Patent Application
20050137575
The present invention relates generally to the field of medical devices and methods. In especially preferred forms, the present invention relates to minimally invasive devices and methods to permit localized injections of a therapeutic agent.
Cell transplantation to repopulate injured myocardium has shown to be an effective therapy for improving both systolic and diastolic ventricular function pre-clinically. Current cell delivery methods are either via an open surgical approach during coronary artery bypass or left ventricular assist device insertion or via a variation of endoventricular catheter delivery. Each of these conventional methods has benefits and limitations. For example, percutaneous catheter delivery of cells has the benefit of being minimally invasive but lacks direct visualization of the cell injection region. Open surgical delivery necessitates a sternotomy or thoracotomy but allows precise delivery of cells to the myocardium.
It would therefore be highly desirable if devices and/or methods could be provided which would allow the real time visual delivery of cells (or other therapeutic agents) to distinct organ locations in a minimally invasive manner. Such devices and/or methods could thereby obtain the benefits of precise therapeutic agent delivery under direct visualization. It is towards fulfilling such needs that the present invention is directed.
Broadly, the present invention is embodied in devices and methods whereby therapeutic agents may be injected into distinct organ locations in a minimally invasive manner. Most preferably the devices and methods of this invention employ a video-assisted thorascopic system (VATS) to enable a physician in real time to visually identify a distinct organ location into which therapeutic agent is to be injected.
In particularly preferred forms, the present invention is embodied in devices for injecting a therapeutic agent into a tissue site which include a proximal handle, and a tubular barrel distally extending from the handle. The barrel has an injection needle at a distal end thereof which is most preferably angled relative to the barrel's elongate axis. The internal space of the barrel is sized and configured to receive a cartridge containing a therapeutic agent to be injected into the tissue site. A plunger assembly and injection trigger assembly are provided so as to cause the plunger to expel a predetermined volume of the therapeutic agent from the cartridge to the needle and thereby allow injection thereof to the tissue site in response to operation of the trigger assembly.
A position dial may be provided so as to operably interconnect the barrel to the handle and to allow the barrel to be rotated about its longitudinal axis. Rotation of the position dial will therefore cause the barrel to rotate thereby allowing a selective change in the relative angular orientations of the injection needle.
In order to prevent inadvertent needle punctures while the device is being maneuvered, a needle guard is most preferably provided so as to sheath the needle. The needle guard is thus moveable between an advanced position wherein the injection needle is sheathed thereby, and a retracted position wherein the injection needle is exposed. Movements of the needle guard may be achieved by means of a pivotally moveable actuator lever attached to the patient external handle. An actuator rod operatively interconnects the actuator lever and the needle guard. As such, pivotal movements of actuator lever responsively moves the needle guard between its advanced and retracted positions.
These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.
Reference will hereinafter be made to the accompanying drawings, wherein like reference numerals throughout the various FIGURES denote like structural elements, and wherein;
One particularly preferred form of an injection device 10 is depicted in accompanying
The handle 12 and barrel 14 are joined to one another via a rotatable dial 18. More specifically, the rotatable dial 18 is coaxially fixed to the barrel 14 and is rotatable with respect to the handle 12. Thus, the barrel 14 and dial 18 may be rotated about the barrel's elongate axis (arrow Ar) as a unit so as to allow the physician to change the orientation of the angled injection needle 16 as may be desired to facilitate its placement and injection of the therapeutic agent. Most preferably, the dial 18 may be provided with position markings to assist the physician in determining the relative positioning of the distal needle 16.
A cartridge loading chamber 20 is provided in proximal axial section of the barrel 14. The loading chamber 20 thus allows a cartridge or vial 22 containing the therapeutic agent (e.g., cells) to be loaded into the hollow of the barrel 14 proximally of the needle 16. When positioned within the barrel 14, the discharge port 22-1 of the cartridge 22 will therefore be in communication with the injection needle 16 to allow the contents of the cartridge 22 to be transferred to and through the needle 16. A cover 24 attached to knob 26 allows the loading chamber 20 to be reciprocally slideably moved (arrow Ac) between an opened condition (as shown in solid line in
A tubular needle guard 28 is sleeved over a distal section of the barrel 14. As is perhaps better shown in
As shown in solid line in
A plunger 40 is provided at the distal-most end of a plunger control rod 42 mounted within the handle 12 for reciprocal rectilinear movements. The proximal-most end of the control rod 42 carries a knob 44. The control rod 42 also includes a longitudinal section of ratchet teeth 46 engageable with ratchet pawl 48. The knob 44 allows the control rod 42, and hence the distal plunger 40 thereof, to be pulled manually into a retracted position as shown in solid line in
Controlled advancement of the control rod 42, and hence the distal plunger 40 thereof, is achieved by operation of the engaged ratchet teeth 46 and pawl 48 by means of the injection trigger 50. As can be seen more clearly in
The forward distance which the plunger advanced each time the trigger 50 is depressed and released is determined by the geometries of the teeth 46 and pawl 48, as well as the dimensional “throw” of the pawl 48 (e.g., the number of adjacent teeth that are by-passed by the pawl when it disengages from a tooth and then re-engages with another one of the teeth proximally thereto). Most preferably, the pawl 48 is pivotally connected to a longitudinally slideable control member 58 which, in turn, is connected operatively to volume control dial 60. Thus, turning movement applied to the control dial 60 will translate into longitudinal movements distally or proximally (i.e., in dependence upon the direction of turning movement applied to the dial 60) of the control member 58. This longitudinal movement of control member 58 will thereby either increase or decrease the effective “throw” of the pawl 48 each time the trigger 50 is operated. Thus, by turning the control dial 60, the pawl 48 may be caused to engage either the immediately next successive one of the teeth 46, or every second, third, fourth etc. one of the teeth 46 each time the trigger 50 is operated. In such a manner, therefore, an attending physician may preselect the volume of therapeutic agent which is expelled from the needle 16 for each operable cycle of the trigger 50.
In use, the distal end of the barrel is inserted through a minimally invasive surgical incision near the organ to be injected. Thus, when injecting cells into myocardium, minimally invasive cardiac procedures may be employed which are well known to those in this art. The attending physician guides the distal end of the barrel 14 with the needle 16 sheathed by guard 28 under thorascopic visual observation using a patient external monitor and patient internal video probe (not shown) associated with a video-assisted thorascopic system (VATS). Once the site for injection has been determined the needle 16 may be unsheathed by retraction of the guard 28 and the relative angular orientation of the needle 16 changed as may be desired or necessary by manipulation of the dial 18. As shown in
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
