Spinal stenosis is the narrowing of the spinal canal. As people age, the lumbar discs dry out and collapse. In response, the body stiffens the spine by thickening the spinal ligaments and hardening the disc and facet joints with bone spurs. Unfortunately, these changes result in the narrowing of the spinal canal and the compression of the spinal cord, nerves and blood vessels. This decreases the blood supply and oxygen to the nerves, which produces leg pain. The brain thinks the legs are the cause of the pain when it is actually the pressure in the back.
Spinal stenosis usually develops in patients between fifty and eighty years old. It is characterized by slowly worsening back and leg pain, numbness, tingling and weakness. The pain may be constant, but is usually brought on by walking (called neurogenic claudication) or certain positions. It is relieved by sitting, lying down or using a shopping cart. People sometimes feel like they are walking on a cloud or cotton wool or that their legs do not belong to them. On rare occasions, patients may develop urinary and bowel incontinence or retention. If this happens they should immediately contact their doctor and go to the emergency room.
An MRI scan is the best test to see if spinal stenosis is compressing the nerves. A CT scan or CT myelogram (contrast dye injected into the spinal canal) is usually reserved for patients who cannot have an MRI. EMG (electromyelography) nerve studies can help confirm nerve irritation and injury.
Are there surgical treatments for lumbar spinal stenosis?
Patients who have not responded to conservative treatment may benefit from surgical treatment. Traditionally a large skin incision was made over the spine, and the back muscles were retracted to expose the spine in order to remove the lamina bones and ligaments compressing the spinal nerves. This is called a laminectomy.
Traditional surgery is more destructive in the approach to the spine compared to new minimally invasive surgery. The larger the incision, the more damage to skin, muscle, ligaments and bone. This collateral tissue damage may result in more pain, muscle weakness, spinal instability and scar tissue, which may lead to future difficulties. Many surgeons recommend the addition of a bone fusion and instrumentation with screws and rods with a laminectomy, due to the increased chance of the spine falling apart in the future due to damage from the surgery.
Minimally invasive surgery is done through a skin incision less than 1-inch, but it is more than just a small incision. The surgery is done through a tube in between back muscles to decrease muscle damage and weakness caused by muscle retraction.
New “extremely” minimally invasive endoscopic spinal surgeries are being developed for the treatment of spinal stenosis. The advantages of these procedures will include twilight sedation, very small incision (size of finger nail), minimal postoperative pain and shorter recovery then current minimal invasive or traditional spine surgery.