Ablation tool for forming lesions in body tissue

Details Ablation tool for forming lesions in body tissue Ablation tool for forming lesions in body tissue

1999-07-07

2001-09-18

Cohen, Lee (Department: 3739)

Surgery

Instruments

Electrical application

C607S099000, C607S105000, C607S113000, C607S119000, C604S114000

Reexamination Certificate

active

06290699

ABSTRACT:

TECHNICAL FIELD
The present description generally relates to medical tools and methods, and more particularly, an ablation tool and methods of use for forming lesions in body tissue.
BACKGROUND
Physicians employ tissue ablation to treat various medical conditions, including cardiac rhythm disfunction and benign prostatic hypertrophy. Tissue ablation is the process of directing energy to the target tissue site to form a lesion. The energy delivered may be in the form of radio frequency, microwave, ultrasound, light energy, and cryogenics, among others. In the case of the treatment of cardiac disfunction, lesions of different shape and size have been used to treat atrial fibrillation and ventricular tachycardia, among others.
Percutaneous transluminal ablation (PTA) catheters are frequently used for cardiac tissue ablation. The PTA catheters are long, slender, and flexible such that they can be inserted through a small incision through the skin into a blood vessel, such as an artery or vein, and advanced to the treatment site. Once positioned, the PTA catheter is used to selectively ablate or “burn” selected tissue which results in a change in the physiology of the treatment site. Such treatments may be used to block electrical conduction to correct abnormal cardiac rhythm that interferes with proper organ function.
PTA catheters use any of a number of methods to deliver ablative energy to the tissue. Some of these methods utilize radio frequency and microwave. The energy delivery component of the PTA catheter, sometimes referred to as an ablating element or electrode, is located either at the distal tip or along a portion of the distal end of the PTA catheter. When the PTA catheter is advanced through the blood vessel to the treatment site, either the tip or the side of the PTA catheter, depending on electrode type, is pressed against the tissue to be ablated.
Creation of linear lesions in the right and left atrium results in a progressive increase in the organization of atrial activity until sinus rhythm is restored. M. Haissaguerre, et al., reported successful ablation of atrial fibrillation in a patient with paroxysmal atrial fibrillation by the creation of three linear lesions in the right atrium, two longitudinal and one transverse, that connected the two longitudinal lesions using a specially designed catheter (Haissaguerre M, Gencel L, Fischer B, Metayer P L, Poquet F, Marcus F I, Clementy J., Successful Catheter Ablation of Atrial Fibrillation, J Cardiovasc Electrophysiol 1994;5:1045-1052).
Successful ablation therapy is defined as a return to normal sinus rhythm. To achieve this, lesions need to be continuous, transmural, and connected with other lesions or anatomical structures that cause blockage of atrial conduction. The seven recommended lesions are as follows: 1) right atrial isthmus ablation: linear lesion applied to the right atrium between the tricuspid annulus and the eustachian ridge, 2) right atrial inter-caval ablation: linear lesion applied along the posterior wall of the right atrium, between the superior vena cava and the inferior vena cava, 3) right pulmonary vein ablation (RPV): linear lesion applied to the left atrium, beginning below Bachmann's bundle, across the right superior pulmonary vein (RSPV) to the right inferior pulmonary vein (RIPV) and adjoining the mitral annulus, 4) left pulmonary vein ablation (LPV): linear lesion applied to the left atrium, beginning below Bachmann's bundle, across the left superior pulmonary vein (LSPV) to the left inferior pulmonary vein (LIPV) and reaching the mitral annulus, 5) superior pulmonary vein ablation (SPV): linear lesion applied to the left atrium, across the right superior pulmonary vein to the left superior pulmonary vein, 6) left atrial roof ablation (ROOF): linear lesion applied from the trigone, across the roof of the left atrium, to the left superior pulmonary vein, and 7) left atrial septal ablation (SEP): linear lesion applied to the foramen ovale to the right superior pulmonary vein. During creation of the right atrial inter-caval line, pacing is performed from each pair of electrodes at high output to assure the absence of diaphragmatic stimulation.
PTA catheters are designed for and have been used successfully for transluminal use; that is, via minimally invasive surgery. There is a need to have the capability to apply ablation therapy non-transluminally, such as during open heart surgery. For example, some patients having surgery for the treatment of atrio-ventricular valve disease would benefit from ablation therapy in order to correct cardiac arrhythmias of the atria or ventricle. Up to 40% of patients requiring mitral valve replacement have concurrent atrial fibrillation (fast atrial arrhythmia) which can be treated by creation of long linear ablation lines in the atria. During the open heart procedure, the physician is presented with a direct view of the target tissue to which ablation therapy may be applied, negating the need to approach the site transluminally. PTA catheters are inadequate for use in the open heart procedure, as they lack the structural support required to direct and press the electrodes against the target site. Also, due to their need to traverse narrow, tortuous vasculature, there is a definite limitation as to electrode size, shape and configuration available from PTA catheters.
SUMMARY
In general, the present tool and associated methods provide for precisely controlled positioning of an ablative element, or an array of ablative elements, against a tissue targeted for treatment. Such treatment is in the form of a lesion, caused by energy emitted from the ablative element, selectively changing or destroying cells within the target tissue.
The present tool and associated methodology provides a precise, controlled medical treatment which is suitable for destroying cells of medically targeted tissues throughout the body, both within and external to body organs. The tool is particularly useful for treating cardiac disfunction, such as atrial fibrillation, and the tool and its use are hereinafter described with respect to cardiac treatment, for purposes of simplifying the description thereof. The direct visualization and exposure of the heart tissue as provided during open heart procedures allow for a more direct and simplified approach to ablation on either the endocardium or epicardium. The lesions produced may be similar to those provided by ablation catheters or may be very different, taking advantage of the accessibility provided by the open heart procedure. For example, the isolation of the pulmonary veins from the rest of the atria could be accomplished in a very different fashion with a direct sight ablation tool as compared with ablation catheter techniques. It will be readily apparent to a person skilled in the art that the tool can be used to change or destroy body tissues in any body cavity or tissue locations that are accessible by invasive surgery, and is not limited to the heart. Application of the tool in all of these organs and tissues is intended to be included within the scope of this invention.
One aspect of the tool and associated methodologies provides for creating lesions of complex shape and size. This provides the surgeon with the ability to create the necessary lesion pattern with one or a few applications of the tool, as opposed to the multiple and repetitious application required of percutaneous transluminal ablation (PTA) catheters used currently. The tool incorporates an element array. This element array consists of one or more energy emitting (ablative) elements. The energy delivered may be in the form of radio frequency, microwave, ultrasound, light energy, and cryogenics, among others. The element array may also incorporate one or more temperature sensing elements, such as thermocouples and thermistors. Further, this element array may incorporate a fluid system providing recirculative cooling or fluid delivery to cool the element array and/or surrounding tissue.
In one embodiment, the element array consists of a single energy emit

Affiliated with

Also associated with

Rating

Ablation tool for forming lesions in body tissue does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Ablation tool for forming lesions in body tissue, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ablation tool for forming lesions in body tissue will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2529484