Morphological changes on the human liver during minimally invasive surgery: Implications for image-guided...

Minimally invasive liver resection and ablation depend on surgical planning and image guidance. Surgical planning is normally based on preoperative imaging. The position, shape, and volume of the abdominal organs change during laparoscopy, which challenges image registration and reduces surgical precision. This study aims to analyze the morphological changes of the liver and spleen from pre- to intraoperative (with pneumoperitoneum) computed tomography (CT) images.

We used portal venous phase pre- and intraoperative CT images from 15 patients who underwent laparoscopic liver ablation in general anesthesia under 12 mmHg pneumoperitoneum at Rikshospitalet, Oslo University Hospital, Oslo, Norway. A rigid registration, based on spinal landmarks, was used to register intraoperative to preoperative CT images. Morphological features were extracted and statistically analyzed for the liver and spleen.

The liver volume decreased by 12% from the preoperative to the intraoperative CT scan. The mean cranial movement of the liver was 45 mm between pre- and intraoperative CT images. A few morphological radiomic features changed significantly for both liver and spleen.

To the best of our knowledge, this is the first published study in humans to analyze the morphological changes of the liver and spleen during pneumoperitoneum. The results show a significant reduction in liver volume and change in shape and position of the liver during such laparoscopy. This deformation from preoperative to intraoperative imaging poses significant challenges for image registration, which is crucial for surgical navigation. These findings highlight the need for updated intraoperative navigation using imaging and registration to ensure accurate surgical planning.