Laparoscopy

Minimally invasive surgery has truly revolutionized how abdominal procedures are performed. Minimally invasive surgery in the abdomen is performed using a laparoscope. Laparoscopy is derived from two Greek words, laparos = “abdomen” and skopein = “to look or see.” Laparoscopy involves the principle of minimal access in which operations in the abdomen are performed through small incisions compared to larger incisions needed in traditional “open” surgical procedures.

The benefits of minimally invasive surgery include less pain, improved cosmetic results, and quicker return to baseline functionality. Other benefits include lower wound-related complication rates such as infections and hernias. The morbidly obese patient arguably benefits from laparoscopic surgery to an even greater degree than the normal-weight patient. The elements in laparoscopic surgery are the laparoscope, a telescopic lens system that is connected to a video camera and attached to a lighted fiber-optic cable system. Laparoscopes are currently available in several sizes from 2 millimeters in diameter to 10 millimeters. The abdomen is usually insufflated with carbon dioxide gas to create a working space. Carbon dioxide is almost always chosen because it does not support combustion and it is inexpensive, easily available, and rapidly absorbed.

Any operative procedure performed in the morbidly obese patient is inherently more risky than in normal-weight individuals. Specific to abdominal surgery, not only are there technical challenges to operating on the obese individual due to the thickness of the abdominal wall and amount of visceral adiposity, but also obese individuals are prone to a number of severe physiologic derangements that substantially increases their perioperative risk.

The obese patient suffers from a decreased cardiac reserve. Systemic hypertension, so common in the obese patient, can result in left-sided ventricular hypertrophy, cardiomyopathies, and valvular dysfunction. Obesity is strongly associated with the metabolic syndrome, which promotes arteriosclerosis and coronary artery disease. Arrhythmias are also more common in the morbidly obese and may be further aggravated by obstructive sleep apnea.

In the obese, respiratory physiology is altered. Oxygen consumption and carbon dioxide production is increased and the chest wall compliance is reduced. This, in turn, decreases pulmonary functional residual capacity (FRC) and result in the premature airway closure and subsequent ventilation/perfusion mismatch in the lungs. Chronic intraabdominal hypertension secondary to visceral obesity also may lead to decreased FRC. Severe sleep apnea occurs frequently in the morbidly obese patient and can be associated with [Page 422]a number of complications including arrhythmias, hypoxia, pulmonary hypertension, right-sided heart failure, and cor pulmonale (a failure of the right ventricle of the heart). Gastric physiology is also altered; obese patients are more likely to have large gastric volumes, lower gastric pH, and delayed gastric emptying, which increases their risk for gastric aspiration during surgery. Gastroesophageal reflux is very common in the morbidly obese and can induce asthma.

The elevated body mass in the morbidly obese patient undergoing laparoscopic surgery increases the possibility of developing deep venous thrombosis (DVT) due to the high intraabdominal pressure that impairs the return of blood from the legs to the heart. Obesity may also promote the risks for DVT formation directly as a chronic inflammatory condition and indirectly through decreasing mobility.

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