Saturday, December 29, 2007
diagnostic laparoscopy , DR. Alaa Mosbah ,M.D OBS&GYN
Introduction : Diagnostic laparoscopy is indicated in any situation when inspection of the abdomen will help establish a diagnosis and to define subsequent treatment. Patients that are to undergo endoscopic surgery should have a complete pre-operative evaluation prior to scheduling the surgery. The preoperative evaluation often includes laboratory and echographic exams in order to determine the clear indication for surgery. The following text describes the usual operating room set up and procedures for a diagnostic laparoscopy. Positioning of the patient / Anesthesia : The patient is transported to the operating room and general anesthesia performed. Following this, place the patient in modified dorsolithotomy position. This position is most practical for operating and allows easy mobilization of the uterus as well as access for hysteroscopy. Some operating tables may be repositioned intraoperatively, allowing the surgeon to change the angle of the legs. Special care should be taken to avoid nerve injury by mal positioning the patient, particularly along the popliteal fossa and brachial plexus. If any part of the patient is in contact with a metal object, she may be at risk of electrosurgical burns. General anesthesia is preferred for laparoscopy as it provides adequate muscle relaxation and assisted respiration particularly as the patient is in Trendelenburg position. Disinfect the vagina, paying special attention to the umbilicus. Empty the urinary bladder. Some surgeons prefer to leave a Foley catheter in place throughout the procedure. We maintain continuous Foley drainage in selected operations, such as a Burch procedure or hysterectomy. These procedures often require longer operating times and are more likely to result in injury to the bladder. For simpler procedures, we simply empty the bladder at the beginning of the operation. Place a tenaculum on the cervix and insert the uterine cannula. This cannula will allow the uterus to be manipulated and should have the capability to perform chromopertubation. Position of the operating team and equipment : The surgeon must be familiar with the mechanics and operation of each piece of equipment. Prior to anesthetizing the patient the operating team must check that the insufflator is functioning and has an adequate supply of gas, the light source is functioning, and the video equipment is in working order. This will prevent avoidable malfunctions which may result in serious complications and surgical delays. Mobile racks for camera and TV monitor, video-recorder, light-source and insufflator are available and help organize the operating room equipment. The surgeon stands on the left side of the patient, the nurse next to him and the assistant on the opposite side. From here, the surgeon is able to continuously monitor all of the equipment (insufflator, light-source, irrigation system, electric generator). Alternatively, the surgeon and his assistant may both stand to the left of the patient with the video monitor on the opposite side. The TV monitor (1 or 2) should be located so that each member of the operating team may follow the procedure. If there is only one monitor, it is best placed at the feet of the patient. Instruments : To perform a basic diagnostic laparoscopy one must have equipment to create a pneumoperitoneum, light source, video, a cable and telescope, and instruments to manipulate the uterus and adnexea. Distention media : The peritoneal cavity is a potential space which only allows visualization of the pelvic organs with adequate distention. The gases commonly used for laparoscopy are carbon dioxide (CO2) and nitrous oxide (NO2). Carbon dioxide is more readily absorbed, non-toxic, and does not support combustion. The only serious risk is that of hypercarbia which only develops at an absorption rate of greater than 100ml/min. For this reason, patients are generally hyperventilated during surgery. The intra-abdominal pressure should not rise above 15mm Hg, higher pressures will increase the absorption rate and risk of gas embolism. Carbon dioxide embolism has been reported at a rate of 1:10,000 to 1:60,000. Early diagnosis may be made by auscultating the characteristic "mill wheel" murmur. Nitrogen is less readily absorbed by body fluids and may lead to subphrenic discomfort. It is also not flammable and does not support combustion. The risk of embolism is similar to that for carbon dioxide. The surgeon must also choose between a large array of gas insufflating systems, both mechanical and electronic. The electronic system maintains the intra-peritoneal pressure at a constant pre set level. Thus the surgeon may perform the procedure without having to constantly monitor the pressures and volumes. Basic instruments · Veress' needle. · One 10-12 mm trocar to pass the laparoscope. · Two to three 5 mm trocars (through which to pass instruments). · One 10-12 mm trocar for larger instruments. · Uterine manipulator. · Laparoscopic scissors. · Atraumatic grasping forceps. · Smooth forceps designed for grasping the tubes. · Bipolar electrocoagulator. · Mobilizer (if possible with graduations). · High flow irrigation-aspiration system. · CO2 laser coupler (optional) and adequate back-stop device. Instruments for more advanced procedures · Unipolar electrocoagulator. · Two needle holders. · Clip forceps. Minimal equipment required to perform laparoscopy · High luminosity laparoscope with 10 mm trocar. · 400 W light source. · CO2 insufflator automatically regulated for pressure and flow rate. It should enable a high rate of CO2 (at least 6 l/min.). · Video camera and screen. · Irrigation-aspiration system with high flow. · Equipment for bipolar and unipolar electrosurgery. · Endoscopic instruments: scissors, 2 forceps (one atraumatic), bipolar coagulating forceps, clip forceps. · Three secondary trocars 5 mm. · One secondary trocar 10-12 mm. Operating Procedure Pneumoperitoneum Insert the Veress'' needle through a vertical, 1 cm intraumbilical incision. In general a 7cm length is sufficient although a 15cm needle is also available for very obese patients. Prior to insertion the spring mechanism is checked on the needle to help avoid visceral puncture. At this intraumbilical site the abdominal wall is thinnest with no intervening fat and the peritoneum closely underlying the fascia. To insert the Veress' needle the abdominal wall is lifted with one hand and the needle passed through the incision. Intraperitoneal placement is confirmed by injecting 5 ml of saline through the Veress' needle. The solution should flow without resistance and should not return when trying to aspirate. Next, deposit a drop of saline on the external os of the needle. It should fall into the needle hub when negative pressure is created by lifting the anterior abdominal wall. Next, insuffltate carbon dioxide at a low flow rate of 2 liters/minute, allowing the patient to adapt gradually to the pneumoperitoneum. When a pressure of 14 mm of mercury is obtained, place the machine should on automatic flow in order to maintain this pressure. Most machines will automatically adjust the flow rate (usually at a maximum flow of 6 l/min.). In rare cases adhesions or extreme obesity may limit the surgeons ability to use the Veress' needle intraumbilically. If these situations arise, the surgeon may either perform and open laparoscopy or insert the Veress' needle through the posterior vaginal fornix. Placement of trocars After attaining a sufficient pneumoperitoneum, place one 10-12 mm umbilical trocar through the Veress' needle incision. The distal tip of the trocar must be sharp. During insertion of the trocar, compress the upper abdominal wall with the free hand to make the lower abdominal wall tense, giving a firm platform against which to insert the trocar and cannula. Direct the trocar towards the pelvis to avoid injury to major vessels.The trocar should pierce the peritoneal cavity as high as possible to assure a panoramic view. Occasionally, the trocar must be placed above the umbilicus (this must be done under direct laparoscopic visualization through an initial umbilical site). Pass the laparoscope through the trocar sleeve and immediately confirm correct intraperitoneal placement. Standard diagnostic laparoscopes vary in diameter from 5-11mm. The 5mm laparoscope is adequate for inspection but is not sufficient for more complex procedures. The light source is also an essential element. In general the standard 150 watt light source is sufficient only for diagnostic laparoscopy. Complex procedures requires a more powerful light (250-400 watt halogen lamp). Next, place the patient in Trendelenburg position in order to allow for the gravitational effect to move the bowel out of the pelvic cavity. Then insert two or three 5 mm trocars under direct vision at ancillary puncture sites for instruments. These secondary trocars are inserted suprapubically, taking care to avoid the epigastric vessels laterally and the bladder medially. While inserting these ancillary trocars, angle toward the pouch of Douglas while the uterus is held in ante-version. Secondary 8-12 mm, rather than 5 mm trocars, may be useful for some procedures. Collaboration with the anesthetist The pressure of the pneumoperitoneum and the extent of the Trendelenburg position must be adapted to the hemodynamic and respiratory demands of each individual patient. Continued communication and collaboration with the anesthetist throughout the procedure is mandatory. This is extremely important because it may be necessary to reduce the Trendelenburg position, lower the intraabdominal pressure, or even convert to laparotomy at any time during the procedure. Inspection of the abdomen and pelvis It is important to approach the evaluation of the pelvis in a systematic and thorough manner. Upper abdomen Begin the inspection with the upper abdomen. Rotate the laparoscope to view the caecum and appendix, using a probe if necessary. Examine the course of the ascending colon to the hepatic flexure. Examine the right lobe of the liver and gall bladder. Sub-diaphragmatic adhesions may indicate prior pelvic inflammatory disease (Fitz-Hugh-Curtis Syndrome). Avoiding the ligamentum falciparum, the laparoscope is rotated to view the left lobe of the liver and stomach. And finally, rotate the laparoscope around to view the descending colon. Uterus, fallopian tubes Next, examine the pelvic organs starting with the uterus. Note its shape, size, position, and mobility. Noting these characteristics may guide in making the diagnosis of either uterine myomas, adenomyosis, or aberrant Mullerian duct fusion. Look at the anterior cul-de-sac and round ligaments for evidence of endometriosis. Inspect the fallopian tubes entirely with the aid of a probe or forceps. Follow the length of the tube looking for evidence of prior infection or endometriosis. Note the thickness of the wall and mobility of the ampulla. Note all peritubal adhesions, or hydrosalpinxes. In cases of infertility, after completing the inspection of the pelvic organs, proceed with chromopertubation to evaluate tubal patency (see below). A more sophisticated technique for evaluating the fallopian tube is salpingoscopy, for a more detailed examination of the tubal mucosa. Ovaries Complete the inspection of one round ligament, fallopian tube and ovary before continuing on with the opposite side. The ovary is manipulated with a probe or forceps in order to examine its entire surface and evaluate its mobility. Again note any signs of endometriosis or adhesion formation. Uterosacral ligaments Finally, examine both uterosacral ligaments and the pouch of Douglas. For a clear view it may be necessary to aspirate the free fluid. Again, this is a common site for endometriosis and adhesion formation. Chromopertubation Chromopertubation is a basic element of a diagnostic laparoscopy for infertility to assess tubal patency. Inject a dilute solution of methylene blue (1:20 solution) through the cervical cannula. Follow the passage of the liquid through the fallopian tube a verify passage of dye through the fimbria. Closure of abdominal incisions After completing the evaluation of the pelvis or endoscopic procedure, in more advanced cases, the laparoscopy is completed as follows. Remove the ancillary ports, examining the incisions internally for bleeding. Then remove the laparoscope and allow the intra-abdominal gas to escape through the sleeve. Take the patient out of Trendelenburg position in order to optimize the decompression of the pneumoperitoneum. Close the small lower abdominal incisions with non-absorbable suture to be removed in 5-7 days. It is wise to place an absorbable fascial suture in the larger >10 mm umbilical incisions followed by a cutaneous non-absorbable suture. Indication for diagnostic laparoscopy 1. Infertility. This is one of the most common indications for diagnostic laparoscopy. A variety of pertinent diagnosis my be determined at laparoscopy these include: adhesions- evidence of prior pelvic infection Structural abnormalities of the uterus, including congenital developmental abnormalities (such as a bicornuate or unicornuate uterus), and fibroids. Endometriosis Fallopian tube occlusion. A diagnostic laparoscopy may clarify the diagnosis and treatment prior to reconstructive surgery. 2. Chronic pelvic pain. The systematic evaluation of the abdomen and pelvis provided by this relatively benign surgery can provide key diagnostic information in the evaluation of a woman with chronic pelvic pain. In particular, the laparoscopy my reveal adhesions or endometriosis not visible by other diagnostic techniques. 3. Chronic Pelvic Inflammatory Disease (PID). It is essential to carefully inspect the liver and diaphragm when considering this diagnosis. 4. Endometriosis. The appearance of endometriosis varies and it is important that the laparoscopist is aware of the spectrum that one might see during a laparoscopy. Early endometriosis may appear as clear vesicles before progressing to red plaques and eventually black plaques. An intra-operative biopsy will confirm the diagnosis. Indications for an urgent diagnostic laparoscopy 1. Acute Pelvic Inflammatory Disease. If the diagnosis cannot be clearly made by the clinical presentation, a diagnostic laparoscopy may be useful the confirm this diagnosis. 2. Ectopic Pregnancy. Today, a laparoscopy for ectopic pregnancy often not only provides the diagnosis, but also allows for the immediate surgical treatment. 3. Torsion of a tube or ovary. This is often a difficult diagnosis to establish. Echography rarely provides a clear diagnosis. Again laparoscopy can both diagnose and treat this condition. Contra-indications to laparoscopy Absolute contraindications A large abdominal mass such as a fibroid or ovarian cyst An irreducible external hernia. A laparoscopy in this situation could enlarge the hernia sac and make the condition worse. Hypovolemic shock. Medical problems such as cardio-respiratory failure, obstructive airway disease, or a recent myocardial infarction. An inexperienced surgeon or a lack of proper equipment. Relative contraindications Multiple prior abdominal incisions Morbid obesity. The difficulty in creating the pneumoperitoneum may be overcome by introducing the Veress'' needle through the posterior vaginal fornix. Local skin infections may require that the locations for the abdominal incisions be altered. Generalized peritonitis Intestinal obstruction or ileus. This is a relative contra-indication because of the increased risk of bowel perforation upon entry of the Veress'' needle or trocars. Coincidental medical conditions such as ischemic heart disease, blood dyscrasias or coagulopathies. Ancillary instruments Forceps A wide range of forceps are available for laparoscopic use. It is less important to have a wide range of forceps than to have perfected the use of one or two. It is important to have at least one of each, an atraumatic forceps and a forceps with teeth for stronger traction. Scissors Scissors which pass through a 5 mm port are sufficient for general dissection. Microscissors may be preferable for adhesiolysis close to the fimbriae or in other delicate locations. It is important that one of the blades is fixed to allow gentle traction to be applied before cutting. Laser The laser will precisely destroy tissue. Both rigid and flexible systems are available. Sutures and clips Sutures Techniques for tying and applying will be discussed in later chapters. In general there are two suturing techniques that are used in laparoscopic surgery. In the first the knot is tied within the abdomen. In the second the knot is tied extracorporeally. Suturing equipment includes: a needle holder, grasping forceps, knot pusher, and needles which can be passed through a 5 mm port. Ligatures Ligatures are most easily applied by using a prepacked modified Roeder loop introduced through the standard 5mm cannula. Clips and Staples Clips and staples my be invaluable for obtaining hemostasis. Instruments are also available which will apply up to three rows of staples on either side of the line where an incision is to be made. A blade contained within the instrument makes the incision. These instruments are disposable and expensive. Although a wide range of equipment exists for performing laparoscopic surgery, it is important to master the use of the basic instruments and appreciate their full potential before expanding to the use of more complicated devices.