What is Spinal Stenosis?
The organization of the spine includes the vertebral body in the front and the lamina in the back. The front and back of the spine are connected by the pedicle. The bodies are separated by a disc and the lamina are connected by the facet joint.
The discs and facet joints allow the spine to flex, extend, turn and bend to the side. The discs in the front of the spine support and allow movement between the vertebral bodies. The facet joints are in the rear of the spine and these small fluid filled joints allow the facet bones to slide back and forth with minimal resistance.
Spinal stenosis is the narrowing of the spinal canal. As people age, the discs dry out and collapse. The body stiffens the spine by thickening the spinal ligaments and hardening the disc and facet joints form bone spurs.
Unfortunately, these changes result in the narrowing of the spine canal and compression of the spinal cord and/or nerves and blood vessels. This decreases the blood supply and oxygen to the nerves producing arm or leg pain. The brain thinks the arm or leg are the cause of the pain when it is actually the pressure in the back or neck.
Spinal stenosis usually develops in patients over 40 years old, however I have seen in it become severe in some patients in their 20s. It is characterized by slowly worsening back, arm and leg pain, numbness, tingling and weakness. Patients that I have spoken with describe pain and discomfort that usually gets worse with standing and/or walking. Those patients start to notice that they tend to walk with a forward flexed posture because of the pain. They also find that they can walk a bit farther and alleviate the pain by bending forward while leaning on a shopping cart or by sitting down. Patients with cervical (neck) stenosis notice that they can make their painful symptoms worse by positioning their neck and then relieve the pain by changing their neck position. The change in position and relief or worsening of symptoms is due the decrease or increase in compression of the nerve due to the stenosis. Rarely patients may develop urinary and bowel incontinence or retention. If this happens they should emergently contact their doctor.
I have found that most patients with these symptoms modify their life around what they are now able to tolerate. Meaning that they will start to walk shorter distances, use a motorized chair at a grocery store, limit going for a walk and generally start the process of becoming deconditioned and less able to tolerate exercise.
How is this Diagnosed?
MRI scan is the best test to see if spinal stenosis is compressing the nerves. CT scan or CT myelogram (contrast dye injected into the spinal canal) is usually reserved for patients who cannot have an MRI. EMG (electromyelography) can occasionally help confirm nerve irritation and injury.
Most patients start the treatment process by trying physical therapy and/or chiropractic care. Other options my patients have tried include Tai Chi and acupuncture. The next step is often trying an epidural steroid injection. These can be done to directly target the area of stenosis. The effect is that the pain is usually improved for a period of time and then returns. The second injection doesn’t usually last as long as the first but is generally reasonable to perform. When conservative measures fail or the stenosis is severe, or weakness and/or a progressive neurologic deficit is present then surgery is a great option to obtain relief.
Surgery usually involves a simple decompression called a hemilaminectomy. This involves removing a portion of the lamina to access the spinal canal and decompress the nerves that course along the facet joint where the bone spurs develop. I have developed a technique that allows me to decompress the foraminal, lateral, central and para-central stenosis on both sides of the canal from a unilateral one-sided approach.
This makes the recovery process easier for the patient because surgery is only done on one side of the spine but I am able to decompress both sides of the spinal canal. Many surgeons perform surgery on both sides which unfortunately requires placing a retractor or tube style retractor through the multifidus muscles. Endoscopic spine surgery procedures have also been developed to remove the bone spurs. The beauty of this procedure is that it is commonly done through an incision less than one centimeter or slightly more than 3/8ths of an inch.
The reason that I try to consider patients for an endoscopic approach to treat their problem is that is a muscle sparing “ultra” minimally invasive approach. The concept of this one-sided approach and endoscopic method of treating spinal stenosis is much different than traditional spine surgery.
Traditional surgery is more destructive in the approach to the spine compared to minimally invasive surgery. The larger the incision the more damage to muscle, ligaments and bone. This collateral tissue damage may result in more pain, back muscle weakness, instability and scar tissue leading to future difficulties. Fortunately, traditional surgical techniques are often avoidable depending on the spine surgeon’s techniques.
New extremely minimally invasive endoscopic spinal surgeries are being developed for the treatment of spinal stenosis (as shown below). The advantages of these procedures will include no general anesthesia, very small incision (size of finger nail), minimal postoperative pain and shorter recovery then current minimal invasive spine surgery.