between a Teflon anvil and the vibrating blade. There are two settings, one to seal the tissue and another to cut through the tissue.
Carbon Dioxide Laser
The carbon dioxide (CO2) laser (Aesculight; LuxarCare LLC, Bothell, WA) gained popularity in veterinary surgery in the 1990s and continues to be in common use today. CO2 lasers produce a beam of intense light at a wavelength that is highly absorbed by water molecules. It cuts tissue when the beam is very focused and coagulates for hemostasis when it is more diffused. The CO2 laser seals vessels <0.6 mm, so most skin incisions are bloodless with minimal or no bruising. It also seals lymphatic vessels and nerves so there is less swelling and reportedly less pain associated with incisions compared with those made using a scalpel. When used with correct technique, the amount of lateral heat damage is minimal (Harkness et al. 2010); however, when used incorrectly, lasers can cause significant thermal damage.
In addition to being able to incise skin and other tissues, CO2 lasers can also be used to fulgurate or destroy tissue, such as a tumor or the tissue bed after a tumor has been removed in an effort to eliminate residual microscopic disease. Use a high‐power setting and keep the tip as close to the tissue as possible when cutting tissue. Do not touch the tip to the tissue. If there is hemorrhage, move the tip farther from the tissue, which will diffuse the beam and coagulate vessels. Use a smaller tip to create a small spot of light which will then cut better with less collateral heat. A wider tip will not cut as well and will cause more heat damage, but will also control hemorrhage better by coagulating vessels. Proper safety training for all personnel is important when using surgical lasers.
Magnification
Magnification is a vital part of efficiently performing surgery on small exotic animals, but it is also useful for delicate procedures in any size animal (see Chapter 3).
Focal Light
Overhead surgery lights are not adequate for surgery in small exotic animals and are becoming obsolete being replaced by head‐mounted focal light sources that illuminate whereever the surgeon is looking, including deep into body cavities. These lights illuminate a smaller area allowing better visualization of the tissues. Inexpensive head‐mounted cool focal lights are available with or without magnifying loupes from many sources (LED Headlight; MDS, Inc., Brandon, FL). SurgiTel loupes (General Scientific Corporation, Inc., Ann Arbor, MI) are available with different light options that mount onto the frame to illuminate the surgeon's field of view.
General Scientific Corporation, Inc., also offers SurgiCam HD, a head‐mounted digital video camera with 3× magnification. The procedure can be viewed on a monitor, and images, and videos can be captured onto a computer.
Retractors
In the past, spring‐loaded eyelid retractors have been recommended for abdominal wall retractors in small patients. The tension cannot be adjusted and is often too much for small patients. Heiss and Alm Self‐Retaining Retractors work well as abdominal and tissue retractors in companion exotic animals (Figure 1.5). The Lone Star™ Retractor (Veterinary Specialty Products, Inc., Mission, KS) consists of a plastic frame and silastic bands with tissue hooks on the ends (stays) (Figure 1.6). Be sure to look for the models with all components that are fully autoclavable. Place the stay hooks in the tissue and using an appropriate amount of tension, pull and insert the silastic bands into the notches of the frame to retract tissue. These retractors are very versatile and have a wide range of applications.
Instrumentation
In the past, many surgeons have turned to using ophthalmic instruments for surgery in small exotic animals; however, they are not well suited for this purpose. Being made for surgery on a superficial structure, the eye, they are short making them more difficult to control and to manipulate tissues deep in a body cavity. Microsurgical instruments are manufactured so they are of a standard length and only the tips are miniaturized (Bennett 2009) (see Chapter 3). They are long enough for the instrument to balance in the hand while the tips extend beyond the surgeon's hand into the patient's body cavity (Figure 1.7). They should be counterbalanced to minimize hand fatigue. Round handles are recommended because the instruments should be rolled between the thumb and first two fingers rather than using wrist action. Having round handles is most important for needle holders because the curved needle has to be passed through the tissue using this rolling action between the thumb and fingers. Even with scissors and forceps, it is easier to roll them if the handles are round. Many surgeons prefer needle holders without box lock for delicate tissue because when the lock is set, the needle can jump and tear tissues. Hold a microsurgical instrument as if you were holding a pen (Figure 1.8a). An across‐the‐palm grip is inappropriate (Figure 1.8b). As a starting point, a microsurgical pack should contain a microsurgical needle holder, a microsurgical scissors, and microsurgical thumb forceps (Figure 1.9). Add other microsurgical instruments to the pack with increasing experience.
Figure 1.5 An Alm retractor (a) uses a thumb screw to open the jaws, while the Heiss retractor (b) has a quick release ratchet mechanism.
Figure 1.6 The Lone Star retractor system consists of a plastic ring with notches around the perimeter (a) and silastic bands with tissue hooks that are placed in the tissue to be retracted (b). Insert the bands into the notches in the ring to maintain tissue retraction.
Figure 1.7 Microsurgical instruments should be a standard length with miniaturized tips that extend beyond the hand into the tissue and should be counterbalanced to minimize hand fatigue.
Suction and Irrigation
Ophthalmic bulb syringes work well for tissue irrigation in small exotic animals (Figure 1.10). Alternatively, use a syringe with a needle attached and bend the needle at the hub repeatedly until it breaks off to minimize the risk damaging tissue with the needle. Fine Barron suction tips have a release hole providing two degrees of suction; stronger suction with the hole covered and more delicate suction with the hole
