Table 1.

Summary of main problems and corresponding solutions for the digital endoscopic endonasal transsphenoidal pituitary surgery model

Problem	Cause	Solution	3D manipulation tools	Tools
File format transformation	DICOM file cannot be edited directly	Upload the DICOM file and save it as STL file	Mimics (17.0)	File $>$ New Project Wizard File $>$ Export $>$ ASCII STL Files
Non-skull parts	The result of CT scanning includes all compositions of the head	Set the thresholding value Select the parts in 3D and delete them		Menu bar $>$ Segmentation $>$ Thresholding Menu bar $>$ Segmentation $>$ Edit Mask in 3D $>$ Lasso $>$ Remove
Missing structure	The limited accuracy of CT scanning and automatic threshold segmentation	Paint the parts slice by slice		Menu bar $>$ Segmentation $>$ Edit Masks $>$ Circle $>$ Draw
The surgical area should be printed by the breakable and low-cost material (plaster)	The sellar region will be broken during the surgery	Segment the skull	3ds Max (2014)	Slice $>$ Remove the top/Remove the bottom
Make internal carotid arteries, optic nerves and corresponding molds	The soft tissues should be protected carefully during the real surgery	Draw the objects and use Boolean operation		Compound Objects $>$ Boolean
Wrong positions of holes	The limitation of CT scanning and automatic threshold segmentation	Fill the holes	Geomagic Studio (13.0)	Fill Holes $>$ Fill All
Inappropriate distribution of grids	The limitation of CT scanning	Analyze and optimize		Polygons $>$ Repair $>$ Remesh Polygons $>$ Smooth $>$ Relax Polygons $>$ Repair $>$ Decimate