Cerebrovascular stereolithographic biomodeling for aneurysm surgery

Abstract

Stereolithographic (SL) biomodeling is a new technology that allows three-dimensional (3D) imaging data to be used in the manufacture of accurate solid plastic replicas of anatomical structures. The authors describe their experience with a patient series in which this relatively new visualization method was used in surgery for cerebral aneurysms. Using the rapid prototyping technology of stereolithography, 13 solid anatomical biomodels of cerebral aneurysms with parent and surrounding vessels were manufactured based on 3D computerized tomography scans (three cases) or 3D rotational angiography (10 cases). The biomodels were used for diagnosis, operative planning, surgical simulation, instruction for less experienced neurosurgeons, and patient education. The correspondence between the biomodel and the intraoperative findings was verified in every case by comparison with the intraoperative video. The utility of the biomodels was judged by three experienced and two less experienced neurosurgeons specializing in microsurgery. A prospective comparison of SL biomodels with intraoperative findings proved that the biomodels replicated the anatomical structures precisely. Even the first models, which were rather rough, corresponded to the intraoperative findings. Advances in imaging resolution and postprocessing methods helped overcome the initial limitations of the image threshold. The major advantage of this technology is that the surgeon can closely study complex cerebrovascular anatomy from any perspective by using a haptic, "real reality" biomodel, which can be held, allowing simulation of intraoperative situations and anticipation of surgical challenges. One drawback of SL biomodeling is the time it takes for the model to be manufactured and delivered. Another is that the synthetic resin of the biomodel is too rigid to use in dissecting exercises. Further development and refinement of the method is necessary before the model can demonstrate a mural thrombus or calcification or the relationship of the aneurysm to nonvascular structures. This series of 3D SL biomodels demonstrates the feasibility and clinical utility of this new visualization medium for cerebrovascular surgery. This medium, which elicits the intuitive imagination of the surgeon, can be effectively added to conventional imaging techniques. Overcoming the present limitations posed by material properties, visualization of intramural particularities, and representation of the relationship of the lesion to parenchymal and skeletal structures are the focus in an ongoing trial.

Rapid prototyping of three-dimensional biomodels as an adjuvant in the surgical planning for intracranial aneurysms

“…Moreover, prototypes do not show the presence of intra-arterial thrombus or calcification, which has previously been described 14,16 . However, according to Kimura et al …”

“…It is commonly difficult to predict the size, quantity and angles of the clips to be used for each aneurysm. Thus, being identical to the actual structures, biomodels can facilitate the prediction of surgical techniques and approaches during the preoperative period 14,15 .…”

“…At the beginning, Wurm et al 14 believed that the vessel wall, the geometry of the neck, the configuration and direction of the aneurysm and evidence of small perforating arteries would be the most important characteristics targeted by the surgeon. After application of a questionnaire to five surgeons, this hypothesis was confirmed.…”

“…As a matter of fact, biomodels can facilitate the explanation of the case and surgical risk to the patients and their relatives 14,15 . Studies have reported that the existence of a physical prototype, in fact, assisted in obtaining informed consent of the patients, improved understanding the disease and the surgical procedure that would be performed 14,16 . Finally, it is important to emphasize that an actual physical model of the 3D surgical anatomy preoperatively provides great confidence to the surgeon, and consequently to the patient, and may even reduce the surgical time and risk.…”

Advanced 3-D Biomodelling Technology for Complex Mandibular Reconstruction

“…Application of biomodeling technology has also been reported in neurosurgery (D'Urso & Redmond, 1999b, 1999c& 2000bSinn et al, 2006;Westendorf et al, 2007;Staffa et al, 2007;Wurm et al, 2004), orthopedic surgery (Fukui et al, 2003;Brown et al, 2002& Gutierres et al, 2007, cardiology and cardio-thoracic surgery (Sodian et al, 2002& Greil et al, 2007, vascular surgery (Lermusiaux et al, 2001), facial aging (Pessa, 2000(Pessa, & 2001, alloplasty (Coward et al, 1999), forensic medicine (Dolz et al, 2000& Vanezi et al, 2000 and fetal medicine (D'Urso & Thompson, 1998).…”