Guidelines for Aseptic Surgery in Rodents

Background/Purpose

The Guide states that, “Aseptic technique is used to reduce microbial contamination to the lowest possible practical level." Aseptic technique includes preparation of the patient, such as hair removal and disinfection of the operative site; preparation of the surgeon, such as provision of decontaminated surgical attire, surgical scrub, and sterile surgical gloves; sterilization of instruments supplies, and implanted materials; and the use of operative techniques to reduce the likelihood of infection.”

Surgical Planning

• Rodent surgery can be performed in a non-dedicated surgical suite. However, the surgery should be done in a clean, well-lit, uncluttered table or bench surface with a minimal traffic.
• No other activities can be performed in the same area while surgery is being performed.
• The surface should be cleaned with disinfectant (10% Clorox, Lysol) before and after use.
• Ensure all the supplies including the instruments, drugs, and medical devices are available prior to scheduling the surgery.
• Ensure a surgical assistant/assistance is available for assisting with the procedure.

Preparation of the Animal

• The animal should be assessed for normal well-being including a smooth, glossy hair coat, good body condition, and a normal, unobstructed breathing pattern.
• Fasting in rodents is not recommended. However, if gastrointestinal surgeries are planned fasting for a few hours prior to surgery may be helpful.
  Note: Rodents cannot vomit.
• Anesthetize the animal using anesthetic agents described in the approved protocol. Do not change the route or the type of agents used.
• Check the anesthetic depth of the animal using toe pinch or righting reflex. If adequately anesthetized, it will be evident from the lack of response to the noxious stimulus or the toe pinch.
• Clip the hair from the surgical site with clippers (#40 blade) or use a depilatory cream (Nair). This should be preferably done away from the surgery table.
• Prepare the surgical site with a disinfectant scrub using chlorhexidine/or povidone iodine and 70 percent alcohol alternatively for three times followed by a final povidone paint.
  • During the scrub, always start from the center of the surgical incision site to the periphery. Don't bring the scrub or sponge from outside/periphery to the center.
  • Avoid contamination of the sterile surgical field during subsequent positioning of the animal.
• Avoid hypothermia – Don't use alcohol or the scrub excessively.
• Apply eye lubricant (petroleum jelly) to prevent corneal dryness or desiccation. Due to the lack of blink reflex together with reduced eye lids, the rodents are prone to corneal dryness.
• Drape the surgical sites using sterile drapes.

Preparation of the Surgeon

• The surgeon must wear a clean lab coat or scrubs over their regular street clothes.
• The surgeon should scrub and wash their hands with an antiseptic surgical scrub preparation and then aseptically put on sterile gloves. The commonly used surgical scrub includes Betadine® or Nolvasan® .
• The surgeon should wear a surgical face mask. A surgical cap and gown are recommended, but not required.
• Note: Though not recommended, if working alone, the surgeon should have the animal anesthetized and positioned and have the first layer of the double-wrapped instrument pack opened before putting on sterile gloves.
• Sterile gloves should be changed between surgeries and when in contact with non-sterile areas.

Instrument Sterilization

• All surgical instruments, including gauze, suture materials and medical devices should be sterilized prior to use. The method of choice may be determined by the surgical instruments or devices being used.
  • Steam sterilization may be accomplished by autoclaving at 121º Celsius for 20 minutes. Gas sterilization with ethylene oxide is an alternative for items which will not withstand high temperatures. Acceptable techniques for cold sterilization include soaking in 2% glutaraldehyde for ten hours, in 8% paraformaldehyde for 18 hours, or in 6% stabilized hydrogen peroxide for six hours.
  • Note: Alcohol is neither a sterilant nor a disinfectant.
• If multiple surgeries are performed in a single day, I recommend the use of separate sterile packs between surgeries. If not possible, the PI should sterilize the instruments using Bead Sterilizer appropriate contact time between surgeries.
• Procedural techniques which encourage proper surgical outcomes include:
  • Gentle tissue handling
  • Minimal dissection of tissue
  • Appropriate use of instruments
  • Effective hemostasis
  • Correct use of suture materials and patterns
  • Reducing surgical time

Any questions about aseptic or surgical technique may be consulted with CCM Veterinary Staff by calling 860-679-2731.

Suture Materials

Extracted From: University of Pennsylvania School of Veterinary Medicine and Family Practice Notebook

Helpful Links

• Drug Guidelines
  • Mouse
  • Rat
  • Rabbit
• Needle Sizes, Sites for Injection, Recommended Volumes for Injection
• Anatomy of a Mouse/Rat Tail