CHICAGO – Laparoscopic ultrasound was as effective as transabdominal ultrasound for detecting cholelithiasis, and superior at finding gallbladder polyps, based on data from 253 adults undergoing laparoscopic gastric bypass procedures.
Morbidly obese patients are at increased risk for cholelithiasis, with approximately 22%-52% developing the condition, said Dr. Kosisochi M. Obinwanne at the annual clinical congress of the American College of Surgeons.
For surgeons who perform gallbladder surgery separate from the gastric bypass, "it becomes necessary to obtain images of the gallbladder to determine the presence of gallstones," said Dr. Obinwanne of Gundersen Lutheran Health System in La Crosse, Wisc.
"Transabdominal ultrasound is the gold standard for detecting cholelithiasis," he said. However, the increased visceral and subcutaneous fat in patients with morbid obesity can make detection of gallbladder pathology difficult using transabdominal ultrasound (TAU), but laparoscopic ultrasound (LU) has the potential to be as effective as TAU, he noted.
To evaluate the sensitivity and specificity of LU vs. TAU for detecting gallbladder pathology in morbidly obese patients, Dr. Obinwanne and his colleagues conducted a prospective study of 253 patients who underwent laparoscopic gastric bypass over a 6-year period. Their average age was 43 years, average body mass index was 48 kg/m2, and 76% were women.
The patients underwent both TAU and LU during laparoscopic gastric bypass surgery. Certified ultrasonographers performed TAU, and surgeons blinded to the TAU results performed LU, Dr. Obinwanne said.
Overall, LU and TAU identified cholelithiasis in 60 and 61 patients, respectively, said Dr. Obinwanne. The average common bile duct diameter measurement was 3.7 mm with LU and 4.0 mm with TAU.
However, LU found significantly more gallbladder polyps than did TAU (41 vs. 6). The sensitivity and specificity of LU were 90% and 98%, respectively, for gallbladder pathology and 83% and 85%, respectively, for polyps.
"The mean time to complete an LU procedure was 4 minutes," Dr. Obinwanne said.
The study was limited by its small size, but the results suggest that LU is safe, quick, and easy to perform – and thus it’s an alternative to TAU for detecting gallbladder pathology in bariatric surgery patients.
Dr. Obinwanne had no financial conflicts to disclose.