Guidelines for Surgeries on Non-USDA Rodents and Other Species Used in Research or Teaching

A surgery is defined as a procedure in which an incision is made on a live, anesthetized animal. Survival surgeries are those in which the animal recovers from anesthesia, while animals are euthanized without recovery for non-survival surgeries. 

Major surgeries are determined by a high level of invasiveness, such as exposing a major body cavity, extended recovery periods, and an increased risk of complications. 

Minor surgeries are those that do not qualify for the definition of major surgeries. These surgeries are considered lower risk, do not expose a body cavity, and cause little or no physical impairment. 

All procedures involving survival surgery in vertebrate animals must be performed using aseptic technique. They must have an appropriate selection of anesthetic agents and doses as well as a plan for perioperative analgesic use. Any person performing surgery should be appropriately trained prior to performing  work on live animals. This training must be documented within the approved IACUC animal use protocol. Principle Investigators are required to maintain detailed training records for each person approved for activities outlined in the IACUC-approved animal use protocols. For training and additional resources and support contact the IACUC Office.

• Research bred mice and rats, fish, reptiles, amphibians, and birds undergoing survival surgery do not require a dedicated surgical room; however, there should be a designated preparation area within the room separated either spatially or temporally from the surgical area.
• The surgical area should be clean and uncluttered. 
• All surfaces should be impervious and sanitizable. 
• Cardboard and paper products should not be stored in the surgery area. Plastic containers may be used for storage if needed

• All instruments used in survival surgeries should be cleaned and sterilized prior to each procedure. Acceptable sterilization:
  • Autoclave
  • Ethylene oxide (EtOH)
  • Cold sterilants are not recommended but may be used if manufacturer’s instructions are followed and the instruments are properly rinsed prior to contacting the patient.
  • Other methods approved within the IACUC protocol on a case-by-case basis.
• Instruments may be resterilized using hot bead sterilization. This technique is referred to as the “tips only” method.
  • Instrumentations must be sterilized via autoclave or ethylene oxide prior to the first surgery.
  • Only acceptable in certain circumstances, such as rodent survival surgery conducted on multiple animals in a day.
    • Maximum of 5 animals per instrument before autoclaving or EtOH is needed.
  • May be utilized in surgeries where only the tips of the instruments enter the surgical site. Only instrument tips may come into contact with sterile suture or other materials used at the surgical site. 
  • New sterile pack should be open any time overt contamination is encountered (i.e. contact with unprepped skin or intestinal contents)
  • Adherent tissues or any debris on instruments should be rinsed with sterile water, not saline, prior to reinsertion into beads for next procedure.
  • Sterile gloves are not required in this instance because they never come into contact with the surgical site, however, this requires specific training in this particular aseptic technique. 
  • If used, tips only technique should be described in the approved IACUC protocol.  
• Proper instrument and suture selection should be made in consideration for the procedure. Reach out to the UAV for resources on proper selection.

• All hair must be removed from the anticipated surgical site, leaving extra room to prevent accidental contact with the sterile surgical field. Hair may be removed by surgical clippers, hair removal creamers, or other methods approved on the protocol.
• Animals must be aseptically prepped prior to surgery – typically involving three alternating scrubs of chlorhexidine (or an appropriate disinfectant) and 70% alcohol (or an appropriate rinse).
  • Minimum contact time of 2 minutes for chlorhexidine should be considered.
• Supplemental heat must be provided to prevent hypothermia for any surgeries lasting greater than 15 minutes. Direct contact with the heat source must be avoided.
  • Recommended heat sources include: forced air warming system, fluid warmers, hot water recirculating pads, heated surgery table tops.
  • Electric heating pads and blankets are not recommended due to potential dangers to patient safety.   
• Sterile eye lubrication must be provided to any patient anesthetized greater than 15 minutes to prevent corneal desiccation.
• In order to preserve a sterile field and avoid surgical site contamination, the prepared area should be draped or otherwise protected from potential contamination.

For major survival surgeries on rodents and non-mammalian vertebrates, surgeons should thoroughly clean hands and don individually wrapped, sterile surgical gloves and surgical masks. In some instances (e.g. “tips only” technique), sterile gloves are not required; however, this requires specific training in this particular aseptic technique.

• Intraoperative monitoring of the animal’s vitals, plane of anesthesia, timing, route, and dose of drugs/agents administered, and experimental procedures performed are essential components of perioperative monitoring and documentation.
• Anesthetic depth must be confirmed prior to incision. In many species, including rodents, this may be confirmed by performing a “toe pinch” prior to incision. No response to stimuli indicates the animal is ready for surgery. 
• Animals should be monitored for respiration, color, anesthetic depth, temperature, and any additional criteria as described in the approved IACUC protocol. 
• Hydration level should be assessed in all animals. Any prolonged procedure should provide supplemental fluid therapy to the patient.
• For survival surgeries the body cavity must be closed with a protocol-approved method.
• Surgical records must be available for IACUC review.
• Group records are adequate for rodents and non-mammals undergoing the same procedure on the same day. Records should be retained in the animal housing room, or in an accessible location, to facilitate postoperative observation and care.
• For procedures lasting more than 30 minutes, results of intraoperative monitoring (minimally, heart rate, respiratory rate, body temperature and depth of anesthesia) should be recorded every 15 minutes.
• For non-survival procedures longer than 15 minutes, PIs must document the use of anesthetic and tranquilizing agents and intraoperative monitoring procedures.
• Records must include at least the following:
  • Date of procedure
  • Animal identification
  • Surgeon and PI names
  • Brief description of procedure
  • Confirmation of anesthetic depth (example toe pinch)
  • Time of induction and completion of anesthesia
  • All drugs administered, including dose, time, and route of administration

• Immediately following surgery/anesthesia, animals should be placed in a clean, dry, and quiet environment where they can be observed closely by appropriately trained personnel while they recover from anesthesia
• Animals should be monitored continuously until recovered or extubated, or until there is a strong swallowing reflex.
• All food and water bowls and any other physical hazards should be removed from the cage/pen where the animal is recovering from anesthesia.
• Ambient temperature should be adjusted accordingly (bair hugger, circulating water pad, heat lamp or warming board) to maintain normal body temperature. Heating pads are not recommended. Animals generally should not be left unattended with a warming device. Rodents may be left unattended if they are ambulating and have the option to escape the heat source.
• The anesthesia or medical record during this period must document at least the following:
  • Extubation timing if applicable
  • At minimum, heart rate, temperature, respiration rate, and sedation level
  • Clinical abnormalities
  • Any treatments given (drug dosages and route of administration)
• The animal must be fully awake and ambulatory prior to returning to its home cage in the animal housing facility. 
• Rodents – Animals that are not fully ambulatory should be placed in a clean, dry cage with no other rodents and partially on a heat source. Once animals are awake they can be returned to be with their original cagemates.
• Any external closure that requires removal must be removed within the appropriate time frame.
• Monitoring of the animal must continue at appropriate intervals (as described in the IACUC-approved animal use protocol) throughout the postoperative period, which extends until the removal of sutures and the observation that incisions are healed. Monitoring may include:
  • Appetite and eliminations (urine and feces)
  • Abnormalities of surgical site (sutures, bandages, etc.)
  • All treatments given (drug dosages and route of administration)
• The post-operative and/or medical record during this period must document at least the following:
  • Periodic documentation of observation and normal recovery (as outlined in protocol)
  • Any clinical abnormalities
  • All treatments provided (including drug, dosage and route of administration)
• If the animal is normal and skin sutures are removed, specific post-surgical care and records are no longer required
• If progress in recovery from anesthesia or surgery is not as expected or if there are medical complications, veterinary staff should be contacted immediately.