Safe spinal surgery
Spinal fusion is sometimes the only treatment that offers lasting relief to patients suffering from severe back pain. At Balgrist University Hospital in Zurich, Tobias Götschi is developing a method to make the procedure safer. His work is made possible thanks to a MedTech Entrepreneur Fellowship.
Back pain is widespread in modern society. According to Switzerland’s association for the prevention of rheumatic disorders (Rheumaliga), about half the population report that they regularly experience back pain. While acute symptoms normally subside within a few weeks, about thirty percent of all patients develop chronic pain, which often has its roots in a sedentary lifestyle, desk jobs or heavy lifting. Being overweight is another factor that accelerates degeneration of spinal discs and vertebrae.
The most effective treatments for degenerative spinal conditions are physiotherapy, dietary changes and increased physical activity. If these fail to bring about improvements, a surgical intervention—on a herniated disc, for example—is generally the next step. In some cases, however, even surgery fails to stabilise the spine, and patients continue to experience pain or other negative symptoms.
“Often, the only remaining option for these patients is a spinal fusion,” Tobias Götschi explains. “In this procedure, the problem vertebrae are fused together to immobilise them, which relieves pressure and alleviates pain.” Götschi, who earned his PhD at the ETH Zurich Institute for Biomechanics two years ago, is now project leader in the Spine Biomechanics group at Balgrist University Hospital, where he studies the biomechanical processes involved in spinal fusion.
Risky surgery
In 2024, Götschi was awarded a University of Zurich MedTech Entrepreneur Fellowship to develop his “SpinePlanner”, a preoperative planning platform designed to optimise spinal fusion operations. The Werner Siemens Foundation funds the Fellowship programme, which was created to support young researchers in translating their research findings into marketable products and services. Each Fellowship comprises a grant of 150,000 Swiss francs as well as access to state-of-the-art infrastructure, coaching and networking opportunities.
To understand how Tobias Götschi’s idea works, it’s first necessary to grasp the basics in spinal fusion. In most cases, surgeons insert pedicle screws made of titanium into the vertebrae and connect them with metal rods, which are bent so that the vertebrae are fastened together at the correct angle. Over time, the connected vertebrae grow together to form a single bone.
“Spinal fusions are generally very successful,” Götschi says. Nevertheless, he continues, complications can arise, with pedicle screw loosening being one of the biggest problems. The titanium screws must be able to withstand high loads; however, the screws tend to loosen easily when the bone mass of vertebrae is brittle, as is the case in patients with osteoporosis.
Simulating risk
“If this happens, patients experience pain and a follow-up surgery may become unavoidable,” Götschi says. Past studies have shown that the pedicle screws loosen in up to sixty percent of patients with osteoporosis. In the US alone, this generates additional healthcare costs upwards of seven hundred million dollars.
Surgeons have various options to prevent pedicle screws from loosening, including bone cement they apply directly through tiny openings in the hollow screws. The cement flows through the hollow screw and into the surrounding bone, greatly increasing fixation stability. The drawback to this solution is that bone cement is expensive—and not entirely risk-free. For instance, if the liquid mass leaks into the bloodstream before hardening, it can cause embolisms.
Given the risks, it’s crucial that surgeons make an accurate assessment of when bone cement can be used safely and effectively in spinal fusion—and when not. “Until now, surgeons have only had their own experience to rely on when making these decisions,” Götschi says. And this is where SpinePlanner comes in. His solution is a CT-based simulation platform that builds patient-specific models, tests different surgical options and quantifies the resulting construct strength.
“We use these data to predict the likelihood of pedicle screw loosening for each option,” Götschi explains. This means the platform enables surgeons to gauge the exact placement and angles for the pedicle screws to maximise stability—while also avoiding close proximity to sensitive anatomy.
Boosting stability
In a recent study, Götschi and his team demonstrated that SpinePlanner offers considerable advantages. They had surgeons insert standard, clinically approved metal screws into human donor tissue, then compared the results with those generated by the SpinePlanner algorithm. They found that planning with the new platform boosts screw stability by forty-two percent. Götschi says this represents a huge improvement. By comparison, the development of the latest, state-of-the-art titanium screws increased stability by a mere five percent.
SpinePlanner has yet to receive approval for use in planning surgical interventions. “However, our technology is already at a fairly advanced stage, and we’re in close contact with several interested parties,” Götschi says, adding that the MedTech Entrepreneur Fellowship is what has given him the time and resources to seek partners and hold discussions. “In addition the networking events and coaching sessions have helped me learn how to build a medtech software business and protect my technology.”
Although Tobias Götschi could easily try to market his platform directly to hospitals or clinics, he has chosen a different route. Instead, he plans to licence his product to larger companies that will then integrate SpinePlanner into their larger surgical planning platforms. It will be interesting to see who opts for the innovative tool—and when surgeons and patients will be able to benefit from the technology.
