An approach to EVAR simulation using patient specific modeling

3D printing in the planning and teaching of endovascular procedures

BACKGROUND

The introduction of 3D printing in the medical field led to new possibilities in the planning of complex procedures, as well as new ways of training junior physicians. Especially in the field of vascular interventions, 3D printing has a wide range of applications.

METHODOLOGICAL INNOVATIONS

3D-printed models of aortic aneurysms can be used for procedural training of endovascular aortic repair (EVAR), which can help boost the physician's confidence in the procedure, leading to a better outcome for the patient. Furthermore, it allows for a better understanding of complex anatomies and pathologies. In addition to teaching applications, the field of pre-interventional planning benefits greatly from the addition of 3D printing. Especially in the preparation for a complex endovascular aortic repair, prior orientation and test implantation of the stent grafts can further improve outcomes and reduce complications. For both teaching and planning applications, high-quality imaging datasets are required that can be transferred into a digital 3D model and subsequently printed in 3D. Thick slice thickness or suboptimal contrast agent phase can reduce the overall detail of the digital model, possibly concealing crucial anatomical details.

CONCLUSION

Based on the digital 3D model created for 3D printing, another new visualization technique might see future applications in the field of vascular interventions: virtual reality (VR). It enables the physician to quickly visualize a digital 3D model of the patient's anatomy in order to assess possible complications during endovascular repair. Due to the short transfer time from the radiological dataset into the VR, this technique might see use in emergency situations, where there is no time to wait for a printed model.

Advanced Manufacturing in the Fabrication of a Lifelike Brain Glioblastoma Simulator for the Training of Neurosurgeons

Neurosurgeons require considerable expertise and practical experience to deal with the critical situations commonly encountered in complex surgical operations such as cerebral cancer; however, trainees in neurosurgery seldom have the opportunity to develop these skills in the operating room. Physical simulators can give trainees the experience they require. In this study, we adopted advanced molding and replication techniques in the fabrication of a physical simulator for use in practicing the removal of cerebral tumors. Our combination of additive manufacturing and molding technology with elastic material casting made it possible to create a simulator that realistically mimics the skull, brain stem, soft brain lobes, and cerebral cancer with cerebral tumors located precisely where they are likely to appear. Multiple and systematic experiments were conducted to prove that the elastic material used herein was appropriated for building professional medical physical simulator. One neurosurgical trainee reported that under the guidance of a senior neurosurgeon, the physical simulator helped to elucidate the overall process of cerebral cancer removal and provided a realistic impression of the tactile feelings involved in craniotomy. The trainee also learned how to make decisions when facing the infiltration of a cerebral tumor into normal brain lobes. Our results demonstrate the efficacy of the proposed physical simulator in preparing trainees for the rigors involved in performing highly delicate surgical operations.

Engineering Additive Manufacturing and Molding Techniques to Create Lifelike Willis' Circle Simulators with Aneurysms for Training Neurosurgeons

Neurosurgeons require considerable expertise and practical experience in dealing with the critical situations commonly encountered during difficult surgeries; however, neurosurgical trainees seldom have the opportunity to develop these skills in the operating room. Therefore, physical simulators are used to give trainees the experience they require. In this study, we created a physical simulator to assist in training neurosurgeons in aneurysm clipping and the handling of emergency situations during surgery. Our combination of additive manufacturing with molding technology, elastic material casting, and ultrasonication-assisted dissolution made it possible to create a simulator that realistically mimics the brain stem, soft brain lobes, cerebral arteries, and a hollow transparent Circle of Willis, in which the thickness of vascular walls can be controlled and aneurysms can be fabricated in locations where they are likely to appear. The proposed fabrication process also made it possible to limit the error in overall vascular wall thickness to just 2–5%, while achieving a Young’s Modulus closely matching the characteristics of blood vessels (~5%). One neurosurgical trainee reported that the physical simulator helped to elucidate the overall process of aneurysm clipping and provided a realistic impression of the tactile feelings involved in this delicate operation. The trainee also experienced shock and dismay at the appearance of leakage, which could not immediately be arrested using the clip. Overall, these results demonstrate the efficacy of the proposed physical simulator in preparing trainees for the rigors involved in performing highly delicate neurological surgical operations.

Operators believe patient-specific rehearsal improve individual and team performance

INTRODUCTION

Rehearsing endovascular aortic aneurysm repair on patient-specific data is recent within virtual reality simulation and opens up new possibilities for operators to prepare for complex procedures. This study evaluated the feasibility of patient-specific rehearsal (PsR) and assessed operators' appraisal of the VIST-LAB simulator from Mentice.

MATERIAL AND METHODS

CT-data was segmented and uploaded to the simulator, and simulated for 30 elective EVAR patients. Operators were asked how they perceived the PsR on a Likert scale after the PsR (once) and after the following procedure (each time).

RESULTS

Patients were simulated and operated by 14 operators, always in pairs of one vascular surgeon and one interventional radiologist. The operators estimated that PsR improved individual and team performance (median 4), and recommended the use of PsR in general (median 4) and for difficult cases (median 5). The simulator realism got moderate scores (median 2-3). Inexperienced operators seemed to appreciate the PsR the most.

CONCLUSIONS

PsR was feasible and was evaluated by operators to improve individual and team performance. Inexperienced users were more positive towards PsR than experienced users. PsR realism and the ease of importing patient-specific data can still be improved, and further studies to quantify and precisely identify benefits are needed.

Influence of patient-specific rehearsal on operative metrics and technical success for endovascular aneurysm repair

INTRODUCTION

Patient-specific rehearsal (PsR) is a recent technology within virtual reality (VR) simulation that lets the operators train on patient-specific data in a simulated environment prior to the procedure. Endovascular aneurysm repair (EVAR) is a complex procedure where operative metrics and technical success might improve after PsR.

MATERIAL AND METHODS

We compared technical success and operative metrics (endovascular procedure time, contralateral gate cannulation time, fluoroscopy time, total radiation dose, number of angiograms and contrast medium use) between 30 patients, where the operators performed PsR (the PsR group), and 30 patients without PsR (the control group).

RESULTS

The endovascular procedure time was significantly shorter in the PsR group than in the control group (median 44 versus 55 min, p = .017). The other operative metrics were similar. Technical success rates were higher in the PsR group, 96.7% primary and assisted primary outcome versus 90.0% in the control group. The differences were not significant (p = .076).

CONCLUSIONS

PsR before EVAR reduced endovascular procedure time, and our results indicate that it might improve technical success, but further studies are needed to confirm those results.

Simulation of Endovascular Aortic Repair Using 3D Printed Abdominal Aortic Aneurysm Model and Fluid Pump

BACKGROUND

Abdominal aortic aneurysm (AAA) models can be manufactured with 3D printing technology. This study describes detailed methodology and validation of endovascular aortic repair (EVAR) simulation using 3D printed AAA model connected to hemodynamic pump.

METHOD

The AAA model was printed with Objet500 Connex3 (Stratasys, Eden Prairie, MN) and connected to BDC PD-0500 fluid pump (BDC Laboratories, Wheat Ridge, CO). EVAR procedure metrics were benchmarked in two expert implanters and compared to 20 vascular surgical trainees with different levels of EVAR experience (< 20 or ≥ 20 cases). All simulations were performed using commercially available stent grafts, guidewires, catheters, fluoroscopic guidance and digital subtraction angiography. Studied outcomes included ability to complete the procedure independently, time to deploy aortic component, ability to cannulate contralateral gate and complete the repair, and total fluoroscopy and procedure times.

RESULTS

A total of 22 EVAR simulation procedures were performed with mean procedure time of 37 ± 12 min. Experienced trainees had significantly lower total procedural time (32 ± 9 vs. 44 ± 6 min, P = 0.003) and fluoroscopic time (13 ± 5 vs. 23 ± 8 min, P = 0.005). All experienced trainees completed the procedure independently in < 45 min, compared to six (46%) of those with less EVAR experience (P = 0.016). Among less experienced trainees, only two (15%) completed the entire procedure independently (P < 0.001). Benchmark implanters performed significantly better than both trainee groups in nearly all EVAR metrics.

CONCLUSION

EVAR simulation was feasible and simulated all procedural steps with high fidelity. This model may be applicable for assessment of technical competencies and standard endovascular skill acquisition within vascular surgery training curricula.

Artificial vascular models for endovascular training (3D printing)

The endovascular technique has led to a revolution in the care of patients with vascular disease; however, acquiring and maintaining proficiency over a broad spectrum of procedures is challenging. Three-dimensional (3D) printing technology allows the production of models that can be used for endovascular training. This article aims to explain the process and technologies available to produce vascular models for endovascular training, using 3D printing technology. The data are based on the group experience and a review of the literature. Different 3D printing methods are compared, describing their advantages, disadvantages and potential roles in surgical training. The process of 3D printing a vascular model based on an imaging examination consists of the following steps: image acquisition, image post-processing, 3D printing and printed model post-processing. The entire process can take a week. Prospective studies have shown that 3D printing can improve surgical planning, especially in complex endovascular procedures, and allows the production of efficient simulators for endovascular training, improving residents’ surgical performance and self-confidence.

REHEARSAL Using Patient-Specific Simulation to Improve Endovascular Efficiency

OBJECTIVE

To determine whether rehearsal using patient-specific information loaded onto an endovascular simulator prior to carotid stenting improves procedural efficiency and outcomes.

METHODS

Patients scheduled for carotid artery stenting who had adequate preoperative computed tomography (CT) imaging were considered for enrollment. After obtaining informed consent, patients were randomized to control versus rehearsal groups. Those in the rehearsal group had their CT scans loaded into an endovascular simulator (Angio Mentor) followed by case rehearsal by the attending on the simulator within 24 hours prior to the procedure; control patients underwent routine carotid stenting without rehearsal. Contrast usage, fluoroscopy time, and timing of procedural steps were recorded by a blinded observer during the actual case to determine benefit.

RESULTS

Fifteen patients were enrolled, with 6 patients randomized to the rehearsal group and 9 to the control. All measures showed improvement in the rehearsal group: Mean contrast volume (59.2 vs 76.9 mL), fluoroscopy time (11.4 vs 19.4 minutes), overall operative time (31.9 vs 42.5 minutes), time to common carotid sheath placement (17.0 vs 23.3 minutes), and total carotid sheath dwell time (14.9 vs 19.2 minutes) were all lower (more favorable) in the rehearsal group. The study was terminated early due to the lack of simulator access, and all P values were thus greater than .05 due to the lack of power. No strokes or other adverse events occurred in either group.

CONCLUSION

Case-specific simulator rehearsal using patient-specific imaging prior to carotid stenting is associated with numerically less contrast usage, operative time, and radiation exposure, although this study was underpowered.

A simulator for training in endovascular aneurysm repair: The use of three dimensional printers

OBJECTIVES

To develop an endovascular aneurysm repair (EVAR) simulation system using three dimensional (3D) printed aneurysms, and to evaluate the impact of patient specific training prior to EVAR on the surgical performance of vascular surgery residents in a university hospital in Brazil.

METHODS

This was a prospective, controlled, single centre study. During 2015, the aneurysms of patients undergoing elective EVAR at São Paulo University Medical School were 3D printed and used in training sessions with vascular surgery residents. The 3D printers Stratasys-Connex 350, Formlabs-Form1+, and Makerbot were tested. Ten residents were enrolled in the control group (five residents and 30 patients in 2014) or the training group (five residents and 25 patients in 2015). The control group performed the surgery under the supervision of a senior vascular surgeon (routine procedure, without simulator training). The training group practised the surgery in a patient specific simulator prior to the routine procedure. Objective parameters were analysed, and a subjective questionnaire addressing training utility and realism was answered.

RESULTS

Patient specific training reduced fluoroscopy time by 30% (mean 48 min, 95% confidence interval [CI] 40-58 vs. 33 min, 95% CI 26-42 [p < .01]), total procedure time by 29% (mean 292 min [95% CI 235-336] vs. 207 [95% CI 173-247]; p < .01), and volume of contrast used by 25% (mean 87 mL [95% CI 73-103] vs. 65 mL [95% CI 52-81]; p = .02). The residents considered the training useful and realistic, and reported that it increased their self confidence. The 3D printers Form1+ (using flexible resin) and Makerbot (using silicone) provided the best performance based on simulator quality and cost.

CONCLUSION

An EVAR simulation system using 3D printed aneurysms was feasible. The best results were obtained with the 3D printers Form1+ (using flexible resin) and Makerbot (using silicone). Patient specific training prior to EVAR at a university hospital in Brazil improved residents' surgical performance (based on fluoroscopy time, surgery time, and volume of contrast used) and increased their self confidence.

Patient-specific Rehearsal Before EVAR: Influence on Technical and Nontechnical Operative Performance. A Randomized Controlled Trial

OBJECTIVE

To assess the effect of patient-specific virtual reality rehearsal (PsR) before endovascular infrarenal aneurysm repair (EVAR) on technical performance and procedural errors.

BACKGROUND

Endovascular procedures, including EVAR, are executed in a complex multidisciplinary environment, often treating high-risk patients. Consequently, this may lead to patient harm and procedural inefficiency. PsR enables the endovascular team to evaluate and practice the case in a virtual environment before treating the real patient.

METHODS

A multicenter, prospective, randomized controlled trial recruited 100 patients with a nonruptured infrarenal aortic or iliac aneurysm between September 2012 and June 2014. Cases were randomized to preoperative PsR or standard care (no PsR). Primary outcome measures were errors during the real procedure and technical operative metrics (total endovascular and fluoroscopy time, contrast volume, number of angiograms, and radiation dose).

RESULTS

There was a 26% [95% confidence interval (CI) 9%-40%, P = 0.004) reduction in minor errors, a 76% (95% CI 30%-92%, P = 0.009) reduction in major errors, and a 27% (95% CI 8.2%-42%, P = 0.007) reduction in errors causing procedural delay in the PsR group. The number of angiograms performed to visualize proximal and distal landing zones was 23% (95% CI 8%-36%, P = 0.005) and 21% (95% CI 7%-32%, P = 0.004) lower in the PsR group.

CONCLUSIONS

PsR before EVAR can be used in different hospital settings by teams with various EVAR experience. It reduces perioperative errors and the number of angiograms required to deploy the stent graft, thereby reducing delays. Ultimately, it may improve patient safety and procedural efficiency.

Augmented-reality integrated robotics in neurosurgery: are we there yet?

Surgical robots have captured the interest—if not the widespread acceptance—of spinal neurosurgeons. But successful innovation, scientific or commercial, requires the majority to adopt a new practice. “Faster, better, cheaper” products should in theory conquer the market, but often fail. The psychology of change is complex, and the “follow the leader” mentality, common in the field today, lends little trust to the process of disseminating new technology. Beyond product quality, timing has proven to be a key factor in the inception, design, and execution of new technologies. Although the first robotic surgery was performed in 1985, scant progress was seen until the era of minimally invasive surgery. This movement increased neurosurgeons’ dependence on navigation and fluoroscopy, intensifying the drive for enhanced precision. Outside the field of medicine, various technology companies have made great progress in popularizing co-robots (“cobots”), augmented reality, and processor chips. This has helped to ease practicing surgeons into familiarity with and acceptance of these technologies. The adoption among neurosurgeons in training is a “follow the leader” phenomenon, wherein new surgeons tend to adopt the technology used during residency. In neurosurgery today, robots are limited to computers functioning between the surgeon and patient. Their functions are confined to establishing a trajectory for navigation, with task execution solely in the surgeon’s hands. In this review, the authors discuss significant untapped technologies waiting to be used for more meaningful applications. They explore the history and current manifestations of various modern technologies, and project what innovations may lie ahead.

A Multicentre Trial of Patient specific Rehearsal Prior to EVAR: Impact on Procedural Planning and Team Performance

OBJECTIVE

Patient specific rehearsal (PsR) prior to endovascular aneurysm repair (EVAR) enables the endovascular team to practice and evaluate the procedure prior to treating the real patient. This multicentre trial aimed to evaluate the utility of PsR prior to EVAR as a pre-operative planning and briefing tool.

MATERIAL AND METHODS

Patients with an aneurysm suitable for EVAR were randomised to pre-operative or post-operative PsR. Before and after the PsR, the lead implanter completed a questionnaire to identify any deviation from the initial treatment plan. All team members completed a questionnaire evaluating realism, technical issues, and human factor aspects pertinent to PsR. Technical and human factor skills, and technical and clinical success rates were compared between the randomised groups.

RESULTS

100 patients were enrolled between September 2012 and June 2014. The plan to visualise proximal and distal landing zones was adapted in 27/50 (54%) and 38/50 (76%) cases, respectively. The choice of the main body, contralateral limb, or iliac extensions was adjusted in 8/50 (16%), 17/50 (34%), and 14/50 (28%) cases, respectively. At least one of the abovementioned parameters was changed in 44/50 (88%) cases. For 100 EVAR cases, 199 subjective questionnaires post-PsR were completed. PsR was considered to be useful for selecting the optimal C-arm angulation (median 4, IQR 4-5) and was recognised as a helpful tool for team preparation (median 4, IQR 4-4), to improve communication (median 4, IQR 3-4), and encourage confidence (median 4, IQR 3-4). Technical and human factor skills and technical and initial clinical success rates were similar between the randomisation groups.

CONCLUSION

PsR prior to EVAR has a significant impact on the treatment plan and may be useful as a pre-operative planning and briefing tool. Subjective ratings indicate that this technology may facilitate planning of optimal C-arm angulation and improve non-technical skills.

TRIAL REGISTRATION

URL://www.clinicaltrials.gov. Unique identifier: NCT01632631.

Getting back together after a break-up: Relationship advice for anatomists and surgeons

The "surgeon-anatomist" was originally a single individual who self-pursued knowledge and understanding of anatomy as the foundation for successful surgical outcomes. However, recent advances in medical education have ironically led to the separation of anatomy and surgery. This physical and emotional "divorce" of anatomists and surgeons into separate individuals has created several critical educational issues for medical and surgical educators including a general lack of anatomical knowledge in medical students and misalignment of graduate medical education procedural specialty training with the Accreditation Council of Graduate Medical Education Core Competencies and now the Next Accreditation System. There are numerous opportunities for anatomists and surgeons to work together to improve educational instruction of established difficult anatomical regions, procedural training, or even develop new techniques and procedures. Similarly, anatomists with specialized training in medical education would be invaluable partners to ensure that procedural assessments align with instructional technologies for truly longitudinal curricula that starts at the medical student level, but stops at the patient outcomes of attending surgeons. This mutually beneficial relationship would be similar to multidisciplinary care teams and current surgeon and PhD/EdD partnerships. The restoration of the relationship between anatomists and surgeons would be invaluable to surgical education and remains an exciting research opportunity.