Surgery – Instruments – Light application
Reexamination Certificate
1998-01-20
2001-03-13
Jaworski, Francis J. (Department: 3737)
Surgery
Instruments
Light application
C606S019000, C606S042000, C606S001000, C607S122000
Reexamination Certificate
active
06200311
ABSTRACT:
BACKGROUND
The number and variety of medical methods available to treat cardiovascular disease has increased rapidly in recent years. More particularly, alternatives to open heart surgery and cardiovascular by-pass surgery have been extensively investigated, resulting in less invasive procedures such as percutaneous transluminal coronary angioplasty, laser angioplasty, and atherectomy. These procedures are primarily directed toward the reduction of stenoses within the vasculature of a patient by either expanding the lumen through the use of a balloon, or otherwise removing the material making up the stenosis.
While these procedures have shown considerable promise, many patients still require by-pass surgery due to the presence of extremely diffuse stenotic lesions, the presence of total occlusions and the presence of stenotic lesions in extremely tortuous vessels. Also, some patients are too infirm to successfully undergo the rigors of by-pass surgery, and because the above treatments may require surgical intervention if complications develop, these patients are untreatable.
One alternative to these procedures is known as transmyocardial revascularization (TMR). In TMR, channels are formed in the ventricle wall with a laser or other type of ablation device. These channels provide blood flow to ischemic heart muscle. A history and description of this method is presented by Dr. M. Mirhoseini and M. Cayton in “Lasers in Cardiothoracic Surgery” in
Lasers In General Surgery
(Williams and Wilkins; 1989 (pp. 216-223).
In the procedure described therein, after surgically opening the patient's chest to expose the heart, a carbon dioxide laser is used via an articulated arm delivery device to produce channels in the ventricle from the epicardium through to the myocardium. External pressure is used on the outside of the heart to stop bleeding from the ventricle through the newly created channel. Other early disclosures of this procedure are found in an article by Okada et al. in
Kobe J. Med. Sci
. 32, 151-161, October 1986 and U.S. Pat. No. 4,658,817 (Hardy). These early references describe intraoperative revascularization procedures which require an opening in the chest wall and include formation of the channels through the heart wall.
A proposed improvement in the design is described in Hardy—U.S. Pat. No. 4,658,817. A needle is added to the distal tip of the articulated arm system, with laser energy passing through the lumen of the needle. The metal tip of needle of the device is used to pierce the myocardium and the laser beam is used to create the desired channel through the remaining portion of the myocardium and through the adjacent endocardium. For a variety of reasons, the system of Hardy has not been used clinically to any significant extent. These prior procedures required the chest wall be opened in order to access the heart muscle with laser devices, which was highly invasive and resulted in severe complications.
A further improvement to the intraoperative TMR procedure is described in Aita—U.S. Pat. No. 5,554,152, issued Sep. 10, 1996, which is hereby incorporated by reference in its entirety wherein an elongated flexible lasing apparatus is inserted into the chest cavity of a patient and lasing channels are then formed in the heart wall. While the system of Aita has been found to be clinically quite successful, the system did not allow for easy access to the entire heart and was not always suitable for minimally invasive procedures through the chest wall.
What has been needed is a tissue ablation device with a probe that has the proper shape and configuration and sufficient maneuverability to access the desired areas of a patient's heart, particularly in minimally invasive procedures. The present invention satisfies these and other needs.
SUMMARY
The present invention is directed to an improved tissue ablation device which has an elongate probe with a proximal end and a distal end and which is configured to access desired regions of a patient's heart through port incisions, limited thoracotomy, or mini-sternotomy. The invention further comprises a handpiece which is attached to the proximal end of the elongate probe. The probe is rotatably attached to handpiece to allow rotation and manipulation within the patient's chest cavity while the handpiece held by the operator is outside the patient's chest. The handpiece may be ergonomically designed to fit within the hand of the operator to give the operator the grip and control on the elongate probe necessary to advance the probe through a small hole or trocar sheath in the patient's chest and reach the desired region of the patient's heart.
In one presently preferred embodiment, the handpiece is provided with an advancement mechanism which is mechanically coupled to the tissue ablation member at the distal end of the probe such that the advancement mechanism can be used to axially translate the tissue ablation member in relation to the elongate probe. The handpiece is also provided with an activation mechanism which is housed within the advancement mechanism and which controls activation of the tissue ablation member. In addition, the activation mechanism is coupled to the advancement mechanism in such a manner that the operator of the embodiment of the invention can simultaneously activate and advance the tissue ablation with one finger or thumb. This feature facilitates a coordination of movements and allows greater control over the manner in which tissue is removed from the patient's heart.
The embodiment of the activation mechanism also includes a cantilevered beam which is attached to the advancement mechanism and which is mechanically coupled to a button shaft. The free end of the beam is configured in a spaced relation to a plurality of electrical switches, such that depression of the button shaft translates the cantilevered beam so as to engage the electrical switches substantially simultaneously. The cantilevered beam is preferably configured to resist displacement as force is applied to it, until a threshold force is reached, at which point the cantilevered beam suddenly collapses with a resulting high acceleration of the free end of the cantilevered beam. The high acceleration of the beam upon collapse results in a high velocity at the time of engagement of the electrical switches, ensuring substantially simultaneous activation of the multiple electrical switches.
In a presently preferred embodiment, the invention includes an elongate probe which can be formed in a variety of shapes or curves, including, but not limited to, an “S” curve and a radiused curve, to facilitate access to various regions of a patient's heart. Improved access to the heart by the elongate probe can be further enhanced by the ability to change the shape of the elongate probe in vivo. Therefor, the distal section of the probe can further include a deflection mechanism which for a preferred embodiment has a flexible member with at least one lumen extending therethrough and a tensile member mechanically coupled to the distal end of the elongate probe offset from the longitudinal axis of the flexible distal end of the probe.
The handpiece further comprises a deflection actuator which includes means for pulling on the tensile member and thereby deflecting the distal end of the elongate probe. It may also be desirable for the operator of the device to fix the deflection of the distal end of the probe without the need to maintain force on the lever member. Therefor, the deflection actuator preferably includes a clutch which applies sufficient friction to the deflection actuator that it will maintain the deflected position of the distal end of the elongate probe unless force is applied to the deflection actuator by the operator of the device.
The deflection mechanism of the elongate probe may also include a resilience member disposed around the lumen or lumens of the flexible member such that kinking of the lumens of the distal end is prevented during deflection. The resilience member is preferably com
Baughman Tyler
Danek Christopher J.
Gertner Kevin
Taimisto Miriam H.
Uebelhoer Burt
Anderson William B.
Eclipse Surgical Technologies Inc.
Janofsky Ilene Lapidus
Jaworski Francis J.
Lynch Edward J.
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