Rodent Surgery and Illumination
Posted by: admin | December 30, 2009 | 0 Comments
Recently, we brought up magnification as an aspect of rodent surgery which is commonly taken for granted. Illumination/lighting is just as important. Many rodent surgeons who perform procedures such as jugular or carotid catheterizations perform them without the assistance of illumination. When a light source is utilized, it is commonly an incandescent light such as a desk lamp. When performing rodent surgery it is imperative to ensure a brightly lit operative field. This improves the visibility for the surgeon, which is especially important during rodent microsurgery when appropriate illumination decreases eye strain. Eye strain can lead to fatigue and poor surgical outcomes, particularly when multiple surgeries are carried out within the same day. It has been demonstrated that surgical time for vascular anastomoses is shorter when a bright operative field is used in comparison to a poorly lit operative field.
When a light source is utilized, it is important to consider factors such as the type of light source, the intensity, duration, distance of projection and focusing ability.
Initially the standard light source for surgery was an incandescent light source. The halogen light bulb was then introduced followed more recently by the xenon. The challenge with an incandescent light source is that although it emits tremendous amount of light, the light accounts for a small percent of their energy output. The rest of the energy is emitted as heat. The heat can desiccate and cause thermal damage to tissues. The halogen and xenon lights, when combined with fiber optic cables, produce less heat and are considered a cold light source. However, these fiber optic cables only reduce the amount of infrared radiation, which is usually associated with heat production, with respect to visible light. This heat reduction is accomplished with special filters or reflectors. Radiation in the visible and infrared wavelengths enters the fiber optic cable and is transmitted through the cable. When the light leaves the end of the light source, the level of infrared radiation is usually reduced to a safe level through absorption by the optical fibers and through substantial losses at the cable connections. The advantage of a xenon light source is that it produces a bright and clear operating field. However it has been reported that a xenon light at 300 watts at working distances as great as 20 cm with prolonged exposure can lead to thermal tissue damage. Thermal damage and tissue desiccation can be prevented by keeping tissue moist.
The halogen light source which is not as bright as xenon is preferred for ophthalmologic surgeries since the brightness of the xenon lights can be phototoxic.
It is our assertion that illumination during rodent surgery enhances visual acuity which should be regarded as an asset during any rodent surgical procedure.