Exploratory (Diagnostic) Laparoscopy

Exploratory laparoscopy (also referred to as diagnostic laparoscopy) is a minimally invasive method for the diagnosis of intra-abdominal diseases through direct inspection of intra-abdominal organs. Exploratory laparoscopy also allows tissue biopsy, culture acquisition, and a variety of therapeutic interventions.[1, 2] Laparoscopic ultrasonography (LUS) can also be performed during exploratory laparoscopy to evaluate organs that are not amenable to direct visual inspection.

The advent of laparoscopic surgery represents a landmark in surgery that initiated a shift from the era of open abdominal surgery to the minimally invasive surgery revolution.[3, 4] Today, laparoscopy is the most common and preferred method for addressing a number of routine and complex surgical procedures, such as cholecystectomy, appendectomy, splenectomy, adrenalectomy, and others. Whereas the use of laparoscopic techniques is primarily a relatively recent occurrence, the development of laparoscopy spans three centuries.[5]

The main advantages of diagnostic laparoscopy over traditional open laparotomy are as follows:

• Reduced morbidity
• Decreased postoperative pain
• Shorter hospital stay

Diagnostic laparoscopy is useful for making a definitive clinical diagnosis whenever there is a diagnostic dilemma even after routine diagnostic workup, including patients with nonspecific abdominal pain, hemodynamically stable patients who have sustained blunt or penetrating trauma with suspected intra-abdominal injuries, and critically ill intensive care unit (ICU) patients with suspected intra-abdominal sepsis or pathologies.

Diagnostic laparoscopy is an extremely useful staging tool in patients with intra-abdominal cancers (eg, esophageal, gastric, pancreatic, gallbladder, or bile duct cancer; solitary/resectable liver metastasis; and lymphoma). By enabling accurate staging, diagnostic laparoscopy permits patient selection for curative resection or neoadjuvant chemotherapy while avoiding nontherapeutic laparotomy, which is associated with a delay in the initiation of chemotherapy.

This article provides a comprehensive description of the role of exploratory (diagnostic) laparoscopy) as an alternative to traditional open exploratory laparotomy in the management of certain intra-abdominal conditions.

Acute abdominal pain

Acute abdominal pain is one of the most common indications for an emergency department (ED) visit. In 30-40% of these patients, the etiology of the abdominal pain remains elusive despite laboratory and radiologic investigations. When a diagnosis of persistent acute abdominal pain of less than 7 days' duration remains uncertain after baseline diagnostic and radiologic investigations, this condition is termed nonspecific abdominal pain (NSAP).

Traditionally, NSAP has been treated either with open exploratory laparotomy for conditions the patient was presumed to have or with active observation. Unfortunately, these approaches were often associated with prolonged hospital stays, higher numbers of radiologic imaging studies and laparotomies with negative findings, and patient dissatisfaction if the diagnosis could not be established. This scenario is especially prevalent in pregnant women and obese patients, in whom availability of or access to imaging studies is limited by the gestational age or the patient’s size.[1, 6]

In this setting, diagnostic laparoscopy is the preferred next step in management because it permits the following:

• Visualization of the entire abdominal cavity
• Localization of intra-abdominal pathology
• Acquisition of peritoneal fluid for cultures or cytology
• Ability to irrigate the peritoneal cavity to decrease contamination
• In many cases, specific therapeutic intervention (eg, laparoscopic cholecystectomy, appendectomy, or other curative resection)

As a result of these capabilities, exploratory laparoscopy results in an improved diagnosis rate, as well as reductions in nontherapeutic laparotomies, number of radiologic studies performed, delayed initiation of treatment, and overall length of hospital stay.[7, 8, 9, 10, 11]

The literature on the advantages and efficacy of laparoscopic management for specific intra-abdominal diseases (including acute appendicitis, acute cholecystitis, and several others) is vast, and a full survey is beyond the scope of this review.

Regarding the utility of exploratory laparoscopy for patients with NSAP, a meta-analysis of four randomized control trials (N = 811) comparing exploratory laparoscopy with active observation concluded that early diagnostic laparoscopy was associated with a decreased number of patients discharged without a final diagnosis.[12] Length of stay (LOS) in the hospital and readmission rate were also decreased in the diagnostic laparoscopy group; however, these changes did not reach statistical significance.

In a randomized study involving 522 patients with NSAP who underwent either diagnostic laparoscopy (group 1) or observation (group 2), Morino et al found that early exploratory laparoscopy decreased the number of radiologic investigations (114 in group 1 vs 554 in group 2), the percentage of patients without a clear diagnosis (4.2% vs 34.7%), overall morbidity (1.1% vs 27%), and LOS (3.1 days vs 7.3 days).[13] Eight patients in group 1 required readmission (46 total readmission days), compared with 58 in group 2 (201 total readmission days).

In a nonrandomized prospective study, Golash et al reported on 1320 consecutive patients with acute abdominal pain who underwent diagnostic laparoscopy within 48 hours of admission.[14] A definitive diagnosis was made in 90% of patients after diagnostic laparoscopy, of whom 30% underwent a therapeutic procedure. Diagnostic laparoscopy was found to reduce unnecessary laparotomy and improved diagnostic accuracy in this population.

In summary, diagnostic laparoscopy is ideally suited to patients with NSAP as a means of improving diagnostic accuracy, reducing the numbers of radiologic imaging studies and nontherapeutic laparotomies, and shortening overall LOS.[14, 15]

Trauma

Diagnostic laparoscopy is uniquely useful in the evaluation of hemodynamically stable patients who have sustained blunt or penetrating trauma.[16, 17, 18, 19] It can provide accurate diagnosis of intra-abdominal injuries, thereby reducing nontherapeutic laparotomies and associated complications. In some cases, therapeutic procedures can be performed, depending on local expertise and the extent of additional injuries.

Diagnostic laparoscopy is indicated in the following trauma patients:

• Those in whom there is a high index of suspicion for intra-abdominal injuries after a negative initial diagnostic workup
• Those with penetrating abdominal trauma and a breach of the peritoneum where intra-abdominal organ injury is suspected
• Those with tangential gunshot wounds where the intraperitoneal trajectory is unclear

Diagnostic laparoscopy may also be useful for evaluating diaphragmatic injury in patients with penetrating trauma to the thoracoabdominal region (likely more so than ultrasonography [US] alone[20] ), and mainly for the creation of a transdiaphragmatic pericardial window to diagnose or relieve hemopericardium/cardiac tamponade.[8, 1, 21]

Diagnostic laparoscopy in trauma patients is typically performed with the patient under general anesthesia; however, ED diagnostic laparoscopy with local anesthesia[22] and intravenous (IV) sedation has been reported. Diagnostic laparoscopy is indicated only in hemodynamically stable patients and those patients without a clear indication for a laparotomy, such as evisceration or aspiration/leakage of bile or bowel contents.

Limitations that undermine the universal application of diagnostic laparoscopy in trauma patients include prolonged operating room (OR) time to set up laparoscopic equipment, which may delay therapeutic intervention and the difficulty associated with clear identification of certain injuries, such as bowel injuries and retroperitoneal injuries.[8]

Intensive care

Critically ill patients with suspected intra-abdominal pathology pose a uniquely difficult diagnostic problem. Whereas the need to expedite the diagnosis, rule out intra-abdominal pathology, and gain control of the source is pressing, there are inherent risks in transporting ICU patients who are often unstable and require mechanical ventilator or inotropic support to either radiology or the OR.

Bedside diagnostic laparoscopy, which can be performed within the ICU, often with local anesthesia or IV sedation, is ideal for these patients in that it can expedite the diagnosis, enable therapeutic intervention, and avoid the morbidity of open exploration. Note, however, that not all pathologic conditions are readily identifiable by means of exploratory laparoscopy. Conditions involving the retroperitoneum (including the pancreas, perinephric area, and kidneys) may be missed with exploratory laparoscopy.

That said, exploratory laparoscopy has demonstrated excellent accuracy in the diagnosis of more common causes of ICU-related sepsis, such as ischemic bowel, intra-abdominal abscess, perforated viscus, and acalculous/gangrenous cholecystitis.[8, 1, 23, 24]

The most common indication for diagnostic laparoscopy in the ICU is suspected intra-abdominal pathology in a patient with unexplained sepsis. Other indications include the following:

• Abdominal pain and tenderness in an obtunded or sedated patient that do not pose an obvious indication for a therapeutic intervention (eg, free intra-abdominal air, massive gastrointestinal [GI] bleeding, or  small-bowel obstruction) or cannot be explained by other causes (eg, urinary tract infection, pneumonia, or pleuritis)
• Progressive metabolic acidosis (lactic acidemia) that is not explained by other causes
• Suspected intra-abdominal hypertension that is not attributable to small-bowel obstruction/GI bleeding or bowel obstruction; diagnostic laparoscopy is rarely used in this setting, because it may pose an increased risk of bowel injury during port creation, and pneumoperitoneum itself may exacerbate elevated intra-abdominal pressure ^{[1, 3]}

Although minimally invasive surgery has expanded extensively in recent decades, adaptation of this approach to ICU patients, despite multiple indications, has been reported in relatively few case series. Whereas exploratory laparoscopy in this setting has succeeded in decreasing the number of nontherapeutic laparotomies in 36-95% of patients, mortality has remained unchanged (58-100%), probably as a consequence of patients’ underlying critical illnesses.

In two large published series, Peris et al[24] and Karasakalides et al[25] reported on ICU patients who underwent diagnostic laparoscopy.

In the first series (N = 32),[24] bedside diagnostic laparoscopy was performed after an average ICU stay of 8 days, and the mean procedure time was 40 minutes. Diagnostic laparoscopy identified the source of intra-abdominal pathology in 15 patients, of whom 13 subsequently underwent definitive surgical treatment. A diagnosis of cholecystitis was confirmed in seven cases, of which two were treated with open cholecystectomy and five underwent percutaneous cholecystostomy. The time required for diagnostic laparoscopy was shorter (21.8 ± 7.6 min) than that required for computed tomography (CT) when patient transport was included (38.2 ± 6.2 min).

In the second series, of the 35 ICU patients in whom bedside diagnostic laparoscopy was performed, 20 (57.1%) avoided a negative laparotomy.[25] The remaining patients were found to have an intra-abdominal pathologic condition (eg, acalculous cholecystitis, perforated duodenal ulcer, ischemic colitis, or gallbladder empyema).

Bedside diagnostic laparoscopy may be a practical means of identifying or excluding intra-abdominal pathology in a very ill cohort of the ICU population. It can be performed by using local anesthesia with sedation and may permit therapeutic intervention while avoiding the morbidity of a negative laparotomy in patients who are already ill. Large-scale randomized trials are needed for further validation.

Staging of intra-abdominal cancers

A significant percentage of intra-abdominal cancers prove to be inoperable because of metastatic or locally advanced disease despite a preoperative workup suggesting a potentially resectable disease. Historically, these patients would have undergone morbid negative laparotomies with associated complications and the resultant delay in the initiation of adjuvant or palliative chemotherapy.

Diagnostic laparoscopy for accurate staging of intra-abdominal malignancies is referred to as staging laparoscopy and is performed as a standard part of the staging workup for an increasing number of cancer subtypes.[1, 26, 27, 28, 29] Staging laparoscopy is useful for the evaluation of intra-abdominal malignancy in the following respects:

• Accurate staging of the tumor
• Avoidance of nontherapeutic laparotomy in patients with metastatic diseases
• Means of excluding metastatic disease and obtaining tissue biopsy prior to the initiation of neoadjuvant chemotherapy ^[29]
• Means of obtaining tissue for diagnosis (lymphomas) or performing peritoneal lavage cytology to exclude the presence of occult peritoneal metastasis
• Identification of patients with locally advanced disease (fixed tumor or vascular invasion) when there is no evidence of distant metastasis
• Selection of appropriate palliative treatment in patients with advanced or metastatic disease
• Prior to definitive laparotomy after completion of neoadjuvant chemotherapy to assess treatment response or disease progression
• Assessment of suitability for cytoreductive therapy with hyperthermic intraperitoneal chemotherapy in patients with peritoneal carcinomatosis at the time of surgery ^[30]

Detailed discussion of the utility of staging laparoscopy for individual cancer types is beyond the scope of this article; however, a brief overview is provided below.

Esophageal cancer

Esophageal cancer often presents with locally advanced tumors, as well as lymph node or distant metastases, and is associated with an overall poor prognosis. Data suggest that survival may be improved with preoperative chemotherapy and radiation followed by surgical resection. However, as with other GI malignancies, preoperative imaging may suggest resectable disease, though a significant percentage (20-65%) of esophageal cancers are found to be unresectable at the time of exploration.

Diagnostic laparoscopy is particularly valuable in staging esophageal cancer because it helps identify patients who may or may not benefit from preoperative chemotherapy and thus helps avoid avoid laparotomy or thoracotomy with negative findings.

Laparoscopic placement of feeding tubes can also be performed at the same setting as staging laparoscopy, which can improve the nutritional status of these patients and prevent the need for additional procedures such as percutaneous endoscopic gastrostomy (PEG), which may be technically difficult.[1, 27]

In esophageal cancer, staging laparoscopy has a reported accuracy of 75-80% in identifying peritoneal metastasis with a staging sensitivity and specificity of 64% and 70% as compared with US (40-50%) and CT (45-60%). The utility of diagnostic laparoscopy in esophageal cancer is shown to improve with the addition of LUS and video thoracoscopy.[31]

Gastric cancer

Clinical trials have reported improved survival among gastric cancer patients with tumors (T3-T4N1) who received neoadjuvant chemotherapy prior to definitive surgical resection.[32] In those trials, gastric cancer patients with locally advanced tumor or with lymph node metastases derived survival benefit; however, in the presence of unresectable disease or disseminated metastases, 5-year survival remains poor (< 20%).

It is thus imperative to identify gastric cancer patients who may benefit from neoadjuvant chemotherapy and those with advanced or metastatic tumors who are not candidates for therapeutic laparotomy.[33]  This may be done with diagnostic laparoscopy.[34]

Several investigators reported that diagnostic laparoscopy has an accuracy of 89-100% for staging, identifies occult metastasis or unresectable disease, and avoids nontherapeutic laparotomy in 13-57% of gastric patients despite a negative preoperative imaging workup.[35, 36]

Diagnostic laparoscopy has a uniquely high sensitivity (90-96%) for identifying metastasis to liver, peritoneum, and lymph nodes as compared with either US (23-37%) or CT (28-52%). As in pancreatic cancer, diagnostic laparoscopy combined with LUS further improved identification of liver metastasis, and peritoneal lavage cytology enhanced identification of occult peritoneal metastasis by 10-15%.[36]

Pancreatic adenocarcinoma

Despite advances in preoperative imaging (including CT, endoscopic US [EUS], magnetic resonance imaging [MRI], and positron emission tomography [PET]), 15-40% of patients with pancreatic cancer whose tumors are deemed resectable are found to have unresectable tumors because of local tumor extension or presence of metastasis.

Large tumor size, pancreatic adenocarcinoma as opposed to periampullary cancer or duodenal cancer, body and tail location, and preoperative CA 19-9 serum levels higher than 150 U/mL are associated with a finding of metastatic cancer at the time of staging laparoscopy.[37]

The median sensitivity, specificity, and accuracy of diagnostic laparoscopy in identifying imaging-occult, unresectable pancreatic adenocarcinoma are 94% (range, 93-100%), 88% (range, 80-100%), and 89% (range, 87-98%), respectively.

Laparotomy with negative findings can be avoided in 4-36% of patients, but not in all cases; 5-7% of patients believed to be resectable on the basis of diagnostic laparoscopy findings are found to have unresectable tumors at the time of open exploration, typically attributable to occult vascular invasion, fixed tumors, or presence of lymph node metastasis.[37]

When diagnostic laparoscopy is combined with LUS, the diagnostic accuracy of the procedure increases by 12-14%; however, few surgeons and centers have the skills and equipment to interpret LUS images. Peritoneal lavage cytology can further improve the identification of occult metastasis in 7-15% of patients; however, time constraints may hinder identification, and expert cytopathologists may not be available.[38]

In a study evaluating the potential impact of staging laparoscopy against that of upfront laparotomy in patients with "resectable" pancreatic adenocarcinoma who were found to have metastatic disease on surgical exploration, Sell et al found that patients who underwent staging laparoscopy had a shorter time to chemotherapy and showed improved overall survival in comparison with those who underwent exploration without laparoscopy.[39]

Primary liver tumors

Staging laparoscopy is indicated in patients with primary liver tumors when preoperative imaging suggests likely resectable disease and an adequate hepatic reserve. Although the incidence of peritoneal metastases is uncommon in these patients, diagnostic laparoscopy combined with LUS permits assessment of the entire hepatic parenchyma and allows identification of the size, location, and number of liver tumors, as well as potential vascular invasion.

Diagnostic laparoscopy combined with LUS has a sensitivity of 63-67% for identifying unresectable disease in patients with liver cancer and a nontherapeutic laparotomy avoidance rate of 25-40%. Diagnostic laparoscopy with LUS has a sensitivity of 96-100% for lesions larger than 2 cm compared with a sensitivity of 35-40% for triphasic CT. However, diagnostic laparoscopy can also yield false-negative results in 5-15% of primary liver tumors.[25, 26, 27]

Biliary tract tumors

Staging laparoscopy is indicated for nearly all patients with gallbladder cancer, hilar cholangiocarcinoma, or extrahepatic bile duct tumors without evidence of unresectability or metastatic disease on preoperative imaging.[40, 41] The increased availability of EUS may limit the yield of diagnostic laparoscopy to those with T2 or T3 cholangiocarcinoma; most patients with T1 cancers are resectable.

Diagnostic laparoscopy has diagnostic accuracies of 48-60% and 53-60% for identifying unresectable disease in patients with gallbladder cancer and cholangiocarcinoma, respectively.[25, 26, 27]  The addition of LUS may enhance the overall yield and accuracy of diagnostic laparoscopy in this setting.[42]

Colorectal cancer

Patients with primary colorectal cancer but without evidence of systemic metastases seldom benefit from diagnostic laparoscopy, primarily because of its low yield in identifying occult or subclinical metastasis but also because most patients undergo a colectomy (laparoscopic or open) with curative intent or as palliation for bleeding, obstruction, or perforation.

However, when colorectal cancer presents with isolated liver metastases without evidence of extrahepatic disease, diagnostic laparoscopy with intraoperative US can be extremely useful for the identification of the number and location of hepatic metastases, as well as for ruling out peritoneal or extrahepatic disease. When a staging laparoscopy is performed for this indication, a nontherapeutic laparotomy can be avoided in 25-45% of patients.

As with other GI cancers, diagnostic laparoscopy with LUS has a higher sensitivity and specificity of 98-99% for identifying occult hepatic metastasis and evaluating the portahepatic and celiac lymph nodes.[25, 26, 27]

Lymphoma

Hodgkin lymphoma, or Hodgkin disease, originates in one nodal region/group and spreads to contiguous nodal regions in a typically stepwise manner. The prognosis and treatment of Hodgkin disease are determined by the extent of the disease, the involvement of extranodal lymphatic sites, and the presence of constitutional symptoms. Hodgkin disease was typically staged by means of exploratory laparotomy and biopsy of liver and enlarged lymph nodes followed by splenectomy; however, this procedure is associated with significant morbidity.

With improved radiologic imaging and image-guided biopsy procedures, an open operation for staging lymphomas has become mostly obsolete. However, a needle biopsy is associated with high false-negative rates, and architectural classification of lymphomas cannot be interpreted from tissue obtained on a needle biopsy. The goals of the staging workup for Hodgkin disease are to determine the following:

• Presence of intradiaphragmatic disease
• Presence or absence of splenic and liver involvement

This information is especially relevant in patients with clinical stage I and II Hodgkin disease, in that 25-40% of these patients will be upstaged as a result of this information.[43]

Laparoscopic staging of Hodgkin disease typically consists of splenectomy, wedge biopsy of the liver, and three core needle biopsies of the liver. Lymph node biopsies from the left and right para-aortic and iliac nodes and from the celiac, portahepatic, and mesenteric regions may also be obtained, with all operative sites marked by metallic clips to aid localization during subsequent radiation therapy. LUS may also have a role if hepatic lesions are suspected. Oophoropexy behind the uterus may also be performed to protect it from radiation injury.

In addition, laparoscopy may also have a role in assessing treatment response or when a recurrence is suspected.

Unlike Hodgkin disease, non-Hodgkin lymphoma (NHL) does not spread in a predictable or contiguous fashion. These patients may present with prominent retroperitoneal lymphadenopathy, hypersplenism, or both but without peripheral lymphadenopathy, thus requiring laparoscopic biopsy for diagnosis or splenectomy in case of hypersplenism.

Diagnostic laparoscopy in patients with Hodgkin disease and NHL provides tissue for diagnosis, aids in accurate staging, and prevents the morbidity of unnecessary laparotomy. Compared with percutaneous biopsy, laparoscopy biopsy has superior sensitivity (87% vs 100%), specificity (93% vs 100%), and accuracy (33% vs 83%).[44]

Diagnosis of chronic conditions

Liver diseases

Diagnostic laparoscopy is frequently used to evaluate or obtain biopsy in patients with abnormal liver function test results (liver diseases) after nondiagnostic findings from radiologic investigations. It is particularly useful in patients with liver cirrhosis for establishing histopathologic confirmation, grading severity of illness, and evaluating and performing biopsy on lesions that are difficult to access percutaneously.

Other indications include diffuse liver diseases (related to HIV or hepatitis virus, hepatomegaly of unknown etiology, or portal hypertension) and liver masses (to rule out metastatic cancer, hepatoma, or benign masses).

Exploratory laparoscopy is associated with a 91% success rate for obtaining the correct diagnosis in patients who require laparoscopic liver biopsy and has a sensitivity and specificity of 100% and 97%, respectively. LUS can further improve the accuracy of diagnostic laparoscopy.[1, 45]

Nonpalpable testis (cryptorchidism)

In pediatric patients with nonpalpable testicles, diagnostic laparoscopy offers a minimally invasive alternative to open surgical exploration for locating testicles. Diagnostic laparoscopy is indicated when findings from initial inguinoscrotal exploration are nondiagnostic.

In reported series, diagnostic laparoscopy permitted localization of the nonpalpable testis with 99-100% accuracy, and nontherapeutic laparotomy was avoided in 15-30% of patients. Laparoscopic examination also provides information essential for therapeutic planning, including length and point of entry of the vas deferens, presence of malignant transformation, and status of opposite testis (if undescended). If necessary, therapeutic intervention (orchidectomy or orchidopexy[46] ) can be performed laparoscopically in the same setting.[45]

Chronic pelvic pain and infertility

Chronic pelvic pain, defined as pelvic pain lasting more than 6 months, is a complex disorder with multiple underlying etiologies that range from endometriosis and adhesions to pelvic inflammatory disease (PID).

Diagnostic laparoscopy permits direct visualization of pelvic structures, allowing identification of common etiologies, including endometriosis, adhesions, and ovarian cysts. In published reports, diagnostic laparoscopy has a sensitivity of 78-84% for identifying endometriosis directly; pelvic peritoneal biopsy and peritoneal lavage can further improve the diagnostic yield by 20-25%. Diagnostic laparoscopy is a similarly highly accurate method for evaluating women with PID and has a diagnostic accuracy of 78-92%.[1, 45, 47]

Infertility is one common indication in which diagnostic laparoscopy plays an important role.[48] Diagnostic laparoscopy is often combined with hysterosalpingography to evaluate the patency of fallopian tubes, during which a therapeutic intervention can also be undertaken. Diagnostic laparoscopy has a yield of 21-68% for identifying the cause of infertility.[45]

Patient selection for diagnostic laparoscopy with identification of relative or absolute contraindications is vital to a successful outcome from a laparoscopic procedure.

In addition to a detailed history and meticulous physical examination, special effort should be made to identify a prior history of abdominal surgery, intra-abdominal abscess, perforated appendicitis, or the presence of intra-peritoneal mesh for ventral hernia; these conditions may be associated with substantial adhesions. Laboratory studies, electrocardiography (ECG), and chest radiography should be performed according to the same criteria relevant to any surgical procedure necessitating general anesthesia.[45]

Patients with a history of severe chronic obstructive pulmonary disease (COPD) may require additional studies, such as arterial blood gases and pulmonary function tests. Helium gas may be considered as an alternative insufflant. Severe cardiac dysrhythmias should be evaluated and treated; hypercarbia and the resulting acidosis may have adverse effects on the myocardium by accentuating ischemia.

Absolute contraindications for exploratory laparoscopy include the following:

• Known or obvious indication for therapeutic intervention, such as perforation, peritonitis, known intra-abdominal injury, complications of previous surgery, shock, evisceration, or abdominal wall dehiscence
• Acute intestinal obstruction associated with a massive (>4 cm) bowel dilatation, which may obscure the laparoscopic view and increase the likelihood of bowel injury
• Uncorrected coagulopathy
• A tense or distended abdomen (with suspected intra-abdominal compartment syndrome)
• Trauma with hemodynamic instability or a clear indication of bowel injuries, such as presence of bile or evisceration

Relative contraindications for diagnostic laparoscopy include the following:

• ICU patients who are too ill to tolerate pneumoperitoneum, potential hypercarbia, or general anesthesia
• Infection of anterior abdominal wall ( cellulitis or soft-tissue infection)
• Recent laparotomy (within 4-6 weeks) or extensive adhesions secondary to previous abdominal surgery
• Aortoiliac aneurysmal disease (may be associated with increased risk of vascular rupture)
• Pregnancy (may be associated with injury to gravid uterus or fetal distress)
• Cardiopulmonary compromise
• Morbid obesity

Complication prevention

Complications associated with laparoscopic surgery can be classified as those related to anesthesia and those associated with creation of the pneumoperitoneum or insertion of the trocars and may include the following:

• Anesthesia-related complications
• Extraperitoneal gas insufflation
• Injury to intra-abdominal structures
• Bladder injury
• Pneumothorax/pneumomediastinum
• Gas embolism
• Bowel injury
• Port-site recurrence

Anesthesia-related complications

Although diagnostic laparoscopy is associated with same risk of complications seen with general anesthesia in any open procedure, certain factors related to diagnostic laparoscopy may predispose patients to specific anesthesia complications.

Reduced oxygenation and hypercarbia may happen during diagnostic laparoscopy as a consequence of elevated intra-abdominal pressure. Use of a steep Trendelenburg position may limit excursion of the diaphragm. Absorption of the carbon dioxide used to create pneumoperitoneum can lead to hypercarbia and elevated endotracheal tube carbon dioxide levels.

An improvement in oxygenation and relief of hypercarbia can be achieved by using positive-pressure ventilation, increasing the ventilation rate, and reducing laparoscopic insufflation pressure and the flow of carbon dioxide.[49]

Extraperitoneal gas insufflation

In a closed technique, a blunt-tipped Veress needle is introduced into the peritoneal cavity after the skin incision while the anterior abdominal wall is elevated.

Sometimes, the tip of the Veress needle may be situated in the preperitoneal space. Insufflation of carbon dioxide in this situation leads to extraperitoneal emphysema evidenced by crepitus, artificially elevated abdominal pressure reading, and failure to visualize peritoneal structures, whereas a typical spider-web pattern of preperitoneal fascia is seen upon introduction of the laparoscope. On recognition, stopping carbon dioxide insufflation, removal, and reintroduction of the Veress needle should be performed.

Injury to intra-abdominal structures

Introduction of the Veress needle to create a pneumoperitoneum involves blind insertion of the needle into abdominal cavity. Thus, it may be associated with injury to peritoneal structures. Depending on the location of the port, the structures that have been previously reported to be injured include the following:

• Stomach, liver, or spleen (epigastric ports)
• Small intestine, colon, or omentum (ports in the umbilical region)
• Bladder (pelvic ports; see below)

In addition, the abdominal wall and major intra-abdominal vessels, including the abdominal aorta, iliac arteries, or inferior vena cava (IVC), may also be injured.

To reduce incidence of unintentional organ injuries, it is important to avoid previously scarred regions that can be associated with underlying dense adhesions. Insertion of the Veress needle should be done in a controlled fashion, and the tip of the needle should be directed towards the pelvis.

Certain conditions may predispose patients to injury by the Veress needle, including distention of the GI tract (bowel obstruction) and adhesions of bowel to the anterior abdominal wall. After insertion, the needle should be aspirated and its contents carefully examined; the presence of bile, feculent material, or bright red blood suggests a misplaced needle tip.

Bladder injury

Injury to the urinary bladder may happen during initial insertion of the trocar or during blunt and sharp dissection (with laparoscopic scissors) of suprapubic preperitoneal space. The reported incidence of bladder injury is 0.02-8%, most often following a gynecologic or pelvic surgery.

The first sign of trocar injury to the bladder is visualization of the bulb of a Foley catheter or evidence of pneumaturia or hematuria. The diagnosis of bladder injury can also be confirmed by retrograde instillation of blue dye diluted with saline, which allows rapid identification of cystostomy site. Certain preexisting conditions that may predispose patients to bladder injury include bladder or pelvic anomalies or pathologic conditions, such as prior pelvic or bladder surgery, endometriosis, malignant infiltration, bladder diverticula, or previous radiation.

Postoperatively, if the bladder injury was missed, the patient may develop oliguria and urinary ascites; this may be accompanied by hyponatremia and, rarely, hyperkalemia with mild elevation of serum creatinine as a result of peritoneal absorption of urine. Patients who have been discharged from the hospital because of the minor nature of their laparoscopic procedure may present later with lower abdominal discomfort, abdominal swelling, and fever.

After intraoperative identification of bladder injury, depending on the surgeon's expertise, laparoscopic or open repair should be performed in two layers, as follows:

• Approximation of the mucosal edges with absorbable suture (with care taken not to expose the sutures to the bladder lumen)
• Continuous or interrupted repair of the seromuscular layer

Cystostomy may also be closed by using a laparoscopic stapler or preformed suture loops to encircle and secure the cystostomy. When the bladder injury is diagnosed postoperatively, the nature of bladder drainage (whether extraperitoneal or intraperitoneal) should be assessed. An extraperitoneal bladder injury may be treated through simple placement of an indwelling Foley catheter. Intraperitoneal drainage is an indication for subsequent laparoscopic or open repair. To prevent bladder injury, preoperative placement of a Foley catheter is useful.

Pneumothorax/pneumomediastinum

Carbon dioxide may extend from a correctly induced pneumoperitoneum into the mediastinum along congenital defects or along the great vessels and create pneumomediastinum or pneumothorax. Extensive pneumothorax can lead to tension pneumothorax, which manifests as hypoxia, elevated airway pressure, and difficulty in ventilating with a decrease in oxygen tension (PO2) and an increase in carbon dioxide tension (PCO2).

The pneumomediastinum may cause cardiac embarrassment in the form of reduced venous return, hypotension, and cardiac arrhythmias and is associated with loss of dullness to percussion over the precordium. In this event, carbon dioxide insufflation should be stopped, and the remaining gas must be evacuated. After adequate resuscitation, the procedure can be contemplated.[50]

Gas embolism

An unrecognized incorrect intravascular placement of Veress needle and insufflation of carbon dioxide may result in gas embolism or even death. Gas embolism manifests as acute cardiovascular collapse and is associated with cardiac dysrhythmias, tachycardia, cyanosis, and pulmonary edema.

The diagnosis of gas embolism is usually recognized when the anesthesiologist notices an acute drop in oxygen saturation and an abrupt increase in end-tidal carbon dioxide and is often associated with a “millwheel” murmur in the precordial area. Treatment of gas embolism includes immediate cessation of carbon dioxide insufflation and decompression of pneumoperitoneum.

The patient should be turned into the left lateral decubitus position (ie, with the right side up) to help gas accumulation in the right ventricular apex so as to prevent right ventricular outflow obstruction and further gas embolism. The patient should be hyperventilated with 100% oxygen; if the symptoms persist, a central venous catheter should be inserted with the tip into the right heart, and aspiration of the gas should be performed, though the efficacy of this approach is unproven.[51]

Bowel injury

Injury to a hollow viscus may arise from creation of pneumoperitoneum, insertion of trocars, mechanical injury with laparoscopic instruments, or electrocauterization. Previous surgery and adhesions increase the likelihood of bowel injury, which may range in severity from superficial damage of the serosa to complete penetration into the lumen.

Accordingly, it is always important to inspect the bowel at the axis of insertion of the primary trocar and cannula to ensure that it has not been damaged. If the cannula remains within the bowel, the injury will be obvious by the recognition of mucosal folds. A through-and-through injury may be missed and may only be evidenced by the sight of fecal soiling, a fecal smell when the pneumoperitoneum is released, or the subsequent development of peritonitis.

Management of bowel injury depends on the skill of the surgeon. The traditional treatment is to perform laparotomy and suture the bowel in two layers. A skilled laparoscopic surgeon may perform the repair by means of laparoscopic suturing. The defect should be closed in two layers in such a way as to avoid stricture formation; this should be followed by a copious peritoneal irrigation, and a drain should be inserted into the abdomen. Appropriate antibiotic therapy should be instituted.

Port-site recurrence

Although laparoscopic staging of intra-abdominal cancers is a safe technique associated with a low (1-2%) rate of major morbidity (eg, hemorrhage, visceral perforation, or intra-abdominal infection), there was an initial concern of higher rates of port-site recurrence following staging laparoscopy. Dobronte et al first reported a case of port-site tumor recurrence 2 weeks after laparoscopy in a patient with malignant ascites.[52] Thereafter, multiple authors have expressed concern regarding the potential risk of disseminating disease at the time of pneumoperitoneum.

A number of hypotheses have been suggested to explain port-site implantation, including tumor seeding associated with carbon dioxide pneumoperitoneum in animal studies, tissue manipulation, direct wound contamination, poor surgical technique, or immunologic effects such as changes in host immune responses. However, with improved expertise and use of an impervious barrier bag for organ retrieval, there has been no documentation of increased port-site recurrence following staging laparoscopy as compared with open exploration.

Pearlstone et al, based at MD Anderson Cancer Center, reported the results of diagnostic laparoscopy in 533 patients with intra-abdominal cancer (nongynecologic), of whom 339 had upper GI malignancies.[53] Port-site recurrences were noted in four patients (0.88%), three of whom had advanced disease at the time of initial laparoscopy.

A similar study from Memorial Sloan-Kettering Cancer Center reported on 1650 diagnostic laparoscopic procedures performed among 1548 patients with upper GI malignancies, in whom a total of 4299 trocars were inserted.[54] After a median follow-up of 18 months, port-site recurrence was noted in 13 patients (0.8%). An open operation was performed in 1040 patients, of whom nine (0.9%) developed a wound recurrence.

This latter figure is similar to the 0.8-1% incisional recurrence rate noted in open laparotomies for cancer. The authors concluded that laparoscopic staging appeared safe from an oncologic standpoint because port-site implantation is uncommon, differs little from open surgical incision recurrence, and likely reflects the underlying biologic behavior of the disease rather than the type of surgery.[54]

Although laparoscopic surgery is generally associated with overall decreased pain and morbidity, there remains the potential for serious complications, similar to those associated with standard open incisional surgery.

Patients should understand the inherent risks associated with laparoscopic procedures, namely conversion to open surgery due to hemorrhage, bowel injury, failure to progress, and other complications. Additional complications unique to laparoscopy include fatal gas embolism, problems due to hypercarbia, postoperative crepitus, and pneumothorax, as well as procedure-specific complications such as bowel injury during exploratory (diagnostic) laparoscopy.

Laparoscopic equipment and instrumentation continue to evolve at a rapid speed. With the aim of confining the scope of this article, discussion is limited to the basic equipment necessary to perform diagnostic laparoscopy.

Tools for visualization

The components necessary to create a laparoscopic image include a laparoscope, a video camera, a light source, and a display monitor.

The most commonly used laparoscopes are those with 0º or 30º lenses with a diameter of 10 mm (range, 2.7-12 mm). A fiberoptic light cable transmits light from the light source. Image transmission is provided by a lens system within the laparoscope using the same fiberoptic cable. The transmitted image is processed by the camera system and displayed on a video monitor.

The light source consists of high-intensity halogen, mercury, or xenon vapor bulbs with an output of 250-300 W. Some units are equipped with automatic brightness adjustment capabilities. Digital video recorders and video printers are often used to record or preserve laparoscopic images or procedures.

Larger-diameter laparoscopes provides better optical resolution and enable brighter imaging with improved resolution. A 30º laparoscope is preferred to a 0º laparoscope for most procedures because it provides a wider delineation of the surgical field and allows imaging of relatively inaccessible intra-abdominal regions with only a slight movement of the camera.

Equipment to create pneumoperitoneum

An insufflant system consists of insufflator, tubing, and a chosen gas to obtain the pneumoperitoneum. Insufflation can be achieved through either a closed (Veress needle) or an open (Hasson cannula) method.

Carbon dioxide is the most commonly used insufflant agent because it is very soluble in blood and rapidly expelled by lungs. Moreover, it does not support combustion.

In patients with chronic respiratory disease, carbon dioxide may accumulate in the bloodstream, leading to dangerous hypercapnia. Accordingly, in these patients, other insufflant gases (eg, helium, xenon, argon, krypton, room air, oxygen, and nitrous oxide) are alternatives; however, the potential side effects include poor solubility, increased incidence of air embolism, greater risk of fire (with air and oxygen), and higher cost.

Basic instruments needed to perform diagnostic laparoscopy

Instruments for grasping and dissection include a 5-mm Maryland dissector, blunt-tip dissecting forceps, atraumatic grasping forceps, and L- or J- shaped hook dissector.

Instruments for incising and hemostasis include 5-mm laparoscopic scissors, electrocautery (unipolar or bipolar), and various newer energy devices, such as the LigaSure vessel sealing system (Valleylab, Boulder, CO) or an ultrasonically activated scalpel.

Instruments for clipping and stapling (5 mm or 10 mm; range, 5-12 mm) are useful to prevent or stop bleeding. Various stapling devices (linear cutting vs noncutting, intestinal vs vascular) are also available but usually are not essential to the performance of diagnostic laparoscopy.

Instruments for performing biopsy and specimen retrieval include cup biopsy forceps can for liver biopsy. Depending on the size of the tissue and whether the organ is retrieved intact or after in-situ morecellation, a number of organ entrapment and retrieval systems are available. Although retrieval bags are needed in patients with lymphoma or patients who had a therapeutic resection, direct retrieval of specimens through the 12-mm port without the need for a retrieval bag is feasible in most patients undergoing staging laparoscopy for cancer, liver, lymph node, or peritoneal biopsy.

Instruments for suction and irrigation are necessary to improve visualization and prevent accumulation of blood or irrigation fluid. Most commonly, a disposable battery-powered suction-irrigation setup is used, consisting of 5 L of normal saline solution used as an irrigant and a 5- or 10-mm metal tube used as a laparoscopic suctioning device. However, while the suctioning device is in use, it is important to refrain from direct contact with tissues so as to prevent serosal damage.

Instruments for retraction include laparoscopic retractors, which greatly facilitate exposure by keeping the surrounding structures away from the area of interest. Although they come in various shapes, the one most commonly used for for diagnostic laparoscopy is a liver retractor, which is useful for examining the undersurface of liver, as well as the lesser sac.

Optional equipment includes a laparoscopic ultrasound device, which is useful in patients in whom liver metastasis is suspected for accurately measuring the number, size, and location of metastasis, as well as for ruling out inoperable disease in patients with gallbladder or cholangiocarcinoma.

Laparoscopic procedures can accentuate the risk of developing deep vein thrombosis (DVT) through the following two mechanisms:

• Increased venous pooling secondary to reverse Trendelenburg position (cranial end at higher level than foot end)
• Inferior vena cava (IVC) compression attributable to elevated intra-abdominal pressure

Elastic compression stockings applied to legs can improve venous return but may not be sufficient. For patients at moderate-to-high risk for developing DVT (eg, with morbid obesity, operative duration >30 min, a history of previous DVT or pulmonary embolism [PE], or certain cancers with an increased association with DVT) should receive prophylaxis with fractionated or unfractionated heparin.

For preparing the patient, povidone-iodine solution or any solution that is institutionally approved should be used. In most cases, the area of scrubbing and draping extends from nipple to midthigh. However, this area can be extended in accordance with the underlying pathology. For example, in the case of diagnostic laparoscopy for cancer of the esophagus or esophagogastric junction, the thorax and neck should also be cleaned and draped. In patients with pelvic or urologic malignancies, both the groin and the external genitalia should also be prepared and draped.

Anesthesia

Laparoscopic surgical procedures are most commonly performed with general anesthesia and skeletal muscle relaxation. However, in rare circumstances, such as in trauma and intensive care unit (ICU) patients, local anesthesia with intravenous (IV) sedation has been successfully used.[25]

Appropriate anesthetic techniques along with proper monitoring are obligatory for optimal anesthesia care during laparoscopy. Commonly employed monitoring methods include electrocardiography (ECG), noninvasive arterial pressure monitoring, airway pressure monitoring, pulse oximetry, end-tidal carbon dioxide concentration monitoring, peripheral nerve stimulation, and use of a body temperature probe. End-tidal carbon dioxide can be used as a noninvasive substitute for arterial carbon dioxide tension (PaCO2) in evaluating the adequacy of ventilation during laparoscopic surgery.

In hemodynamically unstable patients and in those with cardiopulmonary dysfunction, careful cardiovascular monitoring and arterial blood gas analysis may be necessary.

Nerve stimulation monitoring helps to ensure adequate muscle paralysis, which is necessary for reducing the intra-abdominal pressure required for adequate abdominal distention.[45]

Positioning

The majority of abdominal laparoscopic procedures are performed with patients in the supine position, whereas the lithotomy position is favored for pelvic pathologies (eg, rectal cancer, gynecologic malignancies, or pelvic conditions).

Both arms are typically tucked to the patient's sides to permit the surgeon and assistant to get closer to the patient. A belt is placed firmly across the pelvis and a foot plate placed against the plantar surfaces to prevent the patient from sliding down if a reverse Trendelenburg position is needed. A Foley catheter is not mandatory but should be used when pelvis-based surgery is performed or a prolonged procedure is anticipated.

To facilitate an unobstructed view, gravity is often used to move the structures and organs away from the area of operative interest. For example, during examination of the liver, stomach, or other proximal GI structures, the patient is placed in a reverse Trendelenburg position with a slight left lateral tilt (right side up). To examine pelvic structures, a Trendelenburg position is used (head at the end of the bed at a lower level than feet).

Placement of equipment

Modern laparoscopic surgery is traditionally performed with the surgeon and the assistant standing on the same side of the table and the monitor and table-mounted instrument holder positioned on the opposite side. The scrub nurse stands on the opposite side of the table from the surgeon, with the instrument table towards the end of the table. This facilitates communication between the surgeon and the scrub nurse and allows instruments to be passed more easily.

A secondary monitor can be positioned anywhere in the room to facilitate viewing by the ancillary operating room staff. The cart or laparoscope system holder, with the monitor for the primary surgeon, typically also houses the insufflators placed near the surgeon’s eye level to allow continuous monitoring of carbon dioxide pressure. The light source, camera controls, and any recording devices are also on this cart.

Before making a skin incision for obtaining the pneumoperitoneum required in exploratory (diagnostic) laparoscopy, the following should be checked:

• Light source is working, along with a camera that is focused and white balanced
• Carbon dioxide tank is full, and an extra tank is available in the room
• Irrigation-aspiration unit is working
• Electrocautery unit is functional
• Insufflation is checked for flow and proper shutoff response to kinking of the tubing
• When closed pneumoperitoneum is planned, a Veress needle is checked for flow and proper tip retraction

Depending on the procedure, the access port is often placed in the infra- or supraumbilical region. However, the initial site of port placement should be chosen according to the suspected pathology and the planned therapeutic procedure, with particular attention to avoiding previous abdominal scars.

The pneumoperitoneum can be achieved by means of either closed or open methods. In the closed method, a 14-gauge Veress needle (disposable or reusable) is used to enter the peritoneal cavity. Before the needle is inserted, it is of critical importance to check patency and appropriate retraction of the tip. After an initial nick on the skin, the abdominal wall is lifted with a firm hand grasp or towel clips, and the Veress needle is inserted through the linea alba and away from previous scars.

Entry into the peritoneal cavity is suggested by a sudden release in resistance and can be confirmed by several methods, including aspiration of the Veress needle or suctioning of a saline droplet placed at the hub of the Veress needle.

Once intraperitoneal position is confirmed, the carbon dioxide insufflation is started. The opening pressure should not be elevated (< 5-6 mm Hg). An elevated initial insufflation pressure may reflect clogging of the Veress needle, a kink in the insufflation tubing, inappropriate placement of the Veress needle tip in preperitoneal space or against omentum, inadequate skeletal muscle relaxation, or, in the worst scenario, the needle lying inside the intra-abdominal organs.

The open or Hasson technique of creating a pneumoperitoneum is accomplished by making a small skin incision and dissecting down to the rectus fascia. Stay sutures are laced with 0 absorbable suture material on either side of the fascia, after which the peritoneum is identified and grasped with Kocher or Allis clamps and opened with scissors. Confirmation of entry into the peritoneal cavity can be achieved with visualization of the omentum or small bowel or by digital palpation of the smooth intra-abdominal structures.

A Hasson port is placed and secured in place with the fascial sutures, and the inner obturator is removed. The stay sutures are also used to close the abdominal wall. The insufflation tubing is attached to the side port of the trocar, and the abdomen is inflated rapidly to 15 mm Hg. Additional ports are placed as necessary for tissue manipulation, biopsy, or therapeutic maneuvers.

After port placement, a detailed examination of the peritoneal cavity is performed.

In patients presenting with acute abdominal pain, depending on the site of suspected pathology, all relevant structures (including gallbladder, appendix, colon, and any other likely affected sites) are grossly examined for signs of inflammation (eg, swelling, erythema, fibrinous exudates, inflammatory adhesions, or formation of phlegm). It is important to note the nature of ascitic fluid (clear vs purulent) to rule out intra-abdominal abscesses. In the presence of an obvious pathology, a therapeutic procedure (laparoscopic or open) can be undertaken simultaneously.

In patients with intra-abdominal malignancy, a systematic examination of the primary tumor site as well as all abdominal viscera and the pelvis is performed to identify gross evidence of metastasis. The primary tumor is assessed to detect direct extension into contiguous organs. If there is evidence of widespread or peritoneal-based disease or liver metastasis or if there is a direct extension of the primary tumor to surrounding structures that renders the tumor unresectable, diagnostic laparoscopy is terminated after confirmatory biopsy specimens are taken.

After initial inspection, additional ports can be placed to further explore the areas of interest or to perform a therapeutic procedure. The number and site of port placements depends upon the anatomic region of interest, as well as the planned procedure.

In general, to achieve a desirable operative dexterity, the ports should be placed to form an equilateral triangle or a diamond, with the camera and the distance to the operative target taken into account. Then, 5- or 10-mm additional ports are placed after incision of the skin under direct visualization to prevent unintended injuries.

After inspection of the peritoneal cavity, a systematic examination of the intra-abdominal organs is performed, starting with the liver. The operating table is placed in reverse Trendelenburg position (20-30º) with 10-15º of left lateral tilt. This maneuver pushes surrounding structures, especially the small bowel and omentum, away from the liver and facilitates hepatic examination. Examination of both surfaces (anterior and posterior) of the left lateral section of the liver is carried out, followed by similar examination of the superior and inferior surfaces of the right hemiliver.

Systematic palpation of liver surfaces to detect small tumors is performed with blunt-tip suction or stone-extracting forceps. The examination of diaphragmatic and posterior surfaces of the liver is accomplished by placing the camera in the right upper quadrant or epigastric port(s). Subsequently, the hepatoduodenal ligament, the hilum of the liver, and the foramen of Winslow are examined. Biopsy of abnormal or enlarged lymph nodes is performed with the cup forceps.

In patients with pancreatic or periampullary tumors, meticulous examination of the angle between the duodenum and the lateral aspect of the common bile duct (CBD) is performed to rule out direct tumor infiltration and hepatic artery encasement.

Subsequently, colonic mesocolon is examined by repositioning the patient in a 10º Trendelenburg position without lateral tilt and retracting the omentum towards the left upper quadrant. This maneuver is further facilitated by elevating the transverse colon, which allows the ligament of Treitz to be identified. Careful visual inspection of the mesocolon is performed, and any suspicious nodules or nodes can be biopsied.

The patient is then returned to a supine position. For the majority of patients with upper gastrointestinal (GI) tumors, this is the limit of the staging laparoscopy. However, in patients with pancreatic cancer, it is important to assess the lesser sac and celiac axis. This maneuver is performed by elevating the left hemiliver and incising the gastrohepatic omentum to gain entrance into the lesser sac.

With an angled or 30º laparoscope, a systematic examination of the anterior aspect of the pancreas, the hepatic artery, and the left gastric artery is performed. The caudate lobe of the liver, the inferior vena cava (IVC), and the celiac axis are also examined. Celiac, portal, perigastric, and hepatogastric nodes are examined and can be biopsied if they appear suspicious.

Standard diagnostic laparoscopy is a two-dimensional modality that permits excellent visualization of the peritoneal structures. However, it is limited by the lack of tactile sensation. The inability to see the undersurface of the organs can limit the utility of laparoscopic staging. Direct palpation of the liver with blunt laparoscopic instruments may be useful. However, identification of small tumors or precise delineation of the anatomic relation of a tumor to adjacent structures is often difficult or impossible.

Laparoscopic ultrasonography (LUS) is an excellent adjunct to traditional laparoscopy and can be rapidly performed. LUS probes (curved- or linear-array technology) with high-frequency (6-10 MHz) performance permit high-resolution images to be obtained and can detect lesions as small as 0.2 cm within the hepatic parenchyma.

Color Doppler assessment can also be performed to allow accurate identification of blood vessels. Though primarily used for assessment of the hepatic parenchyma, LUS has been used extensively for evaluation of the biliary tract and in the staging of upper GI malignancies, by allowing assessment of liver metastases, regional nodal disease, or local vascular involvement.

Nevertheless, the additional value of LUS remains controversial. A number of authors have suggested that LUS provides additional information in only 14-25% of patients during staging procedures, but some authors believe that the yield is much less.[35, 36]

Before the procedure is terminated, a meticulous examination is undertaken to ensure adequate hemostasis and correct instrument and gauze and sponge counts. Ports are removed under direct visualization to ensure that there is no visceral herniation or bleeding. An attempt should be made to decompress the abdominal cavity by expelling the pneumoperitoneum to reduce postoperative shoulder pain. All port sites larger than 5 mm should be closed with an absorbable suture, and the skin is closed with either continuous or interrupted subcuticular sutures.