Ring finger sensory latency difference in the diagnosis and treatment of carpal tunnel syndrome

Abstract

Objective To explore the sensitivity of median and ulnar nerve sensory latency differences in diagnosing carpal tunnel syndrome (CTS) at different severities. Methods CTS patients were divided into three groups based on disease severity (mild, moderate, and severe). Distal latency of sensory nerve action potential (SNAP) for the median and ulnar nerves was recorded. The sensitivity of SNAP distal latency to CTS and its correlation with CTS severity were analyzed. Results Significant differences were found in the median nerve sensory action potential distal latency (MSDL) and in the median and ulnar sensory latency difference to ring finger (MUD) but not in the ulnar nerve sensory action potential distal latency (USDL) between CTS and control. The sensitivity and specificity were 92.2 and 99.4% with an MSDL cutoff value of 2.40 ms, respectively, and were both 100% with a MUD cutoff value of 0.33 ms. There was no significant difference in USDL among the CTS and control groups. Significant differences were found in MSDL and MUD among the CTS severities and between mild and moderate CTS, but not between mild and severe CTS or between moderate and severe CTS. Correlations with CTS severity were observed for MSDL and MUD but not for USDL. Conclusion The ulnar nerve of the CTS patients was not damaged. A smaller MSDL reflected median nerve damage, which can be used for the early diagnosis of CTS. MUD correlated with CTS severity with a higher sensitivity than MSDL, which can provide therapeutic insight without pain to patients.

Occupational and non-occupational risk factors correlating with the severity of clinical manifestations of carpal tunnel syndrome and related work disability among workers who work with a computer

“…We also found a correlation between the sensory recordings on the ulnar nerve on the ring finger and CTS aggravation, disability, and risk factors, which supports other studies evidencing common moderate involvement of the ulnar nerve in the clinical presentations of CTS ( 132 , 133 , 134 , 135 , 136 , 137 , 138 ) or that computer work is associated with the ulnar nerve entrapment at the elbow (cubital tunnel syndrome) and the wrist (Guyon's canal syndrome) due to repetitive compression from leaning on the elbows or wrists during work with a mouse or a keyboard ( 139 , 140 , 141 ).…”

Evaluation of the Existing Electrophysiological Severity Classifications in Carpal Tunnel Syndrome

“…Median nerve conduction studies in CTS cases evaluate both sensory and motor nerve fibers. Electrophysiological severity classification in CTS is a useful method to show these evaluation parameters on a single scale [ 11 , 12 ], and there are many reports on clinical evaluations using severity classifications [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. However, as shown in this paper, the existing severity classifications do not always accurately reflect the severity of disease, and our results suggest the need to reevaluate previous studies that used these classifications.…”