AJR: 'O' shape points to laparoscopic gastric band slippage
Identification of an O-shaped configuration of a laparoscopic adjustable gastric band on radiography for gastric band slippage can potentially aid the radiologist, surgeon or emergency department physician in the early detection of gastric band slippage and appropriate patient triage, based on the results of a study published in the July issue of the American Journal of Roentgenology.

Emphasizing the importance of the O sign detection on radiography by radiologists and clinicians for gastric band slippage, “As laparoscopic adjustable gastric banding is increasingly used, more patients will present to the emergency department with complications of the procedure, particularly complications from band slippage,” wrote the researchers, led by Sabrina Pieroni, MD, from the departments of radiology and surgery at Boston Medical Center in Boston.

A relatively common and serious complication after placement, gastric band slippage occurs when the stomach herniates superiorly to the band and  the weight of the herniated stomach causes the band to tilt along its horizontal axis so that the anterior and posterior sides of the band are no longer superimposed. This results in an O-shaped band rather than the proper rectangle shape. This complication has been found to occur in four to 13 percent of patients, noted the authors.

Between January 2007 and September 2008 at Boston Medical Center, researchers reviewed the imaging studies of 55 consecutive patients who had undergone laparoscopic gastric banding. Of these patients, four cases of gastric band slippage were diagnosed based on an upper gastrointestinal examination at the time of presentation. On the basis of either radiographic findings or clinical presentation, all patients underwent exploratory surgery.

Pieroni and her colleagues determined that an O-shaped configuration of the gastric band was seen on each initial abdominal radiograph of the four patients diagnosed with gastric band slippage. Moreover, given that baseline upper gastrointestinal examinations were available for comparison for each of the four patients, the authors noted, “in each case, the O-shaped configuration of the band was a change from its rectangular appearance when in the proper position.”

The findings of the study suggest that the O shape can be considered a specific sign for gastric band slippage. “Because the consequences of slippage may require acute surgical intervention, it is imperative that the radiologist is familiar with the surgical technique to correctly position the band and the appearances of a gastric band when correctly and incorrectly positioned,” the researchers concluded.