Pneumoperitoneum and Trocar Insertion
Bleeding due to accidental damage to a major vessel during this initial stage is one of the most dangerous complications of endoscopic surgery.
Establish and follow a safe routine!
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. Disposable and non disposable metal Veress needles are available commercial in different lengths i.e. long for obese patients, short for thin or paediatric patients.
Insufflation via the Veress needle creates a cushion of gas over the bowel for insertion of the first trocar. Insufflation then retracts the anterior abdominal wall exposing the operative field. CO2 is use for insufflation as it is 200 times as diffusible as 02, is rapidly cleared from the body by the lungs and will not support combustion. For short diagnostic procedures under local anaesthetic, N20 may be used.
The insufflator is used to monitor insufflation pressure, gas flow rate and volume of gas consumed (see Equipment Details and Step by Step). It automatically maintains the intrabdominal pressure at the predetermined level.
Flow rate, volume and pressure settings for the insufflator
Initial setting 1 - 1.5 litre per minute
Maximum permitted setting 5 - 6 litres per minute
Total abdominal fill approx. 3 litres
Total for whole procedure 3 - 100 litres
Average initial setting 12 mm Hg
Range 10- 15 mm Hg
Trocar and cannula designs currently available have a number of basic features in common. They come in a variety of sizes and the central trocar may have a pyramidal, conical or rounded tip. They have a valve system and a gas input with a tap. Please see instrument Picture gallery of www.laparoscopyhospital.com
The disposable cannulae have flap valves and the care should be taken when passing instruments through the port. Some disposable cannulae have a safety system. A cylinder jumps forward after penetration of abdominal wall and forms a shield over the sharp trocar tip. This is not foolproof due to shield lag. In the most recent disposable cannulae the trocar itself is spring loaded. We use a disposable cannula for the initial port. New designs of cannula, some quite minimalist are currently under investigation.
The first trocar and cannula inserted is an 11 mm disposable trocar. This will accommodate a 10 mm telescope and leave sufficient space in the cannula 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 Section 3: Step by step). The gas line is connected and the telescope introduced.
Subsequent trocars are inserted under direct vision at locations appropriate for the procedure and to the anatomy of the individual. The positioning of operative ports is an important factor in determining the ease with which a procedure is carried out. It is a skill which must be learnt.
Non-disposable metal cannulae have trumpet or flap valves. The flap valves can be manually opened when introducing or removing an instrument. This avoids damaging delicate instruments or blunting sharp ones. A reducer tube is used with large cannulae to maintain the gas seal and this automatically opens the valve.
A number of cannulae modeled on the Hassan cannula are available for use during open laparoscopic procedures. Different sized converters (gaskets) are available for disposable cannulae to maintain the gas seal.
Some surgeons are unhappy with the use of the blind technique and there are circumstances where it is inappropriate. An open technique, which involves creating a minilaparotomy into which a special cannula is inserted, may be adopted. This procedure is not without its own complications and also requires skilled execution if these are to be avoided.
The Hasson trocar system was developed for laparoscopy in patients who have had a previous laparotomy. An access wound was made using traditional open techniques and the Hasson port was designed to help both fix the port and seal this larger wound round the port. It requires the use of sutures. In World Laparoscopy Hospital, we have changed from the Veress needle access technique to what is referred to as the Scandinavian technique. This involved making a small entry wound directly through the scar tissue of the umbilicus and then dilating this up by passage of a blunt, preferable conically tipped trocar and cannula.
The scarred abdomen
Additional precautions are necessary during the access procedure in patients with abdominal scars. It may be inadvisable to insert the Veress needle below the umbilicus in a patient with a scar in this area (or an umbilical hernia). Insufflation through an unscarred such as subcostal region, or if this is scarred, the iliac fossae, is better. A general guideline is to choose the quadrant of the abdomen opposite to that of the scar.
Ultrasound visceral Slide
There is a simple preoperative test that can help to identify a safe region for Veress needle insertion in the scarred abdomen. The preoperative detection of anterior abdominal wall adhesions by ultrasonic scanning is a simple and reliable technique (Ref .Sigel B, Golub RM, Laurie A et al. and Technique of ultrasonic detection and mapping of abdominal wall adhesions. Surgical Endoscopy, 1991:5: 161-165.)
Once the Veress needle has been inserted, there should still be concern about the risk of causing damage with the trocar. The following techniques have been described for this situation:
A fine spinal needle, attached to a saline filled syringe, is passed into the inflated abdomen. As the needle is slowly advanced, while aspirating, a stream of bubbles is seen in the saline until the needle tip contacts tissue. The needle is then withdrawn towards the surface and the process repeated several times, in different directions, thereby "mapping" the gas filled cavity and any solid structures.
Visually Guided Entry
A technique which uses cannula and 0 degree telescope to allow direct visualization of the entry tract. Specialist cannula such as Visiport or Optiview uses this principle, first described by Semm.
How to do laparoscopy on an abdomen with previous abdominal scar?
The patient with previous abdominal surgery is at high risk for minimal access surgery in those patients following techniques should be used
1. The open insufflation technique
2. Pneumoperitoneum should be created with a veress needle by selecting an alternate site of insertion distant from the old abdominal incision.
3 Insufflations with a veress needle inserted in posterior fornix or Trans uterus rout
4. Insertion of optical trocar- primary port.
This is a very safe technique to enter the abdomen, especially in patients with scarred abdomen from multiple previous surgeries.
This is an open technique where surgeon can see what he is doing. It is performed in an area of the abdomen distant from previous scars and likely to be free of adhesions. After the induction of anesthesia a one c.m horizontal incision is made. Blunt dissection is carried out until the underlying fascia is identified. The fascia is elevated with a pair of Kocher's clamps. Adherent subcutaneous tissue is gently dissected free. It is then incised to permit entry of trocar into the peritoneal cavity. Two heavy, absorbable sutures are placed on either side of the fascial incision just like repair of umbilical hernia. Care must be taken when applying these sutures not to injury the underlying viscera. The Kocher clamps are next removed, and 10-mm blunt trocar is advanced into the peritoneal cavity. The obturator is removed and the sleeve is secured in position with the previously placed two sutures. The sleeve of the trocar is wrapped with Vaseline gauze to prevent leakage of insufflated gas around the trocar.
Open Fielding technique:
This technique developed by Fielding in1992 involves a small incision over the everted umbilicus at a point where the skin and peritoneum are adjacent. Pneumoperitoneum can be created using Fielding technique in patients with abdominal incisions from previous surgery providing there is no midline incision, portal hypertension and re-canalized umbilical vein, and umbilical abnormalities such as urachal cyst, sinus or umbilical hernia present. A suture is not usually required to prevent gas leakage because the umbilicus has been everted (so the angle of insertion of the laparoscopic port becomes oblique) and the incision required is relatively small. However, one may be needed to stabilize the port. Thorough skin preparation of the umbilicus is carried out and the everted umbilicus (with toothed grasping forceps) is incised from the apex in a caudal direction. Two small retractors are inserted to expose the cylindrical umbilical tube running from the undersurface of the umbilical skin down to the linea alba. This tube is then cut from its apex downwards towards its junction with the linea alba. Further blunt dissection through this plane permits direct entry into the peritoneum. Once the peritoneal cavity is breached the laparoscopic port (without trocar) can then be inserted directly and insufflations started. A blunt internal trocar facilitates insertion of this port and an external grip that can be attached to the port assist to secure it in position.
The advantages of using the open technique are many:
- The incidence of injury to adhesive although not eliminated is significantly reduced by entry into the peritoneal cavity under direct vision.
- There is a decrease risk of injury to the retroperitoneal vessels. The obturator is blunt and the angle of entry allows the surgeon to maneuver the cannulas at an angle, which avoids viscera, while still assuring peritoneal placement.
- The risk of extra peritoneal insufflations is eliminated. Placement under direct vision ensures that insufflation of gas is actually into the peritoneal cavity.
- The likelihood of hernia formation is decreased because the fascia is closed as part of the technique
- In experience hands the open technique is cost effective. The Hasson technique does not increase the operative time required creating a pneumoperitoneum and may even lessen it.
Alternative sites for introducing veress needle.
For avoiding the injury to the adhered portion of bowel in the patient with previous abdominal surgeries the alternative site for the introduction of veress needle can be choose other than umbilicus.
For Previous laparotomy with midline incision:
For a previously operated abdomen with a midline incision, Veress needle should placed in the upper left quadrant of the abdomen just lateral to the rectus sheath. The preperitoneal space in hypochondriac region is more easily insufflated than at the umbilicus. The veress needle at hypochondriac region need to be passed more deeply into the abdomen in order to enter the peritoneal cavity because all the layers of abdomen are present here and there is a thick layer of muscle as well. The right upper quadrant should be avoided because of the size of the liver and the presence of the falciform ligament. There is some report of injury to liver if the liver is enlarged or the careless insertion of veress needle to right hypochondrium is performed.
For a previous laparotomy with upper midline incision:
In a patient with scar on the upper midline of abdomen the veress needle should be placed in the right lower quadrant, the left lower quadrant should generally avoided since in older patients there are usually sigmoid adhesions in the left lower quadrant.
For previously operated abdomen with a solitary incision in an upper or lower abdominal quadrant.
In a patient with the scar in the upper or lower abdominal quadrant the Veress needle should be passed in the opposite abdominal quadrant just lateral to the rectus muscle. The left lower and light upper quadrant should be avoided if it is possible. For patient with previously operated abdomen in multiple quadrants: In these patients a veress needle or open cannula in an area farthest from the existing abdominal scar should used. When there is any confusion regarding the presence of adhesion inside the abdomen where veress needle has to go, the open-cannula technique should be used.
Some surgeons prefer to introduce veress needle through the posterior fornix or though uterus in female with previous abdominal surgery. Although this method of pneumoperitoneum is now very popular the placement of a needle via the posterior fornix has been demonstrated to be safe. If this rout of pneumoperitoneum has been chosen than the needle must be placed in the midline about 1.75 cm behind the junction of the vault and smooth epithelium of external OS.
Rout of insufflation.
Insufflation with an Optical trocar (Visiport)
This is one of the techniques used for performing laparoscopic procedures in patient with previous scarred abdomen. An incision of 1 cm long is made in the area of the abdominal wall distant from the previous scars. The littlewood forceps is used to elevate the abdomen. The Visiport optical trocar is introduced with telescope. The optical trocar is advanced slowly through the different planes of the abdominal wall. The blade at the tip of the visiport cuts the tissue which is visible also and there is very less chance of injury to intra-abdominal organ if the surgeon is experienced.