Method and system for photoselective vaporization for gynecological treatments

Abstract

A method for photoselective vaporization of uterine tissue includes delivering laser radiation to the treatment area on the tissue, via an optical fiber for example, wherein the laser radiation has a wavelength and irradiance in the treatment area on the surface of the tissue sufficient because vaporization of a substantially greater volume of tissue than a volume of residual coagulated tissue caused by the laser radiation. The laser radiation is generated using a neodymium doped solid-state laser, including optics producing a second or higher harmonic output with greater than 60 watts average output power. The delivered laser radiation has a wavelength for example in a range of about 200 nm to about 650 nm, and has an average irradiance in the treatment area greater than about 10 kilowatts/cm², in a spot size of at least 0.05 mm².

Description

RELATED APPLICATION INFORMATION [0001] This application is a divisional application of U.S. patent application Ser. No. 10 / 371,080 filed 21 Feb. 2003. [0002] Application Ser. No. 10 / 371,080 claims the benefit of U.S. Provisional Application No. 60 / 358,356, entitled METHOD FOR TREATMENT OF GYNECOLOGICAL CONDITIONS USING A HIGH POWER LASER IN CONJUCTION WITH A HYSTEROSCOPE, filed 22 Feb. 2002. [0003] The present application is related to, and incorporates by reference as if fully set forth herein, U.S. patent application Ser. No. 10 / 278,723, entitled METHOD AND SYSTEM FOR PHOTOSELECTIVE VAPORIZATION OF THE PROSTATE, AND OTHER TISSUE, filed 23 Oct. 2002; U.S. patent application Ser. No. 09 / 737,721, entitled METHODS FOR LASER TREATMENT OF SOFT TISSUE, filed 15 Dec. 2000 (now U.S. Pat. No. 6,554,824); and U.S. patent application Ser. No. 10 / 279,087, entitled METHOD AND SYSTEM FOR TREATMENT OF BENIGN PROSTATIC HYPERTROPHY (BPH), invented by Murray, et al.; filed: 23 Oct. 2002.BACKGROUND O...

AI Technical Summary

Benefits of technology

[0028] Accordingly, in one embodiment, the second harmonic output of the neodymium dope solid-state laser is applied using an optical fiber with a flat tip for emitting radiation from the end, or with a side-firing tip. When using a side-firing tip, which causes a diverging beam to be directed out of the optical fiber, the time is placed close to the tissue, within about 1 mm from the side of the side-firing tip to contacting the side of the tip. Close placement increases the irradiance delivered to the treatment area so that higher irradiance is available with solid-state lasers generating a 60 to 80 watts average output power.

[0029] According to the present invention, the efficiency of the vaporization and the reduction of injury to residual tissue are sufficient that the procedure may be carried out while applying less anesthesia during the delivery of laser energy, and throughout the procedure, than during other procedures. Anesthesia options for a procedure according to the present invention include, but are not limited to, paracervical block, and general or regional anesthesia techniques.

[0030] Furthermore, embodiments of the invention include the delivery of the laser energy using a Q-switched, solid-state laser which produces micro-pulses in combination with applying pump power to the laser medium in a sequence a pulses so that output radiation is produced in macro-pulses having a peak power of greater than 200 watts, and more preferably about 240 watts or greater. The peak irradiance in the treatment area during the pulses is thereby substantially increased, and preferably greater than 50 kilowatts / cm2, and as much as 90 kilowatts / cm2 in some embodiments of the invention.

Problems solved by technology

Although 1064 nm light is hemostatic at high power levels, its low absorption in blood and uterine tissue leads to inefficient ablation and a large residual layer of thermally denatured tissue several millimeters thick.

The difficulty of achieving higher average output power densities is that when high input powers are supplied to the laser element from an excitation source such as an arclamp a large amount of heat is generated in the lasing element.

This heat induces various deleterious effects in the lasing element.

In particular the temperature difference between the coolant and the hot lasing element generates a thermally induced graded index lens that decreases the beam quality of the laser and causes the laser to operate with more transverse optical modes than it would otherwise.

The larger number of modes makes M2 larger and makes it difficult to focus the light into small, low numerical aperture fibers and reduces the ability to project high power density light onto tissue.

As a result, the vaporization efficiency of CW arclamp pumped 532 nm lasers is significantly reduced.

Surgical procedures within the uterus have unique risks.

Any surgery in the uterus must avoid weakening of the wall of the uterus, which could lead to complications during pregnancy.

Also, the physiological diversity of the uterus increases the difficulty of intrauterine operations.

In case of a myoma in the cornu, the uterine wall is further thinned by the myoma, which increases the risk of intraoperative perforation of the uterine wall.

Even if perforation does not occur, the presence of a thin uterine wall could predispose the patient to bowel injury.

As stated by Indman, J. Reproduct. Med. 1991, lack of precise knowledge of the minimum thickness of the uterine wall may be the limiting factor in determining the safety of use of the 1064 nm Nd:YAG laser for endometrial ablation.

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