# Patent

## Title
Non-invasive and minimally invasive denervation methods and systems for performing the same

## Abstract

A system and method can be used to denervate at least a portion of a bronchial tree. An energy emitter of an instrument is percutaneously delivered to a treatment site and outputs energy to damage nerve tissue of the bronchial tree. The denervation procedure can be performed without damaging non-targeted tissue. Minimally invasive methods can be used to open airways to improve lung function in subjects with COPD, asthma, or the like. Different sections of the bronchial tree can be denervated while leaving airways intact to reduce recovery times.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/260,350 filed Nov. 11, 2009. This provisional application is incorporated herein by reference in its entirety.


BACKGROUND
1. Technical Field
The present invention generally relates to non-invasive and minimally invasive denervation methods and systems and apparatuses for performing those methods.
2. Description of the Related Art
Pulmonary diseases may cause a wide range of problems that adversely affect performance of the lungs. Pulmonary diseases, such as asthma and chronic obstructive pulmonary disease (“COPD”), may lead to increased airflow resistance in the lungs. Mortality, health-related costs, and the size of the population having adverse effects due to pulmonary diseases are all substantial. These diseases often adversely affect quality of life. Symptoms are varied and often include cough, breathlessness, and wheeze. In COPD, for example, breathlessness may be noticed when performing somewhat strenuous activities, such as running, jogging, brisk walking, etc. As the disease progresses, breathlessness may be noticed when performing non-strenuous activities, such as walking. Over time, symptoms of COPD may occur with less and less effort until they are present all of the time, thereby severely limiting a person's ability to accomplish normal tasks.
Pulmonary diseases are often characterized by airway obstruction associated with blockage of an airway lumen, thickening of an airway wall, alteration of structures within or around the airway wall, or combinations thereof. Airway obstruction can significantly decrease the amount of gas exchanged in the lungs resulting in breathlessness. Blockage of an airway lumen can be caused by excessive intraluminal mucus or edema fluid, or both. Thickening of the airway wall may be attributable to excessive contraction of the airway smooth muscle, airway smooth muscle hypertrophy, mucous glands hypertrophy, inflammation, edema, or combinations thereof. Alteration of structures around the airway, such as destruction of the lung tissue itself, can lead to a loss of radial traction on the airway wall and subsequent narrowing of the airway.
Asthma can be characterized by contraction of airway smooth muscle, smooth muscle hypertrophy, excessive mucus production, mucous gland hypertrophy, and/or inflammation and swelling of airways. These abnormalities are the result of a complex interplay of local inflammatory cytokines (chemicals released locally by immune cells located in or near the airway wall), inhaled irritants (e.g., cold air, smoke, allergens, or other chemicals), systemic hormones (chemicals in the blood such as the anti-inflammatory cortisol and the stimulant epinephrine), local nervous system input (nerve cells contained completely within the airway wall that can produce local reflex stimulation of smooth muscle cells and mucous glands and can contribute to inflammation and edema), and the central nervous system input (nervous system signals from the brain to smooth muscle cells, mucous glands and inflammatory cells carried through the vagus nerve). These conditions often cause widespread temporary tissue alterations and initially reversible airflow obstruction that may ultimately lead to permanent tissue alteration and permanent airflow obstruction that make it difficult for the asthma sufferer to breathe. Asthma can further include acute episodes or attacks of additional airway narrowing via contraction of hyper-responsive airway smooth muscle that significantly increases airflow resistance. Asthma symptoms include recurrent episodes of breathlessness (e.g., shortness of breath or dyspnea), wheezing, chest tightness, and cough.
Emphysema is a type of COPD often characterized by the alteration of lung tissue surrounding or adjacent to the airways in the lungs. Emphysema can involve destruction of lung tissue (e.g., alveoli tissue such as the alveolar sacs) that leads to reduced gas exchange and reduced radial traction applied to the airway wall by the surrounding lung tissue. The destruction of alveoli tissue leaves areas of emphysematous lung with overly large airspaces that are devoid of alveolar walls and alveolar capillaries and are thereby ineffective at gas exchange. Air becomes “trapped” in these larger airspaces. This “trapped” air may cause over-inflation of the lung, and in the confines of the chest restricts the in-flow of oxygen rich air and the proper function of healthier tissue. This results in significant breathlessness and may lead to low oxygen levels and high carbon dioxide levels in the blood. This type of lung tissue destruction occurs as part of the normal aging process, even in healthy individuals. Unfortunately, exposure to chemicals or other substances (e.g., tobacco smoke) may significantly accelerate the rate of tissue damage or destruction. Breathlessness may be further increased by airway obstruction. The reduction of radial traction may cause the airway walls to become “floppy” such that the airway walls partially or fully collapse during exhalation. An individual with emphysema may be unable to deliver air out of their lungs due to this airway collapse and airway obstructions during exhalation.
Chronic bronchitis is a type of COPD that can be characterized by contraction of the airway smooth muscle, smooth muscle hypertrophy, excessive mucus production, mucous gland hypertrophy, and inflammation of airway walls. Like asthma, these abnormalities are the result of a complex interplay of local inflammatory cytokines, inhaled irritants, systemic hormones, local nervous system, and the central nervous system. Unlike asthma where respiratory obstruction may be largely reversible, the airway obstruction in chronic bronchitis is primarily chronic and permanent. It is often difficult for a chronic bronchitis sufferer to breathe because of chronic symptoms of shortness of breath, wheezing, and chest tightness, as well as a mucus producing cough.
Different techniques can be used to assess the severity and progression of pulmonary diseases. For example, pulmonary function tests, exercise capacity, and quality of life questionnaires are often used to evaluate subjects. Pulmonary function tests involve objective and reproducible measures of basic physiologic lung parameters, such as total airflow, lung volume, and gas exchange. Indices of pulmonary function tests used for the assessment of obstructive pulmonary diseases include the forced expiratory volume in 1 second (FEV1), the forced vital capacity (FVC), the ratio of the FEV1 to FVC, the total lung capacity (TLC), airway resistance and the testing of arterial blood gases. The FEV1 is the volume of air a patient can exhale during the first second of a forceful exhalation which starts with the lungs completely filled with air. The FEV1 is also the average flow that occurs during the first second of a forceful exhalation. This parameter may be used to evaluate and determine the presence and impact of any airway obstruction. The FVC is the total volume of air a patient can exhale during a forceful exhalation that starts with the lungs completely filled with air. The FEV1/FVC is the fraction of all the air that can be exhaled during a forceful exhalation during the first second. A FEV1/FVC ratio less than 0.7 after the administration of at least one bronchodilator defines the presence of COPD. The TLC is the total amount of air within the lungs when the lungs are completely filled and may increase when air becomes trapped within the lungs of patients with obstructive lung disease. Airway resistance is defined as the pressure gradient between the alveoli and the mouth to the rate of air flow between the alveoli and the mouth. Similarly, resistance of a given airway is defined as the ratio of the pressure gradient across the given airway to the flow of air through the airway. Arterial blood gases tests measure the amount of oxygen and the amount of carbon dioxide in the blood and are the most direct method for assessing the ability of the lungs and respiratory system to bring oxygen from the air into the blood and to get carbon dioxide from the blood out of the body.
Exercise capacity tests are objective and reproducible measures of a patient's ability to perform activities. A six minute walk test (6 MWT) is an exercise capacity test in which a patient walks as far as possible over a flat surface in 6 minutes. Another exercise capacity test involves measuring the maximum exercise capacity of a patient. For example, a physician can measure the amount of power the patient can produce while on a cycle ergometer. The patient can breathe 30 percent oxygen and the work load can increase by 5-10 watts every 3 minutes.
Quality of life questionnaires assess a patient's overall health and well being. The St. George's Respiratory Questionnaire is a quality of life questionnaire that includes 75 questions designed to measure the impact of obstructive lung disease on overall health, daily life, and perceived well-being. The efficacy of a treatment for pulmonary diseases can be evaluated using pulmonary function tests, exercise capacity tests, and/or questionnaires. A treatment program can be modified based on the results from these tests and/or questionnaires.
Treatments, such as bronchial thermoplasty, involve destroying smooth muscle tone by ablating the airway wall in a multitude of bronchial branches within the lung thereby eliminating both smooth muscles and nerves in the airway walls of the lung. The treated airways are unable to respond favorably to inhaled irritants, systemic hormones, and both local and central nervous system input. Unfortunately, this destruction of smooth muscle tone and nerves in the airway wall may therefore adversely affect lung performance. For example, inhaled irritants, such as smoke or other noxious substances, normally stimulate lung irritant receptors to produce coughing and contracting of airway smooth muscle. Elimination of nerves in the airway walls removes both local nerve function and central nervous input, thereby eliminating the lung's ability to expel noxious substances with a forceful cough. Elimination of airway smooth muscle tone may eliminate the airway's ability to constrict, thereby allowing deeper penetration of unwanted substances, such as noxious substances, into the lung.
Both asthma and COPD are serious diseases with growing numbers of sufferers. Current management techniques, which include prescription drugs, are neither completely successful nor free from side effects. Additionally, many patients do not comply with their drug prescription dosage regiment. Accordingly, it would be desirable to provide a treatment which improves resistance to airflow without the need for patient compliance.
BRIEF SUMMARY
Some embodiments are directed to non-invasive or minimally invasive denervation procedures. The denervation procedures can be performed without causing trauma that results in significant recovery periods. Non-invasive denervation methods can involve delivering energy from energy sources positioned external to the subject. The energy is aimed at targeted tissue to minimize, limit, or substantially eliminate appreciable damage to non-targeted tissue. Minimally invasive denervation procedures can involve percutaneously delivering an instrument.
Denervation of hollow organs, such as the lung bronchus, can be due to the creation of lesions with radiofrequency ablation that are of a sufficient depth when generated on the outside of the organ to penetrate the adventitial tissue layers where nerve trunks are anatomically located. In the example of lung denervation, ablating nerve trunks along the outside of both the right and left main bronchi effectively disconnects airway smooth muscle which lines the inside of the lung airways and mucus producing glands located with the airways from the vagus nerve. When this occurs, airway smooth muscle relaxes and mucus production is decreased. Nervous system mediated inflammation and edema will decrease as well. These changes reduce airway obstruction for subjects with COPD, asthma, or the like. Reduced airway obstruction makes breathing easier which improves the subject's quality of life and health status. Tests and questionnaires can be used to evaluate and monitor the subject's health.
Some embodiments are directed to a percutaneously deliverable apparatus capable of performing a denervation procedure. The apparatus can ablate targeted nerve tissue to denervate at least a portion of a lung. A minimally invasive access device can be used to percutaneously deliver the apparatus and can be a needle, a trocar, a robotic catheter, a mediastinoscope, a port, or a thoracoscope. Direct or remote visualization techniques (e.g., ultrasound guidance, endoscopy, radiologic guidance, etc.) can be used to position the apparatus.
The apparatus can be an instrument insertable directly into a hollow organ (e.g., through the mouth and into the esophagus or stomach) or inserted through the instrument channel of an endoscope (e.g., gastroscope, esophagoscope, or the like). The instrument has a flexible elongate shaft that carries one or more ablation elements. The ablation elements can be energy emitters, such as electrodes. The apparatus can be delivered through an opening in the subject's chest. The instrument can be brought into direct contact with the outer surface of the bronchial tree or lung while extending through the hollow organ.
The apparatus can be an instrument insertable directly into a large peripheral artery (e.g., femoral artery, brachial artery, or the like) and advanced through the arterial tree, into the aorta, and then into one or more bronchial arteries traveling along the main stem bronchi. The instrument has a flexible elongate shaft that carries one or more ablation elements. The ablation elements can be energy emitters, such as electrodes. The bronchial arteries are often located in close proximity to the vagus nerve trunks traveling along the outside of the bronchial tree. Placement of the instrument in one or more bronchial arteries brings the instrument with its ablation elements into close proximity to the vagus nerve trunks traveling along the outside of the bronchial tree. Advancement of the instrument and placement in the bronchial arteries can be guided by a variety of imaging modalities (e.g., fluoroscopy, ultrasound, CT scans, or the like).
In some embodiments, an instrument has an activatable section capable of intimately contacting a surface of an airway (either an outer surface or an inner surface). The activatable section can include one or more selectively activatable energy emitters, ablation elements, or the like. The activatable section can preferentially treat the posterior portion of the main lung airways or other targeted region(s) of airways.
A system for treating a subject includes an extraluminal elongate assembly dimensioned to move around the outside of the airway of a bronchial tree and an access device. The elongate assembly is adapted to attenuate signals transmitted by nerve tissue, such as nerve tissue of nerve trunks, while not irreversibly damaging adjacent anatomical structures. The elongate assembly can include at least one ablation element, which includes one or more electrodes operable to output radiofrequency energy.
Some methods involve minimally invasive denervation of at least a portion of a lung. The method comprises damaging nerve tissue of a first main bronchus to substantially prevent nervous system signals from traveling to most or substantially all distal bronchial branches connected to the first main bronchus. The nerve tissue, in certain embodiments, is positioned between a trachea and a lung through which the bronchial branches extend. The airway can remain intact while the nerve tissue is damaged.
The method, in some embodiments, further includes damaging nerve tissue of a second main bronchus to substantially prevent nervous system signals from traveling to most or substantially all distal bronchial branches connected to the second main bronchus. An apparatus used to damage the nerve tissue can be percutaneously delivered with the assistance of sonographic guidance, radiologic guidance, robotic guidance, mediastinoscopic guidance, thoracoscopic guidance, or other minimally invasive surgery visualization techniques.
In some embodiments, a method for treating a subject includes moving a tip of an instrument through at least a portion of a subject's skin to position the instrument next to nerve tissue. A desired amount of nerve tissue can then be damaged using the instrument. Some methods include damaging nerve tissue along a right main bronchus and ablating nerve tissue along the left main bronchus to denervate a significant portion of the bronchial tree. In other embodiments, denervating a portion of the bronchial tree comprises destroying at least one nerve trunk at a position that is within at least one of the left and right lung. The denervation process, in some embodiments, is performed without permanently damaging other tissue structures. In some denervation procedures, substantially all of the nerve trunks extending along a tubular section of an airway are damaged to prevent substantially all nervous system signals transmitted along the airway from traveling past the denervated portion without destroying the airway.
In yet other embodiments, a method for denervating a bronchial tree of a subject includes moving an energy emitter of an instrument through the subject's skin. The energy emitter is positioned proximate to an airway. Nerve tissue of the bronchial tree is damaged using the energy emitter while the energy emitter is positioned outside of the airway. The energy emitter can output a sufficient amount of at least one of radiofrequency energy, microwave energy, radiation energy, high intensity focused ultrasound energy (HIFU), thermal energy, or combinations thereof to damage the nerve tissue. In radiofrequency ablation, the instrument may cool and protect nontargeted tissue. High intensity focused ultrasound energy can be delivered to specific targeted tissue to mitigate damage of nontargeted tissue. The instrument is removed from the subject, leaving the airway intact.
Non-invasive denervation methods can be used to denervate a subject's lungs. An external energy source can deliver energy to targeted tissue to form lesions. The lesions can be formed at a depth of 1 mm to 2 mm along an airway to insure that a nerve trunk is destroyed without destroying the entire airway wall.
A method in some embodiments comprises moving a distal section of an instrument through a subject's skin. Most of a bronchial tree is denervated using the instrument to substantially prevent nervous system signals from traveling to substantially all branches of the bronchial tree. The distal section can be percutaneously delivered to minimize trauma and reduce recovery time. The method can be performed without severing airways, removing airways, or otherwise damaging the entire circumference of the denervated airway. In some embodiments, the entire procedure is performed without severing the entire airway. The airway can continue to function after the procedure.
A denervation method includes moving an energy emitter of an instrument through the subject's skin. Nerve tissue is altered (e.g., damaged, ablated, etc.) using energy from the energy emitter while the energy emitter is positioned outside of an airway or organ. The instrument is removed from the subject without destroying the airway or organ. In certain embodiments, the airway remains intact through the entire denervation process such that the airway maintains the health of distal portions of the lung. The denervation method can be used to denervate one or both lungs.
In some embodiments, a distal section of an instrument is wrapped around an airway to position at least one energy emitter with respect to nerve tissue. The energy emitter can output energy to damage the nerve tissue. Visualization can be used to view the airway. In certain embodiments, the outside of the airway is visualized while performing an ablation procedure or positioning the energy emitter. Visualization can be achieved using at least one of a thoracoscope, an ultrasonic device, and a fluoroscopy system.
A wide range of different types of body structures can be treated using energy. Non-limiting exemplary body structures include airways, the trachea, esophagus, vessels (e.g., blood vessels), the urethra, or other targeted structures. In certain embodiments, an instrument is endovascularly positioned in a blood vessel to position a distal portion of the instrument proximate to an airway nerve or other target region. Energy is delivered from the instrument to damage the airway nerve such that nerve signals to the airway are attenuated.
In some embodiments, a method for denervating a bronchial tree or other body structure of a subject includes moving an energy emitter of an instrument through the subject's skin. Nerve tissue is damaged using energy from the energy emitter while the energy emitter is positioned outside of the airway or body structure. In certain procedures, the instrument is removed from the subject without severing the entire airway. The procedure can be performed without puncturing the wall of the airway or body structure.
In yet other embodiments, a method for treating a subject comprises delivering emitting energy from an external energy source positioned outside of the subject's body through the subject's skin towards targeted nerve tissue of a bronchial tree. The nerve tissue is damaged using the energy while the external energy source is outside the subject's body. The external energy source can be placed against or spaced apart from the subject's skin.
In further embodiments, a method comprises percutaneously delivering a distal section of an instrument through a subject's skin such that the distal section is positioned to damage nerve tissue of a bronchial tree, blood vessel, or other body structure. In bronchial tree procedures, at least a portion of a bronchial tree in a subject's lung is denervated using the instrument to substantially prevent nervous system signals from traveling to a portion of the bronchial tree. In vascular procedures, a catheter is endovascularly positioned a in a blood vessel to position a distal portion of the catheter proximate to an airway nerve. The catheter is used to ablate nerve tissue.
In certain embodiments, an instrument is endovascularly positioned in a blood vessel (e.g., a bronchial artery or other vessel) to position a distal portion of the instrument proximate to an airway structure, such as a nerve. Energy is delivered from the instrument to damage the airway nerve such that nerve signals to the airway are attenuated. Other tissues can also be targeted.
One or more electrodes carried by the distal portion of the catheter can output radiofrequency energy or ultrasound energy. The electrode can be coupled to an outside surface of the distal portion or positioned within the distal portion. By delivering the energy, nerve signals can be attenuated so as to reduce constriction of the airway. In some embodiments, the constriction is permanently eliminated. In yet other procedures, nerve signals are attenuated so as to inhibit constriction of smooth muscle in the airway.
In other procedures, an instrument is passed through a subject's mouth and into the esophagus. The distal section of the instrument can be manipulated to position the distal section of the instrument proximate to the bronchial tree. In certain embodiments, the distal section can push against the wall of the esophagus to position an ablation assembly proximate to the left main bronchus or the right main bronchus. Without puncturing the esophagus wall, the ablation assembly can deliver energy to the nerve tissue with or without employing differential cooling. The ablation assembly can remain within the lumen of the esophagus throughout the ablation process.
The instruments can be passed through openings in the esophagus, the trachea, the left main bronchus and/or the right main bronchus. To pass an instrument out of the trachea, an opening can be formed in the wall of the trachea. The instrument can be moved through the opening and proximate to nerve tissue of an airway. The nerve tissue can be ablated while the instrument extends through the trachea wall and alongside the airway. In other procedures, a puncture can be formed along the left and/or right main bronchus. The instrument can be delivered through the opening and can wrap around the bronchus to destroy or ablate tissue.



BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In the Figures, identical reference numbers identify similar elements or acts.
FIG. 1 is an illustration of lungs, blood vessels, and nerves near to and in the lungs.
FIG. 2 is an illustration of a system positioned to treat a left main bronchus.
FIG. 3 is a cross-sectional view of an airway of a bronchial tree taken along a line 3-3 of FIG. 2.
FIG. 4 is a cross-sectional view of a constricted airway and mucus is in an airway lumen and an instrument positioned next to the airway.
FIG. 5 is a cross-sectional view of an airway with an intraluminal instrument inside an airway and an instrument positioned outside the airway.
FIGS. 6-9 are side elevational views of distal sections of instruments.
FIG. 10 is an illustration of an instrument surrounding a left main bronchus.
FIG. 11 is a cross-sectional view of the left main bronchus of taken along a line 11-11 of FIG. 10.
FIG. 12 is an illustration of an external treatment system and a subject.



DETAILED DESCRIPTION
FIG. 1 illustrates human lungs 10 having a left lung 11 and a right lung 12. A trachea 20 extends downwardly from the nose and mouth and divides into a left main bronchus 21 and a right main bronchus 22. The left main bronchus 21 and right main bronchus 22 each branch to form lobar, segmental bronchi, and sub-segmental bronchi, which have successively smaller diameters and shorter lengths in the outward direction (i.e., the distal direction). A main pulmonary artery 30 originates at a right ventricle of the heart and passes in front of a lung root 24. At the lung root 24, the artery 30 branches into a left and right pulmonary artery, which in turn branch to form a network of branching blood vessels. These blood vessels can extend alongside airways of a bronchial tree 27. The bronchial tree 27 includes the left main bronchus 21, the right main bronchus 22, bronchioles, and alveoli. Vagus nerves 41, 42 extend alongside the trachea 20 and branch to form nerve trunks 45.
The left and right vagus nerves 41, 42 originate in the brainstem, pass through the neck, and descend through the chest on either side of the trachea 20. The vagus nerves 41, 42 spread out into nerve trunks 45 that include the anterior and posterior pulmonary plexuses that wrap around the trachea 20, the left main bronchus 21, and the right main bronchus 22. The nerve trunks 45 also extend along and outside of the branching airways of the bronchial tree 27. Nerve trunks 45 are the main stem of a nerve, comprising a bundle of nerve fibers bound together by a tough sheath of connective tissue.
The primary function of the lungs 10 is to exchange oxygen from air into the blood and to exchange carbon dioxide from the blood to the air. The process of gas exchange begins when oxygen rich air is pulled into the lungs 10. Contraction of the diaphragm and intercostal chest wall muscles cooperate to decrease the pressure within the chest to cause the oxygen rich air to flow through the airways of the lungs 10. For example, air passes through the mouth and nose, the trachea 20, then through the bronchial tree 27. The air is ultimately delivered to the alveolar air sacs for the gas exchange process.
Oxygen poor blood is pumped from the right side of the heart through the pulmonary artery 30 and is ultimately delivered to alveolar capillaries. This oxygen poor blood is rich in carbon dioxide waste. Thin semi-permeable membranes separate the oxygen poor blood in capillaries from the oxygen rich air in the alveoli. These capillaries wrap around and extend between the alveoli. Oxygen from the air diffuses through the membranes into the blood, and carbon dioxide from the blood diffuses through the membranes to the air in the alveoli. The newly oxygen enriched blood then flows from the alveolar capillaries through the branching blood vessels of the pulmonary venous system to the heart. The heart pumps the oxygen rich blood throughout the body. The oxygen spent air in the lung is exhaled when the diaphragm and intercostal muscles relax and the lungs and chest wall elastically return to the normal relaxed states. In this manner, air can flow through the branching bronchioles, the bronchi 21, 22, and the trachea 20 and is ultimately expelled through the mouth and nose.
A network of nerve tissue of the autonomic nervous system senses and regulates activity of the respiratory system and the vasculature system. Nerve tissue includes fibers that use chemical and electrical signals to transmit sensory and motor information from one body part to another. For example, the nerve tissue can transmit motor information in the form of nervous system input, such as a signal that causes contraction of muscles or other responses. The fibers can be made up of neurons. The nerve tissue can be surrounded by connective tissue, i.e., epineurium. The autonomic nervous system includes a sympathetic system and a parasympathetic system. The sympathetic nervous system is largely involved in “excitatory” functions during periods of stress. The parasympathetic nervous system is largely involved in “vegetative” functions during periods of energy conservation. The sympathetic and parasympathetic nervous systems are simultaneously active and generally have reciprocal effects on organ systems. While innervation of the blood vessels originates from both systems, innervation of the airways is largely parasympathetic in nature and travels between the lung and the brain in the right vagus nerve 42 and the left vagus nerve 41.
FIG. 2 shows a minimally invasive system 200 capable of treating the respiratory system to enhance lung function. The subject may suffer from COPD, asthma, or the like and, thus, the lungs 10 may perform poorly. To decrease air flow resistance to increase gas exchange, the system 200 can be used to perform a denervation procedure. A distal section 214 of an instrument 204 can affect nerve tissue, which can be part of a nerve trunk inside or outside of the lungs. The nerve tissue can be ablated to permanently dilate the airways and/or decrease airway mucus production or airway inflammation and edema.
The instrument 204 can be used to attenuate the transmission of signals traveling along the vagus nerves 41, 42 that cause or mediate muscle contractions, mucus 150 production, inflammation, edema, and the like. Attenuation can include, without limitation, hindering, limiting, blocking, and/or interrupting the transmission of signals. For example, the attenuation can include decreasing signal amplitude of nerve signals or weakening the transmission of nerve signals. Decreasing or stopping nervous system input to distal airways can alter airway smooth muscle tone, airway mucus production, airway inflammation, and the like, thereby controlling airflow into and out of the lungs 10. Decreasing or stopping sensory input from the airways and lungs to local effector cells or to the central nervous system can also decrease reflex bronchoconstriction, reflex mucous production, release of inflammatory mediators, and nervous system input to other cells in the lungs or organs in the body that may cause airway wall edema. In some embodiments, the nervous system input can be decreased to correspondingly decrease airway smooth muscle tone. In some embodiments, the airway mucus production can be decreased a sufficient amount to cause a substantial decrease in coughing and/or in airflow resistance. In some embodiments, the airway inflammation can be decreased a sufficient amount to cause a substantial decrease in airflow resistance and ongoing inflammatory injury to the airway wall. Signal attenuation may allow the smooth muscles to relax, prevent, limit, or substantially eliminate mucus production by mucous producing cells, and decrease inflammation. In this manner, healthy and/or diseased airways can be altered to adjust lung function. After treatment, various types of questionnaires or tests can be used to assess the subject's response to the treatment. If needed or desired, additional procedures can be performed to reduce the frequency of coughing, decrease breathlessness, decrease wheezing, and the like.
Main bronchi 21, 22 (i.e., airway generation 1) of FIGS. 1 and 2 can be treated to affect distal portions of the bronchial tree 27. In some embodiments, the left and right main bronchi 21, 22 are treated at locations along the left and right lung roots 24 and outside of the left and right lungs 11, 12. Treatment sites can be distal to where vagus nerve branches connect to the trachea and the main bronchi 21, 22 and proximal to the lungs 11, 12. A single treatment session involving two therapy applications can be used to treat most of or the entire bronchial tree 27. Substantially all of the bronchial branches extending into the lungs 11, 12 may be affected to provide a high level of therapeutic effectiveness. Because the bronchial arteries in the main bronchi 21, 22 have relatively large diameters and high heat sinking capacities, the bronchial arteries may be protected from unintended damage due to the treatment.
Nerve tissue distal to the main bronchi can also be treated, such as nerve tissue positioned outside the lung which run along the right or left main bronchi, the lobar bronchii, and bronchus intermedius. The intermediate bronchus is formed by a portion of the right main bronchus and includes origin of the middle and lower lobar bronchii. The distal section 214 can be positioned alongside higher generation airways (e.g., airway generations >2) to affect remote distal portions of the bronchial tree 27. Different procedures can be performed to denervate a portion of a lobe, an entire lobe, multiple lobes, or one lung or both lungs. In some embodiments, the lobar bronchi are treated to denervate lung lobes. For example, one or more treatment sites along a lobar bronchus may be targeted to denervate an entire lobe connected to that lobar bronchus. Left lobar bronchi can be treated to affect the left superior lobe and/or the left inferior lobe. Right lobar bronchi can be treated to affect the right superior lobe, the right middle lobe, and/or the right inferior lobe. Lobes can be treated concurrently or sequentially. In some embodiments, a physician can treat one lobe. Based on the effectiveness of the treatment, the physician can concurrently or sequentially treat additional lobe(s). In this manner, different isolated regions of the bronchial tree can be treated.
Each segmental bronchus may be treated by delivering energy to a single treatment site along each segmental bronchus. Nerve tissue of each segmental bronchus of the right lung can be destroyed. In some procedures, one to ten applications of energy can treat most of or substantially all of the right lung. Depending on the anatomical structure of the bronchial tree, segmental bronchi can often be denervated using one or two applications of energy.
Function of other tissue or anatomical features, such as the mucous glands, cilia, smooth muscle, body vessels (e.g., blood vessels), and the like can be maintained when nerve tissue is ablated. Nerve tissue includes nerve cells, nerve fibers, dendrites, and supporting tissue, such as neuroglia. Nerve cells transmit electrical impulses, and nerve fibers are prolonged axons that conduct the impulses. The electrical impulses are converted to chemical signals to communicate with effector cells or other nerve cells. By way of example, a portion of an airway of the bronchial tree 27 can be denervated to attenuate one or more nervous system signals transmitted by nerve tissue. Denervating can include damaging all of the nerve tissue of a section of a nerve trunk along an airway to stop substantially all the signals from traveling through the damaged section of the nerve trunk to more distal locations along the bronchial tree or from the bronchial tree more proximally to the central nervous system. Additionally, signals that travel along nerve fibers that go directly from sensory receptors (e.g., cough and irritant receptors) in the airway to nearby effector cells (e.g., postganglionic nerve cells, smooth muscle cells, mucous cells, inflammatory cells, and vascular cells) will also be stopped. If a plurality of nerve trunks extends along the airway, each nerve trunk can be damaged. As such, the nerve supply along a section of the bronchial tree can be cut off. When the signals are cut off, the distal airway smooth muscle can relax leading to airway dilation, mucous cells decrease mucous production, or inflammatory cells stop producing airway wall swelling and edema. These changes reduce airflow resistance so as to increase gas exchange in the lungs 10, thereby reducing, limiting, or substantially eliminating one or more symptoms, such as breathlessness, wheezing, chest tightness, and the like. Tissue surrounding or adjacent to the targeted nerve tissue may be affected but not permanently damaged. In some embodiments, for example, the bronchial blood vessels along the treated airway can deliver a similar amount of blood to bronchial wall tissues and the pulmonary blood vessels along the treated airway can deliver a similar amount of blood to the alveolar sacs at the distal regions of the bronchial tree 27 before and after treatment. These blood vessels can continue to transport blood to maintain sufficient gas exchange. In some embodiments, airway smooth muscle is not damaged to a significant extent. For example, a relatively small section of smooth muscle in an airway wall which does not appreciably impact respiratory function may be reversibly altered. If energy is used to destroy the nerve tissue outside of the airways, a therapeutically effective amount of energy does not reach a significant portion of the non-targeted smooth muscle tissue.
Any number of procedures can be performed on one or more of these nerve trunks to affect the portion of the lung associated with those nerve trunks. Because some of the nerve tissue in the network of nerve trunks coalesces into other nerves (e.g., nerves connected to the esophagus, nerves though the chest and into the abdomen, and the like), specific sites can be treated to minimize, limit, or substantially eliminate unwanted damage of other nerves. Some fibers of anterior and posterior pulmonary plexuses coalesce into small nerve trunks which extend along the outer surfaces of the trachea 20 and the branching bronchi and bronchioles as they travel outward into the lungs 10. Along the branching bronchi, these small nerve trunks continually ramify with each other and send fibers into the walls of the airways.
Referring to FIGS. 2 and 3, the distal section 214 is positioned within the chest outside of the airway 100. An activatable element in the form of an energy emitter 209 (illustrated in dashed line) is configured to damage nerve tissue 45, illustrated as a vagus nerve branch. Vagus nerve tissue includes efferent fibers and afferent fibers oriented parallel to one another within a nerve branch. The efferent nerve tissue transmits signals from the brain to airway effector cells, mostly airway smooth muscle cells and mucus producing cells. The afferent nerve tissue transmits signals from airway sensory receptors, which respond to irritants, and stretch to the brain. There is a constant, baseline tonic activity of the efferent vagus nerve tissues to the airways which causes a baseline level of smooth muscle contraction and mucous secretion.
The energy emitter 209 can ablate the efferent and/or the afferent tissues to control airway smooth muscle (e.g., innervate smooth muscle), mucous secretion, nervous mediated inflammation, and tissue fluid content (e.g., edema). The contraction of airway smooth muscle, excess mucous secretion, inflammation, and airway wall edema associated with pulmonary diseases often results in relatively high air flow resistance causing reduced gas exchange and decreased lung performance.
The instrument 204 can be delivered through a percutaneous opening in the chest, back, or other suitable location. Potential access locations include between the ribs in the chest, between the ribs in a para-sternal location, between the ribs along the back or side of the subject, from a subxiphoid location in the chest, or through the pre-sternal notch superior to the manubrium. As used herein, the term “percutaneous” and derivations thereof refer generally to medical procedures that involve accessing internal organs via an opening, such as a puncture or small incision in a subject's skin and may involve the use of an access apparatus, such as the access apparatus 210. The access apparatus 210 can be in the form of a trocar, a cannula, a port, a sleeve, or other less-invasive access device, along with an endoscope, a thoracoscope, or other visualization device. The distal section 214 can be relatively sharp to puncture and pass through tissue. A stylet can be positioned in a lumen in the instrument 204 and can have a relatively sharp tip to directly puncture the skin. After the stylet is inserted into the skin, the instrument 204 can be moved along the stylet through the user's skin into and between internal organs.
The instrument 204 may be visualized using fluoroscopy, computed tomography (CT), thoracoscopy, ultrasound, or other imaging modalities, and may have one or more markers (e.g., radiopaque marks), or dyes (e.g., radiopaque dyes), or other visual features. The visual features can help increase the instrument's visibility, including the instrument's radiopacity or ultrasonic visibility.
An instrument shaft 207 of FIG. 2 can be made of a generally flexible material to allow delivery along tortuous paths to remote and deep sites. The distal section 214 can be steered or otherwise manipulated using a steering assembly 208. The distal section 214 can be deflected laterally or shaped into a desired configuration to allow enhanced navigation around thoracic structures. To deliver energy to a treatment site, the distal section 214 can assume a treatment configuration. The treatment configuration can be a serpentine configuration, a helical configuration, a spiral configuration, a straight configuration, or the like. U.S. patent application Ser. No. 12/463,304, filed on May 8, 2009, and U.S. patent application Ser. No. 12/913,702, filed on Oct. 27, 2010, describe catheters and apparatuses that can assume these types of configurations and can be used to perform the methods disclosed herein. Each of these applications is incorporated by reference in its entirety. Conventional electrode catheters or ablation catheters can also be used to perform at least some methods disclosed herein.
To damage nerve tissue 45, the distal section 214 can be at different orientations, including transverse to the nerve trunk 45, generally parallel to the nerve trunk 45, or any other suitable orientation with respect to the airway 100. If the tissue is ablated using chemicals, the distal section 214 can puncture the nerve trunk 45 and deliver the agent directly to nerve tissue.
As used herein, the term “energy” is broadly construed to include, without limitation, thermal energy, cryogenic energy (e.g., cooling energy), electrical energy, acoustic energy (e.g., ultrasonic energy), microwave energy, radiofrequency energy, high voltage energy, mechanical energy, ionizing radiation, optical energy (e.g., light energy), and combinations thereof, as well as other types of energy suitable for treating tissue. The energy emitter 209 of FIG. 3 can include one or more electrodes (e.g., needle electrodes, bipolar electrodes, or monopolar electrodes) for outputting energy, such as ultrasound energy, radiofrequency (RF) energy, radiation, or the like. The electrodes can output a sufficient amount of RF energy to form a lesion at the periphery of the airway 100. To avoid damaging smooth muscle tissue, a lesion 219 (shown in phantom line in FIG. 3) can have a depth less than or equal to about 2 mm. In some embodiments, the lesion depth D can be less than about 1 mm to localize tissue damage. Thermal energy emitters 209 can be resistive heaters or thermally conducting elements. To treat tissue with microwave energy, the energy emitter 209 can include one or more microwave antennas. In optical embodiments, the energy emitter 209 includes one or more lenses or reflector(s) capable of outputting light delivered via one or more optical fibers. An external light source (e.g., a lamp, an array of light emitting diodes, or the like) can output light that is delivered through the shaft 207 to the energy emitter 209. In other embodiments, the energy emitter 209 is a light source, such as a light-emitting diode (LED) or laser diode. Photodynamic agents or light activatable agents can be used to ablate tissue. In yet other embodiments, the energy emitter 209 can include a dispenser (e.g., a nozzle, an orifice, etc.) for delivering a substance (e.g., a chemical agent, a high temperature fluid, a cutting jet, etc.) that kills or damages targeted tissue. Multiple emitters can be used sequentially or simultaneously to treat tissue. For example, an energy emitter in the form of a dispenser can mechanically damage surface tissue while another energy emitter outputs radiofrequency or microwave energy to destroy deep tissue.
For mechanical denervation, the distal section 214 can mechanically damage tissue by cutting, abrading, or tearing nerve tissue. A minimal amount of tissue adjacent to the nerve tissue 45 may also be damaged. The damaged non-targeted tissue can heal without any appreciable decrease in lung function. In embodiments, the distal section 214 comprises a morcellation device.
The distal section 214 can comprise one or more energy absorption devices for absorbing energy from a remote energy source. The remote energy source can be a microwave energy source, a radiofrequency energy source, an ultrasound energy source, or a radiation energy source and can be positioned outside the subject's body or located in another body structure, such as the esophagus, airway (trachea or bronchus), or elsewhere in the subject's body. The distal section 214 can be heated by the remote energy source to a sufficient temperature to damage targeted tissue. Additionally or alternatively, the element 209 can include a reflector to reflect energy from a remote energy source. The reflected energy can create a pattern (e.g., interference pattern) to control the amplitude of energy waves at the target site.
With continued reference to FIG. 2, the controller 221 can include one or more processors, microprocessors, digital signal processors (DSPs), field programmable gate arrays (FPGA), and/or application-specific integrated circuits (ASICs), memory devices, buses, power sources, and the like. For example, the controller 221 can include a processor in communication with one or more memory devices. Buses can link an internal or external power supply to the processor. The memories may take a variety of forms, including, for example, one or more buffers, registers, random access memories (RAMs), and/or read only memories (ROMs). The controller 221 may also include a display, such as a screen, and can be a closed loop system, whereby the power to the distal section 214 is controlled based upon feedback signals from one or more sensors 212 (see FIG. 3) configured to transmit (or send) one or more signals indicative of one or more tissue characteristics, energy distribution, tissue temperature, or any other measurable parameters of interest. Based on those readings, the controller 221 can then adjust operation of the distal section 214. By way of example, the controller 221 can control the amount of energy delivered from the energy source 217 (e.g., one or more batteries or other energy storage devices) to the energy emitter 209. The sensor 212 can be a temperature sensor. If the temperature of the peripheral tissue of the airway 100 becomes too hot, the distal section 214 can cool the tissue using one or more Peltier devices, cooling balloons, or other types of cooling features. Current sensors or voltage sensors 212 can be used to measure the tissue impedance. Alternatively, the controller 221 can be an open loop system wherein the operation is set by user input. For example, the system 200 may be set to a fixed power mode. It is contemplated that the system 200 can be repeatedly switched between a closed loop mode and an open loop mode to treat different types of sites.
The instrument 204 can also include any number of different types of visualization devices, such as cameras, optical fibers, lenses, or mirrors. Ultrasound or other types of energy-based viewing systems can be used to visualize deep targeted tissues. Surface tissues can be targeted using direct visualization while deeper tissues are subsequently targeted using ultrasound.
FIG. 4 shows a constricted, edematous and mucous filled airway 100 that can be dilated and can have mucous production and edema decreased by ablating the nerve tissue 45. As used herein, the term “ablate,” including variations thereof, refers, without limitation, to destroying or permanently damaging, injuring, or traumatizing tissue. For example, ablation may include localized tissue destruction, cell lysis, cell size reduction, necrosis, or combinations thereof. In the context of pulmonary ablation applications, the term “ablation” includes sufficiently altering nerve tissue properties to substantially block transmission of electrical signals through the ablated nerve tissue. Ablating all of the nerve trunks along the airway prevents nerve signals from traveling distally along the airway 100 and causes the smooth muscle 114 to relax to open the airway 100.
In RF ablation, RF energy causes heating of the nerve tissue 45 and, ultimately, the formation of the lesion 219. The nerve tissue is destroyed without removing a significant amount of airway tissue, if any, to preserve the integrity of the airway 100. The lesion 219 can be left in the body to avoid potential complications from removing airway tissue. The healthy airway wall 103 prevents gas escape across the airway wall 103. The smooth muscle and interior lining of the airway 100 can remain substantially undamaged to allow mucociliary transport and other bodily functions that are important to overall health. This reduces the recovery time and avoids or mitigates problems associated with surgical techniques of removing or cutting through the airway wall. In contrast to lung resection procedures in which entire airways are severed and removed, an intact denervated airway 100 can also ensure that distal regions of the lung continue to function.
Large lesions can extend through the airway wall and can be formed to destroy unwanted tissue (e.g., cancerous tissues) positioned along the inner surface. Differential cooling can be used to form lesions buried deep within the sidewall 103, spaced apart from the interior and exterior surfaces of the airway 100, or any other suitable location. U.S. patent application Ser. No. 12/463,304, filed on May 8, 2009, and U.S. patent application Ser. No. 12/913,702, filed on Oct. 27, 2010 discloses various catheters and differential cooling techniques. The instrument 204 can cool tissues to keep the nontargeted tissue below a temperature at which cell death occurs. In some embodiments, the distal section 214 has a cooling member (e.g., a cooling balloon) that absorbs thermal energy to keep nontargeted regions of the airway wall 103 at or below a desired temperature. The shape and size of lesions can also be adjusted as desired.
Natural body functions can help prevent, reduce, or limit tissue damage. If the bronchial artery branch 130 is heated, blood within the blood vessels 130 can absorb the thermal energy and can then carry the thermal energy away from the heated section of the branches 130. The lesion 219 can surround a region of the blood vessel 130 without destroying the vessel 130. After the treatment is performed, the bronchial artery branches 130 can continue to maintain the health of lung tissue.
The lesion depth D of FIG. 4 can be kept at or below a desired depth by controlling the amount of delivered energy. To avoid reaching smooth muscle 114, the depth D can be equal to or less than about 3 mm, 2 mm, or 1 mm. For thick airway walls, the lesion depth D can be equal to or less than about 3 mm. For medium size airway walls, the lesion depth D can be equal to or less than about 2 mm. In young children with thin airway walls, the lesion depth D can be equal to or less than about 1 mm. The lateral dimensions (e.g., width, length, etc.) of the lesion 219 can be adjusted to ensure that targeted tissue is ablated.
FIG. 5 shows a system that includes a pair of separately deliverable instruments 310, 312. The instrument 312 can be generally similar to the instrument 204 of FIGS. 2-4, unless indicated otherwise. The instrument 310 can be an intraluminal catheter deliverable through a lumen 101 defined by an inner surface 102 of the airway 100. The illustrated inner surface 102 is defined by a folded layer of epithelium 110 surrounded by stroma 112a. A layer of smooth muscle tissue 114 surrounds the stroma 112a. A layer of stroma 112b is between the muscle tissue 114 and connective tissue 124. Mucous glands 116, cartilage plates 118, blood vessels 120, and nerve fibers 122 are within the stroma layer 112b. Bronchial artery branches 130 and nerve trunks 45 are exterior to a wall 103 of the airway 100. The illustrated arteries 130 and nerve trunks 45 are within the connective tissue 124 surrounding the airway wall 103 and can be oriented generally parallel to the airway 100. In FIG. 1, for example, the nerve trunks 45 originate from the vagus nerves 41, 42 and extend along the airway 100 towards the air sacs. The nerve fibers 122 are in the airway wall 103 and extend from the nerve trunks 45 to the muscle tissue 114. Nervous system signals are transmitted from the nerve trunks 45 to the muscle 114 via the nerve fibers 122.
The instrument 310 can be delivered along the trachea, esophagus, or other body structure in the vicinity of the treatment site. For example, the instrument 310 can extend through one or more organs to position an energy emitter 314 proximate to the targeted tissue. Instruments 310, 312 can cooperate to treat the targeted tissue therebetween. The instrument 310 can cool interior regions of the airway wall 103 to cause the formation of the lesion 219 at the outer periphery of the airway wall 103. For radiofrequency ablation, the RF energy can travel between bipolar electrodes 314, 316. Tissue impedance causes heating that can reach sufficiently high temperatures to cause cell death. To protect non-targeted tissues (e.g., interior tissue), the instrument 310 can cool the airway to keep the nontargeted tissue below a temperature at which cell death occurs.
Thermal energy can be absorbed by the instrument 312 to keep the exterior regions of the airway wall 103 at or below a desired temperature. Both instruments 310, 312 can provide cooling to form lesions generally midway through the airway wall 103. The amount of energy delivered and cooling capacity provided by the instruments 310, 312 can be adjusted to shape and form lesions at different locations.
At least one of the instruments 310, 312 can be adapted to tunnel through tissue or between adjacent structures to allow it to reach the desired location, for example, along the bronchi. Additionally or alternatively, the instruments 310, 312 may be adapted to adhere to or slide smoothly along tissue or to be urged against a structure (e.g., trachea, esophagus, and/or bronchi) as the instrument is advanced.
FIG. 6 shows an instrument distal section 325 that includes a tissue-receiving region 324 and an energy emitter 326. The tissue-receiving region 324 has a concave surface 327 that generally matches a convex surface of an airway. A radius of curvature of the portion 324 can be approximately equal to the radius of curvature of the airway. When the distal section 325 is held against an airway, the energy emitter 326 can face targeted tissue.
FIG. 6A shows an instrument distal section 334 that includes an energy emitter 335 facing an airway 337. A distal tip 339 is shaped to keep the energy emitter 335 facing the airway 337 as the distal section 334 is moved distally, as indicated by an arrow 341. For example, the slope region 343 can help separate tissue 347 to facilitate distal movement of the distal section 334.
Referring to FIG. 7, an instrument distal section 330 includes a tissue-receiving surface 327 and an opposing guiding surface 329. The guiding surface 329 can slide smoothly along non-targeted tissue to facilitate advancement of the distal section 330. The curvature, contour, or slope of the guiding surface 329 can be selected to urge the tissue-receiving surface 327 against an anatomical structure. An energy emitter 342 (illustrated as a plurality of electrodes) can direct energy towards tissue received by the tissue-receiving surface 327. To position at least a portion of a nerve trunk in the surface 327, the tip 333 can be inserted between an airway and adjacent tissue.
A wide range of different types of guides can partially or completely surround a structure, such as the esophagus, trachea, or bronchus. Guides may include, without limitation, a plurality of arms (e.g., a pair of arms, a set of curved or straight arms, or the like), a ring (e.g., a split ring or a continuous ring), or the like. FIGS. 8, 8A, and 8B show embodiments of an instrument distal section 350 with a guide 352 capable of surrounding a generally tubular structure. An emitter 354 is positioned to deliver energy to a structure held by the guide 352. The distal section 350 can be moved along the airway using the guide 352. The guide 352 can be pulled off the airway and used to slide the distal section 350 along another airway or other anatomical structure.
The illustrated guide 352 is a split ring lying in an imaginary plane that is generally perpendicular to a longitudinal axis 361 of the distal section 350. To treat the main bronchus, resilient arms 353a, 353b can be moved away from each other to receive the bronchus. The arms 353a, 353b can snuggly hold the bronchus to allow atraumatic sliding. Surface 355a, 355b can slide smoothly along an airway or other body structure. In some embodiments, the guide 352 is pivotally coupled to the instrument shaft to allow the guide 352 to rotate as it moves along a structure.
FIG. 9 shows an instrument distal section 360 with guides in the form of openings 363. The openings 363 are circumferentially spaced about the periphery of a main body 365. A vacuum can be drawn through one or more of the openings 363 to hold the distal section 360 against tissue. In other embodiments, fluids can be delivered out of one or more of the openings 363 to push the distal section 360 in a desired direction.
FIG. 10 shows an instrument 400 with a distal section 412 wrapped around a left main bronchus. The distal section 412 can be configured to assume a helical shape or spiral shape. As shown in FIG. 11, energy emitters 414a-414n (collectively “414”) can deliver energy directly to the airway 100. An outer region 418 of the distal section 412 may not output energy to protect adjacent tissue. As such, the distal section 412 can effectively emit energy towards the airway 100. In other embodiments, the distal section 412 can output energy in all directions. A protective sleeve can be positioned over the applied distal section 412 to protect adjacent tissue. The sleeve can be made of an insulating material.
To treat the nerves 45, the electrodes 414c, 414j, 414k can be activated. The other electrodes 414 can remain inactive. In other embodiments, a continuous electrode can extend along the length of the distal section 414. The continuous electrode can be used to form a helical or spiral shaped lesion. In certain embodiments, the continuous electrode can have addressable sections to allow for selective ablation.
Airway cartilage rings or cartilage layers typically have a significantly larger electrical resistance than airway soft tissue (e.g., smooth muscle or connective tissue). Airway cartilage can impede the energy flow (e.g., electrical radiofrequency current flow) and makes the formation of therapeutic lesions to affect airway trunks challenging when the electrode is next to cartilage. The electrodes 414 can be positioned to avoid energy flow through cartilage. For example, the electrode 414 can be positioned between cartilage rings. Most or substantially all of the outputted energy can be delivered between the rings in some procedures. Tissue impedance can be measured to determine whether a particular electrode is positioned next to a cartilage ring, in an intercartilaginous space, or at another location.
Referring again to FIG. 10, the instrument 400 may have a lumen to receive a stylet to straighten and stiffen the preshaped distal section 412 during introduction. After insertion, the stylet can be withdrawn to allow the preshaped distal section 412 to assume a treatment configuration (e.g., a spiral configuration, a helical configuration, or the like). Alternatively, the distal section 412 may be relatively flexible and straight during introduction. A stylet having a shape corresponding to a desired shape may be inserted into the instrument 400 to impart the desired shape to the distal section 412. In a further embodiment, the instrument 400 may be shapeable or steerable using an actuator at its proximal end to allow it to be steered so as to surround the target tubular structure. Various steering mechanisms can be used, including, for example, one or more pull wires anchored to a distal tip at a point offset from the center line. The wire(s) can extend slidably through one or more lumens in the instrument 400 to the proximal end where they may be tensioned by an actuator so as to deflect the distal section 412.
FIG. 12 shows a system for non-invasively denervating a bronchial tree. An external energy source 500 is connected to an energy delivery system 510. The external energy source 500 can emit a beam of radiation to targeted tissue, such as nerve tissue. The beam of radiation can destroy the targeted tissue. The system can include, or be in the form of, a CyberKnife® Robotic Radiosurgery System from Accuray®, a TomoTherapy® radiation therapy system, or similar type of systems capable of targeting moving tissue, thereby mitigating or limiting damage to non-targeted tissue.
Beam radiation may be delivered from different remote locations to damage deep nerve tissue without damaging intervening tissues. The source of beam radiation may be a beam emitter 500 of an external beam radiotherapy system or a stereotactic radiation system 510. Because the lungs and bronchi move as the subject breathes, the system can be adapted to target moving tissues. By positioning the radiation beam emitter 500 at various locations relative to the patient's body 522, such systems may be used to deliver a radiation beam from various angles to the targeted nerve tissue. The dose of radiation given to intervening tissues may be insufficient to cause injury, but the total dose given to the target nerve tissue is high enough to damage (e.g., ablate) the targeted tissue.
Ultrasound can be used to damage targeted tissue. High intensity focused ultrasound may be used to target and damage the nerve tissue. The external energy source 500 can be a HIFU emission device. Alternatively, a catheter, an intra-luminal instrument, or other type of instrument for insertion into the body can include a HIFU emission device. By way of example, the element 209 of FIG. 3 can be a HIFU emission device. Such embodiments are well suited for delivery through another body structure, such as the esophagus or airway, to treat target tissue of an airway. The HIFU instrument may include ultrasound imaging capability to locate the targeted tissues. The HIFU instrument can emit a plurality of ultrasound “beams” from different angles toward the target tissues. The intensity of any one of the beams can be insufficient to damage intervening tissues. The beams can interfere at the target site and together have sufficient magnitude to damage the target nerve tissue.
The HIFU-based systems can be adapted to target moving tissues. For example, such systems may have a computer-controlled positioning system which receives input from an ultrasound or other imaging system and commands a positioning system in real time to maintain the HIFU device in a fixed position relative to the target structure.
Instruments disclosed herein may be entirely or partially controlled robotically or by a computer. Instruments may be attachable to a computer-controlled robotic manipulator which moves and steers the instruments. Robotic systems, such as the da Vinci® Surgical System from Intuitive Surgical or the Sensei Robotic Catheter system from Hansen Medical, Inc., or similar types of robotic systems, can be used. The instruments can have a proximal connector (e.g., an adaptor mechanism) that connects with a complementary fitting on the robotic system and links movable mechanisms of the instrument with control mechanisms in the robotic system. The instrument connector can also provide electrical couplings for wires leading to energy emitters, electrodes, microwave antennae, or other electrically powered devices. The instrument may further include sensor devices (e.g., temperature sensors, tissue impedance sensors, etc.) which are also coupled via the connector of the robotic system. The robotic system can include a control module that allows the physician to move and activate the denervation instrument while visualizing the location of the instrument within the chest, for example, using thoracoscopy, fluoroscopy, ultrasound, or other suitable visualization technology. The instrument may also be computer controlled, with or without robotic manipulation. A computer may receive feedback (e.g., sensory data) from sensors carried by the instrument or elsewhere to control positioning, power delivery, or other parameters of interest. For example, in energy-based denervation embodiments, a computer may be used to receive temperature data from temperature sensors of the instrument and to control power delivery to avoid overheating of tissue.
The instruments can access sites through blood vessels, as well as external to the organs. Robot surgery (including robotic catheter systems), natural orifice access methods, and minimally invasive access methods such as using trocar access methods and thoracoscopy have provided clinicians with access procedure locations within the human body and also minimized patient morbidity and complications due to surgery.
The assemblies, methods, and systems described herein can be used to affect tissue which is located on the outside of hollow organs, such as the lung, esophagus, nasal cavity, sinus, colon, vascular vessels and the like or other solid organs. Various types of activatable elements (e.g., energy emitters) can be utilized to output the energy. The activatable elements can be sufficiently small to facilitate percutaneous delivery to minimize or limit trauma to the patient.
The embodiments disclosed herein can treat the digestive system, nervous system, vascular system, or other systems. The treatment systems and its components disclosed herein can be used as an adjunct during another medical procedure, such as minimally invasive procedures, open procedures, semi-open procedures, or other surgical procedures (e.g., lung volume reduction surgery) that provide access to a desired target site. Various surgical procedures on the chest may provide access to lung tissue, the bronchial tree, or the like. Access techniques and procedures used to provide access to a target region can be performed by a surgeon and/or a robotic system. Those skilled in the art recognize that there are many different ways that a target region can be accessed. The various embodiments h such claims are entitled. Accordingly, the claims are not limited by the disclosure. described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments.
These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.

## Claims

1. A method for denervating a bronchial tree of a subject, comprising:
moving an energy emitter positioned at a distal section of an instrument through the subject's skin;
wrapping the distal section around an airway of the bronchial tree to position the energy emitter with respect to nerve tissue along the airway of the bronchial tree;
damaging the nerve tissue using energy from the energy emitter while the energy emitter is positioned outside of the airway; and
removing the instrument from the subject without severing the entire airway.

2. The method of claim 1, further comprising leaving the airway intact throughout the denervation process.

3. The method of claim 1, wherein damaging the nerve tissue comprises ablating a section of a nerve trunk to impede transmission of nervous system signals traveling along the airway.

4. The method of claim 1, further comprising delivering at least one of radiofrequency energy, microwave energy, radiation energy, high intensity focused ultrasound energy, and thermal energy to damage the nerve tissue.

5. The method of claim 1, further comprising:
percutaneously delivering the energy emitter proximate to the nerve tissue prior to damaging the nerve tissue.

6. The method of claim 1, further comprising:
moving an intraluminal instrument through the subject's trachea and the airway; and
delivering energy between the energy emitter of the instrument outside the airway and the intraluminal instrument positioned within the airway to ablate the nerve tissue.

7. The method of claim 1, wherein damaging the nerve tissue comprises irreversibly damaging nerve tissue between the subject's trachea and the subject's lung to at least partially block a transmission of nervous system signals and to cause a permanent decrease in smooth muscle tone of the portion of a bronchial tree.

8. The method of claim 1, wherein damaging the nerve tissue comprises ablating the nerve tissue without passing the instrument through a wall of the airway.

9. The method of claim 1, wherein damaging the nerve tissue comprises destroying the nerve tissue without substantially damaging blood vessels of the airway.

10. The method of claim 1, wherein the nerve tissue is positioned along a main bronchus of the bronchial tree.

11. The method of claim 1, further comprising visualizing the outside of the airway while positioning the energy emitter using a visualization device selected from a group consisting of a thoracoscope, an ultrasonic device, and a fluoroscopy system.

12. The method of claim 1 further comprising moving the energy emitter through a port, a cannula, or a sleeve extending through the skin.

13. A method comprising:
percutaneously delivering a distal section of an instrument through a subject's skin and wrapping the distal section of the instrument around an airway of a bronchial tree of the subject such that the distal section is positioned to damage nerve tissue of the bronchial tree; and
denervating a first portion of the bronchial tree using the instrument to substantially inhibit nervous system signals from traveling to a second portion of the bronchial tree.

14. The method of claim 13, further comprising damaging a nerve trunk positioned along a main bronchus.

15. The method of claim 13, wherein denervating comprises damaging nerve tissue positioned between the subject's trachea and lung.

16. The method of claim 13, wherein denervating the portion of the bronchial tree comprises ablating a sufficient amount of nerve tissue to prevent nervous system signals from traveling to substantially all bronchial branches of the bronchial tree.

17. The method of claim 13, further comprising denervating the first portion of the bronchial tree and removing the instrument without destroying the airway.

18. The method of claim 13, wherein the distal section of the instrument is positioned through a port, a cannula, or a sleeve extending through the subject's skin.

19. The method of claim 13, further comprising visualizing the outside of the airway while delivering the distal section using a visualization device selected from a group consisting of a thoracoscope, an ultrasonic device, and a fluoroscopy system.