Clinical Scorecard: Ultrasound-Guided Resection of Hepatic Tumors: A Navigational Approach
At a Glance
Category
Detail
Condition
Hepatic tumors requiring surgical resection
Key Mechanisms
Intraoperative ultrasound imaging combined with electromagnetic (EM) tracked surgical instruments to generate 3D liver models for navigation
Target Population
Patients aged 18 years and older with hepatic tumors > 2 cm visible on intraoperative ultrasound
Care Setting
Intraoperative setting during liver tumor resection surgery
Key Highlights
Conventional 2D ultrasound is operator-dependent and disrupted by electrocautery gas bubbles, leading to a 14–22% incidence of incomplete (R1) resections.
EM image guidance system generates 3D liver models directly from intraoperative ultrasound, eliminating reliance on preoperative imaging registration and improving navigation accuracy for visible tumors.
A prospective feasibility study with 25 patients demonstrated clinical feasibility and accuracy of ultrasound-based navigation using tracked instruments and real-time 3D visualization.
Guideline-Based Recommendations
Diagnosis
Use intraoperative ultrasound to localize tumor borders and assess spatial relationships to intrahepatic vasculature.
Preoperatively delineate liver parenchyma and target lesions from recent contrast-enhanced CT or MRI for spatial context.
Management
Employ electromagnetic tracking of ultrasound transducer, vessel sealer, and surgical pointer to enable real-time 3D navigation during resection.
Mobilize liver intraoperatively to expose tumor and attach EM sensor near tumor to compensate for respiratory and surgical manipulation movement.
Use rigid single landmark registration aligning tracked tool orientation with anatomical reference points to integrate preoperative imaging with intraoperative navigation.
Monitoring & Follow-up
Continuously track surgical instruments and update 3D models intraoperatively to maintain accurate navigation.
Monitor ultrasound image quality and navigation system feedback to guide precise tumor resection.
Risks
Potential interference of electromagnetic field generator with pacemakers—exclude patients with pacemakers from EM navigation.
Limitations in navigation accuracy due to liver deformation and tumor progression between preoperative imaging and surgery.
Patient & Prescribing Data
Adults with hepatic tumors > 2 cm visible on intraoperative ultrasound, excluding those with pacemakers or scheduled for anatomical hemi-hepatectomy
Ultrasound-based EM navigation may improve intraoperative tumor localization and resection accuracy, potentially reducing incomplete resections compared to conventional methods.
Clinical Best Practices
Optimize surgical workflow by initial navigation cases before accuracy analysis.
Calibrate EM sensor adapters for ultrasound transducer and vessel sealer prior to surgery.
Use sterile covers for ultrasound transducer to maintain sterility while allowing external sensor attachment.
Place EM field generator near surgical field for optimal instrument tracking.
Apply Dermabond adhesive to affix EM sensor to liver parenchyma near tumor for motion compensation.
by Karin A. Olthof, Theo J. M. Ruers, Tiziano Natali, Lisanne P. J. Venix, Jasper N. Smit, Anne G. den Hartog, Niels F. M. Kok, Matteo Fusaglia, Koert F. D. Kuhlmann
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