Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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APPARATUS FOR COSMFrlCALLY REMODELlNG A BODY STRUCI-URE
P~ACK~TROUNr) OF T~F INVFl~TION
Field of the Tnv~ntion
This invention relates to a method for "~ ini"g upper airway patency
in human patients, and more particularly to a method which utilizes
electromagnetic energy to debulk selected sections of the tongue and/or lingual
tonsil without d~m~gin~ the hypoglossal nerve.
nescr~tion of R~l~t~tl 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
plot~ lyline~ medroxyprogesterone, acetazolamide, theophylline, nicotine and
other medications in addition to avoidance of central nervous system depressallls
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.
Surgical interventions have included uvulopalatopharyngoplasty,
tonsillectomy, surgery to correct severe retrognathia and tracheostomy. In one
procedure the jaw is dislodged and pulled forward, in order to gain access to the
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base of the tongue. These procedures may be effective but the risk of surgery inthese patients can be prohibitive and the procedures are o~en unacceptable to
the patients.
Physical measures have included weight loss, nasopharyngeal airways,
nasal CPAP and various tongue ret~ining devices used nocturnally. These
measures 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 achieved 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 stim~ tion 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 Diaphragnt Stimulatio~1
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 Neurostimlll~tion: An Overview 1985 pp. 263-279 and Elec~rical
Activation of Respiration by Nochomovitez EEE 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 air~,vay upon h~syil ~lion and draws the
patient's tongue inferiorly down the throat choking the patient. These patients
then require tracheostomies for adequate tre~tm~nt
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 stim~ tes the
appropriate nerve to open the patient's glottis to treat dyspnea. This apparatus is
not effective for tre~tment of sleep apnea. The apparatus produces a signal
proportional in the displaced air volume of the lungs and thereby the signal
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produced is too late to be used as an indicator for the treatmçnt of sleep apnea.
There is often no displaced air volume in sleep apnea due to obstruction.
One measure that is effective in obstructive sleep apnea is tracheostomy.
However, this surgical intervention carries considerable morbidity and is
S 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 offthe upper airway
passage.
There is a need for a method and app~ s to overcome these problems.
SUMI~A~Y OF THE INVF.NTION
Accordingly, an object of the invention is to provide an appa~ s to
reduce a volume of a selected site in an interior of the tongue.
Another object of the invention is to provide an apparatus to reduce a
volume of a selected site in an interior of the tongue including an electrode and
an electrode advancement device, wherein the electrode advancement member
advances the electrode an advancement distance in the interior of the tongue
sufficient for an electrode electrom~gnetic energy delivery surface to deliver
electromagnetic energy to the selected tissue site and reduce a volume of the
selected site without d~m~gine a hypoglossal nerve.
Yet another object of the invention is to provide an appa- ~us to reduce a
volume of a selected site in an interior of the tongue inçhl~ing an electrode and
an electrode adv~nc~ment member, wherein the electrode advancement member
advances the electrode to a pl~cçm~.nt position in the interior of the tongue sothat at the pl~cçm~nt position an electrode electromagnetic energy delivery
surface can deliver sufficient electromagnetic energy to reduce a volume of the
selected site without d~m~ging a hypoglossal nerve.
A further object of the invention is to provide an apparatus to reduce a
volume of a selected site in an interior of the tongue with an electrode, an
electrode electromagnetic energy delivery surface and an electrode advancement
length e~tP.n(ling from an exterior of a handpiece to the interior of the tongue,
.
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wherein the advanccment length is sufficient to position the electrode
electromagnetic energy delivery surface at the selected site and deliver sufficient
electromagnetic energy to reduce a volume of the selected tissue site without
d~m~ging a hypoglossal nerve.
Still a further object of the invention is to provide an appalal-ls to reduce
a volume of a selected site in an interior of the tongue that includes an electrode
with a geometric shape configured to reduce a volume of the selected site
without d~m~ging a hypoglossal nerve.
These and other objects of the invention are achieved in an apparatus that
reduces a volume of a selected site in an interior of the tongue. The apparatus
includes a handpiece and an electrode at least partially positioned in the interior
of the catheter. The electrode includes an electrode electromagnetic energy
delivery surface and is advance able from the interior of the handpiece into theinterior of the tongue. An electrode advancement member is coupled to the
electrode and configured to advance the electrode an advancement distance in
the interior of the tongue. The advancement distance is sufficient for the
electrode electromagnetic energy delivery surface to deliver electrom~gn.otic
energy to the selected tissue site and reduce a volume of the selected site
without d~m~ging a hypoglossal nerve and/or a surface of the tongue. A cable is
coupled to the electrode.
In another embodiment, the electrode advancement member is configured
to advance at least a portion of the electrode to a placement position in the
interior of the tongue. At the placement position the electrode electromagnetic
energy delivery surface delivers sufficient electromagnetic energy to reduce a
volume of the selected site without ~m~ing a hypoglossal nerve.
In a further embodiment, the electrode has an electrode advancement
length that extends from an exterior of the catheter to the interior of the tongue.
The advancement length is sufficient to position the electrode electromagnetic
energy delivery surface at the selected site and deliver sufficient electromagnetic
energy to reduce a volume of the selected tissue site without tl~m~ging a
hypoglossal nerve.
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The electrode is preferably an RF electrode coupled to an RF energy
source. A cooling device can be included that is at least partially positioned in
the interior of the catheter and configured to cool a selected surface of the
tongue. A flow rate control device may be coupled to the cooling device to
control a cooling medillm flow rate through the cooling device.
An insulator is at least partially positioned around an exterior of the
electrode and defines the electromagnetic energy delivery surface of the
electrode. Sensors can be positioned at various locations inclu~ling, at a distal
end of the insulator, at the distal end of the electrode and on an exterior surface
of the catheter.
In one embodiment, a first sensor is positioned at the distal end of the
electrode and a second sensor positioned at the distal end of an insulator.
A feedback control device can be coupled to the electrode, the sensors
and an electromagnetic energy source. Additionally, an infusion medil]m source
may be coupled to the electrode.
P~RTF.F nF..~CR~PTION OF THF. FIGURFS
Figure 1 is a cross-sectional view of an ablation appa~ s used with the
methods of the present invention.
Figure 2 is cross-sectional view illustrating the catheter and connector of
the ablation appa~a~-ls shown in Figure 1.
Figure 3 is a perspective view of the connector illustrated in Figure 1.
Figure 4 is a perspective view of a needle electrode associated with the
ablation apparatus illustrated in Figure 1.
Figure 5 is a perspective view of a flexible needle electrode utilized with
the methods of the present invention.
Figure 6 illustrates the creation of ablation zones with the ablation
appal~t~ls shown in Figure 1.
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 ofthe tongue.
.
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Figure 10 is a perspective view ofthe dorsum ofthe 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 hypoglossal nerves and the creation of an ablation zone.
Figure 13 is a cross-sectional view of the tongue illustrating a plurality of
ablation 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 illustrating an analog amplifier, analog
multiplexer and microprocessor used with the feedback control system.
Figure 17 is a block diagram of a temperature/impedance feedback
system that can be used to control cooling medium flow rate through the
catheter of Figure 1.
Figure 18 is a block diagram of a temperature/impedance feedback
1 S system that can be used to control cooling me(lium flow rate through the
catheter of Figure 1.
Figure 19 is a three dimensional graph illustrating the percent shrinkage
of the tongue following RF ablation.
Figure 20 is a graph illustrating two-dimensional shrinkage of bovine
tongue tissue with RF ablation.
Figure 21 is a graph illustrating three-dimensional shrinkage of bovine
tongue tissue due to RF ablation.
Figure 22 is a graph illustrating percent volume change in a tongue
following RF ablation.
I~ETATT Fn DESCR~PTION
A method for cosmetically remodeling and debulking the tongue, uvula,
soft palate, lingual tonsil and/or adenoids provides an ablation apparatus
including a source of electromagnetic energy and one or more electromagnetic
energy delivery electrodes coupled to the electrom~gnetic energy source. At
least one electrode is advanced into an interior of the tongue. Sufflcient
., ,
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electromagnetic energy is delivered from the electrode to debulk a section of the
tongue without d~m~ging the hypoglossal nerve. The electrode is then removed
from the interior of the tongue. A method for treating airway obstructions is
achieved by debulking the tongue without d~m~ging the hypoglossal nerve. The
electrode can be introduced into the tongue from the tongue's tip, ventral
surface, dorsum, underneath the tongue, along the tongue's mi~lin~, or in certain
instances through the chin area. The tongue is ablated (debulked) without
~m~ging the hypoglossal nerves, resulting in a remodeling of the tongue and a
cosmetic change. This is achieved by positioning the electrodes far enough away
from the hypoglossal nerves so that during the delivery of electromagnetic
energy to the tongue, the hypoglossal nerves are not damaged. Another method
for treating airway obstructions is achieved by debulking the lingual tonsil
without d~m~gin~ the hypoglossal nerve. These methods are used to treat sleep
apnea.
Referring to Figures 1 and 2, an ablation apparatus 10 for cosmetically
remodeling and debulking the tongue, lingual tonsils, uvula, soft palate and/or
adenoids is illustrated. Ablation apparatus 10 can be positioned so that one or
more energy delivery devices or electrodes 12 are introduced into an interior ofthe tongue through the tongue. Ablation appaldlLIs 10 may include atraumatic
intubation with or without vi~u~ tion, provide for the delivery of oxygen or
anesthetics, and can be capable of s~uctioning blood or other secretions. It will be
appreciated that ablation apparatus 10 is used to treat a variety of di~. t;n~
obstructions in the body where passage of gas is restricted. One embodiment is
the treatment of sleep apnea using electrodes 12 to ablate (cell necrosis) selected
portions of the tongue, lingual tonsils and/or adenoids by the use of resistive
heating, RF, microwave, ultrasound and liquid therrnal jet. The prt;r~ d energy
source is an RF source. In this regard, ablation apparatus 10 can be used to
ablate targeted masses inr,lutling but not limited to the tongue, tonsils, turbinates,
soft palate tissues, hard tissue and mucosal tissue. In one embodiment, ablationapp~ s 10 is used to debulk the tongue in order to increase the cross-sectional
area ofthe air passageway. A ~icinfect~nt mçdillm introduction member
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introduces a disinfectant medium in the oral cavity in order to reduce infection of
the ablated body member
Prior to debulking the tongue, a presurgical evaluation may be performed
including a physical ~ ;on, fiberoptic pharyngoscopy, cephalometric
analysis and polygraphic monitoring. The physical ex~min~tion emphasizes the
evaluation ofthe head and neck. It also includes a close ~ , llin~l ion ofthe nasal
cavity to identify obstructing deformities of the septum and turbinate;
oropharyngeal obstruction from a long, redlln~l~nt soft palate or hypertrophic
tonsils; and hypopharyngeal obstruction from a prominent base of the tongue.
Debulking appal~t~ls 10 includes a catheter 14, an optional handle 16 and
one or more electrodes 12 extending from dirrerenL ports 18 formed along a
longitllclin~l surface of catheter 14, or from a distal end of electrode 12.
Catheter 14 can be a handpiece. An advancement device 20 may be provided.
Advancement device 20 can include guide tracks or tubes 23 positioned in the
interior of c~theter 14. Electrodes 12 may be positioned in guide tracks 23 and
advanced from guide tracks into the interior of the tongue.
Ablation or debulking appal~L~Is 10 includes a catheter 14, an optional
handle 16 and one or more ablation source delivery device 12 e~tçn~ing from
different ports 18 formed along a longit~ldin:~l surface of catheter 14, or from a
distal portion of ablation source delivery device 12 Catheter 14 can be a
handpiece. Ablation source delivery device advancement device 20, also known
as advancement device 20 may be provided. Ablation source delivery device
advancement device 20 can include guide tracks or tubes 23 positioned in the
interior of catheter 14. Ablation source delivery device 12 may be positioned in2~ guide tracks 23 and advanced from the guide tracks into the interior ofthe
tongue. Cabling is coupled to ablation source delivery device 12.
Ablation source delivery device 12 may be least partially positioned in an
interior of catheter 14. In one embodiment, ablation source delivery device 12 is
advanced and retracted through a port 18 formed in an exterior surface of
catheter 14. Ablation source delivery device advancement and retraction device
20 advances ablation source delivery device 12 out of catheter 14, into an
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interior of a body structure and can also provide a retraction of ablation source
delivery device 12 from the interior of the body structure. Although the body
structure can be any number of di~elell~ structures, the body structure will
hereafter be referred to as the tongue. Ablation source delivery device 12 pierce
an exterior surface of the tongue and are directed to an interior region of the
tongue. Suff1cient ablation energy is delivered by ablation source 12 to the
interior of the tongue to cause the tongue to become sufficiently ablated and
debulked. Ablation source delivery device 12 can be a hollow structure that is,
(i) adapted to deliver di~elenl chemicals to a selected tongue interior ablationsite (for chemical ablation) (ii) deliver alcohol or other liquids or semi-liquids to
achieve ablation as well as a variety of di~erenl infusion mediums, including but
not limited to saline, chemotherapy and the like. Different modalities can be
combined to achieved a desired ablation including but not limited to RF and
chemotherapy, chemical and chemothel~py. Ablation source delivery device 12
may have a limited travel distance in the tongue. In one embodiment with RF
electrodes, this is achieved with an insulation sleeve that is in a surrounding
relationship to an exterior of an electrode. Other devices can include a structure
located on ablation source delivery device 12 which limits their advancement, ora structure coupled to a catheter which limits the advancement of ablation source
delivery devices 12, such as a stop and the like. One suitable fluid is an
electrolytic solution. Instead of direct contact with tissue and electrode 12 for
the delivery of thermal energy, a cooled electrolytic solution can be used to
deliver the thermal energy to the tissue. The electrolytic solution may be cooled
in the range of about 30 to 55 degrees C.
Catheter 14 incl~ldes a catheter tissue interface surface 22, a cooling
me~ m inlet conduit 24 and a cooling me~ lm exit conduit 26 ext~.n~ing
through an interior of catheter 14. Ports 18 are formed in the exterior of
catheter 14, and are preferably formed on catheter tissue interface surface 22.
Ports 18 are isolated from a cooling medillm flowing in inlet and outlet conduits
24 and 26. Cooling medium inlet and exit conduits 24 and 26 are configured to
provide a cooled section of catheter tissue interface surface 22 of at least 1 to 2
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cm2. More p,e~el~bly, the cooled section of catheter tissue interface surface 22is at least equal to the cross-sectional diameter of the underlying zone of
ablation.
In one embodiment, the cooled section of catheter tissue interface surface
22 is at least e~ual to the cross-sectional diameter of the underlying zone of
ablation. In another embodiment, the cooled section of catheter tissue interfacesurface 22 only provides cooling to an area associated with each deployed
ablation source delivery device.
The size of the cooled section of catheter tissue interface surface 22
varies for each patient. The size is sufficient enough to ~ i"~;~e swelling ofthe
tongue following the delivery of electromagnetic energy. The reduction of
swelling can be 50% or greater, 7~% or greater, and 90% and greater. The
amount of cooling provided is sufficient to enable the patient to return home
shortly after the debulking procedure is performed, and not run the risk of
choking on the tongue. It has been found that by providing a sufficient level ofcooling over a relatively large area, the amount of ablation in an interior region
of the tongue is enhanced. By providing a sufficiently large enough cooled
section of catheter tissue interface surface 22, an adenomas response is
.
Illil~illl-7~
Handle 16 is preferably made of an in.~ ting material. Electrodes 12 are
made of a conductive material such as stainless steel. Additionally, electrodes 12
can be made of a shaped memory metal, such as nickel tit~nil~m, commercially
available from Raychem Corporation, Menlo Park, California. In one
embodiment, only a distal end of electrode 12 is made ofthe shaped memory
metal in order to effect a desired deflection. When introduced into the oral
cavity, catheter 14 can be advanced until a patient's gag response is initi~ted
Catheter 14 is then retracted back to prevent patient's g~gging The distal end of
electrode 12 can be semi-curved. The distal end can have a geometry to
conform to an exterior of the tongue.
In one embodiment of the invention catheter 14 is a handpiece. In this
embodiment, a separate handle 16 is not necess~ry Debulking appal~L~ls 10 is
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used to treat an interior region of the tongue. Catheter 14 has a distal end that is
sized to be positioned within an oral cavity. Ablation source delivery device 12is at least partially positioned within an interior of catheter 14. Ablation source
delivery device 12 includes ablation delivery surface 30. Ablation source
delivery device 20 is coupled to ablation source delivery device 12 and calibrated
to advance ablation source delivery device 12 from catheter 14, including but not
limited to a distal position of catheter 14, into the interior of the tongue when
catheter 14 is positioned adj~c~nt to a surface of the tongue. Ablation source
delivery device 12 is advanced an advancement distance 33 from catheter 14 of
sufficient length to treat the interior region of the tongue with ablation energy
and/or an ablation effect without d~m~ging the hypoglossal nerve or the surface
of the tongue.
Catheter 14 can be malleable in order to conform to the surface of the
tongue when a selected ablation target site is selected. An encapsulated soft
metal, such as copper, or an annealed metal/plastic material can be used to formmalleable catheter 14. All or a portion of catheter 14 may be malleable or made
of a shaped memory metal.
For many applications it is desirable for a distal end 14' of catheter 14 to
be deflectable. This can be achieved mech~nically or with the use of memory
metals. A steering wire, or other mechanical structure, can be ~tt~çhed to either
the exterior or interior of distal end 14'. In one embodiment, a deflection knoblocated 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 mech~nical devices can be used in place of the
steering wire. The deflection may be desirable for tissue sites with difficult
access.
Controlled volumetric reduction of the tongue, under feedback control is
used to achieve an effective opening in the airway passage. A variety of dirreltll~
pain killing medicaments, including but not limited to Xylocaine, may be used. Adigital ultrasonic measurement system can be used. The ultrasound measurement
quantifies biological shape changes, provides ultrasonic ~ .c~ .ssion and
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reception, uses piezoelectric tr~nsducers (crystals) and provides time of flightdata.
A disinfectant medium introduction member 21 may also be introduced
into the oral cavity. The disinfectant medium can be introduced prior to
ablation, during ablation and/or after the ablation. It can be delivered
continuously. The level of disinfection of the oral cavity is selectable as the
volume of the oral cavity that is disinfected. The degree of disinfection varies.
Disinfection is provided to reduce infection of the ablated body structure.
Disinfectant medium introduction member 21 can be introduced before, after or
during the introduction of ablation appal aL~Is 10 into the oral cavity.
Additionally, disinfectant meflillm introduction member 21 can be removed at thesame time or at a dirrel elll time that ablation app~ ~IS 10 is removed from theoral cavity.
Disinfectant medium introduction member 21 can be included in ablation
apparatus 1 0, in an interior of catheter 14 or at an exterior of catheter 14, and
may be an introducer with a lumen configured to introduce a disinfectant agent
from a disinfectant agent source 23 into all or a selected portion of the oral
cavity. Disinfectant me~illm introduction member 21 can be capable of
movement within the oral cavity in order to provide for disinfection of all or only
a portion of the oral cavity. For purposes of this disclosure, the oral cavity is
that body internal environment where infectious germs may be introduced into
the ablated tongue, soft tissue structure, and the like. Disinfectant medium
introduction member 21 may be slideably positioned in catheter 14 or at its
exterior. Alternatively, disinfectant me~illm introduction member 21 can be an
optical fiber coupled to a light energy source, in~lutling but not limited to a W
source 25. The optical fiber can also be slideably be positioned in the oral
cavity. The optical fiber is configured to provide for the selective disinfection of
all or only a portion of the oral cavity and can have a variety of di~l elll distal
ends to achieve this purpose.
Suitable disinfectant agents include but are not limited to Peridex, an oral
rinse co"~ g 0.12% chlorhexidine glllrin~te (1, 1'-hexanethylenebis[5-(p-
12
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chlorophenyl) biganide} di-D-gluconate in a base co~ g water, 11.6%
alcohol, glycerin, PEG 40 sorbitan arisoterate, flavor, dosium saccharin, and
FD&C Blue No. 1.
It will be appreciated that a variety of di~elenl disinfectants can be
employed, including other electromagnetic wavelengths, and various chemical
compositions.
Electrodes 12 are at least partial}y positioned in an interior of catheter 14.
Each electrode 12 is advanced and retracted through a port 18 formed in an
exterior surface of catheter 14. Advancement and retraction device advances
electrodes 12 out of catheter 14, into an interior of a body structure and
retracted back into catheter 14. Electrodes 12 pierce an exterior surface of thetongue and are directed to an interior region of the tongue. Sufficient
electromagnetic energy is delivered by electrodes 12 to the interior ofthe tongue
to cause the tongue to become suff1ciently ablated and debulked. Electrodes 12
can be hollow to receive a variety of di~lenl infusion mediums, inclllrling but
not limited to saline. Electrodes 12 may be limited in the ~ t~nce that they canbe advanced into the tongue. This is achieved with an insulation sleeve, a
structure located on electrodes 12 which limits their advancement, or a structure
coupled to catheter which limits the advancement of electrodes 12, such as a
stop and the like.
The dish~e.;lanl mçclillm can be introduced prior to ablation, during
ablation and/or after the ablation. It can be delivered continuously. The level of
disinfection of the oral cavity is selectable as is the volume of the oral cavity that
is disinfected. The degree of disinfection varies. Disinfection is provided to
reduce infection of the ablated body structure.
An ablation delivery surface, such as an electrom~gnetic energy delivery
surface 30 of electrode 12 can be adjusted by inclusion of an adjllstable or non-
adjustable insulation sleeve 32 (Figures 3, 4, and 5). Insulation sleeve 32 can be
advanced and retracted along the exterior surface of electrode 12 in order to
increase or decrease the length ofthe electrom~gnetic energy delivery surface
30. Insulation sleeve 32 can be made of a variety of materials inchlding but not
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limited to nylon, polyimides, other thermop}astics and the like. The size of
electrom~gnetic energy delivery surface 30 can be varied by other methods
including but not limited to creating a segmented electrode with a plurality of
electrodes that are capable of being multiplexed and individually activated, andthe like.
Referring specifically to Figure 4, ablation source delivery device 12 has
an advancement length 33 that extends from an exterior surface of catheter 14
and is directed into the interior ofthe tongue. Advancement length 33 is
sufficient to position ablation delivery surface 30 at a selected tissue site in the
interior of the tongue. Ablation delivery surface 30 is of sufficient length so that
the ablation effect is delivered to the selected tissue site, create a desired level of
ablation at the selected tissue site without causing damage to the hypoglossal
nerve. Ablation delivery surface 30 is not always at the distal end of ablation
source delivery device 12. Insulation 32 can also be positioned at the distal end
of ablation source delivery device 12. In this embodiment, ablation delivery
surface 30 does not extend to the distal end of ablation source delivery device
12. However, ablation delivery surface 30 still delivers a sufficient ablation
effect to create a desired level of cell necrosis in the interior of the tongue at the
selected tissue site without ~m~ging the hypoglossal nerve and/or damage to
the surface of the tongue. Additionally, only one side or a portion of a side ofablation source delivery device 12 ~an be in~ ted This also provides for an
ablation source delivery device 12 which can be positioned throughout the
tongue, inclu(lin~ adjacent to a hypoglossal nerve. Where ablation source
delivery device 12 is aclj~c~nt to the hypoglossal nerve, ablation source delivery
device 12 isinc~ te~
In one embodiment, advancement length 33 is 1.2 to 1.5 cm, and the
length of ablation delivery surface 30 is 5 to lO mm, more preferably about 8
mm.
In another embodiment, advancement length 33 is insufficient to reach
the hypoglossal nerve when introduced through any of the tongue surfaces,
particularly the dorsum of the tongue.
14
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Advancement device 20 is configured to advance at least a portion of
each ablation source delivery device 12 to a placement position in the interior of
the tongue. Advancement device 20 can also be configured to retract each
ablation source delivery device 12. At the placement position, ablation deliveryS surface delivers sufficient ablation energy and/or effect to reduce a volume of the
selected site without d~m~ging a hypoglossal nerve and/or a surface of the
tongue. In one embodiment, ablation source delivery device advancement and
retraction device 20, with or without guide tracks 23, directs the delivery of
ablation source delivery device 12 from catheter 14 into the interior ofthe
tongue at an angle of 60 to 90 degrees relative to a longitutlin~l axis of catheter
14, and preferably about 70 degrees.
In certain embodiments, ablation source delivery device 12 has a
geometric shape, including but not limited to a curved configuration that includes
one or more in~ ted surfaces, either partially in~ ted on one side, at a
proximal end, at a distal end, and the like, that is configured to reduce the
volume of the selected tissue site without d~m~ging a hypoglossal nerve. In one
embodiment, ablation source delivery device 12 is introduced through any
tongue surface and is configured so that a section of ablation source delivery
device 12 which may be positioned close to the hypoglossal nerve is provided
with insulation 32. As previously noted, insulation 32 can be positioned at
di~elenl sites of ablation source delivery device 12.
Handle 16 can comprise a connector 34 coupled to retraction and
advancement device 20. Connector 34 provides a coupling of electrodes 12 to
power, feedback control, temperature and/or im~ing systems. An
RF/temperature control block 36 can be included.
In one embodiment, the physician moves retraction and advancement
device 20 in a direction toward a distal end of connector 34. Electrodes 12 can
be spring loaded. When retraction and advancement device 20 is moved back,
springs cause selected electrodes 12 to advance out of catheter 14.
One or more cables 38 couple electrodes 12 to an electromagnetic energy
source 40. A variety of energy sources 40 can be used with the present
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invention to transfer electromagnetic energy to the interior of a body structure,
including but not limited to RF, microwave, ultrasound, coherent light and
thermal transfer. Preferably, energy source 40 is a RF generator. When a RF
energy source is used, the physician can activate RF energy source 40 by the useof a foot switch (not shown) coupled to RF energy source 40.
One or more sensors 42 may be positioned on an interior or exterior
surface of electrode 12, insulation sleeve 32, or be independently inserted intothe interior of the body structure. Sensors 42 permit accurate measurement of
temperature at a tissue site in order to determine, (i) the extent of ablation, (ii)
the amount of ablation, (iii) whether or not further ablation is needed, and (iv)
the boundary or periphery of the ablated geometry. Further, sensors 42 prevent
non-targeted tissue from being destroyed or ablated.
Sensors 42 are of conventional design, including but not limited to
thermistors, therrnocouples, resistive wires, and the like. Suitable sensors 42
include a T type thermocouple with copper constantene, J type, E type, K type,
fiber optics, resistive wires, thermocouple IR detectors, and the like. It will be
appreciated that sensors 42 need not be thermal sensors.
Sensors 42 measure temperature and/or impedance to permit ablation
monitoring. This reduces damage to tissue surrounding the targeted ablation
mass. By monitoring the temperature at various points within the interior of thebody structure the periphery of ablation can be ascertained and it is possible to
determine when the ablation is completed. If at any time sensor 42 determines
that a desired ablation tempel a~ure is exceeded, then an appropriate feedback
signal is received at energy source 40 and the amount of energy delivered is
re~ ted
Ablation or debulking apparatus 10 can include vi~u~li7~tion capability
including but not lirnited to a viewing scope, an expanded eyepiece, fiber optics,
video im~ging, and the like.
Additionally, ultrasound im~ging can be used to position the electrodes
12 and/or determine the amount of ablation. One or more ultrasound
transducers 44 can be positioned in or on electrode 12, catheter 14, or on a
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separate device. An im~ing probe may also be used internally or externally to
the selected tissue site. A suitable im~ging probe is Model 21362, m~ntlf~ctllred
and sold by Hewlett Packard Company. Each ultrasound tr~n~dllcer 44 is
coupled to an ultrasound source (not shown).
With reference now to Figure 6 catheter 14 is shown as being introduced
into the oral cavity and multiple RF electrodes 12 are advanced into the interior
of the tongue creating di~el e"l ablation zones 46. Using RF, ablation ap,~a, al~ls
10 can be operated in either bipolar or monopolar modes. In Figure 6,
electrodes 12 are operated in the bipolar mode, creating sufficient ablation zones
46 to debulk the tongue without affecting the hypoglossal nerves and creating a
larger airway passage. With this debulking, the back of the tongue moves in a
forward direction away from the air passageway. The result is an increase in thecross-sectional diameter of the air passageway.
Using RF, ablation apparatus 10 can also be operated in the monopolar
mode. A groundpad can be positioned in a convenient place such as under the
chin. A single electrode 12 is positioned in the tongue to create a first ablation
zone 46. Electrode 12 can then be retracted from the interior of the tongue,
catheter 14 moved, and electrode 12 is then advanced from catheter 14 into
another interior section of the tongue. A second ablation zone 46 is created.
This procedure can be completed any number of times to form di~lel-l ablation
regions in the interior ofthe tongue. More than one electrode 12 can be
introduced into the tongue and operated in the bipolar mode. ~lectrodes 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 46.
Referring now to Figures 7 through 15, various anatomical views of the
tongue and other structures are illustrated. The di~lenl anatomical structures
are as follows: the genioglossus muscle, or body of the tongue is denoted as 48;the geniohyoid muscle is 50; the mylohyoid muscle is 52; the hyoid bone is 54;
the tip of the tongue is 56; the ventral surface of the tongue is denoted as 58; the
dorsum of the tongue is denoted as 60; the inferior dorsal of the tongue is
denoted as 62; the reflex of the vallecula is 64; the lingual follicles are denoted as
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66; the uvula is 68; the adenoid area is 70; the lateral border of the tongue is 72;
the circumvallate papilla is 74, the palatine tonsil is 76; the pharynx is 78; the
reduntl~nt pharyngeal tissue is 80; the foramen cecum is 82; the hypoglossal
nerve is 84, and the lingual frenum of the tongue is 86.
Dorsum 60 is divided into an anterior 2/3 and inferior dorsal 62. The
delineation is determined by circumvallate papilla 74 and foramen cecum 82.
Inferior dorsal 62 is the dorsal surface inferior to circumvallate papilla 74 and
superior reflex of the vallecula 64. Reflex of the vallecula 64 is the deepest
portion of the surface of the tongue contiguous with the epiglottis. Lingual
follicles 66 comprise the lingual tonsil.
Catheter 14 can be introduced through the nose or through the oral
cavity. l~lectrodes 12 can be inserted into an interior of the tongue through
dorsum surface 60, inferior dorsal surface 62, ventral surface 58, tip 56 or
geniohyoid muscle 50. Additionally, electrodes may be introduced into an
interior of lingual follicles 66 and into adenoid area 70. Once electrodes 12 are
positioned, insulation sleeve 32 may be adjusted to provided a desired
electromagnetic energy delivery surface 30 for each electrode 12.
Ablation zones 46 are created without d~m~ing hypoglossal nerves 84.
This creates a larger air way passage and provides a treatment for sleep apnea.
In all instances, the positioning of electrodes 12, as well as the creation of
ablation zones 46 is such that hypoglossal nerves 84 are not ablated or damaged.The ability to swallow and speak is not impaired.
In one embodiment, RF electrode 12 are placed on the dorsum surface
of the tongue. The first electrode is positioned 0. 5 cm proximal to the
circumvallate pappilla. The other electrodes are spaced 1.6 cm apart and are 1
cm offa central axis ofthe tongue. In one embodiment, 465 MHz RF was
applied. The telllpel~lure at the distal end of electrode 12 was about 100
degrees C. The temperature at the distal end of the insulation sleeve 32 was
about 60 degrees C. In another embodiment, the telllpel a~.~re at the distal end of
insulation sleeve 32 was 43 degrees C and above. RF energy can be applied as
short duration pulses with low frequency RF. Precise targeting of a desired
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WO 97/41785 PCT/US96/13426
ablation site is achieved. One or more electrodes 12 may be used to create
volumetric three-dimensional ablation. A variety of ablation geometries are
possible, including but not limited to rectiline~r, polyhedral, redetermined shapes,
symmetrical and non-symmetrical.
Referring now to Figures 16 and 17 an open or closed loop feedback
system couples sensors 42 to energy source 40. The temperature of the tissue,
or of electrode 12 is monitored, and the output power of energy source 40
adjusted accordingly. Additionally, the level of disinfection in the oral cavity can
be monitored. 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 a microprocessor 88 to serve as a controller,
watch the temperature, adjust the RF power, look at the result, refeed the result,
and then modulate the power.
With the use of sensors 42 and the feedback control system a tissue
adj~cent to RF electrodes 12 can be lllA;I~lAi~ed at a desired temperature for aselected period of time without impeding out. Each RF electrode 12 is
connected to resources which generate an independent output for each RF
electrode 12. An output m~intAins a selected energy at RF electrodes 12 for a
selected length of time.
When an RF electrode is used, current delivered through RF electrodes
12 is measured by current sensor 90. Voltage is measured by voltage sensor 92.
Impedance and power are then calculated at power and impedance calculation
device 94. These values can then be displayed at user interface and display 96.
Signals representative of power and impedance values are received by a
controller 98.
A control signal is generated by controller 98 that is proportional to the
di~erence between an actual measured value, and a desired value. The control
signal is used by power circuits 100 to adjust the power output in an appl op.iate
amount in order to IIIAil~lAi" the desired power delivered at respective RF
electrodes 12.
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In a similar manner, temperatures detected at sensors 42 provide
feedback for ~ a selected power. The actual temperatures are
measured at temperature measurement device 102, and the temperatures are
displayed at user interface and display 96. A control signal is generated by
S controller 98 that is proportional to the difference between an actual measured
temperature, and a desired temperature. The control signal is used by power
circuits 100 to adjust the power output in an appropliate amount in order to
m~int~in the desired temperature delivered at the respective sensor. A
multiplexer can be included to measure current, voltage and temperature, at the
numerous sensors 42, and energy can be delivered to RF electrodes 12 in
monopolar or bipolar fashion.
Controller 98 can be a digital or analog controller, or a computer with
software. When controller 98 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 is a program memory and a data memory.
User interface and display 96 includes operator controls and a display.
Controller 98 can be coupled to im~gin~ systems, incl~ldin~ but not lin ited to
ultrasound, CT scanners, X-ray, MRI, mammographic X-ray and the like.
Further, direct visualization and tactile im~ging can be utilized.
The output of current sensor 90 and voltage sensor 92 is used by
controller 98 to m~int~in 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 98, and a preset amount of
energy to be delivered can also be profiled. Other sensors similar to sensors 90and 92 can be used by controller 98 for other ablation source delivery devices 12
to ~ a controllable amount of an ablation energy and/or ablative agent.
Circuitry, software and feedback to controller 98 result in process
control, and the m~int~n~nce of the selected power that is independent of
changes in voltage or current, and are used to change, (i) the selected power,
(ii) the duty cycle (on-off and wattage), (iii) bipolar or monopolar energy
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delivery, and (iv) infusion medium delivery, including flow rate and pressure.
These process variables are controlled and varied, while m~ the desired
delivery of power independent of changes in voltage or current, based on
temperatures monitored at sensors 42.
Current sensor 90 and voltage sensor 92 are connected to the input of an
analog amplifier 104. Analog amplifier 104 can be a conventional di~lenlial
amplifier circuit for use with sensors 42. The output of analog amplifier 104 issequentially connected by an analog multiplexer 106 to the input of A/D
converter 108. The output of analog amplifier 104 is a voltage which represents
the respective sensed temperatures. Digitized amplifier output voltages are
supplied by A/D converter 108 to microprocessor 88. Microprocessor 88 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 88 sequentially receives and stores digital representations
of impedance and temperature. Each digital value received by microprocessor
88 corresponds to di~elen~ temperatures and impedances.
Calculated power and impedance values can be indicated on user
interface and display 96. Alternatively, or in addition to the numerical indication
of power or impedance, calculated impedance and power values can be
compared by microprocessor 88 with power and impedance limits. When the
values exceed predetermined power or impedance values, a warning can be given
on user interface and display 96, and additionally, the delivery of RF energy can
be reduced, modified or interrupted. A control signal from microprocessor 88
can modify the power level supplied by energy source 40.
Figure 18 illustrates a block diagram of a temperature/impedance
feedback system that can be used to control cooling medium flow rate through
catheter 14. Electromagnetic energy is delivered to electrode 12 by energy
source 44, and applied to tissue. A monitor 110 ascertains tissue impedance,
based on the energy delivered to tissue, and compares the measured impedance
value to a set value. If the measured impedance exceeds the set value a disabling
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W O 97/41785 PCTrUS96/13426
signal 112 is ll ~n~ led to energy source 40, ceasing further delivery of energyto electrode 12. If measured impedance is within acceptable limits, energy
continues to be applied to the tissue. During the application of energy to tissue
sensor 42 measures the temperature oftissue and/or electrode 12. A comparator
114 receives a signal representative ofthe measured temperature and compares
this value to a pre-set signal representative of the desired temperature.
Comparator 114 sends a signal to a flow regulator 116 representing a need for a
higher cooling medium flow rate, if the tissue temperature is too high, or to
m~int~in the flow rate if the temperature has not exceeded the desired
temperature.
EXAMPLE 1
Ablation apparatus 10 was used to deterrnine two-dimensional shrinkage
of a bovine. RF volumetric reduction was achieved using a single needle
electrode. Four mini~t~re ultrasonic crystals were positioned to form a square.
Measurements were taken at control and post volumetric reduction at 15 watts
initially with a 13% volumetric reduction, and 15 watts for 4 hours with an
additional 4% volumetric reduction. A total 17% volumetric reduction was
achieved.
EXAMPLE 2
Ablation appa ~LIlslO was used to determine three-dimensional
shrinkage of a bovine tongue. RF volumetric reduction was achieved with a
single needle electrode with eight mini~tl-re ultrasonic crystals, creating a cube.
Application of 16 watts initially produced a 17% volumetric reduction of the
tongue, 25 watts applied initially produced a 25% volumetric redllcti()n, and 25watts after hours produced an additional 4% reduction, for a total volumetric
reduction of 29%.
EXAMPLE 3
A 35% volumetric reduction was achieved in porcine in vivo, with three
dimensional gross at 20 watts initial application.
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Referring now to Figure 19, ablation volume dimensions were measured
with a multidimensional digital sonomicrometry. An average decrease in the Z
direction was 20%, and volume shrinkage was 26%. Three-dimensional
shrinkage of tongue tissue due to in vivo RF ablation with the needle, ablation
with 20 Watts) is presented in Figure 20. Control volume before ablation is
compared with a post-ablation volume.
Figure 20 illustrates two-dimensional shrinkage of a bovine tongue tissue
due to RF ablation with a needle electrode. The before and after ablation results
are illustrated.
Figure 21 illustrates in graph form ablation at 16 Watts resulted in a 17%
volume shrinkage of the tissue in post-ablation verses control. Ablation at 25
watts resulted in a 25% volume shrinkage after ablation. An additional 4% area
shrinkage was obtained after in long-term post ablation (4 hours) verses post-
ablation.
Figure 22 illustrates a percent volume change after RF ablation. 16
Watts, ablation at 16 Watts for 20 min~ltes; 25 Watts, ablation at 25 Watts for 20
min~tes; 25 Watts (4 hours), and long tern post ablation (4 hours after 25 Wattsablation).
The foregoing description of a plerelled 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 apparen~ to practitioners skilled in this
art. It is inten(led that the scope of the invention be defined by the followingclaims and their equivalents.
What is claimed is:
. ~
