Extraneural findings during peripheral nerve ultrasound: Prevalence and further assessment

Introduction: In this study we evaluated the frequency and further assessment of extraneural findings encountered during peripheral nerve ultrasound (US). Methods: Our retrospective review identified 278 peripheral nerve US examinations of 229 patients performed between December 2014 and December 2015. Reports were reviewed to assess the number of studies without peripheral nerve abnormalities and the frequency and further assessment of extraneural findings. Results: A total of 107 peripheral nerve US examinations of 90 patients (49 men and 41 women, mean age 55 ± 16 years) did not report peripheral nerve abnormalities. Extraneural findings were observed in 24 of 107 (22.4%) studies. Fifteen of the 278 [5.4% (95% confidence interval 2.7%–8.1%)] studies led to a recommendation for additional imaging or clinical evaluation of an extraneural finding. Discussion: At least 5.4% (15 of 278) of peripheral nerve US studies led to additional clinical or imaging assessment.