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Proper placement of ports is important to facilitate completion of the laparoscopic procedure. The location of port sites depends on the type of procedure; the primary port should be placed with this in mind. We do not always place the primary port at the umbilicus but rather judge which site is best for the camera or which is the safest site for the primary puncture in a previously operated abdomen. The first laparoscopic port can be positioned anywhere in the abdomen after pneumoperitoneum has been created. The additional or secondary ports should not be placed too close to each other. The optimal pattern of port placement should form an equilateral triangle or a diamond array around the operative field. This “diamond of success” takes into account the optimal working distance from the operative target for each instrument and the telescope (Fig. 4-1). In laparoscopy, the standard instrument length is 30 cm. To produce a 1:1 translation and movement from the surgeon's hands to the operative field, the fulcrum of the instrument should be 15 cm from the target. A similar separation of the two working ports (surgeon's left and right hands) ensures that these two instruments will not be involved in “sword fighting” and that the angle between the two instruments at the target will be optimal (between 60 and 90 degrees). The secondary port site is chosen, and the abdominal wall is transilluminated to avoid large abdominal wall vessels.10,11 The trocar is watched laparoscopically as it enters into the abdomen, and care is taken to avoid injuring the abdominal contents. During the procedure, the area beneath the primary trocar site is inspected for unexpected injuries.
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There is a wide variety of ports, each with different characteristics, available on the market. The bladed trocars cut the abdominal wall fascia during entry. Because the nonbladed trocars do not cut the abdominal wall as much, they make smaller defects in the abdominal wall and may be less prone to hernia formation in the future. The most commonly used bladed ports have a shield that retracts as the blade is pushed through the fascia of the abdominal wall, and then it engages once inside the abdomen. When first introduced to the market, the shields were called safety shields, but they have lost that designation because the shield provides little protection. The nonbladed trocars come in many forms. One nonbladed trocar is used in the Step system (Covidien, Mansfield, MA), a modified Veress needle that locks inside an expandable sheath. Once inside the abdomen, the Veress needle is removed, and a blunt port is passed into the sheath that guides the port by dilating radially.12 The Ethicon nonbladed trocar has a rough edge of plastic that is twisted and pushed through the layers of the abdominal wall. None of these technologies have proven safer than the more economical reusable nonshielded bladed trocar systems made by most instrument companies (Fig. 4-2).
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Important characteristics of a port need to be considered when choosing which port to use. The advantage of a port introduced with a nonbladed trocar is that the abdominal wall defect is smaller, which does not allow gas to leak from the abdomen during the procedure. Because the fascia is not cut, there is a lower risk of port-site hernia, and the fascia of most 10-mm incisions does not have to be closed. Additionally, these ports tend not to slip out of the abdominal wall during manipulation. Other considerations when choosing a port are the size of the external component, the smoothness of entry and exit of the instruments and specimens, and whether an external reducer cap is needed.
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Access or Placement of the First Port
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No single access technique has emerged as the safest and best technique.13,14 The techniques for abdominal access include direct-puncture and an open-access technique.15 The direct-puncture technique can be performed either by direct trocar insertion without pneumoperitoneum or by first obtaining pneumoperitoneum using a Veress needle and then inserting the first trocar directly. The latter technique is performed most commonly in the United States. Each technique has a specific pattern of complications that must be considered when choosing among them.
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The Veress needle access was first described in 1938.16 This technique involves direct insertion of a needle into the peritoneum after lifting the abdominal wall with towel clips or a firm grip. The optimal site for insertion of the Veress needle is through the central scar at the umbilicus. One can make either a vertical skin incision through the umbilicus, hiding the incision in the base, or a curvilinear incision in an infraumbilical or supraumbilical position. Nevertheless, insertion of the Veress needle should be aimed at the central scar, where the layers of the abdominal wall are fused. This does not mean, though, that the first port inserted must be at the umbilicus. Advocates state that the benefits of this technique are the ability to place the initial port anywhere on the abdomen, that it is relatively quick, and that the skin and fascial openings are smaller, which prevents CO2 leakage during the procedure.
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For safe Veress needle insertion, first one must be certain to check the stylet and needle patency, especially when reinserting it after an unsuccessful initial pass. The Veress needle is available either as a reusable or disposable product and comes in two sizes, both long and short. The spring mechanism that pushes the stylet out, thus protecting bowel from the needle, must be tested when using the reusable Veress needle.
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The safest technique requires stabilizing the abdominal wall (we prefer penetrating towel clips in nonobese patients). It is important to have control over the force and depth of insertion of the needle. This is aided by either placing your wrist against the patient's abdomen or using the nondominant hand to support the hand wielding the needle. It is sometimes necessary to raise the operating table to achieve the proper control. One must be mindful of the fact that the most common catastrophic complication from Veress needle insertion is injury to major vessels. The trajectory of the needle should not be angled toward the aorta or iliac vessels (Fig. 4-3).
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After placement of the Veress needle, one should perform an aspiration test by connecting a syringe filled with saline to the top of the Veress needle and aspirate. Aspiration of air, blood, or bile signifies incorrect placement and should prompt serious concern for an unexpected injury. If there is no aspirate, saline should be injected and should flow easily. The saline should flow down the Veress needle into the peritoneal cavity without pressure, a qualitative measure. Removing the plunger from the syringe and watching the saline level drop briskly may achieve a quantitative assessment of patency. If the saline flows slowly or not at all, the needle is likely in the wrong position, that is, up against an intra-abdominal organ, or it is in the preperitoneal space. Alternatively, the tip may be occluded with fat, or the system may have an “air lock.” To test this, inject a little bit of fluid again gently, and retest by removing the plunger and allowing the saline to drop into the abdomen.
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The Veress needle then is connected to the insufflation tubing. The expected initial insufflation pressure, assuming proper placement, should be less than 5–6 mm Hg. Abnormally high insufflation pressure is an indication that something is not right.17 Because the insufflator is usually set to allow a maximum pressure of 15 mm Hg, a value greater than this suggests that the patient is not anesthetized adequately and is contracting his or her abdominal muscles. If the insufflator records a pressure of 15 mm Hg, there are a few explanations. The most ominous cause would be incorrect placement into an intra-abdominal organ. More likely, the Veress needle tip may be against omentum or is in the preperitoneal space. The insufflation line may be occluded at the stopcock, or there may be a kink in the tubing.
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Direct trocar insertion without first establishing pneumoperitoneum is not used as frequently because many surgeons think that it is dangerous given that the bladed trocar must be pushed into the abdomen with significant force to penetrate the abdominal wall. Surgeons unfamiliar with the technique worry about injury to bowel and vessels when using excessive force. There are, however, many surgeons who perform this technique with no increased complication rate, confirming its safety.18–22 Still other surgeons believe that the open-access technique that involves a “minilaparotomy” is the safest.15,23–25
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The open, or Hasson, technique was first described in 1974.15 A 1- to 2-cm skin incision is made at the umbilicus, and the soft tissue is divided to identify the abdominal wall. The fascia and muscles are opened with a knife, and the peritoneum is identified and grasped with Kocher or Allis clamps. A 0-0 absorbable suture is placed through the fascia, and the Hasson port is secured to the fascial sutures. Later, these sutures can be used to close the abdominal wall. The insufflation tubing is attached to the sideport of the trocar, and the abdomen is insufflated rapidly to 15 mm Hg.
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Newer trocars, called optical trocars, allow visualization of the tip of the trocar as it passes through the layers of the abdominal wall (Fig. 4-4). A straight-viewing 0-degree scope is placed inside a clear trocar that is available with and without a bladed tip. Safe introduction of an optical trocar is a skill that requires judgment and experience and can best be learned in patients with no prior surgery after insufflation is established. Success depends on the operator's ability to see each of the layers of tissue, although visualization does not imply safety.26 It is useful for the surgeon to have command of several access techniques because there is no single technique that is best for all circumstances.27
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Access can be the most challenging aspect of the procedure in some patients no matter which technique is used. This is especially true in obese patients. First, the site of the central scar is often judged inaccurately because the umbilicus is in a caudad position owing to the loose panniculus. Additionally, there is an increased distance between the skin and the abdominal wall fascia. The Veress needle may not penetrate the abdominal wall. If an open-access technique is chosen, it may be difficult to expose the abdominal wall through a small incision. Degenerated fascia in obese patients will make the abdominal wall bounce against the needle or finger, making its identification difficult. Raising the skin with penetrating towel clips does not facilitate this exposure and, in fact, distorts the anatomy, making it more difficult to identify the fascia. Sometimes a modified technique described by Vakili and Knight can be helpful.28 This is a combination of open and Veress techniques in which a small skin incision is made in obese patients. Kochers are used to hold the abdominal wall fascia up, and a Veress needle is passed through the abdominal wall.
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Access is also difficult in patients who have had prior surgery through a midline incision. In these patients, it is unsafe to perform the Hasson technique through the midline site because of the potential for adhesions of bowel to the posterior surface of the abdominal wall. Injury can occur when dividing the fascia or when sweeping adhesions away with a finger. It is difficult to perform the open technique at sites other than the umbilicus because of the multiple layers of the abdominal wall. In these patients, we prefer to place the Veress needle in the next safest location, which is the left upper quadrant along the costal margin. One must be certain that the table is flat because the spleen and liver are injured more easily in patients in the reverse Trendelenburg position. One must be certain that the stomach is decompressed with an orogastric tube before inserting the Veress needle in the left upper quadrant. Once insufflation is obtained, a port can be placed into the abdomen away from the previously operated field. We prefer entering with a 5-mm step port followed by a 30-degree 5-mm scope. Other surgeons recommend use of optical trocars in this situation.
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Care should be taken to prevent port-site hernias, which occur in 0.65–2.80% of laparoscopic gastrointestinal operations,29 because they can lead to bowel obstruction, incarceration, and/or Richter's hernias. All defects created with a 10-mm or greater bladed trocar should be closed, although this is not necessary when using some of the newer nonbladed trocars that create smaller fascial defects.30,31 Most 5-mm defects do not require fascial closure in adults, although there are reported cases of hernias at these sites.9,32,33 Because there is always a possibility of formation of a port-site hernia, the smallest possible port always should be used. When a port is manipulated excessively or has to be replaced multiple times, there may be a larger than expected fascial defect that may require closure. Additional recommendations are to place ports lateral to the rectus muscles when possible.34 At the conclusion of the procedure, removal of ports from the abdomen should be observed to be certain that omentum or abdominal contents are not brought up through the abdominal wall.
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Fascial closure can prevent trocar-site hernia.35 A number of port-site closure devices have been developed36 because small laparoscopic incisions make it difficult to close the abdominal wall with round needles. The closure devices function like crochet needles, passing a suture through the abdominal wall on one side of the fascial incision. The suture end is released intra-abdominally under laparoscopic visualization, and the needle is removed. The needle is replaced (without suture) on the other side of the incision, and the free end is secured and pulled back out through the abdominal wall. A knot is then tied that closes the trocar site, as viewed laparoscopically (Fig. 4-5).
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The overall risk of a trocar injury to intra-abdominal structures is estimated to be between 5 in 10,000 and 3 in 1,000.14 Almost all injuries occur during primary trocar insertion. According to Chandler and colleagues,13 the most commonly injured organ is the small bowel (25.4%), followed by the iliac artery (18.5%), colon (12.2%), iliac vein (8.9%), mesenteric vessels (7.3%), and aorta (6.4%). All other organs were injured less than 5% of the time. The mortality from trocar injury is 13%, with 44% owing to major vessel injury, 26% to bowel injury with delayed diagnosis, and 20% to small bowel injury. Major vascular injuries are noticed immediately and require rapid conversion to laparotomy. They are managed by applying pressure when possible to allow the anesthesia team to maintain and correct volume and prepare for rapid blood loss. Then the surgeon gets control of inflow and outflow to permit repair of the injury. Unfortunately, many bowel injuries are not recognized at the time of the procedure, and nearly half are not noticed until more than 24 hours postoperatively. This obviously leads to severe sequelae and may be prevented by careful dissection and inspection at the conclusion of the procedure.