Interventional needle having an automatically capping stylet

Abstract

The tip of a stylet which is received in a needle cannula is automatically capped in a guard body when the stylet is withdrawn from the cannula. The stylet may be reassembled in the cannula and put into working position, with the point of the tip extending from the cannula shaft, by reinserting the stylet and guard into the cannula hub. The guard contains an arm which moves into blocking position with respect to the tip of the stylet when it is withdrawn from the cannula by following a cam surface on the cannula hub (either inside or outside the hub for different styles of needle cannulas). The arm may be spring biased, across a hole in the guard in which the stylet is slidably disposed into interfering relationship with the arm. The cam surface urges the arm to bring a portion thereof which protects the point of the tip of the stylet and captures it inside the guard. The arm and cam prevent removal of the stylet from the cannula until the tip is covered and protected by the guard, thereby automatically capping the tip of the stylet to prevent potentially dangerous, inadvertent, or accidental sticking of medical personnel. The interventional needle apparatus may be used as an angiographic needle and for other purposes, wherever access to vessels, kidneys or other body parts as for the insertion of catheters, infusions or drainage of body fluids including spinal fluid is required or where tissue is obtained by needle biopsy.