Intraoperative ultrasound for the colorectal surgeon: current trends and barriers

Abstract

Up to two thirds of patients diagnosed with colorectal cancer (CRC) develop colorectal liver metastases (CRLMs) and one quarter of patients present with synchronous metastases. Early detection of CRLM widens the scope of potential treatment. Surgery for CRLM offers the best chance of a cure. Current preoperative staging of CRC relies on computerized tomography and magnetic resonance imaging. Intraoperative ultrasound (IOUS) scans and contrast-enhanced IOUS (CE-IOUS) have been demonstrated to detect additional metastases not seen on routine preoperative imaging. IOUS is not widely used by colorectal surgeons during primary resection for CRC. Confident use of IOUS/CE-IOUS during primary resection of CRC may improve decision-making by providing the most sensitive form of liver staging even when compared with magnetic resonance imaging. This may be particularly important in the era of laparoscopic resections, where the colorectal surgeon loses the opportunity to palpate the liver. There are several implied barriers to the routine use of IOUS/CE-IOUS by colorectal surgeons. These include time pressure, familiarity with techniques, a perceived learning curve, cost implications and limitation of the modality due to operator variations. Inclusion of IOUS in the training of colorectal surgeons and further investigation of potential benefits of IOUS/CE-IOUS could potentially reduce these barriers, enabling usage during primary resection for CRC to become more widespread.

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

“…In addition, the widespread use of ultrasound in surgery can improve the rate of intraoperative exploration. For metastatic lesions not found before surgery, ultrasound can help to locate the lesion and provide a more reasonable surgical treatment in a timely manner to avoid residual tumors and improve the rate of R0 resection[ 29 , 30 ]. For all selected patients in this study, intraoperative ultrasound localization was used (Figures 5 and 6 ) to ensure R0 resection.…”

Liver ultrasound: A key procedure in the surgeon's toolbox

“…US in the operating room can also be performed as a screening procedure during cancer operations where there is a risk of liver metastases. When used as a screening procedure, intraoperative US detects occult liver metastases during primary colorectal cancer resections not seen by preoperative imaging 1,2 . Important liver anatomic information can also be assessed by the US procedure, such as the location of the hepatic and portal veins to mark the limits of segmental liver resection.…”

Use of Intraoperative Ultrasound (IOUS) in Liver Surgery

“…IOUS is more superior in detecting liver lesion than preoperative MRI and CT scan with sensitivity of 95-100% in comparison to others, 80% for CT, and 70% for percutaneous ultrasound. It is very helpful in liver resection for liver malignant tumors and will improve patient survival by taking safety liver resection; with the use of IOUS, limited liver tumor resection can be done in a non-segmental way and will improve patient survival especially in a patient with hepatocellular carcinoma with a background of cirrhosis [25][26][27][29][30][31][32][33]. IOUS may have difficulty in detecting small liver lesion in a fatty liver; however, the use of contrast-enhanced ultrasound will be more beneficial [22][23][24]28].…”