"Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has."

Original article
peer-reviewed

# Three-Dimensional Printing of a Hemorrhagic Cervical Cancer Model for Postgraduate Gynecological Training

### Abstract

#### Introduction

A realistic hemorrhagic cervical cancer model was three-dimensionally (3D) printed and used in a postgraduate medical simulation training session.

#### Materials and methods

Computer-assisted design (CAD) software was the platform of choice to create and refine the cervical model. Once the prototype was finalized, another software allowed for the addition of a neoplastic mass, which included openings for bleeding from the neoplasm and cervical os. 3D printing was done using two desktop printers and three different materials. An emergency medicine simulation case was presented to obstetrics and gynecology residents who were at varying stages of their training. The scenario included history taking and physical examination of a standardized patient. This was a hybrid simulation; a synthetic pelvic task trainer that allowed the placement of the cervical model was connected to the standardized patient. The task trainer was placed under a drape and appeared to extend from the standardized patient’s body. At various points in the simulation, the standardized patient controlled the cervical bleeding through a peripheral venous line. Feedback forms were completed, and the models were discussed and evaluated with staff.

#### Results

A final cervical model was created and successfully printed. Overall, the models were reported to be similar to a real cervix. The models bled well. Most models were not sutured during the scenarios, but overall, the value of the printed cervical models was reported to be high.

#### Discussion

The models were well received, but it was suggested that more colors be integrated into the cervix in order to better emphasize the intended pathology. The model design requires further improvement, such as the addition of a locking mechanism, in order to ensure that the cervix stays inside the task trainer throughout the simulation. Adjustments to the simulated blood product would allow the bleeding to flow more vigorously. Additionally, a different simulation scenario might be more suitable to explore the residents’ ability to suture the cervical models, as cervical suturing of a neoplasm is not a common emergency department procedure.

#### Conclusion

3D-printed cervical models are an economical and anatomically accurate option for simulation training and other educational purposes.

### Introduction

The use of three-dimensional (3D) printing or rapid prototyping in medical simulation training is rapidly evolving [1]. 3D printed simulation has been studied in neurosurgery [2-11], plastic and reconstructive surgery [12-14], and cardiovascular surgery [15-16]. However, little research supports the use of this technology in gynecological simulation. We created a 3D-printed cervix and cervical neoplasm for use in resident-level gynecological simulation training. The style of 3D printing used in this study was fused deposition modeling (FDM), which involves laying down material along the X and Y axis, and then the Z axis, until object completion [17].

The department of obstetrics and gynecology has used a hybrid simulation to evaluate residents’ abilities to recognize and manage various gynecological emergencies. For the purpose of the current simulation, a cervical model simulates a bleeding cervical cancer. The primary limitations of current cervical models (Figure 1) in the simulation setting is that unlike a real cervix, they are extremely hard and do not have the capacity to bleed or be sutured. To address these limitations, the department collaborated with the Memorial University of Newfoundland (MUN MED) 3D team to develop a 3D-printed design and model that would address these limitations. Our study aim was to create a low-cost model that looked and felt realistic.

### Materials & Methods

The first iteration of the design for the 3D cervix model used historical cervical models as a starting point for overall design dimensions. From here, the design process was guided by physicians practicing in the department of obstetrics and gynecology. The design work was completed using 3D computer-aided design (CAD) software called SolidWorks (SolidWorks, Waltham, MA, USA). These designs were exported as STereoLithography files (STL), which is a compatible format for most 3D printers. All STL files can be made available for those interested through communication with the corresponding study author.

Each iteration of the cervix model was designed using very simple methods and basic SolidWorks features. The generic shape of the model determined the geometry of the initial sketch in SolidWorks (2015–2016). Some of the model designs used sketch features such as revolve and extruded cut, which helped to ensure uniformity and symmetry in the model.

After the cervix design was felt to be satisfactory, the tumor was added to the base model. The design file was loaded into a free software, MeshMixer (Autodesk, San Rafael, CA, USA), which allowed for the manipulation of triangle meshes constituting the 3D design work. In MeshMixer, the sculpt feature allowed for the creation and customization of a tumor-like mass on the cervix base model. This file was then exported as an STL file for printing. Numerous design alterations were made after prototyping several cervical iterations, which all followed the previously-described process. Additionally, multiple prints were necessary to determine the optimal print material, orientation, and use of support structures. The final 3D design of the cervical model in SolidWorks and the tumor addition in MeshMixer can be viewed in Figure 2.

The FDM 3D printers used for this study were the M3D Micro (M3D, Fulton, MD, USA) and LulzBot TAZ 6 (Aleph Objects, Loveland, CO, USA) (see Figure 3). The Micro has a 50–350 micron layer resolution, a 15 micron X and Y positioning accuracy, and requires a USB connection. The TAZ 6 uses automatic bed leveling, a heated polyetherimide print bed, an all metal extruder (LulzBot v2 Hot End) (Aleph Objects, Loveland, CO, USA), and a secure digital (SD) card for storing and printing files. The Micro was used to print the early prototypes of the cervix model; however, the TAZ 6 was used to create several functional prototypes, as well as the final version used in the simulation. The range of settings included fill densities, structural supports, bed adhesion tools, and print qualities.

Additionally, a variety of different filaments were used to create the cervix models. Polylactic acid (PLA) was used to create two of the models at the start of the process. This material is rigid and hard and was simply used to appreciate the overall dimensions of the design. The next material utilized was called Tough 3D Ink (FLX) and is produced by M3D. This material was much more flexible than the PLA, which allowed for the creation of a more realistic model. The final material utilized was called SemiFlex (NinjaTek, Manheim, PA, USA), which was the most suitable material for our study in terms of anatomical material realism. The diameter of the PLA and SemiFlex was 2.85 mm and that of the FLX was 1.75 mm. The PLA and SemiFlex models were printed using the TAZ 6, and the FLX models were only printed using the Micro. The SemiFlex material was the most similar to a human cervix as it was appropriately colored, more flexible, and could tear and be sutured. The final cervix model (Figure 4) was made of this material and featured a hardened neoplasmic mass with a softer cervix surface. A small opening was placed in the middle of the neoplasm as well as a larger hole in the external cervical os. During the simulation, intravenous tubing was connected to the base of the model, which allowed the standardized patient to "control the flow" of the simulated blood, thus creating the appearance of hemorrhaging through the cervical os and neoplasm. The evolution of the various 3D printed models can also be viewed in Figure 4.

The average time taken for printing the cervical model on the Micro was three hours 27 minutes, and the material used was 16.25 g. The average print time for the TAZ 6 was two hours 20 minutes, and the average material used was 23.1 g. After model design modifications were made following discussions amongst the research team, the final model was selected for use in simulation. There were four separate groups of residents; therefore, five cervical models were needed (one for a backup). All five of these models were printed successfully at the same time on the TAZ 6 with a total print time of six hours and 38 minutes and with 55 g of material used, at a total material cost of $8.80 CAN. The amount of material used varied greatly depending on the type of material and printer utilized. Overall, the average cost of each print was$1.26, whereas the average print cost for each material (FLX, PLA-I, SemiFlex) was $1.01,$0.53, and $1.76, respectively. The final model that was used in the simulation cost$1.76 to produce. Information regarding the time, cost, and materials used for each iteration of the design can be observed in Table 1.

### References

1. Bartellas MP: Three-dimensional printing and medical education: a narrative review of the literature. University of Ottawa Journal of Medicine. 2016, 6:38–43. 10.18192/uojm.v6i1.1515
2. Abla AA, Lawton MT: Three-dimensional hollow intracranial aneurysm models and their potential role for teaching, simulation, and training. World Neurosurg. 2015, 83:35–36. 10.1016/j.wneu.2014.01.015
3. Liew Y, Beveridge E, Demetriades AK, Hughes MA: 3D printing of patient-specific anatomy: a tool to improve patient consent and enhance imaging interpretation by trainees. Br J Neurosurg. 2015, 29:712–714. 10.3109/02688697.2015.1026799
4. Ryan JR, Chen T, Nakaji P, Frakes DH, Gonzelaz LF: Ventriculostomy simulation using patient-specific ventricular anatomy, 3D printing, and hydrogel Ccsting . World Neurosurg. 2015, 84:1333–1339. 10.1016/j.wneu.2015.06.016
5. Fasel JH, Uldin T, Vaucher P, Beinemann J, Stimec B, Schaller K: Evaluating preoperative models: a methodologic contribution. World Neurosurg. 2016, 89:681–685. 10.1016/j.wneu.2015.12.006
6. Khan IS, Kelly PD, Singer RJ: Prototyping of cerebral vasculature physical models. Surg Neurol Int. 2014, 5:11.
7. Klein GT, Lu Y, Wang MY: 3D printing and neurosurgery—ready for prime time?. World Neurosurg. 2013, 80:233–235. 10.1016/j.wneu.2013.07.009
8. Mashiko T, Otani K, Kawano R, et al.: Development of three-dimensional hollow elastic model for cerebral aneurysm clipping simulation enabling rapid and low cost prototyping. World Neurosurg. 2015, 83:351–361. 10.1016/j.wneu.2013.10.032
9. Tai BL, Rooney D, Stephenson F, et al.: Development of a 3D-printed external ventricular drain placement simulator: technical note. J Neurosurg. 2015, 123:1070–1076. 10.3171/2014.12.JNS141867
10. Waran V, Narayanan V, Karuppiah R, Owen SL, Aziz T: Utility of multimaterial 3D printers in creating models with pathological entities to enhance the training experience of neurosurgeons: Technical note. J Neurosurg. 2012, 120:489–492. 10.3171/2013.11.JNS131066
11. Wurm G, Lehner M, Tomancok B, Kleiser R, Nussbaumer K: Cerebrovascular biomodeling for aneurysm surgery. Surg Innov. 2004, 18:294-306. 10.1177/1553350610395031
12. Gerstle TL, Ibrahim AM, Kim PS, Lee BT, Lin SJ: A plastic surgery application in evolution: three-dimensional printing. Plast Reconstr Surg. 2014, 133:446–451. 10.1097/01.prs.0000436844.92623.d3
13. Chae MP, Rozen WM, McMenamin PG, Findlay MW, Spychal RT, Hunter-Smith DJ: Emerging applications of bedside 3D printing in plastic surgery. Front Surg. 2014, 2:1–14. 10.3389/fsurg.2015.00025
14. Bauermeister AJ, Zuriarrain A, Newman MI: Three-dimensional printing in plastic and reconstructive surgery: a systematic review. Ann Plast Surg. 2016, 77:569–576. 10.1097/SAP.0000000000000671
15. Kiraly L, Tofeig M, Jha NK, Talo H: Three-dimensional printed prototypes refine the anatomy of post-modified Norwood-1 complex aortic arch obstruction and allow presurgical simulation of the repair. Interact Cardiovasc Thorac Surg. 2015, 22:238–240. 10.1093/icvts/ivv320
16. Mahmood F, Owais K, Montealegre-Gallegos M, et al.: Echocardiography derived three-dimensional printing of normal and abnormal mitral annuli. Ann Card Anaesth. 2014, 17:279–283. 10.4103/0971-9784.142062
17. Malik HH, Darwood ARJ, Shaunak S, Kulatilake P, El-Hilly AA, Mulki O, Baskaradas A: Three-dimensional printing in surgery: a review of current surgical applications. J Surg Res. 2015, 199:512–522. 10.1016/j.jss.2015.06.051

Original article
peer-reviewed

### Author Information

###### Ethics Statement and Conflict of Interest Disclosures

Human subjects: Consent was obtained by all participants in this study. The Ethics Application Screening Tool from the Health Research Ethics Authority was utilized to determine if ethics review was required for this project. As the project fit under the following category it was exempt from a review: "Quality assurance and quality improvement studies, program evaluation activities, performance reviews, and testing within normal educational requirements if there is no research question involved (used exclusively for assessment, management or improvement purposes)."

Informed verbal consent was still obtained from participants, and no identifying information was collected. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

###### Acknowledgements

We would like to thank the Clinical Learning and Simulation Centre at Memorial University’s Faculty of Medicine for their support. The work is supported through the MUN MED 3D initiative, and the Teaching and Learning Fund at Memorial University.

Original article
peer-reviewed

6.1