MXPA99006462A - Stimulation of biological tissue through energiaopt - Google Patents

Abstract

The biological tissue of a living being is irradiated with optical energy at a wavelength and at a level of energy dissipation to cause the amount of optical energy absorbed and converted to heat in the tissue to be within a scale bound by a minimum absorption range. sufficient to raise the average temperature of the irradiated tissue to a level above the basic body temperature, but which is less than the absorption range at which the tissue is converted into a collagen substance. According to this method, a therapeutic, heating effect is produced within the irradiated tissue, but without causing tissue damage due to thermal overheating. The method of using a reactive low-level system from 100 milliwatts per square centimeter to 1000 milliwatts per square centimeter, either in a pulsed or continuous mode with energy produced by a beam, is Nd: YAG at a wavelength Fundamental of 1064 manometers, which has been found to reduce pain in soft tissues, reduces inflammation and improves tissue healing by stimulating nicotcirculation without subjecting living tissue to harmful thermal effects. The energy density of the irradiated tissue is limited to the scale from about 0.1 joule per square centimeter to about 15 joules per square centimeter. An alternative method produces the optical power by means of a beam l be Nd: YLF at a wavelength of 1,055 nanometers. Other beams could be used that would produce the optical power on a preferred scale from about 950 to about 1200 gauges in the range of energy desired.

Description

STIMULATION OF BIOLOGICAL TISSUE THROUGH OPTIC ENERGY FIELD OF THE INVENTION The present invention relates generally to the treatment of living biological tissue by optical irradiation and especially to a method for stimulating soft living tissue by laser irradiation.

ANTECEDENTS OF ART Several non-surgical means have been used in the therapeutic treatment of living tissue. These techniques have included the application of ultrasonic energy, electrical stimulation, high frequency stimulation by diathermy, X-rays and microwave irradiation. Techniques such as electrical stimulation, diathermy, X-rays and microwave radiation have shown some therapeutic benefits for soft tissues. However, its use has been somewhat limited due to tissue damage caused by excessive thermal effects. Consequently, the energy levels associated with therapeutic treatments with diathermy, X-rays, microwave and electric stimulation have been limited to such low levels that little or no benefit has been obtained. In addition, the dose or exposure to radiation by microwaves and X-rays must be carefully controlled to avoid radiation related to greeting problems. The ultrasonic energy is not preferably absorbed and affects all the surrounding tissue.

The optical energy generated by the laser has been applied for various medical and surgical purposes due to the monochromatic and coherent nature of the laser light which can be selectively absorbed by the living tissue depending on certain characteristics of the wavelength of light and irradiated tissue properties, including reflectivity, absorption coefficient, scattering coefficient, thermal conductivity and thermal diffusion constant. The reflectivity, absorption coefficient and scattering depend on the wavelength of the optical radiation. It is known that the absorption coefficient depends on factors such as interband transition, free electron absorption, absorption by casting (sound absorption), and absorption of impurities, which depend on the wavelength of the optical radiation.

In living tissue, water is an important component which has an absorption path according to the vibration of water molecules in the infrared range. In the visible range, there is absorption due to the presence of hemoglobin. In addition, the coefficient of spreading in living tissue is a dominant factor.

Thus, for a given type of tissue, the laser light can propagate through the tissue, substantially not weakened, or it can be almost completely absorbed. The extent to which the tissue is heated and ultimately destroyed depends on the extent to which it absorbs the optical energy. It is usually preferred that the laser light is essentially transmissible in tissues which it is desired to protect, and absorbed by the tissues to which it will be affected. For example, when applying laser radiation in a tissue field which is wetted with blood or water, it is desired that the optical energy is not absorbed by water or blood, thereby allowing the laser energy to be directed specifically to the tissue under treatment. Another advantage of laser treatment is that the optical energy can be brought to tissue treatment at a precise, well-defined location and at predetermined and limited energy levels.

It is known that ruby and argon lasers emit optical energy in the visible portion of the electromagnetic spectrum and that they have been used successfully in the field of ophthalmology to reinstate retinas to the fundamental choroidal and to treat glaucoma by perforating anterior parts of the eye to release interocular pressure. The energy of the ruby laser has a wavelength of 694 nanometers and is in the red portion of the visible spectrum. The argon laser emits energy at 488 and 515 nanometers and thus appears in the blue-green potion of the visible spectrum. The rays of the ruby and argon laser are minimally absorbed by the water, but very strongly absorbed by the chromogenic hemoglobin in the blood. In such a way that the laser energy of ruby and argon is poorly absorbed by non-pigmented tissue such as the cornea, lens and vitreous humor of the eye, but is preferably absorbed by the pigmented retina where it can then exert a thermal effect. Another type of laser that has been adapted for surgical use is the gas laser of carbon dioxide (CO2) which emits an optical ray which is absorbed intensely by water. The wavelength of the CO2 laser is 10.6 micrometers and is therefore invisible, far from the region of the electromagnetic spectrum, and is absorbed independently of the color of the tissue by all soft tissues having a water content. In this way the CO2 laser is an excellent surgical scalpel and vaporizer. As it is completely absorbed, its depth of penetration is low and can be precisely controlled with respect to the surface of the tissue being treated. The CO2 laser is so well adapted for use in various surgical procedures in which it is necessary to vaporize or coagulate neutral tissue with minimal thermal damage to nearby tissues. Another laser of great use is the neodymium laser doped with yttrium-aluminum-coupled (Nd: YAG). The LASER Nd: YAG has an important mode of operation at its secondary wavelength of 1,320 nanometers in the near infrared region of the electromagnetic spectrum. The optical emission of Nd: YAG is absorbed to a larger extent by blood than by water, making it useful for the coagulation of large bleeding blood vessels. The Nd: YAG laser at 1,320 nanometers has been transmitted through endoscopes to treat a variety of gastrointestinal bleeding lesions, such as varices in the esophagus, peptic ulcers and arteriovenous anomalies. Said applications of laser energy are thus well adapted where high energy thermal effects are needed, such as tissue vaporization, tissue cauterization, coagulation and as a surgical scalpel. The following US patents show apparatus and methods for therapeutic treatment of living tissue by laser irradiation: 3,456,651 3,720,213 4,141,362 4,144,888 4,367,729 4,561,440 4,573,465 4,589,404 4,601,288 4,604,992 4,672,969 4,692,924 4,705,036 4,931,053 4,966,144 Three patents; Dew, 4,672,969; L'Esperance, Jr. 4,931,053 dated June 5, 1990; and Rochkind, et al 4,966,144 dated October 30, 1990, best describe prior art. This prior art teaches the use of laser energy in certain specific applications. Dew discusses the use of a laser, specifically a type of Nd: YAG laser operated with a secondary wavelength of 1,320 nanometers. Dew shows that Nd: YAG lasers typically operate at 1,060 nanometers. The purpose of the Dew patent is to use a laser for effects of closeness of the wound and reconstruction of biological tissue. The laser energy is converted into heat which in the end divides the tissue into collagens which act as "biological glue". L'Esperance teaches the use of two laser beams used in visible red or under infrared and lasers with very low power to irradiate the tissue. L'Esperance teaches us the use of either helium-neon or krypton lasers. The wavelength used by L'Esperance is 610-660 nanometers with an output of .15 milliwatts. The Rochkind patent dated October 30, 1990, uses either coherent or non-coherent life, but describes a helium-neon laser operating at 632 nanometers with an intensity of 16 milliwatts per square centimeter or an argon-type laser generating disturbance to 465 or 520 nanometers with a light intensity of approximately 40 milliwatts per square centimeter. In addition, Rochkind describes a two-step process in achieving the methods sought in the invention; a first treatment while the tissue is open and exposed during surgery and a second treatment after closure.

INDUSTRIAL APPLICATION The application of conventional lasers for the purpose of stimulation of soft tissue that causes a reduction of pain and inflammation, in stimulation of microcirculation to reduce the healing time has been attempted at very low power levels, normally below 100 milliwatts per square centimeter . Although some therapeutic benefits have been achieved, the treatment time has been unacceptably long. Similarly, the purpose of the present invention is to provide a method for the safe and effective application of reactive laser energy to living tissue for therapeutic purposes, for example, to reduce pain, reduce inflammation at high power levels, and to help tissue healing by stimulating the microcirculation, without exposing the tissue to thermal damage. This method reduces the treatment time beyond what is known by the art.

DISCLOSURE OF THE INVENTION It has been found that the method for using a low level reactive laser system of 100 milliwatts per square centimeter at 1000 milliwatts per square centimeter or preferably at 800 milliwatts per square centimeter either in a pulsed or continuous mode, such as with optical energy produced by a Nd: YAG laser at a fundamental wavelength of 1,064 nanometers, it reduces pain in soft tissue, reduces inflammation and aids tissue healing by stimulating microcirculation without exposing living tissue to damage thermal. In an alternate method, the optical energy is produced by a neodymium doped lithium-fluoride (Nd: YLF) laser at a wavelength of 1,055 nanometers or by another laser in a range of 950 to 1,200 nanometers and preferably at a range of wavelength from 1,000 to 1,150 nanometers. The living tissue is irradiated with optical energy at a wavelength and at a level of power dissipation in the tissue to cause the amount of optical energy absorbed and converted into heat to be in a range circumscribed by a minimum absorption rate sufficient to raise the average temperature of the irradiated tissue at a level above the basal body temperature, but that is less than the absorption rate at which the tissue is converted to a collagen substance. The wavelength, point or size of the beam, power and time of eure are carefully controlled to produce an evident heating effect in the irradiated tissue, but which is limited to avoiding damage to the tissue by thermal effects. In another embodiment of the present invention designed to take advantage of lasers with wider beam, the power range would be approximately 100 to 1000 milliwatts per square centimeter of the treated area.

None of the prior arts mentioned teaches the present invention. As stated in the specification, the Nd: YAG laser operates at its primary wavelength of 1,064 nanometers with a power of 100 milliwatts per square centimeter at 1000 milliwatts per square centimeter or an Nd: YLF laser operating at a wavelength of 1,055 nanometers with the same power. Neither L'Esperance nor Rochkind teaches the use of the Nd: YAG laser in this particular mode. Both L'Esperance and Rochkind detail the preferred method of operation as a wavelength approximately half that of the present invention. In fact, L'Esperance uses two rays instead of one. None of the prior arts discloses the use of an Nd: YAG laser as its primary wavelength of 1,064 nanometers. The following table compares the arts of Dew, L'Esperance and Rochkind with the present invention: While L'Esperance could teach Rochkind, none of the previous arts does not even allude to the fact that the Nd: YAG laser could be used in this modality with such power and desired results.

THE BEST WAY TO CARRY OUT THE INVENTION According to the preferred method, the laser energy is produced by a Nd: YAG laser at a fundamental wavelength of 1,064 nanometers at a power output level of about 100 milliwatts per square centimeter to plus or minus 1000 milliwatts per square centimeter or approximately 800 milliwatts per square centimeter. The optical energy of the laser is applied to body re-ions which require a decrease in muscle spasm, increased circulation, less pain or support in tissue healing. The surface area is demarcated and the surface of the tissue is irradiated with the laser beam for the time and intensity necessary to produce the desired therapeutic effect, with the energy density of the irradiated tissue limited to a range of approximately .1joule / cm2 at about 15 joules / cm2 or a preferred range of about 1 joule / cm2 to about 15 joules / cm2. The time and intensity of treatment is determined by the nature of the tissue to be treated, the depth of penetration desired, the severity of the injury and the condition of the patient. In a preferred method, the amount of time is in the range of about 1 second to plus or minus 150 seconds. The laser is operated below the tissue photoablation threshold (PAT). In a particular method, the treated tissue is irradiated with coherent optical energy radiation to a plurality of small areas in treatment in a grid for the time and intensity necessary to give a therapeutic effect. Each small treated area is in the range of approximately 0.5 per square centimeter to plus or minus 50 square centimeters or in a particular range of approximately 2 square centimeters. In a particular method, the treatment duration per area is in the range of about 1 second to plus or minus 150 seconds. It has been proven that the therapeutic method using a low level reactive laser system reduces pain, inflammation and helps healing damaged tissue by stimulation of microcirculation, all of which are successfully achieved without causing thermal damage to the tissue. An Nd: YAG resonant laser was used as the source laser. Its main wavelength was 1,064 nanometers, and it had an adjustable beam power density of 100 milliwatts per square centimeter at 800 milliwatts per square centimeter. The laser could be operated in a pulsed or continuous mode, and its output was controlled by an exposure timer in the range of 0.1 minutes to 9.9 minutes. The time pulse was adjustable from 0.1 seconds to 9. seconds with 0.1 second intervals and was used in a preferred range of approximately 1.0 seconds to plus or minus 9.9 seconds. The out-of-time pulse was also adjustable from 0.1 seconds to 9.9 seconds with 0.1 second intervals. The Nd: YAG laser beam operates in the near infrared part of the electromagnetic spectrum at 1, 064 nanometers and in this way is invisible. The method to bring the beam to the target in sight is through a flexible quartz fiber and a focusing instrument. The Nd: YAG laser beam exits the output copy of the laser head and is directed by a pair of alignment wedges before passing through a circular variable attenuator of neutral density. The light that passes through the attenuator is focused through a pair of focal glasses of 90 mm. long to the proximal end of a fiber optic cable. The main beam attenuator is a lock placed outside the laser head between the laser output copy and the beam directional mirror. It includes four components: a 90-degree reflector prism, a shutter arm, a shutter mounting brake and a solenoid in operation. The prism is assembled to the obturator arm in such a way that, in the normal closed position, the prism intercepts the laser beam and reflects it downwards in a ray deposit on the laser cover. The solenoid is energized when an exit channel has been selected and a foot pedal is pressed, which causes the obturator arm to rise and allow the beam to pass. When the solenoid arm is de-energized, the shutter drops to the closed position. The optical energy is produced by a coherent light source, preferably a laser having a wavelength of 1,064 nanometers in the near infrared region of the electromagnetic spectrum. The laser is enabled with a fiber optic guide and a copy to direct the ray of optical energy to the tissue surface. The energy of the optical radiation is controlled and applied to produce a minimum rate of absorption in the irradiated tissue which will raise the average temperature of the irradiated tissue to a level above the basal body temperature, but not exceed the maximum rate of absorption, which is large enough to convert the irradiated tissue to collagen substance. It has been determined by various tests that the above condition is satisfied by a Nd: YAG laser operated at a primary wavelength of 1,064 nanometers at a power output level of 100 to 800 milliwatts per square centimeter, with the laser beam focused for produce an energy density of the projected laser beam in the range of approximately 1.0 joule / cm2 to approximately 15 joules / cm2 in the treatment area.

Certain psychological mechanisms have been observed in the tissue and at the cellular level, when the aforementioned process is used. In the evaluation of the microcirculatory system, for example, the walls of the blood vessels have been shown to have photosensitivity. When the walls of the blood vessels are exposed to laser radiation as stated above, the tone is inhibited in smooth myocytes, thereby increasing the blood flow in the capillaries. Other effects which have been observed are: capillary neovascularization periphery, reduced platelet whole blood, reduction of O2 to form triplet only allowing tissue larger oxygenation, reducing concentration of buffer substances in the blood, stabilization the rates of erythrocyte deformation, reduction of oxygenation products of perioxidized lipids in the blood. Other effects which have been observed are higher antithrombin activity index, enzyme stimulation of the antioxidant system such as dismustase and catalase. An increase in the veins and lymph and the flow of the irradiated region have been observed. The permeability of the tissue in the area is substantially increased. This helps reduce the concentration of edema and bruises in the tissue. At the cellular level, it has also been noted that the mitochondria produce higher amounts of ADP with subsequent increase in ATP. It seems that there is also a greater stimulation of calcium and sodium pumps in the tissue membrane at the cellular level.

At a neuronal level, the following effects have been observed as a result of previous therapeutic treatment. First, there is an increase in the action potential of compressed and intact nerves. The blood supply to the number of neuroaxis increases in the irradiated area. The inhibition of scar tissue is noted when the tissue is treated. There is an immediate increase in the permeability of the nerve membrane. Long-term changes in the permeability of calcium and potassium ions through the nerve have been observed for at least 120 days. Increase RNA production and subsequent DNA production. The singlet O2 is produced which is an important factor in cell regeneration. Pathological degeneration with nerve injury is changed to regeneration. Both astrocytes and oligoderocytes are stimulated, which causes a greater production of peripheral nerve neuroaxis and myelin. The phagocytosis of the blood cells is increased, by this means the infection is substantially reduced. There also seems to be a significant anti-inflammatory phenomenon which decreases the inflammation of tendons, nerves, pockets in the joints, while at the same time producing a strengthened collagen. There is also an effect of the significant increase in tissue granulation in the healing of open wounds under limited circulation conditions. Tissue analgesia has been observed in relation to a complex series of tissue level actions. Locally, there is a reduction in inflammation, causing a reabsorption of the exudates. Enkephalins and endorphins are supplied to modulate pain at both the level of the spinal cord and the brain. The serotonigenic pattern is also supplied. As long as it is not fully understood, it is believed that tissue irradiation causes the return of an energy balance at the cellular level that is the reason for pain reduction. In an alternate method, laser energy is produced by a Nd: YLF laser at a wavelength of 1,055 nanometers. Other lasers could be used or developed to operate in a range of 950 to 1,200 nanometers to a particular range of approximately 1,000 to plus or minus 1,150 nanometers at the same power level.

In another alternate method of the present invention designed to take advantage of lasers with wider beam, the power range would be from about 100 milliwatts per square centimeter to 1000 milliwatts or less per square centimeter of treated area. In such a way a laser with a beam of a diameter of three inches would expose a total area of 45 square centimeters in such a way that the power would be in a range of approximately 4.5 watts to plus or minus 45 watts. In such a methodWhen the treated tissue is irradiated with coherent optical energy radiation in a plurality of small areas treated in a grid for the time and intensity necessary to give a therapeutic effect, each small treated area is in the range of approximately 0.5 square centimeters to about 8 square centimeters.

Although the invention has been described with reference to the particular method, and with reference to specific therapeutic applications, the foregoing description is not intended to be understood in a limiting sense. The modifications of the disclosed presentation as well as alternative applications of the invention will be suggested to persons skilled in the art by the above specification. It is, therefore, contemplated that the appended claims will cover any modification or presentation that fall within the true scope of the invention.

Claims (20)

1. CLAIMS 1. A method for treating a small area of biological tissue of a living subject without exposure of the tissue to damage by thermal effects, said method comprising: the use of a low level reactive laser to generate coherent optical energy radiation below the photoablation threshold of the tissue, with a wavelength in a range of about 1,000 nanometers to about 1,150 nanometers at an output power in the range of about 100 milliwatts per square centimeter to about 800 milliwatts per square centimeter, and focusing said radiation the optical energy coherent to said small area under treatment to reach a rate of absorption and conversion to heat in the irradiated tissue in the range between a minimum rate, sufficient to raise the average temperature of the irradiated tissue to a level above the basal temperature of the body of the living subject, and a maximum rate which is less than the rate at which the irradiated tissue is converted to a collagen substance, wherein the radiation density of the optical energy is in the range of about 1.0 joule / cm2 to about 15 joules / cm2 in the area of irradiated tissue.
2. 2. A method according to claim 1 wherein said wavelength is approximately 1.055 nanometers.
3. 3. A method according to claim 2 wherein said low level reactive laser comprises a Nd: YLF laser.
4. 4. A method according to claim 3 wherein said tissue is irradiated with said radiation of optical energy to a plurality of small areas under treatment for the time and intensity necessary to provide a therapeutic effect.
5. 5. A method according to claim 4 wherein each small treated area is in the range of about 0.5 square centimeters to plus or minus 2 square centimeters.
6. 6. A method according to claim 3 wherein said low level reactive laser is pulsed, with each pulse in time being in the range of about 1 second to plus or minus 9.9 seconds and each pulse out of time being in the range from 0.1 seconds to plus or minus 9.9 seconds.
7. 7. A method according to claim 3 wherein said low level reactive laser is operated continuously.
8. A method according to claim 1 wherein said tissue is irradiated with said radiation of optical energy in a plurality of areas under treatment for the time and intensity necessary to provide a therapeutic effect.
9. 9. A method according to claim 1 wherein each area under treatment has an area in the range of about

   0. 5 square centimeters to plus or minus 2 square centimeters.
10. 10. A method according to claim 1 wherein said low-level reactive laser is pulsed, with each pulse in time being in the range of about 1 second to about 9.9 seconds and each pulse out of time being in the range of 0.1 seconds to 9.9 seconds
11. 11. A method according to claim 1 wherein said low level reactive laser is operated continuously.
12. 12. A method for treating an area of biological tissue of a living subject without exposing the tissue to damage by thermal effects, said method comprising: using a low-level reactive laser for general radiation of optical energy below the photoablation threshold of the tissue having a wavelength in a range of about 950 nanometers to plus or minus 1200 nanometers at a power output in the range of about 100 milliwatts per square centimeter to 1000 milliwatts per square centimeter, and focusing said coherent optical energy radiation at said area treated to reach a rate of absorption and conversion to heat in the irradiated tissue in the range between a minimum rate, sufficient to raise the average temperature of the irradiated tissue to an level higher than the basal body temperature of a living subject, and a maximum rate which is less than the rate at which the irradiated tissue is converted into a collagen substance, wherein the intensity of the optical energy radiation is in the range of about .1 joule / cm2 to plus or minus 15. joules / cm2 in the irradiated tissue area.
13. 13. A method according to claim 12 wherein said tissue is irradiated with said radiation of coherent optical energy in a plurality of area under treatment for the time and intensity necessary to provide a therapeutic effect.
14. A method according to claim 13 wherein each area under treatment has an area in the range of about 0.5 square centimeters to plus or minus 50 square centimeters.
15. 15. A method according to claim 13 wherein said low level reactive laser is pulsed, with each pulse in time being in the range of about 1 second to plus or minus 9.9 seconds and each pulse out of time being in the range from 0.1 seconds to 9.9 seconds.
16. 16. A method according to claim 13 wherein the low level reactive laser is operated continuously.
17. A method according to claim 12 wherein said low level reactive laser is pulsed, with each pulse in time being in the range of about 1 second to plus or minus 9.9 seconds and each pulse out of time being in the range 9.9 seconds.
18. 18. A method according to claim 12 wherein said low level reactive laser is operated continuously.
19. 19. A method according to claim 12 wherein the time that the optical energy is focused to the area under treatment is from about 1 second to plus or minus 150 seconds.
20. 20. A method according to claim 12 wherein each area under treatment has an area in the range of about 0.5 square centimeters to plus or minus 50 square centimeters. RESU M EN The biological tissue of a living being is irradiated with optical energy at a wavelength and at a level of energy dissipation to cause the amount of optical energy absorbed and converted to heat in the tissue to be within a bound scale by a minimum absorption range sufficient to raise the average temperature of the irradiated tissue to a level above the basic body temperature, but which is less than the absorption range at which the tissue is converted into a collagen substance. According to this method, a therapeutic, heating effect occurs within the irradiated tissue, but without causing tissue damage by thermal overheating. The method of using a low-level reactive laser system from 100 milliwatts per square centimeter to 1000 milliwatts per square centimeter, either in a pulsed or continuous mode with energy produced by a Nd: YAG laser beam at a fundamental wavelength of 1,064 nanometers, which has been found to reduce pain in soft tissues, reduce inflammation and improve tissue healing by stimulating microcirculation without subjecting living tissue to damaging thermal effects. The energy density of the irradiated tissue is limited to the scale from about 0.1 joule per square centimeter to about 15 joules per square centimeter. An alternative method produces the optical energy by means of a Nd: YLF laser beam at a wavelength of 1.055 nanometers. Other laser beams could be used that would produce the optical energy on a preferred scale from about 950 to about 1,200 nanometers in the desired energy range.