The meta-analysis showed that LLR is beneficial in terms of overall morbidity and non-procedure-specific complications. That being said, these results are based on non-randomized trials. For these reasons, we are calling for randomization in upcoming studies. Systematic review registration: PROSPERO registration number CRD42018084576.

PurposeAlthough high costs are often cited as the main limitation of 3D printing (3DP) in the medical field, current lack of clinical evidence is asserting itself as an impost as the field begins to mature. The aim is to review clinical trials in the field of 3DP, an area of research which has grown dramatically in recent years.MethodsWe surveyed clinical trials registered in 15 primary registries worldwide, including ClinicalTrials.gov. All trials which utilized 3DP in a clinical setting were included in this review. Our search was performed on December 15, 2017. Data regarding the purpose of the study, inclusion criteria, number of patients enrolled, primary outcomes, centers, start and estimated completion dates were extracted.ResultsA total of 92 clinical trials with 252 patients matched the criteria and were included in the study. A total of 42 (45.65%) studies cited China as their location. Only 10 trials were multicenter and 2 were registered as international. The discipline that most commonly utilized 3DP was Orthopedic Surgery, with 25 (27.17%) registered trials. At the time of data extraction, 17 (18.48%) clinical trials were complete.ConclusionsAfter several years of case reports, feasibility studies and technical reports in the field, larger-scale studies are beginning to emerge. There are almost no international register entries. Although there are new emerging areas of study in disciplines that may benefit from 3DP, it is likely to remain limited to very specific applications.Electronic supplementary materialThe online version of this article (10.1007/s11548-018-1793-8) contains supplementary material, which is available to authorized users.

IntroductionLeft atrial appendage occlusion procedure (LAAO) became an alternative method for stroke prevention in atrial fibrillation (AF) patients with contraindication or intolerance for oral anticoagulation therapy. However, LAA anatomy is complex with several different types of LAA morphology. Therefore matching the correct size of a delivery device to LAA morphology is difficult. In such circumstances, the 3D-printed model of LAA closure may be useful for preoperative planning which increases the efficacy of LAAO procedure.Material and methodsWe report as a first 2 cases of LAA occlusion procedure using 2 different systems: thoracoscopic AtriClip and the LARIAT device in which a 3D printed LAA model was used in preoperative planning.ResultsIn the first patient, preoperative measurements of 3D LAA model were performed using a dedicated selection guide for AtriClip device were comparable with the intraoperative examination. Left atrial appendage was closed epicardial using 40 mm size AtriClip. In second patients, LAA closure was performed completely percutaneously using LARIAT device. For better visualization of LAA shape on fluoroscopy and TEE examination, intraoperatively sterilized 3D LAA model was used during the procedure. In both cases, intraoperative TEE examination confirmed complete LAA closure with no leak.ConclusionsLeft atrial appendage 3D model is a useful tool in preoperative planning of a left atrial appendage occlusion using epicardial approaches with thoracoscopic or percutaneous access using LARIAT device. The quality of low-cost 3D printed LAA model is sufficient in planning minimally invasive procedure.

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