Basic Instruments & Technology.

 

I. Basic Instruments

   Pneumoflator

  The first requirement for laparoscopy is the provision of a safe pneumoperitoneum. The mechanically monitored pneumoflator is adequate for diagnostic laparoscopy and relatively simple operations. It allows continuous flow of carbon dioxide (CO2) with automatic refilling of the abdomen which can be augmented by rapid refill at a rate of 3 l/min under direct visual control. The intra-abdominal pressure and the volume of gas must be kept within safe limits.

   An electronic CO2 pneumoflator should be used when complex operations are being performed. This is fully automatic and simultaneously measures the intra-abdominal and insufflation pressures which can be preset to cut out at a selected level. The gas deficit is also electronically determined and can be replaced at a rate of 6 1/min.

  When performing operative laparoscopy it is safer to use carbon dioxide (CO2) than nitrous oxide (N2O). Carbon dioxide is 20-fold more soluble in blood and body fluids than air or oxygen. However absorption at a rate of over 100ml/min may lead to hypercarbia and cardiac arrhythmia. This can be prevented by hyperventilation and controlled positive pressure respiration. In all cases where CO2 is used, the patients pulse rate and blood pressure and blood gases should be continuously recorded to detect the earliest signs of circulatory or biochemical changes. Carbon dioxide pneumoperitoneum may also cause postoperative pain as a result of formation of hydrocarbonic acid which is irritant to the peritoneum. Nitrous oxide is safer as regards circulatory changes but any advantage in this respect is offset by the fact that it can support combustion.

  The gas is introduced into the abdomen with a spring-loaded, needle originally designed by Veress of Budapest in 1936 for the production of pneumothorax in the treatment of pulmonary tuberculosis. The Veress needle is available in three different lengths. Normally the 7cm needle should be used but longer ones up to 15cm in length are available for obese patients or for introducing the pneumoperitoneum through the posterior fornix.

  The sharp needle point is automatically withdrawn into its sheath by the spring which allows the needle to be used as a probe for lifting organs and palpating their consistency.

   Trocars and Cannulae

  The choice of trocar is debatable. The pyramidal trocar is easier to insert but is more likely to perforate a blood vessel in the abdominal wall. The conical trocar, although safer in that respect, requires a stronger thrust to insert it with consequent risk of accidentally perforating intra-abdominal organs.

  As with all instruments, the trocars tend to become blunt with use. Disposable trocars have become popular in recent years because they are always sharp and so can be introduced with less force. However, they are expensive.

   Laparoscopes

  The development of the rod lens in 1953 by Professor Hopkins of Reading has improved the performance of laparoscopes giving a brighter image with better definition and a wider viewing angle. A 5mm telescope may be satisfactory for standard diagnostic laparoscopy. The 10-11 mm instrument is preferable for video laparoscopy and for operative procedures. The majority of laparoscopists prefer to use an O degree instrument. The 30degree laparoscope was designed to enable the surgeon to see aspects of organs which are hidden from direct view.

The lens system of the laparoscope provides magnification of x2 but this can be increased a further twofold by the addition of an endo-loupe to permit laparoscopic microsurgery. Further magnification may be obtained with the use of video monitoring which, with modern high resolution cameras, allows very accurate definition.

   Light sources

  The standard light source with 150 watt power is satisfactory for diagnostic laparoscopy but, when performing operative laparoscopy or suing closed circuit color television (CCTV), a cold light fountain with 250 watt halogen lamp is necessary. This maintains a constant color temperature and allows automatic variation of the light intensity by the camera. The modern laparoscopist should be trained in video laparoscopy which allows him to work while watching the image on a screen instead of through-the-lens viewing. The light source, video system including video recorder and the pneumoperitoneum apparatus can all be installed in a mobile cart.

   Forceps

  A variety of forceps are available for diagnostic and operative laparoscopy. The majority of forceps now have scissors grips instead of spring-loaded grips. These allow more accurate manipulation and have a stronger grasp. When using spring-loaded forceps the blades are withdrawn into the shaft of the instrument while they close so it is more difficult to apply them accurately. This may lead to tissue trauma especially during fine tubal surgery. Many modern forceps also have a mechanism to lock them firmly on to tissues.
This allows the operator or assistant to exert constant traction during prolonged dissection of tissues. Two or three grasping forceps should be available. One or two should have atraumatic blades and another should have teeth for stronger traction.

   Scissors

  Scissors should be fine enough to allow accurate dissection but strong enough not to be blunted by frequent use. This problem has recently been improved by the introduction of self-sharpening scissors but many of the instruments available still have a limited life span and must be replaced frequently. Some gynecologists prefer hook scissors which are designed to pull the tissues into the blades and facilitate cutting but others prefer straight scissors which may be more accurate in use.
It is important that one of the blades is fixed to allow the scissors to put tension on tissues before cutting them.

  Fine micro scissors are available for performing delicate surgery when the standard ones would be too large.
Larger scissors introduced through an 11 mm diameter cannula may occasionally be necessary to divide strong pedicles. Similar forceps are used to grasp tough tissues. The 11 mm instruments can be introduced through the abdominal wall by enlarging the original incision with a dilating set which increases the diameter of the incision without further cutting.

   Electro-and Thermo coagulation

  Safe and effective control of intraperitoneal bleeding is an essential prerequisite for any form of surgery and in laparoscopic surgery can be achieved in several ways. Bleeding may be prevented by careful recognition of the correct tissue plane and by taking care to cut only in an avascular area. Bleeding from minor vessels is also prevented by the raised intra-abdominal pressure produced by the pneumoperitoneum. When bleeding does occur from small vessels it may also be controlled by using lavage fluid at 40 degree centigrade.
The mainstay of haemostasis, however, is elector-or thermo coagulation. The classic instrument for electro coagulation was the forceps designed by Palmer for use with a monopolar current which he originally described for tubal electro coagulation. Unfortunately the high frequency monopolar current was responsible for a number of complications resulting from accidental burns. First, excessive heat production can occur at the operation site and the heat may be directly transmitted to adjacent organs to cause thermal damage. Second, the current must return from the operation site to the return electrode on its way back to the generator. The pathway taken by the current is unpredictable but is usually along the surface of loops of bowel towards the pelvic side walls. The return plate should be large so that the power density of the current is low at the point of contact with the skin.

However, while high frequency monopolar current should not be used for extensive coagulation, modern micro diathermy instruments provide a safe and effective method of cutting fine adhesion, performing neosalpingostomy or coagulating areas of endometriosis.
In 1972 Frangenheim of Konstanz introduced bipolar electro coagulation which is safer than monopolar current. In this technique the current passes from one blade of the forceps to the other, coagulating the tissues between the blades. It is still possible for burns to be produced from direct transmission of heat to other tissues. Moreover, if two different electrical generators, one monopolar and the other bipolar, are connected simultaneously to the patient, it is possible for the current generated by the bipolar instrument to be attracted to the return plate of the monopolar generator and to cause inadvertent burns to organs distant from the operation site. It is imperative, therefore, that the monopolar generator is always switched off when bipolar current is being used.

The third type of energy used to secure haemostasis is thermo coagulation in which forceps are heated to 120-140oC for a preset time of 20-40 seconds. The proteins in the tissue between the forceps blades are coagulated. This is probably safer but the tissue response is slower than bipolar electro coagulation.

   Laser

  Laser has become a popular surgical tool during the past 11 years. It allows precise tissue destruction with highly predictable results. The type, power and delivery system depend on the tissue reaction required, be it vaporization or coagulation. Both rigid and flexible systems are available for laparoscopic surgery. An operating or standard laparoscope may be used.

The commonest laser in use is the CO2 laser which must be delivered via a rigid system of prisms and lenses. The articulated arm of the laser is connected to the laparoscope via the laser coupler which has a joystick for adjusting the direction of the laser beam, a quick-release attachment for the laparoscope and interchangeable lens housing. Alternatively the laser may be connected to a second-puncture prove which may include a smoke evacuating channel. When CO2 laser is being used it is necessary to have a back-stop to prevent damage to tissues beyond the target organ.
The other lasers in current use, argon, neodymium:yttrium-aluminum-garnet (Nd:YAG)and potassium-titanic-phosphate (KTP) laser may all be delivered along flexible fiberoptic cables increasing their versatility but requiring directional devices on the introducing channel of the laparoscope.
All staff must wear special goggles to prevent eye damage. Some of the risks to operating room staff may be minimized by using video cameras instead of having filters on the lenses.
CO2 laser is valuable for incising tissues but is not an effective coagulant. It is always necessary to have available additional means of securing haemostasis such as thermo-or bipolar electro coagulation.

   Sutures, Clips and Staples

  Haemostasis and tissue apposition may be achieved in laparoscopic surgery by using sutures, clips or fibrin glue. The value of sutures is limited by the difficulty in performing fine surgery when the working distance between the surgeon’s hands and the tissue is 35cm or more. The needle must be strong enough to be held with the laparoscopic needle holder but the finest suture material available for endoscopic surgery is 6/0. It is, therefore, impossible to emulate microsurgical suturing in laparoscopic surgery despite the advantages of magnification and the excellent vision obtained with modern endoscopes.
Nevertheless suturing is necessary in some operations although its use in others is debatable. This is because sutures may produce tiny areas of tissue ischemia which may predispose to the formation of adhesion.
Ligatures are of value when it is unsafe to use thermal energy. In this case an endoscopic ligature may be applied round the pedicle and the knot tightened by pushing down the tip of the applicator. Sutures may be tied intracorporeally or extracorporeally. The latter knots are simply tightened with a knot pusher.

Hemostatic clips ma be applied to control bleeding or to ligate vessels before dividing them.
Staples have now been developed to occlude vessels and simultaneously divide tissues. These are applied with disposable instruments which insert up to three rows of staples in two separate lines. A cutting blade in the applicator then divides the tissues between the rows of staples. This makes division of structures such as the broad ligament rapid and safe.
Tissue glue may be used to cover surfaces to prevent adhesion formation or to reperitonize areas where the peritoneum has been removed or destroyed by laser. Tissue glue may also be used to close defects in the ovary following ovariotomy.

II. Basic Technology

   Position of the patient

   The patient should be anesthetized using muscle relaxants, endotracheal intubation and intermittent positive pressure respiration. The anesthetist should continuously monitor the patient’s heart rate, blood pressure and blood gases. It is common practice to place the patient in a modified lithotomy position with the legs flexed to 45. However, it is better to abduct the legs without flexion. This allows an assistant to manipulate the uterus and does not interfere with the use of ancillary instruments. There should be a 15 degree Trendelenberg tilt to allow the bowel to be lifted out of the pelvic cavity. The tilt may have to be steeper if more complex surgical procedures become necessary. The patient’s buttocks should protrude over the end of the operating table which should have non-slip mattress to prevent her sliding cephalic on the table.

   Preparation for Laparoscopy

  The operating room nurse should have available all the basic laparoscopy instruments and also those for operative laparoscopy and laparotomy. The surgeon should cleanse the abdomen with a suitable antiseptic solution, paying particular attention to the umbilicus. At the same time the assistant should cleanse, catheterize the bladder and apply a tenaculum to the cervix to manipulate the uterus.

   Insertion of Pneumoperitoneum

  The surgeon should first check the patency of the Veress needle and ensure that the sprig mechanism is functioning. A small incision should be made in the base of the umbilicus and the needle inserted while the abdominal wall is lifted with the other hand. This prevents damage to the underlying viscera and the major vessels. The needle should be held by the milled ring and should be heard to give two clicks as it passes through the fascia and then the peritoneum. The insertion should always be at 90 degree to the surface through the deepest part of umbilicus. The abdominal wall is at its thinnest at that point and the peritoneum is firmly applied to it. It will not peel off with pressure from the needle and predispose to an extraperitoneal insufflation of gas. Insertion of the needle at another site may be necessary if there are adhesions beneath the umbilicus but it should be remembered that the abdominal wall at these sites may be thicker and the peritoneum more loosely applied.

The position of the tip of the Veress needle should be checked by the aspiration test. A 20 ml syringe with normal saline is attached to the Veress needle and aspirated to ensure that the needle is not in bowel or major vessel. About 10 ml of saline should then be injected rapidly and aspirated again. If the needle is correctly sited the saline will be distributed between loops of bowel and no fluid will be withdrawn.
Alternatively the test may be performed by attaching an empty syringe to the Veress needle, aspirating to make sure no faeces or blood is withdrawn and then injecting 20ml of air and repeating the aspiration. If the needle is sited correctly, noting will be withdrawn but, if the needle is in the wrong position, gas or brown or red fluid will appear.

 
Transumbilical insertion of the needle may be difficult or dangerous if the patient is grossly obese or has scars on the abdominal wall from previous operations. In this case the pneumoperitoneum may be introduced through the posterior fornix using a tenaculum to pull the cervix forwards which puts the uterosacral ligaments and the floor of the pouch of Douglas on tension.

 

The pneumoperitoneum is formed by introducing 1-2 litres of carbon dioxide (CO2) at a rate of 11/min. Higher flow rates should only be sued under direct vision after the laparoscope has been inserted. When the pneumoperitoneum is complete, the peritoneal cavity should be tested for adhesions using the sounding test. This is performed by attaching an intravenous needle to the 20ml syringe which should now be half filled with saline. The pneumoperitoneum should be explored below the umbilicus at several points. The presence of space is confirmed by the ability to aspirate gas bubbles and its depth may be estimated by the length to which the needle can be inserted and gas aspirated. Only then should the primary trocar and cannula be inserted.

   Insertion of the Laparoscope

  During insertion of the primary trocar and cannula the upper abdominal wall should be compressed by the free hand to make the lower abdominal wall tense. The trocar and cannula may then be safely inserted along a zigzag path using the extended fore finger to prevent sudden and deep penetration. If the line of insertion is straight there may be risk of herniation of omentum of bowel through the incision.
It is always necessary to use secondary portals of entry through which ancillary instruments can be introduced to allow organs to be retraced or lifted so that all their aspects may be examined. The ancillary instrument may be a long Veress needle, a probe or a pair of forceps. The secondary trocar and cannula must always be inserted under direct vision. They may be introduced within the safety triangle whose base is formed by the bladder and whose apex is the umbilicus while the obliterated umbilical arteries form its lateral walls. Alternatively they may be inserted lateral to the artery which should always be identified by direct vision through the laparoscope or by trans illuminating the abdominal wall.

   Inspection of the abdominal organs

  Inspection of the abdominal organs must always be performed in a systematic manner. The inspection should start with cecum and appendix and proceed upwards on the right side to the ascending colon until the hepatic flexure is reached. The right lobe of the liver and gall bladder should now be inspected. It may be necessary to reverse the Trendelenberg tilt to allow gas to flow to the upper abdomen to obtain a clear view of the liver. The telescope should then be withdrawn a little to allow it to pass the ligamentum falciparum and reach the left lobe of the liver. The anterior aspect of the stomach should be inspected but the spleen cannot normally be seen without retracting the stomach which is rarely indicated. Finally, the descending colon should be inspected as far as the sigmoid colon. It should be remembered that there are normally adhesions between the descending colon and the pelvic side wall and, sometimes, also to the left round ligament. These are physiologic and need not be disturbed unless better access to the left adnexa is needed. The diagnosis of diverticular disease may be confirmed by palpating the consistency of the bowel with the probe or forceps. The altered consistency of the bowel is often obvious.

   Inspection of the pelvic organs

  The pelvic organs may be examined when inspection of the upper abdomen is complete. Detailed inspection is only possible by manipulating the uterus to bring all its aspects into view and by using an ancillary probe or forceps to aid the full examination of the fallopian tubes and ovaries. It is impossible to perform a complete examination of the pelvic organs suing a single puncture technique. The examination must be systematic. It is usual to commence with the uterus and proceed in a clockwise direction.

The uterus should first be examined starting with the fundus followed by the anterior and posterior walls. The size and shape of the uterus should be noted as should the presence of intramural or sub serous fibroids and adhesions which may limit uterine mobility.

 

The anterior cul de sac should next be explored. The bladder peritoneum is a frequent site of peritoneal endometriosis and occasionally adhesion of the bladder to the uterus may be seen resulting form previous surgery. The round ligament should next be seen followed by inspection of the tube in its full length form cornu to fimbriae. It is nearly always necessary to lift the tube with a probe or forceps to see the fimbriae. This should always be done as there may be adhesions or phimosis even if the tube is patent. Peritubal adhesions and adhesions between the tube and ovary must be looked for as they may interfere with its motility and result in infertility. Mild adhesions may be lysed with electrosurgery, scissors or laser. If there are more extensive adhesions it may be necessary to investigate tubal morphology further by salpingoscopy to decide on the optimum form of treatment.

 

When the tube has been inspected, attention should turn to the ovary. The ovary may be lifted by a second instrument placed under the round ligament of the ovary or, less commonly, under the infundibulo-pelvic ligament. Detailed inspection of the ovary should also include seeking evidence of its function as well as signs of disease such as endometriosis.

The broad ligament may be the site of endometriosis as may the uterosacral ligaments or the floor of the pouch of Douglas.

The examination should now continue in a clockwise direction to inspect the left side of the pelvis and will be complete when the anterior cul de sac has been reached again. Failure to use a systematic approach such as this is a common cause of significant pathology being missed.

 World Laparoscopy Hospital, Gurgaon, NCR Delhi, www.laparoscopyhospital.com