Purpose
The purpose of this policy is to define IACUC expectations for post-operative monitoring as well as standardize and outline expectations for proper surgical or wound closure and ensure the best possible outcome for successful healing.
Background
Animals should be monitored post-operatively for incisional healing, signs of pain, infection, as well as general indicators of recovery such as activity level, attitude, food and water intake, and urination and defecation. Some components of the monitoring plan such as evaluation of incisional healing will be similar across species, while others will vary depending on the species. For example, temperature, heart rate or pulse, and respiratory rate (TPR) are more practical to evaluate in some larger animals. The veterinary staff should be consulted when developing a post-operative monitoring plan to ensure that it is appropriate for the species and procedure.
Sutures, tissue adhesive, wound clips, and staples are frequently used for the closure of surgical incisions and other skin wounds in laboratory animals. The appropriate type of surgical closure material to be used should be determined in consultation with veterinary staff. Incisions closed by these techniques or devices require frequent observation until the healing process is reasonably complete and, with the exception of tissue adhesive, must be removed in a timely fashion in order to prevent unnecessary irritation, pain, and possibly infection.
Policy
Post-operative monitoring:
IACUC protocols must specify the post-operative monitoring plan, including the frequency, duration and what will be monitored. These parameters should be determined in consultation with the veterinary staff.
The following provides broad guidelines for the minimum frequency and duration. Note that these may be increased by the veterinarian depending on the complexity and severity of the surgery.
For non-rodent mammals, once to twice daily monitoring is expected for the first three to five days post-operatively, and then daily monitoring until the incision has healed (at least 7-10 days total for major surgery).
In the case of rodents and non-mammalian vertebrates, daily monitoring for at least the first three days, and then at least 3 times a week monitoring until the incision has healed.
For rodent surgeries with a potentially higher incidence of complications (for example, intra-abdominal surgeries with midline incisions), daily post-operative monitoring for the first 7-10 days is expected.
Inform veterinary services of concerns or signs of illness such as lethargy, fever, dehiscence, infection, or missing sutures or staples. Regarding dehiscence, the veterinary staff must evaluate whether it is clinically appropriate for the dehiscence to be repaired, and if so, the method of repair, unless the IACUC protocol has dehiscence repair surgeries described.
Records of post-operative monitoring must be maintained and readily available to veterinary staff.
Surgical and Wound Closures:
Background
Surgical closures that require consultation with a veterinarian include incisions where there are large muscle defects, those that require significant tissue debridement, contaminated wounds, and closures with significant skin deficits (e.g. large cranial explants). If a surgeon encounters an obstacle outside of or beyond the knowledge or area of expertise, they must page a veterinarian for assistance.
Planned incisions should be made with the intention to preserve integrity of as many underlying nerves, blood vessels, and muscles as possible. Tissues should be handled gently with appropriate instruments, as little as possible, and kept moist with warm saline to prevent tissues from drying out.
Wound closures should be performed by a veterinarian or under the guidance of a veterinarian. Severely damaged or dead tissue and foreign bodies must be removed, and any signs of pre-existing infection should be addressed and treated. Wound edges should be debrided of all devitalized tissue prior to apposition. Tissues ready for primary closure should be free of thickened or discolored areas and have evidence of good blood supply (active bleeding from edges). Surgeons must maintain a sterile and aseptic technique during wound closure.
Suture materials
Suture type and needle type must be appropriate for each type of tissue to maximize healing and minimize infection. The smallest suture with sufficient strength should be used. Silk sutures and braided sutures should not be placed in the skin of animals. Absorbable sutures are not recommended for use in the skin of non-primate animals, and any proposed use should be described and justified in the IACUC protocol. Absorbable sutures may be used for intradermal closure. When appropriate, tissue adhesive, wound clips and staples may be used for skin closure.
Suturing technique
Analgesics including local blocks should be administered as described in the protocol. Suture pattern and spacing of sutures must be selected and appropriate for each type of closure. Multi-layer closures should be performed whenever possible to ensure elimination of subcutaneous dead space. Dead space in the wound from fluid or air will impede healing and can invite infection. Skin edges must meet directly for a proper closure. Proper tension should be used when closing incisions, so that wound edges are apposed fully covering underlying tissues, but loose enough to prevent ischemia and tissue necrosis.
After surgery, any blood, debris, and leftover surgical scrub should be gently cleaned from the surrounding tissue and/or hair/fur.
Suture removal
The tissue must be held in apposition until the healing process provides the wound with sufficient strength to withstand stress. The duration of time before suture removal will vary with each area and will be outlined in the protocol or determined by the veterinarian. In rodents, suture removal is generally done 10-14 days post surgery.
During the healing process, all attempts should be made to keep the area dry. Creams, ointments, or disinfectants should not be used unless the veterinarian prescribes such treatment.
Approval/Review Dates
Originally Approved: 11/19/1998
Last Reviewed/Revised by the IACUC: 07/15/2021