title: Comparison of a GPS needle-tracking system, multiplanar imaging and 2D imaging for real-time ultrasound-guided epidural anaesthesia: A randomized, comparative, observer-blinded study on phantoms.
abstract: BACKGROUND
  The real-time ultrasound-guided paramedian sagittal oblique approach for neuraxial blockade is technically demanding. Innovative technologies have been developed to improve nerve identification and the accuracy of needle placement. The aim of this study was to evaluate three types of ultrasound scans during ultrasound-guided epidural lumbar punctures in a spine phantom.
  
  
  METHODS
  Eleven sets of 20 ultrasound-guided epidural punctures were performed with 2D, GPS, and multiplanar ultrasound machines (660 punctures) on a spine phantom using an in-plane approach. For all punctures, execution time, number of attempts, bone contacts, and needle redirections were noted by an independent physician. Operator comfort and visibility of the needle (tip and shaft) were measured using a numerical scale.
  
  
  RESULTS
  The use of GPS significantly decreased the number of punctures, needle repositionings, and bone contacts. Comfort of the physician was also significantly improved with the GPS system compared with the 2D and multiplanar systems. With the multiplanar system, the procedure was not facilitated and execution time was longer compared with 2D imaging after Bonferroni correction but interaction between the type of ultrasound system and mean execution time was not significant in a linear mixed model. There were no significant differences regarding needle tip and shaft visibility between the systems.
  
  
  CONCLUSIONS
  Multiplanar and GPS needle-tracking systems do not reduce execution time compared with 2D imaging using a real-time ultrasound-guided paramedian sagittal oblique approach in spine phantoms. The GPS needle-tracking system can improve performance in terms of operator comfort, the number of attempts, needle redirections and bone contacts.
authors.affiliation: Department of anesthesiology and critical care medicine, Inserm unit 1046, Montpellier university hospital, university Montpellier 1, Montpellier, France.
authors.forename: Cécilia
authors.initials: C
authors.lastname: Menacé
authors.affiliation: Department of anesthesiology and critical care medicine, Inserm unit 1046, Montpellier university hospital, university Montpellier 1, Montpellier, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Choquet
authors.affiliation: Department of anesthesiology and critical care medicine, Inserm unit 1046, Montpellier university hospital, university Montpellier 1, Montpellier, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Abbal
authors.affiliation: Department of anesthesiology and critical care medicine, Inserm unit 1046, Montpellier university hospital, university Montpellier 1, Montpellier, France; Department of medical statistics, Montpellier university hospital, 34295 Montpellier, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Bringuier
authors.affiliation: Department of anesthesiology and critical care medicine, Inserm unit 1046, Montpellier university hospital, university Montpellier 1, Montpellier, France. Electronic address: x-capdevila@chu-montpellier.fr.
authors.forename: Xavier
authors.initials: X
authors.lastname: Capdevila
mesh_terms: D000328:Adult; D000767:Anesthesia, Epidural / Q000379:methods*; D004824:Epidural Space / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015233:Models, Statistical; D009339:Needles; D019047:Phantoms, Imaging; D016037:Single-Blind Method; D013129:Spinal Puncture / Q000379:methods; D013131:Spine / Q000000981:diagnostic imaging; D018084:Ultrasonography, Interventional / Q000379:methods*
keywords: Electromagnetic tracking systems; Epidural; Phantom; Three/four-dimensional ultrasound imaging; Ultrasound-guided puncture