 BACKGROUND: A young motor cyclist with a history of several wrist surgeries: first, a left-sided scapholunate ligament repair, reoperated with a ligament reconstruction, and later with a four-corner fusion (4CF). One-year after the 4CF, the CT images showed a remaining scaphoid, misplaced screws in the lunotriquetral joint, screw fractures of the lunate, and pseudoarthrosis of the 4CF. In a fourth wrist surgery the scaphoid was removed, the pseudoarthrosis areas were treated with bone grafts, and a new implant was placed. However, two years after 4CF the patient suffered from diffuse radial wrist pain, mainly upon loading, and the CBCT images lead us to suspect partial non-union. EXAMINATION: A CBCT kinematic study in flexion, extension, and neutral position was performed as well as an assessment of ossification to rule out non-union as a cause of wrist pain. The CBCT images were sent to Disior™ for further kinematics analysis. The results of the custom kinematic analysis of the 4CF are shown in Table 1. When comparing the capitolunate angle in neutral position and in flexion, there was a 9-degree difference in motion. Similarly, the lunotriquetral angle in neutral and extended position showed a 12-degree difference. Moreover, a rotation and translation analysis was performed to investigate how the other carpal bones moved compared to the lunate during motion. This analysis showed rotation around the flexion-extension motion axis (sagittal), as well as translation towards volar direction for all other carpal bones. A flexion-extension motion analysis of the lunate and the capitate revealed that motion occurred between these carpal bones. The custom ossification analysis confirmed the non-fusion of the previous 4CF as shown in Figure 1. TREATMENT: Based on these findings, a new 4CF with complete debridement of the joint, bone grafting, and placement of more solid cannulated screws was performed. “The kinematic analysis, performed as an in-house service by Disior, enabled us to plan personalized surgical treatment in this complex case of a failed four corner fusion."  Table 1. Inter-axis angles during flexion-extension poses.  Figure 1. Level of ossification measured by assessment of radiodensity values (Hounsfield Units, HU), showed lower values across joint gaps.  BACKGROUND: A patient with osteoarthritis in need of a supramalleolar osteotomy to improve mobility and quality of life. OPERATIVE PLAN: Assessment of the patients’ preoperative pathology was performed by analyzing their CBCT data in Bonelogic™ Foot & Ankle module. The medial distal tibial angle (MDTA) and the tibial lateral surface angle (TLSA) were 85.5° and 93.7°, respectively. A corrective supramalleolar osteotomy was planned using the Planning module of Bonelogic™. The simulation predicted that using a 14 mm saw with 0.4 mm thickness to create a wedge opening (of 8.72° and 5 mm wide), 20 mm from the tibial plafond to a depth of 31 mm, would result in an increase in the MDTA of 9.0° and a reduction of TLSA of 2.8°. A surgical guide was manufactured and used in accordance with these parameters:  Summary of the key parameters from the analysis of the patient data and surgical plan.
Disior’s Bonelogic™ medical imaging software, was built specifically to help clinicians make diagnoses and plan patient treatment. Bonelogic anatomical modules take DICOMs from CT, CBCT or WBCT and generates accurate models and analytics that describe the relationships between bones, like those used in this case study. The new Planning module, allows you to use these diagnostics to plan precise and effective treatments, through the creation of numerical plans and 3D-printed surgical guides (via third parties).
If you're interested in learning how Disior's products can aid in your clinical practice, talk to one of our experts. In a 30 minute meeting we can talk through your current image analysis workflow and discuss what we can do to improve patient outcomes together.   Dr Philipp Honigmann is a Hand surgeon and an active clinical researcher. He has been publishing on the use of 3D printing in clinical practices since 2017. He is the team leader of Hand surgery at the Kantonsspital Baselland in Switzerland, co-Leader of Swiss Medical Additive Manufacturing Research Group University of Basel, and Board Member of the Swiss Society for Surgery of the Hand SSSH, SGH, SSCM and of the Swiss College of Surgeons.
VERIFICATION OF PRELIMINARY RESULTS The additional analysis of the cone-beam computer tomography (CBCT) images facilitated by the Bonelogic™ 2 software enabled 3D visualization, automated measurements, and distance mapping that helped us assess the bone-to-bone distance in detail. The virtual osteotomy tool of Bonelogic™ 2 allowed us to simulate the post-operative outcome after a 14.7° rotation of the radius as planned. The bone-to-bone distance mapping revealed an overload on the dorsal surface of the sigmoid notch (Figure 2).  Figure 2 Distance mapping performed with the Bonelogic® 2.0 to quantify the simulated post-operative outcome after performing a 14.7° rotation. ALTERNATIVE OPERATIVE PLAN The simulation of the post-operative outcome shown above suggested that a different surgical approach was more appropriate and lead us to perform a de-rotation and shortening of the ulna using patient-specific guides and a standard plate. PRELIMINARY RESULTS Six weeks after the osteotomy, we used the distance mapping in Bonelogic™ 2 again to assess the post-operative outcome (Figure 3). The patient reported symptom relief and improved functionality in the hand. The additional information provided by Bonelogic™ 2 and the virtual surgical planning in the software helped guiding the choice of surgical approach in this complex case and facilitated providing the patient with the best possible treatment.  Figure 3. Distance mapping performed with the Bonelogic™ 2 to assess the post-operative outcome six weeks after corrective osteotomy. Thank you for taking the time to read this case study.
Disior™ Bonelogic™ was built specifically to help clinicians make diagnoses and plan patient treatment. Bonelogic™ takes DICOMs from CT, CBCT or WBCT and generates accurate models and analytics that describe the relationships between bones, like those used in this case study. If you're interested in learning how Disior's products can aid in your clinical practice, talk to one of our experts. In a 30 minute meeting we can talk through your current image analysis workflow and discuss what we can do to improve patient outcomes together. 
“It was one of these subtle cases and I needed to get an accurate 3D model and distance map to see how to approach this patients’ treatment." - François Lintz, MD.  The accurate 3D models, revealed a very subtle but asymmetrical TMT1 arthritis on the left foot, where the metatarsal had slipped on the cuneiform (Figure 1).  Figure 2. Right-left comparison of TMT1 joint space. By comparing the joint spacing between the left and right TMT1 you can see the subtle narrowing of the left TMT1 joint indicative of arthritis (Figure 2). Figure 3. Video of the distance mapping of the Lisfranc area. Distance mapping of the Lisfranc region (Figure 3) showed subluxation and approximation in the dorsal aspect of the joint explaining the patient's pain. These insights allowed Dr Lintz to choose the most appropriate treatment, firstly a pair of supporting insoles, then a TMT1 fusion. “This case clearly illustrates why Disior’s software is a game changer for common foot problems." |
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Disior™ Bonelogic™ was built specifically to help clinicians make diagnoses and plan patient treatment. Bonelogic™ takes DICOMs from CT, CBCT or WBCT and generates accurate models and analytics that describe the relationships between bones, like those used in this case study.
If you're interested in learning how Disior's products can aid in your clinical practice, talk to one of our experts. In a 30 minute meeting we can talk through your current image analysis workflow and discuss what we can do to improve patient outcomes together.
If you're interested in learning how Disior's products can aid in your clinical practice, talk to one of our experts. In a 30 minute meeting we can talk through your current image analysis workflow and discuss what we can do to improve patient outcomes together.
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