WO1998040123A1

WO1998040123A1 - Endometrial heating with visible light

Info

Publication number: WO1998040123A1
Application number: PCT/US1998/004892
Authority: WO
Inventors: Donald L. Alden; Arnold J. Kresch
Original assignee: Femrx, Inc.
Priority date: 1997-03-12
Filing date: 1998-03-12
Publication date: 1998-09-17
Also published as: JP2001514564A

Abstract

The invention provides a method and apparatus for treating a lining of a hollow body organ (U1). The method comprises generating electromagnetic radiant energy, wherein at least a significant portion of the radiant energy comprises light energy within the visible spectrum. The radiant energy is diffused from within the hollow body organ through a gas, and onto the lining of the hollow body organ, so that the visible light energy heats at least a significant portion of the lining.

Description

ENDOMETRIAL HEATING WITH VISIBLE LIGHT

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the use of radiant energy for therapy of internal tissues, and m particular, provides a method and system for using visible light to heat the endometrium of the uterus and other hollow body organs .

Excessive uterine bleeding is a relatively common condition which effects a large percentage of women at some time during their lifetime. While a hysterectomy is an effective procedure for relief of excessive bleeding m extreme cases, many women prefer less drastic procedures, such as removing and/or cauterizing the lining (endometrium) of the uterus .

A large variety of therapeutic procedures nave been proposed for endometrial cautery and/or removal . The use of electrosurgery to cut and cauterize the uterine tissues is known and relatively effective, but can be somewhat time consuming. A number of alternative treatments have also been proposed, including caustic chemicals, laser ablation, and the application of heated liquids. The acceptability of caustic chemicals nas been limited by the dangers of contact with tissues outside the target area, as well as by the potential for injurious overexposure . Although laser ablation has been used to burn away the uterine lining, the effective area of lasers at reasonable power settings s relatively small, so that such a procedure requires a very long time to treat the entire endcmetnum. More recently, it has been proposed to apply heated liquids (typically water or a saline solution) to uniformly elevate the temperature of the endometrium. While these proposals provide a relatively rapid procedure with a fairly uniform therapeutic temperature, the systems for applying these methods tend to be quite complex. Specifically, these systems generally include mechanisms to protect the patient from excessive fluid pressures and from fluid contamination, and typically provide fluid circulation within the cavity, all while avoiding heating of tissues outside the target area.

In light of the above, it would be desirable to provide alternative systems and methods for removing and/or cauterizing the lining of the endometrium. It would be preferable if these systems and methods were adaptable to the physiology of a wide variety of patients, without requiring a time consuming therapeutic procedure. It would be ideal if these treatments for the endometrium could be provided in a minimally invasive outpatient procedure, with enhanced safety and control over the affected tissues, and with a reduced danger of perforating the uterus to inflict injury on the surrounding organs .

2 : Description of the Background Art U.S. Patent No. 5,478,339, describes an intrauterine device for laser light diffusion, and a method for its use.

U.S. Patent No. 5,449,354, also describes a device for treating the interior of body cavities with laser energy.

U.S. Patent No. 4,784,132, describes a method and apparatus for laser treatment of body lumens, particularly for treating occluded body lumens such as blood vessels. U.S. Patent No.

5,517,005, describes a visible light and infrared cooking apparatus for use in food preparation.

U.S. Patent No. 4,612,938, describes a method for illuminating body cavities. U.S. Patent No. 5,405,369, describes photo chemical ablation of gastrointestinal tissue. U.S. Patent No. 5,536,265, describes a light diffuser and a method for its manufacture. U.S. Patent No. 5,298,026, describes a method and apparatus for laser treatment of tumors. U.S. Patent Nos . 4,998,930 and 5,125,925, describe mtracavity laser catheters and photo therapy methods .

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a method for treating a lining of a hollow body organ. The method comprises generating electromagnetic radiant energy, wherein at least a significant portion of the radiant energy comprises light energy within the visible spectrum. The radiant energy is diffused from within the hollow body organ and onto the lining of the hollow body organ, so that the visible light energy heats at least a significant portion of the lining.

Visible light will often heat the tissue to a predetermined target depth, particularly for treating a lining of the uterus. Optionally, the radiant energy will further comprise a penetrating energy such as infrared or microwave energy. Visible light can then heat a portion of the lining adjacent a lining surface, while the penetrating energy will direct heat more deeply below the surface. In some embodiments, the hollow body organ will be distended by pressurizing a gas or liquid therein.

In another aspect, the present invention provides a method for treatment of excessive uterine bleeding. The method comprises generating electromagnetic radiant energy a significant portion of which comprises light energy within the visible spectrum. The radiant energy is diffused from within the uterus to the endometrium. Specifically, the visible light energy heats at least a significant portion of the endometrium. The diffusing and heating step is terminated when the heated endometrium portion reaches a temperature within a predetermined endometπal ablation range. In some embodiments, the diffuser probe can be manipulated within the uterus to manipulate folds of the endometrium, so that substantially all of the endometrium is treated. In another aspect, the present invention provides an optical hyperthermia diffuser probe comprising an optical cable having a proximal end and a distal end. The optical cable is capable of transmitting optical energy within the visible spectrum to effect heating of the lining of a hollow body organ. At least one diffuser extending distally from the fiber optic cable is adapted to diffuse the optical energy radially to the lining from within the hollow body organ. Preferably, the probe includes a plurality of diffusers which are resiliently biased to splay laterally away from each other. By selectively deploying such resilient diffuser structures, the geometry of the diffuser can be varied to adapt to the specific patient's physiology.

In another aspect, the present invention provides an optical hyperthermia diffuser probe. The probe comprises a fiber optic cable having a proximal end and a distal end, the cable being capable of transmitting a therapeutic optical energy. A plurality of diffusers extend distally from the fiber optic cable. The diffusers are capable of transmitting the optical energy distally when they are aligned axially, but are adapted to diffuse the optical energy radially when the diffusers are laterally separated from each other. A sheath is slidably disposable over at least a portion of the diffuser to align that portion together. Hence, an effective diffuser length can be varied by changing the position of the sheath, allowing the probe to accommodate users having different uterine geometries.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 s a perspective view of a distal end of a resilient diffuser probe, according to the principles of the present invention.

Fig. 2 is a schematic illustration of a system for heating the endometrium using radiant energy which is within the visible spectrum, which system includes the probe of Fig. 1. Figs. 3A and B illustrate the use of the probe of Fig. 1 for heating the endometrium of patients having differing uterine geometries, by selectively extending resilient diffusers beyond a sheath of the probe.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Referring first to Fig. 1, a visible light endometπal ablation probe 10 generally comprises an elongate body having a proximal orientation 12 and a distal orientation 14. A pair of resilient diffusers 16, 18 are extendable distally beyond a sheath 20. Although the probe of the present invention will generally be described with reference to a pair of resilient diffusers, probe structures having three or more resilient diffuser ends are also encompassed by the present invention.

Each of diffusers 16, 18 comprises a half cylinder 22 and a spherical end 24. The half cylinders are resiliently biased to splay laterally apart. Preferably, the half cylinders are sufficiently flexible so as to be axially restramable by sheath 20. When the half cylinders extend distally beyond the sheath, they splay outward as shown to substantially conform to the "Y" shape of the uterus. Ideally, the diffusers splay resiliently outward with force less than that which would impose blunt injury on the uterine lining, so that the diffusers may be safely radially restrained by the surrounding body cavity.

Advantageously, portions 26 of diffusers 16, 18 proximal of the distal end of sheath 20 combine to provide a wave guide having a cylindrical cross section. Such a cylindrical cross section enhances the ability of wave guide 26 to efficiently transmit radiant energy. In other words, the two diffusers together, optionally m combination with surrounding sheath 20, efficiently transmit light in the visible spectrum distally through the sheath. Proximally of diffusers 16, 18, wave guide 26 will typically be coupled to a more conventional high power optical cable, such as a bundle of optical fibers. The portions 28 of diffusers 16, 18 which extend distally beyond sheath 20 will diffuse the light radially from their separated, semi-circular cross sections. To tailor the light diffusion pattern surrounding resilient diffusers 16, 18, and to enhance transmission along the combined wave guide, the index of refraction of the diffuser structures can be varied both axially and radially. Light which is transmitted distally through the combined portions 26, and through the independent distal portions 28 is diffused through spherical ends 24, generally in an even spherical manner.

The structure of each of diffusers 16, 18 may be formed from a large number of individual fibers, or may alternatively comprise a monolithic polymeric structure having the desired light propagation characteristics. For example, suitable diffuser materials and/or structures are available from Rare Earth Medical, Inc., of West Yarmouth, Massachusetts. Alternatively, resilient diffusers 16, 18 may be fabricated by bundling commercially available glass or plastic fibers into a shaft of the desired cross section. At the diffuser end, the fibers are splayed to produce the desired optical power distribution. The fibers may also be woven or knit to induce light leakage, and the optical power distribution can be varied by varying the density and tightness of the weave or knit . The prepared fibers can then be bonded with a matrix of silicone elastomer or the like.

Sheath 20 may comprise a simple polymeric or metallic sheath having sufficient hoop strength to restrain resilient diffusers 16, 18 in a straight configuration. As was mentioned above, the sheath may optionally include a reflective inner surface and/or a material having an index of refraction which promotes the transmission of radiant energy distally through the combined wave guide 26 formed by resilient diffusers 16, 18. In some embodiments, the space between the sheath and the resilient diffuser will provide a gas flow path for distention of the uterine cavity. Sheath 20 will often include a proximal housing for connection of the light source, gas supply, diffuser extension mechanism, and the like. Sheath 20 may also optionally include an inflatable annular balloon, a local increase in outer diameter, or some other mechanism to facilitate sealing of the outer surface of sheath 20 against the cervix, particularly when distention of the uterus is desired. Referring now to Fig. 2, a visible light endometrial ablation system 30 includes probe 10 having a proximal housing 32. Schematically illustrated features of the proximal housing include a diffuser extension mechanism 34, a coupling for visible light source 36, a coupling for a temperature sensor system 38, and a distention gas input port 40.

Visible light source 36 will generally provide electromagnetic radiant energy which includes at least a significant portion of the total energy within the visible spectrum. Generally, visible light energy provides somewhat limited penetration, typically heating tissue at or near its surface. Often times, the targeted tissue will e within about 1 cm. of the internal surface of the uterus, so that the penetration of visible light is quite adequate. In contrast, infrared and microwave energy is able to penetrate significant distances through the tissue, and can result in heating at a significant depth below the exposed lining. Therefore, visible light provides a significant advantage in safety as compared to infrared and microwave energy, as the risk of hypothermia of tissues below the targeted endometrium is significantly lessened. Nonetheless, it may desirable to provide electromagnetic radiant energy which is a combination of radiant energy within the visible spectrum, together with a predetermined amount of a more penetrating energy such as infrared and/or microwave energy (the latter normally having a separate transmission structure) to treat tissues both at their surface, and to a desired depth below the exposed lining. Ideally, the relative amounts of visible and penetrating radiant energy will be selectively controllable. Generally, light source 36 will provide sufficient energy to heat a substantial portion of the endometrium to a predetermined hypothermia range, typically over a temperature of approximately 80°C and preferably to a temperature of approximately 100°C. Heating times will depend on the size of the treatment area, on the depth to which tissue will be heated, on the specific combination of visible and penetrating electromagnetic energy, on any heat transfer to a distention medium, and on the power delivered by the light source and cable. Generally, light source 36 will comprise a quartz halogen, xenon, or other light source with spectral characteristics selected for a combination of tissue penetration and surface heating. One lamp structure which provides a significant radiant energy within the visible light spectrum is described in U.S. Patent No. 5,517,005, the full disclosure of which is incorporated herein by reference.

Temperature sensor system 38 may optionally include thermocouples or other temperature sensors built into the ends of resilient diffusers 16, 18. In some embodiments, the temperature sensor system may monitor and analyze the reflected light traveling back through the combined wave guide to determine the temperature of the exposed endometrium. It should be understood that temperature sensor system 38 will often provide feedback to light source 36. Such feedback facilitates the heating of the endometrium to a predetermined ablation temperature, or the maintaining of such an endometrial ablation temperature for a predetermined time. Carbon dioxide, or some other biocompatible gas, will often be introduced through distention port 40 to distend the uterus. Such a distention gas can flatten the folds within the uterus to enhance uniformity of exposure, but avoids the thermal convectivity and fluid born contaminants of water or saline distention. Alternatively, water or saline distention may also be effective. In some embodiments, folds in the uterine lining may be treated by gently rotating the probe to open and expose the endometrial folds with the resilient diffuser structures.

While the illustrated embodiment of the probe does not include a scope for visual direction of the endometrial ablation process, it should be understood that the sheath can be enlarged to include such a scope, either within the main lumen, or in a separate dedicated lumen. In some embodiments, the cross section of the diffuser may be modified to accommodate such a scope .

A method for endometrial ablation using the probe of Fig. 1 will be described with reference to Figs. 3A and B. Typically, probe 10 will be positioned prior to transmitting therapeutic radiant energy through diffusers 16, 18. In some embodiments, the sheath 20 will be introduced transcervically prior to introducing the diffusers into the lumen of the sheath. An obturator, optionally including a scope, may be used to facilitate transcervical positioning of the sheath. In other embodiments, the rounded ends of the diffusers will combine to form an atraumatic end for advancement of the sheath.

In some embodiments, sheath 20 will form a seal against cervix C. As described above, an annular balloon mounted on the sheath or a simple tapered shoulder (at which the sheath increases in diameter proximally) may facilitate sealing. Once the sheath is sealed across the cervix, a distention gas may be supplied through the sheath to distend the uterine cavity, exposing any folds in the endometrium. Alternatively, sheath 20 may be significantly smaller in diameter, and folds may be exposed by manipulation of the endometrial surface using resilient diffusers 16, 18. In such embodiments, the presence of a scope, preferably incorporated into sheath 20, will facilitate this manual manipulation of the uterine lining.

As can be understood by comparing uterus Ul of Fig. 3A with uterus U2 of Fig. 3B, the resilient diffuser structures of probe 10 allow a standard size probe to be readily adapted to significantly differing uterine volumes. Specifically, the "Y" shape of the diffuser largely conforms to the shape of the uterus, allowing the light from the diffuser to expose and treat the tubul os and fundus . Advantageously, varying uterine widths can be accommodated by the flexibility of the diffusers, which may be safely restrained by the sides of the uterus during the procedure. Additionally, varying uterine lengths can be accommodated by extending the diffusers to a selected length beyond the distal end of sheath 20. Thus, a large range of anatomy can be treated by the standard device illustrated. Positioning of the device is aided by its deployed shape, which will tend to self align with the generally elliptical cross section at the top of the uterus .

As described above, electromagnetic radiant energy which includes a significant visible spectrum component is transmitted through the sheath and diffused by diffusers 16, 18. Advantageously, the visible light energy heats a significant portion of the endometrium, providing heating at or near the exposed endometrial surface. This heating may be terminated immediately once the endometrium reaches a temperature within a predetermined endometrial ablation range, or the endometrium may be maintained at an elevated temperature for some predetermined amount of time to effect therapy. As described above, the diffusers may incorporate temperature sensors for contact measurements of the endometrial temperature, or reflected energy transmitted back through sheath 20 may be analyzed to provide this information. Advantageously, the relatively large, continuous diffusing surface of diffusers 16, 18 minimizes any local "hot spots", such as where the diffuser surface touches the uterine lining. Thus, this large diffuser surface facilitates direct manipulation of folds in the endometrium to enhance exposure during the heating process.

Generally, between about 5 and 150 watts of radiant heating energy will be transmitted through the diffuser during therapy, typically for a period between 0.25 and 10.0 minutes. Of this total radiant energy, between about 40 and 90% will typically be radiant light energy within the visible spectrum. In the exemplary embodiment shown, the sheath will have an outer diameter in the range between about 2.0 and 9.0 mm, while the diffusers will be extendable from the sheath by a distance in the range between about 1.0 and 10.0 cm. Such a structure will provide an effective endometrial ablation therapy procedure with a heating time in the range between about 0.25 and 10.0 minutes. While the exemplary embodiment of the present invention has been described in some detail, for purposes of clarity and understanding, a variety of changes, modifications, and adaptations will be obvious to those of skill in the art. Therefore, the scope of the present invention is limited solely by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method for treating a lining of a hollow body organ, the method comprising: generating electromagnetic radiant energy, wherein at least a significant portion of the radiant energy comprises light energy within the visible spectrum; and diffusing the radiant energy from within the hollow body organ and onto the lining of the hollow body organ so that the visible light energy heats at least a significant portion of the lining.

2. A method as claimed in claim 1, wherein the visible light heats a portion of the lining adjacent a lining surface, and wherein the radiant energy further comprises a penetrating energy selected from the group consisting of infrared and microwave energy.

3. A method as claimed m claim 1, further comprising terminating the diffusing and heating step after the heated lining portion reaches a temperature within a predetermined hyperthermia range.

4. A method as claimed m claim 1, further comprising distending the hollow body organ with a gas or liquid.

5. A method as claimed in claim 1, further comprising varying a diffuser geometry based on the geometry of the hollow body organ to enhance the size of the heated lining portion.

6. A method for treatment of excessive uterine bleeding, the method comprising: generating electromagnetic radiant energy, wherein at least a significant portion of the radiant energy comprises light energy within the visible spectrum; diffusing the radiant energy from within the uterus to the endometrium so that the visible light energy heats at least a significant portion of the endometrium; and terminating the diffusing and heating step after the heated endometrium portion reaches a temperature within a predetermined endometrial ablation range.

7. A method as claimed m claim 6, further comprising distending the uterus with a gas or liquid while heating.

8. A method as claimed in claim 6, further comprising varying a diffuser length and width based on the geometry of the uterus .

9. A method as claimed m claim 8, further comprising rotating the diffuser probe within the uterus to manipulate folds of the endometrium.

10. A method as claimed m claim 6, further comprising monitoring uterine wall temperatures by analyzing the radiant energy reflected by the endometrium.

11. An optical hyperthermia diffuser probe comprising: an optical cable having a proximal end and a distal end, the optical cable capable of transmitting optical energy within the visible spectrum to effect heating of a lining of a hollow body organ; at least one diffuser extending distally from the fiber optic cable, the at least one diffuser adapted to diffuse the optical energy radially to the lining from within the hollow body organ.

12. An optical diffuser probe as claimed m claim 11, further comprising a plurality of diffusers which are resiliently biased to splay laterally away from each other, and further comprising a sheath slidably disposable over the diffusers to releasably restrain the diffusers together for introduction into the hollow body organ.

13. An optical diffuser probe as claimed in claim 12, wherein each of the flexible diffuser portions defines a semicircular cross section having a substantially flat side, and wherein the sheath restrains the flat sides against each other.

14. An optical diffuser probe as claimed in claim 12, wherein the two diffusers form a Y-shape having a width and a length which can be varied by changing the axial position of the sheath.

15. An optical hyperthermia diffuser probe comprising: a fiber optic cable having a proximal end and a distal end, the fiber optic cable capable of transmitting therapeutic optical energy; a plurality of diffusers extending distally from the fiber optic cable, the diffusers capable of transmitting the optical energy distally when axially aligned, the diffusers adapted to diffuse the optical energy radially when laterally separated; a sheath slidably disposable over at least a portion of the diffusers to align the at least a portion of the diffusers together.

16. An optical hyperthermia diffuser probe as claimed in claim 15, wherein an effective width and length of the diffuser varies with the axial extension of the diffuser from the sheath to accommodate users having differing uterine volumes .