In broad terms, our spine is made up of bony structures called vertebrae, joints, tough ligaments, and rubber-like cushions called discs that sit between the vertebrae. These discs allow movement and act like shock absorbers, taking the load coming from the upper levels and transmitting it smoothly to the lower levels. Together, these structures form a canal that surrounds and protects the spinal cord as it passes through them. At the lumbar (low back) level, the spinal cord carries the nerves that provide sensation and strength to the legs. Narrowing of this canal, through which the spinal cord passes, for various reasons is called lumbar spinal stenosis, in other words “lumbar canal stenosis.”
WHAT ARE THE CAUSES OF LUMBAR CANAL STENOSIS?
In people who do heavy physical work, those who overload their spine (being overweight, lifting weights improperly, etc.), those with a genetic predisposition, and in advanced age—especially after the age of 50—the discs lose their elasticity, the ligaments and joints thicken, and the bony structures become rougher and calcified (degenerative changes). The alignment (axis) of the spine can also deteriorate. This whole degeneration process can lead to narrowing of the spinal canal and compression of the spinal cord and nerves passing through it. Lumbar canal stenosis can also occur as a result of trauma, most often due to vertebral fractures. Tumors or other diseases can likewise cause narrowing of the lumbar canal.
WHAT ARE THE SYMPTOMS OF LUMBAR CANAL STENOSIS?
Patients typically describe their complaints as: “After walking for a while my legs go numb, I feel drained, it feels like there is no life in my legs, as if I’m not in control of them, and I start looking for a place to sit; I feel like I’m going to fall.” This complaint is called “neurogenic claudication.”
It most commonly involves the L3–L4 levels. Sometimes it appears at a single level, but more often at multiple levels.
Because the symptoms are similar, lumbar canal stenosis is often confused with a lumbar disc herniation (slipped disc). Lumbar disc herniation and lumbar canal stenosis are different diseases, although they may occur together.
Canal stenosis can also progress without causing any symptoms. Symptoms of lumbar canal stenosis include numbness in the legs, muscle cramps, weakness, tingling, and pain. The most striking feature of canal stenosis is that the condition is generally progressive.
In a lumbar disc herniation, a single nerve root going to the leg on the right or left at that level is compressed, whereas in canal stenosis all the nerves going to the legs are compressed at the same time. For this reason, numbness usually occurs in both legs. In disc herniation, leg pain is the predominant symptom; in canal stenosis, numbness in the legs and reduced walking distance are more prominent. Disc herniation is seen more often in young and middle-aged adults, while canal stenosis is generally seen in older individuals. With canal stenosis, patients usually have no pain at rest, whereas in disc herniation the pain continues even at rest. Because it reduces their symptoms, some patients with canal stenosis prefer to walk leaning forward.
As in advanced lumbar disc herniation, patients with lumbar canal stenosis may also develop problems such as loss of bladder and bowel control.
HOW IS LUMBAR CANAL STENOSIS (LUMBAR SPINAL STENOSIS) DIAGNOSED?
In lumbar canal stenosis, the patient’s history is the most important element. After clinical examination and assessment of the patient’s complaints, the diagnosis can be confirmed with radiological imaging. With Magnetic Resonance Imaging (MRI) and/or Computed Tomography (CT), the diagnosis of lumbar canal stenosis can be definitively established.
HOW IS LUMBAR CANAL STENOSIS (LUMBAR SPINAL STENOSIS) TREATED?
Treatment of lumbar canal stenosis varies depending on the patient’s overall condition and the stage of the disease. If lumbar canal stenosis is not at an advanced stage, non-surgical treatments come to the forefront.
With physical therapy, the muscles in the lumbar region can be strengthened, flexibility can be improved, and muscle pain can be reduced. Painkillers, muscle relaxants, and in patients with nerve compression pain, medications for so-called neuropathic pain can be used to control symptoms.
In particular, in patients who are not suitable candidates for surgery, injection therapies can give good results. By injecting ozone, cortisone, or similar agents into the stenotic area of the lumbar canal, swelling (edema) and inflammation in the nerve tissue and surrounding tissues are reduced. Injection treatments can be repeated up to three times a year.
In patients who do not benefit from non-surgical treatments, whose pain cannot be controlled, who have neurological muscle strength loss, and especially in those who cannot walk 100 meters without stopping, surgical treatment is indicated.
HOW IS LUMBAR CANAL STENOSIS SURGERY PERFORMED?
The goal of lumbar canal stenosis surgery is to relieve the compression on the spinal cord and nerves and to decompress the narrowed canal using surgical techniques.
If there is no other problem in the area of lumbar canal stenosis, surgery is performed from the back (posterior) of the spine. At the level where calcification or other causes have narrowed the canal, the part of the vertebra called the lamina, and when necessary part of the facet joints and the surrounding ligamentous tissue, are removed.
Depending on the level of stenosis, the patient’s age, accompanying diseases, the severity of the narrowing, and associated spinal deformities (such as instability—abnormal movement like spondylolisthesis—or scoliosis), surgery can be performed with instrumentation (metal devices, commonly referred to as “plates or rods” by the public) or without implants.
After the decompression (relief) procedure is done and adequate canal widening is achieved, if the spine becomes unstable enough to lose its balance, balance must be restored with implants.
HOW LONG DOES LUMBAR CANAL STENOSIS SURGERY TAKE?
The duration of lumbar canal stenosis surgery can vary depending on the severity of the stenosis, how many levels are involved, and the condition of the muscles and bones. If the stenosis is at a single level and implants such as screws are used during the operation, the surgery may take about 1.5–2 hours. If no implants are required, the surgery usually takes around 1 hour. However, if the stenosis involves 3–4 levels and implants must be placed over 4–5 levels, the surgery may take approximately 5–6 hours.
WHAT ARE THE RISKS OF LUMBAR CANAL STENOSIS SURGERY?
Like any surgical procedure, lumbar canal stenosis surgery carries risks. To minimize these risks and avoid complications, it is very important that the operation is performed by an experienced team in this field. Possible risks can be summarized as follows:
As with any surgery, there is a risk of postoperative infection.
Because lumbar canal stenosis surgery is most often performed in elderly patients, wound healing problems may occur. In older patients, conditions such as hypertension, diabetes, and heart disease increase risks both for anesthesia and in the postoperative period.
The bone or calcified soft tissues removed during surgery to relieve the compression may be adherent to the dura (the membrane around the spinal cord). Although uncommon, tears in the dura can occur. This risk is higher especially in patients undergoing a second or third lumbar canal stenosis surgery. A dural tear is a condition that can be repaired during the operation; however, sometimes cerebrospinal fluid can leak from this tear, which may cause problems in the postoperative recovery period.
After lumbar canal stenosis surgery, patients may experience complaints such as numbness, tingling, and altered sensation. It is not expected that previously existing numbness will resolve immediately after surgery, and these symptoms may continue for some time. They should not become permanent.
In fusion surgeries where implants such as screws or cages are used, difficulties in bone fusion may occur depending on the patient’s bone quality. In elderly patients, because bone quality is often poor, fusion problems can later lead to loosening of screws. Where appropriate, cemented screws are generally preferred.
WHEN CAN A PATIENT RETURN TO NORMAL LIFE AFTER LUMBAR CANAL STENOSIS SURGERY?
The time it takes for patients to return to their normal daily life after lumbar canal stenosis surgery can vary from person to person. Factors such as the patient’s activity level and the type of work they do are important.
The patient is usually mobilized—helped to walk—on the same day or the day after surgery. Depending on the type of operation, patients can go outside 1–2 weeks after canal stenosis surgery. During this time, walking distance can be gradually increased. About 4 weeks after surgery, patients can return to work, provided they follow certain movement restrictions. Full healing usually occurs after about 6 months; this is also the time it takes for any tissue in the body to reach full strength.
Especially in patients who have had implants placed, they must be careful to avoid prohibited movements until bony fusion is complete. They should avoid heavy lifting and movements such as bending forward, backward, or sideways in an uncontrolled way or twisting at the waist.
WHAT SHOULD BE CONSIDERED AFTER LUMBAR CANAL STENOSIS SURGERY?
After discharge, if the patient notices discharge from the wound, opening of the wound edges, new-onset severe pain that was not present before, or new weakness in the legs, they should contact their doctor.
In particular, after surgeries where implants such as screws are used, an increase in pain that had previously decreased may indicate infection or loosening of the screws. If there is a change from a pain-free to a painful period, the patient should consult a doctor without delay.
In addition to pain, redness, discharge from the wound, and fever may be signs of infection.
In some patients who have lumbar canal stenosis in the lumbar spine, there may also be canal stenosis in the cervical (neck) spine. Patients should be aware of this possibility as well.