Optimization Of Scaffold Regeneration Process Using Negative Templates Created Using Computer Aided Tissue Engineering 1 Wettergreen MA, 1 Lemoine JJ, 1 Liebschner MAK, 2 Yuksel E 1 Department of Bioengineering, Rice University, Houston, TX 2 Division of Plastic Surgery, Baylor College of Medicine, Houston, TX

Facial Feature Reconstruction Replication of complex geometry current problem Microtia Brent technique Nagata technique Tissue Engineering Scaffold template Implantation of positive template Problems Losing the definition of crevices Composite tissue shape integration Solutions Computer defect modeling Prefabrication / vascularization of feature with negative template

Replication of complex geometry current problem

Microtia

Brent technique

Nagata technique

Tissue Engineering

Scaffold template

Implantation of positive template

Problems

Losing the definition of crevices

Composite tissue shape integration

Solutions

Computer defect modeling

Prefabrication / vascularization of feature with negative template

Computer Aided Tissue Engineering -0.31 0.28 0.79 0.06 % error 19.24 8.40 36.07 54.52 Plaster contralateral ear 19.30 8.37 35.79 54.49 Wax mirrored ear Total Depth of ear (mm) Depth of helix (mm) Width of helix (mm) Total Height of ear (mm)

Prefabrication of Negative Template Provides mechanical protection during tissue regeneration Allows protection of the surface geometry during revascularization/prefabrication process without excess force that can cause additional resorption Allows construction of composite, multilayered implant Forces tissue growth into specific geometric configuration, visible through implant Plaster replica Adjusted computer model Silicon negative

Provides mechanical protection during tissue regeneration

Allows protection of the surface geometry during revascularization/prefabrication process without excess force that can cause additional resorption

Allows construction of composite, multilayered implant

Forces tissue growth into specific geometric configuration, visible through implant

Case Report First stage Temporal incision Harvesting of ipsilateral costal cartilage / PTFE helix TPF flap elevated and laid along contours of mold Cartilage grafts placed along dominant contours of mold Fibrin glue and morselized cartilage used to fill mold to level surface Suction is applied through the mold to force the fascia into the contours Second stage Tpf flap in mold is exposed Well vascularized ear viewed Skin graft placed over implant Implant localized in position of contralateral ear Lobule transposed Fresh mold placed over ear to protect while regeneration

First stage

Temporal incision

Harvesting of ipsilateral costal cartilage / PTFE helix

TPF flap elevated and laid along contours of mold

Cartilage grafts placed along dominant contours of mold

Fibrin glue and morselized cartilage used to fill mold to level surface

Suction is applied through the mold to force the fascia into the contours

Second stage

Tpf flap in mold is exposed

Well vascularized ear viewed

Skin graft placed over implant

Implant localized in position of contralateral ear

Lobule transposed

Fresh mold placed over ear to protect while regeneration

Post Op – 3 weeks Implant well vascularized Inflammation due to hair Satisfactory contouring of tissue to the mold Additional stage required to rotate ear into position

Implant well vascularized

Inflammation due to hair

Satisfactory contouring of tissue to the mold

Additional stage required to rotate ear into position

Conclusions Computer modeling combined with imaging techniques generates exact model of features Prefabrication with negative mold prevents material property inconsistencies which can result in suboptimal 3D contour deficiencies Composite tissue prefabrication overcomes the cartilage engineering resorption problem Future Directions Histology still in process Optimization of the matrix with native cartilage ECM + cell expansion (in non-stress bearing regions) Design of suction system Improvement of 3D contouring of the negative mold

Computer modeling combined with imaging techniques generates exact model of features

Prefabrication with negative mold prevents material property inconsistencies which can result in suboptimal 3D contour deficiencies

Composite tissue prefabrication overcomes the cartilage engineering resorption problem

Future Directions

Histology still in process

Optimization of the matrix with native cartilage ECM + cell expansion (in non-stress bearing regions)

Design of suction system

Improvement of 3D contouring of the negative mold