Quantitative Computerized Assessment of the Degree of Acetabular Bone Deficiency: Total radial Acetabular Bone Loss (TrABL)

A novel quantitative, computerized, and, therefore, highly objective method is presented to assess the degree of total radical acetabular bone loss. The method, which is abbreviated to “TrABL”, makes use of advanced 3D CT-based image processing and effective 3D anatomical reconstruction methodology. The output data consist of a ratio and a graph, which can both be used for direct comparison between specimens. A first dataset of twelve highly deficient hemipelves, mainly Paprosky types IIIB, is used as illustration. Although generalization of the findings will require further investigation on a larger population, it can be assumed that the presented method has the potential to facilitate the preoperative use of existing classifications and related decision schemes for treatment selection in complex revision cases

A custom-made guide-wire positioning device for Hip Surface Replacement Arthroplasty: description and first results

<p>Abstract</p> <p>Background</p> <p>Hip surface replacement arthroplasty (SRA) can be an alternative for total hip arthroplasty. The short and long-term outcome of hip surface replacement arthroplasty mainly relies on the optimal size and position of the femoral component. This can be defined before surgery with pre-operative templating. Reproducing the optimal, templated femoral implant position during surgery relies on guide wire positioning devices in combination with visual inspection and experience of the surgeon. Another method of transferring the templated position into surgery is by navigation or Computer Assisted Surgery (CAS). Though CAS is documented to increase accurate placement particularly in case of normal hip anatomy, it requires bulky equipment that is not readily available in each centre.</p> <p>Methods</p> <p>A custom made neck jig device is presented as well as the results of a pilot study.</p> <p>The device is produced based on data pre-operatively acquired with CT-scan. The position of the guide wire is chosen as the anatomical axis of the femoral neck. Adjustments to the design of the jig are made based on the orthopedic surgeon's recommendations for the drill direction. The SRA jig is designed as a slightly more-than-hemispherical cage to fit the anterior part of the femoral head. The cage is connected to an anterior neck support. Four knifes are attached on the central arch of the cage. A drill guide cylinder is attached to the cage, thus allowing guide wire positioning as pre-operatively planned.</p> <p>Custom made devices were tested in 5 patients scheduled for total hip arthroplasty. The orthopedic surgeons reported the practical aspects of the use of the neck-jig device. The retrieved femoral heads were analyzed to assess the achieved drill place in mm deviation from the predefined location and orientation compared to the predefined orientation.</p> <p>Results</p> <p>The orthopedic surgeons rated the passive stability, full contact with neck portion of the jig and knife contact with femoral head, positive. There were no guide failures. The jig unique position and the number of steps required to put the guide in place were rated 1, while the complexity to put the guide into place was rated 1-2. In all five cases the guide wire was accurately positioned. Maximum angular deviation was 2.9° and maximum distance between insertion points was 2.1 mm.</p> <p>Conclusions</p> <p>Pilot testing of a custom made jig for use during SRA indicated that the device was (1) successfully applied and user friendly and (2) allowed for accurate guide wire placement according to the preoperative plan.</p

Automated osteotomy simulation for craniosynostosis surgery

Mommaerts M., Clijmans T., Suetens P., Vander Sloten J., ''Automated osteotomy simulation for craniosynostosis surgery'', 7th Asian Pacific Craniofacial Association conference, October 5-8, 2008, Taipei, Taiwan.status: publishe

Computer supported pre-operative planning of craniosynostosis surgery: a mimics-integrated approach

Clijmans T., Gelaude F., Mommaerts M., Suetens P., Vander Sloten J., ''Computer supported pre-operative planning of craniosynostosis surgery: a mimics-integrated approach'', Annual medical innovations conference - Materialise Mimics Innovation Awards 2006, May 27, 2006, Barcelona, Spain.status: publishe

Computer-based planning method for shape reconstruction of severely damaged glenoids using CT data

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CT-based virtual shape reconstruction for severe glenoid bone defects

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