Eero Huotilainen1, Mika Salmi2, Jan Lindahl3. 1. School of Engineering, Aalto University, Espoo, Finland. Electronic address: eero.huotilainen@aalto.fi. 2. School of Engineering, Aalto University, Espoo, Finland. 3. Helsinki University Central Hospital, Helsinki and Uusimaa Hospital District, Helsinki, Finland.
Abstract
BACKGROUND: The fit of the allograft is a particular concern in fresh cadaveric osteochondral allograft (FOCA) surgery. Digital design and fabrication were utilized in conjunction with traditional surgery to enable efficient discovery and reproduction of appropriately dimensioned allograft. METHODS: A patient with large osteochondral defects in the lateral femoral condyle was to undergo FOCA surgery. A digital virtual operation was performed, based on computed tomography (CT) images of the patient. Polyamide saw templates were manufactured using a selective laser sintering process, and gypsum powder was used to manufacture preoperative and intraoperative medical models with binder jetting process. The design dimensions were verified numerically by determining the intactness of the section surface and allograft volume based on four independent measurements of the initial design, and an automated design optimization strategy was postulated. For the surgery, a lateral longitudinal approach was employed. RESULTS: The virtual operation allowed an efficient design of the saw templates. Their shape and dimensions were verified with a numerical CT analysis method. The allograft dimensions (medial-lateral/superior-inferior/anterior-posterior) were approximately 40/28.5/24 mm, respectively, with the anterosuperior corner diagonally removed, yielding a section volume of approximately 16.5 cm3. These manually chosen dimensions were reminiscent of the corresponding computationally optimized values. CONCLUSIONS: Use of computer-aided design in virtual operation planning and three-dimensional printing in the fabrication of designed templates allowed for an efficient FOCA procedure and accurate allograft fitting. The numerical optimization method allowed for a semiautomated design process, which could in turn be realized also with surgical navigation or robotic surgery methods.
BACKGROUND: The fit of the allograft is a particular concern in fresh cadaveric osteochondral allograft (FOCA) surgery. Digital design and fabrication were utilized in conjunction with traditional surgery to enable efficient discovery and reproduction of appropriately dimensioned allograft. METHODS: A patient with large osteochondral defects in the lateral femoral condyle was to undergo FOCA surgery. A digital virtual operation was performed, based on computed tomography (CT) images of the patient. Polyamide saw templates were manufactured using a selective laser sintering process, and gypsum powder was used to manufacture preoperative and intraoperative medical models with binder jetting process. The design dimensions were verified numerically by determining the intactness of the section surface and allograft volume based on four independent measurements of the initial design, and an automated design optimization strategy was postulated. For the surgery, a lateral longitudinal approach was employed. RESULTS: The virtual operation allowed an efficient design of the saw templates. Their shape and dimensions were verified with a numerical CT analysis method. The allograft dimensions (medial-lateral/superior-inferior/anterior-posterior) were approximately 40/28.5/24 mm, respectively, with the anterosuperior corner diagonally removed, yielding a section volume of approximately 16.5 cm3. These manually chosen dimensions were reminiscent of the corresponding computationally optimized values. CONCLUSIONS: Use of computer-aided design in virtual operation planning and three-dimensional printing in the fabrication of designed templates allowed for an efficient FOCA procedure and accurate allograft fitting. The numerical optimization method allowed for a semiautomated design process, which could in turn be realized also with surgical navigation or robotic surgery methods.
Authors: Alexandria L Irace; Anne Koivuholma; Eero Huotilainen; Jaana Hagström; Katri Aro; Mika Salmi; Antti Markkola; Heli Sistonen; Timo Atula; Antti A Mäkitie Journal: Int J Environ Res Public Health Date: 2021-01-21 Impact factor: 3.390