Spinal Stenosis in the Elderly
It is commonly said that there are two certainties in life: taxes and death. Well, I want to suggest that there is a third; arthritis. The common type of arthritis, osteoarthritis, is not really a disease but simply the wear and tear of living on the joints. I often tell my patients to think of arthritis like rust on a hinge: it develops over time, it makes the surfaces irregular resulting in squeaking and stiffness, and if the hinge is not used it will get stuck. Another point I make is that a “joint” is where two bones meet and move, such as elbows and knees, but also including the various bones or vertebrae that make up the spine. Actually there are three joints between each two vertebrae, and twenty-five of these joint “levels” from the head to the sacrum. So there are many joints in the spine, each of which will wear down with use. No wonder almost everyone will develop some arthritic trouble in their back over time.
The most common spine problem of age is simply the stiffness and occasional discomfort due to arthritis. A common example is the trouble you have getting out of bed in the morning and feeling the need to “stretch” your back: this is arthritis in action. The longer you live, the stiffer and slower you will be in the morning. Granted that people start having arthritis symptoms at differing ages, but everyone will eventually understand what I am describing. The main factor that determines an individual’s severity of arthritis is probably genetics; but tobacco use, weight, and abusing the body also play a role. The majority of people suffering back problems due to arthritic or age changes simply need encouragement and occasional anti-inflammatory medication. However there are more serious arthritic spine problems that can develop, such as stenosis.
Stenosis refers to narrowing or constriction around a neural structure, such as the spinal cord or a nerve. This occurs with arthritis because of bone spurs, which are like rust deposits in our analogy, developing around the affected joint. Think of the classic enlarged knuckle of the Wicked Witch of the West. With the hand knuckle, like most joints, the bone spurs simply interfere with the joint movement: which is actually their purpose. Your body is trying to “cure” the arthritis by fusing the joint with boney overgrowth. Once the joint is fused, it no longer moves, which means no more pain or irritation. Unfortunately that also means no more flexibility, which is very bad for elbows and knees but not as much a problem with the spine. In fact, the concern of “bone on bone” due to arthritis is not really a problem in the spine; it is almost a good thing. So in the spine the bone spurs can be helpful when they limit the irritation of movement, but the spurs are a problem when they pinch the adjacent nerves.
I have explained how the aging spine develops “rust” in the form of bone spurs, called osteophytes. These osteophytes can be problematic when they start to impinge on the nervous structures in a condition called stenosis. Stenosis can range from an asymptomatic finding on an xray, which means it is not causing any problems; to a devastating development including paralysis. The difference is in the degree of stenosis and what part of the spine is involved.
Cervical stenosis refers to the narrowing of the spinal canal in the neck. The spinal canal is the central opening in the spine through which the spinal cord and nerves travel on their way from the brain to all points of the body, particularly the arms and legs. An important anatomical concept to understand is that in the cervical spine, as opposed to the lumbar spine, the actual spinal cord is contained in this canal: not just nerves. The spinal cord is an extension of the brain, and is just as delicate and fragile as the brain. An injury to the spinal cord is irreversible and results in permanent damage. Furthermore the spinal cord in responsible for control of the entire body below that level. This means that injury to the spinal cord can result in total paralysis, not just weakness in a finger or toe. So problems like stenosis involving the cervical spine, again unlike the lumbar spine, can result in devastating problems such as quadriplegia.
The symptoms of cervical stenosis can be subtle and are often missed, even by health care providers. The misleading factor is that often there is no neck pain or discomfort. Patients will commonly respond to the news that they have cervical spinal stenosis with disbelief because they have no neck pain. Usual symptoms include numbness and clumsiness of the hands, and difficulty walking due to balance trouble. If the underlying stenosis is severe and not treated, the spinal cord injury will progress. This spinal cord injury is called myelopathy and can be seen on MRI. The time of progression is variable and can range from months to years. The patients with any worsening of their symptoms are in the greatest danger of rapid decline, while patients without symptoms sometimes will never get worse. However it is impossible to predict an individual patient’s future, so not treating severe stenosis is a risky gamble.
Another important aspect of cervical stenosis to remember is that damage to the spinal cord is permanent. There is often some improvement in the symptoms after surgery, but never complete recovery. This is why treatment of this process is indicated even if the symptoms are not terrible. This is also why it is generally not a good idea to see if the problem is going to get worse. If the patient waits until they can’t walk, then they will always be in a wheelchair despite having corrective surgery. So the risk of waiting and hoping that a person will not get worse is generally worse than the risk of surgery.
The risk of spinal cord damage is compounded by the fact that the spinal cord injury can be instantly worsened by trauma. This means that a car accident or a fall can result in instant and complete paralysis. Remember we are talking about a “disease” of aging, so the scenario is an older patient with balance problems due to cervical stenosis that could become completely paralyzed if they fall: disaster is almost inevitable. Unfortunately it is not uncommon to see just this situation in the emergency room: an older person now paralyzed after a seemingly minor fall. Even sadder is the patient will in retrospect realize they were having the warning signs of cervical stenosis: clumsy hands and balance problems. Now the patient has to undergo emergency surgery with little hope of ever walking again.
The only treatment for cervical stenosis, like the lumbar counterpart, is surgery. There are basically two options for surgery, anterior or posterior. Anterior surgery is the more common and involves an incision on the front of the neck. This procedure involves the removal of cervical discs, and sometimes actual vertebrae, and fusing the involved bones with grafts and plates. As I mentioned, this is the more common procedure and can often be done as an outpatient with fairly fast recovery. Of course operating through the front of the neck and around the spinal cord has many potential complications, but thankfully we have gotten quite good so there are rarely problems. The other option is a posterior approach, or through the back of the neck. This procedure is more like the lumbar counterpart in that a laminectomy is performed, which is to unroof the back of the spinal canal by removing bone. Often screws and plates are placed to strengthen the cervical spine after removal of all this bone. This approach may avoid the critical structures of the throat area, but there are more problems with blood loss and positioning. Even more rarely patients will need to have both an anterior and posterior surgery. There are many discussions amongst spine surgeons as to which approach is best, but the truth is that as long as the surgeon does a good job, they all work well. As with any surgery, every patient is unique so there is no one surgery for all patients. Again it is important to make the diagnosis of cervical stenosis before it is too late.
Lumbar stenosis refers to the narrowing of the spinal canal in the low back area of the spine. The spinal canal is the central opening in the spine through which the spinal cord and nerves travel on their way from the brain to all points of the body, particularly the arms and legs. An important anatomical concept to understand is that in the lumbar spinal canal there are only nerves, not the spinal cord. The nerves are much stronger and more resilient than the spinal cord, and the consequences of their being pinched are less. The classic problem associated with lumbar stenosis is pain in the back and legs associated with the standing position. Often the complaint is described as a heavy feeling or numbness, and sometimes it is only in the legs. The key component of the syndrome is that the problem is relieved upon sitting and bending over. These are the people walking hunched over a grocery cart or leaning on a cane, and taking frequent sitting breaks in the mall. As long as they sit or lean forward for a few minutes, the pain is relieved and they can continue for a short distance.
Patients with lumbar stenosis usually develop complaints over years, reaching a point that they can no longer stand or walk for more than a few minutes. There is rarely any urgency to treating lumbar stenosis as it usually only causes discomfort and not paralysis. This means that if someone develops sudden back problems and is found to have lumbar stenosis, the stenosis may not be the real issue. If a person develops sudden back problems it may be a “flare-up” of their underlying stenosis, or simply a strained back, and they will get better with supportive measures and not need surgery. On the other hand, the only way to “fix” lumbar stenosis is with surgery. Conservative measures such as traction, physical therapy, chiropractic care, medications, injection, etc. may temporarily easy the symptoms but they won’t change the anatomy. Therefore if the patient has progressively worsening problems and is not having adequate relief with these alternatives, surgery should be considered.
There are a variety of surgical options to treat lumbar stenosis. The goal of all the surgeries is simply to open up the spinal canal so the nerves are not too tight, or pinched. The original procedure was a lumbar laminectomy, which was to remove the back part of the vertebrae and unroof the spinal canal. This is very effective, but can be a large operation if there are multiple levels of concern. Furthermore, removing this much bone can weaken the spine and occasionally leads to other problems. A new technique was developed to try and avoid these issues, the minimally invasive microlaminotomy. This procedure is performed through a small incision and creates a window in the bone through which the spinal canal can be accessed and cleaned out: almost a “roto-rooter” technique. The reason this surgery can work is because the nerves are usually being pinched more by thickened ligaments than by actual bone, and the pinching is occurring in a focused area. There are even newer techniques that are called minimally invasive that involve placing various implants in the spine to try and stretch these ligaments, but the long term success of these procedures is not known and the surgery to place these implants is not always so minimal. Every patient’s anatomy is unique, so there is no one right surgery for all. The good news is that if surgery is needed there are options available that may not involve a “major” surgery and extended recovery.