Laparoscopic surgery in the obese: Safe techniques

Entry variables of 3 body types. Obesity increases the distance between skin and fascia, and can increase the distance between fascia and peritoneum. The difficulty of placing the Veress needle or trocar into the peritoneal cavity increases with this distance. Preperitoneal insufflation of gas exacerbates the problem. In addition, dissection to the level of the fascia for an open (Hasson) approach sometimes requires incision extension and increases the risk of postoperative wound infection.

Obesity also changes the relationship of the umbilicus to the aortic bifurcation. Utilizing computed tomography, Hurd et al⁷ demonstrated that the umbilicus migrates caudally in relation to the aortic bifurcation as the BMI increases. In nonobese patients (BMI 30) patients, the umbilicus had a median location 2.4 and 2.9 cm caudal to the aortic bifurcation, respectively. However, in both groups, the umbilicus was directly over the aortic bifurcation in 30% of patients.

The same group of researchers, again using computed tomography, demonstrated that the distance between the umbilicus and peritoneum at a 45° angle from the umbilicus into the pelvis, in both nonobese and overweight patients, was only 2 cm. In obese patients, this distance increased to a median of 12 cm. Hurd et al⁸ also noted that the distance between the umbilicus and the underlying vessels was only 6 cm at a 90° angle in nonobese patients, but averaged 13 cm in obese patients.

To optimize intraperitoneal Veress needle and trocar placement while minimizing risk to the underlying vasculature, Hurd and colleagues recommend a 45° angle from the umbilicus toward the pelvis in nonobese patients and a 90° approach in obese patients. In overweight patients, the approach should range between 45° and 90° (TABLE 1).

TABLE 1

Instrument placement in laparoscopy: Anatomic distances and suggested angles

Gaining intraperitoneal access: Which approach is best?

A number of studies and case series have explored the fundamental difficulty of gaining intraperitoneal access. Pasic et al⁹ retrospectively analyzed outcomes in separate cohorts of obese and nonobese patients, focusing on 4 entry approaches:

• transumbilical open,
  
• transumbilical Veress needle placement,
  
• subcostal Veress needle placement in the midclavicular line of the left upper quadrant, and
  
• transuterine Veress needle placement.
  

In contrast, the Pelosi case series of 67 consecutive obese patients⁶ reported no failures with a transumbilical open approach after realignment of the umbilical access. This entailed assessing the position of the umbilicus in relation to a line drawn between the 2 anterior superior iliac spines. The umbilicus then was repositioned 8 cm above this line in its “anatomical” position prior to initiating open dissection (FIGURE).

After the open trocar was inserted through the fascia and peritoneum and the patient was placed in the Trendelenburg position, the panniculus maintained its orientation. Pelosi and Pelosi concluded that this realignment of the umbilical axis decreases the depth of open dissection and avoids inadvertent placement of a trocar through both sides of the panniculus.

A prospective, randomized study¹⁰ comparing transumbilical and transuterine Veress needle placement in obese patients found the latter approach useful, but recorded a single case of postoperative chlamydial pelvic inflammatory disease. Thus, preoperative testing for sexually transmitted disease is recommended for this approach.

Avoid dogmatic reliance on a single approach

These studies demonstrate a fundamental surgical truism: Sound physiologic and anatomic knowledge, combined with versatility and a grasp of multiple approaches to any problem, are ultimately more successful than unyielding reliance on a single approach. Aim for prudent use of open or closed laparoscopy in a variety of locations, taking into account the patient’s surgical history, distribution of fat, and umbilical displacement.

After achieving pneumoperitoneum

Place a salinefilled spinal needle into the peritoneal cavity on suction to establish abdominal wall thickness. In this way, trocars of appropriate length can be selected.

Some authorities advocate insufflation to a high intraperitoneal pressure (25 to 30mm Hg) prior to placing the initial umbilical trocar if a closed technique is being used.¹¹ This further elevates the abdominal wall and decreases the risk of preperitoneal trocar placement. After successful trocar placement, immediately reduce intraabdominal pressure to 15 mm Hg to avoid pulmonary compromise, excessive catecholamine release, and subcutaneous emphysema.