3D Printing for Complex Cranial Education: Skull Base Tumor Case Illustrations

Introduction: Skull base operations demand a disciplined mastery of neuroanatomy. Although a wide swath of traditional resources have been developed to assist trainees in studying the skull base, translational education from the pages of the atlas to the operating microscope remains a challenge particularly given that most skull base operations involve delicate neurovascular structures, and therefore risk of significant morbidity. Cadaver-based training has traditionally provided the bedrock for developing familiarity with skull base neuroanatomy and technique; however, cadaver dissection is resource intensive, and while it can provide insight regarding normal anatomy, the considerations of complex skull base pathology are not always made clear by the combination of normal cadaveric specimens combined with 2D images. Correspondingly, our goal was to identify and 3D print selected uncommon skull base tumor cases to provide an educational supplement designed to help teach the principles of neuroanatomy as applied to operative approach planning.

Methods: Retrospective series of skull base tumor cases selected for 3D printing as illustrative examples of major approaches and pathologies. Segmentation was performed using Mimic software package; models were subsequently printed on a multilateral multicolor Objet 500 and a multicolor single material ProJet 660. Trainees were serially presented imaging studies followed by 3D-printed models and surveyed regarding understanding of key anatomic relationships and recommended skull base approaches for each pathology.

Results: Eight skull base tumor cases were 3D printed and included in the study. Three had undergone an orbitozygomatic craniotomy for mature teratoma, desmoid, and malignant solitary fibrous tumor; one had a middle fossa craniotomy for resection of a tenosynovial giant cell tumor; one had undergone a retrosigmoid craniotomy for an exophytic juvenile pilocytic astrocytoma; one had undergone an endoscopic endonasal resection of a calcifying pseudoneoplasm of the neuraxis; and one underwent an orbital craniotomy for adenoid cystic carcinoma. Residents surveyed indicated a significant improvement in understanding of 3D neuroanatomic relationships and principles of approach selection after having seen the printed models, as compared with 2D imaging alone.

Conclusion: 3D printing is an emerging technology with the potential to transform neuroanatomy education by combining key features of cadaver dissection such as the ability to observe and integrate multiple 3D relationships simultaneously, while preserving the patient- or disease-specific anatomic alterations induced by pathology. Our preliminary results suggest that trainees may benefit significantly from the development of a formal skull base curriculum built around models of common tumor pathologies and operative approaches. Prospective study in a larger cohort is required to better assess the pedagogical potential of an integrated 3D printing neuroanatomy curriculum as an adjunct to traditional cadaver and radiology based training models.