Cases
Effortless design of a custom preformed titanium membrane
In case of bone tumors the treatment aims at an ideal reconstruction of the weight-bearing bones after tumor resection, which translates as biological affinity, resistance to infection and sufficient biomechanical strength and durability. During surgery, the tumor is excised, while an implant is placed to guarantee the strength of the bone. Such implants can be produced through hydro-forming where a titanium membrane is pressed on a kind of mold. 3-matic software provides the necessary tools for pre-operative planning and the design of the stereolithography master model for casting. Using a digital route - 3-matic - ensures accuracy and results in serious time gains.
Below we describe in more detail how 3-matic facilitates the design of the preformed membrane. It’s the clinical case of an 18-year old male professional swimmer suffering from a juxtacortical chondroma at posterior-medial site of distal femur.
Clear visualization of the tumor
CT images from scanning the patient’s knee were processed with Mimics, resulting in an accurate 3D computer model of the bone. The Mimics model offered a clear visual of the deformed bone (tumor). This model is of great assistance for the pre-operative planning and the design of the implant.
Pre-operative planning in a few minutes
3-matic software’s advanced curve technology allows you to create, select, separate or combine surfaces with ease. This way you can easily select the tumor (Fig. 1: yellow area) that needs to be removed and design the implant. The green area you see in Fig. 1 is the maximum outline of the titanium membrane. This outline is selected in such a way that it ensures a firm fit of the membrane on the remaining bone.
Easy design of the membrane
Next, the surface representing the deformed bone is removed. 3-matic’s innovative surface construction algorithm generates a new surface (Fig. 2: purple area) that reconstructs the original bone shape. The new bone shape is then combined with the outlined surface into the final shape for the membrane. Based on this design the hydroforming tool is created. Using 3-matic the hydro-forming shape (Fig. 3) is designed in less than 10 minutes just by combining the reconstructed bone shape with a cylindrical shape. Next this design is inverted to create a negative 3D model, which will be used for casting.
Cost-efficient, fast manufacturing of custom implant
The negative hydro-forming shape can be produced quickly and cost-efficient using stereolithography. The resulting model is cast to create the hydro-forming tool, which will produce the membrane (Fig. 4).
Successful bone reconstruction surgery
During surgery the tumor is removed according to the pre-operative planning and filling material is placed. After that the membrane is implanted. Thanks to its personalised shape it fits perfectly on the remainder of the bone. This type of implant will provide enough strength for weight bearing applications.
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