U.S. patent number RE43,009 [Application Number 12/572,005] was granted by the patent office on 2011-12-06 for apparatus and method for reducing subcutaneous fat deposits by electroporation.
This patent grant is currently assigned to AngioDynamics, Inc.. Invention is credited to Victor I. Chornenky, Ali Jaafar.
United States Patent |
RE43,009 |
Chornenky , et al. |
December 6, 2011 |
Apparatus and method for reducing subcutaneous fat deposits by
electroporation
Abstract
An apparatus and method for minimally invasive treatment of deep
subcutaneous fat deposits in lieu of cosmetic surgery is disclosed.
The apparatus comprises a high voltage pulse generator connected to
two or more needle electrodes at least one of which is configured
for placement deeply under the skin in a treatment site of the
patient's body. High voltage pulses, delivered to the electrodes,
create an electric field that kills subcutaneous fat cells.
Inventors: |
Chornenky; Victor I.
(Minnetonka, MN), Jaafar; Ali (Eden Prairie, MN) |
Assignee: |
AngioDynamics, Inc. (Latham,
NY)
|
Family
ID: |
27669329 |
Appl.
No.: |
12/572,005 |
Filed: |
October 1, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
09931672 |
Aug 17, 2001 |
6892099 |
|
|
|
60358443 |
Feb 22, 2002 |
|
|
|
|
60267106 |
Feb 8, 2001 |
|
|
|
|
60225775 |
Aug 17, 2000 |
|
|
|
Reissue of: |
10369020 |
Feb 19, 2003 |
6795728 |
Sep 21, 2004 |
|
|
Current U.S.
Class: |
607/2;
607/72 |
Current CPC
Class: |
A61N
1/0502 (20130101); A61N 1/328 (20130101); A61N
1/327 (20130101); A61B 2018/00613 (20130101) |
Current International
Class: |
A61N
1/18 (20060101) |
Field of
Search: |
;607/2,3,72,115,116,148,152,153 ;600/373-375,377,378,381 ;604/20
;128/907 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
863111 |
|
Jan 1953 |
|
DE |
|
4000893 |
|
Jul 1991 |
|
DE |
|
0378132 |
|
Jul 1990 |
|
EP |
|
0935482 |
|
May 2005 |
|
EP |
|
9639531 |
|
Dec 1996 |
|
WO |
|
0020554 |
|
Apr 2000 |
|
WO |
|
0107583 |
|
Feb 2001 |
|
WO |
|
0107584 |
|
Feb 2001 |
|
WO |
|
0107585 |
|
Feb 2001 |
|
WO |
|
0181533 |
|
Nov 2001 |
|
WO |
|
04037341 |
|
May 2004 |
|
WO |
|
Other References
Amasha, et al., Quantitative Assessment of Impedance Tomography for
Temperature Measurements in Microwave Hyperthermia, Clin. Phys.
Physiol. Meas., 1998, Suppl. A, 49-53. cited by other .
Andreason, Electroporation as a Technique for the Transfer of
Macromolecules into Mammalian Cell Lines, J. Tiss. Cult. Meth.,
15:56-62, 1993. cited by other .
Baker, et al., Calcium-Dependent Exocytosis in Bovine Adrenal
Medullary Cells with Leaky Plasma Membranes, Nature, vol. 276, pp.
620-622, 1978. cited by other .
Barber, Electrical Impedance Tomography Applied Potential
Tomography, Advances in Biomedical Engineering, Beneken and
Thevenin, eds., IOS Press, 1993. cited by other .
Beebe, S.J., et al., Nanosecond pulsed electric field (nsPEF)
effects on cells and tissues: apoptosis induction and tumor growth
inhibition. PPPS-2001 Pulsed Power Plasma Science 2001, 28.sup.th
IEEE International Conference on Plasma Science and 13.sup.th IEEE
International Pulsed Power Conference, Digest of Technical Papers
(Cat. No. 01CH37251). IEEE, Part vol. 1, 2001, pp. 211-215, vol. I,
Piscataway, NJ, USA. cited by other .
Blad, et al., Impedance Spectra of Tumour Tissue in Comparison with
Normal Tissue; a Possible Clinical Application for Electrical
Impedance Tomography, Physiol. Meas. 17 (1996) A105-A115. cited by
other .
Bown, S.G., Phototherapy of tumors. World J. Surgery, 1983. 7: p.
700-9. cited by other .
BPH Management Strategies: Improving Patient Satisfaction, Urology
Times, May 2001, vol. 29, Supplement 1. cited by other .
Brown, et al., Blood Flow Imaging Using Electrical Impedance
Tomography, Clin. Phys. Physiol. Meas., 1992, vol. 13, Suppl. A,
175-179. cited by other .
Chandrasekar, et al., Transurethral Needle Ablation of the Prostate
(TUNA)--a Propsective Study, Six Year Follow Up, (Abstract),
Presented at 2001 National Meeting, Anaheim, CA, Jun. 5, 2001.
cited by other .
Coates, C.W.,et al., "The Electrical Discharge of the Electric Eel,
Electrophorous Electricus," Zoologica, 1937, 22(1), pp. 1-32. cited
by other .
Cook, et al., ACT3: A High-Speed, High-Precision Electrical
Impedance Tomograph, IEEE Transactions on Biomedical Engineering,
vol. 41, No. 8, Aug. 1994. cited by other .
Cowley, Good News for Boomers, Newsweek, Dec. 30, 1996/Jan. 6,
1997. cited by other .
Cox, et al., Surgical Treatment of Atrial Fibrillation: A Review,
Europace (2004) 5, S20-S-29. cited by other .
Crowley, Electrical Breakdown of Biomolecular Lipid Membranes as an
Electromechanical Instability, Biophysical Journal, vol. 13, pp.
711-724, 1973. cited by other .
Davalos, et al., Tissue Ablation with Irreversible Electroporation,
Annals of Biomedical Engineering, vol. 33, No. 2, Feb. 2005. cited
by other .
Davalos, et al ., Theoretical Analysis of the Thermal Effects
During In Vivo Tissue Electroporation, Bioelectrochemistry, vol.
61, pp. 99-107, 2003. cited by other .
Davalos, et al., A Feasibility Study for Electrical Impedance
Tomography as a Means to Monitor T issue Electroporation for
Molecular Medicine, IEEE Transactions on Biomedical Engineering,
vol. 49, No. 4, Apr. 2002. cited by other .
Davalos, Real-Time Imaging for Molecular Medicine through
Electrical Impedance Tomography of Electroporation, Dissertation
for Ph.D. in Engineering-Mechanical Engineering, Graduate Division
of University of California, Berkeley, 2002. cited by other .
Dean, Nonviral Gene Transfer to Skeletal, Smooth, and Cardiac
Muscle in Living Animals, Am J. Physiol Cell Physiol 289: 233-245,
2005. cited by other .
Dev, et al., Sustained Local Delivery of Heparin to the Rabbit
Arterial Wall with an Electroporation Catheter, Catheterization and
Cardiovascular Diagnosis, Nov. 1998, vol. 45, No. 3, pp. 337-343.
cited by other .
Dev, et al., Medical Applications of Electroporation, IEEE
Transactions of Plasma Science, vol. 28, No. 1, pp. 206-223, Feb.
2000. cited by other .
Duraiswami, et al., Boundary Element Techniques for Efficient 2-D
and 3-D Electrical Impedance Tomography, Chemical Engineering
Science, vol. 52, No. 13, pp. 2185-2196, 1997. cited by other .
Duraiswami, et al., Efficient 2D and 3D Electrical Impedance
Tomography Using Dual Reciprocity Boundary Element Techniques,
Engineering Analysis with Boundary Elements 22, (1998) 13-31. cited
by other .
Duraiswami, et al., Solution of Electrical Impedance Tomography
Equations Using Boundary Element Methods, Boundary Element
Technology XII, 1997, pp. 226-237. cited by other .
Edd, J., et al., In-Vivo Results of a New Focal Tissue Ablation
Technique: Irreversible Electroporaton, IEEE Trans. Biomed. Eng. 53
(2006) p. 1409-1415. cited by other .
Erez, et al., Controlled Destruction and Temperature Distributions
in Biological Tissues Subjected to Monoactive Electrocoagulation,
Transactions of the ASME: Journal of Mechanical Design, vol. 102,
Feb. 1980. cited by other .
Foster, R.S., et al., High-intensity focused ultrasound in the
treatment of prostatic disease. Eur. Urol., 1993. 23: 44-7). cited
by other .
Fox, et al., Sampling Conductivity Images via MCMC, Mathematics
Department, Auckland University, New Zealand, May 1997. cited by
other .
Gauger, et al., A Study of Dielectric Membrane Breakdown in the
Fucus Egg, J. Membrane Biol., vol. 48, No. 3, pp. 249-264, 1979.
cited by other .
Gehl, et al., In Vivo Electroporation of Skeletal Muscle:
Threshold, Efficacy and Relation to Electric Field Distribution,
Biochimica et Biphysica Acta 1428, 1999, pp. 233-240. cited by
other .
Gencer, et al., Electrical Impedance Tomography: Induced-Current
Imaging Achieved with a Multiple Coil System, IEEE Transactions on
Biomedical Engineering, vol. 43, No. 2, Feb. 1996. cited by other
.
Gilbert, et al., Novel Electrode Designs for Electrochemotherapy,
Biochimica et Biophysica Acta 1334, 1997, pp. 9-14. cited by other
.
Gilbert, et al., The Use of Ultrasound Imaging for Monitoring
Cryosurgery, Proceedings 6.sup.th Annual Conference, IEEE
Engineering in Medicine and Biology, 107-111, 1984. cited by other
.
Glidewell, et al., The Use of Magnetic Resonance Imaging Data and
the Inclusion of Anisotropic Regions in Electrical Impedance
Tomography, Biomed, Sci. Instrum. 1993; 29: 251-7. cited by other
.
Gothelf, et al., Electrochemotherapy: Results of Cancer Treatment
Using Enhanced Delivery of Bleomycin by Electroporation, Cancer
Treatment Reviews 2003: 29: 371-387. cited by other .
Griffiths, et al., A Dual-Frequency Electrical Impedance Tomography
System, Phys. Med. Biol., 1989, vol. 34, No. 10, pp. 1465-1476.
cited by other .
Griffiths, The Importance of Phase Measurement in Electrical
Impedance Tomography, Phys. Med. Biol., 1987, vol. 32, No. 11, pp.
1435-1444. cited by other .
Griffiths, Tissue Spectroscopy with Electrical Impedance
Tomography: Computer Simulations, IEEE Transactions on Biomedical
Engineering, vol. 42, No. 9, Sep. 1995. cited by other .
Gumerov, et al., The Dipole Approximation Method and Its Coupling
with the Regular Boundary Element Method for Efficient Electrical
Impedance Tomography, Boundary Element Technology XIII, 1999. cited
by other .
Hapala, Breaking the Barrier: Methods for Reversible
Permeabilization of Cellular Membranes, Critical Reviews in
Biotechnology, 17(2): 105-122, 1997. cited by other .
Heller, et al., Clinical Applications of Electrochemotherapy,
Advanced Drug Delivery Reviews, vol. 35, pp. 119-129, 1999. cited
by other .
Ho, et al., Electroporation of Cell Membranes: A Review, Critical
Reviews in Biotechnology, 16(4): 349-362, 1996. cited by other
.
Holder, et al., Assessment and Calibration of a Low-Frequency
System for Electrical Impedance Tomography (EIT), Optimized for Use
in Imaging Brain Function in Ambulant Human Subjects, Annals of the
New York Academy of Science, vol. 873, Issue 1, Electrical BI, pp.
512-519, 1999. cited by other .
Huang, et al., Micro-Electroporation: Improving the Efficiency and
Understanding of Electrical Permeabilization of Cells, Biomedical
Microdevices, vol. 2, pp. 145-150, 1999. cited by other .
Hughes, et al., An Analysis of Studies Comparing Electrical
Impedance Tomography with X-Ray Videofluoroscopy in the Assessment
of Swallowing, Physiol. Meas. 15, 1994, pp. A199-A209. cited by
other .
Issa, et al., The TUNA Procedure for BPH: Review of the Technology:
The TUNA Procedure for BPH: Basic Procedure and Clinical Results,
Reprinted from Infections in Urology, Jul./Aug. 1998 and Sep./Oct.
1998. cited by other .
Ivanu{hacek over (s)}a, et al., MRI Macromolecular Contrast Agents
as Indicators of Changed Tumor Blood Flow, Radiol. Oncol. 2001;
35(2): 139-47. cited by other .
Jaroszeski, et al., In Vivo Gene Delivery by Electroporation,
Advanced Drug Delivery Review, vol. 35, pp. 131-137, 1999. cited by
other .
Kinosita, et al., Hemolysis of Human Erythrocytes by a Transient
Electric Field, Proc. Natl. Acad. Sci. USA, vol. 74, No. 5, pp.
1923-1927, 1977. cited by other .
Liu, et al., Measurement of Pharyngeal Transit Time by Electrical
Impedance Tomography, Clin. Phys. Physiol. Meas., 1992, vol. 13,
Suppl. A, pp. 197-200. cited by other .
Lundqvist, et al., Altering the Biochemical State of Individual
Cultured Cells and Organelles with Ultramicroelectrodes, Proc.
Natl. Acad. Sci. USA, vol. 95, pp. 10356-10360, Sep. 1998. cited by
other .
Lurquin, Gene Transfer by Electroporation, Molecular Biotechnology,
vol. 7, 1997. cited by other .
Lynn, et al., A New Method for the Generation and Use of Focused
Ultrasound in Experimental Biology, The Journal of General
Physiology, vol. 26, 179-193, 1942. cited by other .
Miklav{hacek over (c)}i{hacek over (c)}, et al., A Validated Model
of an in Vivo Electric Field Distribution in Tissues for
Electrochemotherapy and for DNA Electrotransfer for Gene Therapy,
Biochimica et Biophysica Acta 1523 (2000), pp. 73-83. cited by
other .
Miklav{hacek over (c)}i{hacek over (c)}, et al., The Importance of
Electric Field Distribution for Effective in Vivo Electroporation
of Tissues, Biophysical Journal, vol. 74, May 1998, pp. 2152-2158.
cited by other .
Miller, L., et al., Cancer cells ablation with irreversible
electroporation, Technology in Cancer Research and Treatment 4
(2005) 699-706. cited by other .
Mir, Therapeutic Perspectives of In Vivo Cell
Electropermeabilization, Bioelectrochemistry, vol. 53, pp. 1-10,
2000. cited by other .
Mir, L.M., et al., Electric Pulse-Mediated Gene Delivery to Various
Animal Tissues, in Advances in Genetics, Academic Press, 2005, p.
83-114. cited by other .
Mir, L.M. And Orlowski, S., The basis of electrochemotherapy, in
Electrochemotherapy, electrogenetherapy, and transdermal drug
delivery: electrically mediated delivery of molecules to cells,
M.J. Jaroszeski, R. Heller, R. Gilbert, Editors, 2000, Humana
Press, p. 99-118. cited by other .
Mir, et al., Effective Treatment of Cutaneous and Subcutaneous
Malignant Tumours by Electrochemotherapy, British Journal of
Cancer, vol. 77, No. 12, pp. 2336-2342, 1998. cited by other .
Mir, et al., Electrochemotherapy Potentiation of Antitumour Effect
of Bleomycin by Local Electric Pulses, European Journal of Cancer,
vol. 27, No. 1, pp. 68-72, 1991. cited by other .
Mir, et al., Electrochemotherapy, a Novel Antitumor Treatment:
First Clinical Trial, C.R. Acad. Sci. Paris, Ser. III, vol. 313,
pp. 613-618, 1991. cited by other .
Narayan, et al., Establishment and Characterization of a Human
Primary Prostatic Adenocarcinoma Cell Line (ND-1), The Journal of
Urology, vol. 148, 1600-1604, Nov. 1992. cited by other .
Naslund, Michael J., Transurethral Needle Ablation of the Prostate,
Urology, vol. 50, No. 2, Aug. 1997. cited by other .
Naslund, Cost-Effectiveness of Minimally Invasive Treatments and
Transurethral Resection (TURP) in Benign Prostatic Hyperplasia
(BPH), (Abstract), Presented at 2001 AUA National Meeting,,
Anaheim, CA, Jun. 5, 2001. cited by other .
Neumann, et al., Gene Transfer into Mouse Lyoma Cells by
Electroporation in High Electric Fields, J. Embo., vol. 1, No. 7,
pp. 841-845, 1982. cited by other .
Neumann, et al., Permeability Changes Induced by Electric Impulses
in Vesicular Membranes, J. Membrane Biol., vol. 10, pp. 279-290,
1972. cited by other .
Okino, et al., Effects of High-Voltage Electrical Impulse and an
Anticancer Drug on In Vivo Growing Tumors, Japanese Journal of
Cancer Research, vol. 78, pp. 1319-1321, 1987. cited by other .
Onik, et al., Sonographic Monitoring of Hepatic Cryosurgery in an
Experimental Animal Model, AJR American J. of Roentgenology, vol.
144, pp. 1043-1047, May 1985. cited by other .
Onik, et al., Ultrasonic Characteristics of Frozen Liver,
Cryobiology, vol. 21, pp. 321-328, 1984. cited by other .
Organ, L.W., Electrophysiological principles of radiofrequency
lesion making, Apply. Neurophysiol., 1976. 39: p. 69-76. cited by
other .
Pinero, et al., Apoptotic and Necrotic Cell Death Are Both Induced
by Electroporation in HL60 Human Promyeloid Leukaemia Cells,
Apoptosis, vol, 2, No. 3, 330-336, Aug. 1997. cited by other .
Precision Office TUNA System, When Patient Satisfaction is Your
Goal. cited by other .
Rols, M.P., et al., Highly Efficient Transfection of Mammalian
Cells by Electric Field Pulses: Application to Large Volumes of
Cell Culture by Using a Flow System, Eur. J. Biochem. 1992, 206,
pp. 115-121. cited by other .
Rubinsky, B., ed, Cryosurgery. Annu Rev. Biomed. Eng. vol. 2 2000.
157-187. cited by other .
Schmukler, Impedance Spectroscopy of Biological Cells, downloaded
from IEEE Xplore website. cited by other .
Sersa, et al., Reduced Blood Flow and Oxygenation in SA-1 Tumours
after Electrochemotherapy with Cisplatin, British Journal of
Cancer, 87, 1047-1054, 2002. cited by other .
Sersa, et al., Tumour Blood Flow Modifying Effects of
Electrochemotherapy: a Potential Vascular Targeted Mechanism,
Radiol. Oncol., 37(1): 43-8, 2003. cited by other .
Sharma, et al., Poloxamer 188 Decreases Susceptibility of
Artificial Lipid Membranes to Electroporation, Biophysical Journal,
vol. 71, No. 6, pp. 3229-3241, Dec. 1996. cited by other .
Shiina, S., et al, Percutaneous ethanol injection therapy for
hepatocellular carcinoma: results in 146 patients. AJR, 1993, 160:
p. 1023-8. cited by other .
Thompson, et al., To determine whether the temperature of 2%
lignocaine gel affects the initial discomfort which may be
associated with its instillation into the male urethra, BJU
International (1999), 84, 1035-1037. cited by other .
TUNA--Suggested Local Anesthesia Guidelines. cited by other .
Vidamed, Inc., Transurethral Needle Ablation (TUNA): Highlights
from Worldwide Clinical Studies, Vidamed's Office TUNA System.
cited by other .
Weaver, Electroporation: A General Phenomenon for Manipulating
Cells and Tissues, Journal of Cellular Biochemistry, 51: 426-435,
1993. cited by other .
Weaver, et al., Theory of Electroporation: A Review,
Bioelectrochemistry and Bioenergetics, vol. 41, pp. 136-160, 1996.
cited by other .
Zimmermann, et al., Dielectric Breakdown of Cell Membranes,
Biophysical Journal, vol. 14, No. 11, pp. 881-899, 1974. cited by
other .
Zlotta, et al., Possible Mechanisms of Action of Transurethral
Needle Ablation of the Prostate on Benign Prostatic Hyperplasia
Symptoms: a Neurohistochemical Study, Reprinted from Journal of
Urology, vol. 157, No. 3, Mar. 1997, pp. 894-899. cited by other
.
Zlotta, et al., Long-Term Evaluation of Transurethral Needle
Ablation of the Prostate (TUNA) for Treatment of Benign Prostatic
Hyperplasia (BPH): Clinical Outcome After 5 Years. (Abstract)
Presented at 2001 AUA National Meeting, Anaheim, CA--Jun. 5, 2001.
cited by other.
|
Primary Examiner: Getzow; Scott
Attorney, Agent or Firm: Ahn; Harry K. Abelman Frayne &
Schwab
Parent Case Text
.Iadd.CROSS-REFERENCE TO RELATED APPLICATIONS.Iaddend.
The present application claims priority from and is a
continuation-in-part of U.S. patent application Ser. No.
09/931,672, filed Aug. 17, 2001, entitled Apparatus and Method for
Reducing Subcutaneous Fat Deposits, Virtual Face Lift and Body
Sculpturing by Electroporation, .Iadd.now U.S. Pat. No. 6,892,099,
.Iaddend.the specification and drawings of which are incorporated
herein in their entirety by reference.Iadd., which claims the
benefit of U.S. Provisinal Application Ser. No. 60/267,106 filed
Feb. 8, 2001 and U.S. Provisional Application Ser. No. 60/225,775,
filed Aug. 17, 2000.Iaddend.. The present application also claims
priority from U.S. Provisional Patent Application Serial No.
60/358,443, filed Feb. 22, 2002, and entitled Apparatus and Method
for Reducing Subcutaneous Fat Deposits by Electroporation, the
specification and drawings of which are incorporated herein in
their entirety by reference.
Claims
What is claimed is:
1. An apparatus for reducing subcutaneous fat deposits by
electroporation comprising: an applicator comprising a plurality of
needle electrodes adapted for penetrating the skin of a patient and
applying a high amplitude pulsed electric field to the area of the
subcutaneous volume of fat tissue to be treated by electroporation,
at least one of said plurality of needle electrodes includes
insulated portions and a pair of uninsulated needle portions
axially separated along said needle electrode, wherein said
uninsulated needle portions form axially separate electrodes of
opposite polarity; and said insulated portions include proximal,
distal, and central insulated portions, said proximal insulated
portion being provided for insulating the skin of the patient
during an electroporation treatment, said distal insulated portion
being provided to avoid spark discharges to an adjacent needle
electrode and said central insulated portion separating said
electrodes, wherein said electrodes are disposed on said needle
electrode such that they are disposed within the subcutaneous fat
deposit during treatment; a generator of high voltage pulses for
applying pulsed electric field to the electrodes, said pulses
generating an electric field above the upper electroporation limit
for subcutaneous fat cells in the volume of subcutaneous fat tissue
to be treated; and connectors connecting said generator of high
voltage electrical pulses with corresponding needle electrodes
placed under the skin.
2. An apparatus according to claim 1 wherein said high voltage
pulses have a duration in a range of about 10 microseconds to about
10 millisecond.
3. An apparatus according to claim 1 wherein the amplitude of the
electric field applied to the treated volume falls in a range of
about 20 Volt/mm to about 2000 Volt/mm.
4. An apparatus according to claim 1 wherein high voltage pulses
are electrically balanced in such a manner that in average no
direct current is passing through the treatment volume.
5. An apparatus according to claim 1 wherein high voltage pulses
are rectangularly balanced.
6. A method for reducing deep subcutaneous fat deposits by
electroporation comprising: providing an applicator comprising a
set of high voltage needle electrodes adapted for penetrating the
skin of a patient and applying a high amplitude pulsed electric
field to the area of the subcutaneous volume of tissues to be
treated by electroporation, at least one of said plurality of
needle electrodes including insulated portions and a pair of
uninsulated needle portions axially separated along said needle
electrode, wherein said uninsulated needle portions form axially
separated electrodes of opposite polarity; and said insulated
portions include proximal, distal, and central insulated portions,
said proximal insulated portion being provided for insulating the
skin of the patient during an electroporation treatment, said
distal insulated portion being provided to avoid spark discharges
to an adjacent needle electrode and said central insulated portion
separating said electrodes, wherein said electrodes are disposed on
said needle electrode such that they are disposed within the
subcutaneous fat deposit during treatment; providing a generator of
high voltage pulses for applying pulsed electric field to the
electrodes, said pulses generating an electric field above the
upper electroporation limit for subcutaneous fat cells in the
volume of the subcutaneous tissue to be treated; connecting said
generator of high voltage electrical pulses with corresponding
needle electrodes placed in the deep subcutaneous fat tissue; and
applying high voltage pulses via said set of needle electrodes with
an amplitude sufficient to cause death to subcutaneous fat
cells.
7. An apparatus for reducing deep subcutaneous fat deposits in a
predetermined treatment volume beneath a predetermined area of a
patient's skin by electroporation, said apparatus comprising: a set
of needle electrodes, wherein said set of electrodes comprises: an
array of electroporation needle electrodes, said electroporation
needle electrodes being provided for applying a pulsed electric
field to the subcutaneous volume of tissues, wherein said needle
electrodes are arrayed such that each needle electrode is adjacent
to at least one needle electrode having the opposite polarity and
wherein the needle electrodes include proximal and distal insulated
portions and a central uninsulated portion configured to insulate
the skin and dispose the uninsulated portion in the subcutaneous
fat deposit; a generator of high voltage pulses for applying a
pulsed electric field to the predetermined area via said electrode
set, said pulses generating an electric field above the upper
electroporation limit for subcutaneous fat cells in the volume of
the subcutaneous tissue to be treated, and connectors connecting
said generator of high voltage electrical pulses with corresponding
electroporation electrodes.
8. An apparatus according to claim 7 wherein high voltage pulses
are electrically balanced in such a manner that in average no
direct current is passing through the treatment volume.
9. An apparatus according to claim 7 wherein high voltage pulses
are .[.rectangular.]. .Iadd.rectangularly .Iaddend.balanced.
10. Apparatus for reduction of subcutaneous fat deposits in a
predetermined treatment zone beneath a predetermined area of a
patient's skin by electroporation, said apparatus comprising: a
plurality of electrodes, wherein at least one of said electrodes is
a subcutaneous electrode configured for placement under the skin
and within the treatment zone and wherein at least one of said
electrodes is a patch electrode applied to the patient's skin; a
generator of high voltage pulses for applying a pulsed electric
field to the treatment zone via said electrodes, wherein the
applied pulses generate an electric field above the upper
electroporation limit for subcutaneous fat cells in the treatment
zone, and connectors connecting said generator of high voltage
electrical pulses with said electrodes.
11. An apparatus according to claim 10 wherein said subcutaneous
electrode is a needle electrode adapted for penetrating the skin of
a patient, said needle electrode including insulated portions and a
pair of uninsulated needle portions axially separated alone said
needle electrode, wherein said uninsulated needle portions form
axially separate electrodes of opposite polarity; and said
insulated portions include proximal, distal, and central insulated
portions, said proximal insulated portion being provided for
insulating the skin of the patient during an electroporation
treatment, said distal insulated portion being provided to avoid
spark discharaes to an adjacent needle electrode and said central
insulated portion separating said electrodes, wherein said
electrodes are disposed on said needle electrode such that they are
disposed within the subcutaneous fat deposit during treatment.
12. An apparatus according to claim 10 wherein said apparatus
includes at least a pair of subcutaneous electrodes.
13. An apparatus according to claim 12 wherein each of said at
least one pair of subcutaneous electrodes is formed on a needle
comprising proximal and distal insulated portions and wherein said
subcutaneous electrode is formed therebetween said insulated
portions on each needle.
14. An apparatus according to claim 10 and further including
plurality of subcutaneous electrodes and wherein said plurality of
subcutaneous electrodes comprises an array of electrodes each
configured for placement under the skin and within the treatment
zone, said electrodes being provided with alternating positive and
negative polarities.
15. An apparatus according to claim 10 wherein the high voltage
pulses are electrically balanced in such a manner that in average
no direct current is passing through the treatment zone.
16. An apparatus according to claim 10 wherein the high voltage
pulses are rectangularly balanced.
17. An apparatus according to claim 10 wherein said high voltage
pulses have a duration in a range of about 10 microseconds to about
10 millisecond.
18. A method for reducing the number of subcutaneous fat cells in a
predetermined treatment zone by electroporation of the cells in the
treatment zone, said method comprising: disposing at least a first
electrode in the treatment zone; disposing a second electrode on
the patient's skin in close proximity to the first electrode; and
applying high voltage electric field pulses via the first and
second electrodes with an amplitude sufficient to cause death to
subcutaneous fat cells by electroporation.
19. A method according to claim 18 wherein said at least one
treatment zone electrode is a needle including an electrode.
20. A method according to claim 18 and further including a needle,
wherein said plurality of electrodes comprises a pair of spaced
apart electrodes disposed on said needle.
21. A method according to claim 18 wherein the high voltage pulses
are electrically balanced in such a manner that in average no
direct current is passing through the treatment zone.
22. An apparatus according to claim 17 wherein the amplitude of the
electric field applied to the treated volume falls in a range of
about 20 Volt/mm to about 2000 Volt/mm.
23. An apparatus according to claim 18 wherein said high voltage
pulses have a duration in a range of about 10 microseconds to about
10 millisecond.
24. An apparatus according to claim 23 wherein the amplitude of the
electric field applied to the treated volume falls in a range of
about 20 Volt/mm to about 2000 Volt/mm.
Description
FIELD OF INVENTION
The present invention relates generally to electroporation in-vivo
and specifically to apparatus and method for reducing subcutaneous
fat deposits and/or for performing virtual face lifts and/or body
sculpturing.
BACKGROUND OF INVENTION
"Cosmetic surgery" is a phrase used to describe broadly surgical
changes made to a human body with the usual, though not always,
justification of enhancing appearance. This area of medical
practice constitutes an ever-growing industry around the world.
Obviously, where such a procedure fails to deliver an enhanced
appearance, the procedure fails to meet the desired goal. One of
the reasons that the majority of current procedures fail to deliver
upon their promise is that, for the most part, current procedures
are invasive, requiring incisions and suturing, and can have
serious and unpleasant side effects, including but not limited to
scarring, infection, and loss of sensation.
One of the more common forms of cosmetic surgery is the
"face-lift." A face-lift is intended to enhance facial appearance
by removing excess facial skin and tightening the remaining skin,
thus removing wrinkles. A face-lift is traditionally performed by
cutting and removing portions of the skin and underlying tissues on
the face and neck. Two incisions are made around the ears and the
skin on the face and neck is separated from the subcutaneous
tissues. The skin is stretched, excess tissue and skin are removed
by cutting with a scissors or scalpel, and the skin is pulled back
and sutured around the ears. The tissue tightening occurs after
healing of the incisions because less skin covers the same area of
the face and neck and also because of the scars formed on the
injured areas are contracting during the healing process.
Traditional face-lift procedures are not without potential
drawbacks and side effects. One drawback of traditional cosmetic
surgery is related to the use of scalpels and scissors. The use of
these devices sometimes leads to significant bleeding, nerve
damage, possible infection and/or lack of blood supply to some
areas on the skin after operation. Discoloration of the skin and
alopecia (baldness) are other possible side effects of the standard
cosmetic surgery. The overall quality of the results of the surgery
is also sometimes disappointing to the patients because of possible
over-corrections, leading to undesired changes in the facial
expression. Additionally, face-lift procedures require a long
recovery period before swelling and bruising subside.
The use of lasers to improve the appearance of the skin has been
also developed. Traditional laser resurfacing involves application
of laser radiation to the external layer of the skin--the
epidermis. Destruction of the epidermis leads to rejuvenation of
the epidermis layer. The drawback of the laser resurfacing
procedure is possible discoloration of the skin (red face) that can
be permanent.
Another laser procedure involves using optical fibers for
irradiation of the subcutaneous tissues, such as disclosed in U.S.
Pat. No. Re36,903. This procedure is invasive and requires multiple
surgical incisions for introduction of the optical fibers under the
skin. The fibers deliver pulsed optical radiation that destroys the
subcutaneous tissues as the tip of the fiber moves along
predetermined lines on the face or neck. Debulking the subcutaneous
fat and limited injury to the dermis along the multiple lines of
the laser treatment results in contraction of the skin during the
healing process, ultimately providing the face lift. The drawback
of the method is its high price and possibility of infection.
Electrosurgical devices and methods utilizing high frequency
electrical energy to treat a patient's skin, including resurfacing
procedures and removal of pigmentation, scars, tattoos and hairs
have been developed lately, such as disclosed in U.S. Pat. No.
6,264,652. The principle drawback of this technology is collateral
damage to the surrounding and underlying tissues, which can lead to
forming scars and skin discoloration.
Other forms of cosmetic surgery are also known. One example is
liposuction, which is an invasive procedure that involves inserting
a suction device under the skin and removing fat tissues. As with
other invasive surgical procedures, there is always a risk of
infection. In addition, because of the invasive nature of the
procedure, physicians usually try to minimize the number of times
the procedure must be performed and thus will remove as much fat
tissue as possible during each procedure. Unfortunately, this
procedure has resulted in patient deaths when too much tissue was
removed. Assuming successful removal of excess fat tissue, further
invasive surgery may be required to accomplish desired skin
tightening.
The prior art to date, then, does not meet the desired goal of
performing cosmetic surgery in a non-invasive manner while causing
minimal or no scarring of the exterior surface of the skin and at
the same time resulting in the skin tightening.
The term "electroporation" (EP) is used herein to refer to the use
of a pulsed electric field to induce microscopic pores in the
biological membranes, also commonly called a cell wall, of living
cells. The cell membrane separates the inner volume of a cell, or
cytosol, from the extracellular space, which is filled with lymph.
This membrane performs several important functions, not the least
of which is maintaining gradients of concentration of essential
metabolic agents across the membrane. This task is performed by
active protein transporters, built in the membrane and providing
transport of the metabolites via controlled openings in the
membrane. Normally, the active protein transporters, or pumps,
which routinely provide transport of various metabolic agents,
especially proteins, across the cell membrane, use either the
energy of positive ions (hydrogen or sodium ions) passing from the
positive potential of the intracellular space to the negative
potential of the cytosol, or the energy of negative ions (chlorine
ions) for movement across the membrane in the opposite direction.
This energy supply for the protein transporters is provided by
maintaining the potential difference across the membrane, which, in
turn, is linked to the difference in concentrations of sodium and
potassium ions across the membrane. When this potential difference
is too low, thousands of the active transporters find themselves
out of power.
Inducing relatively large pores in the cell membrane by
electroporation creates the opportunity for a fluid communication
through the pores between the cytosol and the extracellular space
that may lead to a drastic reduction of these vitally important
gradients of concentrations of the metabolic agents and thus a
reduction in the potential difference across the membrane.
Uncontrolled exchange of metabolic agents, such as ions of sodium,
potassium, and calcium between a living cell and the extracellular
space imposes on the cell intensive biochemical stress.
When a cell is undergoing biochemical stresses the major
biochemical parameters of the cell are out of equilibrium and the
cell cannot perform its routine functions. Invasion of very high
concentration of calcium ions through membrane pores from the
interstitial space between cells, where the calcium ion
concentration is about 100 times higher than in the cytosol, can
create such stresses by reducing the potential difference across
the membrane. In an attempt to repair itself, the cell starts
working in a damage control mode: an emergency production of actin
filaments is triggered that extend across the large pores in the
membrane in an attempt to bridge the edges of the pores, pull the
edges together, and thereby seal the membrane. In muscle cells the
calcium ion invasion may cause lethal structural damage by forcing
the cell to over-contract and rupture itself. Small pores in the
membrane created by a relatively short electric pulse can reseal
themselves spontaneously and almost instantaneously after the
removal of electric field. No significant damage to the cell is
done in this case. Contrary to that, larger pores may become
meta-stable with very long life time and cause irreversible damage.
It can be said that, depending on the number, effective diameter
-and life time of pores in the membrane, electroporation of the
cell may result in significant metabolic or structural injury of
the cell and/or its death. The cause of cell death after
electroporation is believed to be an irreversible chemical
imbalance and structural damage resulted from the fluid
communication of the cytosol and the extracellular environment.
Below a certain limit of the electric field no pores are induced at
all. This limit, usually referred to as the "lower EP limit" of
electroporation, is different for different cells, depending, in
part, on their sizes in an inverse relationship. That is, pores are
induced in larger cells with smaller electric fields while smaller
cells require larger electric fields. Above the lower EP limit the
number of pores and their effective diameter increase with both the
amplitude and duration of the electric field pulses.
Removing the electric field pulses enables the induced pores to
reseal. This process of resealing of the pores and the ability of
the cell to repair itself, discussed briefly above, currently is
not well understood. The current understanding is that there is a
significant range of electric field amplitudes and pulse durations
in which cells survive electroporation and restore their viability
thereafter. An electroporated cell may have open pores for as long
as many minutes and still survive. The range of electric field
amplitudes and pulse durations in which cells survive is
successfully used in current biomedical practice for gene transfer
and drug delivery inside living cells.
Nevertheless, the survivability of electroporated cells is limited
As the electric field amplitude and/or duration of pulses,
increases, this limit, usually referred to as the "upper EP limit"
of electroporation, is inevitably achieved. Above the upper EP
limit, the number and sizes of pores in the cellular membrane
become too large for a cell to survive. Multiple pulses cause
approximately the same effect on the cells as one pulse with a
duration equal to the total duration of all applied pulses. After
application of an electrical pulse above the upper electroporation
limit the cell cannot repair itself by any spontaneous or
biological process and dies. The upper EP limit is defined by the
combinations of the amplitudes of electric field and pulse
durations that cause cellular death.
The vulnerability of cells to electroporation depends on their
size: the larger the cell, the lower the electric field and
duration of a pulse capable of killing it. If cells of different
sizes are exposed to the same electric field, the largest cells
will die first. Thus, this ability of electroporation to
discriminate cells by their sizes may be used to selectively kill
large cells in the human body.
In the previously referred to application for U.S. patent
application entitled "Apparatus and Method for Reducing
Subcutaneous Fat Deposits, Virtual Face Lift and Body Sculpting by
Electroporation", Ser. No. 09/931,672, filed Aug. 17, 2001, an
apparatus and method for performing non-invasive treatment of the
human face and body by electroporation in lieu of cosmetic surgery
is disclosed. The apparatus comprises a high voltage pulse
generator and an applicator having two or more electrodes utilized
in close mechanical and electrical proximity with the patient's
skin to apply electrical pulses thereto. The applicator may include
at least two electrodes with one electrode having a sharp tip and
another having a flat surface. High voltage pulses delivered to the
electrodes create at the tip of the sharp electrode an electric
field high enough to cause death of relatively large subcutaneous
fat cells by electroporation. Moving the electrode tip along the
skin creates a line of dead subcutaneous fat cells, which later are
metabolized by the body. Multiple applications of the electrode
along predetermined lines on the face or neck create shrinkage of
the skin and the subcutaneous fat reduction under the treated
area.
The electroporation in-vivo, employed in the disclosed method is a
non-invasive treatment of subcutaneous fat, which, as was
previously described before, involves application of high amplitude
electric pulses between external electrodes to cause death by
electroporation of the subcutaneous fat cells. Fat cells, being
typically larger than other cells of the body, are more easily
killed by electroporation treatment than are smaller lean muscle
cells. The electric field, applied to the external electrodes, is
efficient for cell killing in the subcutaneous layer of fat tissue
directly under the skin. However, the amplitude of the field
significantly decreases with increasing the depth of the deposits
of fat cells. The deeper penetration of the electric field may be
achieved by increasing the distance between electrodes with
simultaneous increase in the operating voltage. This approach,
though, leads to concomitant increase of the volume that is treated
by electroporation. Occasionally, during such cosmetic and body
sculpting procedures as described above, a small volume of deep
subcutaneous fat deposit must be treated. The non-invasive method
of treating subcutaneous tissue by electroporation as described in
the earlier referenced patent application, in which the high
voltage pulses are applied to the external electrodes, is sometimes
difficult to apply to deep fat deposits especially when a fine
spatial resolution is required
It would be desirable to have available an apparatus and a method
for electroporation treatment to reduce deep fat deposits by
allowing deep localized application of the electroporation pulses
that can provide high spatial resolution of the body sculpting.
Preferably, such apparatus and methods would also be minimally
invasive.
SUMMARY OF THE INVENTION
The present invention provides an apparatus and method for creation
of a controlled electroporation injury to deep subcutaneous fat
tissues that, with the healing that follows, leads to permanent
loss of the fat cells in the treated tissue. According to present
invention an electric field capable of killing fat cells in deep
subcutaneous deposits may be applied by a set of needle electrodes,
configured for placement deeply under the skin. An apparatus
according to the current invention comprises a voltage pulse
generator, an applicator with two or multiple electrodes of
different shapes and sizes, and a cable connecting the electrodes
to the pulse generator. The pulse generator produces a sequence of
high voltage pulses of predetermined amplitude, duration and number
to cause necrosis in a treated area of the subcutaneous tissue.
A method of weight loss and body sculpturing in accord with the
present invention comprises application of electrical pulses to the
electrodes positioned under the skin in a treatment area of the
subcutaneous fat tissue. The amplitude, duration and number of
applied pulses are selected to cause necrosis of fat cells at a
predetermined distance around the needles in the subcutaneous
tissue. During the treatment a number of sites in a predetermined
pattern are exposed to electroporation. Later, during the healing
process the treated area contracts as the electroporated cells die
and are metabolized by the body, thus reducing volume of fat tissue
and providing desired change of body contours. The injury to the
tissues made by electroporation is very selective, targeting only
large fat cell and not damaging the epidermis, the most external
layer of the skin. As a matter of fact, in accordance with the
current invention, the electrical field is applied only to the deep
subcutaneous fat deposits, no electric field is applied to the skin
of the patient.
The present invention, as well as its various features and
advantages, will become evident to those skilled in the art when
the following description of the invention is read in conjunction
with the accompanying drawings as briefly described below and the
appended claims. Throughout the drawings, like numerals refer to
similar or identical parts.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of an electroporation system for
treatment of deep subcutaneous fat deposits.
FIG. 2 shows time diagrams for high voltage pulses during EP
treatment wherein FIG. 2a illustrates unipolar pulsing and FIG. 2b
illustrates bipolar pulsing.
FIG. 3 illustrates a one-needle applicator with two electrodes.
FIG. 4 illustrates an embodiment of an applicator comprising one
needle in combination with an external patch electrode wherein FIG.
4a provides a plan view and FIG. 4b provides a cross-sectional view
taken along viewing plane 4b--4b.
FIG. 5 illustrates an embodiment of the applicator comprising an
array of needle electrodes.
FIG. 6 illustrates in orthogonal views in FIGS. 6a and 6b an
embodiment of the applicator comprising needle electrodes without
insulated parts.
DESCRIPTION OF THE INVENTION
FIG. 1 shows schematically an electroporation system 100 for
in-vivo treatment of deep subcutaneous fat deposits. The system 100
includes a high voltage electroporation pulse generator 101
connected by an appropriate connector 102 to an applicator 103.
Applicator 103 may include a handle 104 and a pair of needle 120
and 122 extending therefrom. Handle 104 may be used by the operator
for the safe and efficacious placement of the needles 120 and 122
in a selected-for-treatment anatomical site. Needles 120 and 122
may include proximal insulated portions 124 and 126, respectively,
central uninsulated portions 128 and 130, respectively, and distal
insulated portions 132 and 134. Preferably, distal portions 132 and
134 includes sharpened ends or tips 136 and 138, respectively.
As illustrated in the Figure, an operator of system 100 will use
handle 104 to push the tips 136 and 138 through the skin 150 of the
patient into a deep subcutaneous fat deposit 152. The sharpened
tips 136 and 138 facilitate penetration of the skin 150 and fat
tissue 152 while minimizing pain or serious discomfort to the
patient. Insulated proximal portions 124 and 126 of needles 120 and
122, respectively, provide electrical insulation from the skin 150
during an EP treatment. That is, this insulation prevents a current
flow from the needles 120 and 122 through the skin and with it an
associated discomfort of the patient. Similarly, the insulated
distal portions 132 and 134 of needles 120 and 122 helps to avoid
spark discharges between the tips during high voltage
electroporation pulsing.
Central portions 128 and 130 form the electrodes for the system 10,
which as noted are uninsulated. The electrodes 128 and 130 are in
close electrical contact with the surrounding tissue 152 and
provide a pulsed electrical field, as indicated by shown by arrows
160, to the treatment zone 162 between and around electrodes 128
and 130, as indicated by dotted line 162. It will be understood
that the treatment zone is actually a three dimensional zone
extending in all directions from the electrodes 128 and 130.
The larger the diameter of the cells or the higher applied voltage,
the larger treatment zone 162 will be where the cells are actually
killed. It should be mentioned that not all cells die at any point
of the treatment zone. The smaller fat cells will survive. As was
mentioned early, cell killing by electroporation is selective on
the cell size and the upper EP limit is higher for small cells.
Small fat cells, for which applied electric field is below the
upper electroporation limit, will survive any reasonable number of
electric pulses without any morphological or functional damage and
will stay in the tissue. Also, there is no electroporation
treatment for the tissues interfacing the insulated parts of the
needles.
A computer 170 connected by an appropriate connector 172 to EP
generator 101, may be provided to control the whole procedure of EP
treatment: the predetermined amplitude, duration, and number of EP
pulses supplied to the electrodes 128 and 130. The EP pulses may be
applied with a repetition rate of about 1 to about 50 Hz and may
have a current peak of about 0.5 to about 10 A depending on the
size and shape of electrodes. Generally, the voltage of the EP
pulses can be in the range of about 50 V to about 5000 V with a
duration from about 10 microseconds to about 10.0 milliseconds
depending on the location of the treated segment of the body, the
sizes and shapes of the electrodes, and the distance between the
electrodes. Regardless of the possible configuration of the
electrodes and the voltages applied to the treatment volume, the
voltage applied to an individual subcutaneous fat cell should fall
in the range of about 2 to about 10 V per cell to be able to kill
it.
To achieve successful cell killing by electroporation the electric
field applied to the treated volume of cells must be above the
upper EP limit for the cells. The probability of cell killing
increases if longer or multiple pulses are employed.
According to present invention high voltage pulses of different
waveforms may be used for the EP treatment. The pulses may be
rectangular or exponential in shape, be unipolar (positive or
negative only) or bipolar (positive and negative). Bipolar
rectangular pulses are known to be very efficient in cell killing
by electroporation. This is because both directions of the
electrical field, positive and negative, are equally efficient in
creating pores in cellular membranes, and the electric field
strength, contrary to the exponential pulses, stays high during the
whole pulse. The efficiency results because electroporation is a
process related to the difference in the energy of the porous and
non-porous membrane in the presence of an electric field. The
energy difference depends on the square of the amplitude (or
strength) of the electric field (i.e., E.sup.2) and does not depend
on the sign or polarity (+ or -) of the electric field.
From a practical stand point, however, applying balanced pulses
during in-vivo electroporation treatment has one important
advantage. Contrary to unipolar pulsing, that carries a direct
current component into the treated tissue and creates undesired
electrolytic effects on the interface of the electrodes and
tissues, bipolar pulsing is free from these drawbacks. With bipolar
pulsing of the field, problems such as metal depositions from the
electrodes or chemical decomposition of tissue during treatment are
largely if not completely avoided.
These advantageous properties of balanced pulses, namely, high
efficiency in cell killing and freedom from electrolytic effects,
make using rectangular bipolar balanced pulses a preferred mode for
electroporation pulsing in the current invention. Technically,
balancing of two pulses of the opposite polarities may be easily
achieved by using a pulse generator having a direct current
blocking capacitor electrically coupled in series to the needle
electrodes.
In FIGS. 2a and 2b plots of high voltage EP pulses against time are
shown. In FIG. 2a the upper curve shows a plot of rectangular
balanced pulses, the preferred embodiment and the lower curve shows
exponential balanced pulses. FIG. 2b depicts rectangular and
exponential unipolar pulses in the upper and lower curves,
respectively.
In FIG. 3 another embodiment 300 of the needle applicator is shown.
Needle applicator 300 comprises a single needle 310 with two
axially separated electrodes 328 and 330 of opposite polarity
insulated from each other and separated by insulator 308. The
needle may be made of a hollow tube carrying inside two conductors
connecting electrodes 328 and 330 via cable 302 to the output of
the EP generator, not shown in the figure. Proximal end 325 of the
needle 310 is covered with an insulation layer to protect the skin
of the patient during treatment from an electric current and
discomfort associated with it. To avoid sparking from the distal
end 333 of the applicator the needle 310 may be made of insulating
material or of a metal piece electrically insulated from the
electrodes 328 and 330. Additionally, distal end 333 may have a
sharp tip 337.
The electric field between electrodes 328 and 330 is shown by lines
360. Dotted lines 362 delineate the treatment zone, where the
electric field is the highest and where actual killing cells by
electroporation occurs.
Yet another embodiment 400 of the needle applicator is shown in
FIG. 4 in two substantially orthogonal views, namely FIGS. 4a and
4b. Applicator 400 comprises a needle 410 with an electrode 428
combined with a patch electrode 430. Patch electrode 430 is placed
on the skin 450 of the patient near the treatment site, which is
delineated by a dotted line 462. Needle 410 may include a sharp tip
436 and insulated proximal and distal portions 442 and 433 on
either side of electrode portion 428 of needle 410. The electrical
field lines generated between electrodes 428 and 430 are indicated
by lines 460. High voltage EP pulses during treatment are delivered
to the electrodes 428 and 430 via appropriate conductors 454 and
455, respectively, which are connected to the connector 402 coupled
to the output of the EP generator 101, not shown in the FIG. 4.
During use of the needle applicator 400, the electroporation
leading to cellular death occurs only around the conductive
surface, i.e., electrode 428, of the needle placed in the tissue.
No electroporation takes place near the patch electrode 430 on the
skin because the value of the electric field near its surface is
less than the upper EP limit. FIG. 4b shows cross section of the
applicator. Dotted line 462 delineates the treatment zone around
the electrode 428 where the fat cells are killed.
FIG. 5 shows yet another implementation 500 of a needle applicator
in accord with the present invention. Applicator 500 comprises a
handle 504 supporting a needle frame 505. Needle frame 505 supports
a plurality of needles 520 of one polarity (positive) and a
plurality of needles 522 including an electrode of the other
polarity (negative), with each needle of one polarity being
adjacent to one or more needles of the other polarity. Handle 504
is connected via connector 502 to the output of the EP generator
101 (not shown in the Figure). The needles 520 and 522 in the
needle array alternately have positive and negative polarity. The
needles 520 and 522 may include a proximal insulated portion 524
and 526, central electrode portions 528 and 530, and distal
insulated portions 536 and 538 respectively. Each needle 520 and
522 will also preferably include sharp tip 536 and 538. For EP
treatment of subcutaneous deposits the needles are placed
preferably normally to the skin. One of benefits of this
configuration is that the tissue electroporation occurs in thin
cylindrical layers around the electrodes and later, during healing
process, macrophages from nearby blood vessels will travel a
shorter distance to the damaged cells. Thus, this configuration may
accelerate the disposal of the dead fat cells.
Yet another implementation of the needle applicator is shown in
FIG. 6. Applicator 600 may include a handle 604 and a pair of
needle 620 and 622 extending therefrom. Handle 604 may be used by
the operator for the safe and efficacious placement of the needles
620 and 622 in a selected-for-treatment anatomical site. The
sharpened tips 636 and 638 facilitate penetration of the skin 650
and fat tissue 652 while minimizing pain or serious discomfort to
the patient. In this implementation of the current invention the
whole needles 620 and 622 perform function of electrodes; that is,
the needles 620 and 622 do not include insulated portions as in the
previously described embodiments. Via an appropriate connector 602
needles 620 and 622 are connected to the EP generator (not shown in
the Figures) providing high voltage pulses during treatment.
Electric field lines between electrodes 620 and 622 are shown by
arrows 660. Dotted line 662 shows the treatment area of the fat
tissue 652 where electroporation actually kills fat cells.
Needle electrode diameters may fall in a range of about 0.3 mm to
about 1.0 mm, which corresponds to the standard of minimally
invasive size. The distance between adjacent needles may be in a
range of several mm to several cm. Applied voltage, depending on
the distance between needles and the size of the fat cells to be
killed, may vary in a wide range from about 100 V to several
hundreds and even thousands of volts. In any case the resultant
electric field applied to the treated fat cells must be above their
upper electroporation limit, or about 2 to about 10 V per cell. The
electroporation pulses during treatment may be applied
simultaneously to all electrodes or in a sequence of sets of two to
several electrodes throughout the whole treated area. The number of
pulses per treatment of a selected site may vary from several
pulses to several tens of pulses. Preferred duration of the pulses
is from about 10 microseconds to about 10 milliseconds.
A method for electroporation treatment of deep subcutaneous fat
deposits comprises providing a high voltage pulse generator for
generation EP pulses and a needle applicator. The needle applicator
or needle applicator and pad electrode may be placed by a physician
in an anatomically selected site of treatment under ultrasound or
other type of imaging guidance. After the needle placement a
sequence of high voltage EP pulses is applied to the electrodes.
The electrodes may be placed in plurality of treatment sites in
accordance with a treatment plan developed by a physician.
Sequences of the high voltage EP pulses are repeatedly applied to
the electrodes. After a session of electroporation treatment the
remnants of fat cells and released lips will be metabolized and
removed by the patient's body over about a two week period. A
subsequent electroporation treatment can then be performed with new
treatment sites selected for the electroporation treatment. In this
manner, then, a patient's body can be sculpted as desired.
The present invention has been described in language more or less
specific as to the apparatus and method features. It is to be
understood, however, that the present invention is not limited to
the specific features described, since the apparatus and method
herein disclosed comprise exemplary forms of putting the present
invention into effect. For example, while the needles have been
described as having sharp tips, blunted end needles may also be
used. Additionally, as indicated in the Figures, insulation may be
used on the needles in some embodiments, but not others. The
invention is, therefore, claimed in any of its forms or
modifications within the proper scope of the appended claims
appropriately interpreted in accordance with the doctrine of
equivalency and other applicable judicial doctrines.
* * * * *