The current epidemic of obesity presents gynecologic surgeons with the challenge of safely and successfully performing minimally invasive surgery in women who are morbidly or superobese.

In 2004, the prevalence of a body mass index greater than 40 kg/m² was almost 7.0% in females in the United States (JAMA. 2006 Apr 5;295[13]:1549-55.). Most recently, 8.3% of women were reported to have a BMI greater than 40 (JAMA. 2014 Feb 26;311[8]:806-14.). This is a value that the World Health Organization defines as Class III obesity and that, according to further stratification reported in the surgical literature, includes the categories of morbid obesity (40-44.9), superobesity (greater than 45), and super-superobesity (greater than 60).

As a gynecologic oncologist, I see firsthand the impact of obesity on the risk of multiple gynecologic conditions and female cancers, including endometrial cancer, as well as the benefits of a minimally invasive approach. I frequently perform hysterectomies via the minimally invasive approach to treat precancer and cancer of the uterus in morbidly and superobese women who have significant central adiposity.

MIGS benefits in the obese

In the past 15 years, and particularly in the past decade, evidence that obese patients benefit from laparoscopic surgery compared with traditional laparotomy has increased. I consider minimally invasive surgery the standard of care for women with endometrial cancer, regardless of the BMI.

As Dr. Stacey A. Scheib and her colleagues wrote in a recent review on laparoscopy in the morbidly obese, most of the gynecologic literature comparing laparoscopic surgery with laparotomy in this population is focused on gynecologic oncology because obesity is so strongly associated with endometrial and other cancers in women (J Minim Invasive Gynecol. 2014 Mar-Apr;21[2]:182-95.). In one prospective study of women with clinical stage I endometrial cancer and BMIs between 28 and 60, those who underwent laparoscopic surgery – 40 of 42 women over 2 years – had significantly longer operative times but less operative morbidity, shorter hospital stays, faster recovery and better postsurgical quality of life, compared with women who had undergone laparotomy in the previous 2 years. The control patients also had clinical stage I endometrial cancer and similar BMIs (Gynecol Oncol. 2000 Sep;78[3 Pt 1]:329-35.).

Research comparing robotics and conventional laparoscopy in obese gynecologic surgery patients is limited, and findings are inconsistent. It will remain difficult to compare the two approaches because few surgeons are equally skilled in both approaches and because the learning curve for conventional laparoscopy is so much steeper than for robotics.

I favor the robotic approach for morbidly and superobese patients for its superior visualization and ergonomics.

Patient positioning

It is important to use an operative bed that will accommodate the weight and width of obese patients and enable Trendelenburg positioning of up to 45 degrees. We use a bariatric bed with a 1,000-pound weight limit.

Obese patients are at greater risk for neuromuscular injuries and pressure sores, so careful patient positioning and padding of pressure points is critically important. We have found a surgical bean bag to be much more effective in preventing slippage for the morbidly or superobese patient than is egg-crate foam. The bean bag conforms nicely to the shape of the patient’s back, neck, and arms when it is appropriately desufflated. After desufflation, the bean bag must be well taped onto the operative bed.

I sometimes use shoulder blocks for extra assurance. When used, these braces must be attached to the bean bag and not to the patient.

We typically pad the arms completely with gel pads or foam before the bean bag is desufflated. We also often pad the knees and calves before the legs are placed and secured in stirrups made for the morbidly obese, with the buttocks slightly off the table.

In a review of literature on obesity and laparoscopy outcomes, Dr. Georgine Lamvu and her associates recommended that the arms be tucked in the “military” position, along the length of the body (Am J Obstet Gynecol. 2004 Aug;191[2]:669-74.). To ensure that both arms are properly tucked against the length of the body, we use bed extenders or sleds to widen the bed as necessary.

Abdominal access

I use the open Hasson technique in my obese patients and enter the peritoneum under direct visualization. In patients with high levels of morbid obesity, I have found it helpful to retract the adipose tissue using thin Breisky vaginal retractors. These retractors can hold the adipose tissue away from the fascia to facilitate entry into the abdominal cavity via the open technique.

Utilizing the umbilicus as the initial entry point – often desirable in minimally invasive surgery – is frequently not possible in morbidly obese patients because as BMI increases, the umbilicus migrates toward the pubic bone and away from the aortic bifurcation. In patients who were overweight (BMI greater than 25), Dr. W.W. Hurd and his associates noted a repositioning of the umbilicus below the aortic bifurcation of 2 cm or greater (Obstet Gynecol. 1992 Jul;80[1]:48-51.).

Instead, a supraumbilical or left upper quadrant site for initial entry enables optimal triangulation of trocars and visualization of disease. The trocars must then be placed more lateral and cephalad than in thinner women. In doing so, risk to the inferior epigastric is mitigated. Moreover, longer trocar lengths (150 mm) may be required.

To utilize an umbilical entry, it is imperative that the panniculus be placed cephalad to a position between the two anterior iliac spines (Obstet Gynecol. 1998 Nov;92[5]:869-72.). By doing this, the umbilicus is now repositioned relative to the bifurcation of the aorta similar to the thinner patient. This can either be accomplished using assistants to move the panniculus cephalad or taping the panniculus.

Alternatively, if the Hasson technique is not utilized, a Veress needle (50 mm in length) may be used. Based on MRI and CT visualization, Dr. Hurd has long recommended using a 90-degree angle in the obese population, compared with a 45-degree angle in nonobese women (J Reprod Med. 1991;36[7]:473-6.).

I usually place the patient into a moderate Trendelenburg position before docking the robot and observe the patient’s cardiac and respiratory responses to the induction of anesthesia. Adjustments in the degree of Trendelenburg positioning, the insufflation pressure level, and the ventilation settings can then be made if necessary. Occasionally I will decrease the insufflation pressure from 15 to 12 mm Hg, for instance, to accommodate ventilation needs.

A note from Dr. Charles E. Miller, Master Class Medical Editor

It must be recognized that not all physicians agree with the use of shoulder braces. In a review of literature on brachial plexus injuries in gynecologic surgery during 1980-2012, Dr. Nigel Pereira and his associates identified eight case reports, all of which involved Trendelenburg positioning and seven of which utilized shoulder braces. In their evaluation of the literature, the authors concluded that “the force of the shoulder braces on the clavicle and scapula opposes the force of gravity on the humerus, thereby stretching the brachial plexus and leading to nerve injury. This is particularly exaggerated when the arm is hyperabducted (less than 90 degrees), the head is laterally flexed to the opposite side, or the abducted arm is sagging.”

The authors also point out that longer times spent under general anesthesia (commensurate with increased operating times) increase the risk of brachial plexus injury “by increasing joint mobility (particularly when muscle relaxants are used) because the neighboring bony structure is more likely to compress or impinge on the brachial plexus” (CRSLS e2014.00077. [doi:10.4293/CRSLS.2014.00077]).

More pearls from Dr. Miller

Preoperative care. Prior to surgery it is important to examine a patient’s panniculus closely for evidence of infection. As the area underneath the panniculus receives little oxygen, it is at greater risk for both bacterial and fungal infections. If infection is noted, treatment prior to surgery is strongly recommended. Moreover, as the skin under the panniculus is often times “broken down,” which can compromise healing, lateral incisions should not be made in this area.

Since obese women have more severe comorbidities (such as metabolic syndrome, obstructed sleep apnea, coronary artery disease, poorly controlled hypertension, and a difficult airway) and a greater risk of perioperative complications than women who are not obese, they generally require a more-extensive preoperative work-up and additional perioperative considerations. If the minimally invasive gynecologic surgeon is uncomfortable with evaluation of cardiac and pulmonary status, medical clearance and perioperative consultation with an anesthesiologist prior to surgery is strongly recommended.

Perioperative care. There are no studies in the literature supporting the use of antibiotic prophylaxis prior to surgery despite the increased risk of postoperative wound infection in morbidly obese patients. Increased risk of surgical site infection post abdominal hysterectomy has been noted in women with a BMI greater than 35. Therefore, consideration should be given to the use of prophylactic antibiotics. For patients weighing more than 80 kg, I advise using 2 gm prophylactic cefazolin; increase this to 3 gm in patients that weigh more than 120 kg.

The morbidly obese patient is also at greater risk of deep venous thrombosis, especially when the procedure is lengthy. Sequential compression devices are essential. Moreover, use of such antithrombotic agents as Lovenox [enoxaparin] and heparin should be considered until the patient is ambulating.

Postoperative care. It is imperative to stress the need for extensive pulmonary toilet or hygiene (i.e., coughing and breathing deeply to clear mucus and secretions from the airways) as well as early ambulation. The patient should also be counseled to use pain medication judiciously. And until the patient is mobile, the use of antithrombotic agents, such as Lovenox and heparin, should be continued.

Dr. Ahmed reports that she has no disclosures related to this Master Class. Dr. Miller disclosed that he is a consultant and is on the speakers bureau for Ethicon and Intuitive Surgical, and is a consultant for Covidien. Email Dr. Ahmed and Dr. Miller at obnews@frontlinemedcom.com.

Positioning obese patients for minimally invasive gynecologic surgery