title: CT-guided cervical transforaminal steroid injections: where should the needle tip be located?
abstract: OBJECTIVE
  The aim of CT-guided CTSI is to inject medication into the foraminal region where the nerve root is inflamed. The optimal location for needle placement and therapeutic delivery, however, remain uncertain. The purpose of this study was to investigate how needle positioning and angle of approach impact the transforaminal distribution of injectate.
  
  
  METHODS
  We retrospectively reviewed fluoroscopic images from 90 CT-guided CTSI procedures for needle-tip location, needle angle, and contrast distribution. Needle-tip position was categorized as either foraminal zone, junctional, or extraforaminal. Distribution of contrast injected immediately before steroid administration was categorized as central epidural, intraforaminal, or extraforaminal in location. Needle-tip location and angle were correlated with contrast distribution.
  
  
  RESULTS
  The needle tip was most commonly placed in the junctional position (36 cases, 40%), followed by foraminal (30 cases, 33%) and extraforaminal (24 cases, 27%) locations. Intraforaminal contrast distribution was highest when the needle location was foraminal (30/30, 100%) or junctional (35/36, 97%), compared with extraforaminal (7/24, 29%) (P value <.0001). There was no relationship between needle angle and contrast distribution.
  
  
  CONCLUSIONS
  Needle-tip location at the outer edge of the neural foramen (junctional location) correlated well with intraforaminal distribution of contrast for CT-guided CTSI and compared favorably with injectate distribution following foraminal zone needle positioning. Junctional needle positioning may be preferred over the foraminal zone by some proceduralists. Extraforaminal needle positioning resulted in less favorable contrast distribution, which may significantly diminish the therapeutic efficacy of CTSI.
authors.affiliation: Department of Radiology, Division of Neuroradiology, Duke University Medical Center, Durham North Carolina 27710, USA. jennykh@gmail.com
authors.forename: J K
authors.initials: JK
authors.lastname: Hoang
authors.forename: D P
authors.initials: DP
authors.lastname: Massoglia
authors.forename: M A
authors.initials: MA
authors.lastname: Apostol
authors.forename: C D
authors.initials: CD
authors.lastname: Lascola
authors.forename: J D
authors.initials: JD
authors.lastname: Eastwood
authors.forename: P G
authors.initials: PG
authors.lastname: Kranz
mesh_terms: D000893:Anti-Inflammatory Agents / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007278:Injections, Spinal / Q000379:methods; D008297:Male; D008875:Middle Aged; D009339:Needles; D011843:Radiculopathy / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D015641:Radiography, Interventional / Q000379:methods*; D013126:Spinal Nerve Roots / Q000000981:diagnostic imaging / Q000187:drug effects; D013256:Steroids / Q000008:administration & dosage*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D000893:Anti-Inflammatory Agents; D013256:Steroids