Carpal Tunnel Syndrome: What it is and how to measure it

This article is intended for medical providers and others who are interested in carpal tunnel syndrome that is caused by workplace activity.Carpal Tunnel Syndrome

What is carpal tunnel syndrome, exactly?

Carpal tunnel syndrome, or CTS, is caused by pressure on the median nerve in your wrist. The median nerve travels from the forearm through the carpal tunnel into the hand.

What are the symptoms of CTS?

  1. Numbness
  2. Tingling
  3. Weakness
  4. Shooting pain

For further reading on the symptoms of CTS, check out this Mayo Clinic article.

How often does CTS occur?

A lot. According to the American Academy of Family Physicians, Carpal Tunnel Syndrome (CTS) occurs in approximately 3-6% of the adult population.

While CTS can be caused by genetics, diabetes, and pregnancy one major factor can be repetitive, forceful movement. As a result, CTS is a very common workplace injury.

How to measure CTS for an impairment rating

When CTS is caused by work related activities, and if an employee is permanently impaired due to CTS, then the condition requires an impairment rating.

Like all injuries, calculating an accurate impairment rating for CTS requires measurements that can be reproduced. In other words, it’s important the medical providers measure CTS in their patients multiple times to ensure that another provider would obtain the same measurements.

In California (and many other states), all impairment ratings for work-related injuries should be calculated according to the AMA Guides, 5th edition.

According to the Guides, the objective factors that affect the PR-4 impairment rating include sensory loss, grip and pinch loss, and loss of range of motion.

If you’ve used RateFast to write a PR-4 report for an injury to your patient’s wrist, then you probably remember being prompted to measure each of these factors.

CTS Factors and Measurement Tools

  • Sensory loss should be measured with two-point discrimination and monofilament testing using the Semmes Weinstein monofilaments.
  • You can measure grip and pinch loss with a dynamometer.
  • Measure the patient’s loss of range of motion with a goniometer. (Check out the RateFast Goniometer app, available for iOS and Android.)

Remember to use the proper devices to take all measurements twice to make sure your findings are compliant with the AMA Guides. When medical providers don’t take multiple measurements, then their PR-4 report will be incomplete. The result is often an inaccurate impairment rating—which can result in happy insurance carriers and unhappy patients.