Laser technology offers wide range of surgical applications

The past decade has seen a steady growth in laser energy used by general veterinary practitioners. Today, veterinary medicine is enjoying a rapid acceptance of various forms of laser energy as a companion and often superior therapeutic modality for surgical case management.

Veterinarians as a group always seek, when possible, to implement new procedures and technologies when a true value to the patient and client are noted. In the case of laser technologies, their proper place in veterinary practice and rapid acceptance has been fueled by a ground swell of commonsensical adaptations to already accepted therapeutics and surgical technique from a small, but growing, number of veterinarians.

Photo 1: Surgical procedure using CO2 laser energy delivered via a hollow wave guide, and handpiece with interchangeable tips.

Creating a surgical trend

Veterinarians who use laser technology in their practices do so because they report consistent results including reduced surgical time, reduced surgical equipment use, consistent tissue interaction and reproducible surgical procedural effects for reducing intra- and post-operative bleeding, controlling swelling, and reducing surgical and therapeutic site pain.

This has spurred laser energy use as a technology with broad application in the minds of many practitioners (Photo 1). Because of the apparent common sense way in which various forms of laser energy apply to a broad range of medical and surgical cases, general practitioners are successfully using laser technology daily without a large number of textbook or journal references to rely on. After gaining a basic understanding of the underlying physical properties associated with laser energy, most veterinarians I have lectured feel that as a tool, laser energy's functionality is already clearly understood as a force for enhancing the level of care to the patient. These conditions range over all areas of soft tissue interaction.

"Anywhere you think you can use laser energy you probably can" is the commonly accepted response from lecturers and practitioners in countless courses I have attended and taught. I truly feel that the use of laser energy in veterinary medicine will become a standard of care much like sterile technique and the use of surgical gloves are now for the veterinary community.

Photo 2: A standard surgery pack used with laser surgery.

Patti Conway, executive director of the Veterinary Surgical Laser Society (VSLS) indicates that nearly 3,000 general and specialty practitioners, who are active members of the VSLS, have already made it the technology standard of care in their practices. In some cases laser technology has replaced the use of "cold steel" and in other areas it has augmented or modified traditionally accepted surgical techniques.

Educational opportunities

Spurred on by quality, reliable, feature-filled, state of the art equipment that has shown the ability to pay for itself easily, many veterinarians are signing up to attend basic and advanced laser science courses to learn firsthand about laser energy and its potential for improving the treatment and surgical capacity of their practice. The use of cold steel will likely never be replaced, but veterinarians are quickly coming to understand the value-added service laser technology can be as a device in their surgical and therapeutic armamentarium (Photo 2). Courses are being offered at national, regional and local meetings. Long time veterinary laser manufacturing leaders such as Lumenis/Accuvet and other more-recent-to-market manufacturers and resellers of veterinary lasers will be committing more than $1 million dollars on educational support at national, state and local veterinary meetings on an annual basis for the foreseeable future. They will likely increase that support level due to expanding demand for course-based knowledge about multiple laser wavelengths and the technology that supports it.

Hands-on wet labs, which provide the veterinary practitioner with experience on a variety of procedures from standard orchiectomies and ovariohysterectomies to advanced techniques for total ear ablations, are in great demand. Each of the national veterinary conferences will support a full day of basic and advanced laser coursework during their respective conventions. The courses, which are limited in class size, continue to be some of the first courses to fill up during advanced registration.

Photo 3: Accuvet 20-watt CO2 laser, Lumenis, Inc, Santa Clara, Calif.

Pioneers in the field of veterinary laser medicine such as Dr. Ken Bartels and Dr. George Peavy are among the luminaries that routinely provide their expert knowledge of the interaction and effect of laser energy on mammalian tissue. They, along with other noted laser pioneers, provide their expertise in a number of areas related to the physics, safety and clinical use of various types of laser wavelengths and equipment types.

Choosing the right wavelength for your practice

The clinical relevance of using laser energy is now becoming universally accepted by most practitioners. Some practitioners still prefer to wait for more complete justification of the technology or are downplaying its reported attributes until more substantial controlled studies are completed. This is an appropriate response, but those veterinarians who have already embraced and implemented the use of laser energy in their practices believe that to wait would be to lose out on technology that is already proven in the human arena of medicine and surgery. The final consideration for many veterinarians is not whether to wait to use laser energy, but instead to understand which wavelength is most effective for their specific needs.

A wide range of wavelengths, including, CO2, Diode 810 nm and 980 nm, (ND, Hol, Erb)YAG, and Low Level Laser Therapy units are being advertised and are available.

A variety of hardware capable of economically producing these wavelengths via different and similar delivery systems are also filling the veterinary marketplace and vying for veterinarians' limited technology funds. Each wavelength provides a specific laser energy to be used by the practitioner to affect targeted tissue. Each wavelength produces a specific effect on certain target components of the targeted tissue. The specific positive effect on the target tissue and any potential negative or positive effect on the surrounding tissue are what the veterinary practitioner must have a good working knowledge of before implementing the use of laser energy for treating patients. Once the practitioner has a thorough knowledge of the tissue-wavelength interaction they can adapt various delivery systems and wavelengths offered to their specific needs.

Photo 4: 40-watt articulated arm CO2 laser, Lumenis, Inc, Santa Clara, Calif.

Delivering laser energy

A growing number of competing laser manufacturers and reseller companies offer various wavelength and delivery systems. Laser company experts tout the specific laser wavelength technology their company produces and the delivery system they supply as the best and most versatile for the general and specialty veterinary practitioner. It is important that veterinarians currently using laser energy or seeking to begin using lasers in their practice first understand the critical physical properties that govern how a specific wavelength of laser energy effects mammalian tissue. Then it is important to understand that there is no one best laser wavelength for veterinarians to use. There is the best selection of laser energy to be made by the practitioner for the specific surgical or therapeutic goal desired. From routine procedures such as the ovariohysterectomy to delicate and challenging neurosurgery, the wrong wavelength of laser energy can produce less than the anticipated therapeutic results, disappointing the practitioner, the client and, most importantly, the patient. It is paramount to impress upon the veterinary practitioner the critical need to understand laser physics and safety before implementing the technology. This is key to a successful relationship between the veterinary practitioner and laser energy.

Selecting the delivery system that best fits your specific practice and budget is also very important for the laser surgeon. The technology must be able to provide reliability, precision, reproducible tissue effects and economy for a reasonable price. CO2 wavelength lasers can provide power outputs from 2 to 100 watts for medical use. They are produced in two primary delivery forms. The most popular is the hollow wave guide energy directed system (Photo 3) that focuses the laser energy via a reflectively coated tube to a handpiece and ceramic or metal tip of varying diameter. The second most popular is the articulated arm energy-directed system (Photo 4) that focuses the laser energy via reflective mirrors positioned at joint articulations directed toward an optically focusing handpiece able to produce specific focused diameter laser beams. These systems vary in how the CO2 laser energy is physically transmitted to the target tissue and how the beam geometry is manipulated to provide sufficient laser energy to the target tissue. Articulated arm delivery systems can typically provide greater total laser energy to the target tissue, but have a reduced ability to be used in very small or delicate locations. Conversely, the hollow wave guided laser energy delivery systems have a maximum output capacity available to avoid damaging the tips, but are able to be used for more delicate and precise techniques or in much more recessed areas. Intra-operatively the handpiece/tip systems may allow for more flexibility in tissue handling during procedures. Focusing optical hand pieces may provide greater power for faster and deeper single pass incisions. Each type provides for excellent tissue vaporization and consistently reproducible effects on the target tissue. The addition of true super pulsing of the CO2 laser energy provides for extremely small peripheral tissue injury or damage.

Photo 5: Diovet 25 watt, 980 nm Diode laser, B and W Tech., Inc., Wilmington, Del.

Diode lasers (Photo 5, p. 22) are produced via solid state semiconductors that dial in the specific wavelength of laser energy in the 635 nm to 980 nm ranges. The diode lasers with the most significant indications for veterinary medicine are in the 810 nm to 980 nm range at power outputs of 1 watt to 60 watts. The laser energy is transferred from the housing to the target tissue via a solid fiber-optic delivery system. Fibers vary in size typically from 400 um to 800 um. The greatest advantage to this type of system is the ability to deliver laser energy to tissue through ports in fiber optical devices and in aqueous environments. Certain Diode laser energies also provided superior coagulation ability in areas of significant vascular flow. These solid quartz fibers can be repeatedly cleaved to provide optimal release of the laser energy into specific target tissue. The Diode laser can also be used in contact or non-contact modes. In non-contact mode the laser energy (25-60 watts) is directed out of the solid wave guide to interact with the target tissue via vaporization similar to CO2 laser energy (5-100 watts). In contact mode the laser energy (5-20 watts) is transferred to heat via carbonization of the cleaved solid quartz, sapphire or dual use fiber wave guide fiber. The photons strike the carbonized surface and transfer their energy to heat, which can be used to cut or cauterized specific tissues. Diode laser energies have applications including coagulation, vaporization, chromophore-enhanced tissue ablation and PDT therapy. Diode lasers limitations are in the increased variability of tissue interaction seen in the target tissue creating the potential for undesirable peripheral tissue effects. This is due to the fact that the various Diode wavelengths interact with multiple components (hemoglobin, oxyhemoglobin, melanin and water), which vary depending on the specific target tissue.

The Nd:YAG laser is a solid state laser that allows transmittance of its laser energy through selected tissues in addition to being selectively absorbed by the surface tissues. It was one of the first lasers to be used in veterinary medicine due to its ability to provide large power transfer of up to 100 watts through very small optical fibers. The Nd:YAG laser can be used for diffuse solid tumor masses, coagulation of large volumes of tissue and large power placement to very recessed areas in the upper airways. The major disadvantage to this wavelength of laser energy is in its significant peripheral tissue interaction event (thermal injury exceeding 3 mm in most tissues).

Photo 6: Low-level laser device in use. Veterinary Therapy Laser, Model PLLSD0009, American Veterinary Laser, Farmington Hills, Mich.

Holmium Ho:YAG and erbium Er:YAG have recently been used for arthroscopic, angioplasty, discectomy, and urethral or bladder lithotripsy. These wavelengths of laser energy can be delivered through flexible, quartz or polyamide optical fibers. These wavelengths, like CO2, rely on the water component of tissue for absorbing energy to heat the tissue. Due to a lack of continuous wave output at room temperature, these lasers are not readily usable for rapid incision or ablation work. They do have considerable amounts of photomechanical energy giving them value in photodisruptive procedures like lithotripsy. The Er:YAG laser is gaining popularity in the human dental field for its ability to ablate damaged enamel and dentin without injury to the dentin tubules or pain initiation allowing for no local or general anesthesia needed.

Low-level laser therapy also known as photobiostimulation is a photochemical effect on tissue that is produced at very low intensity light energies of 5 to 500 milliwatts (see Photo 6, p. 24). It is theorized that at this energy level promotion of upgraded cellular metabolic function is initiated in damaged or inflamed tissue resulting in tissue repair and/or pain remission. Although there is no direct verifiable data to support this claim, there are numerous anecdotal reports that these types of lasers are promoting skin, connective tissue and bony healing in animals and humans. There are a few limited studies that report modulation of mitochondrial respiration and Adenosine triphosphate synthesis that may lead to a reason for improved wound healing, joint repair or pain reduction to inflamed tissue. Some veterinarians are using commercially available devices to treat surgical wounds, strains, osteoarthritis, and soft tissue and musculoskeletal pain with associated mild nerve injury. More research is ongoing, but the jury is still out on the true effectiveness of these devices for treating veterinary patients.

Future innovations in veterinary lasers

Laser application and utilization is still on the upswing in veterinary surgery. The total truth about the usefulness of various laser wavelengths for a host of hard and soft tissue therapies is still to be realized. Testing and prototype production of combination CO2 and Diode lasers is being fast tracked by some laser manufacturers that see an economic advantage in bundling the two most popular laser wavelengths into one machine. Bone vaporization devices are also being considered to allow for resection or bisection of bone and cartilage to minimize blood loss and avoid peripheral tissue damage. Noninvasive recognition of clinical chemistries such as enzyme levels, mineral, vitamin and endocrine functions is on the horizon. One wavelength of laser energy is introduced to the target tissue or fluid and the luminescent light produced is collected and transmitted to a second fiber that reads the specific value produced to determine a quantitative value for the chemistry in question. Greater refinements in the application of laser energy for soft tissue incision and vaporization is being tested and marketed to the veterinarian. This includes CO2 transmitting diamond scalpel blades and advanced computer controlled pulsing of various laser wavelengths.

Suggested Reading

Conclusion

Laser medicine is here to stay. The long-range usefulness of the technology for enhancing therapeutic, surgical and biochemical considerations will be continually refined and retooled. Practicing veterinarians and industry are leading the way in identifying and using lasers to improve surgical management of cases. Academia must begin to work in concert to bring out the greatest good from this technology to the veterinary profession. Laser light is already shining brightly for the veterinary profession. Making sure the veterinary profession has the right paths to follow that are correctly illuminated will be the critical discussion in the coming months and years. In the end the common goal must be to enhance our professionalism, continually seek to raise our standard of care, and maintain and improve the quality of life for our patients and clients. If this happens we will all be winners in the eyes of our patients and clients.