title: Free-handling technique or mechanical needle guide device?
authors.forename: Harald C
authors.initials: HC
authors.lastname: Rettig
authors.forename: Mathieu J M
authors.initials: MJ
authors.lastname: Gielen
mesh_terms: D004867:Equipment Design; D006801:Humans; D009339:Needles; D009407:Nerve Block / Q000295:instrumentation / Q000379:methods; D018084:Ultrasonography, Interventional / Q000379:methods*