Clinical studyA three-dimensional color-printed system allowing complete modeling of arteriovenous malformations for surgical simulations
Introduction
Arteriovenous malformations (AVMs) are complex conditions of the cerebral vasculature [9]. Brain AVM bleeding is a principal cause of death [3], [4]. AVMs often feature several feeding arteries and draining veins, and complex hemodynamic changes. Treatments include surgical resection, endovascular embolization, and radiation/combination therapy [5]. It is important to understand the overall structure of an AVM prior to surgery or endovascular treatment.
The use of three-dimensional (3D) printing to facilitate preoperative planning and surgical simulation is common in the fields of orthopedics, urology, and thoracic and plastic surgery [1], [7], [13], [15]. For cerebrovascular surgery, 3D printing has been used, but only rarely to simulate aneurysms and train surgeons [7], [11], [12], [15], [16]. We created colored, 3D-printed, comprehensive AVM models that included the feeding arteries, the nidus, the draining veins, the normal arteries, the skull, the adjacent arteries, and the skull base. Neurosurgeons were asked to rate such modeling in terms of its utility in preoperative planning.
Section snippets
Patients
We enrolled five AVM patients treated in our department between March 2016 and December 2017 (Table 1). Computed tomography angiography (CTA) and magnetic resonance venography (MRV) were performed before surgery.
Image post-processing
We used Mimics software (Materialise) to convert original CTA and MRV data into the Digital Image and Communication in Medicine (DICOM) format, applying appropriate vascular threshold values. A 3D-reconstruction technique was then used to build 3D models. Mimics considers multi-plane
Patient outcomes
We included five patients (one male and four females; mean age 38.8 ± 15.9 years [range, 24–61 years]) with cerebellar AVMs (n = 2), a ventricular AVM (n = 1), a corpus callosum AVM (n = 1), and a right temporal lobe AVM (n = 1) (Table 1). One patient underwent AVM surgery, and the others underwent endovascular embolization.
Evaluation
All patients underwent CTA, MRV, and DSA; 3D AVM models were printed using digital CTA and MRV data and used to simulate surgery or endovascular treatment. The AVM diameters, widths, and heights in the 3D models and MR images did not differ significantly (all p > 0.05; Table 2). The neurosurgeons and neurointerventionists completed questionnaires featuring seven questions (Table 3). Both 3D models and MR images were clinically useful.
Discussion
For over a decade, 3D printing has been used to create plates, artificial joints, and prostheses, as well as for anatomical modeling for both practical and educational applications [2], [8]. Customized cranioplasty implants enable perfect molding and are popular in the field of clinical neurosurgery [6]. In the field of cerebrovascular surgery, 3D printing has been used principally to create models of aneurysms. Brain AVMs are commonly encountered by neurosurgeons, and are complex, difficult to
Limitations
Dispersive AVMs cannot be 3D-printed; it is difficult to distinguish AVM brain tissue from dispersive vessels. Although AVMs usually feature multiple arterial feeds and draining veins, tiny arteries and veins cannot be imaged and thus cannot be printed. All current models are solid, hollows are not retained; the models cannot simulate intraoperative bleeding caused by rupture.
Conclusion
We used comprehensive 3D-printed AVM models to aid in preoperative planning and to train residents. The models improved surgeons’ skills and confidence.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
We thank all the workers (Man liu, Xiaomin Fan) in the Medprin Regenerative Medical Technologies CO.Ltd. for their excellent technical support. This work was supported by grants from; Guangdong province science and technology planning project (2018B090944002); Binhai New District Health Committee science and technology project (2019BWKY028).
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Brain arteriovenous malformations: A scoping review of experimental models
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