Advance preparations for surgery

The surgeon

Before carrying out any surgical procedure, it is important to familiarise yourself with the relevant anatomy of the surgical site and to practice the procedure on a dead animal. This will allow you to identify potential difficulties, will ensure you have all the correct instruments and material available, and also enable you to carry out the procedure more rapidly and with minimal trauma. This will reduce the likelihood of wound infections post-operatively, as well as resulting in better experimental outcomes. An understanding of the relevant anatomy will provide:

• An appreciation of the spatial relationship between structures – so you will be aware which structures underlie your surgical incision, and which precautions are needed to avoid damaging them.
• Knowledge of key structures that are present in the surgical field – so you can avoid inadvertent damage to blood vessels, nerves etc.
• An awareness of the tissue “planes” – which will enable careful blunt dissection to expose the area of surgery, and assist with restoring tissue layers when closing the surgical wound

You should also be knowledgeable in the relevant aspects of animal technology, surgery and anaesthesia. In the UK and EU legislation will require that you have been assessed as competent and have received adequate training to work with animals and to undertake the techniques in question. You will also need to have a Personal licence (PIL C) in the UK, and you should check that the procedures are authorised on the relevant Project licence.

If you are not familiar with the procedure, obtain advice from experienced colleagues. Ideally, observe the procedure being performed, and if possible act as an assistant to a more experienced colleague. This may mean travelling to another research institute, but the effort will be worthwhile as it will save time and improve outcomes when you commence carrying out the procedure.

Carrying out aseptic procedures almost always requires that you have an assistant, who can monitor the anaesthetised animal, open packs of sutures and instruments, and provide general assistance throughout.

The animal

Animals should be healthy and obtained from a reputable supplier. A period of acclimatisation for animals purchased from an outside source of at least 7 days is recommended. In this period of time animals are allowed to acclimatise to the surroundings and personnel. This allows the normal physiological stress responses associated with transport and changes of environment and husbandry routine to subside. This period will also allow personnel to become familiar with the behaviour and characteristics of the animal, facilitating assessment of the animal during its recovery from surgery; allow the animal to be monitored for any signs of ill health, and enable pre-operative assessment of food and water intake and body weight. Measurement of these parameters is of value when assessing an animal’s post-operative recovery (see also notes for Module EU20 and Module EU21).

Protocol for surgery and anaesthesia

A clear plan for surgery and anaesthesia including details of pre and post-operative care should be devised. In the UK this will be based on details in the project licence (which must be checked carefully) but the working protocol may need to be expanded in order to give a clear guide to all personnel involved of exactly what is planned. Surgery should be planned for a suitable time of day to ensure that sufficient staff and/or investigators are present to monitor and assess animals post-operatively whilst they recover. If surgery is undertaken late in the day, or just before a weekend/holiday period, it is likely to mean that there will be fewer opportunities for animal care staff to check on the animals whilst they are recovering or in the days following surgery.

Instruments/apparatus and accessories

There are many companies that manufacture surgical instruments. It is valuable to know what is available, (even if it is not possible to purchase the most suitable / most expensive items immediately). Many procedures are much easier to perform with appropriate instruments. Browsing through the catalogues of various companies can identify appropriate instruments for the procedure to be undertaken, however lack of specific instruments for use in rodent surgery may necessitate some lateral thinking and ingenuity.

Good quality instruments are certainly worth paying for, they last longer, make procedures easier to perform and cause less fatigue to the surgeon with extended use. If instruments are handled and cared for properly they will last for many years. Surgical instruments should only be used for surgical procedures to ensure they remain in good condition. Using surgical scissors for cutting paper, or to undertake post-mortems causes unnecessarily heavy wear and tear.

Further details of cleaning, preparing and sterilising instruments is given in later articles after an introduction to the principles of aseptic technique. The table below lists the instruments commonly used for rodent surgical procedures.