New Public Defence

Public Defence: Egidijus Pelanis

On February 14th 2023, Egidijus Pelanis MD has defended the thesis “Assessment of treatment and visualization methods for minimally invasive liver surgery” for the degree of PhD (Philosophiae Doctor).

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Summary
Liver metastases are common in patients with colorectal cancer, one of the most common types of cancer in the World. Surgical removal (resection) is the standard of care and can be performed as an open procedure or minimally invasively - laparoscopically.
The main objective of this doctoral thesis work was to advance further and evaluate methods, techniques, and technologies for minimally invasive liver surgery in current workflows and to explore potential future workflows with enhanced visualization methods outside and inside the operating room.
In the 1st study, perioperative data and long-term outcomes were studied in patients after laparoscopic parenchyma-sparing liver resections (LPSLR) for colorectal metastases. LPSLR is feasible and safe for colorectal liver metastases patients and is associated with satisfactory surgical and long-term oncological outcomes. LPSLR presents surgical outcomes comparable to open surgery alternatives.
In the 2nd and 3rd studies, a mixed reality application was developed to visualize 3D models by processing medical images. Clinical use cases, demonstrations, and questionnaires assessed the application. Mixed reality applications could be integrated into clinical routines with positive feedback and recommendations from clinicians. Viewing patient-specific 3D models in mixed reality has reduced the time needed for a task requiring spatial understanding.
The 4th and 5th studies were preclinical studies simulating laparoscopic liver resection with navigation. Intraoperative imaging significantly improves the accuracy of the laparoscopic navigation system for liver surgery compared to preoperative imaging. A user-induced error has a significant effect on point-to-point registration for laparoscopic navigation. A laparoscopic guidance system for liver resection can be achieved with clinically acceptable accuracy in a hybrid operating room by using fiducials inserted into the liver.