The Contribution of Flexible 3D Bone Models for Surgical Training and Planning

Testing Models Across Dozens of Countries

Until recently, the possibilities of 3D printing fracture models were limited to either fixed or dynamic models. While fixed models have all structures firmly connected, dynamic models allow partial separation of individual parts, but without the ability to manipulate bone fragments.

3D fracture models with free fragments do allow manipulation of bone parts but lack realistic connections between the fragments. To address the limitations of existing models, a Swiss research organization specializing in trauma surgery developed new flexible 3D bone models where fragments are connected by small flexible rods called "tentacles." The Swiss team tested these models in collaboration with 133 trauma surgeons from dozens of countries.

Design of the Survey Evaluation

The evaluation of flexible 3D fracture models as an educational tool and aid for preoperative planning was conducted via questionnaires distributed during specialized courses in Germany and Switzerland. The authors of the survey examined whether surgeons found the flexible 3D models beneficial for surgical training, which models were the most useful to them, and whether the new models would assist them in surgical planning.

During the testing of flexible 3D models, properties and behavior of the fragments, durability, tactile feedback, and flexibility were assessed. An integral part of the testing was the evaluation of resistance during drilling, screw application, and durability under repeated handling. Respondents were provided with several models representing various fracture types of the tibia, femur, and humerus.

Major Help in Training and Practice

The first survey involved 32 German surgeons, 60% of whom had over 15 years of experience. Three-quarters of the respondents had previously used 3D models in training, and nearly half in preoperative planning. Most respondents (91%) stated that flexible 3D models would help them during surgical training. In preoperative planning, 83% of surgeons considered the models beneficial.

When comparing the benefits of fixed and flexible 3D models in education, half of the respondents preferred flexible models, while 41% were unsure. In preoperative planning, the preference for flexible models was similar—47%. Uncertainty was expressed by 31% of respondents. Over 80% of surgeons found the flexible 3D models suitable for practicing fracture reduction, and 75% for osteosynthesis. In total, 60% of surgeons considered the evaluated models very realistic.

Second Survey Confirmed the First Results

The second survey involved 101 surgeons from 28 countries. Almost half of them (46%) had over 15 years of experience. Half of the respondents had prior experience with other 3D models. More than 90% of respondents (92% in surgical training and 94% in preoperative planning) found flexible 3D models beneficial.

A significant majority of surgeons (88%) considered flexible 3D models to be a better educational tool than fixed models. Similar results were observed for preoperative planning. The practice of fracture reduction and osteosynthesis using flexible 3D models was deemed appropriate by almost all respondents (98% and 97%, respectively). Over 80% of surgeons described the flexible models as very realistic.

Where Will Further Development Lead?

The survey involving more than 100 trauma surgeons demonstrated the benefits of flexible 3D bone models with fracture fragments for educational purposes and for planning various surgical procedures. The surveyed surgeons prefer flexible models over fixed ones, as they allow better manipulation of individual fragments, support better visualization and tactile feedback, and are sufficiently durable when working with surgical instruments.

According to the survey authors, further development of 3D printing of flexible models could extend to other types of bones and not be limited to long bones only.

Editorial Team, Medscope.pro

Source: Ghidinelli M., Höntzsch D., Atici B., Crespan S. Evaluating the value of 3D-printed bone models with fracture fragments connected by flexible rods for training and preoperative planning. 3D Print Med. 2025 Jan 15; 11 (1): 2, doi: 10.1186/s41205-025-00250-5.