A visit to surgeon Dr Metzger

Medical imaging produces an enormous amount of data used in diagnostics and for surgery planning. Professor Marc Metzger works with shape modelling daily.

Seen from today, older methods of data processing were time-consuming and heavy-handed.

Shape models help to address the problem efficiently and with high accuracy, as they allow taking into account statistical data of a given population.

In our first case, Patient X has suffered a trauma. Professor Metzger needs to design an implantable metal plate that immobilises the fracture site while it heals. He imports data belonging to this patient from the so-called PACS. The acronym stands for the Picture Archiving and Communication System of the hospital. Professor Metzger uploads the data to a portal where it is rendered as a visualisation in three dimensions.

The doctor places landmark points on the model, distorting it as he adjusts it to the patient’s needs.

The system corrects the distortion, taking into account the statistical distribution of the given shape in a database of representative samples. Thus the accuracy of the model is improved.

Professor Metzger then designs a metal plate to fix the fracture. He then orders the implantable plate from the lab.

In this way, statistical shape modelling helps to improve the accuracy of a given implant. It has also speeded up the procedures in preparation for a surgery.

The next case shows how Professor Metzger can do even more, preparing a custom designed splint for a patient.

In this case, the patient suffers from dysgnathia, a conspicuous abnormality extending to the jawbones. Again, Professor Metzger imports data from the Picture Archiving and Communication System. This time, he performs a second import from the 3D surface scanner used for measuring the patient. He then fuses the images of these two data sets. In the next step, the model showing the deformed jaw is segmented. The segments are then brought into the corrected position, as they will be during surgery.

Professor Metzger imports the template of the dental splint that will fix the segments to support healing and exports all information.

In the next step, the splint will be adjusted and designed anew.

The shape is then sent to the 3D printer.

The surgical support is produced directly in the doctor’s office.

As these two cases show, statistical shape modelling has become an efficient tool for doctors. It is cost efficient and effective, as it allows adapting devices to a given patient in a short time. It also helps to prepare surgery accurately.

With 3D printing technology on the rise, the care of patients will benefit immensely from modelling.