Laparoscopic Surgery Wa’el AlNa’ssan, MD, FACS. Consultant General

Laparoscopic Surgery Wa’el AlNa’ssan, MD, FACS. Consultant General and Laparoscopic Surgeon King Hussein Medical Center

Laparoscopic surgery Also called minimally invasive surgery (MIS), or keyhole surgery, is a modern surgical technique in which operations in are performed through small incisions (usually 0.2–1.5 cm).

Keyhole surgery makes use of images displayed on TV monitors to magnify the surgical elements.

There are many types of minimally invasive surgery

Laparoscopic Surgery Multiple small incisions. Surgeon and one or tow assistants.

Robotic Surgery Multiple incisions are required for technology such as the "Da Vinci" system, which uses a console located away from the patient. The surgeon uses two PlayStation-type controls to manipulate the devices

Single Incision Laparoscopic Surgery (SILS) In contrast, requiring only a single small incision, uses a single trocar with 3-5 cannulas to introduce the camera and the different types of instruments.

NOTES ( Natural Orifices Transluminal Endoscopic Surgery) or scarless surgery. Transgastric. Transvaginal. Transrectal. Transvisceral.

History It is difficult to credit one individual with the pioneering of the laparoscopic approach.

In 1902, Georg Kelling, performed the first laparoscopic procedure in dogs. in 1910, Hans Christian Jacobaeus of Sweden reported the first laparoscopic operation in humans.

The first publication on diagnostic laparoscopy by Raoul Palmer appeared in the early 1950s. Hans Lindermann and Kurt Semm practised CO2 hysteroscopy during the mid-1970s.

In 1981, Semm, from Germany, performed the first laparoscopic appendectomy. Erich Muhe, a general surgeon from Germany uses Semm’s technique and instruments to perform the first laparoscopic cholecystectomy on September 12 1985.

Insufflator The insufflator is a key element in laparoscopic surgery. An insufflator works as a pressure-controlled closed circuit. Monitoring of intra-abdominal pressure.

An insufflator is necessary to: - create the pneumoperitoneum; - maintain it during the procedure; - control gas pressure within the pneumoperitoneum; - periodically renew the gas.

Other measurements carried out by the insufflator: The total volume of gas delivered to the patient is measured. In the presence of a major leak

Insufflators make it possible to regulate the pressure and thus maintain a stable pneumoperitoneum.

In order to create a working space between the organs and the abdominal wall, a pneumoperitoneum is established. Gas is injected by an insufflator into the peritoneal cavity, causing distension in the abdominal wall.

If excessive pressure develops within the system, then the equipment automatically vents some of the gas reducing the risk of gas embolism.

Many surgeons set a maximum pressure of 12 mm Hg since; above 12 mm Hg, the cardiac ejection volume is significantly reduced. Pneumoperitoneum also aids venous capillary stasis, since internal venous pressure is lower than the pressure inside the abdominal cavity.

It is recommended that maximal pressure is always set below 15 mm Hg and usually limited to 12 mm Hg. In pediatric surgery, the pressure should be in the range of 6 mm Hg. Pneumoperitoneum around 30 mm Hg, occasionally resulted in gas embolism.

Laparoscopy can result in significant heat loss by the patient. Heat loss is proportional to the length of the procedure, but is also affected by gas temperature and humidity. the only effective method of preventing heat loss is to insufflate using humidified gas.

Gas replacement: The composition of the gas in the pneumoperitoneum varies over time. The diffusion capacity of CO2 leads to its progressive elimination due to absorption by the blood and then excretion by respiration. At the same time, the CO2 is replaced by diffusion of the N2O anesthetic gas into the peritoneal cavity. This change in the composition of the gas mixture results in an increased risk of gas embolism as N2O is poorly soluble. There is also the potential risk of explosion due to the large concentration of N2O in the abdomen. Continuous, automatic replacement of CO2 in the pneumoperitoneum prevents these potential complications.

Advantages and disadvantages of different gases:

Air: The use of air has been proposed, but the main disadvantage is its weak diffusion capacity in the blood, making it more hazardous in the event of gas embolism. Its slow elimination from the abdominal cavity also causes prolonged postoperative pain.

Oxygen: Oxygen is contraindicated for creating a pneumoperitoneum because it is explosive. Electrocautery is impossible, and its use has been abandoned.

Nitrous oxide: This gas, widely used in anesthesia. The explosion risk has long been recognized and it is no longer used to maintain the pneumoperitoneum. Even when not used to establish the pneumoperitoneum it slowly diffuses into the abdominal cavity from the circulation and needs to be evacuated.

Helium: This is a non-inflammable, non-toxic and biologically inert gas. It has the advantage when treating pheochromocytomas of limiting the discharge of catecholamines. Nevertheless, because of its weak diffusion capacity, in the event of gas embolism, it can cause vascular occlusion leading to neurological deficits. Its use is not standard for laparoscopies.

Other rare gases: Xenon and Argon have few advantages, other than good hemodynamic stability for xenon, which would allow laparoscopy in patients with severe cardiomyopathy. They are rarely used.

CO2 Cheep. Available. Inert gas. Non combustible non inflammable. Diffuses easily, highly soluble, and is eliminated through respiration. Its solubility limits the risk of gas embolism.

Pathological effect

Cardiovascular System The pneumoperitoneum decreases venous return (preload) and cardiac output; it increases the pulse rate, average arterial pressure, systemic vascular resistance (afterload) and pulmonary resistance. These hemodynamic and cardiovascular changes are produced by the increase in intra-abdominal pressure and stimulation of the vasoactive neurohormonal system (vasopressin and the renin-aldosterone-angiotensin system). These changes are independent of the type of gas used and are well tolerated in patients in good health so long as the intra-abdominal pressure does not exceed 15 mm Hg.

Pulmonary system and gas exchange The use of CO2 for the pneumoperitoneum causes hypercapnia and respiratory acidosis due to CO2 absorption into the systemic circulation from the peritoneal cavity (there is no increase in PaCO2 if another gas is used).

The increase in intra-abdominal pressure caused by the pneumoperitoneum results in an increase in intrathoracic pressure, a decrease in thoracopulmonary compliance and an increase in airways resistance (restrictive syndrome).

The lung bases are compressed due to anesthetic-induced diaphragmatic relaxation and the increase in intra-abdominal pressure. This reduces lung volume and pulmonary compliance, increases the physiological dead space and creates a ventilation-perfusion mismatch. The Trendelenburg position aggravates these effects.

Gas exchange during laparoscopy can be improved with the choice of anesthetic technique and the use of positive end-expiratory pressure (PEEP). During CO2 insufflation, PaCO2 will increase 8-10 mm Hg, with a corresponding reduction in pH, before reaching a plateau at about 15-20 minutes after establishing the pneumoperitoneum. A patient in good health usually compensates for the pulmonary changes caused by the CO2 in the pneumoperitoneum.

Organ Perfusion Intra-abdominal organ perfusion

Renal perfusion The pneumoperitoneum reduces renal perfusion and glomerular filtration rate, which is reflected by a reduction in urine output. Increased intra-abdominal pressure causes direct pressure on the renal parenchyma, as well as on renal arteries and veins. Renal function decreases proportionally to the increase in intra-abdominal pressure.

The pneumoperitoneum also activates the renin-angiotensin system, which causes renal vasoconstriction. An intra-abdominal pressure of <15 mm Hg is of no consequence in patients with normal renal function.

Portal perfusion Circulation in the hepatoportal system diminishes progressively with an increase in intra-abdominal pressure. Hepatic enzyme levels may elevate with prolonged laparoscopy or excessive intra-abdominal pressure.

Splanchnic perfusion Increased intra-abdominal pressure mechanically compresses mesenteric vessels and capillaries, reducing splanchnic microcirculation and disrupting oxygen diffusion to the intra-abdominal organs. Patients in good health compensate for this decreased perfusion.

Immune System metastases at the trocar scar site were reported. This complication can be avoided if certain precautions are taken, which include minimal tumor handling, trocar fixation to avoid disconnection, incision irrigation with an iodine solution and protection of the abdominal wall during extraction of the specimen. At present time, the number of metastases to the wall after laparoscopy is no greater than that observed after laparotomy.

Surgical Complications

Injuries during induction of the pneumoperitoneum: Twenty to forty percent of complications that occur during a laparoscopy occur during creation of the pneumoperitoneum. Although rare (<1% of all laparoscopic procedures), these complications are often serious.

Two techniques have been described for creating the pneumoperitoneum: the closed technique using a Veress needle (1936) and Hasson's open technique (1971). The open technique is preferable due to reduced morbidity associated with its use. Nonetheless, the same type of complications can occur with both techniques.

Vascular injuries Rarer (0.04-0.05%) than visceral lesions, but potentially more dangerous (mortality: 8-17%). Epigastric vessels, followed by those of the greater omentum, are the most often affected. However, any vessel can be injured during insertion of the Veress needle or a trocar.

Visceral injury The small intestine is most often affected, followed by the colon and the liver. The morbidity is usually associated with a failure to recognize that an injury has occurred. If left untreated for the first 24 hours major septic complications develop (frequency: 0.06-0.14%; mortality: up to 20% if the lesion is unrecognized).

Pulmonary, Cardiac and Cerebral Emboli This is a very rare complication (<0.6%), but is potentially lethal. Pulmonary embolism is the most frequent; cases of coronary and cerebral artery emboli have also been described.

There are three mechanisms of gas embolism: A) The most frequent occurs during creation of the pneumoperitoneum and is due to direct puncture of a vessel with the Veress needle or the first trocar. It is important to use a safe technique when inserting trocars and to use low flow during insufflation (<1 L/min) when creating the pneumoperitoneum.

B) Intraoperative injury of a vessel within a parenchymal organ (the liver, for example) can result in a large flow of gas directly into the circulation.

C) Rarely, gas embolism can be caused by excessive intra-abdominal pressure (>20 mm Hg) when using a gas like helium that is only slightly soluble.

2 mL/kg/min of CO2 must be injected into an animal's vein before potentially fatal cardiac problems. Helium, which is only very slightly soluble, is less well tolerated if gas embolism occurs and only 0.1 mL/kg/min is necessary to cause cardiac complications.

To avoid the risk of gas embolism, one must: - Use a safe technique when placing trocars. - Avoid excessive intra-abdominal pressure. - Use a highly soluble gas.

Diagnosis of Embolism Trans-esophageal Doppler echography is the most sensitive means to detect gas embolism. Gas embolism is usually suspected based on:- end-tidal CO2, which results from cardiac output and dead space. A simultaneous in PaO2 increases suspicion of pulmonary embolism. ECG changes are also observed if the embolism is large.

If gas embolism is suspected Insufflation is stopped immediately and the pneumoperitoneum is exsufflated. The patient is placed in Trendelenburg with left lateral tilt to limit gas flow from the right ventricle into the pulmonary circulation.

2. Patient is ventilated with 100% O2 to correct hypoxia. The patient is hyperventilated to counteract the increase in dead space and to increase pulmonary excretion of CO2.

3. If these simple measures are not sufficient, a central venous catheter must be inserted into the pulmonary artery to aspirate the gas.

Usually, the high solubility of CO2 allows rapid reversion of the symptoms of gas embolism without treatment. The elimination of CO2 via the lungs is facilitated by the sharp concentration gradient that exists across the alveoli since the ventilation gas is almost free of CO2.

Diffusion During laparoscopy, CO2 under pressure can diffuse, dissect extraperitoneal tissue, and cause subcutaneous emphysema. this complication is an increase in CO2 absorption leading to an increase in PaCO2 absorption, which is sometimes uncontrollable. This increase in PaCO2 is proportional to the severity of the emphysema.

Any increase in PaCO2 after the first 20 minutes of pneumoperitoneum must cause the surgeon to suspect the development of subcutaneous emphysema. Usually an increase in minute ventilation stabilizes the situation. If this is not the case, insufflation must be momentarily interrupted so that the CO2 can be eliminated.

Pneumothorax Intra-abdominal pressure can open vestigial embryonic peritoneopleural channels and provoke a 'spontaneous' pneumothorax.

This results in an increased airways pressure and PaCO2, and a decreased PaO2 and arterial oxygen saturation. From a hemodynamic standpoint, the pneumothorax increases pulmonary resistance and diminishes cardiac output, which is partially compensated for by a rising tachycardia.

Treatment Treatment consists in using PEEP (5 cm H2O). This is usually sufficient to re-inflate the lung and flush out the CO2 from the pleural cavity, avoiding thoracic drainage and correcting the hemodynamic disturbances.

The following additional measures are also useful: stop N2O administration, increase the fraction of inspired O2 and decrease intra-abdominal pressure. If a radiograph at the end of the procedure demonstrates a persistent pneumothorax, it is usually asymptomatic. Thoracentesis is unnecessary, as the CO2 will be resorbed within 30 minutes, and the pneumothorax will disappear.

It is important to differentiate a CO2 pneumothorax from that resulting from the rupture of emphysematous alveoli caused by positive-pressure ventilation used during laparoscopy. In this case, PEEP will aggravate the situation by reducing cardiac output even further. Air in a pneumothorax will not be eliminated spontaneously like CO2 and thoracic drainage is necessary.

Pneumomediastinum Gas can diffuse via the retroperitoneum or during esophageal dissection near the diaphragm. The problem here is the possible development of subcutaneous emphysema in the face and neck, particularly in the head-up position. This disappears spontaneously when the pneumoperitoneum is stopped and does not require treatment.

Pneumopercardium This rare complication is due to the recannalization of vestigial embryonic peritoneopericardial channels or to a puncture of the pericardial envelope. There are hemodynamic consequences if intra-abdominal pressure is excessive. Generally no symptoms occur at pressure <15 mm Hg.

Excessive Pressure A pressure of <12 mm Hg with an adult in good health is considered safe (<7 mm Hg in children). These changes are partially compensated for by adequate preoperative volume loading. It is recommended to use the lowest intra-abdominal pressure that will result in an adequate exposure of the operative field.

Excessive pressure occurs most frequently when a patient is no longer sufficiently paralyzed and anesthesia is not deep enough.

The rapid introduction into the abdominal cavity of liquid (irrigation, lavage) or of another gas (Argon coagulation) can also cause excessive pressure rises.

Other Complications Bacterial contamination of the patient.

2. Cellular dissemination into the environment.

Pain:- - Deep visceral pain. - Shoulder pain. Nausea/vomiting:- Depends on:- - Type of anesthesia. - The surgery. - Administration of opiates.

5. Respiratory function. Diaphragmatic dysfunction result in alveolar collapse, hypoxia, and work of respiration. laparoscopy remains the surgical technique of choice in patients at high risk for postoperative respiratory complications (obesity, chronic obstructive pulmonary disease).

In Pregnancy No longer an absolute contraindication for laparoscopy. However, its indication remains limited in general to emergency situations such as acute cholecystitis and acute appendicitis. Given the increased risk of abortion during the first trimester and the volume of the uterus during the third trimester, the second trimester is the period with the least risk.

It reduces postoperative discomfort and usage of opiates. A pressure of <10 mm Hg is desirable, to reduce respiratory complications, and hypoperfusion of the uterus. Place the patient in a position that avoids compression of the inferior vena cava by the uterus. Monitor end-tidal CO2, and blood gases closely to ensure adequate elimination of CO2 and avoid fetal acidosis.

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