Lumbar Spine Screw Placement Training Tool #0

This repository contains the 3D printing files and documentation for creating a cost-effective, fluoroscopy-compatible L4-L5 spine model for pedicle screw placement training. The model features innovative use of barium-enhanced coating and PETG material, providing both structural integrity and radiographic visibility at a fraction of the cost of commercial alternatives. Citation If you use these files, please cite: Bölük, Mustafa Serdar MD; Akbulut, Bilal Bahadır MD; Yurtseven, Taşkın MD; Biçeroğlu, Hüseyin MD. Novel Barium-Enhanced 3-Dimensional-Printed Spine Model for Pedicle Screw Training: A Cost-Effective Solution and Educational Validation. Operative Neurosurgery ():10.1227/ons.0000000000001602, May 7, 2025. | DOI: 10.1227/ons.0000000000001602

ASSEMBLY AND USE VIDEO: 

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Material Requirements

PETG filament for vertebral models 

Barium sulfate (BaSO₄) Water-soluble white wall paint for the image intensifier

Room temperature vulcanizing silicone (Shore hardness 5 or 10) for soft tissue 

MDF board or a table. 

Wood screws to secure the system to the table/MDF board or long M3 nut and bolts to secure them after drilling a whole for the platform. Either option works.

4 M3 nuts and bolts to close the lid.

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Printing Specifications Primary Model (Ender-3 S1)

Walls: 3 Infill: 30% adaptive Layer height: 0.2mm Top layers: 4

Alternative Settings (Bambu Lab P1S)

Walls: 2 Infill: 30% adaptive Layer height: 0.2mm Top layers: 3 Top shell thickness 0.6

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Assembly Instructions

Print L4-5Spine model using provided PETG settings. 

Print the silicone mold file. Then prepare the mold silicone as specified on the silicone you have purchased. Remember to use vinyl gloves only, as latex inhibits the vulcanization process leaving you with a sticky mess…

How to handle silicone: https://formlabs.com/asia/blog/how-to-make-silicone-molds/ TL;DR: You need a well ventilated area, some vinyl gloves, silicone release spray. Spray the spray to the mold. After mixing the RTV Shore 5 silicone in quantities specified by the producer, you just pour into the mold.  Shake the mold a bit or tap it to the table to release the bubbles. Wait 24 hours.

Prepare barium coating (10% BaSO₄ in water-soluble white paint). This is a mostly safe material, but paint smells awful for days, so better to do this in a place you won't be using for some days, I've done it in the basement of our facility.

Apply three coats of barium solution one day apart, so it sticks better. Take care to not get too much paint on the bottom of the sliding mechanism of the model, but honestly, the paint drips on to it over time when curing, so after everything is done, you'll have to clean the base with some paint scrapers. I suggest some heavy duty gloves.

The ScrewBox and ScrewBoxLid. Print these out. It's more secure to drill holes on the bottom of a MDF board or a normal board. To do this, you'll have to mark where the holes will go using some pen. Then drill holes, place a bolt and attach a nut to the other side. But this might be a bit hard to align, so maybe just use some wood screws and drill it in. It'll be fine.

After sliding the model in, you put the lid on, secure with M3 nut and bolts. Place the Silicone cover on top of the model, covering where the pedicles are. 

I've not included the L4-5 cord mold in the files, the silicone tends to block some of the Xrays, so since it's not really necessary when training L4-5 screws, I omit this. For discectomies, I can provide it.

OPTIONAL IF YOU HAVE REGULAR SURGICAL SCREWS AVAILABLE:

Using a T25 torx head screwdriver, attach the custom screwdriver rod system to the screwdriver, then lock with the noslip piece, then glue that nonslip piece in place. The problem with this is that is you might not have the torx screwdriver with the correct size, so it might not fit, ensure both screws and screwdriver are size  T25.

For the screws, using torx head 5.5x50 diameter screws, thread them through the custom screwheads. And that's about it.