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, 14 (2), 155-162

Ultrasound Measurement of the Cross-Sectional Area of the Median Nerve: The Effect of Teaching on Measurement Accuracy

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Ultrasound Measurement of the Cross-Sectional Area of the Median Nerve: The Effect of Teaching on Measurement Accuracy

Jared A Crasto et al. Hand (N Y).

Abstract

Background: The purpose of this study was to determine the effect of concise instruction and guidance on the accuracy of measuring the cross-sectional area of the median nerve at the carpal tunnel inlet.

Methods: Seven orthopedic residents and 5 hand fellows obtained serial measurements of the median nerve at the carpal tunnel inlet using a 15-6 MHz ultrasound (US) probe. After a 5-minute teaching session, all participants repeated measurements. A single cadaveric specimen was used. Measurements were compared with the measurement of a fellowship-trained hand surgeon with extensive experience in US diagnosis of carpal tunnel syndrome. This was considered the reference standard.

Results: The rate of participants selecting the correct structure to measure on US was 36% before instruction and 97% after. Discarding the measurements of the incorrect structure, the average measurement was 4.8 mm2 before instruction and 5.2 mm2 after. The standard measurement was 6 mm2. The average deviation from the standard measurement -.2 mm2 before instruction and -0.8 mm2 after. The percent of measurements (of the correct structure) that fell within 1 mm2 of the standard measurement increased from 62% to 74%. Participant self-reported confidence in performing measurements elevated from 2.4/10 before instruction to 6.5/10 after.

Conclusions: US of the median nerve cross-sectional area can be efficiently taught and results in measurements consistent with that of an experienced operator.

Keywords: carpal tunnel syndrome; education; point-of-care; teaching; ultrasound.

Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

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