title: Spinal needle navigation by tracked ultrasound snapshots.
abstract: OBJECTIVE
  Ultrasound (US) guidance in facet joint injections has been reported previously as an alternative to imaging modalities with ionizing radiation. However, this technique has not been adopted in the clinical routine, due to difficulties in the visualization of the target joint in US and simultaneous manipulation of the needle.
  
  
  METHODS
  We propose a technique to increase targeting accuracy and efficiency in facet joint injections. This is achieved by electromagnetically tracking the positions of the US transducer and the needle, and recording tracked US snapshots (TUSS). The needle is navigated using the acquired US snapshots.
  
  
  RESULTS
  In cadaveric lamb model, the success rate of facet joint injections by five orthopedic surgery residents significantly increased from 44.4% with freehand US guidance to 93.3% with TUSS guidance. Needle insertion time significantly decreased from 47.9 ± 34.2 s to 36.1 ± 28.7 s (mean ± SD). In a synthetic human spine model, a success rate of 96.7% was achieved with TUSS. The targeting accuracy of the presented system in a gel phantom was 1.03 ± 0.48 mm (mean ± SD).
  
  
  CONCLUSIONS
  Needle guidance with TUSS improves the success rate and time efficiency in spinal facet joint injections. This technique readily translates also to other spinal needle placement applications.
authors.affiliation: School of Computing, Queen’s University, Kingston, ON, Canada. ungi@cs.queensu.ca
authors.forename: Tamas
authors.initials: T
authors.lastname: Ungi
authors.forename: Purang
authors.initials: P
authors.lastname: Abolmaesumi
authors.forename: Rayhan
authors.initials: R
authors.lastname: Jalal
authors.forename: Mattea
authors.initials: M
authors.lastname: Welch
authors.forename: Irene
authors.initials: I
authors.lastname: Ayukawa
authors.forename: Simrin
authors.initials: S
authors.lastname: Nagpal
authors.forename: Andras
authors.initials: A
authors.lastname: Lasso
authors.forename: Melanie
authors.initials: M
authors.lastname: Jaeger
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Borschneck
authors.forename: Gabor
authors.initials: G
authors.lastname: Fichtinger
authors.forename: Parvin
authors.initials: P
authors.lastname: Mousavi
mesh_terms: D000818:Animals; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007278:Injections, Spinal / Q000379:methods*; D009339:Needles; D019047:Phantoms, Imaging; D012756:Sheep; D013131:Spine / Q000000981:diagnostic imaging* / Q000601:surgery; D025321:Surgery, Computer-Assisted / Q000379:methods*; D018084:Ultrasonography, Interventional / Q000379:methods*