Foraminal narrowing, known more formally as foraminal stenosis, is an abnormal reduction in the size of nerve channels associated with your spinal bones, called foramina. It is one form a larger disorder known as spinal stenosis. Like other forms of this disorder, foraminal stenosis has a number of potential causes and common treatments.
Foramina is the plural form of the word foramen. When nerve roots branch off from your spinal cord, they must have a way to pass through your spinal bones and continue on to the rest of your body. The spinal foramina, which form gaps between the rear sections of adjacent spinal bones (vertebrae), provide this passage. In addition to their proximity to your vertebrae, the spinal foramina pass near the intervertebral discs, which cushion your vertebrae and maintain proper spacing between them.
Foraminal Stenosis Causes
Foraminal stenosis occurs when some form of tissue intrudes upon the foramina and inhibits the normal passage of one or more spinal nerves. Conditions that can lead to this tissue intrusion include bone spurs that develop in association with spinal osteoarthritis, age-related enlargement of spinal bone and degeneration or herniation of one or more intervertebral discs. In addition to risks associated with advancing age, your risks for developing foraminal stenosis increase if you have any muscle- or bone-related problem in your spine. Foraminal stenosis and other forms of spinal stenosis most commonly appear in your neck or lower back.
Compression of a nerve root inside one of your foramina produces a nerve injury called a radiculopathy. In addition to pain, a radiculopathy can trigger various changes in your normal nerve function. Depending on the location of your stenosis, these changes can manifest in your arms or legs as burning or tingling sensations, muscle weakness and the classic “pins and needles” feeling associated with a form of abnormal nerve sensation called paresthesia.
Nonsurgical treatments for foraminal stenosis commonly include nonsteroidal anti-inflammatory drugs (NSAIDs) such as naproxen or aspirin, avoidance of activities that can worsen your condition, temporary use of a soft collar brace for stenosis in your neck, and home exercises or supervised exercises that strengthen your back or neck and help relieve nerve pressure. In some cases, your doctor may also inject the affected area of your back or neck with an anti-inflammatory medication called a corticosteroid, or an anesthetic that blocks the signals coming from a compressed nerve.
If your stenosis symptoms don’t respond to these nonsurgical approaches, your doctor may recommend a minimally-invasive surgical procedure called an endoscopic laminoforaminoplasty, or another procedure called a foraminotomy, which is used to widen a foramen that’s intruding upon a nerve. In some cases, the symptoms of foraminal stenosis closely mimic the symptoms of other nerve-related back or neck problems. Because of this, doctors sometimes don’t properly diagnose the disorder and end up recommending treatments that don’t improve foraminal stenosis symptoms.
Cedars-Sinai: Foraminal Stenosis
“International Journal of Medical Sciences”: Endoscopic Laminoforaminoplasty Success Rates for Treatment of Foraminal Spinal Stenosis – Report on Sixty-Four Cases
National Institute of Arthritis and Musculoskeletal and Skin Diseases: What Is Spinal Stenosis?
Merck Manual for Health Care Professionals: Nerve Root Disorders (Radiculopathies)