Spinal Canal Narrowing (Lumbar Stenosis)

Lumbar spinal stenosis is narrowing of the spinal canal in your lower back, leaving less room for the nerves. It's the most common reason patients over 65 end up needing spine surgery. The narrowing builds up over decades from the same group of normal aging changes, the discs thin out, the small joints in the back of the spine enlarge, and the ligaments inside the canal thicken. None of those changes is dramatic on its own; together they slowly squeeze the space the nerves run through.

The hallmark symptom is a distinctive pattern called neurogenic claudication: aching leg pain, heaviness, or numbness that comes on after you've been walking or standing for a few minutes, and that gets better as soon as you sit down or lean forward (the "grocery cart sign," because patients often instinctively lean on a shopping cart for relief). That positional pattern is what distinguishes stenosis from leg pain caused by poor circulation, which improves with rest regardless of body position.

The hallmark is leg pain, heaviness, or numbness that builds after you walk or stand for several minutes and then eases as soon as you sit down or lean forward. Many patients instinctively lean on a shopping cart for relief, the "grocery cart sign." Your walking distance gradually shrinks over months to years as the canal narrows further. Low back stiffness and aching are common but usually take a backseat to the leg symptoms.

Symptoms can affect one or both legs and may include tingling, a "pins and needles" sensation, or a feeling that your legs are about to give out. Uphill walking and cycling (both slightly forward-bent postures) tend to be easier than walking on flat ground or downhill. Emergency: sudden bilateral leg weakness, saddle-area numbness, or loss of bladder or bowel control warrants an immediate trip to the emergency department.

MRI shows how narrow the canal has become and at which levels, that determines which nerves are likely involved. A CT myelogram (a CT scan with contrast injected around the cord) is used when MRI isn't an option. In older patients with leg symptoms, your provider will also screen for poor circulation in the legs (with a simple blood-pressure measurement at the ankles), the symptoms can mimic stenosis and need different treatment. Critically, the diagnosis is a clinical one, imaging findings have to match your symptom pattern.

The good news is that most people improve with a structured non-operative plan, and the pieces build on each other rather than replacing one another. The common thread is simple: positions that bend you slightly forward open up the narrowed segments and take pressure off the nerves, so the plan leans into that. Here is the order we usually work through.

If Conservative Care Is Not Enough

When the conservative steps above have not given enough relief, an interventional treatment such as an epidural steroid injection placed around the compressed nerves is often the next step. OSI does not perform spinal injections. When that step is appropriate, OSI directs you to a pain management specialist who provides interventional treatment, and your evaluation and conservative care stay with us.

Surgery helps only a small minority of spine patients, usually those with a specific structural problem plus a nerve issue that isn’t getting better with a structured non-operative trial. When that step is genuinely warranted, it falls outside the care OSI provides, so we refer you to a spine surgeon. OSI does not perform or coordinate spine surgery; your non-operative care stays with us.

Emergency. Bilateral leg weakness, saddle numbness, or loss of bladder or bowel control is a surgical emergency, go to the nearest emergency department rather than waiting for a clinic appointment.

External patient-education references and related OSI pages for additional background:

• AAOS OrthoInfo, patient education library
• OSI glossary, orthopedic terminology in plain language