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Conducting Surgery

Location for surgery

The surgical area should be uncluttered and easily disinfected. The area should be dedicated to surgery during the procedure but may be used for other purposes when not being used for surgery. Patient preparation (fur removal) and recovery should take place in a location removed from the surgical area.

Surgical attire and surgeon preparation

Rodent survival surgery must be performed using sterile gloves, a clean lab coat or gown and a facemask. The surgeon should either wash their hands with an antimicrobial soap or use an alcohol-based hand disinfectant (cover all surfaces of the hands with the disinfectant and rub until the hands feel dry) prior to putting on sterile gloves. If using alcohol-based hand disinfectant, prewash hands if soiled with organic material (such as blood or urine). A head covering is recommended to reduce the risk of stray hair falling into the operative field.

Opening the surgical pack

Place the sterile surgical pack in a convenient location near the animal. The pack should be placed so as to minimize the amount of unsterile space between the pack and the draped animal. If the surgeon must open the pack, he(she) must open it prior to putting on sterile gloves. Otherwise, a (non-sterile) assistant can open the pack for the surgeon. Sterile suture or other sterile material may be opened and gently dropped onto the open pack area.

Draping the surgical site

The skin and hair surrounding the (prepared) surgical site should be covered with a sterile surgical drape. The drape effectively enlarges the sterile area around the surgical site and reduces the chance of contamination. The drape material must be placed on the animal after the surgeon has donned sterile gloves. Additional drape material may be included within the sterile pack and used to set instruments on during surgery.

Maintaining sterility

Surgeons and support staff must work together to maintain sterility during the surgical procedure. Sterile articles must touch only sterile surfaces and all sterile surfaces should be kept as dry as possible. If contamination of surgical gloves or equipment is suspected, new sterile gloves or equipment should be substituted for the contaminated material.

It is strongly recommended that a non-sterile assistant be available during the procedure. It is extremely difficult for even experienced surgeons to maintain sterility during sugery when working alone, especially if performing sugery on multiple animals.

Place sterile instruments on a sterile surface when not in use.

Do not touch non-sterile surfaces when wearing sterile gloves.

Instrument Tip Technique for Certain Rodent Surgical Procedures

Although challenging, instrument tip technique may be useful for specific rodent surgery situations. Generally this is limited to surgeries in which incisions involve only the skin and manipulation of internal organs does not occur. Keep the following points in mind when using “tips only” technique:

  • The animal must be maintained in a surgical plane of anesthesia throughout the procedure.
  • Begin surgery with sterile instruments and handle them aseptically throughout the procedures.
  • The same set of pre-sterilized instruments may be used for up to five similar surgeries provided aseptic technique is followed throughout all procedures. *See the guidelines that follow for information on using a glass bead sterilizer in multiple rodent surgeries.

Sterile surgical gloves do not have to be worn if the following criteria are strictly adhered to:

  • Gloves are changes after completing the surgical scrub such that new clean gloves donned at the beginning of the surgical procedure.
  • The gloved hands never touch the working (tip) end of the instruments, the suture, suture needle or any part of the prepped surgical field.
  • Only the sterile tips of the instruments are used to handle the animal’s tissues, suture needles, suture material, wound clips or other sterile material.

Outline of procedures in “tips only” surgery

  • The surgeon must wear a mask, and clean lab coat or gown. A head covering (cap or bonnet) is recommended.
  • Place the anesthetized and surgically prepped animal on a warming device that has been covered with a clean paper bench towel.
  • Open your sterile surgical pack and any other sterile equipment needed (e.g., suture material) without touching or handling the sterile contents.
  • Wash your hands with soap and water or apply alcohol-based hand disinfectant. After hands are dry, put on clean examination gloves.
  • If a surgical drape is used, the surgeon must handle the sterile drape only by its edges so that it does not become contaminated. (The drape should contain a ‘pre-cut’ opening that allows access to the surgical site as it will be difficult for the surgeon to cut an opening without contaminating the drape.)
  • Once the instruments are picked up by the surgeon, only the tip of the instrument is considered to be sterile. If the surgeon lays the instrument down, the sterile tip must be placed on a sterile gauze sponge or drape. The instrument handle should not come in contact with the sterile surface to avoid contamination of that surface.
  • If the tip of a surgical instrument becomes contaminated, the tips may be re-sterilized by wiping away blood or tissue using a moistened gauze or alcohol pad and placing the tips in a hot bead sterilizer.
  • Keep in mind that the surgeon cannot touch the instrument tips, suture material or wound clips, suture needle or any part of the prepped surgical field with his/her hands during the surgery.
  • Gloves should be rinsed with 70% alcohol between surgeries. If you must handle another mouse to anesthetize and prep it, you must change gloves before performing the next surgery.

While performing surgery, be careful not to get paper or cloth instrument drapes wet. Wet material acts as a wick to pull bacteria through from the non-sterile surface below. When this occurs the instruments should be considered contaminated and re-sterilized before further use.

*Using a Glass Bead Sterilizer in “Batch” or Instrument Tip Rodent Surgeries

If surgeries will be performed on a group of animals, a glass bead sterilizer can be used to sterilize the tips of the instruments between animals. Up to five surgical procedures may be done with one surgical pack. After that, a new sterile pack must be used.
A glass bead sterilizer will sterilize only the tips of surgical instruments. If using a glass bead sterilizer you should remember the following: 

  • Tissue, blood and other debris must be removed from the instruments before placement in the sterilizer.
  • The tips of the instruments become extremely hot.
  • The instruments must be allowed to cool before applying them to the skin or other tissues.
  • The tips of delicate instruments may become damaged during immersion in the glass beads.

The beads must be pre-heated to the recommended temperature and the instruments exposed for the recommended time (see user instructions for the sterilizer you are using).

After removal from the sterilizer, place the tips of the instruments on a sterile surface. To avoid contamination of the tips of the instruments during the surgical procedure, always keep the tips on a sterile surface and pointed in the same direction.

Wound Closure and Suturing

Incisions through multiple tissue layers must be closed separately. Poor wound closure technique will result in delayed healing and increased incidence of post-operative infection, as well as animal discomfort and pain. Incisions in tissues underneath the skin (e.g., muscle, subcutaneous tissue) are typically closed using absorbable suture material. Proper suture technique requires practice. Surgical knots must be tied using the correct method and sutures not tied too tightly. Tight sutures inflame the tissues and may cause the animal discomfort. Consult with a veterinarian for advice on wound closure and suture material selection.

Rodent skin incisions are typically closed with stainless steel wound clips. These clips must be sterile and applied aseptically. The clips must be observed daily post-operatively and can usually be removed in 7-10 days if the wound is healed. Wound clips must not be left in the skin beyond 14 days post-operatively.


Hoogstraten-Miller, S. L., & Brown, P. A. (2008). TECHNIQUES IN ASEPTIC RODENT SURGERY. Current Protocols in Immunology / Edited by John E. Coligan ... [et Al.]CHAPTER, Unit–1.12–14.


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