Living with diabetic neuropathy often means dealing with burning pain, tingling sensations, and numbness that affect your daily activities. While you may have been told these symptoms are just part of having diabetes, there could be more to the story.
Many patients diagnosed with diabetic neuropathy and who are only offered medical therapy or no therapy at all, may actually be experiencing nerve compressions that can be treated surgically. Baltimore peripheral nerve surgeon Dr. Eric H. Williams has helped many patients with nerve compressions related to diabetic neuropathy—and he may be able to do the same for you.
The Tinel sign test is one tool Dr. Williams uses to determine if a nerve compression may be causing a patient’s symptoms. This simple test, which you can do from the comfort of your own home, could be the first step toward finding relief from your symptoms.
What Is the Tinel Sign Test?
Named after French neurologist Jules Tinel in 1915, the Tinel sign test involves lightly tapping along the path of a nerve. When the tap produces tingling or an electrical sensation that travels along the nerve's pathway, it indicates potential nerve irritation or compression at that location. This sensation is similar to the familiar "funny bone" feeling you get when bumping your elbow.
The test is valuable because:
- It can detect nerve problems before they become severe.
- It helps locate the potential point of nerve compression.
- It can track nerve regeneration after injury.
- It assists in distinguishing between different types of nerve disorders.
- It serves as a useful screening tool for various compression neuropathies.
The test works because compressed nerves become more sensitive to mechanical stimulation. When tapped, these irritated nerves send signals that create distinctive sensations in the areas they supply. For someone with diabetic neuropathy, a positive Tinel sign suggests that nerve compression may be contributing to their symptoms. This has been supported by several peer-reviewed studies performed by different physicians in different settings across the world.
How to Check for a Tinel Sign
You can perform a basic version of the Tinel sign test yourself by:
- Sitting with your limbs in a relaxed position
- Using your fingertip to tap gently along suspected nerve compression sites
- Moving slowly along the path where you feel symptoms
- Noting where you feel tingling or "electric shock" sensations—keeping in mind that the intensity of the sensation doesn’t necessarily indicate a more severe nerve compression
- Comparing the sensation to the same spot on your other side
However, home testing has limitations. While you might not feel a clear Tinel's sign at home, a negative home test doesn't rule out nerve compression. Dr. Williams may be able to find it because of his understanding of nerve anatomy and experience correlating the precise pattern of symptoms to identify specific nerves to test. If you have symptoms that suggest nerve compression, we encourage you to visit our office even if you are unable to find a Tinel sign at home.
Why Diabetes Creates Nerve Compression
Diabetes creates perfect conditions for nerve compression through several mechanisms:
- Nerve swelling. High blood sugar causes nerves to absorb extra fluid and swell, similar to a sponge soaking up water. This swelling makes nerves more susceptible to compression as they run through tunnels to get to their end organs—the hands and feet.
- Tissue changes. Diabetes affects the connective tissue surrounding nerves, making it less flexible and more likely to create pressure points. The tissue may become stiffer and tighter. Therefore the tunnels that the nerves travel through get smaller and stiffer. This sets up the possibility of a swollen nerve running through a very tight space.
- Chemical effects. The conversion of excess glucose to sorbitol within nerves creates additional swelling and pressure. This process helps explain why even well-controlled diabetics may experience nerve compression symptoms.
Peripheral nerve decompression surgery can relieve nerve entrapment, restore axonal transport and blood supply in the nerve, relieve numbness and pain, and promote tissue repair, but it cannot eliminate peripheral neuropathy caused by abnormal glucose metabolism. Therefore, insulin should still be used to control blood sugar stability and to improve metabolic disorders in diabetic patients.
Key Testing Sites and Affected Nerves
Understanding which nerves are commonly affected by diabetes helps explain why symptoms appear in specific areas. Let's explore the main nerves we test, their functions, and what happens when they're compressed. (Please keep in mind that patients can have multiple nerve compressions, so you may want to try the Tinel sign test in more than one area.)
Tibial Nerve at the Tarsal Tunnel
The tibial nerve is like the main power line for your foot's feeling and movement. It runs behind your inner ankle through a narrow tunnel created by bone and soft tissue, similar to a cable running through a conduit. This nerve has three crucial jobs:
- Controlling most of the feeling in your sole
- Powering the small muscles that help maintain your arch and move your toes
- Controlling your foot's sweat glands
When the tibial nerve is compressed, patients typically experience:
- Burning pain or numbness in their heel, arch, and sole
- Difficulty gripping with their toes
- Changes in foot temperature or sweat patterns
- Increased risk of unnoticed injuries due to numbness
- Loss of balance and spatial awareness, especially in the dark
Common Peroneal Nerve at the Knee
Think of the common peroneal nerve as your foot's "lifting specialist” and ankle stabilizer. It wraps around the fibula bone just below your outer knee in a vulnerable position—similar to a rubber band stretched around a pencil. This location makes it particularly susceptible to compression.
Its main responsibilities include:
- Lifting your foot up when you walk (dorsiflexion) or preventing your ankle from rolling under (inversion sprain)
- Providing sensation to the top of your foot and outer shin
- Controlling the muscles that help you balance
Common peroneal nerve compression can lead to:
- Foot drop (inability to lift the foot)
- Frequent tripping or stumbling
- Weakness when trying to lift the toes
- Numbness or tingling on the top of the foot
- A slapping sound when walking as the foot hits the ground
Deep Peroneal Nerve on the Foot
After branching from the common peroneal nerve, this smaller nerve specializes in more precise movements and sensations. It runs down the front of your leg and across your ankle, similar to a wire running along the surface of your foot.
Key functions of the deep peroneal nerve include:
- Providing feeling between your first and second toes
- Controlling the muscles that lift your toes
- Helping with balance through position sense
Compression symptoms include:
- Burning sensation across the top of your foot
- Numbness between the big toe and second toe
- Pain that worsens with tight shoes
- Difficulty lifting toes while walking
Making Treatment Decisions
When the Tinel sign is positive in a diabetic patient with well-controlled blood sugar, surgical nerve decompression may offer significant relief. The procedure creates more space around the compressed nerve, allowing it to function more normally and potentially reducing or eliminating pain.
Are you a good candidate for diabetic neuropathy nerve decompression surgery? Dr. Williams will consider several factors when planning treatment:
- Your overall health status
- Blood sugar control levels
- Circulation in the affected area
- The severity and duration of your symptoms
- Previous treatments you've tried
Success Rates and Recovery Expectations
Research shows encouraging results for diabetic patients who undergo nerve decompression surgery after a positive Tinel sign. Approximately 80-85% of diabetic patients with a positive Tinel sign experience significant improvement after surgical decompression. This improvement often includes reduced pain, better sensation, and improved balance.
Most patients notice initial changes within the first few weeks after surgery. Pain relief typically occurs first, followed by a gradual improvement in sensation over several months. Some patients continue to see improvements for up to one year after surgery. Refer to the testimonials section of our website to learn about the results Dr. Williams has achieved for his patients.