A training phantom for a vesicovaginal fistula repair with the transvaginal approach

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Abstract

Background: In Africa, many women suffer from vesicovaginal fistulas. In this study, a phantom model for a vesicovaginal fistula repair was developed that can be produced and used in Africa, to train medical doctors in the treatment of simple fistulas by the transvaginal approach.
Method of production: The phantom consists out of 3D printed PLA parts and silicone parts. The framework and the moulds for the required organs were 3D printed with PLA, and silicone was then poured into the moulds. To determine which tissue-mimicking silicone material to use, a test focused on the tendency to rupture, and a tensile test were performed. It followed that to mimic the vaginal tissue, Dragon Skin 10 with 11% silicone oil was most suitable. To mimic the bladder tissue both Dragon Skin 10 with 11% silicone oil and Dragon Skin 10 with Slacker could be suitable. Therefore, two bladders with both materials were made. The cervix, the vulva, and a plate that closes off the bladder were all made with Dragon Skin 10 without an additive. To mimic the urethra a tube of natural rubber was used, and to mimic the connecting fascia between the bladder and vagina and to connect the organs silicone glue was used.
Testing results: A clinical validation test was performed by two dutch gynaecologists to validate the overall initial model, the representation of the materials, and whether the procedural steps of excising, dissecting, and suturing of the tissue could be performed. The water-tightness was not tested in this stage yet. It mainly followed that the angle of the model should be adjusted to the Trendelenburg position and that the working space should be broadened. Both improvements were processed in an updated final model, on which a secondary test was performed by a pelvic surgeon. In this stage also a water-tightness test was performed, from which it followed that the bladder with Slacker became watertight after suturing, the bladder with silicone oil, however, did not. Therefore, Dragon Skin 10 with Slacker is most suitable for mimicking the bladder tissue. The material costs for the permanent parts of the final phantom model are €14,23 and for the replaceable parts, the material costs are €5,38.
Conclusion: All procedural steps could be performed on the final phantom model without any problems. And, the model can be produced locally, while keeping the costs low. Overall, the model is suitable to be used as a phantom to train medical doctors in the treatment of a simple vesicovaginal fistula repair with the transvaginal approach.