Biomedical subjects

Paul Alfred Grützner

Publications and source records attributed to Paul Alfred Grützner.

3 recordsLinked to original sources

PubMed2005

Computer-assisted LISS plate osteosynthesis of proximal tibia fractures: feasibility study and first clinical results.

Fluoroscopy is the most common tool for the intraoperative control of long-bone fracture reduction. Limitations of this technology include high radiation exposure for the patient and the surgical team, limited visual field, distorted images, and cumbersome verification of image updating. Fluoroscopy-based navigation systems partially address these limitations by allowing fluoroscopic images to be used for real-time surgical localization and instrument tracking. Existing fluoroscopy-based navigation systems are still limited as far as the virtual representation of true surgical reality is concerned. This article, for the first time, presents a reality-enhanced virtual fluoroscopy with radiation-free updates of in situ surgical fluoroscopic images to control metaphyseal fracture reduction. A virtual fluoroscopy is created using the projection properties of the fluoroscope; it allows the display of detailed three-dimensional (3D) geometric models of surgical tools and implants superimposed on the X-ray images. Starting from multiple registered fluoroscopy images, a virtual 3D cylinder model for each principal bone fragment is constructed. This spatial cylinder model not only supplies a 3D image of the fracture, but also allows effective fragment projection recovery from the fluoroscopic images and enables radiation-free updates of in situ surgical fluoroscopic images by non-linear interpolation and warping algorithms. Initial clinical experience was gained during four tibia fracture fixations that were treated by LISS (Less Invasive Stabilization System) osteosynthesis. In the cases operated on, after primary image acquisition, the image intensifier was replaced by the virtual reality system. In all cases, the procedure including fracture reduction and LISS osteosynthesis was performed entirely in virtual reality. A significant disadvantage was the unfamiliar operation of this prototype software and the need for an additional operator for the navigation system.

Adult↗

PubMed2004

Computer aided long bone fracture treatment.

Intraoperative fluoroscopy is the tool for intraoperative control of long bone fracture reduction and osteosynthesis. Limitations of this technology include: High radiation exposure to the patient and the surgical team, limited field of view, image distortion, limitation to 2-D representations, and cumbersome updating of verification images. Fluoroscopy based navigation systems partially address these limitations by allowing fluoroscopic images to be used for real-time surgical localization and instrument tracking. In a clinical study on computer guidance by virtual fluoroscopy for distal locking, the capability to provide online guidance with significantly reduced fluoroscopy times is demonstrated. Virtual fluoroscopy applied for guidewire placement in a laboratory setup demonstrated the potential of the method to reduce procedure times, and the potential to increase precision of implant placement with decreased fluoroscopy times. By using virtual reality enhancement, starting from multiple registered fluoroscopy images, a virtual 3-D cylinder model for each principal bone fragment is reconstructed. This spatial cylinder model is not only used to supply a 3-D image of the fracture, but also allows effective fragment projection extraction from the fluoroscopic images and further achieves radiation-free updates of in-situ surgical fluoroscopic images through a non-linear interpolation and warping algorithm. After primary image acquisition, the image intensifier was replaced by the virtual reality system. It was shown that all the steps of the procedure, including fracture reduction and LISS osteosynthesis can be performed completely in virtual reality.

Fluoroscopy↗

PubMed2004

Joint replacement-total hip replacement with CT-based navigation.

UNLABELLED: Correct orientation of the cup optimizes the range of motion of total hip arthroplasty (THA) and reduces the risk of dislocation, wear, impingement,and pelvic osteolysis. Therefore, CT-based navigation is used to position the acetabular cup precisely in a planned orientation relative to predefined bony landmarks in order to increase the function and longevity of THA. METHODS: Fourteen patients were operated on using CT-based navigation for acetabular cup positioning. After scanning the patient's pelvis in a preoperative CT, a3-D plan was developed before surgery. Intraoperatively, the CT/3-D model is registered to coincide with the actual position of the patient on the operating table. RESULTS: Mean time for surgery increased by an average of 46 minutes and mean blood loss increased by 140 ml. Positioning of the cup was optimized, ie, it was close to the predefined target. There were no complications related to the use of CT-based navigation. Due to some technical failures at the beginning, two operations were completed manually. CONCLUSION: CT-based navigation greatly enhanced the precision of cup positioning,thus eliminating malpositioning. Although CT-based navigation does support the surgeon in controlling cup orientation, it increases time for surgery, blood loss, radiation of the patient, and total costs of the whole procedure. Furthermore,navigation of the acetabular cup alone is not sufficient for optimizing the range of motion in THA.

Aged↗