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 Guidelines for
Surgery in Animals

Definitions: Many protocols require some type of surgical procedure. According the federal guidance, the "standard of care" for animal surgery may vary, according to species and activity. For example:  USDA regulations require higher order vertebrates be managed as strict aseptic procedures, while the Guide accommodates performing surgery on lower order species under "clean" conditions. This delineation is further confused by whether the procedure is considered survival or non survival. Therefore, a few definitions are required, before providing a set of guidelines:

  • Major Surgery: In general, if a mesenchymal barrier is opened (pleura, peritoneum, meninges) or an extensive orthopedic procedure is involved, the surgery is considered major. Examples of major surgery include:

    • Extensive resection

    • Entering a body cavity,

    • Removing organs,

    • Significantly altering normal anatomy,

    • Any procedure where the animal is not expected to return to "normal" after a reasonable post-operative recovery period.


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  • Minor surgery: Any invasive operative procedure in which only skin, mucous membrane and / or connective tissue is resected, (i.e. simple vascular cutdown for catheter placement, implanting pumps in subcutaneous tissue).


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  • Non-survival surgery: These procedures are those conducted on animals which are not allowed to regain consciousness following the anesthesia and surgical procedure (i.e. are euthanatized). If IACUC approved, clean procedures are sufficient for this type of surgery, with any species.


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  • Survival surgery: Any surgery from which the animal recovers consciousness. Aseptic technique must be used for all survival surgical procedures in all species.  Individuals performing survival surgery must be knowledgeable about aseptic surgical techniques and have adequate training and skill to conduct the procedure without causing undue post-operative distress to the animal. All survival surgical procedures on non-rodent mammalian species must be conducted in surgical facilities designed for that purpose and approved by the IACUC (rodent survival surgery can be performed in a laboratory with certain restrictions).


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  • Multiple Survival Surgery: Any protocol that anesthetizes an animal to perform an incision, then recovers the animals, and at a later date re-anesthetizes the animal and recovers the animal. Additional justification is required by the IACUC for any "double surgery" study. If the animal is anesthetized, recovered, anesthetized and then euthanatized without recovering, it is not considered a multiple survival surgery. Additional justification (beyond the normal protocol inquiry) is not required.

Core Animal Surgical Facilities: Specific rooms on the Duke campus are approved for survival surgical procedures on non-rodent mammalian species. These facilities are constructed, maintained, and operated to ensure a level of cleanliness appropriate for aseptic surgery. In addition, they are directed and staffed by trained personnel. Investigators desiring these services should consult the DLAR Operations Manager to select and schedule the appropriate rooms.  Generally speaking, all surgeries of non-rodent species, must be conducted in a surgical operating room. Exceptions to this policy include:

  • If the animal will not regain consciousness post-operatively, (i.e. non-survival surgery of any species)


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  • All procedures on rodents, both survival and non-survival, may be conducted in a laboratory.

Pre-Surgical Planning: Successful surgery includes proper surgical planning. Proper planning means adequate assessment of patient and experimental needs, discussion of the surgical plan with the surgical team prior to initiating anesthesia, and preparation of the surgery room and instruments.

Pre-Surgical Fasting: While there are species and procedural difference that would modify this guidelines, in general terms:

  • Rodents & Rabbits (mice, rats, guinea pigs, hamsters, rabbits):  Should not be fasted before surgery.  Their high metabolic rate requires a ready food and water source to keep the animal healthy.  Additionally, rodents DO NOT have a vomit reflex, and therefore cannot regurgitate during surgery.


  • Monogastric animals (e.g. dogs, cats, swine) should be fasted for 6-24 hours prior to surgery.


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  • Ruminants (e.g. sheep, goats, cattle) should be fasted for 24-48 hours prior to surgery. Fasting animals should still have free access to water. Restricting water results in dehydration and more difficult anesthesia.

Rodent Survival Surgery: Post-operative infections in rodents can and do occur. Such infections, which may not be apparent on casual observation, may cause distress to the animals and may affect the results of a study. Aseptic surgical procedures must always be used, however this does not always mean complete gown, mask, etc in a surgical suite. A separate room used primarily for aseptic procedures is desirable; however, the IACUC will approve performing survival rodent surgical procedures in a conventional laboratory setting using aseptic technique. The following are minimum standards for aseptic procedures:

  • A clean uncluttered work area and a disinfected work surface.

  • Appropriate preparation of the surgical site including removal of the hair and disinfection of the skin.

  • The use of sterile instruments, supplies, and wound closure materials.

  • Draping the surgical site with sterile drapes to avoid contamination of the incision, instruments, and supplies.

  • Sterile gloves and a surgical mask should be worn by the surgeon and any assistants working in the immediate surgical field.

  • Surgical procedures may be performed on multiple rodents during a single session using one sterile surgical pack, providing care is taken to minimize contamination and the instruments are soaked in an approved sterilant and rinsed in sterile saline, or flamed with 95% alcohol between animals (soaking in 70% alcohol IS NOT ACCEPTABLE as a sterilant). If appropriate precautions are taken to minimize contamination of surgical gloves, it is adequate to rinse the gloves with a sterilant between rodents. If surgical gloves become contaminated by handling non-sterilized items, they will be replaced with sterile gloves.

Sterilization of Instruments and Supplies: Survival surgical procedures on all mammalian species must be conducted using aseptic technique which requires the use of sterile instruments and supplies. Many supplies such as gloves, surgical blades, and suture materials are commercially available in sterile packs. It is frequently necessary to sterilize, in-house, items such as surgical instruments, drapes, gowns, and instrumentation and catheters for chronic implants.

Post-Surgical Care/Observation: The principal investigator is primarily responsible for post-operative care of the animal. However, investigators may, and are encouraged to, request Duke veterinarians and animal health technician to assist in the responsibility. Certain aspects of this responsibility include:

  • Adequate post-procedural monitoring: Following survival surgery, all animals should be closely observed for the initial 24-48 hour post-surgical period (Post-Procedural Monitoring Forms are available on this web site.  Select FORMS; MONITORING: POST-PROCEDURE on the menu to the left).  It is important to assess whether or not the animal has returned to normal behavior (i.e. eating, drinking, activity). Animals which do not return to normal often have surgical-related infections/complications and require re-evaluation. Surgical incision sites must be observed for the first 48-72 hours post-surgery for clinical signs of infection or suture breakdown. Adequate blood levels of a specific antibiotic should be present at the time of surgery to be most effective in preventing surgery-related infections.


  • Adequate analgesic support: All animals subject to major surgery must have analgesic agents (i.e. painkillers) available to them for at least the initial 24-48 hours post-surgery. Several analgesics are available for a variety of species. The analgesic that should be used depends on the species and "severity" of the surgical manipulation. If the use of analgesics would interfere with the experimental design, prior IACUC approval must be obtained.


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  • Suture / staple removal:  Generally speaking, all sutures / staples MUST be removed by 14 days of the procedure (Most sutures should be removed by 10 days).  Often it is appropriate to remove some sutures / staples as early as 3-5 days, leaving the required ones for a longer period of time for complete closure.  The goal of the staples / sutures are to keep the skin margins closed (thereby discouraging infection, or the risk of infection), while not allowing the staples / sutures to become a nidus for infection or distress to the animal.  Sutures  / staples do have a defined life span, after which they are not needed, and can only serve to cause problems for the patient and the research data.  Exceptions to the standard removal procedures can be requested by the IACUC on a case-by-case basis.