Rodent Survival Surgery

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Rodent Survival Surgery

• University of South Florida
• Margi Baldwin
  May 2006

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Batch Surgery

• Rodents are typically done in larger numbers or
  batches of animals to provide the statistical
  n needed for a given model.
• Often, these numbers preclude the ability to
  provide separate instrument packs for each
  animal.
• Rodents undergoing survival surgery are treated
  the same way as any other larger species in that
  the rules of asepsis apply.

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Considerations of batching

• Shared instruments and supplies are common when
  performing batch surgeries.
• However - - -
• Asepsis must be maintained throughout the
  procedure.
• Asepsis must be regained between animals.
• Anesthetic induction, recovery and monitoring
  methods of rodents is as important as with other
  species!

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Preparation of the Instruments

• ALL instruments must be sterilized prior to use.
• The following are acceptable methods
• Steam must follow manufactures recommendations
  regarding time/temp/pressure.
• Chemical must follow manufactures
  recommendations regarding solution concentration,
  contact time and rinsing of agent.
• Gas must follow manufactures directions
  regarding exposure time and pack contents.

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Plan It Out

• Arrange your instruments in a tray, dish or bowl
  to protect them and provide yourself a safe
  storage area for them between surgeries.
• Provide two bowls of some sort one for sterile
  water and one for sterile saline or
  PBS/instrument storage.
• Identify disposable supplies you will place in
  the pack, if any (gauze, drapes, cotton tipped
  applicators, etc. Note - Gas sterilization can
  preclude inclusion of absorbable materials)
• Identify project-specific consumables you will
  place in the pack
• Appliances, catheters, needles, syringes, screws,
  etc.

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How Many Surgeries Per Pack?

• This will vary depending on project and
  surgeons skill. General guidelines -
• Is it major or minor surgery? Minor surgeries
  allow for more animals per pack.
• Is the procedure long? Longer surgeries mean
  increased exposure of the tissues, which can lead
  to higher risk. Therefore, less animals are done
  per pack.
• Is the surgeon skilled or novice? More experience
  supports better tissue handling skills and faster
  open-to- close times, allowing an experienced
  surgeon to perform more surgeries per pack.

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Ways to Minimize Contamination Between Animals

• Wipe down all surrounding surfaces and associated
  equipment with Clidox, Sporicidin, or other
  approved sanitizer.
• Counters, hood surfaces, lights, bead
  sterilizers, anesthesia machine.
• Keep airflow and traffic to a minimum around the
  surgical station.
• Designate drop zones for dirty/used items

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Setting the Stage

• It is important to set up the surgical station
  prior to beginning any manipulations of an
  animal.
• Open the packs outer layer (all packs should be
  double wrapped).
• Open any needed sterile items (e.g., suture,
  needles, syringes) not in the pack and drop by
  the pack/inside the sterile field.
• Don sterile gloves and peel back the inside
  layer, picking up and arranging newly opened
  sterile items.
• Empty bowls of contents and place face up.
• Arrange equipment, supplies and instruments in a
  manner that facilitates aseptic technique.

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Setting the Stage

• Pour sterile water into one of the bowls and
  sterile saline or PBS into the other.
• Sterile water is used PRIOR to placing
  instruments in the bead sterilizer. Water is
  able to lyse blood cells and aids in removal of
  fat.
• Sterile saline is used to cool/rinse the
  instruments AFTER bead sterilization. The bowl
  is used to store instruments until needed for
  the next animal.
• Kept submersed, instruments are less susceptible
  to contamination by airborne particulates, and
  are less likely to be pushed into a non-sterile
  area or accidentally dropped.

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Second pack layer removed

• Note the use of blue chux pad as inner layer to
  absorb fluids.
• One tray holds disposables such as gauze,
  cotton tipped applicator sticks.
• One tray holds the instruments.

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Set up w/placemats

• Note use of pre-fenestrated drapes and overall
  arrangement of the field.
• Placemats are removed with each animal so that
  contaminants and loose fur are also removed
  between animals.
• Note the use of paper towels as place mats.

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Set-up showing bowls bead unit

• Drapes, gauze, cotton tipped applicators and any
  other disposable placed to top of field.
• Instruments held in saline filled tray, sterile
  water bowl also present both in close proximity
  to the bead sterilizing unit.

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Instruments in bead sterilizer

• Instruments of like size and function are placed
  in the bead sterilizer together.
• No more than 3-4 instruments should be in bead
  sterilizer at any one time.
• Instrument contact-time in bead sterilizer is 15
  seconds.

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Set up w/microscope

• Scope is carefully positioned prior to opening
  the sterile pack beneath.
• Lights are positioned and turned on to provide
  prep person with a target to place the animal
  within.
• Sterile gauze is used to reposition lights and
  adjust focus on the scope once the surgeon dons
  sterile gloves.
• Wipe down the scope/light w/sanitizer first!

15
Mobile prep station

• Set up a mobile prep station to service
  multiple surgeons, or when only one gas facemask
  is available.
• Mayo stand used here. Note scrub soap,
• alcohol wipe,
• betadine paint.

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Surgical Scrub

• Area is clipped well beyond intended incision
  site.
• Rodents require a minimum of two surgical scrubs,
  using a germicidal soap, followed by iodine
  paint.
• Start in the center and spiral outwards.

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Positioning for draping

• Following two scrubs and betadine paint, move
  animal to surgical table.
• Position animal, as appropriate, for surgical
  approach and procedure.
• Take care not to touch area that has been
  surgically prepped.

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Positioning the Animal

• The surgical light is used to hold tape for
  positioning animal on the surgical field (after
  completion of initial clip and scrub in prep
  area).
• Final iodine paint is applied by surgeon AFTER
  donning sterile gloves.

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Animal is positioned PRIOR to donning sterile
gloves.

• Position and secure gas nose-cone, or intubation
  tube (if intubated).
• Position the light source.
• The surgeon then dons sterile gloves for draping
  the animal.

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Mouse prepped/positioned
Final drape
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Mouse draped and in position within surgical field
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Draped/prepped incision site
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Recovery of rodents

• Recovery of rodents is the same as other species.
  They need supportive care.
• Warmed cage/bedding
• Heat source controlled or ambient (e.g., one that
  cannot continue to heat beyond body temperature
  or one that will cool naturally).
• Fluid therapy
• Analgesics
• Help with accessing food water post operatively
  (food may be placed on cage bottom, or
  supplemented with high calorie soft foods).

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Mouse, post-op, with warm water-filled glove

• Once sternal and capable of purposeful movement,
  the animal is returned to its home cage.
• Heat source (glove) should be removed prior to
  returning an animal to its holding room.

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Post-op mouse w/food on cage bottom
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Thanks to the researchers who so graciously let
us photograph their models!!

• Margi Baldwin, RVT, LATG, SRS, MS
• Training Coordinator USF
• Division of Comparative Medicine