Are the Sensory Fibers of the Ulnar Nerve Affected in Carpal Tunnel Syndrome?

Comparison of the modified method and the median sensory-ulnar motor latency difference in the diagnosis of carpal tunnel syndrome

OBJECTIVES

This study aimed to compare the modified method and the median sensory-ulnar motor latency difference in the diagnosis of carpal tunnel syndrome.

METHODS

The study recruited the electromyography results of 105 hands of 60 patients who had a complaint of carpal tunnel syndrome (CTS) on the hand diagram. The average sensory-ulnar motor delay difference (MSUMLD) was determined by simple subtraction, and the modified method was calculated based on the results of the classic method. The modified method and the MSUMLD were compared according to their sensitivity and specificity in the diagnosis of CTS.

RESULTS

In this study, 54 hands were evaluated with a unilateral nerve conduction study (45 right; 9 left). A total of 23 hands with CTS and 31 hands without CTS were diagnosed electrophysiologically. The MSUMLD had 91.3% sensitivity and 93.5% specificity; however, the modified method showed 95.7% sensitivity and 96.8% specificity in the diagnosis of CTS. Moreover, the modified method had 100% sensitivity and specificity in the diagnosis of moderate CTS.

CONCLUSIONS

The modified method may have higher diagnostic accuracy than the MSUMLD for diagnosing CTS.

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

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.

Evaluation of axonal loss in ulnar sensory nerve fibers recorded from ring and little fingers secondary to idiopathic carpal tunnel syndrome in Egyptian patients

Background

The association between carpal tunnel syndrome (CTS) and ulnar nerve entrapment is unclear, and the extra-median paresthesia in the ulnar nerve territory innervation in CTS is unexplained. Our purpose is to evaluate the neurophysiologic changes in ulnar nerve sensory fibers secondary to idiopathic CTS in comparison to normal subjects, and their relation to the severity of CTS.

Results

The difference between CTS and control hands regarding all parameters of ulnar motor nerve conduction studies (MNCS) was not statistically significant (p > 0.05). There was a statistically significant difference in all parameters of median sensory conduction study (SCS) and MNCS between CTS and control hands (p < 0.0001) except for conduction velocity and in all parameters of median and ulnar SCS recording digit 4 (D4) (p < 0.05). The mean value of abnormalities of ulnar SCS recording D4 and digit 5 (D5) was significantly higher in moderate and severe CTS hands (p < 0.05). There were significant negative correlations between median motor and sensory latency and ulnar sensory amplitude recording D4 and D5.

Conclusion

Ulnar sensory nerve abnormalities exist among CTS patients, which were more in moderate and severe grades. The drop in amplitude of ulnar nerve sensory response argues in favor of the possible impact of CTS on the ulnar nerve and did not indicate axonal deterioration of the ulnar nerve.