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For over 30 years, surgical
lasers have been used in the field of human medicine. Lasers have also been available to veterinarians for many
years, but it is only in the past four years that the use of surgical
lasers in veterinary medicine has gained widespread acceptance. These commercially available carbon dioxide lasers are now
being utilized by general practitioners to perform many elective
procedures in cats, such as removal of skin masses, neutering, spaying,
and declawing.
What are the advantages of laser
surgery vs. traditional surgery? Laser
surgery causes less post-operative pain, less bleeding, and less swelling.
The disadvantages? The cost: at the moment, laser surgical units are quite
expensive. Veterinarians must
learn basic laser physics and safety, and learn to manipulate the laser
efficiently and effectively. Fortunately,
because the laser can be used daily in general practice, the learning
curve is short. It doesn’t
take long to develop the skill required to hold and guide the laser, and
once mastered, the potential benefits of laser surgery are remarkable.
Most lasers used in small animal
surgery utilize carbon dioxide. Electrical
energy stimulates carbon dioxide which causes it to emit a laser beam of
light. Soft tissue, when hit
with this laser beam, absorbs the energy of the beam.
The energy is rapidly converted into heat.
The heat boils the water in the cell.
The steam produced causes the cell to break apart.
This results in an incision that is cleaner, as the laser
coagulates and seals small blood vessels that are less than half the
diameter of the laser beam, providing moderate control of bleeding.
Lymphatic vessels are sealed as well, resulting in less swelling at
the surgical site. Small
nerve endings are also sealed, resulting in less postoperative pain.
Use of the laser requires
training, both in surgical technique as well as in safety precautions so
that the patient, the staff, and the surgeon are protected from injury.
The Occupational Safety and Health Administration (OSHA) has
published requirements on laser safety protocols, requiring a veterinary
staff member to be a designated laser safety officer (LSO), and the
American National Standards Institute has published guidelines regarding
laser safety (ANSI Z1363, Safe Use of Lasers in Health Care Facilities)
which should be required reading by veterinarians using surgical lasers.
A smoke evacuation system is necessary to remove the plume of smoke
that results when the laser beam contacts the tissue.
The laser plume, which is mostly water vapor, has also been shown
to contain inorganic compounds such as carbon monoxide and other sulfur
compounds, organic compounds such as cyanide and formaldehyde, and
microorganisms such as bacteria, fungi, and viruses.
Special masks (with very fine pores) must be worn by all personnel
in the vicinity, to avoid inhaling any of these substances that may be
missed by the smoke evacuator. In
addition to masks, everyone near the surgery room must wear special
goggles or eyewear, as direct or indirect laser light can cause permanent
eye damage. The animal
undergoing the procedure must also have its eyes protected from stray
laser beams. Potential
reflection from surgical instruments must be avoided, and one must take
care not to use flammable anesthetic gases or accidentally make a laser
incision into the endotracheal tube.
The most common laser procedures
performed on cats include neutering, spaying, de-clawing, and skin mass
removal. Using the laser for
feline castration results in less patient discomfort and reduced bleeding.
When the laser is used to transect the testicular artery, vein, and
vas deferens, the vessels and nerves are sealed immediately, resulting in
no bleeding, and no pain. Spaying with the laser has similar advantages – diminished
bleeding, swelling, and pain – however, as with any surgery in which the
abdomen is opened, internal organs such as the liver, spleen, bladder,
intestines, etc. must not be hit with the laser, or inadvertent
vaporization may result. Skin
mass removal is easily accomplished with the laser.
Removal of highly vascularized skin tumors in the traditional
fashion often requires a considerable amount of time, most of which is
spent controlling bleeding from vessels in the mass.
Lasers, by sealing blood vessels as they cut the skin, provide
unprecedented speed when removing skin masses.
Small masses (less than 5 millimeters in diameter), such as warts,
do not need to be removed and sutured using the laser.
Using a 0.8 mm laser tip and a continuous stream of laser energy,
small masses can be ablated (burned away).
The remaining defect, rather than be sutured, can be mildly charred
using a less intense beam, with the charred tissue serving as a
“bandage”. An antibiotic
ointment applied to the site keeps the tissue moist, and results in rapid
healing. Lasers are also useful in managing contaminated wounds, as
bacteria, fungi, and viruses are vaporized by the carbon dioxide laser,
effectively disinfecting the tissue.
Feline onychectomy (declawing) is
a procedure that is still viewed with controversy by cat owners, breeders,
and veterinarians. The carbon
dioxide laser, when used in declawing, is said to reduce post-op pain,
bleeding, and swelling. Cats,
as a result, return to their normal activity more rapidly.
The technique requires training and practice.
Excessive, inadvertent lasing of tissues can cause undue heating of
tissues, resulting in pain and swelling post-operatively.
Unlike conventional declawing, bandaging the feet is not required
when using the laser for the procedure.
A recent report in the September 1st, 2002 issue of the
Journal of the AVMA entitled “Use of Carbon Dioxide Laser for
Onychectomy in Cats” compared postoperative signs of discomfort and
complications in cats de-clawed with the laser vs. those de-clawed
conventionally (with a scalpel). The
study concluded that neither technique resulted in high discomfort or
complications, although the laser treated group had lower scores for signs
of discomfort and complication on the day after surgery.
On the seventh day after surgery, there were no significant
differences between laser-de-clawed cats and conventionally de-clawed
cats.
As
laser surgery gains wider acceptance, the price of the surgical unit is
certain to drop, becoming affordable for many general practitioners.
Recognizing that laser surgery would rapidly grown in popularity,
The Veterinary Surgical Laser Society (VSLS) was formed in 1999 to help
guide veterinarians seeking to develop knowledge and expertise in this
field. The VSLS sponsors
continuing education courses in the use of lasers. Refinements in the equipment are bound to make it
easier to use, improving the surgical outcome for many feline patients.
Updated 2/9/06
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