Intraoperative ultrasound for the colorectal surgeon: current trends and barriers

Contrast-Enhanced Intraoperative Ultrasound Shows Excellent Performance in Improving Intraoperative Decision-Making

BACKGROUND

The aim of this study was to evaluate the performance and the impact of contrast-enhanced intraoperative ultrasound (CE-IOUS) on intraoperative decision-making, as there is still no standardized protocol for its use. Therefore, we retrospectively analyzed multiple CE-IOUS performed in hepato-pancreatic-biliary surgery with respect to pre- and postoperative imaging and histopathological findings.

METHODS

Data of 50 patients who underwent hepato-pancreatic-biliary surgery between 03/2022 and 03/2024 were retrospectively collected. CE-IOUS was performed with a linear 6-9 MHz multifrequency probe connected to a high-resolution device. The ultrasound contrast agent used was a stabilized aqueous suspension of sulphur hexafluoride microbubbles.

RESULTS

In total, all 50 lesions indicated for surgery were correctly identified. In 30 cases, CE-IOUS was used to localize the primary lesion and to define the resection margins. In the remaining 20 cases, CE-IOUS identified an additional lesion. Fifteen of these findings were identified as malignant. In eight of these cases, the additional malignant lesion was subsequently resected. In the remaining seven cases, CE-IOUS again revealed an inoperable situation. In summary, CE-IOUS diagnostics resulted in a high correct classification rate of 95.7%, with positive and negative predictive values of 95.2% and 100.0%, respectively.

CONCLUSIONS

CE-IOUS shows excellent performance in describing intraoperative findings in hepato-pancreatic-biliary surgery, leading to a substantial impact on intraoperative decision-making.

Intraoperative contrast-enhanced ultrasound has an outcome-relevant impact on surgery of primary and metastatic liver lesions

PURPOSE

Complete resection of the affected tissue remains the best curative treatment option for liver-derived tumors and colorectal liver metastases. In addition to preoperative cross-sectional imaging, contrast-enhanced intraoperative ultrasound (CE-IOUS) plays a crucial role in the detection and localization of all liver lesions. However, its exact role is unclear. This study was designed to evaluate the clinical and oncological impact of using CE-IOUS in the surgical treatment of these diseases.

MATERIALS AND METHODS

Over the three-year study period, 206 patients with primary liver tumors and hepatic metastases were enrolled in this prospective, monocentric study to evaluate the impact of CE-IOUS in liver surgery. Secondary outcomes included comparing the sensitivity and specificity of CE-IOUS with existing preoperative imaging modalities and identifying preoperative parameters that could predict a strategic impact of CE-IOUS. In addition, the oncological significance of CE-IOUS was evaluated using a case-cohort design with a minimum follow-up of 18 months.

RESULTS

CE-IOUS findings led to a change in surgical strategy in 34% of cases (n=70/206). The accuracy in cases with a major change could be confirmed histopathologically in 71.4% of cases (n=25/35). The impact could not be predicted using parameters assumed to be clinically relevant. An oncological benefit of a CE-IOUS adapted surgical approach was demonstrated in patients suffering from HCC and colorectal liver metastases.

CONCLUSION

CE-IOUS may significantly increase R0 resection rates and should therefore be used routinely as an additional staging method, especially in complex liver surgery.

Case report: Side-firing intraoperative ultrasound guided endoscopic endonasal resection of a clival chordoma

Clival chordomas are locally invasive midline skull base tumors arising from remnants of the primitive notochord. Intracranial vasculature and cranial nerve involvement of tumors in the paraclival region necessitates image guidance that provides accurate real-time feedback during resection. Several intraoperative image guidance modalities have been introduced as adjuncts to endoscopic endonasal surgery, including stereotactic neuronavigation, intraoperative ultrasound, intraoperative MRI, and intraoperative CT. Gross total resection of chordomas is associated with a lower recurrence rate; therefore, intraoperative imaging may improve long-term outcomes by enhancing the extent of resection. However, among these options, effectiveness and accessibility vary between institutions. We previously published the first use of an end-firing probe in the resection of a clival chordoma. End-firing probes provide a single field of view, primarily limited to depth estimation. In this case report, we discuss the benefits of employing a novel minimally invasive side-firing ultrasound probe as a cost-effective and time-efficient option to navigate the anatomy of the paraclival region and guide endoscopic endonasal resection of a large complex clival chordoma.

Side-firing intraoperative ultrasound applied to resection of pituitary macroadenomas and giant adenomas: A single-center retrospective case-control study

Introduction

Multiple intraoperative navigation and imaging modalities are currently available as an adjunct to endoscopic transsphenoidal resection of pituitary adenomas, including intraoperative CT and MRI, fluorescence guidance, and neuronavigation. However, these imaging techniques have several limitations, including intraoperative tissue shift, lack of availability in some centers, and the increased cost and time associated with their use. The side-firing intraoperative ultrasound (IOUS) probe is a relatively new technology in endoscopic endonasal surgery that may help overcome these obstacles.

Methods

A retrospective analysis was performed on patients admitted for resection of pituitary adenomas by a single surgeon at the University of Mississippi Medical Center. The control (non-ultrasound) group consisted of twelve (n=12) patients who received surgery without IOUS guidance, and the IOUS group was composed of fifteen (n=15) patients who underwent IOUS-guided surgery. Outcome measures used to assess the side-firing IOUS were the extent of tumor resection, postoperative complications, length of hospital stay (LOS) in days, operative time, and self-reported surgeon confidence in estimating the extent of resection intraoperatively.

Results

Preoperative data analysis showed no significant differences in patient demographics or presenting symptoms between the two groups. Postoperative data revealed no significant difference in the rate of gross total resection between the groups (p = 0.716). Compared to the non-US group, surgeon confidence was significantly higher (p < 0.001), and operative time was significantly lower for the US group in univariate analysis (p = 0.011). Multivariate analysis accounting for tumor size, surgeon confidence, and operative time confirmed these findings. Interestingly, we noted a trend for a lower incidence of postoperative diabetes insipidus in the US group, although this did not quite reach our threshold for statistical significance.

Conclusion

Incorporating IOUS as an aid for endonasal resection of pituitary adenomas provides real-time image guidance that increases surgeon confidence in intraoperative assessment of the extent of resection and decreases operative time without posing additional risk to the patient. Additionally, we identified a trend for reduced diabetes insipidus with IOUS.

Intraoperative Ultrasound for Bowel Deep Infiltrating Endometriosis: A Preliminary Report

The decision to perform either conservative surgery or segmental bowel resection for bowel deep infiltrating endometriosis (DIE) is made intraoperatively, after a preoperative assessment, based on the nodule's features. We introduce a technique to evaluate DIE bowel nodules using laparoscopic intraoperative ultrasound (US) during laparoscopic radical treatment of 9 cases of DIE invading the bowel. Once the bowel lesion was isolated, an intraoperative 12-4-MHz US transducer was placed on the surface of the nodules to study their US features and to gain measurements. Deep infiltrating endometriosis nodules appear at intraoperative US as hypoechoic elliptical lesions with a clear definition of margins and the depth of infiltration of the rectal wall.

Prognostic factors and therapeutic effects of different treatment modalities for colorectal cancer liver metastases

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignant tumors in China, and the liver is the most common metastatic site in patients with advanced CRC. Hepatectomy is the gold standard treatment for colorectal liver metastases. For patients who cannot undergo radical resection of liver metastases for various reasons, ablation therapy, interventional therapy, and systemic chemotherapy can be used to improve their quality of life and prolong their survival time.

AIM

To explore the prognostic factors and treatments of liver metastases of CRC.

METHODS

A retrospective analysis was conducted on 87 patients with liver metastases from CRC treated at the Liaoning Cancer Hospital and Institute between January 2005 and March 2011. According to different treatments, the patients were divided into the following four groups: Surgical resection group (36 patients); ablation group (23 patients); intervention group (15 patients); and drug group (13 patients). The clinicopathological data and postoperative survival of the four groups were analyzed. The Kaplan-Meier method was used for survival analysis, and the Cox proportional hazards regression model was used for multivariate analysis.

RESULTS

The median survival time of the 87 patients was 38.747 ± 3.062 mo, and the 1- and 3-year survival rates were 87.5% and 53.1%, respectively. The Cox proportional hazards model showed that the following factors were independent factors affecting prognosis: The degree of tumor differentiation, the number of metastases, the size of metastases, and whether the metastases are close to great vessels. The results of treatment factor analysis showed that the effect of surgical treatment was better than that of drugs, intervention, or ablation alone, and the median survival time was 48.83 ± 4.36 mo. The drug group had the worst prognosis, with a median survival time of only 13.5 ± 0.7 mo (P < 0.05). For patients with liver metastases of CRC near the great vessels, the median survival time (27.3 mo) of patients undergoing surgical resection was better than that of patients using other treatments (20.6 mo) (P < 0.05).

CONCLUSION

Patients with a low degree of primary tumor differentiation, multiple liver metastases (number of tumors > 4), and maximum diameter of liver metastases > 5 cm have a poor prognosis. Among drug therapy, intervention, ablation, and surgical treatment options, surgical treatment is the first choice for liver metastases. When liver metastases are close to great vessels, surgical treatment is significantly better than drug therapy, intervention, and ablation alone.