Laparoscopy

Introductory theory

Section 1 of 7

Advantages

• Reduced post operative pain
• Quicker post operative recovery
• Reduced risk of wound breakdown
• Reduced post-operative hospitalisation requirements
• Magnified visualisation of surgical field
• Smaller wounds
• Reduced tissue trauma and inflammation
• More accurate haemostasis
• Positive client perception

Potential disadvantages

• Cost of equipment
• Surgeon and team training required
• Lack of tactile feedback
• Not suited to all patients/procedures
• Risk of laparoscopic specific injuries
• Occasional need to convert to open surgery
• High cost of consumables

Section 2 of 7

The main benefit

A common misconception is that the main benefit of laparoscopic surgery is the small wounds. In fact, the most significant benefit is enhanced visualisation (aided by magnification by the endoscope) which leads to safer surgery. The ultimate aim of laparoscopy (and thoracoscopy) should be safe, visual surgery with the added benefit of small wounds. This is opposed to small open abdominal surgery incisions, which lead to poor visualisation and unsafe surgery.

VAS – Video Assisted Surgery refers to using the endoscope to gain greater visualisation, but still performing open surgery e.g. tissue extraction for a lung or liver lobectomy, small intestinal full thickness biopsies.

Section 3 of 7

What is possible? What is sensible?

  • Always consider if a laparoscopic approach does offer benefit to the patient.
  • It is recognised in human surgery that some procedures have better surgical outcomes with the traditional open abdominal approach (e.g. prostatectomy).
  • Laparoscopic assisted surgery may provide a quicker, simpler and less expensive option e.g. for cryptorchid castration, full thickness intestinal biopsies.

Section 4 of 7

Electrosurgery

Electrocautery

Direct Current (DC) provides a heated wire, the current does not pass through the patient’s body.

Electrosurgery

High voltage and current is passed through a patients tissues to achieve clinical effect at the top of the electrosurgical instrument.

  • Monopolar surgery – a patient return electrode is on the patient, the active electrode is at the tip of the instrument. Devices can be used in cutting more for fine dissection, or coagulation mode for larger areas of tissue. A major risk with monopolar surgery is burns to the patient if the patient return electrode is not in proper contact with the body.
  • Bipolar surgery – there is no need for a patient return electrode, controlled tissue desiccation can be achieved with limited risk to surrounding tissues.
  • Tissue feedback controlled bipolar surgery (Ligasure, Enseal) – seal blood vessels up to 7mm, providing an audible signal when the tissue has been sealed. Most have an inbuilt blade to the cut the tissue.
  • Ultrasonic scalpel (Harmonic scalpel) – differs from electrosurgery as an ultrasound transducer in the handpiece transmits high speed vibrations to the tip, enabling vessel coagulation without the risks associated with heat generation in electrosurgery. Currently these are single use only handpieces.
It is essential to examine the abdomen at the start of any laparoscopic procedure. This is for the detection of inadvertent trauma during access, but also for detection of clinically silent pathology e.g. liver tumours.

Do not perform laparoscopic or thoracoscopic procedures unless already competent with standard open abdominal or thoracic procedures. Conversion to open techniques may be required in some circumstances.

Section 5 of 7

Equipment

Camera System

Includes the telescope, camera, processor, light source and light cable. This is not an area to compromise on by purchasing cheaper equipment, good visualisation is vital in laparoscopic surgery.

Inexpensive USB cameras are offered for veterinary surgery, but these have a lag period to the image displayed on the screen and are not suitable for laparoscopic surgery.

The most common component to fail and cause a sudden deterioration in image quality is the light cable. It is made of bundles of glass fibres which are intolerant of being dropped or bent.

Telescopes are primarily available in 0˚ and 30˚ angles of varying diameters. 5mm diameter is most commonly used in veterinary cases, but 3mm scopes are advantageous in smaller animals enabling a wider visual field in small spaces.

Instruments

There is a huge variety available depending on the procedures being performed, the most commonly used in veterinary surgery are 5mm diameter 30cm long instruments.

Disposable ports are available, but they are not cost effective. Good quality reusable ports and instruments are reliable if well cared for.

Soft, flexible ports without valves are best for thoracoscopic surgery, as rigid metal ports can cause rib fractures when levering instruments.

Retractors are available for more complex laparoscopic procedures e.g. adrenalectomy.

Staplers are very expensive for veterinary medicine, but can be used for gastrointestinal and lung surgery.

Haemostatic clip applicators are also available, some of which are reusable.

Abdominal Entry

Safe access may be the most challenging, and riskiest, part of laparoscopic surgery. Injuries to underlying structures are always a risk whatever method is used. The options available are:

  1. Veress needle blind approach – this has fallen out of favour in human surgery due to the risk of major vascular trauma. The main risk in veterinary patients is to the spleen, which is less likely to be life threatening if damaged.
  2. Open access – regarded as the safest method, strongly recommended if the patient has had previous surgery due to the risk of adhesion of viscera to the abdominal wall. An incision is made in the skin, and a combination of blunt and sharp dissection used to gain access to the abdomen. The port is then placed through the small incision.
  3. Optical controlled access – a Ternamian tip steel port can be screwed through muscle layers (after making a skin incision) whilst visualising with the endoscope held within the port. Optical trocars are also available, which have a blade to cut as the port is inserted under visualisation.
Insufflation

This is achieved with CO2, one should aim for 8-10mmHg pressure and not exceed 12mmHg due to the potential risk of impairment of blood flow to abdominal organs (namely the kidneys) and impaired movement of the diaphragm. The initial flow rate should be set at 1 to 2L/min, higher flow rates can be used to compensate for leakage later on in the procedure if required.

Extracorporeal Suturing

A useful technique to master, in which a knot is tied out with the abdomen and tightened using a knot pusher. Commercial loops are available (Endoloop), but it is more economical and very straight forward to prepare one’s own using the Meltzer Knot technique.

Section 6 of 7

Specific risks of laparoscopic surgery

Access injuries – to the spleen, liver, bowel or major vasculature caused by entry of the Veress needle or initial port/trocar.

Electrosurgery injuries – ‘out of site’ injuries by instruments not in view of the endoscope. The cauterising instruments can cause thermal damage to abdominal viscera, most concerning of which is bowel injury. Due to the minimally invasive nature of laparoscopic surgery, much less inflammatory response is stimulated within the abdomen. This means that the onset of signs of peritonitis from a bowel perforation is delayed and signs can be subtle initially.

Section 7 of 7

Further Resources

Clinical Manual of Small Animal Endoscopy (2012)

Hotston Moore, Ragni, Wiley-Blackwell

Chapters on arthroscopy, laparoscopy, thoracoscopy, endoscopy, exotics.

Veterinary Endosurgery (1998)

Freeman, Mosby

First major text on veterinary laparoscopy and thoracoscopy.

BSAVA Manual of Canine and Feline Endoscopy and Endosurgery (2008)

Lhermette, Sobel

Overview of equipment and set up, flexible and ridged endoscopy. Not a great focus on laparoscopy but covers most basic procedures. A good introduction and would be of interest to both medics and surgeons in the practice.

Veterinary Endoscopy for the Small Animal Practitioner (2004)

McCarthy, Saunders

Focussed on flexible endoscopy, but has some sections on basic laparoscopy and rigid endoscopy.

Small Animal Arthroscopy (2003)

Beale, Hulse, Schultz, Whitney, Elsevier

Essential reading if considering adding arthroscopy to the range of services the laparoscopic equipment can be adapted for.