Carpal tunnel syndrome (CTS) is an injury to the median nerve in the wrist caused by engaging in repetitive activities. It is a common occupational injury that triggers workers’ compensation benefits. It causes numbness, weakness, and tingling in the fingers and palm. The actual cause of CTS is unknown.
The types of repetitive motion thought to cause CTS include:
- keyboard use
- the use of hand tools
CTS can be diagnosed through testing in a doctor’s office or through a nerve conduction study.
The treatment for CTS is:
- avoiding painful activities
- carpal tunnel release surgery
A carpal tunnel injury is rated using chapter 16 the American Medical Association Guides to the Evaluation of Permanent Impairment, Fifth Edition. The rating is based on lack of sensation and the amount of strength in the median nerve.
In this article, our California personal injury attorneys will explain:
- 1. What is carpal tunnel syndrome?
- 2. What causes carpal tunnel syndrome?
- 3. How is carpal tunnel syndrome diagnosed?
- 4. What is the treatment for a carpal tunnel injury?
- 5. Filing a claim for a carpal tunnel injury
- 6. How a carpal tunnel injury is rated for disability level
- 7. Pursuing a carpal tunnel claim in California workers’ compensation
Carpal tunnel syndrome (CTS) is likely the most frequently repetitive motion injury in California workers’ compensation.1 It occurs when the median nerve, which runs from the forearm to the palm, is irritated at the wrist.2
It can result in numbness, weakness, and pain in the hand and wrist.3 Symptoms usually start gradually with frequent burning, tingling, itching, or numbness in the palm of the hand and the fingers, especially the thumb, index, and middle fingers.4
Example: Ken is a computer programmer. He uses a keyboard and mouse all day. He first develops tingling in the thumb and index finger of his right hand. He then begins to have numbness and pain in both hands.
The pain is less when Ken is not working for a few days and becomes more severe after working all day. He is also losing grip strength.
Although a medical evaluation is required, it is very likely that Ken has CTS in both wrists.
There is no clear cause of CTS. Repeated motion of the wrist can cause swelling of the median nerve. This can come from:
- hand positioning while using a keyboard or mouse
- vibration from power tools
- any other repeated movement of the wrists5
As CTS occurs over a period of time, a carpal tunnel injury will likely be a cumulative trauma.
A cumulative trauma is an injury that happens from repeated activities over more than one day.
Up to 20% of the population that do hand-intensive activities five days a week for at least five hours a day will develop CTS or similar condition.6
Women are three times as likely to develop CTS as men. This may be because women on average have a narrower carpal tunnel for the median nerve to travel through, therefore, making it is more likely to become compressed.7
Common occupations that may be more prone to CTS include:
- assembly line work
- keyboarding occupations
- construction work8
In California workers’ compensation, CTS has been diagnosed in many occupations. Those occupations include:
- truck driver9
- office assistant11
- grocery clerk13
- automotive line worker14
- police officer15
Any worker in any occupation with extensive hand use can be susceptible to CTS and pursue a workers’ compensation claim.
Example: Dave is a carpenter in the film industry. He uses a hammer, electric drill, saw, and sander during the course of his job. He has been experiencing increasing numbness and tingling in his fingers. Some days he drops tools due to loss of grip strength.
Based on Dave’s job duties and symptoms, there is a strong possibility he has CTS.
Dave reports his injury to his employer. He is given a claim form and sent to a doctor.
CTS is diagnosed through:
- physical exam of the wrist and fingers for tenderness, swelling, sensation, or discoloration
- lab test to detect diabetes
- x-rays to detect arthritis
- manipulation of the wrist by the doctor to see if numbness or tingling occurs
- nerve conduction study that measures the electrical activity of the nerves and muscles
- ultrasound imaging that shows an abnormal size of the median nerve17
Example: Steve is having numbness and pain in his hands. He tells his doctor that he does soldering of computer components all day. He has pain and numbness in his fingers. His doctor does several tests in the office.
First, the doctor presses on the median nerve in Steve’s wrist. Steve has tingling in his fingers. The doctor then has Steve press the backs of his hands together. Steve again has numbness and tingling in his fingers.
Both tests are positive for CTS.
Steve’s doctor decides not to do any other testing because the testing is clear.
The California workers’ compensation system follows the American College of Occupational and Environmental Medicine‘s Hand, Wrist, and Forearm Disorder Guideline for treatment of CTS.
Treatment of CTS includes:
- over the counter pain relievers
- prescription corticosteroids
- avoiding activities that may provoke symptoms
- alternative therapies such as yoga18
There are times when CTS will require surgery, a procedure called a carpal tunnel release.
In the surgery, a ligament around the median nerve is severed to reduce pressure on the median nerve.19
After the surgery an injured worker may need 3-8 physical therapy visits over 3-5 weeks. The total recovery time is three months.20
An injured worker with CTS should be evaluated by an upper extremity specialist.21 This is an orthopedic doctor that specializes in hand and upper extremity injuries.
Example: Jennifer has attempted splinting her wrists and taking medication to treat her CTS. These treatments have not proven effective.
Even without working, Jennifer still has to use her hands in daily activities, and her condition has not improved.
She has carpal tunnel release surgery on an outpatient basis on her left wrist and seven weeks later, she has the same procedure on her right wrist. She has physical therapy and wears a brace after both surgeries. She is given pain medication. Jennifer has problems with grip strength that slowly improves.
To file a claim for workers’ compensation benefits for CTS requires filling out a claim form.22
Subsequent filing a claim, an injured worker often has to be placed on modified or light duty, as he or she cannot continue to with regular work consisting of hand-intensive activities.
The California workers’ compensation system uses the American Medical Association Guides to the Evaluation of Permanent Impairment, Fifth Edition (AMA Guides).23
CTS is evaluated in chapter 16 of the AMA Guides. The evaluation measures the loss of sensation that goes through the median nerve to the hand and fingers and loss of hand movement and strength. Testing for this is determined using a nerve conduction study.
The AMA Guides do not recommend that grip strength be used to rate CTS.24
Example: David has a medical evaluation for his CTS. The doctor sends David for a nerve conduction study. After the doctor receives the nerve conduction study results, she writes a report that finds David’s condition to be permanent and stationary, meaning it’s unlikely to improve, as of the date of the exam.
She gives him 5% impairment for both wrists based on the AMA Guides using the median nerve findings in the nerve conduction study.
The exact cause of CTS is unknown. It is up to the injured worker to explain the work activities that he or she believes led to the wrist and hand complaints.
It is also up to the injured worker to select a specialist in upper extremity injuries so that the right treatment is provided.
If an injured worker does not completely recover from a carpal tunnel injury, an understanding of the AMA Guides is necessary to obtain a full value for the permanent effects of his or her carpal tunnel injury.
Call us for help…
For help with filing a workers compensation claim in California, completing workers comp forms or appealing a denial of benefits, contact us. Our firm helps police officers, firefighters and other workers to get compensation for their job-related injuries in California.
- 1-9 Lawyer’s Guide to AMA Guides and CA Workers’ Comp § 9.06.
- 1-9 Lawyer’s Guide to AMA Guides and CA Workers’ Comp § 9.06.
- Pfundstein v. Hendrickson Trucking 2016 Cal. Wrk. Comp. P.D. LEXIS 403.
- Rivera v. Costco, 2011 Cal. Wrk. Comp. P.D. LEXIS 296.
- McGee v. State of California, 2012 Cal. Wrk. Comp. P.D. LEXIS 522.
- Mackin v. WCAB (2014) 79 Cal. Comp. Cases 1563.
- Gelson’s v. WCAB (003) 68 Cal. Comp. Cases 1772.
- Toyota Motor v. WCAB (2002) 67 Cal. Comp. Cases 60.
- Mckenna v. City of San Carlos Police Department, 2010 Cal. Wrk. Comp. P.D. LEXIS 487.
- Hager v. County of Santa Clara Central Fire District, 2015 Cal. Wrk. Comp. P.D. LEXIS 254.
- Cal. Code Regs., tit 8, § 9792.24.3.
- Shaffer v. WCAB, 2005 Cal. Wrk. Comp. P.D. LEXIS 14.
- Cal. Lab. Code § 4660.1.
- Andersson et al., AMA Guides to the Evaluation of Permanent Impairment, 5th Edition (2000)