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.

Self-Radiopaque Markers Guiding Physician-Modified Fenestration (S-Fenestration) in Aortic Arch Endovascular Repair

Backgrounds and Objectives: Thoracic endovascular aortic repair (TEVAR) has currently become the “first-line choice” for descending aortic pathologies. For pathologies located at the aortic arch, TEVAR with physician-modified fenestration (PMF) has been gained popularity as an alternative choice. However, stent fenestration is an experience-dependent technique and comes with possible adverse events such as misalignment. This study aims to introduce the self-radiopaque PMF (SF), which uses the radiopaque marker as a guiding indicator.

Methods: This is a single-center retrospective study of 125 patients who underwent the SF-TEVAR in Second Xiangya Hospital from December 2015 to December 2020. Data include basic clinical information and technique records of SF-TEVAR with follow-up results.

Results: According to the SF-TEVAR protocol, we have performed the procedures on 125 patients and obtained an instant success rate of 98.4%. A total of 140 aortic stent-grafts and 44 bridging stents have been implanted in this study. The operation time is 64.6 ± 19.3 min, X-ray exposure time (from first digital subtraction angiography (DSA) to last DSA) is 25.6 ± 14.3 min, and contrast volume is 82.2 ± 22.6 ml. The success rate of PMF alignment is 98.4%. One bailout stent-graft was implanted into the left subclavian artery (LSA) by the chimney technique (0.8%). One fenestration was successfully and immediately corrected after misalignment (0.8%). Large simultaneous fenestration was performed in six patients (4.8%) for the left common carotid artery (LCCA) and LSA and in two patients (1.6%) for IA, LCCA, and LSA. One hundred twenty-two out of 125 patients' LSAs have been kept patent by the technique during the follow-up. The bridging stent group consists of 44 patients who received LSA stents, while the non-bridging stent group includes the other 81 patients. Type I endoleak has occurred in seven patients (5.6%) 1 week after the procedure. During follow-up (23 ± 18 months), survival rate is 95.7% and branch artery patent rate is 97.4%.

Conclusions: The SF-TEVAR technique, which utilizes the radiopaque marker in stent-graft as an indication for PMF in TEVAR, seems a likely safe, effective, and efficient procedure that brings acceptable survival rate and branch artery patency rate. SF-TEVAR serves as a progressive alternative method to keep the branch artery patent in aortic arch endovascular reconstruction.

[Automated Detection of Radiopaque Markers in Chest and Abdomen Radiography]

We aimed to develop a computerized method for the detection of radiopaque markers, such as R and L in chest and abdomen radiography by using the generalized Hough transform and the template matching. To develop the computerized method, we used 200 chest and abdomen images in our institution as training cases. First, two template images for R and L markers were created with the same exposure condition as a chest X-ray. Following various image processing, such as edge detection, thinning and Hough transformed, a look-up table that consisted of distance and direction pairs was built for the generalized Hough transform. All training images were preprocessed with median filter, edge detection, binarization, thinning, back ground removal and labeling. For candidates of markers that were detected as true positive or false positive, their vote and cross-correlation were calculated with the generalized Hough transform. To evaluate this proposed method, a validation test was performed with another database that consisted of 800 chest and abdomen images by use of Mahalanobis distance based on vote and cross-correlation in statistics. The precision of detecting the radiopaque markers for 800 test images was 99.9%. In addition, this method worked out well for some specific images in which markers were overlapped with a human body.