title: Nerve ultrasound identifies abnormalities in the posterior interosseous nerve in patients with proximal radial neuropathies.
abstract: BACKGROUND
  The radial nerve and posterior interosseous nerve (PIN) are prone to injury at multiple sites. Electrodiagnostic (EDx) studies may only identify the most proximal lesion. Nerve ultrasound could augment EDx by visualizing additional pathology.
  
  
  METHODS
  This investigation was a retrospective examination of ultrasound and EDx from 26 patients evaluated for posterior cord/radial/PIN lesions.
  
  
  RESULTS
  Eighteen of 26 patients had abnormalities on EDx (15 radial, 2 PIN, 1 posterior cord). Ultrasound identified 15 of 18 (83%) of the EDx abnormalities and provided additional diagnostic information. In 6 of 15 (40%) patients with EDx evidence of radial neuropathy, ultrasound identified both radial nerve enlargement and additional, unsuspected PIN enlargement (53% to 339% enlarged vs. unaffected side). Ultrasound also identified: nerve (dis)continuity at the trauma site (n = 8); and nerve tumor (n = 2; 1 with normal EDx).
  
  
  CONCLUSIONS
  In radial neuropathy, ultrasound often augments EDx studies and identifies a second lesion in the PIN. Further studies are required to determine the etiology and significance of this additional distal pathology.
authors.affiliation: Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St. Louis, Missouri, 63110, USA.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Dietz
authors.affiliation: Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St. Louis, Missouri, 63110, USA.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Bucelli
authors.affiliation: Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St. Louis, Missouri, 63110, USA.
authors.forename: Alan
authors.initials: A
authors.lastname: Pestronk
authors.affiliation: Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St. Louis, Missouri, 63110, USA.
authors.forename: Craig M
authors.initials: CM
authors.lastname: Zaidman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004568:Electrodiagnosis; D005260:Female; D005542:Forearm / Q000000981:diagnostic imaging / Q000294:innervation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011826:Radial Nerve / Q000000981:diagnostic imaging* / Q000473:pathology; D020425:Radial Neuropathy / Q000175:diagnosis*; D012189:Retrospective Studies; D014463:Ultrasonography; D055815:Young Adult
keywords: double crush syndrome; neuropathy; posterior interosseous nerve; radial nerve; ultrasound