腹部接入技术

Abdominal Access technique

“Access is the Key of Success”

Prof. Dr. R. K. Mishra. MRCS,M.MAS (U.K).

        In minimal access surgery technique of first entry inside the human body with telescope and instruments is called access technique. Technique of access is different for different minimal access surgical procedures. For thoracoscopy, retroperitoneoscopy, axilloscopy all have completely different way of access. In this chapter we will discuss the various abdominal access technique used in laparoscopy.

First entry or access in laparoscopy is of two types

1.      Closed access

In closed access technique pneumoperitoneum is created by Veress needle. This is a blind technique and most commonly practiced way of access by surgeons and gynaecologists worldwide. Closed technique of access merely by veress needle insertion and creation of pneumoperitoneum is a easy way of access but it is not possible in some of the minimal access surgical procedures like axilloscopy, retroperitoneoscopy and totally extra-peritoneal approach of hernia repair. In general closed technique by veress needle is possible only if there is a pre-formed cavity like abdomen.

1.      Open access

Direct entry by open technique, without creating pneumoperitoneum and insufflator is connected once blunt trocar is inside the abdominal cavity under direct vision. There are various way of open access like Hassons technique, Scandinavian technique, Fielding technique.

Some surgeon and gynaecologists practices blind trocar insertion without pneumoperitoneum. The incidence of injury due to this type of Access is much higher. This type of direct trocar entry is practiced by gynaecologists for sterilization. Sterilization may be performed because in multipara patients the lower abdominal wall is lax; making the fascia thinner and easy elevation by hand is possible.

Bleeding due to accidental damage to a major vessel during this initial stage is one of the most dangerous complications of laparoscopic surgery.

For safe access we should establish and follow a safe routine!

Closed access techniqueVeress needle insertion

The standard method of insufflations 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 pediatric patients. . Before using veress needle every time it should be checked for its patancy and spring action.

Insufflation via the Veress needle creates a cushion of gas over the bowel for insertion of the first trocar. Veress needle is for creation of pneumoperitoneum is used all over world by most of the laparoscopic surgeon. Insufflation then retracts the anterior abdominal wall exposing the operative field.

Preparation of patient:

The patient should be nil orally since the morning of surgery. In some of the procedure like LAVH or colorectal surgery where distended bowel may interfere it is good to prepare bowel prior to the night of surgery by giving some mild purgative. Bowel preparation can minimize the need of accessory port to retract the bowel.

Before coming to operation theatre patient should always void urine. The full urinary bladder may get perforation at the time of insertion of veress needle or trocar. If the laparoscopic procedure is going to be performed of upper abdomen then Foleys catheterization is not necessary. If gynaecological operative surgery or any general surgical lower abdominal procedure has to be performed (like hernia or adhesiolysis) it is wise to insert Foleys catheter.

If surgeon is going to perform any upper abdominal procedure like Cholecystectomy, Fundoplication, Duodenal perforation, Hiatus hernia etc it is good practice to have nasogastric tube in place. A distended stomach will not allow proper visualization of callots triangle and then surgeon has to apply more traction over fundus or Hartman pouch and this may cause tenting of CBD followed by accidental injury. In gynaecological or lower abdominal laparoscopic procedure it is not necessary to put nasogastric tube.

In minimal access surgery shaving of skin is not must and if necessary it should be done on operation table it self by surgeon.

Patient position:

If laparoscopy has to be performed, initially at the time of pneumoperitoneum by veress needle patient should be placed supine with 10-20 degrees head down. The benefit of this steep trendelenburg position is that bowel will be pulled up and there will be more room in pelvic cavity for safe entry of veress needle. It is important to remember that patient should be placed in head down position only if surgeon is planning to insert veress needle pointing towards pelvis cavity. If surgeon is planning to insert veress needle perpendicular to abdominal wall as in case of very obese patient or diagnostic laparoscopy in local anaesthesia the patient should be placed in supine position otherwise all the bowel will come just below the umbilicus and there is increased risk of bowel injury.

In Gynaecological laparoscopic procedures or if laparoscopy is planned to be performed together with hysteroscopy, patient should be positioned in lithotomy position & one assistant should be positioned between the leg of patient. Patients leg should be comfortably supported by padded obstretic leg holders or Allen stirrups which minimizes the risk of venous thrombosis. In these procedure surgeon need to use uterine manipulator for proper visualization of female reproductive organs. The assistant seating between the leg of patient will keep on watching the hand movement of surgeon on monitor and he should give traction with the handle of uterine monitor in appropriate direction.

If thoracoscopy or retroperitoneoscopy is planned then patient is placed in lateral position.

Position of surgical team

The laparoscopic surgeon is very much dependent & helpless with eye fixed on monitor. At the time of laparoscopic surgery surgeon is largely depending on the skill of his assistalnt. If the surgery is of upper abdomen french surgeon likes to stand between the legs of patient, popularly known as “French position”. The American surgeons like to operate from left in cases of upper abdominal surgery like Fundoplication & hiatus hernia called as “American position”.

Laparoscopic surgery is not in its infancy stage now. It is not wise to remain stand in any one position & surgeon should walk. In most of the cases at the time of access surgeon should stand on left side of the patient, if surgeon is left handed he should stand right to the patient at the time of access. This helps in inserting veress needle & trocar towards pelvis by dominant hand. Once all the ports are in position then surgeon should come opposite to the side of pathology to start doing surgery. In cholecystectomy, appendectomy, right sided hernia or right ovarian cyst surgeon should stand left to the patient. In left sided pathology like left ovarian cyst and left sided hernia it is ergonomically better for surgeon to stand right to the patient.

In most of the upper abdominal surgery camera assistant should stand left to the surgeon & in lower abdominal surgery he or she should stand right to the surgeon. Camera assistant while holding telescope can pass his or her hand between body and arm of surgeon so that some time surgeon can help him to focus his camera correctly. Camera assistant can be placed opposite to the surgeon to stand but in this case it is better to have two monitor on both the side of patient, one for surgeon and one for camera stand and other members of surgical team.

Choice of Gas for pneumoperitoneum

First Pneumoperitoneum was created by filtered room air. Carbon dioxide & N2O are now preferred gas because of increased risk of air embolism with room air. CO2 is use for insufflation as it is 200 times more diffusible than 02, is rapidly cleared from the body by the lungs and will not support combustion. N2O is only 68% as rapidly absorbed in blood as CO2. N2O has one advantage over CO2 that it has mild analgesic effect, and so causing no pain if diagnostic laparoscopy is performed under local anaesthesia. For short operative procedures like sterilization or drilling, under local anaesthetic N20 may also be used. During prolonged laparoscopic procedure N2O should not be a preferred gas for pneumoperitoneum because it supports combustion better than air. CO2 when come in contact with peritoneal fluid converts into carbonic acid. Carbonic acid irritates diaphragm causing shoulder tip pain & discomfort in abdomen. Carbonic acid has one advantage also that it alters pH of peritoneal fluid (acidotic changes) and it is mild antiseptic so the chances of infection may be slightly less compared to any other gas. Helium gas being inert in nature is also tried in many centers but it does not have any added benefit over CO2.

Site of veress needle entry

There are many sites of veress needle entry tried for veress needle insertion but central location of umbilicus and ability of umbilicus to hide scar makes it most attractive site for primary port.

Is umbilicus safe for access?

Umbilical is good site for access because it is:

·        thinnest abdominal wall (easy access)

·        cosmetically better

·        no significant blood vessels

·        Ergonomically better (centre point of abdomen)

Initially there was controversy regarding use of umbilicus for first port access. There were two fear regarding use of umbilicus

First concern was regarding infection. Umbilicus is a naturally dirty area and many surgeons were having this impression that it may cause infection of port site. The umbilical skin can not be cleaned of all bacteria even with modern iodophor solution. Carson and associates (1997) demonstrated that the bacteria introduced inside the abdominal cavity through this dirty skin but these bacteria do not have many dead cells to act as culture medium to grow and the normal defence mechanism of body destroys these bacteria rapidly. Second fear of using umbilicus was ventral hernia. Umbilicus is the weakest abdominal wall so the chances are more that ventral hernia may develop if umbilicus is used for access. A survey of American Association of Gynecological Laparoscopists members reported in 1994 (Montz et al ). The study was of 3127 surgeons and there were 840 hernia reported. 86% of cases of incisional hernia after laparoscopy were due to unrepaired 10 mm or larger port wound.

Due to these two possible complications of using umbilicus for access, many surgeons started using supra-umbilical or infra-umbilical region of abdominal wall for access. Even the port wound of 10 mm away from the umbilical site was also reported higher incidence of incisional hernia. Recent study has proved that umbilicus does not have increased incidence of infection or ventral hernia compared to other site if few precautions are taken.

1.      Umbilicus should be cleaned meticulously before incision

2.      Rectus sheath of all the 10 mm port should be repaired.

3.      If umbilical route is used for tissue retrieval, infected tissue should be removed after putting in endobag. It should not contaminate the port wound.

4.      Any haematoma formation at the port wound site should be discouraged by maintaining proper haemostasis

Where in umbilicus?

–       Superior or inferior crease of umbilicus, in non obese patients ( for abdominal procedure)

–       Trans-umbilical, in obese patients or if diagnostic laparoscopy is going to be performed under local anesthesia.

In most of the patient inferior crease of umbilicus is best site of incision. This is called as smiling incision. In obese patient trans-umbilical incision is preferred because this area has minimum thickness of fat. In obese patient veress needle should be inserted perpendicular to the abdominal wall because if oblique entry is tried the full length of veress needle will be some where within the fat pad and there is chance of creation of pre-peritoneal space.

Stabilization of umbilicus and incision

Before giving incision along the inferior crease of umbilicus it should be stabilize with the help of two ellis forcep. Once ellis forcep will catch the umbilicus the crease of umbilicus will be everted and it is easy to give smiling incision. Initial 1mm incision with blade no.11 should be given. Some surgeon give 11mm incision in beginning itself but this is not good because gas may leak from the side of puncture of veress needle due to tear in rectus and this will interfere with the quadro-manometric indicator of insufflator. Initial stab wound should be given just skin deep and any puncture of rectus or peritoneum should be avoided.

Introduction of Veress needle

Veress needle should be held like a dart. At the time of insertion there should be 45 degrees of elevation angle (Elevation angle is angle between instrument and body of patient). To get an elevation angle of 45 degree the distal end of the veress needle should be pointed toward anus.

Veress Needle should be held like a dart

To prevent creation of pre-peritoneal slip of tip of veress needle it is necessary that veress needle should be perpendicular to the abdominal wall but there is a fear of injury of great vessels or bowel if veress needle is inserted perpendicular to the abdominal wall. To avoid both the difficulty (Creation of pre-peritoneal space and injury to bowel or great vessels) the lower abdominal wall should be lifted in such a way that it should lie at 90 degree angle in relation to the veress needle but in relation to the body of patient veress needle will be at an angle of 45 degree poined towards anus. Lifting of abdominal wall should be adequate so that the distance of abdominal wall from viscera should increase. If there is less muscle relaxant is given in muscular patient sometime lifting of abdominal wall is difficult. In multipara patient lifting lower abdominal wall is very easy.

For years many surgeons was using towel clip to elevate the abdominal wall. This towel clip technique of lifting abdominal was advocated by Johns Hopkins University but after some time it was realized that towel clip technique increases the distance of skin from rest of the abdominal wall more than distance of abdominal wall from viscera. Abdominal wall should be held full thickness with the help of thenar, hypothenar and all the four fingers. It is lifted in such a way that angle between veress needle to abdominal wall should be 90 degree and angle between veress needle and patient should be 45 degree. At the time of entry of veress needle surgeon can hear and feel two click sounds. The first click sound is due to rectus sheath and second click sound is due to puncture of peritoneum. Anterior and posterior rectus forms one sheath at the level of umbilicus so there will be only one click for rectus.

If any other area of abdominal wall is selected for access surgeon will get three click sounds. Once these two click sould is felt surgeon should stop pushing veress needle further inside and he should use various indicators to know where he is.

Indicators of safe Veress needle insertion:

Needle movement test (Very gentle movement)

Once the veress needle is inside the abdominal cavity the tip of veress needle should be free and if surgeon will gently move the tip of needle there should not be feel of any resistance. It is very important to remember that veress needle should be not moved inside the abdominal cavity much, otherwise there may be risk of laceration of bowel if it is punctured.

Irrigation test

A 10 ml syringe should be taken in one hand and surgeon should try to inject at least 5 ml of normal saline through veress needle. If tip of veress needle is inside the abdominal cavity then there will be free flow of saline otherwise some resistance is felt in injecting saline.

Aspiration test

After injecting saline surgeon should try to aspirate that saline back through veress needle. If the tip of veress needle is in abdominal cavity the irrigated water can not be sucked but if it is in pre-peritoneal space on in muscle fibre of above the rectus the injected water can be aspirated back. At the time of aspiration test if more fluid then irrigated fluid is coming then surgeon should suspect either ascitis or he has perforated urinary bladder or some cyst. If faecal mater is seen then perforation of bladder may be the reason and if blood is coming then the vessel injury is the cause. If any fresh blood or fecal fluid is aspirated in the syringe surgeon should not remove the veress needle and urgent laparotomy is required. Leaving veress needle in position is helpful in two way first it is easy to find the punctured area after laparotomy and secondly the further bleeding will be less.

Hanging drop test

Few drops of saline should be pored over the veress needle and abdominal wall should be lifted slightly if tip of the veress needle is inside the abdominal cavity the hanging drop should be sucked inside because inside the abdomen there is negative pressure. If tip of the veress needle is any where else the hanging drop test will be negative.

Insufflation of gas test, Quadro-manometric test

For safe access surgeon should always see carefully all these four indicators of insufflator at the time of creation of pneumoperitoneum. If the gas is flowing inside the abdominal cavity there should be proportionate rise in actual pressure with total gas used. Suppose only with the entry of 400 to 500 ml of gas, if actual pressure is equal to preset pressure of 12 mm of Hg, that means gas is not going in free abdominal cavity, it may be in pre-peritoneal space or inside omentum or may be in bowel. If gas is flown more than 5 liter without any distension of abdomen that may be due to leakage or gas may be going inside the vessel. With increasing experience, surgeon will immediately realize where he is by seeing these four setting of his insufflator.

Quadro-manometric Indicators of Insufflator

Quadro-manometric indicators are the four important readings of insufflator.

The insufflator is used to monitor

·        Preset Insufflation pressure,

·        Actual Pressure

·        Gas flow rate and

·        Volume of gas consumed

Preset Pressure

This is the pressure adjusted by surgeon before starting isufflation. This is the command given by surgeon to insufflator to keep intra-abdominal pressure at this level.

The preset pressure ideally should be 12 mm of Hg. In any circumstance it should not be more than 18 mm of mercury. The good quality insufflator always keeps intra-abdominal pressure at preset pressure. Whenever intra abdominal pressure decreases due to leak of gas outside, insufflator eject some gas inside to maintain the pressure equal to preset pressure and if intra-abdominal pressure increases due to external pressure, insufflator sucks some gas from abdominal cavity to again maintain the pressure to preset pressure.

When surgeon or gynaecologist wants to perform diagnostic laparoscopy under local anaesthesia, the preset pressure should be set to 8 mm of Hg. In some special situation of axilloscopy or arthroscopy we need to have pressure more than 19mmHg.

Actual Pressure

This is the actual intra-abdominal pressure sensed by insufflator. When veress needle is attached there is some error in actual pressure reading because of resistance of flow of gas through small caliber of veress needle. Since continuous flow of insufflating gas through veress needle usually gives extra 4 to 8 mm Hg of measured pressure by insufflator, the true intra-abdominal pressure can actually determined by switching the flow from insufflator off for a moment. Many microprocessor controlled good quality insufflator deliver pulsatile flow of gas when veress needle is connected, in which the low reading of actual pressure measures the true intra-abdominal pressure.

If there is any major gas leak actual pressure will be less and insufflator will try to maintain the pressure by ejecting gas through its full capacity.

Actual pressure if more than 20 to 25mm of Hg has following disadvantage over hemodynamic status of patient.

·        Decrease venous return due to vena caval compression leading to

a.       Increased chance of DVT (Deep vein thrombosis of calf)

b.      Hidden cardiac ischemia can precipitate due to decrease cardiac output

·        Decrease tidal volume due to diaphragmatic excursion

·        Increase risk of air embolism due to venous intravasation

·        Increased risk of surgical emphysema

Flow rate

This reflect the rate of flow of CO2 though the tubing of insufflator. When veress needle is attached the flow rate should be adjusted for 1 liter per minute. Experiment were performed over animal in which direct I.V. CO2 were administered and it was found that risk of air embolism is less if rate is within 1 liter/minute. At the time of access using veress needle technique sometime veress needle may be inadvertently enter inside a vessel but if the flow rate is 1 liter/minute there is less chance of serious complication. When initial pneumoperitoneum is achieved and canulla is inside abdominal cavity the insufflators flow rate may be set at maximum, to compensate loss of CO2 due to use of suction irrigation instrument. This should be remembered that if insufflator is set to its maximum flow rate then also it will allow flow only if the actual pressure is less than preset pressure otherwise it will not pump any gas. Some surgeon keep initial flow rate with veress needle to 1 liter/minute and as soon as they confirm that gas is going satisfactorily inside the abdominal cavity (Percussion examination and seeing obliteration of liver dullness) then they increases flow rate. No matter how much flow rate you set for veress needle, the eye of normal caliber veress needle can give way CO2 flow at maximum 2.5liter/minute. When the flow of CO2 is more than 7 liter/minute inside the abdominal cavity through canulla, there is always a risk of hypothermia to patient. To avoid hypothermia in all modern microprocessor controlled laproflattor there is electronic heating system which maintains the temperature of CO2.

Total Gas used

This is the fourth indicator of insufflator. Normal size human abdominal cavity need 1.5 liter CO2 to achieve intra-abdominal actual pressure of 12 mm Hg. In some big size abdominal cavity and in multipara patients sometime we need 3 liter of CO2 (rarely 5 to 6 liters) to get desired pressure of 12mm Hg. Whenever there is less or more amount of gas is used to inflate a normal abdominal cavity, surgeon should suspect some error in pneumoperitoneum technique. These errors may be leak or may be pre-peritoneal space creation or extravasations of gas. The detail principles and technique of safe access is discussed in the access technique chapter of this book.

Primary Trocar Insertion:

Trocar and canulla 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.

The disposable cannula has 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.

Steps of Primary trocar insertion

Patient position

Same as of veress needle insertion patient should be placed supine with 10-20 degrees head down.

Site

The same site of veress needle entry should be used for primary trocar insertion. Inferior or superior crease of umbilicus can be used in average built patient and trans-umbilical incision can be used in obese patient. Before starting introduction of trocar surgeon should confirm pneumoperitoneum. After adequate distention of abdominal cavity the actual pressure should be equal to the preset pressure and gas flow should stop. Before starting introduction of trocar the initial 1mm stab puncture wound of skin for veress needle should be extended to 11 mm. It should be remembered that most common cause of forceful entry inside the abdominal cavity with primary trocar is small skin incision. To avoid inadvertent injury of bowel due to forceful uncontrolled entry the incision of skin should not be less than 11mm in size. The skin incision for trocar should be smiling in shape (U shaped) along the crease of umbilicus to get a better cosmetic value. After giving 11mm incision with 11 number blade surgeon should spread fatty tissues with Kelly clamp.

Introduction of primary trocar

Surgeon should hold the trocar in proper way. Head of trocar should rest on thenar eminence middle finger should encircle air inlet and index finger should point toward sharp end.

After holding the trocar properly in hand  full thickness abdominal wall should be lifted by fingers thenar and hypothenar muscles. After creation of pneumoperitoneum lfting of abdominal wall is not easy because it will slip but then also it should be grasped to have some counter force against the pressure exerted by the tip of trocar.

Angle of insertion

Initially angle of insertion for primary trocar should be perpendicular to abdominal wall and once surgeon will fill giving way sensation the trocar should be tilted to 60-70 degree angle.

Confirmation of Entry of primary trocar

·        Audible click if disposable trocar or safety trocar is used

·        Whooshing sound if reusable trocar is used (Gas passes from the small hole at the tip of pyramidal shaped trocar to the head of trocar)

·        Loss of resistance felt both in disposable as well as reusable trocar.

Once the trocar entry in abdominal cavity is conformed canulla is stabilized with left hand and trocar is removed by right hand. After removing trocar canulla pushed slightly further inside the abdominal cavity to prevent coming canulla in pre-peritoneal space with movement of abdominal wall with respiration. Telescope is then immediately inserted and first of all the site just below the entry of primary port is examined.

Sometime there may be few drop of blood found just below the site of entry but these few drop of blood is trickled blood through umbilical wound. If surgeon has any doubt about perforation of bowel or injury to vessel he should evaluate this area again after putting other ports.

Working Ports

Subsequent trocars are inserted under direct vision at locations appropriate for the procedure and to the anatomy of the individual. The “Baseball diamond concept” discussed in next chapter is the most appropriate method to decide the site of introduction of working port  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.

Slipping of Port

Sometimes the port wound becomes bigger than the diameter of cannula and it tends to slip out frequently. In this situation a simple stitch over skin and fixing the cannula with the help of sterile adhesive helps. In paediatric laparoscopic surgery stabilizing the port is necessary.

Non-disposable metal cannula have trumpet or flap valves. The flap valves can be manually opened when introducing or removing an instrument. This avoids damaging delicate instruments like tip of telescope or blunting sharp instruments like aspiration needle and scissors. 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.