Ultrasonographic appearance of retained surgical sponges and gauzes in the acute postoperative period: a phantom and cadaveric study.

Retained surgical sponges or gauzes (RSS) are an uncommon complication of exploratory laparotomy surgery and pose a clinically significant risk to the patient. The purpose of this two-part, prospective, descriptive study was to describe the previously uncharacterized ultrasonographic appearance of RSS in phantom and cadaveric models of the acute postoperative period (24-48 h). For the first part of the study, a gelatin phantom containing a woven gauze with a radiopaque marker (radiopaque gauze), a woven gauze with no marker (nonradiopaque gauze), and a laparotomy sponge with a radiopaque marker (radiopaque sponge) was evaluated with ultrasonography. For the second part of the study, a total of 23 gauzes and sponges (of the aforementioned three types) were placed within the peritoneal cavity of 20 cadavers in one of three randomized locations during an exploratory laparotomy laboratory. The cadavers were imaged with ultrasonography 17 h later and still images and video clips were reviewed. The retained surgical sponges and gauzes in the gelatin phantom displayed multiple hyperechoic layers and variable degrees of distal acoustic shadowing. In cadavers, 100% (23/23) of the retained surgical sponges and gauzes displayed a single hyperechoic layer of variable thickness and distal acoustic shadowing. In 95.6% (22/23) retained sponges and gauzes, there was a thin hypoechoic layer noted superficially to the hyperechoic layer. An improved understanding of the ultrasonographic appearance of retained sponges or gauzes in the acute postoperative period may assist in the identification of these objects.