The field of minimally invasive surgery has evolved and grown over the past 3 decades. This was made possible by developments in technology and was fueled by patient demands for less painful operations and quicker postoperative recovery.

Minimally invasive approaches are now widely used for gastrointestinal, bariatric, hernia, and solid organ surgery. It is the surgeon’s responsibility to become familiar with the new set of techniques and instruments, as well as knowing when to apply them and when to convert to an open operation. Furthermore, understanding how to use and troubleshoot the equipment used in these procedures is critical for any surgeon who performs minimally invasive surgery.

Patient Selection

As in all surgery, choosing the right operation for the patient is the first step. Since all laparoscopic surgery of the abdomen requires the use of general anesthesia, the ability to tolerate anesthesia is an absolute requirement. Patients with impaired exercise tolerance or a history of shortness of breath will need a preoperative consultation with a cardiologist or pulmonologist. Patients with severe carbon dioxide (CO₂) retention can be difficult to manage intraoperatively because the use of carbon dioxide for pneumoperitoneum exacerbates the condition. By increasing the minute ventilation and decreasing the CO₂ pneumoperitoneum from 15 to 8 to 10 mm Hg, one can control metabolic acidosis. Rarely, when these measures are ineffective at controlling hypercarbia, we have resorted to using nitrous oxide (N₂O) for peritoneal insufflation. While not suppressing combustion (as does CO₂), N₂O supports combustion no more than air and has been proven safe for laparoscopic use. A single, blind, randomized trial has demonstrated that N₂O pneumoperitoneum is associated with decreased postoperative pain compared with CO₂.¹

When deciding if a patient is a suitable candidate for a laparoscopic procedure, it is important to assess patient or procedure characteristics that will lengthen the operative time sufficiently to nullify the benefits of laparoscopy. If the laparoscopic operation takes substantially longer than the open equivalent or is more risky, then it is not prudent to proceed laparoscopically. A history of a prior open procedure or multiple open procedures can make access to the abdomen difficult and will be discussed in detail later in this chapter. Adhesions and scarring in the surgical field from prior surgery can make laparoscopic surgery very difficult and may require use of many novel dissecting and coagulating tools. Operating on patients with severe obesity is challenging specifically because torque on transabdominal ports leads to surgeon fatigue and diminishes surgical dexterity. In addition, the long distance from the insufflated abdominal wall to the abdominal organs can make laparoscopic surgery a “far reach.” Special long ports and instruments are available to overcome this difficulty.

Inability to obtain an adequate working space makes laparoscopic surgery impossible. This is encountered most commonly in patients with dilation of the intestine from bowel obstruction. Often, laparoscopic lysis of adhesions for distal bowel obstruction is not technically feasible.² Some patients with appendicitis will have sufficient small bowel dilation that laparoscopic access to the right iliac fossa is not possible. Many laparoscopic procedures create working spaces in extraperitoneal locations. An example is the laparoscopic hernia repair usually performed in the anterior preperitoneal space of Retzius; this may require the use of a balloon dissector to create the space followed by low-pressure insufflation. There are fewer physiologic consequences than with a pneumoperitoneum, but CO₂ can spread widely through the soft tissues, causing subcutaneous emphysema.

Patient Positioning

We rely on gravity for retraction of the abdominal contents to provide exposure. Sometimes this requires steep positional changes, and care must be taken to prevent nerve complications or neuropathies after laparoscopic surgery as in open surgery. Patients must be positioned properly at the beginning of the procedure, making certain that all pressure points are padded. Peroneal nerve injury is caused by lateral pressure at the knee and may occur when the table is “airplaned” to the side with a retractor holding the patient in place. Femoral and sciatic neuropathies are similar in that they are due to compression. Padding the retractor arms and securing the patient to the table can prevent these neuropathies.

It is best if the arms can be tucked for most laparoscopic procedures so that the surgeon may move freely up and down the table in order to line up instruments and the target tissue. This is most important for procedures in the pelvis, where the surgeon will want to stand adjacent to the contralateral thorax. However, even with upper abdominal laparoscopy, tucked arms allow more optimal positioning of instrument columns and monitors. If there is a need to extend the arms on arm boards, one must be very careful to avoid a brachial plexus injury that occurs when the arm is extended greater than 90 degrees at the shoulder. Usually, at the start of a procedure, the arm positioning is safe, but it may change as the patient slides down on the table. For this reason, when reverse Trendelenburg is expected, we place footplates at the feet. This prevents sliding on the table and does not cause any discomfort to the patient because it is much like standing. We secure the ankles as well to be sure they do not “twist” during the procedure. There are footplates available for split-leg tables that can be used when operating on the upper abdomen and steep reverse Trendelenburg is needed.

There may be an increased incidence of deep venous thrombosis after laparoscopic surgery that is due to pooling of blood in the venous system of the lower extremities. Venous return is impaired by compression of the iliac veins from the elevated intra-abdominal pressure exerted by the pneumoperitoneum. In addition, the positional effects of placing the patient in a steep reverse Trendelenburg position lead to further distension of the venous system. All patients undergoing laparoscopic procedures in reverse Trendelenburg, even short procedures such as laparoscopic cholecystectomy, should have sequential compression devices placed before the procedure begins, although this does not improve femoral blood flow entirely.³ Patients at high risk for developing deep venous thrombosis should be treated with subcutaneous anticoagulants as either fractionated or unfractionated heparin.⁴ This includes patients undergoing lengthy procedures, patients with malignancy, obese patients, patients with a prior history of deep venous thrombosis or pulmonary embolism, and patients in whom ambulation after surgery will be delayed.⁵

Laparoscopic surgery is associated with a high incidence of postoperative nausea and vomiting. A recent review asserts that serotonin receptor antagonists such as ondansetron (Zofran, GlaxoSmithKline) appear to be the most effective and should be considered for routine prophylaxis.⁶ Another prospective, blinded, randomized trial showed a decrease in postoperative nausea and vomiting when low-dose steroids were given to all patients.⁷ There was no increased infection rate in the group that received steroids. Other preventive measures include ensuring adequate hydration^8,9 and decompression of the stomach with an orogastric tube before the end of the procedure. Intravenous nonsteroidal anti-inflammatory drugs (NSAIDs) such as ketorolac provide superb pain relief and diminish the need for postoperative narcotics, which may help to prevent nausea and vomiting.

Port Placement

SITE SELECTION

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. 6-1). 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 2 working ports (surgeon’s left and right hands) ensures that these 2 instruments will not be involved in “sword fighting” and that the angle between the 2 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.

PORT CHARACTERISTICS

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. 6-2).

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. In addition, 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.

ACCESS OR PLACEMENT OF THE FIRST PORT

No single access technique has emerged as the safest and best technique.^13,14 The techniques for abdominal access include direct-puncture and open-access techniques.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.

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.

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 2 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.

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. 6-3).

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.

The Veress needle then is connected to the insufflation tubing. The expected initial insufflation pressure, assuming proper placement, should be less than 5 to 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.

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

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.

Newer trocars, called optical trocars, allow visualization of the tip of the trocar as it passes through the layers of the abdominal wall (Fig. 6-4). 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

DIFFICULT ACCESS

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.

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.