Saturday 23 September 2017

Rhinoplasty planning with RhinOnBlender addon

Rhinoplasty planning steps: Measurements, sculpture, post guide, pre-post guide.
I always thought that plastic surgeons were professionals that only served the moneyed elite and who passed away from the treatments that benefit the users of the Brazilian public health system. When I was asked to teach computer graphics courses to these specialists, I had the opportunity to follow their work more closely, which, unlike what I assumed, involves a routine of scientific production, clinical care and a tremendous effort to offer the general population the possibility of solving a series of problems, ranging from a structure that leverages the self-esteem of this individual, to a procedure that returns a motor skill that was limited, either by accident or pathology.

By teaching classes and adjusting Blender parameters to the needs of plastic surgeons, I realized that activities could be performed much more effectively if the commands were grouped into scripts, and these, in turn, were attached to buttons and pre-structures defined, provided by the graphical interface itself.

The idea of creating RhinOnBlender came out after we made Cork on Blender (boolean addon) available and started working on OrtogOnBlender (orthognathic surgery planning). Although the latter is not available, for the moment to the general public, we are already using it for the planning of orthognathic surgeries, which deal with facial deformations. Similar situation has happened with the rhinoplasty addon. It was born from a process of simplifying commands to beginners and we are already using it for planning, yesterday we did one!

Automatic attenuation of the 3D mesh by photogrammetry - option implemented just now
The development of the tool is the result of a partnership with three specialists: Dr. Pablo Maricevich (Cir. Plastic), Dr. Rodrigo Dornelles (Cir. Plastic) and Dr. Everton da Rosa (Cir. Dentist). Two plastic surgeons and a dentist? That's right, although they look like different areas, the planning tools of one field and another are quite compatible, what we did was the joint development over the cases that we have worked on since the year 2014.

Experimental guide made from pre and post surgical mesh
The goal of this project is to offer an alternative based on freeware and free software. The video featured in this post uses a face scanned in 3D by photos (photogrammetry), there are  licenced, freeware, free software, offline and online options of this tool, such as the popular Photoscan, Recap 360, MVE and OpenMVG. But nothing prevents the specialist from importing a face scanned by laser scanner or structured light or even reconstructed from a CT scan. The point here is that there is a possibility to do a good job without having to pay for the tools, since we have free photogrammetry and Blender and its addons are also free!

Experimental guide from different viewpoints
Speaking of addons, I can not fail to mention the enormous help of two developers: Dalai Felinto who wrote Cork on Blender, a tool that boosts the work with boolean, essential when it comes to modeling for healthcare. Also the specialist in dental tools, Patrick Moore, better known in the cybernetic environment as Patmo141. The addons developed by him are geniuses and two of them are used in ours, Cut-Mesh, which lets you draw on a mesh and isolate the desired part and Object-Align, which as its name says, aligns objects, something that we don't have available in the standard Blender installation.

We are working hard. At each surgical analysis and surgical planning we see the need for repairs and increases in the code. Once the tool is more mature and fluid, we will make it available to anyone who has an interest. We hope this happens as soon as possible.

Until then!

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