The experience of pain in both legs when walking, known as claudication, points toward two distinct underlying problems: inadequate blood flow or compression of the spinal nerves. This activity-triggered discomfort signals that the muscles or nerves are not receiving the resources needed to sustain movement. Understanding the difference between these two categories, vascular and neurogenic, is the first step toward finding relief and seeking an accurate diagnosis.
Peripheral Artery Disease (PAD)
Peripheral Artery Disease is a vascular condition where the arteries supplying blood to the limbs become narrowed, most commonly due to atherosclerosis. This narrowing restricts blood flow, leading to a shortage of oxygen and nutrients for the leg muscles during physical exertion. When the muscle demand for oxygen increases during walking, the restricted supply causes pain, which is described as a deep ache, cramping, or fatigue.
This discomfort from PAD, often referred to as vascular claudication, consistently begins after a specific distance of walking and is relieved within a few minutes of stopping the activity. The relief is achieved by resting and does not require a change in body position, such as sitting or leaning. The pain is usually concentrated in the calf muscles, but it can also be felt in the thighs or buttocks.
A primary cause of PAD is the buildup of plaque (fatty deposits and cellular debris) on the artery walls, a process called atherosclerosis. Smoking is the most significant risk factor, damaging the artery lining and promoting plaque formation. Other medical conditions that accelerate plaque buildup include diabetes, high blood pressure (hypertension), and high cholesterol levels.
Spinal Stenosis and Nerve Compression
When leg pain is caused by nerve compression in the lower back, it is known as neurogenic claudication, and the most common cause is lumbar spinal stenosis. Spinal stenosis involves the narrowing of the spinal canal, which reduces the space available for the spinal nerves traveling to the legs. This mechanical compression of the nerves is often exacerbated when the spine is extended, such as in an upright standing or walking posture.
The symptoms of neurogenic claudication are distinct from vascular issues, often presenting as burning, tingling, numbness, or weakness that can radiate from the buttocks down into the legs. Relief involves the pain easing when the individual changes posture, such as by sitting down or leaning forward over a shopping cart. This flexion posture widens the spinal canal and temporarily relieves the pressure on the compressed nerves.
Degenerative changes associated with aging, like the overgrowth of bone or thickened ligaments, are the primary drivers of this narrowing. The symptoms are brought on by walking or standing, but they improve with spinal flexion. This positional change is the key differentiator from vascular claudication.
Diagnosis and Initial Management
Differentiating between vascular and neurogenic claudication begins with a clinical interview, focusing on the patient’s symptoms and the specific actions that provide relief. The positional nature of the pain—whether it is relieved by rest (vascular) or by sitting or leaning forward (neurogenic)—provides the first strong clue. A physical exam will also include checking the pulses in the feet, as diminished pulses can indicate poor blood flow associated with PAD.
To confirm a diagnosis of PAD, the Ankle-Brachial Index (ABI) is the first-line diagnostic test, which is a comparison of the blood pressure in the ankles to the blood pressure in the arms. An ABI value of 0.90 or lower strongly suggests the presence of Peripheral Artery Disease. If the ABI is normal or borderline, an exercise treadmill ABI test may be performed to reveal a reduction in blood flow that only appears during exertion.
For suspected spinal stenosis, imaging tests like Magnetic Resonance Imaging (MRI) or Computerized Tomography (CT) scans are used to visualize the spinal canal and confirm the degree of nerve compression. These images help identify the source of the narrowing, such as a bulging disc, bone spurs, or thickened ligaments.
Initial management for both conditions emphasizes conservative, non-surgical approaches and lifestyle modifications. For PAD, a supervised exercise program is recommended, as it can help the body develop collateral circulation to bypass blockages. Lifestyle changes, such as smoking cessation, maintaining a healthy weight, and controlling high blood pressure and diabetes, are important for slowing the progression of PAD.
For spinal stenosis, initial management often includes physical therapy to improve strength and flexibility in the back muscles. Medications, such as Nonsteroidal Anti-inflammatory Drugs (NSAIDs) or anti-seizure drugs like gabapentin, can help manage pain and nerve-related symptoms. Injections of a steroid medicine into the space around the pinched nerve may also be used to temporarily reduce inflammation and swelling.