Anterior mediastinal gossypiboma.

A retained surgical sponge (gossypiboma) is a rare but serious complication of surgery; most cases occur after intra-abdominal surgery. Intrathoracic gossypiboma is extremely rare, with only a handful of reported cases, most of which are associated with pulmonary surgery (1, 2, 3, 4, 5). Although almost all surgical sponges contain a radiopaque marker, usually a barium sulfate filament, detection of a retained sponge can be very difficult, particularly when its presence is not suspected. We present a case of anterior mediastinal gossypiboma following repair of subaortic stenosis in which the sponge marker was mistaken for a sternal suture wire on chest radiographs.

Case report

A 17-year-old man underwent repair of subaortic stenosis with an uneventful early postoperative course. Two weeks following surgery, he developed mild superficial wound dehiscence at the superior margin of the median sternotomy site, accompanied by scant drainage. Postoperative chest radiographs were interpreted as normal (Fig. 1). The patient was treated with antibiotics and dressing changes. Three months following surgery, he returned to the clinic with erythema, pain, swelling, and fluctuance along the superior sternal margin. A contrast-enhanced CT scan of the chest showed a foreign body in the anterior mediastinum with superficial soft-tissue edema, fluid, and gas (Fig. 2). The patient was taken to the operating room for sternal debridement, where a surgical sponge was removed in its entirety, and the subsequent postoperative course was uneventful.

Figure 1

17-year-old male with gossypiboma. Chest radiograph obtained 1 month after repair of subaortic stenosis. A. PA chest radiograph shows irregular configuration of wire at the level of the manubrium (arrow). Note the figure-of-eight configuration of the cephalad-most sternal suture wire (arrowhead) and the ring with twisted-end configuration of the other suture wires. B. The retained sponge is obscured on the lateral chest radiograph due to superimposed soft tissue.

Figure 2

17-year-old male with gossypiboma. Contrast-enhanced CT of the chest. A. A foreign body is present in the anterior mediastinum containing metal (arrow). B. A slightly more cephalad image shows a bubbly focus of low attenuation in the central portion of the mass (arrow).

Discussion

Retained surgical sponge (also known as gossypiboma or textiloma) following thoracic surgery is extremely rare, with only one case reported following cardiac surgery (4). The overall reported incidence of retained foreign body following surgery ranges from 1 in 1,000 to 1 in 10,000, with gossypibomas composing 80% of these. The retained fiber matrix can rapidly incite a local inflammatory response, leading to granulomatous reaction after about a week and local fibrosis after about two weeks. Alternatively, as in this case, an exudative process with abscess formation may occur (3). Clinical symptoms may not develop until later in the postoperative period and are often nonspecific, such as fever and localized pain (4). In a study of risk factors for retained surgical objects, Gawande et al found that 88% of surgical counts were reported as “correct” despite the presence of a retained instrument or sponge (6). Thus, radiology can play a pivotal role in accurate and timely diagnosis.

Radiography is often the initial imaging examination, and it may provide identification of the radiopaque marker. However, CT is superior to radiography in identifying both surgical sponges and their complications (7). One CT finding quite suggestive of retained surgical sponge is a mass with a spongiform pattern containing small gas bubbles. Other findings include a radiopaque marker or a high-density capsule (3). MRI findings include a discrete mass with low T1- and high T2-signal intensity. Wavy, striped, and spotted low-signal-intensity structures contained within the mass on T2-weighted images have also been described (4).

The anterior mediastinal gossypiboma in this case was overlooked on chest radiographs, as its location and radiopaque marker simulated sternal suture wires. Similar misinterpretations can arise in the abdomen when markers simulate calcification or surgical clips (3). While the patient’s initial postoperative presentation was suggestive of only a mild superficial wound infection, delayed healing and persistent drainage raised suspicion of a retained foreign body. With careful evaluation of the chest radiograph, the differences in caliber and configuration of the metallic marker as compared to the sternal suture wires can be appreciated, as sternal suture wires are usually tied in either a figure-of-eight pattern or in a ring with twisted ends.

Conclusion

While a retained surgical sponge is a rare complication of surgery, it is a serious one. Moreover, its presence may not be suspected clinically, as pre- and postoperative sponge counts are routine practice in most institutions. However, the radiologist may be the first to suggest the presence of a retained foreign body. As in this case, the metallic marker in the sponge may mimic a sternal suture wire.