• Jeffrey D Swenson and Nicholas A T Brown.
• University of Utah Orthopaedic Center, Department of Anesthesiology, University of Utah Medical Center, Salt Lake City, UT 84132, USA. jeff.swenson@hsc.utah.edu
• J Clin Anesth. 2007 May 1;19(3):175-9.

Study ObjectiveTo evaluate a new 20-gauge (G) fenestrated needle designed to be used with ultrasound guidance to deliver local anesthetic into the tissue plane of the fascia iliaca without immediate proximity to the femoral nerve.DesignProspective study.SettingUniversity hospital.Patients15 male volunteers.InterventionsTo determine the onset of motor and sensory block after ultrasound-guided injection of 1% lidocaine and iopamidol, fluoroscopy was performed during and after injection to discover the pattern of local anesthetic distribution. The buckling strength of the new needle was compared using a standard mechanical testing protocol to a conventional 22-G needle (Quincke type).Measurements And Main ResultsInjection through the fenestrated needle consistently produced sensory block in the anterior, medial, and lateral aspects of the thigh. All subjects were also observed to have loss of motor function in the quadriceps muscle. No subject experienced motor effect in the adductor muscles of the thigh. The fenestrated 20-G needle yielded at significantly larger compressive forces than did the standard 22-G needle (P < 0.001).ConclusionThe needle is novel in that it does not require immediate proximity to the femoral nerve or precise placement of the needle tip in the plane of the fascia iliaca. The 20-G fenestrated needle is stronger under compressive force than existing 22-G needles.

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