Minor Surgery
Minor surgery is any invasive operative procedure in which only skin or mucus membranes and connective tissue is resected e.g. vascular cutdown for catheter placement, implanting pumps in subcutaneous tissue. Procedures in which the surgical field cannot be effectively disinfected, e.g. tooth extractions and gingival grafts, will generally be considered minor. This category also includes biopsy, an invasive operative procedure for procurement of tissue samples or body fluids using a needle or trocar. Minor surgical procedures may be done in a laboratory setting using appropriate aseptic technique, including a clean work area, preparation and disinfection of the surgical site including clipping of the hair and surgical scrub of the skin, draping of the surgical site with sterile drapes, mask by the surgeon and any assistants working in the surgical field.
Major Surgery
Major surgery is any invasive operative procedure in which a more extensive resection is performed, e.g. a body cavity is entered, organs are removed, or normal anatomy is altered. In general, if a mesenchymal barrier is opened (pleural cavity, peritoneum, meninges), the surgery is considered major. For surgical procedures that do not clearly fall in the above categories, the chance for significant inadvertent microbial contamination is to be a primary consideration. Generally, the classification of major will be applied only to procedures in which the animal is anticipated to survive longer than 24 hours. If the animal is to be terminated in less than 24 hours, techniques applicable to minor surgical procedures may be used. A procedure previously classified as minor will be changed to major if microbial contamination proves to be a significant problem. In general, the standards for major surgery apply only to non-rodent species. However, if microbial contamination proves to be a significant problem with procedures carried out in rodents, the standards for non-rodent species must be applied. All major surgical procedures in non-rodent species must use appropriate surgical techniques and must be conducted in facilities intended for survival surgery and used only for that purpose. The facilities must be designed and managed to insure a level of sanitation appropriate for aseptic surgery. The operating room should contain only the equipment and supplies required to support the procedure being performed. A separate area, apart from the surgery room, must be provided for preparing the animal for surgery although the final surgical preparation, not to include clipping of hair, may be conducted in the surgery. An area equipped with surgical scrub sinks should be apart from the operating room. A surgical-support area should be provided for storing instruments and sterile supplies and for washing and sterilizing instruments.