Vascular 3D Printing with a Novel Biological Tissue Mimicking Resin for Patient-Specific Procedure Simulations in Interventional Radiology: a Feasibility Study.

Three-dimensional (3D) printing of vascular structures is of special interest for procedure simulations in Interventional Radiology, but remains due to the complexity of the vascular system and the lack of biological tissue mimicking 3D printing materials a technical challenge. In this study, the technical feasibility, accuracy, and usability of a recently introduced silicone-like resin were evaluated for endovascular procedure simulations and technically compared to a commonly used standard clear resin. Fifty-four vascular models based on twenty-seven consecutive embolization cases were fabricated from preinterventional CT scans and each model was checked for printing success and accuracy by CT-scanning and digital comparison to its original CT data. Median deltas (Δ) of luminal diameters were 0.35 mm for clear and 0.32 mm for flexible resin (216 measurements in total) with no significant differences (p > 0.05). Printing success was 85.2% for standard clear and 81.5% for the novel flexible resin. In conclusion, vascular 3D printing with silicone-like flexible resin was technically feasible and highly accurate. This is the first and largest consecutive case series of 3D-printed embolizations with a novel biological tissue mimicking material and is a promising next step in patient-specific procedure simulations in Interventional Radiology.

3D Printed Surgical Simulation Models as educational tool by maxillofacial surgeons.

INTRODUCTION: The aim of this study was to evaluate whether inexpensive 3D models can be suitable to train surgical skills to dental students or oral and maxillofacial surgery residents. Furthermore, we wanted to know which of the most common filament materials, acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), can better simulate human bone according to surgeons' subjective perceptions. MATERIALS AND METHODS: Upper and lower jaw models were produced with common 3D desktop printers, ABS and PLA filament and silicon rubber for soft tissue simulation. Those models were given to 10 blinded, experienced maxillofacial surgeons to perform sinus lift and wisdom teeth extraction. Evaluation was made using a questionnaire. RESULTS: Because of slightly different density and filament prices, each silicon-covered model costs between 1.40-1.60 USD (ABS) and 1.80-2.00 USD (PLA) based on 2017 material costs. Ten experienced raters took part in the study. All raters deemed the models suitable for surgical education. No significant differences between ABS and PLA were found, with both having distinct advantages. CONCLUSION: The study demonstrated that 3D printing with inexpensive printing filaments is a promising method for training oral and maxillofacial surgery residents or dental students in selected surgical procedures. With a simple and cost-efficient manufacturing process, models of actual patient cases can be produced on a small scale, simulating many kinds of surgical procedures.

Can an entry-level 3D printer create high-quality anatomical models? Accuracy assessment of mandibular models printed by a desktop 3D printer and a professional device.

This study was performed to determine whether an in-house printed mandible model is sufficiently accurate for daily clinical practice. Ten example mandible models were produced with a desktop 3D printer (fused filament fabrication, FFF) and compared with 10 equivalent mandible models fabricated using a professional-grade 3D printer (selective laser sintering, SLS). To determine the precision of the printed models, each model was scanned with an optical scanner. Subsequently, every model was compared to its original standard tessellation language (STL) file and to its corresponding analogue. Mean±standard deviation and median (interquartile range) differences were calculated. Overall these were -0.019±0.219mm and -0.007 (-0.129 to 0.107) mm for all 10 pairs. Furthermore, correlation of all printed models to their original STL files showed a high level of accuracy. Comparison of the SLS models with their STL files revealed a mean difference of -0.036±0.114mm and median difference of -0.028 (-0.093 to 0.030) mm. Comparison of the FFF models with their STL files yielded a mean difference of -0.055±0.227mm and median difference of -0.022 (-0.153 to 0.065) mm. The study findings confirm that in-house 3D printed mandible models are economically favourable as well as suitable substitutes for professional-grade models, in particular considering the geometric aspects.

[Surgical treatment of esophagotracheal and esophagobronchial fistulas]. / Chirurgische Versorgung ösophagotrachealer und -bronchialer Fisteln.

BACKGROUND: Esophagotracheal and esophagobronchial fistulas are pathological communications between the airway system and the digestive tract, which often lead to major pulmonary complications with a high mortality. Endoscopic treatment is the primary therapeutic approach; however, in cases of failure early surgical treatment is obligatory. METHODS: This article describes the clinical course of patients with esophagotracheal and esophagobronchial fistulas treated in this hospital over a period of 10 years. Patients were retrospectively analyzed with respect to the etiology of fistulas, management, in particular to the operative procedures, complications and outcome. RESULTS: Between 2009 and 2019, a total of 15 patients with esophagotracheal and esophagobronchial fistula were treated in this hospital. Of these 12 underwent an endoscopic intervention, of which 5 were successful. In total, eight patients needed surgical intervention, six of the eight surgically treated patients recovered fully, one had a recurrent fistula, which was successfully treated by subsequent endoscopy after surgery and one patient died. DISCUSSION: Management of esophagotracheal and esophagobronchial fistulas is challenging. This retrospective analysis reflects the published data with a success rate of endoscopic treatment in approximately 50%. Surgical intervention should be carried out after unsuccessful endoscopic treatment or if endoscopic treatment is primarily not feasible. Direct closure with resorbable sutures or reconstruction with alloplastic or allogeneic material should be preferred. For larger defects or high proximal esophagotracheal fistulas local transposition of muscular flaps or free muscular flaps play a major role. During operative closure of high intrathoracic or cervical fistulas, intraoperative neuromonitoring can be useful to prevent nerve damage.