Perceptions of Porta Celiac Vascular Model
Condition: Educational Problems
Study type: Interventional

Summary: 
      Background: Primary aspect of hepatic navigation surgery is the identification of source
      vascular details to preserve healthy liver which has a vascularity anatomy quite challenging
      for the young surgeons. The purpose was to determine whether three-dimensional (3D) vascular
      pattern models of preoperative computed tomography images will assist resident-level trainees
      for hepatic surgery.

      Methods: This study was based on the perception of residents who were presented with 5
      different hepatic source vascular pattern and required to compare their perception level of
      CT, and 1:1 models in terms of importance of variability, differential of patterns and
      preoperative planning.

      Results: All subspecialties agree that models provided better understanding of vascular
      source and improved preplanning. Five stations provided qualitative assessment with results
      showing the usefulness of porta-celiac models when used as anatomical tools in preplanning
      (p=0.04), simulation of interventional procedures (p=0.02), surgical education (p=0.01). None
      of the cases a scored less than 8.5. Responses related to understanding variations were
      significantly higher in the perception of the 3D model in all cases, furthermore 3D models
      were more useful for seniors in more complex cases 3 & 5. Some open-ended answers: "The 3D
      model can completely change the operation plan" One the major factors for anatomical
      resection of liver transplantation is the positional relationship between the hepatic
      arteries and the portal veins. Conclusions: The plastic-like material presenting the hepatic
      vascularity enables the visualization of the origin, pattern, shape, and angle of the
      branches with appropriate spatial perception thus making the well-structured.
    

Detailed description: 
      2.1. Research Design The study group consisted of Ege University, Faculty of Medicine general
      surgery residents (n:22). A five-station carousel composed of vascular patterns such as
      classical porta-celiac, portal vein type 2, portal vein type 3, separate branches origin of
      celiac trunk and portal vein pattern located between the right and the left hepatic artery.
      Each station contained the CT, and life size models of the cases. As data collection tool, a
      descriptive rating scale was used to evaluate the perceptions of each of the methods (CT and
      3D solid model) in terms of their usefulness in knowing the variations, perceiving the
      problem, their effectiveness in differential diagnosis and preoperative planning.

      Arterial variations were classified according to previous authors. In the classical anatomy,
      the common hepatic artery arises from the celiac trunk to form the gastroduodenal and proper
      hepatic arteries, and the latter dividing distally into right and left branches. Separate
      branches origin of the celiac trunk such as the artery from the abdominal aorta were modeled
      individually in cases of variant neighborhood. Portal variations were classified as the
      portal vein types. Type 1 is the classical appearance, in which the right portal vein and
      left portal are present as independent trunks. In type 2, the right anterior portal vein,
      right posterior portal vein, and left portal vein trifurcate from the main portal vein. In
      type 3, the right posterior portal vein comes directly from the middle portal vein, and the
      left portal vein and right anterior portal vein emerge from a common trunk.

      The study was approved by the suitably constituted Ethical Committee at Researches Department
      of Ege University (18-5/45), within which the work was undertaken, and the study conforms to
      the Declaration of Helsinki. Clinicaltrails number is EGE18-6.134.

      2.2. Selection of the samples The patients in this study were chosen among the ones who
      consulted to Ege University Faculty of Medicine, Department of General Surgery, Hepatobiliary
      Surgery and Transplantation Division for diagnose between September 2016 and January 2018. CT
      archives were screened and 100 eligible people (age: 18-62) with porta-celiac vascular
      patterns were selected. Patients whose radiological imaging results were suitable for
      modeling and the ones with no previous operation or pathology that may cause anatomical
      differences were included in the study.

      2.3. Stations Five case carousel that could serve as an example for variational hepatic
      vascularity was defined with the consensus of experts in medical education, anatomy,
      radiology and liver transplantation team. The carousel included the following 5 cases.

      Case 1. Portal vein with Type 3 classification pattern. Case 2. Normal classification
      porta-celiac vascular pattern. Case 3. Vascular pattern with the separate branch origin of
      celiac trunk. Case 4. Portal vein between the right and the left hepatic artery. Case 5.
      Portal vein with Type 2 classification pattern. 2.4. Image post-processing and segmentation
      DICOM data from CT and MRI sections of the patients were obtained using free 3D Slicer
      (version 4.10.1) software. Segmentations of the portal vein, hepatic vein, splenic vein were
      automatically generated from the venous phase, while the celiac trunk and hepatic artery were
      manually traced from the arterial phase.

      2.5. Creating life-size patient-specific porta-celiac vascular model Model CT's were measured
      in order to verify 1:1 modelling and the printing the process was carried out with 3D
      printers of Mass Portal Pharaoh xd 20. Model production took a total of 24 hours; 4 for
      segmentation, 3 for editing, 15 for printing, and 1 hour for post-print processing. Arterial
      vessels were color-coded red, and the portal vein blue by the visualization team.

      2.6. Quantitative assessment of model accuracy Measurements of the anatomical structures were
      performed and compared between the original CT images, and the CT images of the 3D model. The
      morphometric values such as inter-arterial distances (distances between arterial origins),
      inter-venous distances and the distance between the artery and the vein were noted.
      Measurements were compared for original CT images, the 3D rendered files, and the 3D vascular
      models. The repetition rate of the measurements which were done by two autonomous spectators,
      was 3 times at every scene and the mean values were taken as ultimate output and also
      calculated for further statistical analysis. The spectators performed with exceptional
      correlation (r=0.99, P<0.001).

      2.7. Workshop During the workshop, 30-minute lectures were given by the expert team on
      variable vascular pattern, arterial structures relationship with venous structures and models
      in diagnosis. For each station, a period of 5-10 minutes was given.

      2.8. Survey A multi-item survey was prepared to assess fellow's perception of residency
      training. The survey was utilized by our group, understanding of patient vascular anatomy,
      awareness of the changes based on variations, independent decision-making, differential
      diagnosis, plan on key surgical steps, and preparation for unexpected bleeding. The answers
      to the questions asked for each case were analyzed to include senior (3 years and over) -
      junior (1-2 years) residents.

      2.9. Statistical analysis Data are entered into SPSS 24.0 for statistical analysis.
      Continuous variables were presented as mean ± standard deviation. Wilcoxon Signed Ranks Test
      was used to determine any significant differences in the measurements between the original CT
      images, 3D rendered images, the 3D model and CT images of the 3D model. Statistical
      significance was defined as a p value of less than 0.05.
    

Intervention name(s): Survey
Intervention type(s): Other
Intervention description(s): A multi-item survey was prepared to assess fellow's perception of residency training. The survey was utilized by our group, understanding of patient vascular anatomy, awareness of the changes based on variations, independent decision-making, differential diagnosis, plan on key surgical steps, and preparation for unexpected bleeding. The answers to the questions asked for each case were analyzed to include senior (3 years and over) - junior (1-2 years) residents.Assistants spend 45 minutes in the survey. Data are entered into SPSS 24.0 for statistical analysis. Wilcoxon Signed Ranks Test was used to determine any significant differences in the measurements between the original CT images, 3D rendered images, the 3D model and CT images of the 3D model. Statistical significance was defined as a p value of less than 0.05. Junior assistants stated that they perceived 2D image statistically better than 3D models compared to the senior assistants (Kruskal-Wallis Test).
Intervention model: Sequential Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Patient-specific modelling; Graduate surgical education