title: Newborn brachial plexus palsy: evaluation of severity using quantitative ultrasound of muscle.
abstract: BACKGROUND
  We studied ultrasound features of muscle after nerve injury.
  
  
  METHODS
  We evaluated ultrasound measurements of muscle thickness and backscatter in injured and contralateral uninjured elbow flexors of 51 children with newborn brachial plexus palsy (NBPP) and compared the results to elbow flexor function (Active Movement Scale), defined as normal, moderate, or severe.
  
  
  RESULTS
  Compared with uninjured limbs, muscle in injured arms was 15% thinner with severe impairment, 17% thicker with moderate impairment, and no different with normal function. Relative to uninjured limbs, moderately impaired muscle was thicker than both severely impaired and normal strength muscle. Backscatter was higher in injured than in uninjured limbs regardless of function. In 17 patients with sequential measures, muscle thickness, but not backscatter, increased with function over time.
  
  
  CONCLUSIONS
  Muscle thickness differentiates moderate from severe impairment after NBPP and increases with recovery over time. Muscle backscatter identifies prior injury regardless of function.
authors.affiliation: Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St. Louis, Missouri 63110, USA. zaidmanc@neuro.wustl.edu
authors.forename: Craig M
authors.initials: CM
authors.lastname: Zaidman
authors.forename: Mark R
authors.initials: MR
authors.lastname: Holland
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Noetzel
authors.forename: Tae Sung
authors.initials: TS
authors.lastname: Park
authors.forename: Alan
authors.initials: A
authors.lastname: Pestronk
mesh_terms: D001917:Brachial Plexus / Q000000981:diagnostic imaging* / Q000503:physiopathology; D020516:Brachial Plexus Neuropathies / Q000151:congenital* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D004550:Elbow / Q000502:physiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016059:Range of Motion, Articular / Q000502:physiology; D012720:Severity of Illness Index; D014463:Ultrasonography