Patent ID: 7158838
Filing Date: 2007-01-02
Classification: A61M,A61N

Abstract:
1. An introducer system for positioning and fixedly engaging a distal fixation helix of a lead at an implantation site within a patient's body, comprising: a torque transfer sheath, extending from a proximal end to a distal end, receiving the lead; an outer sheath, having a distal end, receiving the lead positioned within the torque transfer sheath; a handle operable between a first handle position enabling advancement and retraction of the lead through the handle and a second handle position fixedly engaging a proximal end of the lead within the handle, wherein the lead is advanced through the outer sheath to extend outward a predetermined distance from the distal end of the outer sheath and the fixation helix is rotated through the predetermined distance to be fixedly engaged at the implantation site in response to simultaneous rotation and advancement of the lead and the torque transfer sheath through rotation and advancement of the handle in the second handle position; a hub body, extending from a proximally extending portion having a threaded portion positioned thereon to a connecting portion, the outer sheath and the hub body being fixedly engaged through threaded interaction of mating threads formed between the outer sheath and the connecting portion of the hub body; a handle shaft having an axial bore extending through the length of the handle shaft from a proximal portion, to an intermediate portion, to a distal portion, the distal portion of the axial bore formed to receive the proximally extending portion of the hub body; a first engaging member positioned within the distal portion of the axial bore advancing through grooves formed by the threaded portion of the hub body to distally advance the handle shaft when the handle is in the second handle position as the handle shaft is rotated about the proximally extending portion; a second engaging member positioned within the proximal portion of the axial bore; and a cap that is advanced distally towards the handle shaft to engage the second engaging member against the lead in response to the handle being in the second handle position and is retracted proximally from the handle shaft to disengage the second engaging member from the lead in response to the handle being in the first handle position, wherein the proximal end of the torque transfer sheath is fixedly positioned within the proximal portion of the handle shaft and the rotation of the handle shaft about the proximally extending portion of the hub body when the handle is in the second handle position transmits torque through the torque transfer sheath to the lead to screw the fixation helix extending from the distal end of the outer sheath body into the implantation site, wherein the threaded portion includes a first portion having a first pitch and number of turns, a second portion having a second pitch and number of turns, and a third portion having a third pitch and number of turns, wherein the first portion, the second portion and the third portion correspond to torque transfer characteristics of the lead, wherein the first pitch and number of turns is selected to overcome windup of the lead within the outer sheath resisting transfer of rotational torque to the fixation helix, the second pitch and number of turns is selected to govern distal advancement of the fixation helix from the distal end of the outer sheath, and the third pitch and number of turns is selected to effect rotation of the fixation helix to engagte the fixation helix at the implantation site.