TissueDB/Simulators/Patent Ductus Arteriosus Ligation Simulator

This simulator trains the dissection and double-ligation technique for patent ductus arteriosus (PDA) closure via left thoracotomy. A gelatin-glycerol vascular model is cast in a custom mold to replicate the PDA, aorta, and parietal pleura, then mounted in a wooden training box equipped with electronic proximity sensors. The sensor feedback system provides three levels of real-time psychomotor feedback: LED colour-coded force warnings, continuous digital score display (0–9), and a final calculated performance score. An augmented reality mobile app records training sessions and can detect potential emergency situations such as PDA rupture. Designed for surgical trainees in low- and middle-income countries who may lack access to instructor-supervised simulation facilities. Developed by the SELF-Training team as part of the Global Surgical Training Challenge (2021).

Step 1. Connect the three green plastic components to one another as shown on video, and place them in the fitted space in the bottom half of the mold.

Step 2. Push the four nozzles into the top half of the mold, ensuring that the tips of the nozzles pass all the way through.

Step 3. Place the top half of the mold in position and use rubber bands to seal the halves firmly together. Set aside on paper or cloth towels while making the molding material.

Step 1. Place measuring jug on scale, zero the scale, and add 40 g of glycerol.

Step 2. Zero the scale and add 15 g of gelatin.

Step 3. Zero the scale, add 0.5 g of powdered pigment, and spread powdered materials across the surface of the glycerol.

Step 4. Add cold tap water to the 100 ml fill line of the measuring jug. Stir until fully dissolved and let sit for 20 minutes to congeal.

Step 5. Transfer mixture into cooking pot. Spread over surface and mix over low heat (do not boil) for approximately 10 minutes until fully liquefied.

Step 6. Remove plunger from syringe and ensure syringe cap is secure. Fill syringe carefully with hot mixture, replace plunger, turn upside down and remove cap, and slowly push plunger until no air remains.

Step 7. Screw the syringe end into each of the four filling nozzles on the model and firmly push hot material through the nozzle until the mold is completely filled. Leakage through the seam between the two sides of the mold is normal.

Step 8. Refrigerate the mold overnight. Excess mixture remaining in the syringe can be ejected into a container and refrigerated for future use.

Step 1. Remove rubber bands and nozzles, peel away excess gel from outside of mold (the excess material can be saved and reused), and carefully separate the two sides of the mold.

Step 2. Use a scalpel or craft knife to remove the gel from the V-shaped ends of the plastic inserts.

Step 3. Gently twist and pull to remove the smaller of the two long inserts, using knife to loosen from ends as necessary.

Step 4. Use tweezers to loosen central connecting pin from larger long insert, then gently twist and pull to remove the long insert.

Step 5. Push connecting rod into larger vessel and use tweezers to remove.

Step 1. Slot the base of the box into the two side panels with the four holes.

Step 2. Slot the side panel with three holes onto the assembly.

Step 3. Slot the side panel with many holes onto the assembly. This panel is used for mounting the electronics.

Step 4. Assemble the internal frame as shown in the assembly diagrams.

Step 5. Insert the internal frame into the main box assembly.

Step 6. Insert the lid into the two slots at the top of the box assembly.

Step 7. Assemble the phone holder by slotting the two combs into the two arms. Adjust the width by slotting the arms into the different slots on the combs to accommodate different phone sizes.

Step 8. Slot the phone holder onto the lid of the box in a central position. This provides a phone camera with a tall and centralized field of view for recording surgical training exercises.

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Step 1. Install the augmented reality app on a smart phone or tablet using one of the following links:

• Android: https://play.google.com/store/apps/details?id=com.NMIS.OrganlikeARDR
• Apple iOS: https://testflight.apple.com/join/7CdIIjM4

Note: The simulator box arrives with all electrical sensor equipment pre-configured and ready to use. Users may also build additional simulator boxes from scratch by purchasing the electrical components for less than US$25 total. See the electrical sensor configuration instructions for DIY assembly details.

The simulator box is shipped with electronic sensors pre-configured. For users building additional boxes from scratch, full electrical sensor configuration instructions (including schematic diagrams and video walkthrough) are available at:

• Electrical Sensor Configuration Instructions

Total cost for all electronic components: less than US$25.

The augmented reality app provides visual overlay and sensor data monitoring:

• Android: https://play.google.com/store/apps/details?id=com.NMIS.OrganlikeARDR
• Apple iOS: https://testflight.apple.com/join/7CdIIjM4

The app monitors distance sensor signals in real time and can detect potential emergency situations (e.g., excessive tissue displacement indicating PDA rupture risk), triggering a warning message with action options for the trainee.