title: The arcTOA Technique for Out-of-Plane Ultrasound-Guided Injections.
abstract: Out-of-plane (OOP) ultrasound-guided injections are often cited as being more difficult than in-plane ultrasound-guided injections, particularly for the novice ultrasonographer. In certain circumstances, the OOP approach is required as a result of the constraints of adjacent anatomic structures. To date, only the "walk-down" approach has been detailed in the literature as a means of improving accuracy with the OOP approach. However, this approach uses a set needle entry angle (angle of incidence) and distance for the injection. This article uses the trigonometric function, arctan = opposite/adjacent (arcTOA), to allow readers to easily estimate the needle angle of incidence (arcTOA technique), allowing more flexibility when planning and performing OOP injections.
authors.affiliation: Department of Orthopaedics and Rehabilitation, University of Iowa Sports Medicine, 2701 Prairie Meadow Dr, Iowa City, IA 52242(∗). Electronic address: sathish.k.rajasekaran@gmail.com.
authors.forename: Sathish
authors.initials: S
authors.lastname: Rajasekaran
authors.affiliation: Department of Physical Medicine and Rehabilitation, Mayo Clinic School of Medicine, Rochester, MN; Department of Physical Medicine and Rehabilitation, University of California Davis School of Medicine, Sacramento, CA(†).
authors.forename: Jonathan T
authors.initials: JT
authors.lastname: Finnoff
mesh_terms: D006801:Humans; D007267:Injections; D009339:Needles; D018084:Ultrasonography, Interventional