title: Ultrasound-guided perineural injection for nerve blockade: Does a single-sided injection produce circumferential nerve coverage?
abstract: OBJECTIVE
  Our current clinical technique for sonographic-guided perineural injection consists of two-sided perineural needle placement to obtain circumferential distribution of the injectate. This study aimed to determine if a single-side needle position will produce circumferential nerve coverage.
  
  
  METHODS
  Fresh-frozen cadaveric specimens were used for this study. In six upper extremities, a needle was positioned along the deep surface of median, radial, and ulnar nerves in the carpal tunnel, radial tunnel, and cubital tunnel, respectively, and 2 ml of contrast was injected for each nerve. In three pelvic specimens, a needle was positioned deep to the sciatic nerves bilaterally, and 5 ml of contrast was injected. An additional four median nerve injections were performed using superficial surface needle position. The specimens then underwent CT scanning to assess the distribution of the perineural contrast medium.
  
  
  RESULTS
  One hundred percent of the radial, ulnar, and sciatic nerves demonstrated circumferential distribution on CT. Only 50% of the median nerve injections with the needle placed deep to the nerve produced circumferential coverage, whereas 100% of median nerves injected with the needle between the nerve and retinaculum demonstrated circumferential coverage. The average length of spread of perineural injectate was 11.6 cm in the upper extremity and 10.3 cm for the sciatic nerves.
  
  
  CONCLUSIONS
  Using clinical volumes of fluid, needle positioning at the deep surface of upper extremity and sciatic nerves was sufficient to produce circumferential coating of the nerve, except in the carpal tunnel, where placement of the needle between the nerve and flexor retinaculum is recommended. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:465-469, 2016.
authors.affiliation: Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York. oknwawka@gmail.com.|Weill Cornell Medical College of Cornell University, New York, New York. oknwawka@gmail.com.
authors.forename: O Kenechi
authors.initials: OK
authors.lastname: Nwawka
authors.affiliation: Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York.|Weill Cornell Medical College of Cornell University, New York, New York.
authors.forename: Theodore T
authors.initials: TT
authors.lastname: Miller
authors.affiliation: Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York.|Weill Cornell Medical College of Cornell University, New York, New York.
authors.forename: Shari T
authors.initials: ST
authors.lastname: Jawetz
authors.affiliation: Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York.|Weill Cornell Medical College of Cornell University, New York, New York.
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Saboeiro
mesh_terms: D002102:Cadaver; D003287:Contrast Media / Q000008:administration & dosage* / Q000493:pharmacokinetics; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008475:Median Nerve / Q000000981:diagnostic imaging*; D009407:Nerve Block; D010525:Peripheral Nerves / Q000000981:diagnostic imaging*; D011826:Radial Nerve / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D014459:Ulnar Nerve / Q000000981:diagnostic imaging*; D018084:Ultrasonography, Interventional; D034941:Upper Extremity / Q000000981:diagnostic imaging / Q000294:innervation
chemical_list: D003287:Contrast Media
keywords: interventional ultrasound; local anesthesia; peripheral nerves; sciatic nerve; upper extremity