title: An ultrasonographic and histological study of intraneural injection and electrical stimulation in pigs.
abstract: BACKGROUND
  In this study we evaluated the minimum stimulating current associated with intraneural needle placement and sonographic appearance of intraneural injection.
  
  
  METHODS
  We inserted a needle 2 cm inside 28 pig nerves (brachial plexus in vivo), recorded the minimum current to elicit a motor response, and injected dye (5 mL) under ultrasound (US) imaging.
  
  
  RESULTS
  The minimum current to elicit a motor response was 0.43 mA (range: 0.12-1.8 mA). Nerve expansion was visualized by US in 24 of 28 nerves. Histology revealed penetration of the epineurium in these same 24 nerves. There was no evidence of dysplasia within the fascicle of any nerve.
  
  
  CONCLUSIONS
  US may prove useful to detect intraneural injection, whereas a motor response above 0.5 mA may not exclude intraneural needle placement. The correlation between intraneural injection and neurological dysfunction remains unclear.
authors: Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada. vincent.chan@uhn.on.ca
authors: Vincent W S
authors: VW
authors: Chan
authors: Richard
authors: R
authors: Brull
authors: Colin J L
authors: CJ
authors: McCartney
authors: Daquan
authors: D
authors: Xu
authors: Sherif
authors: S
authors: Abbas
authors: Patrick
authors: P
authors: Shannon
mesh_terms: D000818:Animals; D001917:Brachial Plexus / Q000166:cytology* / Q000000981:diagnostic imaging* / Q000502:physiology; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006652:Histological Techniques / Q000379:methods; D007267:Injections; D009339:Needles; D013552:Swine; D014463:Ultrasonography