Clinical diagnosis of carpal tunnel syndrome: old tests-new concepts

Abstract

Background: The diagnosis of carpal tunnel syndrome (CTS) continues to be neurophysiologically and clinically controversial. Earlier data concluding that the higher prevalence of persons with symptoms suggestive of CTS but without evidence of median mononeuropathy highlights the need for a better understanding of the underlying pathophysiology and natural history of CTS to provide a less empirical foundation for diagnosis and clinical management.

Objective: To examine the relationship between the clinical manifestations of CTS with the outcome of the diagnostic tools (nerve conduction tests and ultrasonography), and its implication for clinical practice.

Methods: Two-hundred and thirty-two patients (69 male and 163 female, ages ranging between 20 and 91 years) with CTS manifestations and 182 controls were included in this study. Diagnosis of CTS was based on the American Academy of Neurology clinical diagnostic criteria. All patients and controls completed a patient oriented questionnaire, were subjected to clinical testing for provocative tests for carpal tunnel syndrome (Tinel's, Phalen's, Reverse Phalen's and carpal tunnel compression tests), blood check for secondary causes of carpal tunnel syndrome, nerve conduction testing as well ultrasonographic assessment of the carpal tunnel and median nerve.

Results: One-hundred and seventy-seven out of 232 (76.3%) had abnormal nerve conduction studies. Forearm symptoms and tenosynovitis confirmed by US examination were found in 51.3% of cases. No significant difference was found on comparing anthropometric measures in the affected hands to the control group hands. A higher prevalence of positive Phalen's and CT compression were found in patients suffering from tenosynovitis regardless of their nerve conduction study results. Sensitivity of Tinel's, Phalen's, Reverse Phalen's and carpal tunnel compression tests was higher for the diagnosis of tenosynovitis than for the diagnosis of CTS (Tinel, 46% vs. 30%; Phalen's, 92% vs. 47%; Reverse Phalen's, 75% vs. 42%; carpal tunnel compression test, 95% vs. 46%). Similarly, higher specificity of these tests was found with tenosynovitis than CTS.

Conclusion: The results of this study revealed that Tinel's, Phalen's, Reverse Phalen's and carpal tunnel compression tests are more sensitive, as well as being specific tests for the diagnosis of tenosynovitis of the flexor muscles of the hand, rather than being specific tests for carpal tunnel syndrome and can be used as an indicator for medical management of the condition.