Guidelines on the Performance of Surgery in Non-Rodent Mammals

Unit for Laboratory Animal Medicine
Aug 5, 2020 12:00 am

This document is intended to provide guidelines for investigators who perform surgical procedures in non-rodent mammals including dogs, cats, swine, ferrets, rabbits, ruminants and non-human primates.

All surgical procedures, anesthetics, analgesics, antibiotics or other medications used on animals must be approved by the IACUC, described in the animal use protocol, and performed by personnel listed on the protocol and appropriately trained for the surgical procedure.

  • Definitions

    1. IACUC: Institutional Animal Care and Use Committee.
    2. Procedure
      1. A manipulation of an animal that does not involve an incision that needs closure.
      2. Procedures can be performed for an experimental application, examination purposes, or treatment of an induced or spontaneous disease or condition.  Examples of procedures include:
        1. Injections
        2. Bandaging/casting
        3. Imaging
        4. Antibody production
        5. Blood/fluid collection
        6. -Oscopies into natural opening that do not involve biopsy
        7. Non-invasive physiological monitoring
        8. Small tissue biopsy without cavity exposure
        9. Bone marrow aspirate
    3. Minor Recovery Surgery
      1. A surgical intervention that does not expose a body cavity or does not ordinarily have the potential to result in impairment of a vital physical or physiological function.
      2. Examples of minor survival surgeries include:
        1. Cranial burr holes that do not expose dura or brain
        2. Subcutaneous implants
        3. Peripheral vessel cannulation (peripheral approach)
        4. Castration (scrotal or prescrotal approach)
        5. Oral surgery and tooth extractions not involving bone
        6. -Oscopies into natural openings that involve biopsy
        7. Small digit or tail amputation
        8. Surgical repair of superficial injury
    4. Major Recovery Surgery
      1. A surgical intervention that penetrates a body cavity (i.e. cranial, thoracic, abdominal, synovial, pelvic, ocular or orbital, skeletal, joint or bone marrow), involves extensive tissue dissection or transection, or has the potential for producing a substantial impairment of a physical or physiological function.
      2. Examples of major survival surgeries include:
        1. Tendon/ligament repair or injury
        2. Ovariohysterectomy
        3. All --otomies (e.g., lararotomy, tracheotomy) and --ectomies
        4. -Oscopies that involve incision (e.g., laparascopy)
        5. Implantation of central devices
        6. Amputation
        7. Enucleation
        8. Eye surgery involving corneal incision
        9. Central cannulation (central approach)
        10. Musculoskeletal system repair, injury, or biopsy
        11. Extensive tissue dissection/transection (e.g., nerve or muscle cut-down)
      3. Some surgeries may be classified as major or minor depending on various factors, and may be evaluated on a case-by-case basis.
        1. Factors that can influence the classification may include the duration of anesthesia, size and location of the incisions, amount of tissue dissection, and characteristics of the animal to undergo surgery.
    5. Non-Recovery Surgery
      1. A surgical intervention in which an animal is euthanized before recovery from anesthesia.
  • Procedures

    1. Documentation

    1. Anesthetic and post-surgical monitoring records are required for every non-rodent mammal covered by the USDA that has undergone surgery.
    2. Maintain records within the animal room or immediately adjacent to the animal room for 7-10 days until closure methods have been evaluated and/or removed.
      1. Sutures
      2. Wound clips
      3. Staples
      4. Tissue adhesive
    3. Documentation requirements in records include:
      1. Full names of all drugs/substances administered during the procedure/surgery.
      2. Dosage and frequency of administration.
      3. Frequency of monitoring by investigative or veterinary personnel.
      4. Determination of any pain or distress in the animal if “as needed” analgesics are withheld.
      5. Sample monitoring records are provided in Appendix A.
    4. Once the post-operative monitoring period is over, records must be copied and turned into the ULAM Veterinary Technician Office for filing with the animal's permanent medical records in accordance with the Guidelines on Medical Records for Investigative Personnel.

    2. Preparation of the Procedure/Surgical Room

    1. A dedicated, IACUC-approved surgery room is required for major recovery surgeries and includes separate area(s) for preparation of the patient and surgeon and a separate area for surgical recovery.
    2. A dedicated, IACUC-approved procedure area is required, with separate prep and recovery areas strongly recommended for minor surgeries.
      1. Ensure no other activities are occurring in the dedicated, IACUC-approved procedure area during the minor recovery surgery (i.e., a dedicated procedure room that has no other simultaneous activities present).
    3. All major and minor surgical and procedure rooms need to be kept clean and maintained in a manner to minimize traffic flow.
    4. It is imperative that the surgical room be at an appropriate level of hygiene before major survival surgeries are performed.

    3. Preparation of Instruments, Devices, or Supplies for Aseptic Procedures/Surgeries

    1. Instruments or medical devices used in minor or major recovery surgeries must be sterilized either with steam sterilization, vaporized hydrogen peroxide, or ethylene oxide. Alternatively, some instruments can be purchased already sterilized, using the above methods or by other methods (e.g. gamma irradiation).
    2. Vaporized hydrogen peroxide or ethylene oxide can be used to sterilize heat or pressure sensitive instruments, devices, or supplies.
    3. Appropriate sterilization indicators should be used with all methods of sterilization for validation. Appropriate testing and maintenance should be performed for all sterilization equipment.
    4. Begin with a fully sterilized pack of instruments for each surgical animal when performing multiple aseptic procedures or recovery surgeries in series. Ensure an extra pack is available in case of unexpected contamination.
    5. Surgical Drapes:
      1. Sterile drapes may be used for wrapping the instrument packs and/or creating the sterile field about the incision site.
      2. Drapes can be cloth, paper, or 3M™ Steri-Drape™ Incise Drape or other suitable sterile material.
      3. Drapes and similar materials must be sterilized prior to use on the animal.

    4. Preparation of the Animal

    1. Fasting: See the species-specific anesthesia and analgesia guidelines and/or discuss with the faculty veterinarian for recommendations.
    2. Anesthesia
      1. Information regarding appropriate anesthetic choice and minimal monitoring requirements can be found:
        1. Anesthesia and Analgesia Drug Descriptions
        2. Anesthesia and Sedation Monitoring Guidelines
      2. Several non-rodent mammal species-specific anesthetic and analgesic guidelines are available and include more detailed information on anesthetic/analgesic doses as well as recommended routes of administration. Links to these guidelines are as follows:
        1. Guidelines on Anesthesia and Analgesia in Cats
        2. Guidelines on Anesthesia and Analgesia in Dogs
        3. Guidelines on Anesthesia and Analgesia in Ferrets
        4. Guidelines on Anesthesia and Analgesia in Guinea Pigs
        5. Guidelines on Anesthesia and Analgesia in Hamsters
        6. Guidelines on Anesthesia and Analgesia in Nonhuman Primates
        7. Guidelines on Anesthesia and Analgesia in Rabbits
        8. Guidelines on Anesthesia and Analgesia in Ruminants
        9. Guidelines on Anesthesia and Analgesia in Swine
    3. Hypothermia Prevention: An external heat source (such as a circulating water blanket or Bair-Hugger®) MUST be provided when the duration of anesthesia will be >10 minutes or for any procedure in which a body cavity is exposed.
      1. More information on appropriate thermal supplementation and monitoring can be found in the Anesthesia and Sedation Monitoring Guidelines.
    4. Sterile ophthalmic ointment (such as Puralube) MUST be applied to the eyes when animals are anesthetized for >5 minutes.
    5. Vascular access: Animals undergoing anesthesia for periods longer than 30 minutes should have available vascular access by way of an IV catheter.
      1. Isotonic fluids (such as LRS or 0.9% NaCl) at a rate of 5-10 mL/kg/hour should be given if prolonged body cavity exposure or significant blood loss is expected.
    6. Hair Removal: Remove hair from the surgical site with animal clippers, razor or a depilatory cream (Nair®).
      1. Surface area and contact time should be minimal when using a depilatory cream to prevent chemical irritation and increased risk of infection.
      2. Thoroughly rinse depilatory cream off before disinfection of the skin.
    7. Skin Disinfection at Surgical Site: Clean and disinfect the animal's skin using appropriate surgical preparation technique with a recommended skin disinfectant (chlorhexidine, iodine, etc.).
      1. Alternating circular (inside to outside) scrubs of disinfectant (chlorhexidine scrub, iodine scrub, etc) and rinse (warmed sterile saline, sterile water, or alcohol) should be performed for a minimum of three times after removal of visible dirt and debris.
    8. Placement and Draping:
      1. Ensure the animal is appropriately secure on a covered surgery surface before covering with a sterile drape.
        1. Use cushions on pressure points is recommended for larger species to decrease likelihood of associated neurological trauma.
        2. Leg ties, positioning pads, sand bags, disposable foam cushions, etc may be used to position the animal.

    5. Personnel Preparation

    1. Refer to EHS Animal Handler PPE Chart if alternate PPE accommodations are necessary.
    2. For Major Survival Surgeries:
      1. Perform a surgical scrub on the hands and lower arms using sterile scrub brushes and/or an approved waterless surgical solution (such as AvagardTM) before gowning and gloving.
      2. Required attire for the surgeon during the surgical procedure:
        1. Sterile gloves
        2. Sterile surgical gown
        3. Mask
        4. Hair bonnet or surgical cap
        5. Shoe covers
        6. Clean scrubs
      3. Don a new pair of sterile gloves for each animal and change sterile gloves if contamination is suspected or observed.
      4. Remove jewelry from hands, wrists, arms, and loosely hanging earrings.
      5. Ensure other personnel present within the room while the surgery is in progress are wearing:
        1. Dedicated outer covering
        2. Shoe covers
        3. Mask
        4. Surgical cap or bonnet
        5. Don gloves if touching the animal or the animal’s biological substances.
    3. For Minor Survival Surgeries:
      1. Required attire for the surgeon during the procedure:
        1. Mask
        2. Surgical cap or bonnet
        3. Sterile gloves
        4. Clean scrub top, clean disposable PPE gown, or clean lab jacket
      2. Don a new pair of sterile gloves for each animal and change sterile gloves if contamination is suspected or observed.
      3. Remove jewelry from hands, wrists, arms and loosely hanging earrings.
      4. Ensure other personnel present within the room are wearing a:
        1. Dedicated outer covering
        2. Mask
        3. Surgical cap or bonnet
      5. Investigative personnel working with pregnant ewes must wear an appropriate respirator in place of a surgical mask and sealed eye protection.
        1. See Procedures to Reduce Human Exposure to Orf and Q Fever and the EHS website (
      6. Investigative personnel working with non-human primates must wear sealed eye protection and 2 layers of gloves. A respirator should be used for activities that create an aerosol risk.
        1. See EHS website (
      7. Ensure appropriate training and shielding is completed and utilized if radiation is used during the procedure.
        1.  See EHS website (

    6. Suture Materials & Wound Closure

    1. Select sterile suture material (absorbable vs. non-absorbable; braided vs. monofilament) that is appropriate to the tissues, procedure and activity of the animal.
    2. Surgery in which a body cavity is opened requires a 2-3 layer closure in which the body wall is closed separately from the skin.

    7. Post-operative Monitoring & Care

    1. Animals must be visibly observed and monitored continuously until removal of the endotracheal tube and then every 15 minutes during recovery until the animal is fully ambulatory.
      1. Required and recommended post-operative monitoring parameters can be found in the Anesthesia and Sedation Monitoring Guidelines.
      2. External thermal supplementation should be continued during the post-operative recovery period. More information regarding appropriate external devices can be found in the Anesthesia and Sedation Monitoring Guidelines.
      3. Detailed information for normal physiologic parameters can be found in the species-specific anesthesia and analgesia guidelines.
    2. Administer post-operative medications including analgesics, antibiotics and/or anesthetic reversals according to the IACUC approved protocol or on the advice of a ULAM veterinarian.
    3. Administered during the early recovery period when possible.
    4. Place a yellow acetate with Surgery Observation Sticker over the cage card when the fully recovered animal is returned to the animal room.
      1. Record the date of surgery and the date for removal of wound clips, staples, or skin sutures on the sticker.
      2. If the skin is sealed with glue, a yellow acetate with a Surgery Observation Sticker must be placed over the cage card with the date of surgery recorded and the date the yellow acetate will be removed. The acetate will need to be removed 7-10 days after surgery provided the incision is adequately healed.
      3. Remove the acetate once the 7-10 day monitoring period is over.  See Procedures section 7.d for further information.
    5. Remove wound clips, staples or skin sutures within 7-10 days (provided the skin incision is adequately healed) unless described otherwise in an IACUC approved protocol or as recommended by a ULAM veterinarian to necessitate incomplete wound healing.
      1. Adequate healing is described as apposed wound edges without signs of dehiscence, increased redness, discharge, odor or overt swelling.
    6. Record daily post-operative monitoring and health status of the animals during the post-operative monitoring period and maintain in the animals' surgical documentation records.
      1. Document the full name of the drug/substance administered, dose administered, and route of administration on the post-operative records.
      2. Document during the post-monitoring period if the animal is not showing clinical signs of pain and no analgesic therapy was needed (e.g., "No clinical signs of pain observed, analgesics not administered.")

    8. Non-Survival Surgery

    1. The surgical site should be clipped, the surgeon should wear gloves, and the instruments and surrounding area should be clean and free of clutter.
    2. For non-survival procedures of extended duration, attention to aseptic technique may be more important in order to ensure stability of the model and a successful outcome. The requirement to utilize forms of aseptic technique, surgical monitoring, and a IACUC approved surgery suite is evaluated on a case-by-case basis by the ULAM veterinarian(s) and IACUC prior to approval.
  • Appendix A: Non-Rodent Mammal Post Op Record

  • Appendix B: Non-Rodent Mammal Intra-Operative Monitoring Form