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Background: Nerve conduction study (NCS) is the only useful test for objective assessment of carpal tunnel syndrome (CTS). However, the relationship between pre- and postoperative NCS and clinical outcomes was unclear. This study aimed to determine whether pre- and postoperative (6 months) NCS could predict patient-oriented and motor outcomes (6 and 12 months postoperatively) in patients with CTS., Method: Of the 85 patients with CTS, 107 hands were analyzed from March 2011 to March 2020. All patients underwent open carpal tunnel release and were examined using the disabilities of the arm, shoulder and hand (DASH) questionnaire and grip strength (GS) preoperatively and 6 and 12 months postoperatively. Moreover, NCS was examined preoperatively and 6 months postoperatively. Distal motor latency (DML) and sensory conduction velocity (SCV) were the parameters used for NCS. The correlation coefficient between NCS and DASH or GS was calculated. A receiver operating characteristic curve was utilized to determine the NCS threshold value to predict DASH and GS improvement., Results: The average scores of GS preoperatively and 6 and 12 months postoperatively were 21.3, 22.3, and 22.8, respectively. On the other hand, the average scores of DASH preoperatively and 6 and 12 months postoperatively were 28.8, 18.3, and 12.2, respectively. The average NCS scores (DML and SCV) preoperatively/6 months postoperatively were 7.3/5.4 and 27.8/36.7, respectively. Preoperative NCS did not correlate with DASH and GS. Postoperative SCV correlated with the change in grip strength (6-12 months, r = 0.67; 0-12 months, r = 0.60) and DASH (0-12 months, r = 0.77). Moreover, postoperative DML correlated with the change in DASH (6-12 months, r = - 0.33; 0-12 months, r = - 0.59). The prediction for the improvement of GS/DASH achieved a sensitivity of 50.0%/66.7% and a specificity of 100%/100%, at an SCV cutoff score of 38.5/45.0 or above. The prediction for improvement of GS/DASH achieved a sensitivity of 83.3%/66.7% and a specificity of 100%/66.7% at a DML cutoff score of 4.4/4.4 or below., Conclusion: NCS at 6 months postoperatively can be used to predict the improvement of clinical outcome after 6 months postoperatively in patients with CTS., (© 2021. The Author(s).)

Background: A facile electromyographic test in the outpatient clinic is needed to evaluate the outcome of screening for carpal tunnel syndrome. The purpose of the current prospective study was to compare the accuracy of Nervepace digital electroneurometer (Nervepace) and Dantec Neuromatic 2000M (Dantec) measurements of a wide range of distal motor latency (DML) of the median nerve., Methods: The DML values for 112 of 126 median nerves examined with Nervepace and conventional electromyography, Dantec were statistically analyzed in this prospective study. The 30 hands of 15 clinically healthy adults 20-24 years old served as the reference group. Sixty consecutive patients (96 hands) with idiopathic carpal tunnel syndrome provided a wider range of DML values. All of the patients had standard clinical tests and standard motor (Dantec and Nervepace) and sensory (Dantec) electrodiagostic tests before endoscopic carpal tunnel release., Results: The DML was measurable in all 30 hands of the reference group, in all 96 hands of the patients by Dantec, but in only 82 hands (52 patients) by Nervepace. Nervepace and Dantec DML values of 6.0 ms or less had high correlation and agreement., Conclusions: Correlation and agreement decreased significantly among values greater than 6.0 ms.

Nerve conduction studies performed between 1994 and 1996 on the median nerves of 204 hands of 113 patients [20 patients in hemodialysis (HD) with diabetic nephropathy, 27 without diabetes mellitus in HD for 10 years or more, 18 without diabetes mellitus in HD for less than 10 years, and 48 with diabetes mellitus not undergoing HD] were reviewed retrospectively to develop a discriminating tool that would better inform treatment selection for patients with carpal tunnel syndrome (CTS) in HD. Scatter diagrams were drawn from the results of this study, and a regression formula was obtained. Among the long-term HD patients without diabetic nephropathy, distal motor latency (DML) tended to increase without a significant concomitant reduction in motor nerve conduction velocity (MCV) in the forearm. In contrast, in HD patients with diabetic nephropathy, DML tended to increase and MCV was significantly lower despite shorter HD periods. The study showed that in HD patients, in whom the MCV(m/s) > 11[9 - DML(ms)], the surgical results might be excellent or good. The formula was tested against the results of the 30 surgical cases. The sensitivity of this formula was 0.84, and the specificity was 1.00. The formula produced a predictor of surgical results when used in conjunction with other criteria for CTS in HD patients, especially those with diabetic nephropathy.

The grading system of Hashizume and Hirooka for carpal tunnel syndrome (CTS) was modified to refine the system for surgical treatment selection for specific subsets of CTS in patients with rheumatoid arthritis (RA). The grading system uses clinical signs and symptoms of CTS, including pain indications, to identify surgical subsets of patients to facilitate treatment selection. Retrospective analysis of the system included radiographic and electromyographic findings. Twenty-nine hands of 21 adult patients with CTS in RA were graded in the current study. Eight hands with mild synovitis received conservative treatment only. Endoscopic carpal tunnel release (ECTR), using Okutsu's universal subcutaneous endoscopic system with a clear cannula, was performed in 11 hands with moderate synovitis. Open carpal tunnel release (OCTR) combined with flexor tenosynovectomy was performed in 9 hands with severe synovitis. One more hand required OCTR after ECTR when malignant RA was diagnosed. Clinical results, evaluated using Kelly's criteria, were: excellent in 19 hands, good in 5, fair in 4, and poor in the 1 patient with malignant RA. Clinical symptoms of CTS improved in all but the latter patient. Although the sample size in the current study is small, the results appear to warrant further study to determine the clinical utility of the grading system.