Desktop Stereolithography: An Affordable and Time-Efficient Alternative

Background: Three-dimensional printing (3DP) technology has been used in medicine for anatomical modeling, pre-operative planning, prosthetic construction, and most recently bioprinting^1,2.  The high purchase cost of 3D printers has previously limited their widespread use, causing surgeons to outsource 3D anatomic model manufacturing at an average cost of $4,000/print³.  The development of “desktop” 3D printers has decreased printer purchasing cost from $45,000 (2001) to under $2,000 (2016)⁴, providing opportunity to bypass high-cost third-party manufacturing to create patient-customized 3D models.  We provide a proof-of-concept demonstration using a desktop 3D printer and open-access software to create patient-specific computerized tomography (CT)-based 3D models to guide skeletal deformity reconstructions.

Methods: Four patients (2 syndromic craniosynostosis, 1 cranioplasty defect, 1 distal radius deformity secondary to arthrogryposis) were included. CT scans (≤1-mm slices) were obtained (DICOM file format) for volumetric conversion to 3D models (STL file format) using free open-source software (3D Slicer, http://www.slicer.org). The resulting STL files were uploaded to the Cura (Ultimaker, Geldermalsen, Netherlands) desktop application for printing with the BQ Witbox ($1,000, BQ, Madrid, Spain). Material cost and printing time were recorded for comparison to alternative manufacturing methods. The 3D models were used to guide pre-operative planning and intra-operative reconstruction.

Results: CT-to-3D models were successfully printed for all patients. Two distinct 3D models were created for the cranioplasty case (volumetric skeletal reconstruction and topographic representation of the defect). The printing material (polylactic acid) averaged $15/model and its unique properties allowed for inexpensive gas sterilization for intraoperative use. CT-to-3D model conversion time averaged 24-hours/case. All patients underwent successful reconstruction without complications.

Case Example: A 23 month old female with history of ruptured middle cerebral artery aneurysm requiring craniotomy, hematoma evacuation, ventriculoperitoneal shunt placement with resulting 40cm² parietal cranial defect and pseudocyst formation successfully underwent delayed stereotactic pseudocyst drainage and parietal exchange hybrid cranioplasty⁵with particulate bone graft and demineralized bone matrix. 3D models of her neurocranium with the cranial defect and a topographic representation of the defect were created to guide reconstruction

Conclusion: An affordable, user-friendly 3D printer provides a practical, cost-effective, and time-efficient alternative to traditional outsourcing of 3D anatomic model manufacturing. This technology affords reconstructive surgeons the ability to construct realistic, economical 3D models for enhanced pre-operative planning and intra-operative guidance for complex defect reconstruction.