Morris, Jonathan M.

Abstract Background 3D printing—also known as additive manufacturing—has a wide range of applications. Reproduction of low-cost, high-fidelity, disease- or patient-specific models presents a key developmental area in simulation and education research for complex cranial surgery. Methods Using cadaveric dissections as source materials, skull base models were created, printed, and tested for educational value in teaching complex cranial approaches. In this pilot study, assessments were made on the value of 3D printed models demonstrating the retrosigmoid and posterior petrosectomy approaches. Models were assessed and tested in a small cohort of neurosurgery resident subjects (n = 3) using a series of 10 radiographic and 2 printed case examples, with efficacy determined via agreement survey and approach selection accuracy. Results All subjects indicated agreement or strong agreement for all study endpoints that 3D printed models provided significant improvements in understanding of neuroanatomic relationships and principles of approach selection, as compared to 2D dissections or patient cross-sectional imaging alone. Models were not superior to in-person hands-on teaching. Mean approach selection accuracy was 90% (±13%) for 10 imaging-based cases, or 92% (±7%) overall. Trainees strongly agreed that approach decision-making was enhanced by adjunctive use of 3D models for both radiographic and printed cases. Conclusion 3D printed models incorporating skull base approaches and/or pathologies provide a compelling addition to the complex cranial education armamentarium. Based on our preliminary analysis, 3D printed models offer substantial potential for pedagogical value as dissection guides, adjuncts to preoperative study and case preparation, or tools for approach selection training and evaluation.

There are limited data regarding the surgical management of primary pulmonary artery sarcomas (PPAS) because of their rarity and complicated diagnostic history. The objective of this study was to analyze our institution’s long-term surgical management outcomes for PPAS in the absence of a care pathway. From May 1997 to June 2013, 8 patients (mean age 60.6 ± 11.8 years; range, 40-73 years; 5 women and 3 men) underwent surgical intervention for PPAS at our institution. The most common computed tomography finding was a luminal filling defect obstructing the pulmonary artery (PA), without evidence of extraluminal extension. Three patients underwent debulking/pulmonary endarterectomy alone and 5 patients underwent a more radical resection with PA patch angioplasty, PA resection and reconstruction, pulmonary valve replacement, and unilateral pneumonectomy. The mean postoperative survival in this series was 3.8 ± 3.6 years (range, 1-11.9 years), with 2 radical surgical resection patients alive at 4.9 and 11.9 years, respectively. For those patients with incomplete resection, 3-dimensional (3D) models were created to demonstrate the advantage of a preoperative guide for a more complete resection and what it would entail. Six patients had local recurrences with mean disease-free interval of 14 ± 10.9 months (range, 2 months-2.5 years), and 2 patients with re-resections had an overall postoperative survival of 2.8 and 11.9 years, respectively. In our small cohort of PPAS, patients treated with radical surgical resection had better survival. The small number of PPAS cases in this series makes proving this association unlikely but warrants consideration.

INTRODUCTION: The purpose of this study was to find out whether 3-dimensional (3D)–printed models improved the learners' ability to identify liver segments. METHODS: A total of 116 physicians from 3 disciplines were tested in a cross-over trial at baseline and after teaching with 3D models and 2-dimensional (2D) images. Adjusted multilevel-mixed models were used to compare scores at baseline and after 3D and 2D. RESULTS: Accuracy in identifying hepatic segments was higher with 3D first than 2D (77% vs 69%; P = 0.05) and not significantly improved by a combination of 3D and 2D. Increased confidence in segment identification was highest in trainees after 3D ( P = 0.04). DISCUSSION: 3D-printed models facilitate learning hepatic segmental anatomy.

Background In the discipline of rhinology and endoscopic skull base surgery (ESBS), 3-dimensional (3D) printing has found meaningful application in areas including preoperative surgical planning as well as in surgical education. However, its scope of use may be limited due to the perception among surgeons that there exists a prohibitively high initial investment in resources and time to acquire the requisite technical expertise. Nevertheless, given the ever decreasing cost of advancing technology coupled with the need to understand the complex spatial relationships of the paranasal sinuses and skull base, the use of 3D printing in rhinology and ESBS is poised to blossom. Objective Help the reader identify current or potential future uses of 3D printing technology relevant to their rhinologic clinical or educational practice. Methods A review of published literature relating to 3D printing in rhinology and ESBS was performed. Results Results were reviewed and organized into 5 overarching categories including an overview of the 3D printing process as well as applications of 3D printing including (1) surgical planning, (2) custom prosthetics and implants, (3) patient education, and (4) surgical teaching and assessment. Conclusion In the discipline of rhinology and ESBS, 3D printing finds use in the areas of presurgical planning, patient education, prosthesis creation, and trainee education. As this technology moves forward, these products will be more broadly available to providers in the clinical and educational setting. The possible applications are vast and have great potential to positively impact surgical training, patient satisfaction, and most importantly, patient outcomes.

ObjectiveTo examine the impact of 2‐dimensional (2D) illustrations and 3‐dimensonal (3D)–printed anatomic models of the frontal sinuses according to the International Frontal Sinus Anatomy Classification in the education of otolaryngology and radiology residents.Study DesignA crossover study design with half of the study participants randomized to the 2D illustration intervention first and the other half randomized to the 3D‐printed model first.SettingRegularly scheduled resident didactic lectures at a tertiary care center.Subjects and MethodsForty‐one otolaryngology and radiology residents were assessed with pre‐ and postintervention questionnaires that included subjective and objective methods of assessment.ResultsOverall, there was a statistically significant improvement in total number of answers correct and in confidence score between the pre‐ and postintervention assessments (P <. 0001). The primary outcome of order of intervention (ie, 2D → 3D vs 3D → 2D) did not result in statistically significant differences in postevaluation scores. In regard to the secondary outcome of learner preference for educational modality, radiology residents favored the 2D illustrations to understand anatomic relationships, while otolaryngology residents preferred the 3D model to be more helpful in surgical planning (P =. 0075).ConclusionThere is no difference between 2D‐illustrated and 3D‐printed International Frontal Sinus Anatomy Classification anatomic models in overall educational outcome, despite the preference of learners. Together, these models can be used as helpful tools in frontal sinus education for otolaryngology and radiology trainees.

Background The anatomy of the frontal sinus can pose a challenge for many neuroradiolgists and otolaryngologists, especially trainees. While much of resident education occurs in didactics, self-study or in the operating room, studies suggest that some trainees prefer hands-on learning. Three-dimensional (3D) printing technology provides users the opportunity to make customizable low-cost objects that provide tactile learning—a learning modality that may be preferable in education. Methods Three-dimensional printed models of frontal sinus anatomy based on selected patient computed tomography scans that represent various air cells according to the International Frontal Sinus Classification (IFAC) as different colored solid structures were printed using binder jetting. Results Seven unique de-identified patient scans were selected as the basis for the models so that all frontal cell types described in the IFAC scheme are represented between all 3D printed models. Conclusion This paper describes the technology and process necessary to create these models.

Metastatic pheochromocytoma and paraganglioma (PPGL) are incurable neuroendocrine tumors. The goals of treatment include palliating symptoms and reducing tumor burden. Little is known about the use of radiofrequency ablation (RFA), cryoablation (CRYO), and percutaneous ethanol injection (PEI) to treat metastatic PPGL. We performed a retrospective study of patients age 17 years and older with metastatic PPGL who were treated with ablative therapy at Mayo Clinic, USA, between June 14, 1999 and November 14, 2017. Our outcomes measures were radiographic response, procedure-related complications, and symptomatic improvement. Thirty-one patients with metastatic PPGL had 123 lesions treated during 42 RFA, 23 CRYO, and 4 PEI procedures. The median duration of follow-up was 60 months (range, 0–163 months) for non-deceased patients. Radiographic local control was achieved in 69/80 (86%) lesions. Improvement in metastasis-related pain or symptoms of catecholamine excess was achieved in 12/13 (92%) procedures. Thirty-three (67%) procedures had no known complications. Clavien-Dindo Grade I, II, IV, and V complications occurred after 7 (14%), 7 (14%), 1 (2%), and 1 (2%) of the procedures, respectively. In patients with metastatic PPGL, ablative therapy can effectively achieve local control and palliate symptoms.