Intraoperative ultrasonography during planned liver resections: why are we still performing it?

Background: Intraoperative ultrasonography (US) is used in many centers before oncologic liver resections to detect additional tumors and to evaluate the relationship of tumors to major vascular structures. As preoperative imaging improves, it is expected that the diagnostic yield from intraoperative US will diminish. In this study we attempt to determine if fewer unrecognized tumors were being detected and whether intraoperative US is having less impact on surgical decision making. Methods: We compared 50 consecutive cases (mean age = 57.2 +/- 10 years; 27 men) who underwent laparotomy for a planned resection of primary liver malignancies or metastases between September 2003 and July 2005 with 50 consecutive cases (mean age = 56.9 +/- 14 years; 25 men) between January 1999 and September 2003. Dedicated intraoperative liver US was performed or supervised by a gastrointestinal radiologist using a 5.0-MHz linear- or curvilinear-array transducer during each procedure. Results: The rate of detecting unrecognized tumors has not changed significantly (14% vs. 20%, p = 0.70). The use of US to establish the relationship between tumor and the vasculature has not changed (48% vs. 60%, p = 0.23). The percentage of cases where the Us findings were responsible for altering surgical management was 20% for both groups. The resection rate was 72% for both groups. The negative resection margin rate has also not changed significantly (86% vs. 69%, p = 0.09). Conclusions: Despite the advances in cross-sectional imaging, the frequency of unrecognized tumors found during intraoperative liver US and its use for surgical guidance has not changed significantly. Currently routine intraoperative US alters the management of approximately one fifth of our patients undergoing attempted liver resection for primary malignancies or metastases.