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To evaluate the clinical differences between patients with diabetes mellitus (DM) who have asymptomatic carpal tunnel syndrome (CTS) and those who have symptomatic CTS.
Sixty-three patients with DM were assessed using the Boston Carpal Tunnel Questionnaire (BCTQ), nerve conduction studies (NCS), and ultrasonographic evaluation of the cross-sectional area (CSA) of the median nerve. According to the BCTQ responses and NCS results, the patients were divided into the following three groups: group 1 (n=16), in which NCS results did not reveal CTS; group 2 (n=19), in which NCS results revealed CTS but the group scored 0 points on the BCTQ (asymptomatic); and group 3 (n=28), in which NCS results revealed CTS and the group scored >1 point on the BCTQ (symptomatic). The clinical findings, NCS results, and CSA of the median nerve were compared among the three groups.
There were no significant differences in age, DM duration, glycated hemoglobin levels, and presence of diabetic polyneuropathy among the three groups. The peak latency of the median sensory nerve action potential was significantly shorter in group 1 than in groups 2 and 3 (p<0.001); however, no difference was observed between groups 2 and 3. CSA of the median nerve at the carpal tunnel in group 2 was significantly larger than that in group 1 and smaller than that in group 3 (p<0.05).
The results of our study suggest that the symptoms of CTS in patients with diabetes are related to CSA of the median nerve, which is consistent with swelling of the nerve.
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To determine an ideal stimulation site of the medial antebrachial cutaneous nerve (MACN) using ultrasound measurement and to compare the efficiency of the new stimulation site with the conventional stimulation site on the nerve conduction study.
Both arms of 15 healthy participants were measured using ultrasound. The MACN was identified in the transverse view at each 0, 2, 4, 6, and 8 cm proximal sites from the medial epicondyle, and the distances to the median nerve and to the skin from the MACN were measured. The ideal stimulation site should be located at the level which can give the shortest distance from the skin and the longest distance from the median nerve in terms of volume conduction. To confirm the efficiency of the ideal site, we measured the amplitude of the MACN conduction study at the ideal site against one at the 4 cm proximal to the medial epicondyle (conventional site).
The ultrasound showed the ideal stimulation site for the MACN could be the elbow crease line. However, the nerve conduction study revealed that the amplitudes of the MACN were significantly larger at the 4 cm proximal to the medial epicondyle compared with ones at the ideal site.
The ideal stimulation site based on the ultrasound did not permit better stimulation site for the nerve conduction study of the MACN compared with the conventional site. Careful adjustment of the stimulation site on the basis of this study would contribute to an accurate conduction study of the MACN.
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To describe an ultrasonography-guided technique for cubital tunnel injection.
The ulnar nerves from 12 elbows of 6 adult cadavers were scanned, and the cross-sectional areas of the ulnar nerves, cubital tunnel inlets and outlets were measured by using ultrasonography. All elbows were dissected after an ultrasonography-guided dye injection at the inlet of the cubital tunnel. The dissectors evaluated the spread of dye and the coloration of the nerve and remeasured the cross-sectional areas of the cubital tunnel inlets and outlets.
After a real-time visualization of an ultrasonography-guided injection, the ulnar nerves were seperated from the medial groove for the ulnar nerve. All the ulnar nerves of the cadavers were successfully colored with the dye, from the inlet to oulet of the cubital tunnel. The post-injection cross-sectional areas were significantly larger than the pre-injection cross-sectional areas. No significant differences were detected in the post-injection cross-sectional areas of the cubital tunnel outlet and the ulnar nerve as compared with the pre-injection areas.
Clinicians should consider real-time visualization of ultrasonography for guided injection around the ulnar nerve at the inlet of the cubital tunnel.
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