some of the most successful operations spine surgeons perform today. Patients generally have rapid recovery and quickly return to activities of daily living with complete resolution of their neck pain and other symptoms.