WO1999003411A1

WO1999003411A1 - Method and apparatus for treatment of air way obstructions

Info

Publication number: WO1999003411A1
Application number: PCT/US1998/010747
Authority: WO
Inventors: Stuart D. Edwards; Ronald G. Lax
Original assignee: Somnus Medical Technologies, Inc.
Priority date: 1997-07-17
Filing date: 1998-05-27
Publication date: 1999-01-28
Also published as: AU7600898A

Abstract

A method for reducing a volume of a tongue includes providing an ablation apparatus with an energy delivery device configured to be coupled to an energy source. The energy delivery device is positioned in an interior of the tongue. A sufficient amount of energy is delivered from the energy delivery device in the interior of the tongue to ablate a section of the tongue without damaging the main branches of the hypoglossal nerve. The energy delivery device is thereafter removed from the interior of the tongue.

Description

METHOD AND APPARATUS FOR TREATMENT OF AIR WAY OBSTRUCTIONS

Cross-Reference to Related Applications This application is a continuation-in-part of U.S. Patent Application

Serial No. 08/606,195, filed February 23, 1996, which cross-references U.S. Patent Application No. 08/516,781 filed August 18, 1995, having named inventors Stuart D. Edwards, Edward J. Gough and David L. Douglass, which is a continuation-in-part of U.S. Application No. 08/239,658, filed May 9, 1994. All the above applications are assigned to the assignee of the instant application and are herein incorporated by reference.

BACKGROUND OF THE INVENTION

Field of the Invention This invention relates to a method for attaining patency of upper airway structures in human patients, and more particularly to a method which utilizes energy to debulk selected sections of the tongue and/or lingual tonsil without damaging the main branches of the hypoglossal nerve.

Description of Related Art

Sleep-apnea syndrome is a medical condition characterized by daytime hypersomnomulence, morning arm aches, intellectual deterioration, cardiac arrhythmias, snoring and thrashing during sleep. It is caused by frequent episodes of apnea during the patient's sleep. The syndrome is classically subdivided into two types. One type, termed "central sleep apnea syndrome", is characterized by repeated loss of respiratory effort. The second type, termed obstructive sleep apnea syndrome, is characterized by repeated apneic episodes during sleep resulting from obstruction of the patient's upper airway or that portion of the patient's respiratory tract which is cephalad to, and does not include, the larynx. Treatment thus far includes various medical, surgical and physical measures. Medical measures include the use of medications such as protriptyline, medroxyprogesterone, acetazolamide, theophylline, nicotine and other medications in addition to avoidance of central nervous system depressants such as sedatives or alcohol. The medical measures above are sometimes helpful but are rarely completely effective. Further, the medications frequently have undesirable side effects.

Physical measures have included weight loss to open the airway and use of nasal CPAP and various tongue retaining devices. These devices may be partially effective but are cumbersome, uncomfortable and patients often will not continue to use these for prolonged periods of time. Weight loss may be effective but is rarely maintained by these patients.

In patients with central sleep apnea syndrome, phrenic nerve or diaphragmatic pacing has been used. Phrenic nerve or diaphragmatic pacing includes the use of electrical stimulation to regulate and control the patient's diaphragm which is innervated bilaterally by the phrenic nerves to assist or support ventilation. This pacing is disclosed in Direct Diaphragm Stimulation by J. Mugica et al. PACE vol. 10 Jan-Feb. 1987, Part II, Preliminary Test of a Muscular Diaphragm Pacing System on Human Patients by J. Mugica et al. from Neurostimulation: An Overview 1985 pp. 263-279 and Electrical

Activation of Respiration by Nochomovitez IEEE Eng. in Medicine and Biology; June, 1993.

However, it was found that many of these patients also have some degree of obstructive sleep apnea which worsens when the inspiratory force is augmented by the pacer. The ventilation induced by the activation of the diaphragm also collapses the upper airway upon inspiration and draws the patient's tongue inferiorly down the throat choking the patient. These patients then require tracheostomies for adequate treatment.

A physiological laryngeal pacemaker as described in Physiological Laryngeal Pacemaker by F. Kaneko et al. from Trans Am Soc Artif Intern

Organs 1985 senses volume displaced by the lungs and stimulates the appropriate nerve to open the patient's glottis to treat dyspnea. This apparatus is not effective for treatment of sleep apnea. The apparatus produces a signal proportional in the displaced air volume of the lungs and thereby the signal produced is too late to be used as an indicator for the treatment of sleep apnea. There is often no displaced air volume in sleep apnea due to obstruction.

Surgical interventions have included uvulopalatopharyngoplasty, tonsillectomy, tracheostomy and surgery to correct severe retrognathia.

One measure that is effective in obstructive sleep apnea is tracheostomy. However, this surgical intervention carries considerable morbidity and is aesthetically unacceptable to many patients. Other surgical procedures include pulling the tongue as forward as possible and surgically cutting and removing sections of the tongue and other structures which can close off the upper airway passage.

There is a need for a method to treat airway obstruction disorders that decreases the volume of portions of the tongue without damaging the main branches of the hypoglossal nerve and with reduced surgical intervention.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide a method that reduces the volume of selected portions of the tongue without damaging the main branches of the hypoglossal nerve.

Another object of the invention is to provide a method that provides sufficient energy to ablate a portion of a interior of the tongue without damaging the main branches of the hypoglossal nerve. A further object of the invention is to provide a method that provides sufficient electromagnetic energy to ablate a portion of the interior of the tongue without damaging the main branches of the hypoglossal nerve resulting in a larger airway passage.

Yet another object of the invention is to provide a method for treating airway obstructions by ablating a portion of the interior of the tongue. Another object of the invention is to provide a method for treating airway obstructions by ablating a portion of the interior of the lingual tonsil.

These and other objects of the invention are achieved by providing an ablation apparatus including a source of energy and one or more energy delivery devices coupled to the energy source. At least one energy delivery device is advanced into an interior of the tongue. Energy is delivered from the energy delivery device to ablate a section of the tongue without damaging a main branch of the hypoglossal nerve. The energy delivery device is then removed from the interior of the tongue. One method for treating airway obstructions is achieved by ablating one or more interior sections of the tongue. This provides a larger airway passage. Another method for treating airway obstructions is achieved by ablating sections of the lingual tonsil.

The energy source can be any source of energy that can provide the ablation including but not limited to RF, microwave, coherent light and the like.

In one embodiment, at least one energy delivery device is introduced into the tongue and at least 1% of the tongue is debulked. One or more energy delivery devices can be advanced into the tongue through different surfaces of the tongue such as the tip, the ventral surface, the dorsum of the tongue or the interior dorsal surface.

In one embodiment, an introducer is provided with a lumen and the energy delivery devices are advanced out of the introducer into an interior of the tongue. The introducer may be malleable in order to conform to a the surface of a patient's tongue. Further, a distal end of the introducer can be deflectable. The introducer can include a temperature control element, including but not limited to a temperature control coupled to a source of temperature control medium. Optionally provided is an imaging apparatus such as an ultrasound apparatus. BRIEF DESCRIPTION OF THE FIGURES

Figures 1A-1C are cross-sectional views of an ablation apparatus used with the methods of the present invention.

Figure 2 is cross-sectional view illustrating the introducer and connector of the ablation apparatus shown in Figures lA-lC.

Figure 3 is a perspective view of the connector illustrated in Figures 1 A- 1C.

Figures 4A-4C are perspective views of a needle energy delivery device associated with the ablation apparatus illustrated in Figures 1 A-IC. Figure 5 is a perspective view of a flexible needle energy delivery device utilized with the methods of the present invention.

Figure 6 illustrates the creation of cell necrosis zones with the ablation apparatus shown in Figures lA-lC.

Figure 7 is a cross-sectional view of the tongue with the mouth closed. Figure 8 is a cross-sectional view of the tongue with the mouth open.

Figure 9 is a perspective view of the tongue. Figure 10 is a perspective view of the dorsum of the tongue. Figure 11 is a cross-sectional view of the tongue. Figure 12 is a cross-sectional view of the tongue illustrating the location of the main branches of the hypoglossal nerves and the creation of a cell necrosis zone.

Figure 13 is a cross-sectional view of the tongue illustrating a plurality of cell necrosis zones.

Figure 14 is a perspective view of the ventral surface of the tongue. Figure 15 is a cross-sectional view of the tongue.

Figure 16 is a block diagram of a feedback control system useful with the methods of the present invention.

Figure 17 is a block diagram illustrating an analog amplifier, analog multiplexer and microprocessor used with the feedback control system of Figure 16. DETAILED DESCRIPTION

A method for ablating an interior of the tongue, lingual tonsil and/or adenoids provides an ablation apparatus including a source of energy and one or more energy delivery devices coupled to the energy source. At least one energy delivery device is advanced into an interior of the tongue. Sufficient energy is delivered from the energy delivery device to ablate a section of the tongue without damaging the main branches of the hypoglossal nerve. For purposes of this disclosure, the main branches of the hypoglossal nerve are those branches which if damaged create an impairment, either partial or full, of speech or swallowing capabilities.

The energy delivery device is then removed from the interior of the tongue. A method for treating airway obstructions is achieved by ablating the tongue without damaging the main branches of the hypoglossal nerve.

The energy delivery device can be introduced into the tongue from the tongue's tip, ventral surface, dorsum, underneath the tongue, along the tongue's midline, or in certain instances through the chin area. An interior section of the tongue is ablated without damaging the main branches of the hypoglossal nerves. This is achieved by positioning the energy delivery device far enough away from the main branches of the hypoglossal nerve so that during the delivery of energy to the tongue, the main branches of the hypoglossal nerve are not damaged.

Another method for treating airway obstructions is achieved by ablating an interior section of the lingual tonsil. These methods are used to treat sleep apnea. Referring to Figures 1A-1C and 2, an ablation apparatus 10 for ablating the tongue, lingual tonsils, and/or adenoids is illustrated. Ablation apparatus 10 can be positioned so that one or more energy delivery devices 12 are introduced into an interior of the tongue. Ablation apparatus 10 may include atraumatic intubation with or without visualization, provide for the delivery of oxygen or anesthetics, and can be capable of suctioning blood or other secretions. It will be appreciated that ablation apparatus 10 is used to treat a variety of different obstructions in the body where passage of gas is restricted. One application is the treatment of sleep apnea using energy delivery devices 12 to ablate selected portions of the tongue, lingual tonsils and/or adenoids by the use of RF, microwave, ultrasound, coherent light, incoherent light, thermal transfer, resistive heating, chemical ablation, cryogenic fluid, electrolytic solutions, and the like.

Ablation apparatus 10 can be used to ablate tissue of anatomical structures. In one embodiment, ablation apparatus 10 is used to ablate an interior region of the tongue. For purposes of this disclosure an ablation shall mean debulk, shrunk, remodel, or to induce tissue scarring in order to increase the cross-sectional area of the airway passage. Hereafter the anatomical structure shall be referred to as the tongue. It will be appreciated that other anatomical structures including but are not limited to tonsils, turbinates, soft palate tissues, uvula, hard tissue and, in selected instances, mucosal tissue can be treated.

Prior to ablating the tongue, a presurgical evaluation may be performed including a physical examination, fiber optic pharyngoscopy, cephalometric analysis and polygraphic monitoring. The physical examination emphasizes the evaluation of the head and neck. It also includes a close examination of the nasal cavity to identify obstructing deformities of the septum and turbinate; oropharyngeal obstruction from a long, redundant soft palate or hypertrophic tonsils; and hypopharyngeal obstruction from a prominent base of the tongue. Ablation apparatus 10 includes an introducer 14, a handle 16, one or more energy delivery devices 12 extending from different ports formed along a longitudinal surface of introducer 14 or from its distal end 14', as well as an energy delivery device advancement and retraction device 18. Introducer 14 and handle 16 may be one device.

Energy delivery devices 12 may include a central lumen for receiving a variety of fluids that can be introduced into the interior an anatomical structure, as well as a plurality of fluid delivery ports. One suitable fluid is an electrolytic solution and another is a temperature control medium. Energy deliver can be direct from energy delivery device 12 to tissue, indirect fro energy delivery device 12 to electrolytic solution to tissue, or a combination of the two. Another suitable fluid is a temperature control fluid which controls a tongue surface temperature in the range of 10 - 45 degrees C.

An energy delivery surface of energy delivery device 12 can be adjusted by the inclusion of an adjustable or non-adjustable insulation sleeve 20 (Figures 3, 4A-4C and 5). Insulation sleeve 20 can be advanced and retracted along the exterior surface of energy delivery device 12 in order to increase or decrease the length of the electromagnetic energy delivery surface. Insulation sleeve 20 can be made of a variety of materials including but not limited to nylon, polyimides, other thermoplastics and the like. The amount of available electromagnetic energy delivery surface of energy delivery device 12 can be varied by other methods including but not limited to creating a segmented energy delivery device with a plurality of energy delivery devices that are capable of being multiplexed and individually activated, and the like.

Referring again to Figures 1A-1C, handle 16 is preferably made of thermal and electrical insulating material including but not limited to a thermoplastic such as polycarbonate, ABS, polypropylene, polyurethane, and the like. Examples of such suitable insulating materials include but are not limited to stainless steel, platinum, other noble metals and the like. Energy delivery devices 12 are made of a conductive material such as stainless steel. Additionally, energy delivery devices 12 can be made of a shaped memory metal, such as nickel titanium. It is possible that only a distal end of energy delivery device 12 is made of the shaped memory metal in order to effect a desired deflection.

For many applications it is desirable for a distal end 14' of introducer 14 to be conformable or deflectable. This can be achieved mechanically or with the use of memory metals. A steering wire, or other mechanical structure, may be attached to either the exterior or interior of distal end 14'. In one embodiment, a deflection knob located on handle 16 is activated by the physician causing a steering wire to tighten. This imparts a retraction of distal end 14', resulting in its deflection. It will be appreciated that other mechanical devices can be used in place of the steering wire. Deflection may be useful for tissue sites with difficult access. Introducer 14 can be malleable in order to conform to the surface of the tongue when a selected ablation target site is selected. A soft metal member may be enclosed or encapsulated within a flexible outer housing to form malleable introducer 14. An encapsulated soft metal, such as copper, or an annealed metal/plastic material can be used to form malleable introducer 14. All or a portion of introducer 14 may be malleable or made of a shaped memory metal. When a shaped memory metal is used introducer 14 is electrically insulated from energy delivery devices 12.

Introducer 14 may include a temperature control system, including but not limited to a temperature control channel 22 with a temperature control inlet 24 for receiving a temperature control medium such as water, and a temperature control outlet 26. Other methods for temperature control are suitable, including but not limited to a temperature control channel on an exterior surface of introducer 14. Temperature control is desirable to minimize adhesion of introducer 14 to the tongue, reduce the risk of an edematous response of the tongue and other body organs or structures, and to control the temperature of the ablation site. Controlling the temperature of the tongue reduces cell necrosis at the mucosal layer and preserves the taste buds.

Handle 16 can include a connector 28 coupled to retraction and advancement device 18. Connector 28 provides a coupling of energy delivery devices 12 to power, feedback control, temperature and/or imaging systems. An

RF/temperature control block 30 can be included (Figure 3).

In one embodiment, the physician moves retraction and advancement device 18 in a direction toward a distal end of connector 28. Energy delivery devices 12 can be spring loaded. When retraction and advancement device is moved back, springs cause selected energy delivery devices 12 to advance out of introducer 14. Energy delivery devices 12 can be deployed in a lateral direction relative to a longitudinal axis of introducer 14, out of introducer distal end 14', and the like.

One or more cables 32 couple energy delivery devices 12 to an energy source 34. A variety of energy sources 34 can be used with the present invention to transfer thermal energy to the tissue site, including but not limited to RF, microwave, ultrasonic, coherent light, incoherent light, thermal transfer, resistive heating, chemical ablation, cryogenic fluid, electrolytic solutions and the like. Preferably, energy source 34 is an RF generator. When an RF energy source is used, the physician can activate RF energy source 34 by the use of a foot switch (not shown) coupled to RF energy source 34. Energy delivery device 12 may be a needle electrode. One or more sensors 36 may be used to measure temperature. For purposes of this specification sensors which are not introduced into an interior of a body structure are denoted as 36. Sensors which are introduced into the body structure are denoted as 36'. One or more sensors 36 and 36' may be positioned on an interior or exterior surface of energy delivery device 12, insulation sleeve 20, or be independently inserted into the tissue site separably from ablation apparatus 10. Sensors 36 and 36' permit accurate measurement of temperature at a tissue site and if a predetermined maximum temperature is exceeded, the energy power supply/controller will reduce or shut down the power being delivered. By monitoring the temperature and modulating the energy delivered, sensors 36 and 36' prevent non-targeted tissue from being destroyed or ablated.

Sensors 36 and 36' are of conventional design, including but not limited to thermistors, thermocouples, resistive wires, and the like. Suitable sensors 36 include a T type thermocouple with copper constantan, J type, E type, K type, fiber optics, resistive wires, thermocouple IR detectors, and the like. It will be appreciated that sensors 36 and 36' need not be thermal sensors.

Sensors 36' can measure temperature at various points within the interior of the body structure. The data collected may be used to determine the temperature attained and by comparing the rate of rise against time, power level and impedance, the size and extent of lesion may be computed. If at any time sensor 36 or 36' determines that a desired temperature is exceeded, then an appropriate feedback signal is received at energy source 34 and the amount of energy delivered is regulated.

Ablation apparatus 10 can include visualization capability including but not limited to a viewing scope, ultrasound, an expanded eyepiece, fiber optics, video imaging, and the like.

Additionally, an ultrasound transducer 38 determines the size and position of the created lesion. In one embodiment, two ultrasound transducers are positioned on opposite sides of introducer 14 to create an image depicting the lesion in the tongue. Each ultrasound transducer 38 is coupled to an ultrasound source (not shown).

In one embodiment, ultrasound transducer 38 is a piezoelectric crystal mounted on a backing material. The piezoelectric crystal is connected by electrical leads to the ultrasound source. Ultrasound transducers 38 transmit ultrasound energy into adjacent tissue, including but not limited to the tongue.

With reference now to Figure 6 introducer 14 is shown as being introduced into the oral cavity and multiple energy delivery devices 12 are advanced into the interior of the tongue creating different ablation zones 40. Ablation apparatus can be operated in either bipolar or monopolar modes (with a ground pad). When energy delivery device 12 is an RF electrode, the electrodes 12 are operated in either mode to create ablation zones 40 in the tongue without damaging the main branches of the hypoglossal nerve. A larger airway passage is created. For purposes of this specification, the main branches of the hypoglossal nerve are those branches which if damaged create an impairment, either partial or full, of speech or swallowing capabilities. Creation of the ablation zone in the tongue may result in a shrinkage of tissue, a reshaping of the posterior surface of the tongue, and/or a debulking of the tongue.

In one embodiment, a single energy delivery device 12 is positioned in the tongue to create a first ablation zone 40. Energy delivery device 12 can then be retracted from the interior of the tongue, introducer 14 moved, and energy delivery device 12 is then advanced from introducer 14 into another interior section of the tongue. A second ablation 40 is created. This procedure can be completed any number of times to form different ablation regions in the interior of the tongue. Energy delivery devices 12 are then repositioned in the interior of the tongue any number of times to create a plurality of connecting or non- connecting ablation zones 40 in either bipolar or monopolar modes.

Referring now to Figures 7 through 15, various anatomical views of the tongue and other structures are illustrated. The different anatomical structures are as follows: the genioglossus muscle, or body of the tongue is denoted as 42; the geniohyoid muscle is 44; the mylohyoid muscle is 46; the hyoid bone is 48; the tip of the tongue is 50; the ventral surface of tongue is denoted as 52; the dorsum of the tongue is denoted as 54; the inferior dorsal of the tongue is denoted as 56; the reflex of the vallecula is 58; the lingual follicles are denoted as 60; the uvula is 62; the adenoid area is 64; the lateral border of the tongue is 66; the circumvallate papilla is 68, the palatine tonsil is 70; the pharynx is 72; the redundant pharyngeal tissue is 74; the foramen cecum is 76; the main branches of the hypoglossal nerve are 78, and the lingual frenum of the tongue is 80.

Dorsum 54 is divided into anterior 2/3 and inferior dorsal 56. The delineation is determined by circumvallate papilla 68 and foramen cecum 76.

Inferior dorsal 56 is the dorsal surface inferior to circumvallate papilla 68 and superior reflex of the vallecula 58. Reflex of the vallecula 58 is the deepest portion of the surface of the tongue contiguous with the epiglottis. Lingual follicles 60 comprise the lingual tonsil. Energy delivery devices 12 can be inserted into an interior of tongue 42 through dorsum surface 54, inferior dorsal surface 56, ventral surface 52, tip 50 or geniohyoid muscle 44. Additionally, energy delivery devices may be introduced into an interior of lingual follicles 60 and into adenoid area 64.

In all instances, the positioning of energy delivery devices 12, as well as the creation of ablation zones 40 is such that the main branches of the hypoglossal nerve 78 are not ablated or damaged. The ability to swallow or speak is not impaired. This creates a larger air passageway and provides a treatment for sleep apnea.

Referring now to Figure 16, an open or closed loop feedback system couples sensors 36 or 36' to energy source 34. In this embodiment, energy delivery device 12 is one or more RF electrodes. It will be appreciated that other energy delivery devices 12 can also be used with the feedback system.

The temperature of the tissue, or of RF electrode 12 is monitored, and the output power of energy source 34 adjusted accordingly. The physician can, if desired, override the closed or open loop system. A microprocessor can be included and incorporated in the closed or open loop system to switch power on and off, as well as modulate the power. The closed loop system utilizes microprocessor 82 to serve as a controller, monitor the temperature, adjust the RF power, analyze at the result, refeed the result, and then modulates the power. With the use of sensors 36' and the feedback control system a tissue adjacent to RF electrode 12 can be maintained at a desired temperature for a selected period of time without impeding out. Each RF electrode 12 is connected to resources which generate an independent output. The output maintains a selected energy at RF electrodes 12 for a selected length of time. Current delivered through RF electrodes 12 is measured by current sensor 84. Voltage is measured by voltage sensor 86. Impedance and power are then calculated at power and impedance calculation device 88. These values can then be displayed at user interface and display 90. Signals representative of power and impedance values are received by a controller 92.

A control signal is generated by controller 92 that is proportional to the difference between an actual measured value, and a desired value. The control signal is used by power circuits 94 to adjust the power output in an appropriate amount in order to maintain the desired power delivered at respective RF electrodes 12.

In a similar manner, temperatures detected at sensors 36' provide feedback for maintaining a selected power. Temperature at sensors 36 are used as safety devices to interrupt the delivery of energy when maximum pre-set temperatures are exceeded. The actual temperatures are measured at temperature measurement device 96, and the temperatures are displayed at user interface and display 90. A control signal is generated by controller 92 that is proportional to the difference between an actual measured temperature and a desired temperature. The control signal is used by power circuits 94 to adjust the power output in an appropriate amount in order to maintain the desired temperature delivered at the respective sensors 36 or 36'. A multiplexer can be included to measure current, voltage and temperature, at the numerous sensors 36 and 36', and energy can be delivered to RF electrodes 12 in monopolar or bipolar fashion.

Controller 92 can be a digital or analog controller, or a computer with software. When controller 92 is a computer it can include a CPU coupled through a system bus. On this system can be a keyboard, a disk drive, or other non-volatile memory systems, a display, and other peripherals, as are known in the art. Also coupled to the bus are a program memory and a data memory.

User interface and display 90 includes operator controls and a display. Controller 92 can be coupled to imaging systems, including but not limited to ultrasound, CT scanners, X-ray, MRI, mammographic X-ray and the like. Further, direct visualization and tactile imaging can be utilized. The output of current sensor 84 and voltage sensor 86 is used by controller 92 to maintain a selected power level at RF electrodes 12. The amount of RF energy delivered controls the amount of power. A profile of power delivered can be incorporated in controller 92 and a preset amount of energy to be delivered can also be profiled. Circuitry, software and feedback to controller 92 result in process control, and the maintenance of the selected power setting that is independent of changes in voltage or current, and used to change, (i) the selected power setting, (ii) the duty cycle (on-off time), (iii) bipolar or monopolar energy delivery and (iv) fluid delivery, including flow rate and pressure. These process variables are controlled and varied, while maintaining the desired delivery of power independent of changes in voltage or current, based on temperatures monitored at sensors 36 or 36'.

Referring to Figure 17, current sensor 84 and voltage sensor 86 are connected to the input of an analog amplifier 98. Analog amplifier 98 can be a conventional differential amplifier circuit for use with sensors 36 and 36'. The output of analog amplifier 98 is sequentially connected by an analog multiplexer 100 to the input of A/D converter 102. The output of analog amplifier 98 is a voltage which represents the respective sensed temperatures. Digitized amplifier output voltages are supplied by A/D converter 102 to microprocessor 82. Microprocessor 82 may be a type 68HCII available from Motorola.

However, it will be appreciated that any suitable microprocessor or general purpose digital or analog computer can be used to calculate impedance or temperature.

Microprocessor 82 sequentially receives and stores digital representations of impedance and temperature. Each digital value received by microprocessor 82 corresponds to different temperatures and impedances. Calculated power and impedance values can be indicated on user interface and display 90. Alternatively, or in addition to the numerical indication of power or impedance, calculated impedance and power values can be compared by microprocessor 82 with power and impedance limits. When the values exceed predetermined power or impedance values, a warning can be given on user interface and display 90, and additionally, the delivery of RF energy can be reduced, modified or interrupted. A control signal from microprocessor 82 can modify the power level supplied by energy source 34. The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. It is intended that the scope of the invention be defined by the following claims and their equivalents.

What is claimed is:

Claims

1. A method for reducing a volume of a tongue, comprising: providing a ablation apparatus including an energy delivery device configured to be coupled to an energy source; positioning at least one energy delivery device into an interior of the tongue; delivering a sufficient amount of energy from the energy delivery device into the interior of the tongue to ablate a section of the tongue without damaging the main branches of the hypoglossal nerve; and removing the energy delivery device from the interior of the tongue.

2. The method of claim 1 , wherein the energy source is an RF source.

3. The method of claim 1, wherein the energy source is a microwave source.

4. The method of claim 1, wherein the energy delivery device is positioned in an interior of the tongue through a ventral surface of the tongue.

5. The method of claim 1, wherein the energy delivery device is positioned in an interior of the tongue through an inferior dorsal surface of the tongue.

6. The method of claim 1, wherein the energy delivery device is positioned in an interior of the tongue through a dorsum surface of the tongue.

7. The method of claim 1, wherein the energy delivery device is positioned in an interior of the tongue through a tip of the tongue.

8. The method of claim 1 , wherein two or more energy delivery devices are positioned in a different interior area of the tongue.

9. The method of claim 1 , wherein two or more energy delivery devices are introduced through a different surface site of the tongue.

10. The method of claim 1 , wherein the ablation apparatus further comprises: a introducer including a lumen, wherein the energy delivery device is deployed from the introducer lumen into an interior of the tongue.

11. The method of claim 1 , wherein the introducer further comprises: a temperature control device.

12. The method of claim 11, wherein the temperature control device comprises a cooling channel in an interior of the introducer, the cooling channel receiving a cooling medium and circulating the cooling medium through the interior of the introducer.

13. The method of claim 12, further comprising: cooling a surface of the tongue while an energy delivery device ablates an interior section of the tongue.

14. The method of claim 10, wherein the introducer is introduced into an oral cavity and one or more energy delivery devices are introduced in an interior of the tongue through one of an inferior dorsal surface of the tongue, a dorsum surface of the tongue, or a tip of the tongue.

15. The method of claim 10, wherein the introducer is introduced into an oral cavity and one or more energy delivery devices are introduced in an interior of the tongue through a ventral surface of the tongue.

16. The method of claim 1, further comprising: providing an imaging apparatus.

17. The method of claim 16, wherein the imaging apparatus is an ultrasound device.

18. The method of claim 16, further comprising: imaging the tongue prior to ablating the tongue.

19. The method of claim 16, further comprising: imaging the tongue after ablating the tongue.

20. A method for treating airway obstructions, comprising: providing an ablation apparatus including an energy delivery device configured to be coupled to an energy source; positioning at least a portion of the energy delivery device in an interior of a tongue; delivering sufficient energy from the energy delivery device into the interior of the tongue to ablate an interior section without damaging a main branch of the hypoglossal nerve; and removing the energy delivery device from the interior of the tongue.

21. The method of claim 20, wherein the energy delivery device is positioned in an interior of the tongue through a ventral surface of the tongue.

22. The method of claim 20, wherein the energy delivery device is positioned in an interior of the tongue through an inferior dorsal surface of the tongue.

23. The method of claim 20, wherein the energy delivery device is positioned in an interior of the tongue through a dorsum surface of the tongue.

24. The method of claim 20, wherein the energy delivery device is positioned in an interior of the tongue through a tip of the tongue.

25. The method of claim 20, wherein the ablation apparatus further comprises: a introducer including a lumen, wherein the energy delivery device is deployed from the introducer lumen into an interior of the tongue.

26. The method of claim 25, wherein the introducer is introduced into an oral cavity and one or more energy delivery devices are introduced in an interior of the tongue through one of an inferior dorsal surface of the tongue, a dorsum surface of the tongue, or a tip of the tongue.

27. The method of claim 25, wherein the introducer is introduced into an oral cavity and one or more energy delivery devices are introduced in an interior of the tongue through a ventral surface of the tongue.

28. The method of claim 20, wherein the energy source is an RF source.

29. The method of claim 20, wherein the tongue is ablated sufficiently to increase a cross-sectional area of the airway passage.

30. The method of claim 20, further comprising: providing an imaging apparatus.

31. The method of claim 30, further comprising: imaging the tongue prior to ablation.

32. The method of claim 30, further comprising: imaging the tongue after ablation.

33. A method for treating airway obstructions, comprising: providing an ablation apparatus including an energy delivery device coupled to an energy source; delivering sufficient energy from the energy delivery device in an interior of the lingual tonsil and ablate the lingual tonsil; and removing the energy delivery device from the lingual tonsil.

34. The method of claim 33, wherein the energy source is an RF source.

35. The method of claim 33, wherein one or more energy delivery devices are positioned in a different section of the lingual tonsil.

36. The method of claim 33, further comprising: providing an imaging apparatus.

37. The method of claim 36, wherein the imaging apparatus is an ultrasound device.

38. The method of claim 36, further comprising: imaging the lingual tonsil prior to ablation.

39. The method of claim 36, further comprising: imaging the lingual tonsil after ablation.

40. A method for reducing a volume of a tongue, comprising: providing an ablation apparatus including one or more RF electrodes coupled to an RF energy source; positioning at least one energy delivery device in an interior of the tongue; delivering RF energy from the energy delivery device in the interior of the tongue; and ablating a section in the interior of the tongue without damaging a hypoglossal nerve.

41. A method for treating airway obstructions, comprising: providing an ablation apparatus including one or more RF electrodes coupled to an RF energy source; positioning at least one energy delivery device in an interior of a tongue; delivering RF energy from the energy delivery device in the interior of the tongue; and creating cell necrosis in the interior of the tongue without damaging a hypoglossal nerve.

42. A method for treating airway obstructions, comprising: providing an ablation apparatus including one or more RF electrodes coupled to an RF energy; positioning at least one energy delivery device in an interior of a lingual tonsil; delivering sufficient RF energy from the energy delivery device in an interior of the lingual tonsil; creating cell necrosis in the interior of the lingual tonsil.