How Formlabs 3D Printers Are Helping With Complex Brain Aneurysm Surgeries

Posted by FIT THAI on July 24, 2026

A 3D-printed skull revealing the brain and arteries, used for training in craniotomy.

In recent years, advances in endovascular treatment technology have reduced the necessity for surgical clipping of brain aneurysms. Today, most uncomplicated brain aneurysms are treated with minimally invasive endovascular surgery.

In more complex and severe cases, where intracranial surgery is unavoidable, 3D printing technology has been utilized as a tool for planning and guidance during surgery to reduce risks and improve treatment outcomes.

Dr. Sahin Hanalioglu from the Department of Neurosurgery, Hacettepe University, a leading expert in this field, pioneered the use of 3D-printed models to improve surgical outcomes.

Problem:

The case study below involves a patient with a relatively large brain aneurysm.

An aneurysm is a type of vascular anomaly, a bulge in a blood vessel caused by a weakening of the vessel wall. If a cerebral aneurysm ruptures, it can lead to bleeding in the brain.

Furthermore, if a thrombus forms inside the aneurysm, which is a blood clot obstructing a vein or artery, it can also become a cause of embolic stroke.

Solution:

To isolate this aneurysm from the normal blood circulation of the brain.

Generally, aneurysms are deeply embedded within the brain. To access them, microsurgical techniques are required to carefully separate and dissect the brain fissures or surrounding natural pathways.

In the final step, the aneurysm is isolated from the circulation using a surgical clip and the wound is closed. This surgery is called "aneurysm clipping."

Comparison between traditional methods and 3D printing:

According to traditional methods, neurosurgeons use images from CT or MRI scans, combined with their anatomical knowledge, to visualize the three-dimensional relationship of lesions within the skull.

However, 3D printing technology and 3D visualization make it easy to examine concrete anatomical structures, both on screen via a 3D VR headset and from 3D-printed models.

In recent years, 3D visualization technology has advanced incredibly, but for many surgeons, having actual patient-specific models and being able to practice with them has a much more positive impact on surgical outcomes.

Btech's multi-layered, segmented, and fully integrated 3D models can be beneficial for craniotomy, where surgeons need to drill into the skull and remove a portion to create a "surgical opening" without damaging the underlying tissue.

This unique model not only allows surgeons to visualize structures but also enables them to simulate surgery.

Surgeons have the opportunity to rehearse the surgery and explore different approaches to lesion removal before the actual operation, allowing them to understand the pros and cons of each surgical technique, as well as identify parts that might hinder the surgery.

Specific software for Formlabs printers called "PreForm" is used for part positioning and fabrication.

Crucially, using 3D-printed models allows for increased confidence before complex surgeries. "There are no surprises during surgery, and everything can be rehearsed beforehand. This is beneficial for my own practice and for many surgeons I've spoken with," says Hanalioglu.

Other advantages of 3D printing: 3D-printed models are not only important for patients but also for educating graduate students and students in laboratories. There are various types of radiological modalities, such as MR angiography and 3D volumetric MR venography, which can create complete and intricate models. However, each modality can only visualize one or two specific internal brain structures, such as diencephalic structures or ventricular structures. But when there is a lesion, such as a tumor, the brain's structure undergoes anatomical changes or displacement. Therefore, it is necessary to re-image and reconstruct the normal tissue structure according to the type of lesion. 3D-printed models are patient-specific and disease-specific, and are completely personalized," says Hanalioglu.

Hanalioglu states, "In complex surgeries, sometimes only the chief surgeon can fully understand where the patient's problem lies." "Now, with 3D-printed models, everyone, including residents, can enter surgery with knowledge, making intraoperative guidance easier."

He further adds, "These 3D-printed models are useful for rehearsing surgeries with residents, students, and other colleagues." "Having 3D-printed models helps in training medical students, residents, and junior neurosurgeons, as well as facilitating discussions about surgery," says Hanalioglu.

In the image on the right, different modalities show different aspects of a single reality, which is this three-dimensional pathology. However, with a 3D-printed model, these disparate pieces of information are integrated into a single whole. On the left is an intraoperative image.

Method for creating 3D models:

Btech uses Materialise or Mimics software to segment the models. Biomedical engineers use this software to import individual DICOM files acquired with different modalities.

The segmentation, modeling, and simulation processes are performed using the software's functions, and the final files are exported in .stl or .obj format.

Surgeons can participate in this process to help clarify the pathology and fine-tune the final digital file for fabrication. For example, surgeons can identify overlapping or interfering blood vessels and use their expertise to cross-check each model.

Even with high-resolution imaging technology, for such complex systems, a second opinion is crucial.

Patient's perspective:

A 55-year-old patient experiencing seizure-like symptoms was analyzed, starting with brain imaging using CT and MRI scans.

Brain imaging revealed a 1.5 cm mass in the left Sylvian fissure, between the frontal and temporal lobes. Initially, it was suspected to be a large tumor or an aneurysm.

After further imaging diagnostics, it was confirmed to be a large, thrombosed aneurysm, measuring 2 cm or more.

When a thrombus is found within an aneurysm, small, dense clots can detach and travel to distal arteries, causing arterial occlusion. Such blockages interrupt blood flow to critical parts of the brain, leading to stroke.

When surgical treatment was proposed as an option, the medical team used digital models from advanced imaging diagnostics such as CT, MR, MR Angiography, and 3D rotational digital subtraction angiography to discuss the surgical plan with the patient.

In acute cases requiring urgent surgery, as in this instance, the use of 3D models facilitates visualization, enables rehearsal, and helps patients understand and accept the procedure before surgery.

As can be seen from digital simulations, the color, angle, and position of digital models can be changed to simulate the appearance of the final surgery.

This image demonstrates the complex relationship between the central prism and the underlying blood vessels. This model allows surgeons to examine the relationship between the main branches of the subcortical vessels and simulate aneurysm clipping before surgery.

As a result, surgeons can easily obtain visual information during surgical preparation, leading to more effective surgery.

Challenges and considerations:

A drawback of 3D printing is the time required to create parts. Hanalioglu states that preparing and printing models takes one to two days or more. Therefore, in very urgent cases, 3D models may not be feasible.

Surgeons also need to ensure they have appropriate equipment, such as high-resolution scanners and high-quality 3D printers.

According to Hanalioglu, the most important features to consider when choosing a 3D printer are:

Ability to print both hard and soft materials, as his models include both skull and arteries.
Parts must have high resolution, which is crucial for simulating surgery as realistically as possible.
The cost per part must be reasonable.

3D Printing, cadavers, and surgical planning:

Most doctors accept 3D-printed models as supplementary tools, not as replacements for cadavers.

However, studies and practices relying solely on cadavers have limitations, and research institutions are increasingly using 3D-printed models to fill knowledge gaps at a lower cost.

In cases where resident groups are overcrowded, instructors cannot teach each student using a cadaver.

"So, we teach the basics using cadavers, and practice more detailed procedures using 3D-printed models. Of course, we can also adjust the details of 3D-printed models according to the level of medical students. For example, coloring parts of the model is beneficial for new students," says Hanalioglu.

Therefore, for maximum value in medical education, a coordinated use of both 3D-printed models and cadavers is necessary.

An advantage of 3D-printed models is the transparency of the brain, allowing easy visualization of aneurysms and blood vessels located beneath the temporal and frontal lobes.

Compared to digital 3D models, the importance of physical 3D-printed models becomes clearly evident in cases where surgeons lack sufficient experience to handle the surgery.

3D-printed models help less experienced surgeons to precisely locate aneurysms and standardize craniotomy approaches.

Digital 3D models can be virtually repositioned and segmented, but they lack haptic feedback.

With 3D-printed models, surgeons can manually reposition the model to view the brain from different angles. However, once the model is damaged or cut, it cannot be restored.

Materials used for 3D-printed models:

For this 3D-printed model, anatomical data of cerebral blood vessels, tissues, and skull were collected from imaging.

Durable Resin was used to print the bone model, and Elastic 50A Resin was used to print brain tissue and blood vessels.

This model was printed on a Form 3 machine, but has recently transitioned to a Form 3B+ machine.

Hanalioglu uses the elastomeric properties of Elastic 50A because it can mimic arterial tissue, allowing for accurate practice.

He says, "In recent years, materials have improved, allowing for a tactile sensation much closer to that of arteries. While there's still room for improvement, the haptic feedback is better than before."

Finally, Hanalioglu states, "We paint the printed arterial models to help distinguish different parts. The ability to paint on soft materials like Elastic 50A Resin is another advantage of this material."