Tinel's sign (also Hoffmann-Tinel sign or Tinel's Test) is a way to detect irritated nerves. It is performed by lightly tapping (percussing) over the nerve to elicit a sensation of tingling or "pins and needles" in the distribution of the nerve. Percussion is usually performed moving distal to proximal.
This sign is commonly used in the evaluation of compression neuropathies, including carpal tunnel syndrome, cubital tunnel syndrome, anterior tarsal tunnel syndrome and symptomatic neuroma. It may also be used to monitor recovery following peripheral nerve injury or nerve repair.
Studies show that the diagnostic performance of Tinel's sign varies substantially between populations and clinical settings, and it is generally interpreted alongside other physical examination findings and electrodiagnostic testing.
History
Tinel's sign takes its name from French neurologist Jules Tinel (1879–1952), who wrote about it in a journal article published in October 1915. Previously, in 1909, Trotter and Davies published their findings that sensations elicited distal to the point of nerve resection are referred to the area or point of nerve resection; however they "failed to comment on the clinical relevance of their observation."
For example, when performed at the wrist in suspected carpal tunnel syndrome, percussion over the median nerve at the carpal tunnel may reproduce tingling in the thumb, index finger, middle finger, or radial half of the ring finger. This is in line with the sensation distribution of that nerve.
The most studied analysis of Tinel's sign is for carpal tunnel syndrome. One systematic review including 67 studies reported a median sensitivity of approximately 0.59 and specificity of approximately 0.80 for diagnosing carpal tunnel syndrome. As for all clinical diagnoses, it is vital to take into account the patient's symptom history.
Tinel's sign may also be elicited in other compression neuropathies, including cubital tunnel syndrome, tarsal tunnel syndrome, and Guyon canal syndrome. For these diagnoses, percussion over the affected nerve reproduces paresthesia in its sensory distribution, which varies depending on the suspected clinical diagnosis. It may be useful in identifying occipital neuralgia, superficial peroneal neuropathy, and symptomatic neuromas. An example of this would be during a median nerve injury at the wrist, where paresthesia may initially begin at the palm, but later advance down to the 1st-3rd digits during nerve recovery. This is because the distal nerve fibers undergo Wallerian degeneration after injury and new axons grow distally from the proximal stump, causing the most distal point along the nerve where percussion elicits paresthesia to move progressively toward the fingers.
This phenomenon has been used as an indicator of nerve regeneration following trauma or nerve surgery.
Limitations
The usefulness of Tinel's sign in a clinical setting is limited by the variability in diagnostic accuracy as well as differences in examiner technique. Previous studies that have evaluated carpal tunnel syndrome reported wide ranges in sensitivity and specificity. Because of this variability, the general consensus is that physical examination maneuvers alone are often insufficient to establish the diagnosis of compression neuropathies. Additional information from the patient history and tests such as electrodiagnostic studies should be used to confirm the diagnosis of peripheral nerve compression, and is required before getting carpal tunnel release surgery.
See also
- Hoffmann's sign
- Phalen maneuver