  Given the multitude of challenges surgeons face during mitral valve repair
surgery, they should have a high confidence in handling of instruments and in
the application of surgical techniques before they enter the operating room.
Unfortunately, opportunities for surgical training of minimally-invasive repair
are very limited, leading to a situation where most surgeons undergo a steep
learning curve while operating the first patients. In order to provide a
realistic tool for surgical training, a commercial simulator was augmented by
flexible patient-specific mitral valve replica. In an elaborated production
pipeline, finalized after many optimization cycles, models were segmented from
3D ultrasound and then 3D-printable molds were computed automatically and
printed in rigid material, the lower part being water-soluble. After silicone
injection, the silicone model was dissolved from the mold and anchored in the
simulator. To our knowledge, our models are the first to comprise the full
mitral valve apparatus, i.e. the annulus, leaflets, chordae tendineae and
papillary muscles. Nine different valve molds were automatically created
according to the proposed workflow (seven prolapsed valves and two valves with
functional mitral insufficiency). From these mold geometries, 16 replica were
manufactured. A material test revealed that Ecoflex\textsuperscript{TM} 00-30
is the most suitable material for leaflet-mimicking tissue out of seven
mixtures. Production time was around 36h per valve. Twelve surgeons performed
various surgical techniques, e.g. annuloplasty, neo-chordae implantation,
triangular leaflet resection and assessed the realism of the valves very
positively. The standardized production process guarantees a high anatomical
recapitulation of the silicone valves to the segmented models and the
ultrasound data...
