Could a Leg Test Help to Diagnose Your Back or Neck Pain?

In conjunction with World Spine Day, October 16, 2021 we discuss some of the useful techniques in diagnosis of back and neck pain with an Inova Spine expert.

John Hamilton MD, PhD, serves as the Medical Director of the Inova Peripheral Nerve Program, Inova Health System; Medical Director of the Inova Spine Program at Inova Fairfax Hospital; Section Chief, Neurosurgery at Inova Fairfax Hospital; and as a physician in the Inova Neurosurgery practice. He is on the faculty team for Inova’s neurosurgical residency program and is an Associate Professor in the department of neurosurgery at Virginia Commonwealth University School of Medicine, Inova campus.

When it comes to back or neck problems, you might think that a doctor who specializes in treating spine conditions will diagnose the cause with a medical history, X-ray or MRI scans, and a physical examination only. You might be surprised to learn that sometimes, the spine doctor goes beyond back and neck testing and examination to look at leg pain and may perform a straight leg test as well.

That’s because some back and neck conditions cause symptoms not just in the back or neck, but in the legs and feet as well. In order to discover the source of the pain, numbness, tingling, or weakness in the lower body, the straight leg test can provide vital information about how the spine might be involved in the symptoms.

The 26 bones that form our spinal column provide stability and flexibility, which allow us to stand up and move. Those bones also help to protect the nerve bundles in the spinal cord, which lead down from the brain and branch out to connect every part of the body. Because of those nerve connections, pinched or damaged nerves in the spinal cord sometimes result in symptoms in the leg or foot.

What is a straight leg test, and how does it help to diagnose a back or neck problem?

“A straight leg test is a way to determine if there is any pressure or irritation in the lower lumbar nerves, the nerves in the lower back. When the spinal nerves are compressed or constricted, they can become irritated and inflamed, causing pain, numbness, tingling, and weakness,” said John Hamilton, MD, PhD, Medical Director of the Inova Peripheral Nerve Program, Inova Health System, Co-Medical Director of the Inova Spine Program at Inova Fairfax Hospital, Section Chief, Neurosurgery at Inova Fairfax Hospital.

The test is simple. The patient sits or lies down on the exam table, then extends the leg out straight. “If the patient feels pain that shoots down the leg when it is extended, that indicates a problem with the spine,” Dr. Hamilton said.

To test nerves a little higher up within the spine’s lumbar region, the spine specialist might conduct a reverse straight leg test. During a reverse straight leg test, the patient lies flat on the stomach, and the leg is gently pulled back, so it is extending up off the table. A shooting pain means that the leg pain is caused by compression of the nerve roots, where the nerves branch out of the spine. The compression, or pinching, can be the result of many spine problems, including a herniated disc, spinal stenosis, spondylolisthesis or other issues, and your doctor will determine the exact cause and discuss your treatment options with you.

Is your foot problem really a back problem?

Foot drop is another condition that may have its cause not in the foot, but in the spine. “Individuals with foot drop have weakness in the muscles that pick the foot up, and as a result, they can’t pick up their foot normally. Instead, it slaps on the ground. To prevent themselves from tripping, they tend to compensate by lifting their leg high in an exaggerated step, which is called a high-steppage gait,” Dr. Hamilton said.

Foot drop can be caused by an injury to a nerve near the knee, part of the peripheral nerve system. Another likely culprit is a nerve in the lower back. A straight leg test can identify whether a pinched peripheral nerve or a nerve in the lumbar spine is causing the foot drop.

Dr. Hamilton explains, “The nerves in the foot branch out of the lumbar spine and extend down the legs. In order for the end organ – which in this case is the muscle that lifts the foot – to work properly, the nerves all along the road from the spine to the foot have to work properly. If part of the nerve isn’t functioning, you’ll see it in the motor function.”

Getting a straight leg test

To get a solid diagnosis using a straight leg test, it’s important to consult a spine and peripheral nerve expert. “Board-certified neurosurgeons with experience in both spine and peripheral nerves are best equipped to manage diseases that involve the central and peripheral nerve system,” Dr. Hamilton said. “Neurosurgeons are trained to deal with nerves in a careful manner. A neurosurgeon who specializes in spine is experienced in dealing with soft tissue, including the nerve tissue and nerve roots, as well as the bony spine.”

Inova Spine Program’s team of dedicated spine experts use the full range of nonsurgical treatment options to treat back and neck conditions, including physical therapy and medications for relief. If surgery is the right course of action, our patients benefit from access to the best therapies and technologies available – including minimally invasive surgical treatments with robot-assisted and augmented reality equipment. Our spine surgeons have met strict standards in technical qualifications and case volumes, and our nonsurgical clinicians have the highest level of technical training in their areas of expertise.

Prompt evaluation leads to better outcomes

Early evaluation and diagnosis is critically important for nerve injuries. For example, if foot drop is not resolved within 9 to 12 months of the start of symptoms, it can cause permanent disability to the foot, making it impossible to run and putting individuals at risk of frequent falls.

“My advice for patients, particularly if you have foot drop, is, do not wait,” Dr. Hamilton said. “If you are having symptoms, seek a spine surgeon’s review and opinion and get the workup started. That doesn’t mean you’ll need surgery – 80 to 90 percent of the time, you won’t. But in order to have a good outcome, it needs to be treated promptly.”

To speak with an Inova neurosurgeon trained in spine and peripheral nerve and/or to request a second opinion, contact Inova Neurosurgery or call 571-472-4100.