Principles of laporoscopic surgery

Principles of laporoscopic surgery

MINIMAL ACCESS THERAPY


1.AIMS AND OBJECTIVES

1.1.Aims

The aims of the course is that :

  • Participants should be able to perform, with confidence, basic procedures such as laparoscopic cholecystectomy or lapraroscopic appendicectomy under the initial supervision of an experienced laparoscopic surgeon.
  • They should also be able to act as proficient first assistant at laparoscopic procedures.

1.2.Objectives

Our objectives are that the student should be able to:

  • Identify and use basic endoscopic equipment.
  • Prepare the patient.
  • Induce a pneumoperitoneum using a safe technique.
  • Perform a systematic laparoscopic examination and recognise abnormalities.
  • Master the techniques for safe instrumentation.
  • Understanding the principles and hazards of electrocautery.
  • Understand the factors governing port placement and retraction.
  • Tie off structures using clips and performed loop.
  • Be familiar with procedures for gall bladder extraction.

1.3.Patient information

It is very important that all patients undergoing laparoscopic surgery understand that:

  • you cannot guarantee to perform their operation laparoscopically – only by the safest method for them at the time of surgery.
  • they will have several small incision.
  • even though the incisions are small all operations have associated risks.
  • they may have post operative shoulder tip pain.
  • they may have to stay in hospital longer than expected if things are not straight forward.
  • consequences of open surgery will follow, should it become necessary.

1.4.Theatre Staff and Preparation

  • The theatre must naturally be able to supply the relevant equipment and instruments for a procedure.
  • In addition appropriate instruments should be immediately available to cope with emergency complications such as major bleeding.
  • Spare bulbs for the light source and a spare gas cylinder should be available.
  • This type of surgery places great reliance on technology. If you can begin your laparoscopic experience in a theatre where everyone is familiar with their part in the proceedings it will be to your advantage.

2.PREPARATION OF THE PATIENT

For laparoscopic cholecystectomy :

  • Prophylactic antibiotics.
  • A standard anaesthesia with appropriate monitoring.
  • The patient should empty the bladder just prior to the procedure. Avoid unnecessary catheterisation.
  • A naso-gastric tube is used to deflate the stomach.
  • The patient is placed supine.
  • As the patient will be tipped during the procedure appropriate measures to ensure their safety are instituted.

3.BASIC INSTRUMENTATION

Most endoscopic procedures require a mixture of sharp and blunt techniques, often using the same instrument in a number of different ways. 

Sharp Dissection Instruments  Blunt Dissection Instruments  Other Instruments  Methods 
Scissors 
Electrocautery hook 
Electrocautery spatula 
Electrocautery knife
Closed scissors, tips used as blunt dissector 
Scissors points used to separate by spreading 
Grasper, straight and curved 
Inactive suction cannula
Harmonic scalpel 
Hydrojet 
Ultrasound 
Cryosurgery 
Laser
Distraction 
Separation
Teasing 
Wiping

 

3.1.Haemostasis during endoscopic surgery

  • Endoscopic surgery is controlled also entirely by vision alone.
  • Any loss of view will result in loss of control and hence reducing safety.
  • Haemorrhage, even to a minor extent, tends to obscure the operative field and consequently is to be avoided.
  • This means that vessels of a size that in open surgery could be divided without particular attention need to be secured prior to division when working endoscopically.
  • Dissection must be more meticulous to proceed smoothly.
  • Magnification of tissues by the endoscope may initially confuse an inexperienced surgeon as to the severity of the bleeding.
  • A moderate bleed can appear torrential but an inexperienced endoscopic surgeon is well advised to convert should he have any doubt about his ability to control the situation expeditiously.

3.1.1.Techniques to assist in control of bleeding

  • Pressure on the area supplied by a retracting grasper pressing neighboring tissue on to the area.
  • Pressure from a pledget.
  • Pressure and suction / irrigation with the sucker.
  • Picking up the vessel with a grasper.

3.1.2.Methods of securing haemostasis

  • Coagulation
  • Loop
  • Ligature
  • Clipping
  • Pressure
  • Other agents

4. ACCESS

4.1.Pneumoperitoneum and Trocar Insertion

One of the most dangerous complications of endoscopic surgery is bleeding due to accidental vessel damage during this initial stage. Establish and follow a safe routine. A closed technique or open technique can achieve access.

4.2.Closed Access

4.2.1.Veress needle insertion

  • The standard method of insufflation of the abdominal cavity is via a Veress needle inserted through a small skin incision in the infra umbilical region.
  • The Veress needle consists of a sharp needle with an internal, spring loaded trocar. The trocar is blunt ended with a lumen and side hole.
  • CO2 is use for insufflation as it is 200 times as diffusible as O2, is rapidly cleared from the body by the lungs and will not support combustion. Insufflation “retracts” the anterior abdominal wall exposing the operative field.
  • The insufflator used should monitors insufflation pressure, gas flow rate and volume of gas consumed. It automatically maintains the intra-abdominal pressure at the predetermined level.

4.2.2.Trocar Insertion

  • The first trocar and cannula inserted is an 11 mm / 6mm trocar to accommodate a 10 mm / 5mm telescope and leave sufficient space in the trocar for rapid gas insufflation if required.
  • Following insufflation, the Veress needle is removed and the trocar inserted with care at the same point, using a blind technique (see Step by step). The telescope can then be introduced.
  • Subsequent trocars are inserted under direct vision at locations appropriate for the procedure and to the anatomy of the individual.
  • Different sized converters (gaskets) are available with some makes of disposable cannulae to maintain the gas seal.

4.2.3.Step by step Veress Needle insertion

  • Check and set the insufflator pressure level and flow rate.
  • Initial flow rates should be set at 1-2 litre/min.
  • An initial pressure setting of 10.0 – 15.0 mmHg is recommended.
  • Connect up gas supply to Veress needle.
  • Check gas flow, needle patency and spring loaded central blunt stylet
  • Palpation test : Assessment abdominal wall thickness by palpation with the fingers down to the aorta.
  • Skin incision.
  • Tense abdominal wall and insert needle : Hold the needle at a point along its shaft at a distance from the tip that equates with that estimated by palpation as the abdominal wall thickness. The other hand holds up the abdominal wall, providing counter tension as the needle is “threaded” in. You should be able to feel the needle puncture two distinct layers.Once the sharp tip enters the peritoneal cavity, the spring-loaded blunt stylet is released with an audible (palpable) click.
  • Check that the needle is in the correct position. A number of tests exist to confirm correct positioning of the needle tip :
    • Aspiration: uses a saline filled syringe.
    • Saline drop test: uses a drop of saline in the Veress needle hub.
    • Negative pressure test: The insufflator dial should be negative or less than 5 mm. Hg.

                Early insufflations pressures: the insufflations pressure should be low and the flow should  be very near the    maximum flow you have set. The number of passes required should be recorded. If a small amount of blood is aspirated, reinsertion is justified.

                If large amounts of blood escape up the needle laparotomy is indicated. If bowel content is aspirated the needle is withdrawn and reinserted in another location. Subsequent inspection and adequate treatment for bowel injury is mandatory.)

  • Insufflate. After a minimum of 1 litre of gas has been insufflated and needle position has been confirmed the rate may be increased for more rapid filling. Periodic checks should be made of symmetric distension and abdominal resonance.
  • Close the gas tap on the needle and withdraw it, once the desired pressure has been reached.

4.2.4.Step by step insertion of first cannula

  • Enlarge the sub umbilical skin incision.
  • Check trocar and cannula.
  • Insert trocar and cannula into abdominal cavity and immediately remove trocar. The trocar should be inserted in a direction parallel to the aorta and pointing towards the centre of the pelvic cavity. Power should be applied from the wrist and not the shoulder. The index finger should be used along the side of the cannula to limit penetration.
  • Connect the gas supply.
  • Insert the telescope.

The telescope is pre heated. A stainless steel vacuum flask with warm sterile saline, which stands on the instrument trolley, is used but other arrangements can be made. This helps to prevent misting of the lens on insertion into the warm, moist abdominal atmosphere. Should the lens become smeared during the procedure it can be dipped in saline and wiped with a gauze swab. Wiping on organs such as the liver is not encouraged as it leads to protein build up on the lens.Inspect the abdominal cavity for

  • Damage
  • Adhesions
  • Multiple pathology
  • Feasibility of surgery

4.3.Open access

  • A sub-umbilical incision is made.
  • Fascia is visualised & grasped with tissue forceps.
  • Under vision, the fascia is incised and the cut edges are grasped with tissue forceps.
  • Fascial sutures are taken under vision.
  • Blunt Hasson’s trocar 11mm / 6mm is introduced.
  • Position checked by early insufflation pressures.

5. COAGULATION

Electro-coagulation using HF current may be monopolar or bipolar. Bipolar is safer in dissections were space is restricted. When a monopolar system is used the safest form is SOFT coagulation. This setting maintains the voltage below 200 V so that sparks are not generated. Soft coagulation is recommended for endoscopic use. It may be applied by insulated graspers, hook, spatula or scissors.

5.1.Safety Considerations in Minimal access surgery

There are three ways by which current can leak into undesirable situations:

5.1.1.Direct coupling

This occurs when the diathermy is activated when the active electrode is near a metal instrument. The second instrument becomes energised. This energy will seek a pathway to complete the circuit to the patient electrode. Neighboring structures like bowel can become injured.

  • DO NOT ACTIVATE THE GENERATOR WHILE THE ACTIVE ELECTRODE IS TOUCHING OR IN CLOSE PROXIMITY TO ANOTHER METAL OBJECT.

5.1.2.Insulation failure

Faulty instruments cause this. Insulation “breaks” can cause “leaks”. This is more common when high voltage coagulation current is used.

  • ALWAYS CHECK INSTRUMENTS FOR INSULATION BREAKS. MINIMISE THIS DANGER BY KEEPNG THE COAGULATION CURRENT SETTING TO BELOW 200V.

5.1.3.Capacitance coupling

Capacitance occurs when a non-conductor of electricity separates two conductors. This typically occurs between an insulted instrument and a metal cannula. An electrostatic current field is created and it can induce current in the metal cannula. Plastic cannula does not eliminate this problem completely as the patient’s body can act as a conductor. The worst situation occurs when a metal reducer is used in a plastic cannula!

  • USE ALL METAL CANNULA SYSTEMS. INVEST IN LATEST TECHNOLOGY- RECENT DIATHERMY MACHINE WHICH COME WITH ACTIVE ELECTRODE MONITORING, WHEREIN EXCESS STRAY CURRENT AUTOMATICALLY SWITCHES THE GENERATOR OFF.

Dr.R.Parivalavan MS,DipNB,FRCSEd.
Consultant General Surgeon
Email : [email protected]  

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