Surgery – Instruments – Light application
Reexamination Certificate
2000-12-06
2003-03-18
Gibson, Roy D. (Department: 3739)
Surgery
Instruments
Light application
C606S011000, C606S018000
Reexamination Certificate
active
06533776
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for tissue treatment, such as for cosmetic tissue treatment, and more particularly to a handpiece for a tissue treatment apparatus comprising a light source.
BACKGROUND OF THE INVENTION
It is known to utilise laser light for tissue treatment.
During tissue treatment, a laser ablates a thin epidermal layer of the derma of a patient. During healing, a new epidermal layer is formed on the ablated surface having the look of the derma of a young person, i.e. the new epidermal layer is formed without previously existing scars, wrinkles, etc.
Lasers that operate at a wavelength that is absorbed in water are used for tissue treatment. When the laser power density (W/mm2) at illuminated cells is sufficient, cellular water is superheated causing small explosions that disrupt heated cells.
During removal of an epidermal layer, it is essential not to damage underlying or surrounding tissue. Residual heat may cause non-ablated cells to char and become necrotic, whereby new scars may be formed and thus, it is desirable to apply laser power for a short time, to minimize transmission of conducted heat to underlying and surrounding tissue.
It is therefore desired to accurately control the amount of light energy transferred to derma to be ablated. The amount of energy must be sufficient for the dermal cells to vaporize and, simultaneously, the amount of residual energy heating non-ablated cells must be so low that non-ablated cells will not be damaged.
Apparatuses for tissue treatment are known, comprising a CO2 laser emitting a laser beam and a laser articulating arm with mirrors for reflection of the laser beam, so that the laser beam is transmitted inside the articulating arm. Further, the arm has a number of joints, so that the arm can be moved around by an operator. A handpiece to be held by the operator is connected to the arm. The laser beam is moved or scanned across a target surface by movable mirrors connected to motors and mounted in the arm. The scan pattern of the laser beam is an archimedes spiral. The laser spot formed by the laser beam on the target surface moves along the spiral at a constant angular speed.
It is a disadvantage of the known apparatus that the energy density delivered to the target surface is non-uniform across the scanned surface area of the spiral, as more energy is delivered at the centre of the spiral than at the circumferential of the spiral.
It is another disadvantage of the known apparatus that the circular outline of the scan pattern leads to non-uniform scanning of an area that is larger than the area of the scan spiral as either 1) areas that have not been scanned will remain on the surface, when abutting spirals or 2) ablated areas will be scanned more than once, due to overlap of spirals.
It is yet another disadvantage of the known apparatus that evaporated derma is exhausted through the internal of the laser articulation arm, whereby optics and other members in the arm get dirty.
It is still another disadvantage of the known apparatus that it is very laborious to disassemble members, that may have been in contact with a patient, from the handpiece, e.g., for autoclaving.
It is still another disadvantage of the known apparatus that movement of the handpiece is restrained by the laser articulation arm, as the construction of tubes interconnected by joints is not fully flexible.
In addition, these apparatus typically have large mass and a large inertia (typically also due to counter-balancing masses) which makes the operation and movement of the arm difficult and heavy.
Under the name Uni-laser 450P, Asah Medico A/S, Denmark, markets an apparatus for cosmetic tissue treatment, comprising a CO2 laser and an optical fiber coupled to the laser at one end and to a handpiece at the other end.
It is a disadvantage of this known apparatus that the laser beam is manually scanned across the target surface whereby the quality of the treatment is determined and limited by the skill of the operator.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus for tissue treatment that is adapted to automatically and accurately ablate dermal cells to a desired depth causing only a minimum of damage to cells that are not removed.
It is another object of the present invention to provide an apparatus for tissue treatment that is adapted to ablate dermal cells uniformly and from a large area of a patient.
It is a further object of the present invention to provide an apparatus for tissue treatment, having a handpiece that can be moved around, i.e. traversed and rotated, freely by an operator, i.e. without exerting forces acting against the movement.
According to a first aspect of the invention, the above-mentioned and other objects are fulfilled by a handpiece for tissue treatment, comprising an input connector for connection of a first beam-outlet end of a first optical fiber to the handpiece and for alignment of the first optical fiber with an axis of the handpiece so that a first light beam emitted from the first beam-outlet end is transmitted substantially along the axis. The handpiece further comprises movable first deflecting means for deflection of the first light beam emitted from the first beam-outlet end of the first optical fiber into a second light beam, and an output for emission of the second light beam towards a target surface.
According to a second aspect of the invention, an apparatus for tissue treatment is provided, comprising a handpiece as described above. The apparatus further comprises a light source for emission of a light beam and being connected to the handpiece with an optical fiber for transmission of the light beam to the handpiece.
When the handpiece is kept in a fixed position in relation to a target surface that is illuminated by the second light beam changing of the position of the deflecting means causes the second light beam to traverse or scan the target surface along a curve. An area may be traversed or scanned by the second light beam, e.g. by letting the second light beam traverse or scan a meander like curve substantially covering the area or, by traversing or scanning the area line by line. In the present context, the type, number and shape of curves traversed by the second light beam in order to traverse a specific area is denoted the traversing pattern or the scan pattern. The area that is scanned or traversed by the second light beam is denoted the scan area, the treatment area or the traversed area.
Cellular water absorbs light energy, and applying light energy to the cells is therefore an efficient way of ablating tissue. Thus, it is preferred to use light sources, such as lasers, generating light at wavelengths with a high absorption in water, preferably wavelengths larger than 190 nm, such as wavelengths in the range from 190 nm to 1900 nm, preferably from 700 nm to 900 nm, and even more preferred approximately 810 nm, or, preferably wavelengths larger than 1900 nm, such as wavelengths in the range from 1900 nm to 3000 nm, preferably from 1900 nm to 2200 nm, preferably from 1900 nm to 2100 nm, and even more preferred approximately 2100 nm, or, from 2800 nm to 3000 nm, and even more preferred approximately 2930 nm, or wavelengths equal to or greater than 4500 nm, such as wavelengths in the range from 4500 nm to 11000 nm, preferably from 4500 nm to 5500 nm, alternatively from 10000 nm to 11000 nm, such as around 10600 nm.
The apparatus according to the invention may not only be used for ablating a thin epidermal layer of the derma of a patient. Also marks on the tissue such as marks from chloasma, liver spots, red spots, tattoos, blood vessels just below the surface, etc., as well as warts, wounds, hair follicles, etc. may be ablated or treated, and hereafter the terms tissue and resurfacing will include these marks and treatments thereof.
It is preferred, that the light source utilized in the present invention is a laser, but also other light sources, such as light emitting diodes and halogen bulbs, may be utilized.
The laser
Asah Bjarne
Balle-Petersen Olav
Dolleris Casper
Asah Medico A/S
Birch & Stewart Kolasch & Birch, LLP
Gibson Roy D.
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