Mimics Innovation Awards 2024 Finalist: Nick Kampkuiper

Our dream, both then and now, is to improve sacroiliac joint fusion (SIJF) using 3D technology to better treat patients suffering from severe pelvic instability. This treatment aims to stabilize the joint by inserting three triangular implants, reducing pain by limiting joint movement. Our goal was to make the placement of these implants more precise and straightforward, thereby lowering the risk of complications and enhancing the procedure’s safety and effectiveness. Additionally, we strived to achieve this in a cost-effective way to ensure the technology remains widely accessible.

SIJF is a procedure often guided by 2D fluoroscopic imaging, which helps visualize the bone during the procedure using X-rays. However, placing the implants correctly without damaging neural structures can be difficult due to anatomical differences, poor visibility on intraoperative imaging, and the lack of 3D spatial information. This makes the procedure challenging and potentially risky. 

While some advanced navigation-guided systems can assist, they are often expensive, not widely accessible, and may extend the duration of the surgery. 

As an alternative, we developed a method called virtual surgical planning (VSP) for SIJF. This involves creating a 3D model of the pelvis from CT scans and virtually placing the implants. VSP helps us understand the anatomy better and plan the optimal implant placement while avoiding critical structures. 

Despite this, translating the 3D implant positions to 2D intraoperative fluoroscopic images was still a challenge. To address this, we used the fluoroscopy module in Materialise Mimics. This module can generate simulated fluoroscopic images of the pelvis with the virtually inserted implants. The surgeon can view these simulated images during the procedure, allowing a more accurate replication of the surgical plan. 

We evaluated the accuracy of implant placement using VSP in SIJF. Ten interventions were performed on ten female patients by the same surgeon, with a total of 30 implants placed. The median age of the patients was 39 years. 

The overall mean placement accuracy of the implants was 4.9 ± 1.26 mm and 4.0 ± 1.44°. Importantly, there were no complications related to malpositioning. VSP provided valuable insights into the anatomy and helped determine the optimal position and length of the implants. The planned implant positions were successfully replicated during surgery, achieving a now seemingly clinically acceptable level of accuracy.

Achieving qualitative outcomes after minimally invasive surgeries near critical anatomical structures continues to be a challenging task in which a wide range of assisting technologies — such as surgical guides, navigation, or robotics — are used to increase the procedures’ safety. This paper highlights this challenge specifically for sacroiliac joint fusion and shows that through the use of Mimics software, the combination of virtual planning and a simulation of the intra-operatively available imaging yields a fairly simple approach that can achieve clinically acceptable accuracy in implant placement. We believe this paper can inspire clinicians to adopt virtual surgical planning for these procedures and encourage researchers to explore using similar simulation approaches in other clinical procedures.