Though often associated with repetitive stress injury, Carpal Tunnel Syndrome (CTS) can be caused motor vehicle collision or other trauma. Diagnosis of CTS as a result of trauma may be difficult due to a doctor’s misperception that a patient’s CTS only comes from repetitive stress, delayed onset of symptoms, or overlapping injuries.
The carpal tunnel is formed by a semi-circle of bones in the wrist on three sides and the transverse carpal ligament on the fourth. The tunnel is a defined space without the capacity to enlarge. The median nerve, nine tendons and spongy tissue around the tendons, called tenosynovium, pass through the carpal tunnel. When inflammation of the tissues from an acute trauma or a chronic long term repetitive stress occurs within this limited space, the median nerve is compressed, causing symptoms into the fingers and hand.
Symptoms of CTS may include intermittent or constant numbness in the affected hand(s). Patients may report numbness in the whole hand, despite the fact that the median nerve affects only the thumb, index and middle fingers. Patients may report burning or tingling sensations. Symptoms may be activity-dependent, occurring at night, while driving, typing, holding a book or other tasks involving use of the wrist. There may be decreased grip strength resulting in difficulty forming a fist, grasping small items or performing other manual tasks.
CTS is caused by chronic compression of the median nerve, as opposed to an acute injury to the median nerve itself.[1] This may explain the frequent delayed onset of symptoms following trauma. In a 1981 study, 6 out of 7 patients did not develop symptoms of CTS for 2 weeks to several months following the trauma. All patients were driving and holding the steering wheel during the collision. Coert, et al., found that as many as 22% of injured motor vehicle collision victims develop CTS.[2]
This delayed onset of symptoms from the time of the trauma and when reporting it to a doctor often results in the health provider concluding that CTS symptoms are related to repetitive stress conditions rather than the trauma. A thorough history, including the lack of pre-trauma wrist symptoms, proper understanding the mechanism of injury (hands on the steering wheel or not, hands slammed into a dashboard when bracing) is vital to proper diagnosis and determining the cause.
Diagnosis of CTS can be further complicated by multiple potential causes of hand symptoms following trauma. Motor vehicle collisions often result in cervical spine injuries, which is a frequent source of upper extremity symptoms. There may also be compression at the elbow or thoracic outlet. These injuries are not all mutually exclusive and symptoms could be caused by multiple injuries or areas of compression along the nerve.[3]
Treatment for CTS may include a wide range of adaptations and treatments. Regardless of the cause, repetitive stress can exacerbate a CTS condition. Ergonomic workplace assessment and modifications may be of benefit. Treatment options may include chiropractic manipulation, physical therapy, splinting, non-steroidal anti-inflammatories and/or surgery. Failure to address traumatically-induced CTS could result in permanent nerve injury.
A patient with traumatically-induced CTS as a result of another’s negligence may benefit from a consultation with attorneys familiar with the law and the medicine behind traumatic injury. An experienced attorney can develop a thorough history to rule out pre-existing conditions and address issues of causation likely to be used by the insurance companies involved.
