Impact of a Vascular Neurosurgery Simulation-Based Course on Cognitive Knowledge and Technical Skills in European Neurosurgical Trainees

Simulation for skills training in neurosurgery: a systematic review, meta-analysis, and analysis of progressive scholarly acceptance

At a time of significant global unrest and uncertainty surrounding how the delivery of clinical training will unfold over the coming years, we offer a systematic review, meta-analysis, and bibliometric analysis of global studies showing the crucial role simulation will play in training. Our aim was to determine the types of simulators in use, their effectiveness in improving clinical skills, and whether we have reached a point of global acceptance. A PRISMA-guided global systematic review of the neurosurgical simulators available, a meta-analysis of their effectiveness, and an extended analysis of their progressive scholarly acceptance on studies meeting our inclusion criteria of simulation in neurosurgical education were performed. Improvement in procedural knowledge and technical skills was evaluated. Of the identified 7405 studies, 56 studies met the inclusion criteria, collectively reporting 50 simulator types ranging from cadaveric, low-fidelity, and part-task to virtual reality (VR) simulators. In all, 32 studies were included in the meta-analysis, including 7 randomised controlled trials. A random effects, ratio of means effects measure quantified statistically significant improvement in procedural knowledge by 50.2% (ES 0.502; CI 0.355; 0.649, p < 0.001), technical skill including accuracy by 32.5% (ES 0.325; CI - 0.482; - 0.167, p < 0.001), and speed by 25% (ES - 0.25, CI - 0.399; - 0.107, p < 0.001). The initial number of VR studies (n = 91) was approximately double the number of refining studies (n = 45) indicating it is yet to reach progressive scholarly acceptance. There is strong evidence for a beneficial impact of adopting simulation in the improvement of procedural knowledge and technical skill. We show a growing trend towards the adoption of neurosurgical simulators, although we have not fully gained progressive scholarly acceptance for VR-based simulation technologies in neurosurgical education.

Three-Dimensional Modeling in Training, Simulation, and Surgical Planning in Open Vascular and Endovascular Neurosurgery: A Systematic Review of the Literature

BACKGROUND

The expanding use of three-dimensional (3D) printing in open vascular and endovascular neurosurgery presents a promising new tool in resident learning as well as operative planning. Recent studies have investigated the accuracy, efficacy, and practicality of 3D-printed models of patient-specific disease.

OBJECTIVE

To review the literature exploring 3D modeling in neurovascular and endovascular surgery for training, simulation, and surgical preparation.

METHODS

A systematic search of the PubMed database was conducted using keywords relating to 3D printing and neurovascular or endovascular surgery. Articles were manually screened to include those that focused on resident training, surgical simulation, or preoperative planning. Information on fabrication method, materials, cost, and validation measures was collected.

RESULTS

A total of 27 articles were identified that met inclusion criteria. Twenty-one studies used 3D printing to produce aneurysm models, 5 produced arteriovenous malformation models, and 1 produced aneurysm and arteriovenous malformation models. Stereolithography was the most common fabrication method used, with acrylonitrile butadiene styrene and VeroClearTangoPlus (Stratasys) being the most frequently used materials. The mean manufacturing cost per model was U.S. $624.83. Outcomes included model measurement accuracy, concordance of intraoperative devices with those selected preoperatively, and qualitative feedback.

CONCLUSIONS

Models generated by 3D printing are anatomically accurate and aid in resident learning as well as operative planning in open vascular and endovascular neurosurgery. As advancements in printing methods are made and manufacturing costs decrease, this tool may supplement training on a wider scale in a field in which direct exposure to cases is limited.

Indocyanine green videoangiography for recipient vessel stratification in superficial temporal artery-middle cerebral artery bypass surgery

OBJECTIVE

In superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery, recipient vessel properties are likely one of the main reasons for bypass failure. In daily practice, most surgeons select the recipient with the largest diameter. However, selection of the ideal recipient remains debatable because there are no objective selection criteria if multiple potential recipients exist. Here, the authors assessed the benefit of using indocyanine green videoangiography (ICG-VA) to optimize recipient vessel selection in patients undergoing STA-MCA bypass surgery for hemodynamic compromise.

METHODS

All patients who had undergone STA-MCA bypass procedures with pre- and postanastomosis ICG-VA between 2010 and 2019 were eligible for inclusion in this study. The primary bypass surgeon was blinded to the preanastomosis ICG-VA. Preanastomosis white-light and ICG-VA images were compared to determine the identifiability of potential recipient vessels and pathological flow patterns. After completion of the anastomosis, a second (postanastomosis) ICG-VA image was used to analyze the flow increase within the chosen recipient based on the vessel diameter, initial recipient blood flow, initial sequence of appearance on ICG-VA, initial blood flow direction within the recipient, and orientation of the bypass graft. ICG-VA, FLOW 800, and intraoperative white-light images, as well as demographic, clinical, and radiographic patient data, were retrospectively analyzed by a clinician who was not directly involved in the patients' care.

RESULTS

Sixty patients underwent 65 STA-MCA bypass procedures with pre- and postanastomosis ICG-VA. The ICG-VA permitted identification of a significantly higher number of potential recipient vessels (median 4, range 1-9) than the white-light images (median 2, range 1-5; p < 0.001), with detection of pathological flow patterns in 20% of all procedures. No association was found between the diameter and blood flow within potential recipients (Spearman r = 0.07, p = 0.69). After bypass grafting, the highest flow increase was noted in recipients with an initially low flow (p < 0.01), a late appearance (p < 0.01), and an initially retrograde flow direction (p = 0.02). Interestingly, flow increase was not significantly influenced by the recipient diameter (p = 0.09) or graft orientation (p = 0.44).

CONCLUSIONS

ICG-VA facilitates identification of potential recipient vessels and detection of pathological flow patterns. Recipients with an initially low flow, a late appearance, and a retrograde flow seem to bear the highest potential for flow increase, possibly due to a higher hemodynamic need for revascularization.

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.

Procedures performed during neurosurgery residency in Europe

Background

In a previous article (10.1007/s00701-019-03888-3), preliminary results of a survey, aiming to shed light on the number of surgical procedures performed and assisted during neurosurgery residency in Europe were reported. We here present the final results and extend the analyses.

Methods

Board-certified neurosurgeons of European Association of Neurosurgical Societies (EANS) member countries were asked to review their residency case logs and participate in a 31-question electronic survey (SurveyMonkey Inc., San Mateo, CA). The responses received between April 25, 2018, and April 25, 2020, were considered. We excluded responses that were incomplete, from non-EANS member countries, or from respondents that have not yet completed their residency.

Results

Of 430 responses, 168 were considered for analysis after checking in- and exclusion criteria. Survey responders had a mean age of 42.7 ± 8.8 years, and 88.8% were male. Responses mainly came from surgeons employed at university/teaching hospitals (85.1%) in Germany (22.0%), France (12.5%), the United Kingdom (UK; 8.3%), Switzerland (7.7%), and Greece (7.1%). Most responders graduated in the years between 2011 and 2019 (57.7%). Thirty-eight responders (22.6%) graduated before and 130 responders (77.4%) after the European WTD 2003/88/EC came into effect. The mean number of surgical procedures performed independently, supervised or assisted throughout residency was 540 (95% CI 424–657), 482 (95% CI 398–568), and 579 (95% CI 441–717), respectively. Detailed numbers for cranial, spinal, adult, and pediatric subgroups are presented in the article. There was an annual decrease of about 33 cases in total caseload between 1976 and 2019 (coeff. − 33, 95% CI − 62 to − 4, p = 0.025). Variables associated with lesser total caseload during residency were training abroad (1210 vs. 1747, p = 0.083) and female sex by trend (947 vs. 1671, p = 0.111), whereas case numbers were comparable across the EANS countries (p = 0.443).

Conclusion

The final results of this survey largely confirm the previously reported numbers. They provide an opportunity for current trainees to compare their own case logs with. Again, we confirm a significant decline in surgical exposure during training between 1976 and 2019. In addition, the current analysis reveals that female sex and training abroad may be variables associated with lesser case numbers during residency.

Electronic supplementary material

The online version of this article (10.1007/s00701-020-04513-4) contains supplementary material, which is available to authorized users.

Assessment of the Interrater Reliability of the Congress of Neurological Surgeons Microanastomosis Assessment Scale

BACKGROUND

The potential for simulation-based learning in neurosurgical training has led the Congress of Neurosurgical Surgeons to develop a series of simulation modules. The Northwestern Objective Microanastomosis Assessment Tool (NOMAT) was created as the corresponding assessment tool for the Congress of Neurosurgical Surgeons Microanastomosis Module. The face and construct validity of the NOMAT have been previously established.

OBJECTIVE

To further validate the NOMAT by determining its interrater reliability (IRR) between raters of varying levels of microsurgical expertise.

METHODS

The NOMAT was used to assess residents' performance in a microanastomosis simulation module in 2 settings: Northwestern University and the Society of Neurological Surgeons 2014 Boot Camp at the University of Indiana. At Northwestern University, participants were scored by 2 experienced microsurgeons. At the University of Indiana, participants were scored by 2 postdoctoral fellows and an experienced microsurgeon. The IRR of NOMAT was estimated by computing the intraclass correlation coefficient using SPSS v22.0 (IBM, Armonk, New York).

RESULTS

A total of 75 residents were assessed. At Northwestern University, 21 residents each performed microanastomosis on 2 model vessels of different sizes, one 3 mm and one 1 mm. At the University of Indiana, 54 residents performed a single microanastomosis procedure on 3-mm vessels. The intraclass correlation coefficient of the total NOMAT scores was 0.88 at Northwestern University and 0.78 at the University of Indiana.

CONCLUSION

This study indicates high IRR for the NOMAT. These results suggest that the use of raters with varying levels of expertise does not compromise the precision or validity of the scale. This allows for a wider adoption of the scale and, hence, a greater potential educational impact.

Validity Evidence for the Neuro-Endoscopic Ventriculostomy Assessment Tool (NEVAT)

BACKGROUND

Growing demand for transparent and standardized methods for evaluating surgical competence prompted the construction of the Neuro-Endoscopic Ventriculostomy Assessment Tool (NEVAT).

OBJECTIVE

To provide validity evidence of the NEVAT by reporting on the tool's internal structure and its relationship with surgical expertise during simulation-based training.

METHODS

The NEVAT was used to assess performance of trainees and faculty at an international neuroendoscopy workshop. All participants performed an endoscopic third ventriculostomy (ETV) on a synthetic simulator. Participants were simultaneously scored by 2 raters using the NEVAT procedural checklist and global rating scale (GRS). Evidence of internal structure was collected by calculating interrater reliability and internal consistency of raters' scores. Evidence of relationships with other variables was collected by comparing the ETV performance of experts, experienced trainees, and novices using Jonckheere's test (evidence of construct validity).

RESULTS

Thirteen experts, 11 experienced trainees, and 10 novices participated. The interrater reliability by the intraclass correlation coefficient for the checklist and GRS was 0.82 and 0.94, respectively. Internal consistency (Cronbach's α) for the checklist and the GRS was 0.74 and 0.97, respectively. Median scores with interquartile range on the checklist and GRS for novices, experienced trainees, and experts were 0.69 (0.58-0.86), 0.85 (0.63-0.89), and 0.85 (0.81-0.91) and 3.1 (2.5-3.8), 3.7 (2.2-4.3) and 4.6 (4.4-4.9), respectively. Jonckheere's test showed that the median checklist and GRS score increased with performer expertise ( P = .04 and .002, respectively).

CONCLUSION

This study provides validity evidence for the NEVAT to support its use as a standardized method of evaluating neuroendoscopic competence during simulation-based training.