Energy delivery devices and methods

Abstract

This relates to methods and devices for achieving contact between the wall of a cavity or passageway and a medical device when used in tortuous anatomy.

Description

BACKGROUND OF THE INVENTION [0001] Asthma is a disease in which (i) bronchoconstriction, (ii) excessive mucus production, and (iii) inflammation and swelling of airways occur, causing widespread but variable airflow obstruction thereby making it difficult for the asthma sufferer to breathe. Asthma is a chronic disorder, primarily characterized by persistent airway inflammation. However, asthma is further characterized by acute episodes of additional airway narrowing via contraction of hyper-responsive airway smooth muscle. [0002] Asthma is managed pharmacologically by: (1) long term control through use of anti-inflammatories and long-acting bronchodilators and (2) short term management of acute exacerbations through use of short-acting bronchodilators. Both of these approaches require repeated and regular use of the prescribed drugs. High doses of corticosteroid anti-inflammatory drugs can have serious side effects that require careful management. In addition, some patients are resi...

AI Technical Summary

Benefits of technology

"The present invention provides devices for treating airways and other anatomical structures with uniform or predictable contact between the active element and tissue. These devices have a flexible elongate shaft that can navigate through tortuous anatomy with ease. The energy transfer elements can be expanded to properly treat the target site with low force advancement of the distal end of the shaft out of the far end of the sheath. The invention also includes a connector for coupling the energy transfer element to the power supply, and a design that allows for repeatable deployment of the expandable energy transfer element while maintaining its orientation and profile. These devices increase effectiveness and efficiency in carrying out a medical procedure."

Problems solved by technology

Asthma is a disease in which (i) bronchoconstriction, (ii) excessive mucus production, and (iii) inflammation and swelling of airways occur, causing widespread but variable airflow obstruction thereby making it difficult for the asthma sufferer to breathe.

High doses of corticosteroid anti-inflammatory drugs can have serious side effects that require careful management.

The difficulty involved in patient compliance with pharmacololgic management and the difficulty of avoiding stimulus that triggers asthma are common barriers to successful asthma management.

Current management techniques are neither completely successful nor free from side effects.

Tortuous anatomy also poses challenges when the treatment device requires mechanical actuation of the treatment portion (e.g., expansion of a treatment element at a remote site).

In particular, attempting to actuate a member may be difficult in view of the fact that the force applied at the operator's hand-piece must translate to the distal end of the device.

Accordingly, when energy or force is applied to move two polymers against each other, a significant part of friction between the polymers is the energy loss through inelastic hysteresis.

In addition, adhesion between polymers also plays a significant part in the friction between such polymers.

Yet, variances in the construction of the treatment device may hinder proper alignment or orientation of the device.

However, in this case, design or manufacturing variances may tend to produce a device where the angle between basket elements is not uniform.

This problem tends to be exacerbated after repeated actuation of the device and / or navigating the device through tortuous anatomy when the imperfections of the device become worsened through plastic deformation of the individual components.

Experience demonstrates that once a member becomes predisposed to splaying (i.e., not maintaining the desired angular separation from an adjacent element), or inverting (i.e., buckling inward instead of deploying outward), the problem is unlikely to resolve itself without requiring attention by the operator.

This interruption tends to increase the time of the treatment session.

However, the tortuous nature of the airways was found to cause significant bending and / or flexure of the distal end of the device.

For many treatment devices, the distortion of the energy transfer elements might cause variability in the treatment effect.

This directly affects the extent to which the tissue is heated.

In any number of cases, variability of the energy transfer / tissue interface causes variability in treatment results.

The consequential risks range from an ineffective treatment to the possibility of patient injury.

Therefore, distortion of the transfer element or elements increases the procedure time when the practitioner spends an inordinate amount of time adjusting a device to compensate for or avoid such distortion.

Such action becomes increasingly problematic in those cases where proper patient management limits the time available for the procedure.

For example, if a patient requires an increasing amount of medication (e.g., sedatives or anesthesia) to remain under continued control for performance of the procedure, then a medical practitioner may limit the procedure time rather than risk overmedicating the patient.

Subsequently, increasing the number of sessions poses additional consequences on the part of the patient in cost, the residual effects of any medication, adverse effects of the non-therapeutic portion of the procedure, etc.

Images