New anatomical simulator for pediatric neuroendoscopic practice

Neurosurgical simulation models developed in Latin America and the Caribbean: a scoping review

Simulation training is an educational tool that provides technical and cognitive proficiency in a risk-free environment. Several models have recently been presented in Latin America and the Caribbean (LAC). However, many of them were presented in non-indexed literature and not included in international reviews. This scoping review aims to describe the simulation models developed in LAC for neurosurgery training. Specifically, it focuses on assessing the models developed in LAC, the simulated neurosurgical procedures, the model's manufacturing costs, and the translational outcomes. Simulation models developed in LAC were considered, with no language or time restriction. Cadaveric, ex vivo, animal, synthetic, and virtual/augmented reality models were included for cranial and spinal procedures. We conducted a review according to the PRISMA-ScR, including international and regional reports from indexed and non-indexed literature. Two independent reviewers screened articles. Conflicts were resolved by a third reviewer using Covidence software. We collected data regarding the country of origin, recreated procedure, type of model, model validity, and manufacturing costs. Upon screening 917 studies, 69 models were developed in LAC. Most of them were developed in Brazil (49.28%). The most common procedures were related to general neurosurgery (20.29%), spine (17.39%), and ventricular neuroendoscopy and cerebrovascular (15.94% both). Synthetic models were the most frequent ones (38.98%). The manufacturing cost ranged from 4.00 to 2005.00 US Dollars. To our knowledge, this is the first scoping review about simulation models in LAC, setting the basis for future research studies. It depicts an increasing number of simulation models in the region, allowing a wide range of neurosurgical training in a resource-limited setting.

Craniotomy Simulator with Force Myography and Machine Learning-Based Skills Assessment

Craniotomy is a fundamental component of neurosurgery that involves the removal of the skull bone flap. Simulation-based training of craniotomy is an efficient method to develop competent skills outside the operating room. Traditionally, an expert surgeon evaluates the surgical skills using rating scales, but this method is subjective, time-consuming, and tedious. Accordingly, the objective of the present study was to develop an anatomically accurate craniotomy simulator with realistic haptic feedback and objective evaluation of surgical skills. A CT scan segmentation-based craniotomy simulator with two bone flaps for drilling task was developed using 3D printed bone matrix material. Force myography (FMG) and machine learning were used to automatically evaluate the surgical skills. Twenty-two neurosurgeons participated in this study, including novices (n = 8), intermediates (n = 8), and experts (n = 6), and they performed the defined drilling experiments. They provided feedback on the effectiveness of the simulator using a Likert scale questionnaire on a scale ranging from 1 to 10. The data acquired from the FMG band was used to classify the surgical expertise into novice, intermediate and expert categories. The study employed naïve Bayes, linear discriminant (LDA), support vector machine (SVM), and decision tree (DT) classifiers with leave one out cross-validation. The neurosurgeons' feedback indicates that the developed simulator was found to be an effective tool to hone drilling skills. In addition, the bone matrix material provided good value in terms of haptic feedback (average score 7.1). For FMG-data-based skills evaluation, we achieved maximum accuracy using the naïve Bayes classifier (90.0 ± 14.8%). DT had a classification accuracy of 86.22 ± 20.8%, LDA had an accuracy of 81.9 ± 23.6%, and SVM had an accuracy of 76.7 ± 32.9%. The findings of this study indicate that materials with comparable biomechanical properties to those of real tissues are more effective for surgical simulation. In addition, force myography and machine learning provide objective and automated assessment of surgical drilling skills.

International Women in Neurosurgery

The history of women in neurosurgery worldwide has been characterized by adversity and hardships in a male-dominated field, where resilient, tenacious, and ingenious women have nevertheless left their mark. The first women in neurosurgery appeared in Europe at the end of the 1920s, and since then have emerged in all continents in the world. Women neurosurgeons all over the globe have advanced the field in numerous directions, introducing neurosurgical subspecialties to their countries, making scientific and technical advances, and dedicating themselves to humanitarian causes, to name a few. The past 30 years, in particular, have been a period of increasing involvement and responsibility for women in neurosurgery. We must now focus on continual system improvements that will promote a diverse and talented workforce, building a welcoming environment for all aspiring neurosurgeons, in order to advance the specialty in the service of neurosurgical patients.

The utilisation of 3D printing in paediatric neurosurgery

3D printing technology has evolved over the years and there is a growing interest in its application in paediatric neurosurgery. Modern 3D printers have enabled the development of patient-specific 3D models that provide a realistic representation of complex anatomies and will aid in planning complex procedures. Paediatric neurosurgical operations are challenging and hands-on training is restricted. Surgical simulation training with biomodel has provided a new paradigm for trainees to master their surgical skills before encountering similar scenarios in real-life environment. This paper reviews the aspects of 3D printing for preoperative planning and simulation-based surgical training in paediatric neurosurgery.

Progress in neurosurgery: Contributions of women neurosurgeons in Latin America

Nearly 75 years after the first woman neurosurgeon was trained in Latin America, the field of neurosurgery is changing and the prominence of women neurosurgeons within the specialty is increasing. By researching the histories of individual physicians and neurosurgeons, as well as neurosurgical departments and societies, we present, for the first time, the history of the women in neurosurgery in Latin America. Women neurosurgeons in the region have made notable progress, inspiring subsequent generations and actively participating in organized neurosurgery, medical leadership outside neurosurgery, academic neurosurgery, and leadership in contemporary society. The establishment of "Women in Neurosurgery" networks and organizations has been important to the success of many of these efforts. This collaborative study, which identifies the known women neurosurgeons in Latin America for the first time, may serve to provide background and context for further contributions of women neurosurgeons for our profession and our patients.

Development and evaluation of a patient-specific surgical simulator for endoscopic colloid cyst resection

OBJECTIVE

Endoscopic resection of third-ventricle colloid cysts is technically challenging due to the limited dexterity and visualization provided by neuroendoscopic instruments. Extensive training and experience are required to master the learning curve. To improve the education of neurosurgical trainees in this procedure, a synthetic surgical simulator was developed and its realism, procedural content, and utility as a training instrument were evaluated.

METHODS

The simulator was developed based on the neuroimaging (axial noncontrast CT and T1-weighted gadolinium-enhanced MRI) of an 8-year-old patient with a colloid cyst and hydrocephalus. Image segmentation, computer-aided design, rapid prototyping (3D printing), and silicone molding techniques were used to produce models of the skull, brain, ventricles, and colloid cyst. The cyst was filled with a viscous fluid and secured to the roof of the third ventricle. The choroid plexus and intraventricular veins were also included. Twenty-four neurosurgical trainees performed a simulated colloid cyst resection using a 30° angled endoscope, neuroendoscopic instruments, and image guidance. Using a 19-item feedback survey (5-point Likert scales), participants evaluated the simulator across 5 domains: anatomy, instrument handling, procedural content, perceived realism, and confidence and comfort level.

RESULTS

Participants found the simulator's anatomy to be highly realistic (mean 4.34 ± 0.63 [SD]) and appreciated the use of actual instruments (mean 4.38 ± 0.58). The procedural content was also rated highly (mean 4.28 ± 0.77); however, the perceived realism was rated slightly lower (mean 4.08 ± 0.63). Participants reported greater confidence in their ability to perform an endoscopic colloid cyst resection after using the simulator (mean 4.45 ± 0.68). Twenty-three participants (95.8%) indicated that they would use the simulator for additional training. Recommendations were made to develop complex case scenarios for experienced trainees (normal-sized ventricles, choroid plexus adherent to cyst wall, bleeding scenarios) and incorporate advanced instrumentation such as side-cutting aspiration devices.

CONCLUSIONS

A patient-specific synthetic surgical simulator for training residents and fellows in endoscopic colloid cyst resection was successfully developed. The simulator's anatomy, instrument handling, and procedural content were found to be realistic. The simulator may serve as a valuable educational tool to learn the critical steps of endoscopic colloid cyst resection, develop a detailed understanding of intraventricular anatomy, and gain proficiency with bimanual neuroendoscopic techniques.

Development of a Technical Skills Test to Improve Assessment and Evaluation in Neuroendoscopic Education

BACKGROUND

Endoscopy requires a unique set of skills that are difficult to acquire in most training programs. A method to test technical skills, in a validated manner, has rarely been attempted. The purpose of this study was to develop a technical skills examination for objective assessment in neuroendoscopic education.

METHODS

Twenty-nine participants were included for analysis and divided by seniority level into 2 groups defined as before or upon postgraduation year (PGY) 5 (n = 18, junior surgeons) or after PGY5 (n = 11, senior surgeons). Study participants were assessed for baseline performance and then again following a 4-hour neuroendoscopy course. Wilcoxon test was used to evaluate for performance differences between cohorts. Correlation analyses were performed using the Pearson or Spearman coefficient.

RESULTS

Increasing PGY level was correlated with a decreased average time to complete all 3 tasks (r = -0.44, P = 0.03) at baseline. Overall performance improved in both cohorts following the course (P < 0.001). When comparing junior surgeons after endoscopy training (posttest) to senior surgeons at their baseline (pretest), the junior surgeons were faster after endoscopic training than the senior surgeons were before training (P < 0.001).

CONCLUSIONS

A neuroendoscopic skills test can distinguish between more or less experienced surgeons. Significant overall performance improvement, regardless of seniority level, following neuroendoscopic training demonstrates the accuracy of the test at detecting operating improvement in all stages of learning.

Development and Evaluation of Pediatric Mixed-Reality Model for Neuroendoscopic Surgical Training

OBJECTIVE

Neurosurgical training requires several years of supervised procedures and represents a long and challenging process. The development of surgical simulation platforms is essential to reducing the risk of potentially intraoperative severe errors arising from inexperience. To present and perform a phase I validation process of a mixed reality simulation (realistic and virtual simulators combined) for neuroendoscopic surgical training.

METHODS

Tridimensional videos were developed by the 3DS Max program. Physical simulators were made with a synthetic thermoretractile and thermosensible rubber, which, when combined with different polymers, produces >30 different textures that simulate consistencies and mechanical resistance of human tissues. Questionnaires regarding the role of virtual and realistic simulators were applied to experienced neurosurgeons to assess the applicability of the mixed-reality simulation for neuroendoscopic surgical training.

RESULTS

The model was considered as a potential tool for training new residents in neuroendoscopic surgery. It was also adequate for practical application with inexperienced surgeons. According to the overall score, 83% of the surgeons believed that the realistic physical simulator presents distortions when compared with the real anatomic structure, afterwards the model improved 66% tridimensional reconstruction and 66% reported that the virtual simulator allowed a multiangular perspective ability.

CONCLUSIONS

This model provides a highly effective way of working with 3-dimensional data and significantly enhances the learning of surgical anatomy and operative strategies. The combination of virtual and realistic tools may safely improve and abbreviate the surgical learning curve.

Development and validation of a synthetic 3D-printed simulator for training in neuroendoscopic ventricular lesion removal

OBJECTIVE

Neuroendoscopic surgery using an ultrasonic aspirator represents a valid tool with which to perform the safe resection of deep-seated ventricular lesions, but the handling of neuroendoscopic instruments is technically challenging, requiring extensive training to achieve a steep learning curve. Simulation-based methods are increasingly used to improve surgical skills, allowing neurosurgical trainees to practice in a risk-free, reproducible environment. The authors introduce a synthetic, patient-specific simulator that enables trainees to develop skills for endoscopic ventricular tumor removal, and they evaluate the model’s validity as a training instrument with regard to realism, mechanical proprieties, procedural content, and handling.

METHODS

The authors developed a synthetic simulator based on a patient-specific CT data set. The anatomical features were segmented, and several realistic 1:1 skull models with all relevant ventricular structures were fabricated by a 3D printer. Vascular structures and the choroid plexus were included. A tumor model, composed of polyvinyl alcohol, mimicking a soft-consistency lesion, was secured in different spots of the frontal horn and within the third ventricle. Neurosurgical trainees participating in a neuroendoscopic workshop qualitatively assessed, by means of a feedback survey, the properties of the simulator as a training model that teaches neuroendoscopic ultrasonic ventricular tumor surgery; the trainees rated 10 items according to a 5-point Likert scale.

RESULTS

Participants appreciated the model as a valid hands-on training tool for neuroendoscopic ultrasonic aspirator tumor removal, highly rating the procedural content. Furthermore, they mostly agreed on its comparably realistic anatomical and mechanical properties. By the model’s first application, the authors were able to recognize possible improvement measures, such as the development of different tumor model textures and the possibility, for the user, of creating a realistic surgical skull approach and neuroendoscopic trajectory.

CONCLUSIONS

A low-cost, patient-specific, reusable 3D-printed simulator for the training of neuroendoscopic ultrasonic aspirator tumor removal was successfully developed. The simulator is a useful tool for teaching neuroendoscopic techniques and provides support in the development of the required surgical skills.

A Review of Physical Simulators for Neuroendoscopy Skills Training

BACKGROUND

Minimally invasive neurosurgical approaches reduce patient morbidity by providing the surgeon with better visualization and access to complex lesions, with minimal disruption to normal anatomy. The use of rigid or flexible neuroendoscopes, supplemented with a conventional stereoscopic operating microscope, has been integral to the adoption of these techniques. Neurosurgeons commonly use neuroendoscopes to perform the ventricular and endonasal approaches. It is challenging to learn neuroendoscopy skills from the existing apprenticeship model of surgical education. The training methods, which use simulation-based systems, have achieved wide acceptance. Physical simulators provide anatomic orientation and hands-on experience with repeatability. Our aim is to review the existing physical simulators on the basis of the skills training of neuroendoscopic procedures.

METHODS

We searched Scopus, Google Scholar, PubMed, IEEE Xplore, and dblp. We used the following keywords "neuroendoscopy," "training," "simulators," "physical," and "skills evaluation." A total of 351 articles were screened based on development methods, evaluation criteria, and validation studies on physical simulators for skills training in neuroendoscopy.

RESULTS

The screening of the articles resulted in classifying the physical training methods developed for neuroendoscopy surgical skills into synthetic simulators and box trainers. The existing simulators were compared based on their design, fidelity, trainee evaluation methods, and validation studies.

CONCLUSIONS

The state of simulation systems demands collaborative initiatives among translational research institutes. They need improved fidelity and validation studies for inclusion in the surgical educational curriculum. Learning should be imparted in stages with standardization of performance metrics for skills evaluation.

New Simulator for Neuroendoscopy: A Realistic and Attainable Model

OBJECTIVE

To present an attainable and realistic model for neuroendoscopic simulation which replicates exercises of tissue biopsy and coagulation and membrane fenestration.

METHODS

We presented a stepwise method to create a neuroendoscopic simulation model using bovine brain and membrane units made by a soda cup covered by an amniotic membrane inside an expanded polystyrene spherical container. We used face validation for preliminary evaluation. We also rated the students before and after training with the NEVAT global rating scale (GRS) and recorded the time required to complete all 3 procedures (third ventriculostomy, tissue biopsy, and coagulation). The total cost of the model was $5.

RESULTS

The experts consider this new model as capable of reproducing real surgical situations with great similarity to the human brain. We tested the model in 20 trainees. The median GRS score before the training was 9 (range, 7-12). After repeated training and performance feedback, the final median GRS score was 41 (range, 37.5-45; P < 0.0001). The time needed to finish the exercises before training was 33 minutes (range, 30.5-42.5 minutes), and after using the model the final median time was 20 minutes (range, 17.5-22 minutes; P < 0.0001).

CONCLUSIONS

Simulators for neuroendoscopy described so far are reliable, but they entail a high cost. Models with live animals, although of lower cost, are questioned from an ethical point of view. In the current work, we describe a high fidelity ventricular neuroendoscopic simulator model that, because of its low cost, can be replicated in any training center that has a neuroendoscope.

Development and evaluation of a new pediatric mixed-reality model for neurosurgical training

OBJECTIVE

Craniosynostosis is a premature cranial suture junction and requires a craniectomy to decrease cranial compression and remodel the affected areas of the skull. However, mastering these neurosurgical procedures requires many years of supervised training. The use of surgical simulation can reduce the risk of intraoperative error. The authors propose a new instrument for neurosurgical education, which mixes reality with virtual and realistic simulation for repair of craniosynostosis (scaphocephaly type).

METHODS

This study tested reality simulators with a synthetic thermo-retractile/thermosensitive rubber joined with different polymers. To validate the model, 18 experienced surgeons participated in this study using 3D videos developed using 3DS Max software. Renier's "H" technique for craniosynostosis correction was applied during the simulation. All participants completed questionnaires to evaluate the simulator.

RESULTS

An expert surgical team approved the craniosynostosis reality and virtual simulators. More than 94% of participants found the simulator relevant, considering aspects such as weight, surgical positioning, dissection by planes, and cranial reconstruction. The consistency and material resistance were also approved on average by more than 60% of the surgeons.

CONCLUSIONS

The virtual simulator demands a high degree of effectiveness with 3D perception in anatomy and operative strategies in neurosurgical training. Physical and virtual simulation with mixed reality required psychomotor and cognitive abilities otherwise acquired only during practical surgical training with supervision.

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.

The Role of Mixed Reality Simulation for Surgical Training in Spine: Phase 1 Validation

STUDY DESIGN

This study shows the first phase of validation of a new model for realistic training on spine surgery, conducted from January 2014 to November 2015.

OBJECTIVE

To propose and validate a new tool for neurosurgical education, associating virtual and realistic simulation (mixed reality), for spine surgery.

SUMMARY OF BACKGROUND DATA

Surgical simulation is a relatively new filed that has a lot to offer to neurosurgical education. Training a new surgeon may take years of hands-on procedures, increasing the risk to patient's safety. The development of surgical simulation platforms is therefore essential to reducing the risk of potentially serious risks and improving outcome.

METHODS

Sixteen experienced spinal surgeons evaluated these simulators and answered the questionnaire regarding the simulation as a beneficial education tool. They evaluated the simulators in regard to dissection by planes, identification of pathology (lumbar canal stenosis), instrumentation and simulation of cerebrospinal fluid (CSF) leak, and the relevant aspects of the computerized tomography (CT) imaging.

RESULTS

The virtual and physical simulators for spine surgery were approved by an expert surgery team, and considered adequate for educational purposes. The proportion of the answers was estimated by the confidence intervals.

CONCLUSION

The surgery team considered that this virtual simulation provides a highly effective training environment, and it significantly enhances teaching of surgical anatomy and operative strategies in the neurosurgical field. A mixture of physical and virtual simulation provided the desired results of enhancing the requisite psychomotor and cognitive skills, previously acquired only during a surgical apprenticeship. The combination of these tools may potentially improve and abbreviate the learning curve for trainees, in a safe environment.

LEVEL OF EVIDENCE

3.

Low-cost endoscopic third ventriculostomy simulator with mimetic endoscope

OBJECTIVE Hydrocephalus affects approximately 1 in 500 people in the US, yet ventricular shunting, the gold standard of treatment, has a nearly 85% failure rate. Endoscopic third ventriculostomy (ETV) is an alternative surgical approach for a specific subset of hydrocephalic patients, but can be limited by the inability of neurosurgical residents to practice prior to patient contact. The goal of this study was to create an affordable ETV model and endoscope for resident training. METHODS Open-source software was used to isolate the skull and brain from the CT and MR images of a 2-year-old boy with hydrocephalus. A 3D printer created the skull and a 3D mold of the brain. A mixture of silicone and silicone tactile mutator was used to cast the brain mold prior to subsequent compression and shearing modulus testing. A mimetic endoscope was then created from basic supplies and a 3D printed frame. A small cohort of neurosurgical residents and attending physicians evaluated the ETV simulator with mimetic endoscope. RESULTS The authors successfully created a mimetic endoscope and ETV simulator. After compression and shearing modulus testing, a silicone/Slacker ratio between 10:6 and 10:7 was found to be similar to that of human brain parenchyma. Eighty-seven percent of participants strongly agreed that the simulator was useful for resident training, and 93% strongly agreed that the simulator helped them understand how to orient themselves with the endoscope. CONCLUSIONS The authors created an affordable (US$123, excluding 3D printer), easy-to-use ETV simulator with endoscope. Previous models have required expensive software and costly operative endoscopes that may not be available to most residents. Instead, this attempt takes advantage of open-source software for the manipulation and fabrication of a patient-specific mold. This model can assist with resident development, allowing them to safely practice use of the endoscope in ETV.