I am an owner of a busy small animal veterinary hospital in Nagoya, Japan. One day I encountered a book on CO2 laser surgery and became fascinated with the technology that brings less bleeding, less swelling, less pain and less risk of infection. It goes without saying that less stress during and after surgical treatment is the best for humans and for animals.
I decided to learn more about small animal soft tissue laser surgery in the USA, and did so for two years at various private practices and at Louisiana State University. At the same time I studied to become a diplomate of the American Board of Laser Surgery (ABLS). Learning the art of laser surgery from the best veterinary laser surgeons in the U.S. and through ABLS allowed me to select the best surgical laser for my hospital back home.
Types of Medical Lasers
It is important to select the type of surgical laser by its wavelength and how it interacts with the tissue. Medical lasers can be assigned to one of three categories:
WYSIWYG stands for “What you see is what you get.” This type is suitable for precise surgery with minimum thermal damage to adjacent tissue, because for those wavelengths the absorption coefficient is dominant over scattering coefficient in soft tissue. Examples are CO2 at 10,600 nm and Er:YAG at 2,940 nm, but the CO2 laser offers also a superior hemostasis over the Er:YAG laser.
WYDSCHY stands for “What you don’t see can hurt you.” For this type, the scattering of laser light inside the soft tissue is dominant over the absorption. As a result, the laser light spreads deep and wide inside the soft tissue, which can cause extensive and far-spread thermal necrosis at high power densities relevant to surgical applications.
WYDSCHY examples include Nd:YAG laser at 1,064 nm and laser diodes in the wavelength range of 800-1,000 nm intended for surgical use (i.e. not therapy). The safest way to use WYDSCHY laser surgically is not to use the laser light directly on the tissue, but only as a heat source to heat up the surgical tip (of glass fiber, either bare glass or sometimes with metal tip over the glass) in a “contact” mode where the heat (and not the laser light) interacts with the soft tissue.
SYCUTE stands for “Sometimes You Can Use Them Effectively.” This type is useful for color-selective thermolytic destruction of pigmented tissue. Examples include Alexandrite laser at 755 nm and laser diodes in the wavelength range of 800-1,000 nm in highly successful human cosmetic applications where the laser light is used for hair removal (diodes) and skin pigmentation removal (Alexandrite).
Another SYCUTE example is laser therapy using 800-1,000 nm laser diodes at low power densities (i.e. not for surgery). These wavelengths exhibit low water absorption and have significant scattering in soft tissue allowing for deep and wide penetration of laser light. Another great application for laser diode is ICG-augmented diode laser treatment of leg veins–it only works with ICG pigment and is a perfect illustration of the SYCUTE concept.
Why CO2 Laser?
A review of available surgical laser technologies reveals that the CO2 laser at 10,600 nm wavelength is the most suitable for the soft tissue surgery. It is one of the simplest WYSIWYG lasers and it is not surprising that it is the most common surgical laser in human and veterinary medicine.
Ever since the invention of the CO2 wavelength compatible flexible fiber (to be exact, this is a hollow reflective light guides made of metal with the interior surface highly polished and anti-reflective coated), the American made flexible fiber surgical CO2 lasers became the lasers of choice for small office surgery around the globe. They bring simplicity and convenience to laser surgery unobtainable with older articulated arm lasers.
My choice was for flexible fiber CO2 laser from Aesculight with its pioneering tipless laser handpiece that is used like a drawing pen during surgery. It features an on-board library of laser surgery cases, and is pre-programmed with useful pulsed and Super-Pulsed modes for ease of operation. It is rugged, durable and versatile, and has proven so far to be the right choice for our hospital.
CO2 Laser Surgery Case Studies
I use my CO2 laser for all surgeries at the hospital. There are some surgery cases that are hard to do without the CO2 laser. Skin incisions illustrated in Figure 1 are easy to perform with the tipless laser handpiece under the correct power and proper focal spot size settings of 0.25 mm, resulting in clean bloodless margins that heal easy and without complications.
The diode laser is not appropriate in this case as the skin gets damaged excessively due to slow thermal conduction of heat from the tip (glass or metal) to and through the soft tissue.
Another great illustration of surgical CO2 laser in action is femoral head osteotomy with much reduced intra-operative bleeding (Figure 2) that greatly simplifies the surgery.
For oral tumor (Figures 3A and 3B) palliative resection, I use the CO2 laser to remove the tumor and to assist the maxillectomy while maintaining excellent hemostasis (Figures 3C through 3E). For the CO2 laser assisted maxillectomy, I use the cold saline flush to protect and facilitate cooling of the surrounding bone tissue. Figure 3D shows a bubble formed by laser beam striking a saline solution. Figure 3E illustrates dry, bloodless surgical site immediately after maxillectomy. A much improved patient is presented in immediate post-op image in Figure 3F.
Enucleation is much simplified if performed with a CO2 laser. All stages of the procedure are literally blood-free: conjunctiva incision (Figure 4A), eye muscle resection (Figure 4B), removal of the eyeball (Figures 4C and 4D) and eyelid resection (Figure 4E). A great outcome is presented in the immediate post-op image in Figure 4F.
My experience with CO2 laser for surgery at our hospital is in sync with how laser surgery is practiced in North America. It is a new and pioneering concept, however, in Japan, where until now laser diodes were promoted for soft tissue surgery. Hopefully more laser veterinarians from Japan can get trained at the American Board of Laser Surgery in the advantages of CO2 laser wavelength for soft tissue surgery—and for the benefit of our patients.
Dr. Masahiro Seki is the owner of a small animal clinic Animal Laser Center in Nagoya, Japan. He is the first board certified veterinary laser surgeon in Japan. He uses both the CO2 and diode laser wavelengths in his practice. Dr. Seki is a diplomate of American Board of Laser Surgery, and a director at the Japanese Laser Veterinary Science Society.
This Education Series article was underwritten by Aesculight LLC of Woodinville, Wash., manufacturer of the only American-made CO2 laser.