Bariatric Surgery Expert’s Testimony Found to Aid Trier of Fact in the Absence of Official Medical Guidelines

Court: United States District Court for the District of Hawaii
Jurisdiction: Federal
Case Name: Mettias v. United States
Citation: 2015 U.S. Dist. LEXIS 4896


The plaintiff, an obese mother, signed up for a surgery program at an army hospital to undergo a procedure called Roux-en Y Gastric Bypass (RYGB) in which a surgeon would staple off the upper portion of her stomach and connect it to the intestine, effectively turning her stomach into an egg-sized pouch. She joined a weight loss program associated with the surgery program and lost 30+ pounds in six months, after which she was evaluated as a surgery candidate. She opted to undergo the surgery after a consultation with the doctor but suffered a multitude of complications, leading to this suit. The plaintiff sued the government for medical negligence and offered a bariatric surgery expert witness to establish the applicable standard of care in order to prove the government had failed to meet such standards.

The Bariatric Surgery Expert Witness

The plaintiff’s bariatric surgery expert witness was a medical doctor licensed to practice medicine in the state of New York since 1986. The expert was board certified in general surgery since 1991 and in surgical critical care since 1992. He was a fellow at the American College of Surgeons as well as a professor of clinical surgery and head of graduate medical education at the Albert Einstein College of Medicine at Yeshiva University in New York. The bariatric surgery expert was the head of the general surgery department of the Beth Israel Medical Center. Here, he served as Chairman of both the Surgical Quality Assurance and the Patient Safety committees. He was also a senior attending surgeon at another hospital.

The bariatric surgery expert referenced the American Society for Metabolic and Bariatric Surgery (ASMBS) and the National Institute of Health (NIH) patient eligibility standards for bariatric surgery when forming his opinion on the applicable standard of care for this case. The expert also utilized his own experience as a surgeon, a high-risk surgery expert (including weight loss surgery), and as a member of multiple editorial boards of gastrointestinal medicine journals.

The bariatric surgery expert claimed that surgical eligibility requirements mandate patients be weighed and their BMIs determined on the day of the operation or at the time of the pre-operative meeting. The expert also stated it is standard for qualifying bariatric surgery patients to undergo and fail a weight loss program under medical supervision.


The government argued that neither of the expert’s claims was endorsed by the actual language of the NIH or ASMBS guidelines and thus the expert’s argument was not backed by the established medical authority.

In light of the bariatric surgery expert’s extensive experience as a physician, and with weight loss surgery in particular, the court was satisfied that he had adequate medical, technological, or other specialized knowledge to aid the trier of fact in interpreting the evidence. The court noted that any complaint related to his lack of specific expertise in the subject matter should only speak “to the weight of his evidence, not to its admissibility,” quoting U.S. v. Little.

The court noted that the guidelines do not include any specific language concerning the duration of BMI measurement or the need for previous weight loss efforts to be professionally monitored. Due to this lack of official vocabulary to explicitly support or refute the expert’s assertions, the court deemed the expert’s credibility to be reliant on his own knowledge and experience as a surgeon, citing United States v. Hankey and Sullivan v. United States Dep’t of the Navy.


The court held it was within the bariatric surgery expert’s role as a medical expert to rely on his substantial professional experience to apply the appropriate professional standards to the facts of the case. The motion to exclude was denied.