Survival Surgery

Last Review Date: December 29, 2020



I.  Introduction


Survival surgery is defined as any surgical procedure from which the animal will recover, even if only for a short period of time.  As with any activity involving animals, the individual(s) carrying out the procedure(s) must be adequately qualified and trained before beginning work involving survival surgery. In most cases, it will be necessary for the surgeon(s) to practice basic operative techniques on inanimate models and the specific procedure on cadavers before performing it on a living animal. Even then, the Institutional Animal Care and Use Committee (IACUC) may require additional animals to be used for non-survival training and/or observation and approval of technique by the Attending Veterinarian (AV) or an appropriate representative before any animals may be recovered from anesthesia. Please contact Laboratory Animal Resources (LAR) or the AV to arrange for guidance and practice.

As with any activity involving animals, the individual(s) carrying out the procedure(s) must be adequately qualified and trained before beginning work involving survival surgery. In most cases, it will be necessary for the surgeon(s) to practice basic operative techniques on inanimate models and the specific procedure on cadavers before performing it on a living animal. Even then, the Institutional Animal Care and Use Committee (IACUC) may require additional animals to be used for non-survival training and/or observation and approval of technique by the Attending Veterinarian (AV) or appropriate representative before any animals may be recovered from anesthesia. Please contact Laboratory Animal Resources (LAR) or the AV to arrange for guidance and practice.

In the list below, explanatory information is provided in italics for several requirements. These recommendations intended to assist in the implementation of this policy, as well as enhance the well-being of the surgical patient.

II. Policy

It is a LAR policy to meet or exceed all federal, state, and local regulations and guidelines and to comply with all institutional policies and procedures as they apply to the use of animals in research. LAR personnel or Investigators involved in husbandry and care must pass on-line animal training modules and attend applicable training in animal care and use, occupational health and safety, and equipment operation prior to performing activities outlined in this SOP. Animal housing rooms should be entered using appropriate personal protective gear for the species and disease or hazard containment level

III.  Institutional Recommendations for USDA and Non-USDA Survival Surgery

      A.  Introduction and Procedure Requirements
            The Public Health Service (PHS) and AAALAC International require that survival
            surgeries conducted on laboratory rodents and animals not regulated by the United
            States Department of Agriculture (USDA) be conducted using aseptic technique.
            Survival surgery is defined as any surgical procedure from which the animal will
            recover, even if only for short periods of time.

            As with any activity involving animals, the individual(s) carrying out the procedure(s)
            must be adequately qualified and trained before beginning work involving survival 
            surgery. In most cases, it will be necessary for the surgeon(s) to practice basic
            operative techniques on inanimate models and the specific procedure on cadavers
            before performing it on a living animal. Even then, the Institutional Animal Care and
            Use Committee (IACUC) may require additional animals to be used for non-survival
            training and/or observation and approval of technique by the Attending Veterinarian
            (AV) or appropriate representative before any animals may be recovered from
            anesthesia. Please contact Laboratory Animal Resources (LAR) or the AV to arrange
            for guidance and practice.

            The following explanatory information is provided for surgical requirements at this
            institution. These requirements are intended to assist in the implementation of this SOP
            and enhance the well-being of the surgical patient(s).

       B.  Preparation of the Anesthetic Plan
            An anesthetic plan (in consultation with the AV) should be prepared before
            submission of the Animal Use Protocol (AUP). Ideally, the anesthetic plan is balanced
            (synergistic administration of analgesia and anesthesia) to decrease the required
            flowrate or dose of the anesthetic agent, and increase the anesthetic safety for the
            patient. All required drugs must be purchased and available at the time of surgery.
            Before initiation of anesthesia, all drug dosages [anesthetics, analgesics, reversal
            agents, and emergency drugs (e.g., Doxapram, epinephrine, atropine, etc.)] and
            their volumes must be pre-calculated and written into the anesthetic form or
            laboratory notebook. Pre-calculation of drug dosages and their volumes saves time,
            and animal lives in the event of an anesthetic emergency.

      C.  Preparation of the Procedure Area
            Unlike the requirements for a USDA-dedicated surgical suite [HSB 005 (e.g., degus,
            hamsters, Peromyscus and rabbits)], the non-USDA procedure areas [SB 016A and SB
            035 (mice and rats)] are not required to be dedicated to surgical procedures at all
            times. However, the surgery area and associated equipment must be organized,
            sanitized (Peroxigard®) and dedicated to that purpose while surgery is conducted.
            Contact time of the sanitizing compound with the surface of the surgical area is the
            most critical component of effectively killing contaminating microorganisms. The
            surgery area must be dedicated to that purpose while surgery is conducted. It is
            recommended to clean the surface, then lightly mist the work surface and allow at
            least 1-2 minutes to air dry.

            Cover the surface of the surgical work area with a circulating, warm-water blanket
            and then cover the blanket with clean paper (e.g., plastic-backed lab bench paper)
            or cloth to help prevent hypothermia and absorb fluids. Separate areas (e.g., different
            tables or portions of counters) should be used for patient pre-operative preparation,
            surgery, and post-operative recovery.

            Volatile anesthetic agents must be suitably scavenged using active house exhaust or
            passive charcoal canister. For procedures in excess of 30 minutes, records of drugs
            administered, gas anesthetic flow rate administration, intra-operative physiologic
            monitoring, and postoperative pain medication must be recorded and available for
            inspection upon request

            Procedure durations less than 30 minutes must have a record of anesthetic and
            analgesic drugs administered, time of administration, description of the procedure,
            and duration of the procedure. These records must be available for inspection upon
            request. Use of injectable controlled substances must be recorded on institution-issue
            drug logs.

       D.  Preparation of the Surgical Instruments and Supplies
             Surgical instruments, suture or skin staples, and implants must be sterile before
             initiating the first surgical procedure. Typically, surgical instruments are sterilized by
             steam autoclaving (minimum 121°C, 15 PSI, for 15 minutes), sutures or skin staples are
             purchased in sterile packages or immersed in a sterilant for >20 minutes, and heat-
             sensitive implants or instruments are sterilized chemically (e.g., Cidex,
             glutaraldehyde), gas-sterilized (e.g., ethylene oxide, vaporized hydrogen peroxide),
             or irradiation.

             Depending upon the nature of the surgical procedure and the degree of instrument
             contamination during the surgery, a sterile set of instruments may be used on up to 2-
             10 rodents during the same surgery session. Between animals, the instruments must be
             cleaned of blood and gross debris, and decontaminated using chemical disinfection
             or a point heat source (e.g., glass bead sterilizer). Care must be taken to ensure that
             instrument tips have cooled before using on animal tissue. Chemical sterilants must
             be rinsed from instruments with sterile water or saline before contacting animal tissues
             to avoid chemically-induced tissue damage. Ethanol alone is not sufficient to sterilize
             instruments. If a break is taken between groups of surgeries, instruments should be
             covered with a sterile drape to protect instruments from dust, hair, and air-borne
             environmental contaminants. If the break between groups of surgeries is sufficiently
             long, the instruments should be cleaned, re-packaged, and autoclaved

        E.  Preparation of the Animal

             Food and water are not typically withheld from rodents due to their rapid metabolic
             rates and inability to vomit. After anesthesia is initiated, the surgical site must be
             clipped free of fur. Preferred methods for removal of fur are manual plucking,
             depilatory creams, or shaving with electric clippers. Loose hair should be removed
             with a vacuum, tape, or wet gauze. Skin should be aseptically prepared with an
             iodine (Betadine ®) or chlorhexidine- (Novlasan ®) based surgical soap followed by
             warm sterile water, warm sterile saline, or warmed 70% alcohol (ethyl or isopropyl)
             rinses. Use of sterile cotton-tipped applicators is recommended for small rodents to
             minimize skin wetting that can cause hypothermia. Ethanol should be used sparingly
             to prevent serious, rapid drops in core body temperature. The aseptically prepared
             area should extend beyond the immediate area of the anticipated incision in order
             to minimize the risk of cross contamination, and to allow for safe extension of the
             incision, if necessary.

             Whenever possible, the surgical site should be draped with sterile drapes of cloth,
             paper, surgical gauze, or clear adhesive vinyl (TegadermÒ or Press’NSealÒçGladÒ)
             to minimize contaminating the surgery site, surgical instruments, or the surgeon’s
             gloves. Care should be taken to avoid placing a drape such that the animal cannot
             be monitored. Drapes can have the added benefit of keeping the animal warm.

        F.  Preparation of the Surgeon

             Sterile surgical gloves, a surgical mask, and a clean outer garment (e.g., lab coat or
             scrub top) are required for survival surgery. Surgical gloves and the working surface
             must be cleaned between each animal.

        G.  Surgical Technique
              It is important to minimize the 3 T’s: time, trash and trauma. Time is kept to a minimum
              by planning ahead, organizing equipment, and mastering the procedure to be
              performed. Trash is avoided by keeping instruments sterile, using proper aseptic
              technique, and wearing appropriate protective gear. Trauma is minimized by using
              gentle tissue handling techniques, avoiding chemical-induced tissue damage, using
              sharp instruments, keeping tissues moist with sterile saline, and placing sutures or
              staples to achieve tissue apposition while avoiding excessive tension. A subcuticular
              skin suture pattern will often preclude the chewing and premature removal of sutures
              by the animal.

              Animals should be kept warm using an external heat source, particularly for
              procedures of any significant length (i.e., longer than 30 minutes). A circulating
              warm-water blanket is the safest choice, and there is one available for each
              procedure room in each LAR facility. Great care must be taken to prevent
              overheating or burning the animal when using other modalities. Some heating pads
              for rodents come with a rectal temperature probe that acts as a feedback
              thermostat to turn the pad on and off. Warmed water bottles may be used in
              conjunction with the warm-water blanket and surgical drapes to slow patient heat
              loss. Also, for prolonged procedures, particularly those accompanied by blood loss,
              warmed fluid therapy should be administered. The recommended amount is equal
              to 1-2 cc per 100g body weight per hour of anesthesia plus any blood loss. Because
              of the small size of the patients covered by this policy, the intraperitoneal or
              subcutaneous routes are usually used. During the surgery, the animal's vital signs such
              as pulse rate, oxygen saturation, respiration rate, rectal temperature, tissue color,
              and response to noxious stimuli should be monitored, and recorded serially so that
              corrective action can be taken promptly, if necessary, and an anesthetic record is
              generated. An appropriate anesthetic record form can be obtained from the AV.

              The surgical work area and instruments should be thoroughly cleaned and sanitized
              after surgery. All blood and tissue must be removed and instruments re-sterilized. Any
              animal carcasses should be disposed of properly.

        H.  Post Operative Recovery and Monitoring

              Rodents can often be stimulated to breathe, in the case of apnea, using gentle
              chest compression, gentle needle (25-30 ga.) insertion at the philtrum (space
              between the nose and mouth), or inflating the lungs with a rubber bulb (from a
              pipette) applied to their nostrils. An oxygen-rich environment also may be beneficial
              (place the rodent back onto the warm-water blanket and place it’s nose into the
              anesthetic mask, and adjust the oxygen flowrate to 0.5-1 l/minute). The drug
              Doxapram (DopramÒ) can be used to stimulate respiration, hasten arousal, and
              encourage the return of laryngopharyngeal reflexes when administered IV, IP, or
              injected sublingually, at a dose of 0.5-1.0 mg/100g (5-10 mg/kg). Doxapram may be
              repeated a total of three times at 5 minute intervals.

              Atipamezole (AntisedanÒ, dose 1-2.5 mg/kg, IP) or Yohimbine (0.5-2 mg/kg, IP) can
              be used to hasten the recovery of animals anesthetized with anesthetic
              combinations containing Xylazine, Medetomidine, or Dexmedetomidine. Reversal of
              xylazine's sedative properties with Atipamezole will also reverse its analgesic
              properties, allowing it to wear off slowly may be advantageous to managing post-
              operative pain, if the animal is stable.

              For animals weighing less than 500 grams, it is advisable to use a ceramic heat bulb
              (the use of heat lamps is discouraged), warming pad, or other external heat source
              beneath a portion of the housing cage for post-op recovery as the patient will
              typically experience some degree of hypothermia and lack of homeothermic
              abilities after prolonged anesthesia or major surgery. The animal should be able to
              choose the environment in which they are most comfortable - the warm area of the
              cage, or the cooler, non-heated section

              Animals must be monitored until they have recovered satisfactorily from anesthesia
              (i.e., normal respiration, body temperature in normal range, ambulatory, and able to
              eat and drink). The immediate post-operative period may range from 0.5-5 hours,
              depending on the analgesics and anesthetics used. This immediate, post-operative
              monitoring must be included in surgical planning.  Prior to replacement of the animal
              back into its’ housing room, the date and name of the surgical procedure should be
              noted on the animal's cage card.

              Depending upon the nature of the procedure and the condition of the animal, post-
              operative monitoring typically is required twice daily for three to five days

IV.  References

Academy of Surgical Research. Guidelines for Training in Surgical Research with Animals. J Invest Surg 2009;22(3):218-225.

Brown MJ, Pearson PT, Tomson FN. Guidelines for animal surgery in research and teaching.  Am J Vet Res 1993;54(9):1544-1559.

Fossum TW.  Small Animal Surgery. St. Louis, MO: Mosby, Inc.; 1997.