From the Lecture Hall to the Operating Room

Medical technology, computer science, materials science, physics, mathematics – students from a wide variety of majors sit in the packed lecture hall with its ’70s charm. “You won’t graduate from here as medical students, but you should learn something about the anatomy of the brain and the nervous system,” Spetzger tells the audience. Master’s students in Biomedical Engineering have the opportunity to experience the technical systems they know from theory and the lab in practice – in Spetzger’s operating room.

“Neurosurgery is a high-tech discipline. I want to give students a real-world understanding of this technology. In our collaboration with major MedTech companies, we’ve seen that technologies are sometimes developed that are far away from clinical reality and do not work in practice. That’s why it’s important to involve students early on,” says Spetzger.

Preparation Is Everything

The group of students meeting in front of the Neurosurgery Department’s office in May has this opportunity. Sanne, a master’s student in electrical engineering specializing in biomedical engineering, already observed a surgery last winter semester: “Last time, a patient with a pituitary tumor was operated on through the nose. This time, we’ll see how the skull is opened – it’s going to be extremely exciting!”

Before heading into the operating room, Spetzger discusses the case with the group in the neurosurgery library. There’s just enough room for everyone to sit. All eyes are fixed on the large screen displaying numerous radiological images. Dr. Till Brombach, senior physician in neurosurgery at Karlsruhe Neurocenter, presents the case: The patient is 80 years old; the brain tumor is located in front of the motor cortex, is growing rapidly, and is very likely malignant. Without surgery, the woman would die within a few weeks. Upon hearing this diagnosis, the room falls silent for a moment.

“To ensure we know exactly where we are during surgery, we work with MRI datasets that reveal the fine structures of the brain. In addition, we have CT scans that primarily show the bony landmarks. From both datasets, we generate a 3D model in which important areas are marked – a kind of navigation map that makes the procedure faster and more precise.” Uwe Spetzger leans against a cabinet in the background and adds: “Precise planning and intraoperative navigation are the be-all and end-all in neurosurgery. The navigation points used when surgically opening the skull must be as precise as possible so that as little healthy brain tissue as possible is cut through.”

Before heading into the OR, he gives a brief introduction: “You can’t go far wrong – just don’t touch anything and don’t contaminate anything. And if anyone isn’t feeling well, just sit down on the floor – that reduces the distance of a potential fall. While there’s no better place to faint and hit your head than in a neurosurgical operating room, it’s always about minimizing risk.” And with that, the group heads toward the operating room, first through the changing area.

Navigation Accurate to the Millimeter

Wearing green surgical scrubs, surgical caps, masks, and with disinfected hands, everyone is allowed into the area that non-medical staff would normally never enter. The patient is already under anesthesia in the operating room, while every step of the preparation is carried out with practiced precision. Since space is limited, the students are divided into two groups – one group stands in the operating room, while the other observes the procedure through a large glass window.

Brombach explains how the head is secured in a head frame. Attached to it is the reference star, which continuously provides the navigation system with information about the head’s position. This allows the incision points to be precisely determined, and the system also serves as a guide during the operation.

The students are already familiar with the technology from a course module taught by Professor Francesca Spadea, head of the Institute of Biomedical Engineering at KIT, who is also present in the operating room that day. In that module, the students had to program their own navigation system. Using MRI and CT data, they determined the position of a tumor – a simplified version of the system now being used with high precision in the operating room.

Precision Work on a Pulsating Brain

After lengthy preparation, everything happens very quickly: the first incision is made, the skin is opened, three small holes are drilled, and a rounded section of the skull is sawed out. Spetzger positions the surgical microscope over the patient’s head, and after opening the dura mater, the students see the pulsating brain on the screen. No one faints – and Spetzger carefully begins to remove the tumor tissue. Again and again, he places a small ultrasound probe directly on the brain. A new image appears on the screen in real time, showing how far the procedure has progressed. This is because the brain changes during surgery, shifting slightly – and with it, the orientation.
During the surgery, Brombach explains step by step what is happening. A student asks,

“How can you tell during removal which tissue is tumorous and which is healthy?” Brombach replies, “Tumor tissue often differs in color, consistency, and blood supply, but the boundaries are rarely well defined. That’s why, in addition to the surgeon’s experience, we also need the navigation system and ultrasound.”