INSTRUMENTS FOR LAPAROSCOPIC SURGERY

Shivshankar Sastry

cybersurg@geocities.com

http://www.geocities.com/cybersurg.geo

Any surgical procedure, whether open or Laparoscopic, requires two basic steps:

1) Access and exposure of the part to be operated

2) The actual operation itself

Laparoscopic surgery differs from open surgery in the method of access because the incisions used are small holes, and a special telescope is used to illuminate and see the operative field, and for exposure the usual method is to insufflate the area with a gas to create space for operative manipulation. Based on these two requirements laparoscopic surgical equipment can be classified into two broad categories

1) Equipment for access and exposure

2) Hand instruments for the actual operative procedure.

These groups will be discussed individually.

EQUIPMENT FOR ACCESS AND EXPOSURE

This requires:

1) A telescope - usually a 10 mm diameter, 25 cm long rod lens for viewing with additional parallel optic fibres to allow light from an external source. The telescope looks like a fat cystoscope, with an eyepiece for direct viewing or fixing of a camera (see 2 below), and a "side branch" at right angles to allow the attachment of a light transmitting cable carrying light from a light source. (see 3 below)

2) A laparoscopic "camera". This is a special lightweight attachment that is fixed to the eyepiece of the telescope and is able to pick up a video image of whatever is seen in the telescope. The video signal is transmitted via a cable to a "video processing unit" - an electronic box that converts the signals into a picture that can be seen on a TV set or special video monitor. The camera and cable are designed so that they can be sterilized in glutaraldehyde.

3) A high performance halogen or Xenon light source with a fibre-optic cable to transmit the light from the light source to the telescope, which has a special attachment point for the light cable.

4) TV or video monitor - to see the image. High resolution "medical" monitors display colours more accurately, but are more expensive. However, the less expensive ordinary TV sets can be used for most routine operative work.

5) An insufflator that can deliver carbon dioxide gas from a high pressure cylinder to the patient at a low and accurately controlled pressure and at a high rate if necessary.

6) Cylinder of carbon dioxide gas

7) A suction irrigation unit: A special unit that can be used both for good quality suction and high power irrigation in laparoscopic surgery is useful, but the majority of laparoscopic surgical operations can be done without this unit, by using ordinary OT suction and gravity irrigation when needed.

8) Ancillary equipment: This includes a Constant Voltage transformer (CVT) to protect the sensitive electronic equipment against damage due to very high or very low voltage power supply, cables to connect the TV/Monitor to the camera control unit, a tube to transmit carbon dioxide from the insufflator to the patient, and minor items such as brushes to clean the equipment and telescope anti-fog solution. A cautery machine and cable is essential.

 

HAND INSTRUMENTS FOR LAPAROSCOPIC SURGERY

Hand instruments in laparoscopic surgery serve the same basic functions as open surgical instruments - i.e. there are graspers, scissors, needle holders and retractors, but all the instruments are long and narrow, and have small jaws that allow the introduction and use of the instruments through narrow tubes (called "cannulae" or "ports") placed through the abdominal wall. A unique instrument in Laparoscopic surgery is a "clip applicator"

In addition one needs to select at least four trocars and cannulas. Since most instruments are either 5 to 5.5mm or 10 to 11 mm in diameter, four trocar and cannula sets are usually adequate - with two being 5.5mm and two of 11 mm, along with a "reducer" that allows the use of a 5 mm instrument in a 10 or 11 mm cannula.

HOW TO SELECT INSTRUMENTS FOR LAPAROSCOPIC SURGERY

The first requirement is to decide what the equipment is going to be used for. Typically, equipment is used for Laparoscopic cholecystectomy, appendicectomy, and laparoscopic gynaecology, and for diagnostic laparoscopy. A list of basic equipment for this is given below, along with the number required. If most operations can be done without a particular item then the word "optional" is written beside the name of the instrument.

It is assumed that the operating theatre is of adequate size and has a standard operating table capable of being tilted in various directions with an X-ray transparent top.

1) Camera unit - (sterilizable head and cable, video control unit)

2) Connector cables from camera to monitor

3) Video Monitor

4) Light Source

5) Light transmission fibre-optic cable

6) Insufflator

7) Carbon Dioxide Cylinder

8) Carbon dioxide pressure regulator valve (optional - see description below)

9) Tubing and Luer-lock adapter for carbon dioxide to patient

10 Suction irrigation apparatus (optional)

11) Cautery machine with cables and foot control

12) Power control equipment (Transformer/spike and surge suppresser)

13) Power extension cord

14) Telescope

15) Trocars and cannulas- 2 x 11mm, 2 x 5.5mm, 11 to 5.5mm reducer(1), 11-7mm reducer(optional)

16) Verress Needle (optional)

17) 2 Atraumatic graspers

18) 1 toothed grasper

19) 1 curved dissector

20) 1 clip applicator with suitable clips

21) 1 dissection hook

22) 1 pair scissors

23) 1 suction irrigation cannula

24) 1 sterilization ring applicator (if sterilization is to be done)

25) 1 pair hook scissors (optional)

26) 1 cautery spatula (optional)

27) 1 gallstone retrieving forceps (optional)

28) 1 needle holder (optional)

Given below is a set of guidelines on how to select and buy some of the above list of instruments.

THE CAMERA UNIT:

The new buyer is faced with a bewildering array of choices of equipment from many manufacturers. The camera is a vital unit and one must not automatically select the cheapest available without looking at many.

Compare the weight of the camera head between several machines - and see which ones are lighter and less bulky. The lighter ones are easier to handle in a long operation. Make sure that the camera head can be adequately sterilized by immersion in glutaraldehyde, and whether the whole connecting cable can be sterilized or whether the far end of the cable has to remain outside the sterilizing liquid. Find out the cost of replacing the cable if it is broken and whether the company can do it.

Cameras are available as single chip or 3 chip. Single chip cameras are not necessarily inferior to 3 chip cameras - and single chip cameras have been used by surgeons for thousands of operations for many years. An ability to focus the camera is essential, and an ability for the camera to work in low light is preferable. It is not essential to have features like remote focusing, auto white balance and digital zoom. These are useful features in some cases, but not 100% essential.

Try and inquire about the background of the company that is selling the equipment. Some well known equipment suppliers have been dealing with the same brand name for years and have set up a wide service network. Ideally a service centre should be near where you intend to use the equipment. Some other equipment manufacturers sell one brand for a few years and then stop dealing with that brand and shift over to another brand and then refuse to service the equipment they supplied you a few years before. This problem is less likely to occur with some major well known brands that have maintained the same dealer network for many years. Check how long the dealer has been selling his brand for - many foreign manufacturers do not care about service back up as long as they can sell a few pieces and make a profit.

VIDEO MONITOR

Dedicated high resolution "medical monitors" are available and may be selected. It is entirely possible to operate safely with a good quality colour TV set. Make sure that the TV set has a video jack (Called an RCA female adapter for video input)to allow video signals to be fed. A 14 inch monitor is adequate for laparoscopic work. Bigger monitors are not necessarily better - the occupy more space in an operating theatre that may already be crowded with equipment, and even small movements are magnified more in a big monitor leading to some degree of eye strain during long operations.

LIGHT SOURCE

Two types are available. The less expensive Halogen type and the more expensive Xenon light source. Xenon sources are really bright and nice to work with - but some brands are not that good and have a high bulb failure rate in the power fluctuations we have in India, and Xenon bulbs are expensive to replace. If a halogen light source is selected, a minimum 250 watt source is essential - a 150 watt source may not be sufficiently bright. Remember that the thinner your telescope, the brighter your light needs to be. If you are using a 10 mm scope, even 150 watts of light may be enough with a good camera, but if you are using thinner (5mm or 2-3mm) telescopes, be sure to select the brightest light source you can afford to buy.

4) Light transmission cable

This should be sufficiently long (2 metres) and the internal fibre bundle should be thick enough (5 mm at least) to allow efficient transmission of light to the patient.

INSUFFLATOR:

The insufflator delivers carbon dioxide gas at a carefully controlled rate and pressure to the patient. The source of gas is a high pressure cylinder, and the pressure is stepped down by the insufflator. An insufflator is a crucial item, and for a new laparoscopy unit that is being set up with a great deal of expense there may be a tendency to reduce expenditure by buying a manual insufflator rather than an automatic electronically controlled one. This is not advisable. Manual insufflators require a lot of attention during prolonged operations and do not deliver gas at a sufficiently high rate - which is a disadvantage in some operations. Also, electronic insufflators are programmable to maintain an accurate value of intra-abdominal pressure without any attention, and they have warning lights or audible signals to indicate if there is a problem. It is well worth spending the extra money to buy an electronic insufflator unless the operations planned are very short procedures such as sterilizations or diagnostic laparoscopies. An automatic insufflator with a maximum flow rate of 10 litres per minute or higher is an asset.

The more expensive insufflators come with add-ons such as a heating element to heat up the cold gas before it reaches the patient. In general, unheated gas does not seem to be a source of worry in standard laparoscopic procedures performed at hot ambient temperatures prevalent in India. However, in very prolonged laparoscopic surgery where hundreds of litres of gas are used, the cold gas may be a contributory factor in hypothermia.

Disposable filters for the carbon dioxide gas are available. Filters slow down the gas supply rate, and are not commonly used. There seem to be no untoward complications resulting from the non-use of filters.

CARBON DIOXIDE CYLINDER:

This is essential - and Medical Grade carbon dioxide is available in cylinders of varying sizes. Most foreign made insufflators are designed to accept gas from small "pin index" type cylinders which may contain 1-2 Kg of gas. The "pin index" standard does not have a safety valve and is therefore is not accepted in India and larger Indian cylinders need to be fitted with a special pin index adapter so that the gas delivery tube from the insufflator can be fitted to the cylinder. It is standard practice to have a large cylinder of carbon dioxide gas stocked in the operating theatre. This gas is under very high pressure and needs to be connected to the insufflator through a pressure reducing valve and a pin index adapter if necessary. The person who supplies you the insufflator should be asked to arrange for these extra accessories.

CAUTERY MACHINE:

A good cautery machine is essential for laparoscopic surgery, and the machine should have foot controls for monopolar cautery, and the cautery cable should have a "female" end on the patient side, because most laparoscopic surgical instruments have a "male" adapter for cautery. (Please note that most standard cautery cables have a "male" adapter at the patient side.) Also, ensure that all the laparoscopic instruments have male adapters to suit the female cautery adapter. When choosing equipment from different manufacturers it is easy to forget this and an instrument may be unusable during surgery because it has a male adapter rather than a female one.

Monopolar cautery has inherent risks - although it is widely used. The risk can be reduced by using a bipolar cautery machine with appropriate instruments.

POWER CONTROL EQUIPMENT:

A back up emergency generator is essential for any hospital that performs laparoscopic surgery. The generator needs to be rated at a minimum of 2.5 KVA to provide enough power for laparoscopic equipment, cautery, lights and suction. Also, power supply can be very "dirty" with voltage variation that can damage expensive equipment. Some sort of stabilizer or surge/spike suppresser is essential for trouble free operation of electronic equipment.

TELESCOPE:

Most commonly used telescopes are 10 mm in diameter. 7 mm telescopes were commonly used for gynaecologic laparoscopy before the advent of video-laparoscopic surgery. One can also get 2mm, 3mm and 5 mm telescopes for various purposes, but a good standard working telescope should be 10mm in diameter with a 0 (zero) degree objective lens for viewing straight ahead. 30 degree telescopes can be extremely useful in certain situations, but are more difficult to use for relatively inexperienced users who are starting laparoscopic surgery.

TROCARS AND CANNULAS:

These may be re-usable or disposable. Disposable ones are available with various innovations to increase speed and safety in insertion. Unfortunately the high cost of single use disposable ports makes them virtually useless in the Indian situation. Resterilizing disposable ports for re-use is practically impossible because blood and tissues enter into spaces that cannot be cleaned. Re-use of disposable ports is mentioned only to be condemned. The only type of "disposable" ports that can be cleaned thoroughly and re-sterilized by Ethylene Oxide or Glutaraldehyde are the so called "Apple" ports and these are highly recommended as a cost-effective solution. In all other cases, only re-usable ports must be bought.

VERRESS NEEDLE:

This is a spring loaded needle that is used to make a blind first puncture for laparoscopic surgery. By using this there is a small but unavoidable incidence of injury to bowel or great vessels as the insertion is blind. A Verress needle can be dispensed with altogether by use of the "open entry" technique in which the peritoneal cavity is entered under vision.

HAND INSTRUMENTS:

Instruments are available from dozens of companies from Indian and foreign sources - and the buyer has a wide choice of price and quality. it is important to check that all instruments that use monopolar cautery have the same type (usually "male") cautery adapter, and that the cautery cable has a female type adapter.

REFERENCES:

1) Laparoscopic Abdominal Operations, Graber et al, McGraw Hill, 1993

2) Laparoscopic Surgery in developing countries, T.E.Udwadia, Jaypee, 1997

3) Fundamentals of Laparoscopic Surgery, Lawrence Way et al, Churchill Livingstone 1995