Cervical Stenosis

Understanding Cervical Spinal Stenosis

Cervical spinal stenosis (related to the spine in the neck) is the narrowing of a canal or vessel. It causes constriction and compression (pressure) on the spinal cord.

The spinal cord carries all information from the brain to the body, and from the body back to the brain. When there is pressure on the cord, this can result in a reduced flow of information back and forth.

How Do I Know If I Have Cervical Spinal Stenosis?

Cervical spinal stenosis can have several causes.
  • Congenital spinal stenosis: Stenosis can be congenital, meaning a patient is born with a smaller-than-average canal (just like some people have larger feet or ears).
  • Consequences of arthritis: The inflammation and changes in joint structures associated with arthritis can contribute to the narrowing of the spinal canal, potentially causing symptoms of spinal stenosis.
  • Degenerative spinal stenosis: The normal aging process can result in ridging of the spinal canal at the disc spaces, as well as gaps in between.
  • Trauma: Trauma can speed up the normal degenerative process. It can also cause normal tissue to be displaced into the spinal canal through a herniation of the disc material, fracture of the bones in the canal, or of contents of the facet joints (synovial cysts).
  • Tumors: Cancerous or benign, tumors can cause spinal stenosis by growing from within the spinal cord, or from one of the nerve roots that arise from the spinal cord. They may cover the spinal cord. In some cases, tumors have spread to one of these structures from another place in the body (also known as spinal metastasis).
  • Infections: Infections that occur in or around the spine can cause spinal stenosis, often with rapidly progressing and devastating effects.
  • Multiple conditions: More than one of these conditions can occur at one time, resulting in cervical spinal stenosis. For example, someone living with a congenitally small canal can develop mild to moderate arthritis or a disc herniation that otherwise might not be large enough to be symptomatic. When two conditions are combined, the result can be even more severe.

Symptoms of Cervical Spinal Stenosis Include:

  • Weakness in the hands, arms, legs, or trunk muscles
  • Impairment of the bladder or bowel function. This can include incontinence such as the inability to stop going, experiencing accidents, or retention where it’s hard to get rid of contents. Patients may feel constipated or like they “can’t go.”
  • Difficulty controlling your arms, legs, or body. This includes uncontrollable spasms, lack of coordination when walking, or loss of control in the hands.
  • Pain in the body. This includes sharp, burning, or electrical pain which can travel up or down the neck, back, arms, or legs.

How is Cervical Spinal Stenosis Treated?

Cervical spinal stenosis can have several causes.
  • Associated deformity.
  • The root cause of the stenosis.
Cervical spinal stenosis can be treated with anterior procedures like discectomies or corpectomies. They can also be treated with posterior procedures in the neck including a laminectomy with or without fusion, laminoplasty, or minimally invasive treatments when appropriate.

Simple Cervical Discectomy

An anterior cervical discectomy is one of the oldest procedures performed by spinal surgeons, though it has fallen out of favor due to several potential consequences:
  • Chronic neck pain: Without the benefit of a disc to separate them, vertical vertebral bones can rub against each other, causing chronic pain.
  • Additional strain: Once the disc is removed, it collapses and the neck becomes more kyphotic, which can put more strain on adjacent levels in the spine.
  • Pinched nerves: When the disc is removed, the space between the bodies becomes smaller which results in a greater likelihood of pinching the nerves where they leave the spine.
Although most spine surgeons still perform this procedure, many favor performing a discectomy and either a fusion or an artificial disc replacement where appropriate. Occasionally, there is a reason for performing a simple discectomy without accompanying treatment.

Cervical Discectomy with Fusion

In the 1950s, Cloward, Smith, and Robinson popularized different techniques of placing a bone graft where the disc used to be to prevent consequences. In theory, by keeping the alignment in the neutral lordosis, there should be less degeneration in adjacent levels over time. By keeping the two vertebral bodies apart, there should be less pinching of nerves over time.

Encouraging bones to fuse typically results in reduced neck pain as the two vertical vertebral bones no longer rub against each other without the benefit of a disc between them. The distraction of the two bodies kept the ligaments in the spinal canal from bulging into the canal and spinal cord preventing delayed spinal stenosis. At this time most surgeons who perform a discectomy with a fusion will do so using a plate on the front of the spine to help the fusion along. This is called instrumentation.

Discectomy with Total Disc Replacement (TDR)

Instead of replacing the disc material with a bone graft, some surgeons choose to replace the disc with an artificial disc implant that normally allows for some movement at the level operated on, instead of fusing and eliminating movement at that level. This is typically only performed for a limited number of patients who are deemed ideal candidates for the procedure. The theoretical advantage is that it preserves some motion at that level, even if it is not completely normal motion. This approach has the same advantages fusion has over simple discectomy, in that it prevents collapse and kyphosis, and most of the consequences listed above.

The FDA-approved indications for cervical TDR are for single-level disease without significant facet disease and are primarily indicated for disc herniation with nerve root compression. Any use other than above is considered “off-label”, including more than one level of disc implantation. Some patients do go on to fuse around the artificial disc. Outcomes after both an artificial disc replacement and after discectomy and fusion are generally good, with a return to function. One exception is that professional athletes such as NFL players and combat pilots in the military are not usually cleared to return to active duty or play after an artificial disc replacement. There is generally a much longer follow-up experience following a fusion than there is after a disc replacement. A newer generation of disc replacement will likely come along, and additional information about the long-term results in such high-performance athletes may change these recommendations.

Anterior Keyhole Cervical Foraminotomy

For those patients whose spinal stenosis is caused by a single off-centered disc herniation or bone spur from the disc space (anterior osteophyte), a small procedure with a similar approach as the discectomy can remove the compression without complete removal of the disc, and without a fusion. This procedure involves less disruption of the rest of the disc space. With the majority of the native disc material left untouched, the patient can maintain their pre-operative range of motion. The restrictions are slightly less after an anterior foraminotomy for discectomy or decompression. Consequently, recovery is slightly easier.

However, this procedure does have a significant recurrence rate (precisely because it does not involve the removal of the entire disc material, which typically requires a fusion or total disc replacement.), This does result in some damage to the disc. Although most surgeons who perform this procedure will not completely immobilize the patient after surgery in a collar, strenuous activity is typically curtailed initially.

Cervical Corpectomy

A more complete removal of the vertebral body is required if:
  • Compression is more than just disc material or bone spurs at the disc level.
  • A major deformity is involved.
  • Removal of the entire vertebral body is necessary because of a tumor of another disease involving the bone.
This is called a vertebrectomy or a corpectomy. Whenever a corpectomy is performed, either a fusion or instrumentation is usually performed. This is to maintain a more ideal position. The corpectomy is more destructive than a discectomy and fusion and may have a higher non-union rate. Multilevel procedures are more likely to require a second procedure to provide supplemental instrumentation from the posterior approach to ensure a solid fusion.

Posterior Cervical Procedures

Cervical Laminectomy

Laminectomy has been performed for more than 80 years by taking the back of the spinal canal off, like opening a convertible roof or a can of sardines. By removing the back of the canal (an “ectomy,” or removal of the lamina or back of the spine), the contents of the spinal canal (the spinal sac, with its column of spinal fluid and the spinal cord and nerve roots) can expand backward and be less compressed. This usually alleviates or improves the neurological symptoms caused by compression and gives the best environment for recovery.

However, there are many circumstances where the removal of the bone in the back results in delayed kyphosis or forward tipping. This forward tipping essentially bends and stretches the spinal cord over the disc spaces and bone spurs, and over time this can result in more neurological symptoms. For this reason, most spine surgeons will perform instrumentation and fusion with a laminectomy when done for spinal canal stenosis especially if there is already forward or kyphotic tipping of the spine, or if there is a significant weakness to suggest that the muscles will be too weak to hold the neck in position over time.

Cervical Laminectomy with Fusion

Fusion, when performed as part of a laminectomy, will eliminate movement in the levels fused. This is usually achieved with some form of instrumentation to hold the bones rigidly until they heal while adding stability to the neck (assuming the fusion heals properly). Most skilled practitioners believe that getting the spinal alignment to fuse in as close to the normal neutral lordosis will keep the remaining levels from degenerating as quickly. There are various competing forces and issues involved, such as difficulty in getting the alignment of the spine corrected, risks of being more aggressive, and others. Where possible, we try to restore or maintain a 20-degree or more curve within the entire cervical spine (normal is generally considered 20 to 40 degrees.)

The consequences of the procedures include:

  • Reduced range of motion in the neck. (The amount of motion affected depends on the levels fused.)
  • Slightly increased risks associated with the more extensive nature of placing screws, cables, or other forms of instrumentation into the spine.
  • A need to observe the patient for a year or so following the operation to make sure the fusion takes and/or to monitor for the development of pseudoarthrosis (failed fusion – see revision spinal surgery ).

Cervical Laminotomy or Cervical Foraminotomy

When the area of stenosis is less extensive or off to one side, a smaller procedure can be performed. Some disc herniations can also be treated by a small procedure from the back of the neck, which doesn’t require a fusion to achieve decompression of the nerves or spinal cord. The indications for a “keyhole” foraminotomy [because the surgery is small like an old-fashioned keyhole] may be different from that of a discectomy or laminectomy. In some cases, either procedure may be appropriate.

Cervical Laminoplasty

A cervical laminoplasty is used to repair (“-plasty”) or treat the lamina when there is significant spinal stenosis. This procedure is a “motion-sparing” procedure having the advantage of maintaining most of the range of motion a patient had pre-operatively (as opposed to a fusion) but still significantly increasing the canal area (almost doubling the space available for the cord). The procedure allows for the retention of the majority of the normal anatomy of the spine, which keeps the spine from tipping forward over time. While there are several techniques for performing a laminoplasty of the cervical spine, Dr. Jenkins typically employs the “open door” technique.

Essentially, the back of the spine (lamina) is hinged open on one side after cutting it free and elevating it from the other side. It is usually held in place by a custom titanium miniplate designed just for this procedure. It’s like raising the roof on one side of the house, but because the roof is curved or with a reverse “V” shape, once elevated, it takes on a shape like the top of an octagon.

This procedure should not be applied to patients whose spines are already severely tipped forward (Kyphotic) or to those where instability is present.

This procedure can be performed either as a laminoplasty at all levels (Case 1). When part of the region to be operated on is already somewhat unstable and requires instrumentation and fusion, a hybrid procedure can be performed in the part that is not unstable (Case 2).

Case Study 1: Laminoplasty for acute spinal cord injury

A 14-year-old boy who was checked to the ground playing basketball started with hand and leg weakness and progressed to near quadriplegia (almost no function in arms or legs).

Case Study 2: Hybrid laminectomy with fusion, and laminoplasty

A 51-year-old musician with progressive hand weakness and incoordination. He was noted to have severe degenerative changes from C5 to T1, but also to have superimposed congenital stenosis which made the condition worse.
Instead of fusing 5 levels, we only fused 3 levels and left the other two levels decompressed via the laminoplasty procedure. The patient was very satisfied with the range of motion he had post-op.

AVAILABLE TREATMENTS

ANTERIOR KEYHOLE CERVICAL FORAMINOTOMY
LAMINECTOMY WITH FUSION
CORPECTOMY
LAMINOTOMY
DISCECTOMY