Both idiopathic carpal tunnel syndrome (CTS) and Raynaud’s phenomenon (RP) are common, and may have similar clinical symptoms. The degree of their coexistence is uncertain. We have examined 30 patients, who were diagnosed clinically and electromyographically as having idiopathic CTS, for the presence of RP using a cold provocation test with photoplethysmography. The patients’ hands were exposed in water at 10°C for five minutes. A total of 18 patients (60%) was found to have RP; this is much greater than would be expected from the prevalence in the general population. Raynaud’s phenomenon should be considered when treating patients with CTS because of the possibility of coexistence and the similar symptoms of these two disorders

The diagnosis of nerve injury using thermotropic liquid crystal temperature strips was compared blindly and prospectively against operative findings in 36 patients requiring surgical exploration for unilateral upper limb lacerations with suspected nerve injury. Thermotropic liquid crystal strips were applied to affected and non-affected segments in both hands in all subjects. A pilot study showed that a simple unilateral laceration without nerve injury results in a cutaneous temperature difference between limbs, but not within each limb. Thus, for detection of a nerve injury, comparison was made against the unaffected nerve distribution in the same hand.

Receiver operating characteristic curve analysis showed that an absolute temperature difference ≥ 1.0°C was diagnostic of a nerve injury (area under the curve = 0.985, sensitivity = 100%, specificity = 93.8%).

Thermotropic liquid crystal strip assessment is a new, reliable and objective method for the diagnosis of traumatic peripheral nerve injuries. If implemented in the acute setting, it could improve the reliability of clinical assessment and reduce the number of negative surgical explorations.