INTRODUCTION: REVIEW OF SCHEDULE 3 OF VETERINARY SURGEONS ACT 1966

The Veterinary Surgeons Act 1966 was created to prevent harm to animals by stopping anyone other than a qualified veterinary surgeon from performing any acts of surgery or medicine on an animal. Clearly, a blanket ban would make it difficult for owners to administer certain medications, or for farmers to carry out many husbandry procedures so certain amendments were made to the Act (Schedule 3 Amendments 2002), allowing laypersons to perform some procedures, e.g. removal of the hind dewclaws of puppies less than 1 week of age. Importantly, the Schedule 3 amendments also allow qualified (and registered) veterinary nurses to perform any medical treatment or any minor surgery not including entry into a body cavity. Student veterinary nurses are also allowed to perform such acts, provided certain criteria are met and they must be continuously, directly and personally monitored.

Unfortunately, there is no clear list of operations allowable under Schedule 3. The Royal College of Veterinary Surgeons (RCVS) stipulates that the vet must decide whether or not the technique is too complex, or likely to be too risky in a particular circumstance, and whether the nurse is competent to do the procedure. An important aspect of competence is the ability to recognize that something is beyond one’s capabilities, or that help is needed. When starting to perform any minor surgical procedure, the nurse should ensure that the vet is immediately available, should any unforeseen problems occur, and should be able to react appropriately to any predicament. For example, he/she should know what to do if cardiorespiratory arrest occurs, or if there is any haemorrhage. Registered veterinary nurses are now accountable for their actions so if the nurse is negligent there is a chance that he/she will be found liable by the RCVS. The directing veterinary surgeon may also be found liable, depending on the circumstances, so it follows that for both legal and animal welfare reasons, the practice team must make every effort to ensure that any surgical procedure is carried out to the best of that practice’s capabilities.

Finally, it is very important that the client has given fully informed consent for a procedure and is made fully aware of the fact that some or all of the procedure will be carried out by a nurse. This may involve a fair amount of prior client education: however, this should not be seen as a disincentive but an ongoing process that will enable veterinary nurses to achieve their full potential.

This chapter describes a few selected minor surgical procedures that should fall within the remit of Schedule 3 allowable operations. This is not an exhaustive list: rather a selection of the most common ones, or those that provide a good basic surgical example, which may be adapted to other clinical situations.

USE OF INSTRUMENTS

Scalpels, scissors, tissue forceps, haemostatic forceps and needle holders are the main instruments required for minor surgery. Their use is generally self-explanatory, but some tips may prove useful. Whatever method is followed for a particular technique, it is always important to follow some basic rules of surgery, to increase the likelihood of a successful outcome. Halstead’s seven principles of good surgical technique are outlined in Box 12.1. Close adherence to these is the key to successful surgery.

Several procedures refer to ‘palming’ an instrument, which is a useful technique when using looped instruments such as scissors, artery forceps and needle holders. These may be held by the third finger in the palm of the hand when not in use (Fig. 12.1). Palming an instrument allows the surgeon to use one instrument whilst holding one or more additional instruments in the same hand. The saved instrument may be swung into action when needed. This means that the instrument is readily available for use and no time is wasted trying to locate it.

Procedure: Handling a scalpel

1. Action: A blade should always be placed on (and removed from) a blade holder using needle holders.

    Rationale: This reduces the risk of cutting yourself. Artery forceps and other jawed instruments should not be used as the hard blade will damage the jaws.

2. Action: The pencil grip is generally used for handling a scalpel (Fig. 12.2).

    Rationale: This grip gives fine control over the blade.

3. Action: The scalpel blade should be drawn backwards along the tissue, using enough pressure to make a single clean cut through the skin.

    Rationale: A sawing motion will produce an untidy wound and is more likely to damage blood vessels, reducing the rate of healing.

4. Action: Your free hand may be used to steady the skin and to provide a little tension to the wound edges.

    Rationale: This moves the edges away from the scalpel and improves visibility. It also helps to reduce the incision effort and results in a neater wound.

Procedure: Handling needle holders

There are various types of needle holders:

• Gillies – has a scissor action for cutting suture ends but does not have a ratchet.

• Olsen-Hegar – has a cutting edge and a ratchet to hold the needle securely.

• Mayo-Hegar – similar to long-handled artery forceps and has a ratchet for holding the needle but no cutting edge.

• McPhail’s – has a spring ratchet so that squeezing the jaws together opens the holder and releases the needle.

In general, the easier ones to use are locking (ratcheted) needle holders without scissors. This is because the scissors may cut the suture material inadvertently.

1. Action: Mayo-Hegar needle holders should be held in the tripod manner (see Handling surgical scissors procedure).

    Rationale: This allows for precise placement of the needle and also allows palming of the needle holders.

2. Action: The needle is held about one-third of the way along its curve (Fig. 12.3) within the jaws of the needle holders.

    Rationale: Holding the needle too close to the suture end (‘swaged on’ area) will result in bending of the needle as it is weak at this point.

3. Action: The wrist is used to rotate the needle, pushing it through the tissue in a curve.

    Rationale: It is easier and less traumatic to allow the needle to follow its own curve through tissue.

Procedure: Handling surgical scissors

1. Action: The tripod hold is most commonly used for scissors (Fig. 12.4).

    Rationale: The tripod hold allows a more precise placement of the scissors and provides a strong shearing force. It also allows the scissors to be palmed if desired.

2. Action: The tips of the thumb and third finger are placed in the scissors loops, and the index finger is used to direct the tip of the scissors.

    Rationale: The second finger helps to steady the scissors.

3. Action: For cutting fine tissue, use the tips of the scissors; for cutting thicker tissues, the base of the scissors may be better.

    Rationale: The shearing forces are greater at the base of the scissors but there is greater control at the tip, ensuring a more precise cut.

4. Action: Blunt dissection involves inserting the tip of the closed scissors into tissue and opening them whilst they are inserted.

    Rationale: Blunt dissection reduces the risk of inadvertently cutting through blood vessels or nerves. Fine scissors such as Metzenbaums are more suitable for this technique.

5. Action: Scalpel blades should be used to cut skin and scissors used to cut subcutaneous tissue.

    Rationale: The shearing action of scissors crushes minute blood vessels in the skin and can delay healing or increase scar formation.

6. Action: Surgical scissors should not be used to cut suture material.

    Rationale: This will blunt the scissors. Suture scissors should always be used for this purpose.

SURGICAL PROCEDURES

Procedure: Surgical treatment of abscesses

1. Action: Assess the patient for dehydration and commence intravenous fluids if required.

    Rationale: Animals with abscesses are typically pyretic and may not have eaten or drunk for several days.

2. Action: Administer a premedication (premed) to the patient as directed by the veterinary surgeon.

    Rationale: A premed will contain an analgesic and will also reduce the total amount of anaesthetic agent required.

3. Action: Stabilize the patient under sedation or general anaesthetic.

    Rationale: This will reduce any pain and prevent unwanted movement from the patient.

4. Action: Clip the skin surrounding the abscess and prep for aseptic surgery (see Chapter 7).

    Rationale: This reduces the risk of introducing new bacteria into the abscess. It also makes it easier to keep the wound clean during the healing process.

5. Action: Drape the surgical site (see Chapter 7).

    Rationale: This reduces the risk of new bacteria getting into the wound. Waterproof drapes prevent the patient becoming wet when the abscess is flushed.

6. Action: Observe strict aseptic technique: wear gloves, gown and mask.

    Rationale: This will reduce the risk of introducing new bacteria into the wound, such as meticillin-resistant Staphylococcus aureus (MRSA) and will protect you from acquiring infection from the patient.

7. Action: Make a stab incision into the abscess, preferably at the most dependent area. A no. 11 scalpel blade is most useful for this.

    Rationale: Making the opening at the most dependent part will help gravity to drain the abscess.

8. Action: Ensure exudate is emerging from the incision. If none is seen, try going a little deeper with the blade, ensuring that no damage is done to the deeper tissues.

    Rationale: If none is seen, it may be that the incision is not deep enough.

9. Action: Using the blade, make an X-shaped incision about 1 cm in size. Alternatively, a small triangle of skin may be cut out.

    Rationale: A stab incision may heal too quickly to allow adequate drainage.

10. Action: Gently squeeze the area surrounding the incision to release the purulent material.

    Rationale: The pus may be quite viscous and require encouragement to leave the wound.

11. Action: Using a 20 ml syringe, three-way tap, 19G needle and giving set, flush the wound with at least 500 ml of warmed sterile saline (Fig. 12.5A, B). If any necrotic tissue remains, scrape the cavity with a sterile Volkmann curette or a no. 10 scalpel blade

    Rationale: Flushing the wound removes much of the bacteria and necrotic tissue. Scraping will remove further necrotic material which, if left, could delay the healing process.

12. Action: The wound is left open to drain.

    Rationale: Suturing the wound may result in wound breakdown, as bacterial infection will still be present within the abscess cavity.

13. Action: Antibiotics and suitable analgesics are prescribed for an appropriate length of course.

    Rationale: To kill off any infection and to prevent recurrence.

14. Action: The owner may be instructed to bathe the wound in salty water for a few days.

    Rationale: The combination of bathing and the use of antibiotics should result in healing of the wound within 7–10 days.

SKIN BIOPSY TECHNIQUES

Biopsies are samples of tissue that may help us to gain insight into a particular disease process. Biopsying may be carried out to investigate a skin disease (dermatopathy) or an abnormal mass and the results may provide valuable information as to the presence of a disease and an indication of what the treatment should be. A biopsy procedure should ideally give maximum information for minimal patient morbidity. When neoplasia is suspected, it is preferable to perform a biopsy prior to considering surgery in order to assess whether it is possible to remove just the mass (local excision) or whether a large area of normal tissue surrounding the growth must be removed to ensure that any stray neoplastic cells are also removed (wide margin of excision). Table 12.1 lists common skin and subcutaneous tumours of the cat and dog.

The main types of biopsy are:

Procedure: Surgical biopsy

1. Action: Administer a premed to the patient as directed by the veterinary surgeon.

    Rationale: A premed will contain an analgesic and will also reduce the total amount of anaesthetic agent required.

2. Action: Stabilize the patient under sedation or general anaesthetic.

    Rationale: This will reduce any pain and prevent unwanted movement from the patient.

3. Action: Clip the skin surrounding the biopsy area and prep for aseptic surgery (see Chapter 7).

    Rationale: This reduces infection and wound-healing complications. Note that in some skin investigations this step is missed out as it can destroy subtle pathological changes.

4. Action: Drape the surgical site.

    Rationale: This reduces contamination of the wound.

5. Action: Observe strict aseptic technique: wear gloves, gown and mask.

    Rationale: This reduces contamination of the wound.

6. Action: Using a no. 10 or 15 scalpel blade on a holder, make an elliptical incision through the skin at one edge of the biopsy site, aiming to remove a piece of tissue of about 1 × 0.5 cm.

    Rationale: This allows the wound to be closed more easily than a circular incision. The edge of a mass affords the best biopsy as the central area may have tissue necrosis which will obscure the diagnosis.

7. Action: The biopsy should include all skin layers and should include some normal tissue at the edge.

    Rationale: This will allow the pathologist to examine the normal tissue for evidence of invasion, which is one sign of malignancy.

8. Action: Close the skin wound using simple interrupted sutures of non-absorbable suture material, e.g. Ethilon.

    Rationale: Absorbable sutures may not absorb well in abnormal tissue.

9. Action: Place the biopsy in a 10% solution of formol saline.

    Rationale: This fixes the tissue and delays decomposition, preserving the histological features.

10. Action: Seal the biopsy container appropriately and label it with the patient’s details.

    Rationale: Control of Substances Hazardous to Health regulations apply to all biological samples.

11. Action: Send the sample to the pathology laboratory with a completed histopathology request form which includes the following information:

• The patient’s details

• A brief description of the appearance and position of the biopsied tissue

• How long it has been present

• Any previous or concurrent treatment

• Whether margins have been included in the biopsy.

    Rationale: The pathologist will be able to take all this information into consideration when considering the prognosis.

12. Action: The patient should be discharged, with instructions to the owner on wound care and when to expect the biopsy results.

    Rationale: Antibiotics are generally not required following a biopsy.

Procedure: Punch biopsy

1. Action: Follow steps 1–5 as above.

    Rationale: This is a surgical biopsy and so will require the same aseptic technique.

2. Action: Select a sterile biopsy punch of suitable size and place it perpendicular to the skin surface over the area to be biopsied.

    Rationale: A larger punch will give a better chance of a useful biopsy.

3. Action: Using slight downward pressure, rotate the punch backwards and forwards, cutting through the skin as evenly as possible (Fig. 12.6A).

    Rationale: Ensure that the punch has gone all the way through the skin and has not damaged underlying tissue, i.e. muscles, nerves or blood vessels.

4. Action: Lift the punch away from the skin at a slight angle: this should remove the circle of tissue. If the tissue remains in situ, use a hypodermic needle to lift one edge and then cut the attachments with scissors (Fig. 12.6B).

    Rationale: Using forceps to lift the tissue may damage the biopsy.

5. Action: Follow steps 7–12 as above.

    Rationale: The product of this procedure is dealt with in exactly the same way.

Procedure: Tissue core biopsy

This technique is more useful for evaluation of subcutaneous masses than skin masses.

1. Action: Follow steps 1–5 as for a surgical biopsy.

    Rationale: Although there is a smaller wound than in a surgical biopsy, there is still potential for contamination and infection.

2. Action: Prime the trigger tissue core biopsy device by drawing back the spring-loaded clip.

    Rationale: This must be done before the needle is inserted into the tissue.

3. Action: Make a small cut over the chosen point of entry of the biopsy needle with a no. 11 scalpel blade.

    Rationale: The needle tends to blunt easily so cutting the skin removes one layer of tissue through which the needle must pass. This also allows more control over placement into a subcutaneous mass.

4. Action: Introduce the needle into the mass and depress the plunger to its first point of tension.

    Rationale: This advances the needle into the centre of the mass and exposes the biopsy channel.

5. Action: Fully depress the plunger until a click is felt.

    Rationale: The outer sheath is sprung forward, effectively cutting a core of tissue from the mass.

6. Action: Remove the needle and pull the plunger out again, reloading the device.

    Rationale: Pressing the plunger to its first tension at this stage exposes the core biopsy within the channel.

7. Action: Fill a 5 ml syringe with sterile saline and attach a 23G needle. Use this to rinse the biopsy off the needle and into a biopsy pot containing 10% formol saline (Fig. 12.7).

    Rationale: Using a needle to scrape the tissue off may damage the delicate biopsy.

8. Action: Repeat the process if further biopsies are required.

    Rationale: A new needle must be used if other masses are to be sampled to prevent the risk of spread of other malignant cells.

9. Action: Examine the biopsy site for any evidence of bleeding.

    Rationale: If there is bleeding, apply hand pressure over the site for 5 minutes; this should be sufficient to stop the haemorrhage.

10. Action: Follow steps 10–12 as above.

    Rationale: The product of this procedure is dealt with in exactly the same way.

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