Quality assessment of a new surgical simulator for neuroendoscopic training

Feasibility of Augmented Reality for Pediatric Giant Supratentorial Tumors: A Report of Three Cases

Giant supratentorial brain tumors (GSBTs) in children are uncommon and extremely challenging entities unique to pediatric neurosurgery. Factors such as young patient age, need for urgent intervention, intraoperative blood loss, and ongoing raised intracranial pressure symptoms are examples of difficulties faced. Recently, there has been a growing body of literature on augmented reality (AR) in adult neurosurgery. In contrast, the use of AR in pediatric neurosurgery is comparatively less. Nonetheless, we postulate that AR systems will be helpful for understanding spatial relationships of complex GSBT anatomy for preoperative planning in a timely fashion. This study describes our experience in trialing AR as a potential tool for three cases of pediatric GSBTs. Overall, the AR platform offers our neurosurgical team excellent visuospatial insights for preoperative decision-making. However, we observe that substantial time is required to set up the AR system prior to each clinical case discussion by the neurosurgical team. In congruency with existing literature, our preliminary results report that there are still obstacles that need to be addressed before the technology can be seamlessly implemented into the clinical workflow for these time-sensitive childhood brain tumors. To our knowledge, this is the first study to report the potential use of AR for complex pediatric GSBT cases.

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.

Development and evaluation of a 3d printed training model for endoscopic third ventriculostomy in low-income countries

Introduction

Pediatric hydrocephalus is highly prevalent and therefore a major neurosurgical problem in Africa. In addition to ventriculoperitoneal shunts, which have high cost and potential complications, endoscopic third ventriculostomy is becoming an increasingly popular technique especially in this part of the world. However, performing this procedure requires trained neurosurgeons with an optimal learning curve. For this reason, we have developed a 3D printed training model of hydrocephalus so that neurosurgeons without previous experience with endoscopic techniques can acquire these skills, especially in low-income countries, where specific techniques training as this, are relatively absent.

Research Question

Our research question was about the possibility to develop and produce a low-cost endoscopic training model and to evaluate the usefulness and the skills acquired after training with it.

Material and Methods

A neuroendoscopy simulation model was developed. A sample of last year medical students and junior neurosurgery residents without prior experience in neuroendoscopy were involved in the study. The model was evaluated by measuring several parameters, as procedure time, number of fenestration attempts, diameter of the fenestration, and number of contacts with critical structures.

Results

An improvement of the average score on the ETV-Training-Scale was noticed between the first and last attempt (11.6, compared to 27.5 points; p<0.0001). A statistically significant improvement in all parameters, was observed.

Discussion and Conclusion

This 3D printed simulator facilitates acquiring surgical skills with the neuroendoscope to treat hydrocephalus by performing an endoscopic third ventriculostomy. Furthermore, it has been shown to be useful to understand the intraventricular anatomical relationships.

Development of a 3D Printed Brain Model with Vasculature for Neurosurgical Procedure Visualisation and Training

BACKGROUND

Simulation-based techniques using three-dimensional models are gaining popularity in neurosurgical training. Most pre-existing models are expensive, so we felt a need to develop a real-life model using 3D printing technology to train in endoscopic third ventriculostomy.

METHODS

The brain model was made using a 3D-printed resin mold from patient-specific MRI data. The mold was filled with silicone Ecoflex™ 00-10 and mixed with Silc Pig^® pigment additives to replicate the color and consistency of brain tissue. The dura mater was made from quick-drying silicone paste admixed with gray dye. The blood vessels were made from a silicone 3D-printed mold based on magnetic resonance imaging. Liquid containing paprika oleoresin dye was used to simulate blood and was pumped through the vessels to simulate pulsatile motion.

RESULTS

Seven residents and eight senior neurosurgeons were recruited to test our model. The participants reported that the size and anatomy of the elements were very similar to real structures. The model was helpful for training neuroendoscopic 3D perception and navigation.

CONCLUSIONS

We developed an endoscopic third ventriculostomy training model using 3D printing technology that provides anatomical precision and a realistic simulation. We hope our model can provide an indispensable tool for young neurosurgeons to gain operative experience without exposing patients to risk.

Magnetic resonance imaging based neurosurgical planning on hololens 2: A feasibility study in a paediatric hospital

Objective

The goal of this work is to show how to implement a mixed reality application (app) for neurosurgery planning based on neuroimaging data, highlighting the strengths and weaknesses of its design.

Methods

Our workflow explains how to handle neuroimaging data, including how to load morphological, functional and diffusion tensor imaging data into a mixed reality environment, thus creating a first guide of this kind. Brain magnetic resonance imaging data from a paediatric patient were acquired using a 3 T Siemens Magnetom Skyra scanner. Initially, this raw data underwent specific software pre-processing and were subsequently transformed to ensure seamless integration with the mixed reality app. After that, we created three-dimensional models of brain structures and the mixed reality environment using Unity™ engine together with Microsoft® HoloLens 2™ device. To get an evaluation of the app we submitted a questionnaire to four neurosurgeons. To collect data concerning the performance of a user session we used Unity Performance Profiler.

Results

The use of the interactive features, such as rotating, scaling and moving models and browsing through menus, provided by the app had high scores in the questionnaire, and their use can still be improved as suggested by the performance data collected. The questionnaire's average scores were high, so the overall experiences of using our mixed reality app were positive.

Conclusion

We have successfully created a valuable and easy-to-use neuroimaging data mixed reality app, laying the foundation for more future clinical uses, as more models and data derived from various biomedical images can be imported.

Simulation training in endoscopic skull base surgery: A scoping review

Objective

Methods

Results

Conclusions

The evolution of an SBNS-accredited NANSIG simulated skills workshop for aspiring neurosurgical trainees: an analysis of qualitative and quantitative data

Background

The Neurology and Neurosurgery Interest Group (NANSIG) neurosurgical skills workshop is novel in teaching neurosurgical skills solely to medical students and foundation trainees in the UK. The aim is to offer an affordable option for a high-fidelity simulation course enabling students to learn and practise specific neurosurgical skills in a safe, supervised environment.

Methods

A 10-delegate cohort was quantitatively assessed at the NANSIG neurosurgical skills workshop. Two assessors used a novel modified Objective Structured Assessment of Technical Skills (mOSATS) assessment tool, comprising 5 domains ranked according to a 5-point scale to rate delegates’ ability to create a burr hole. Qualitative data from previous workshops were collected, consisting of open-ended, closed-ended and 5-point Likert scale responses to pre- and post-workshop questionnaires. Data were analysed using SPSS® software.

Results

Delegates scored a mean total of 62.1% (21.75/35) and 85.1% (29.8/35) in pre- and post-workshop assessments respectively revealing a statistically significant improvement. Regarding percentage of improvement, no significant difference was shown amongst candidates when comparing the number of neurosurgical cases observed and/or assisted in the past. There was no significant difference in the overall rating between the last two workshops (4.89 and 4.8 out of 5, respectively). One hundred percent of the attendees reported feeling more confident in assisting in theatre after the last two workshops.

Conclusion

We show that a simulation workshop cannot only objectively quantify the improvement of surgical skill acquisition but can also be beneficial regardless of the extent of prior experience.

A Practical 3D-Printed Model for Training of Endoscopic and Exoscopic Intracerebral Hematoma Surgery with a Tubular Retractor

OBJECTIVE

 To present a three-dimensional (3D)-printed model that simulates endoscopic and exoscopic intracerebral hematoma (ICH) surgery with a tubular retractor.

METHODS

 We used 3D printing technology to develop the model that consisted of the skull frame and a replaceable inserted module. Edible gelatin and animal blood were placed into the module to mimic brain tissue and the hematoma. Twenty neurosurgeons were recruited to participate in our training program that required the use of an endoscope and an exoscope to aspirate the hematoma with a tubular retractor. Five postgraduates were asked to complete the entire training with the endoscope five times. Questionnaires were distributed for feedback after the training program.

RESULTS

 The more experienced surgeons obviously performed better than the rather inexperienced surgeons, verifying that our model could reflect the ability of the trainees. As the training progressed, the scores of the postgraduates increased, and the average score of the fifth training was obviously higher than the first score. No significant differences were observed in the trainees' performance with the endoscope and the exoscope. The feedback questionnaires showed the average score for value of the simulator as a training tool was a 3.65 (on a 4-point scale). Our model received better comments regarding the bone texture (mean: 3.20), the brain tissue texture (mean: 3.20), and the experience in aspirating the hematoma (mean: 3.10). The surgical position (mean: 2.95), surgical approach (mean: 2.90), and simulated brain tissue (mean: 2.85) should be improved.

CONCLUSION

 Our model was practical for endoscopic and exoscopic ICH surgery training. The results of our program showed that prior surgical experience benefited the mastery of both the endoscopic and the exoscopic ICH surgery in the 3D-printed model. Our model could make mastering basic skills more efficient.

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.

Design and validation of a 3D-printed simulator for endoscopic third ventriculostomy

BACKGROUND

Simulation-based training has been considered as the most promising curriculum for neurosurgical education to finally improve surgical skills with the greatest efficiency and safety. However, most of the simulators including physical models and virtual reality systems are relatively expensive, which limits their promotion. In this study, the authors tried to develop a realistic, low-cost, and reusable simulator for endoscopic third ventriculostomy (ETV) and evaluate its validity.

METHODS

A 3D-printed rigid skull with the ventricular system originated from a de-identified patient with obstructive hydrocephalus was constructed. The third ventricular floor was designed as a replaceable module. Thirty-nine neurosurgeons tested the simulator and a rating system was established to assess their performance. All participants filled out questionnaires to evaluate the simulator after training. Five neurosurgical students were recruited to finish the whole training for ten times in order to explore the learning curve of ETV.

RESULTS

We found that (1) the more experienced surgeons performed obviously better than the rather inexperienced surgeons which verified that our model could reflect the ability of the trainees; (2) as the training progressed, the scores of the post-graduates increased and the fifth training average score was obviously higher than their first training average score. The feedback questionnaires showed the average scores for value of the simulator as a training tool and global rating were 3.15 and 3.54 (on a 4-point scale).

CONCLUSION

Our model was practical for ETV training. The results of our program showed that our model could precisely reflect the operators' ability to perform ETV and could make it more efficient to master basic skills.

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.

Simulation-based Education for Endoscopic Third Ventriculostomy: A Comparison Between Virtual and Physical Training Models

BACKGROUND

The relative educational benefits of virtual reality (VR) and physical simulation models for endoscopic third ventriculostomy (ETV) have not been evaluated "head to head."

OBJECTIVE

To compare and identify the relative utility of a physical and VR ETV simulation model for use in neurosurgical training.

METHODS

Twenty-three neurosurgical residents and 3 fellows performed an ETV on both a physical and VR simulation model. Trainees rated the models using 5-point Likert scales evaluating the domains of anatomy, instrument handling, procedural content, and the overall fidelity of the simulation. Paired t tests were performed for each domain's mean overall score and individual items.

RESULTS

The VR model has relative benefits compared with the physical model with respect to realistic representation of intraventricular anatomy at the foramen of Monro (4.5, standard deviation [SD] = 0.7 vs 4.1, SD = 0.6; P = .04) and the third ventricle floor (4.4, SD = 0.6 vs 4.0, SD = 0.9; P = .03), although the overall anatomy score was similar (4.2, SD = 0.6 vs 4.0, SD = 0.6; P = .11). For overall instrument handling and procedural content, the physical simulator outperformed the VR model (3.7, SD = 0.8 vs 4.5; SD = 0.5, P < .001 and 3.9; SD = 0.8 vs 4.2, SD = 0.6; P = .02, respectively). Overall task fidelity across the 2 simulators was not perceived as significantly different.

CONCLUSION

Simulation model selection should be based on educational objectives. Training focused on learning anatomy or decision-making for anatomic cues may be aided with the VR simulation model. A focus on developing manual dexterity and technical skills using endoscopic equipment in the operating room may be better learned on the physical simulation model.

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.

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.

Developing a dynamic simulator for endoscopic intraventricular surgeries

INTRODUCTION

A novel dynamic simulator brain model with hydrocephalus has been developed for endoscopic intraventricular procedures. Detachable components allow enhancement of the walls of the ventricle by choroid plexus, ependymal veins and the membranous floor of the third ventricle which are derived from cadaveric lab animal tissues to give a lifelike appearance. These can be changed for every exercise. Ventricles are filled with injection of saline to give appropriate transparent medium and connected to a device transmitting pulsations creating conditions similar to live surgeries.

MATERIAL AND METHODS

Thirty-five participants have used this model over the last 1 year and found it to be useful for conducting third ventriculostomy. Further development of the model for septostomy, aqueductoplasty and tumour biopsy has also been recently tested successfully by 12 participants.

CONCLUSION

It is hoped that this simulator model for intraventricular endoscopy is comprehensive as a learning tool in carrying out most of the the surgical procedures currently practised.

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.

Patient-specific neurosurgical phantom: assessment of visual quality, accuracy, and scaling effects

BACKGROUND

Training in medical education depends on the availability of standardized materials that can reliably mimic the human anatomy and physiology. One alternative to using cadavers or animal bodies is to employ phantoms or mimicking devices. Styrene-ethylene/butylene-styrene (SEBS) gels are biologically inert and present tunable properties, including mechanical properties that resemble the soft tissue. Therefore, SEBS is an alternative to develop a patient-specific phantom, that provides real visual and morphological experience during simulation-based neurosurgical training.

RESULTS

A 3D model was reconstructed and printed based on patient-specific magnetic resonance images. The fused deposition of polyactic acid (PLA) filament and selective laser sintering of polyamid were used for 3D printing. Silicone and SEBS materials were employed to mimic soft tissues. A neuronavigation protocol was performed on the 3D-printed models scaled to three different sizes, 100%, 50%, and 25% of the original dimensions. A neurosurgery team (17 individuals) evaluated the phantom realism as "very good" and "perfect" in 49% and 31% of the cases, respectively, and rated phantom utility as "very good" and "perfect" in 61% and 32% of the cases, respectively. Models in original size (100%) and scaled to 50% provided a quantitative and realistic visual analysis of the patient's cortical anatomy without distortion. However, reduction to one quarter of the original size (25%) hindered visualization of surface details and identification of anatomical landmarks.

CONCLUSIONS

A patient-specific phantom was developed with anatomically and spatially accurate shapes, that can be used as an alternative for surgical planning. Printed models scaled to sizes that avoided quality loss might save time and reduce medical training costs.

Indigenous Inexpensive Practice Models for Skill Development in Neuroendoscopy

Introduction:

Neurosurgery is a branch having a tough learning curve. Residents generally get very less hands-on exposure for advanced procedures like neuroendoscopy. With the limited number of cadavers available and ethical issues associated with animal models, practice models, and simulators are becoming the able alternative. Most of these simulators are very costly. We tried to build indigenous inexpensive practice models that can help in developing most of the skills of neuroendoscopy.

Materials and Methods:

Models were built for learning hand-eye coordination, dexterity, instrument manipulation, cutting, fine dissection, keyhole concept, drilling, and simulation of laminectomy and ligamentum flavum resection. These were shown in the neuroendoscopic fellowship program conducted in authors' institute, and trainees' responses were recorded.

Results:

Both novice and experienced neuroendoscopic surgeons validated the models. There was no significant difference between their responses (P = 0.791).

Conclusion:

Indigenous innovative models can be used to learn and teach neuroendoscopic skills. The presented models were reliable, valid, eco-friendly, highly cost-effective, portable, easily made and can be kept in one's chamber for practicing.

Resident simulation training in endoscopic endonasal surgery utilizing haptic feedback technology

Simulated practice may improve resident performance in endoscopic endonasal surgery. Using the NeuroTouch haptic simulation platform, we evaluated resident performance and assessed the effect of simulation training on performance in the operating room. First- (N=3) and second- (N=3) year residents were assessed using six measures of proficiency. Using a visual analog scale, the senior author scored subjects. After the first session, subjects with lower scores were provided with simulation training. A second simulation served as a task-learning control. Residents were evaluated in the operating room over six months by the senior author-who was blinded to the trained/untrained identities-using the same parameters. A nonparametric bootstrap testing method was used for the analysis (Matlab v. 2014a). Simulation training was associated with an increase in performance scores in the operating room averaged over all measures (p=0.0045). This is the first study to evaluate the training utility of an endoscopic endonasal surgical task using a virtual reality haptic simulator. The data suggest that haptic simulation training in endoscopic neurosurgery may contribute to improvements in operative performance. Limitations include a small number of subjects and adjudication bias-although the trained/untrained identity of subjects was blinded. Further study using the proposed methods may better describe the relationship between simulated training and operative performance in endoscopic Neurosurgery.

A practical 3D printed simulator for endoscopic endonasal transsphenoidal surgery to improve basic operational skills

PURPOSE

We aimed to present a practical three-dimensional (3D) printed simulator to comprehensively and effectively accelerate the learning curve of endoscopic endonasal transsphenoidal surgery (EETS).

METHODS

The 3D printed simulator consists of three parts: (1) skull frame, (2) the nasal passage and the nasal alar of the face, and (3) a modified sella turcica. We aimed to improve three basic operational skills of surgeons: drilling, curetting, and aspirating. Eighteen neurosurgeons and five post-graduates were recruited and consented for the training.

RESULTS

For trainees, (1) as the training progressed, the scores increased gradually, (2) a significant increase in the average scores was observed in the tenth training compared to the first training, and (3) there is a significant decrease in trainee variability in the shortening of the gap. The 18 neurosurgeons were divided into three groups: experts, assistants, and observers. For all three basic operations, (1) the average score of experts was obviously higher than that of the assistants, observers, and trainees' tenth training and (2) the average scores of assistants and observers were obviously higher than that of trainees' first training. A significant high in the average score between the assistants and the observers was seen for aspirating, but not for drilling or curetting. For curetting and aspirating, the tenth training average score of trainees was obviously higher than that of assistants and observers.

CONCLUSION

This 3D printed simulator allows different endoscopic basic operations to be simulated and improves the EETS techniques of surgeons. We believed it to be a practical, simple, and low-cost simulator.

Neurosurgical training with simulators: a novel neuroendoscopy model

PURPOSE

The aim of this study is to present a novel neuroendoscopy simulation model in live animals, with the objective of enhancing patient safety with realistic surgical training.

METHODS

A simulation model using live Wistar rats was designed after the approval of the Institutional Committee for the Care and Use of Laboratory Animals. Under anesthesia, a hydroperitoneum was created in order to simulate a cavity with mesenteric membranes and vessels, viscera, and a solid and bleeding tumor (the liver) floating in a liquid environment. For validation purposes, we evaluated trainees' basal and final skills for each neuroendoscopic procedure, and we also acknowledged trainees' and instructors' opinion on the model's realism.

RESULTS

This model is simple and low cost effective for complete and real-life training in neuroendoscopy, with the possibility of performing all the basic and advanced endoscopic procedures, such as endoscopic exploration, membrane fenestration, vessel coagulation, hematoma evacuation, and endoscopic tumor biopsy and resection using a ventricular neuroendoscopy set. Although the model does not represent human ventricular anatomy, a reliable simulation is possible in real living tissue in a liquid environment. Trainees' skills improvements were notorious.

CONCLUSION

Minimally invasive endoscopic techniques require specific training. Simulation training can improve and accelerate the learning curve. The presented training model allows simulating the different neuroendoscopic procedures. We believe that due to its practical possibilities, its simplicity, low cost, reproducibility, and reality, being live animal tissue, it can be considered a fundamental model within a complete training program on neuroendoscopy.

Neurosurgical endoscopic training via a realistic 3-dimensional model with pathology

INTRODUCTION

Training in intraventricular endoscopy is particularly challenging because the volume of cases is relatively small and the techniques involved are unlike those usually used in conventional neurosurgery. Present training models are inadequate for various reasons. Using 3-dimensional (3D) printing techniques, models with pathology can be created using actual patient's imaging data. This technical article introduces a new training model based on a patient with hydrocephalus secondary to a pineal tumour, enabling the models to be used to simulate third ventriculostomies and pineal biopsies.

METHODS

Multiple models of the head of a patient with hydrocephalus were created using 3D rapid prototyping technique. These models were modified to allow for a fluid-filled ventricular system under appropriate tension. The models were qualitatively assessed in the various steps involved in an endoscopic third ventriculostomy and intraventricular biopsy procedure, initially by 3 independent neurosurgeons and subsequently by 12 participants of an intraventricular endoscopy workshop.

RESULTS

All 3 surgeons agreed on the ease and usefulness of these models in the teaching of endoscopic third ventriculostomy, performing endoscopic biopsies, and the integration of navigation to ventriculoscopy. Their overall score for the ventricular model realism was above average. The 12 participants of the intraventricular endoscopy workshop averaged between a score of 4.0 to 4.6 of 5 for every individual step of the procedure.

DISCUSSION

Neurosurgical endoscopic training currently is a long process of stepwise training. These 3D printed models provide a realistic simulation environment for a neuroendoscopy procedure that allows safe and effective teaching of navigation and endoscopy in a standardized and repetitive fashion.

Endoscopic sinus surgery dissection courses using a real simulator: the benefits of this training

INTRODUCTION

Endonasal surgeries are among the most common procedures performed in otolaryngology. Due to difficulty in cadaver acquisition and the intrinsic risks of training residents during operations on real patients, nasosinusal endoscopic dissection courses utilizing real simulators, such as the Sinus Model Otorhino Neuro Trainer are being developed as a new technique to facilitate the acquisition of better anatomical knowledge and surgical skill.

OBJECTIVE

To evaluate the efficacy of nasosinusal endoscopic dissection courses with the Sinus Model Otorhino Neuro Trainer simulator in the training of otolaryngology surgeons.

METHODS

A prospective, longitudinal cohort study was conducted with 111 otolaryngologists who participated in a theoretical and practical course of endoscopic surgery dissection using the Sinus Model Otorhino Neuro Trainer simulator, with application of questionnaires during and after the course.

RESULTS

From the ten procedures performed utilizing the simulator, the evaluation revealed mean scores from 3.1 to 4.1 (maximum of 5). Seventy-seven participants answered the questionnaire six months after the end of the course. 93% of them reported that they could perform the procedures more safely following the course, 98% reported an improvement in their anatomical and clinical knowledge, and 85% related an improvement in their surgical ability. After the course, the number of endoscopic surgeries increased in 40% of the respondents.

CONCLUSION

Endoscopic sinus dissection courses using the Sinus Model Otorhino Neuro Trainer simulator proved to be useful in the training of otolaryngologists.

Design and Validation of an Open-Source, Partial Task Trainer for Endonasal Neuro-Endoscopic Skills Development: Indian Experience

BACKGROUND

Box trainers are ideal simulators, given they are inexpensive, accessible, and use appropriate fidelity.

OBJECTIVE

The development and validation of an open-source, partial task simulator that teaches the fundamental skills necessary for endonasal skull-base neuro-endoscopic surgery.

METHODS

We defined the Neuro-Endo-Trainer (NET) SkullBase-Task-GraspPickPlace with an activity area by analyzing the computed tomography scans of 15 adult patients with sellar suprasellar parasellar tumors. Four groups of participants (Group E, n = 4: expert neuroendoscopists; Group N, n =19: novice neurosurgeons; Group R, n = 11: neurosurgery residents with multiple iterations; and Group T, n = 27: neurosurgery residents with single iteration) performed grasp, pick, and place tasks using NET and were graded on task completion time and skills assessment scale score.

RESULTS

Group E had lower task completion times and greater skills assessment scale scores than both Group N and R (P ≤ 0.03, 0.001). The performance of Groups N and R was found to be equivalent; in self-assessing neuro-endoscopic skill, the participants in these groups were found to have equally low pretraining scores (4/10) with significant improvement shown after NET simulation (6, 7 respectively). Angled scopes resulted in decreased scores with tilted plates compared with straight plates (30° P ≤ 0.04, 45° P ≤ 0.001). With tilted plates, decreased scores were observed when we compared the 0° with 45° endoscope (right, P ≤ 0.008; left, P ≤ 0.002).

CONCLUSIONS

The NET, a face and construct valid open-source partial task neuroendoscopic trainer, was designed. Presimulation novice neurosurgeons and neurosurgical residents were described as having insufficient skills and preparation to practice neuro-endoscopy. Plate tilt and endoscope angle were shown to be important factors in participant performance. The NET was found to be a useful partial-task trainer for skill building in neuro-endoscopy.

Comparison of Intracranial Neuroendoscopic Procedures in Children versus Adults

BACKGROUND

The emphasis regarding intracranial neuroendoscopy has been traditionally advocated and focused on the role in pediatric patients, although a significant usage has developed in adult patients. In this study, we examine and contrast the role of predominantly intracranial neuroendoscopy in both a pediatric and adult population with a minimum postprocedure follow-up of 5 years.

METHODS

A retrospective review was conducted for patients in the two hospitals that manage neurosurgical care for Southern Alberta, Canada, undergoing neuroendoscopic surgery between 1994 and 2008. The pediatric group was defined as age ≤17 years and the adult group as age ≥18 years.

RESULTS

A total of 273 patients who underwent a total of 330 procedures with a mean postprocedure follow-up of 12.9 years were identified. There were 161 adult and 112 pediatric patients, and both groups underwent surgery by the same surgeons. The most common procedure was endoscopic third ventriculostomy, accounting for 55% of procedures. One postoperative death occurred in an adult patient. Endoscopic third ventriculostomy success 1-year postprocedure was 81%, with only three late-term failures. Postoperative infection was the most common serious complication (two pediatric/four adult patients). Adult and pediatric patients had similar major complication rates (4.2% vs 5.7%, p=0.547).

CONCLUSIONS

Neuroendoscopy overall had a similar role in both pediatric and adult neurosurgical populations, with the most commonly associated complication being infection. Neuroendoscopy is an important therapeutic modality in the management of appropriate adult patients.

Impact of Dynamic Endoscopy and Bimanual-Binarial Dissection in Endoscopic Endonasal Surgery Training: A Laboratory Investigation

Objective The lack of a standard technique may be a relevant issue in teaching endoscopic endonasal surgery (EES) to novice surgeons. The objective of this article is to compare different endoscope positioning and microsurgical dissection techniques in EES training. Methods A comparative trial was designed to evaluate three techniques: group A, one surgeon performing binarial two-hands dissection using an endoscope holder (rigid endoscopy); group B, two surgeons performing a combined binarial two- and three-handed dissection with one surgeon guiding the endoscope (dynamic endoscopy); and group C, two surgeons performing a binarial two-hands dissection with one surgeon dedicated to endoscope positioning and the other dedicated to a two-handed dissection. Trainees were randomly assigned to these groups and oriented to complete surgical tasks in a validated training model for EES. A global rating scale, and a specific-task checklist for EES were used to assess surgical skills. Results The mean scores of the global rating scale and the specific-task checklist were higher (p = 0.001 and 0.002, respectively) for group C, reflecting the positive impact of dynamic endoscopy and bimanual dissection on training performance. Conclusions We found that dynamic endoscopic and bimanual-binarial microdissection techniques had a significant positive impact on EES training.

New anatomical simulator for pediatric neuroendoscopic practice

INTRODUCTION

The practice of neuroendoscopic procedures requires many years of training to obtain the adequate skills to perform these operations safely. In this study, we present a new pediatric neuroendoscopic simulator that facilitates training.

DESCRIPTION OF THE SIMULATOR

This realistic simulator was built with a synthetic thermo-retractile and thermo-sensible rubber called Neoderma® which, when combined with different polymers, produces more than 30 different formulae, which present textures, consistencies, and mechanical resistances similar to many human tissues. Silicon and fiberglass molds, in the shape of the cerebral ventricles, constitute the basic structure of the neuroendoscopic training module. The module offers the possibility for practicing many basic neuroendoscopic techniques such as: navigating the ventricular system to visualize important anatomic landmarks (e.g., septal and thalamostriate veins, foramen of Monro, temporal horns, aqueduct, and fourth ventricle), performing third ventriculostomy and choroid plexus cauterization, and resecting intraventricular "tumors" that bleed.

CONCLUSION

It is important to emphasize that it is possible to perform with this simulator not only the rigid but also the flexible endoscopy, with good correspondence to reality and no risks. Notable future perspectives can be considered regarding this new pediatric simulator, for example, to improve the learning curve for nonexperienced neurosurgeons and to spread the flexible endoscopy technique.

Design and evaluation of a new synthetic brain simulator for endoscopic third ventriculostomy

OBJECT

Endoscopic third ventriculostomy (ETV) is an effective but technically demanding procedure with significant risk. Current simulators, including human cadavers, animal models, and virtual reality systems, are expensive, relatively inaccessible, and can lack realistic sensory feedback. The purpose of this study was to construct a realistic, low-cost, reusable brain simulator for ETV and evaluate its fidelity.

METHODS

A brain silicone replica mimicking normal mechanical properties of a 4-month-old child with hydrocephalus was constructed, encased in the replicated skull, and immersed in water. Realistic intraventricular landmarks included the choroid plexus, veins, mammillary bodies, infundibular recess, and basilar artery. The thinned-out third ventricle floor, which dissects appropriately, is quickly replaceable. Standard neuroendoscopic equipment including irrigation is used. Bleeding scenarios are also incorporated. A total of 16 neurosurgical trainees (Postgraduate Years 1-6) and 9 pediatric and adult neurosurgeons tested the simulator. All participants filled out questionnaires (5-point Likert-type items) to rate the simulator for face and content validity.

RESULTS

The simulator is portable, robust, and sets up in minutes. More than 95% of participants agreed or strongly agreed that the simulator's anatomical features, tissue properties, and bleeding scenarios were a realistic representation of that seen during an ETV. Participants stated that the simulator helped develop the required hand-eye coordination and camera skills, and the training exercise was valuable.

CONCLUSIONS

A low-cost, reusable, silicone-based ETV simulator realistically represents the surgical procedure to trainees and neurosurgeons. It can help them develop the technical and cognitive skills for ETV including dealing with complications.

Ventricular endoscopy in the pediatric population: review of indications

INTRODUCTION

Neuroendoscopy has greatly impacted pediatric neurosurgery over the past few decades. Improved optics and microsurgical tools have allowed neuroendoscopes to be used for a multitude of neurosurgical procedures.

DISCUSSION

In this review article, we present the breadth of intraventricular neuroendoscopic procedures for the treatment of conditions ranging from hydrocephalus and brain tumors to congenital cysts and other pathologies. We critically discuss treatment indications and reported success rates for neuroendoscopic procedures. We also present novel approaches, technical nuances, and variations from recently published literature and as practiced in the authors' institution.

The use of simulation in neurosurgical education and training

Object

There is increasing evidence that simulation provides high-quality, time-effective training in an era of resident duty-hour restrictions. Simulation may also permit trainees to acquire key skills in a safe environment, important in a specialty such as neurosurgery, where technical error can result in devastating consequences. The authors systematically reviewed the application of simulation within neurosurgical training and explored the state of the art in simulation within this specialty. To their knowledge this is the first systematic review published on this topic to date.

Methods

The authors searched the Ovid MEDLINE, Embase, and PsycINFO databases and identified 4101 articles; 195 abstracts were screened by 2 authors for inclusion. The authors reviewed data on study population, study design and setting, outcome measures, key findings, and limitations.

Results

Twenty-eight articles formed the basis of this systematic review. Several different simulators are at the neurosurgeon's disposal, including those for ventriculostomy, neuroendoscopic procedures, and spinal surgery, with evidence for improved performance in a range of procedures. Feedback from participants has generally been favorable. However, study quality was found to be poor overall, with many studies hampered by nonrandomized design, presenting normal rather than abnormal anatomy, lack of control groups and long-term follow-up, poor study reporting, lack of evidence of improved simulator performance translating into clinical benefit, and poor reliability and validity evidence. The mean Medical Education Research Study Quality Instrument score of included studies was 9.21 ± 1.95 (± SD) out of a possible score of 18.

Conclusions

The authors demonstrate qualitative and quantitative benefits of a range of neurosurgical simulators but find significant shortfalls in methodology and design. Future studies should seek to improve study design and reporting, and provide long-term follow-up data on simulated and ideally patient outcomes.

A Perfusion-based Human Cadaveric Model for Management of Carotid Artery Injury during Endoscopic Endonasal Skull Base Surgery

Objective To create and develop a reproducible and realistic training environment to prepare residents and trainees for arterial catastrophes during endoscopic endonasal surgery. Design An artificial blood substitute was perfused at systolic blood pressures in eight fresh human cadavers to mimic intraoperative scenarios. Setting The USC Keck School of Medicine Fresh Tissue Dissection Laboratory was used as the training site. Participants Trainees were USC neurosurgery residents and junior faculty. Main Outcome A 5-point questionnaire was used to assess pre- and posttraining confidence scores. Results High-pressure extravasation at normal arterial blood pressure mimicked real intraoperative internal carotid artery (ICA) injury. Residents developed psychomotor skills required to achieve hemostasis using suction, cottonoids, and muscle grafts. Questionnaire responses from all trainees reported a realistic experience enhanced by the addition of the perfusion model. Conclusions The addition of an arterial perfusion system to fresh tissue cadavers is among the most realistic training models available. This enables the simulation of rare intraoperative scenarios such as ICA injury. Strategies for rapid hemostasis and implementation of techniques including endoscope manipulation, suction, and packing can all be rehearsed via this novel paradigm.

Evaluation of an intraoperative ultrasound training model based on a cadaveric sheep brain

Background:

The present study evaluates the effectiveness of an ultrasound (US) practice course based on a sheep brain cadaver. Neurosurgical education is considerably restrained following patient safety objections and work time restrictions. It is therefore of vital importance to offer residents an opportunity to practice certain US techniques in a controlled environment without ethical or legal restrictions. We developed an US training model based on a sheep brain cadaver in order to demonstrate the feasibility of such a model, facilitate crucial anatomic knowledge, and demonstrate a learning curve from it.

Methods:

Over the course of 2 months from December 2012-January 2013, a total of 13 residents took part in a three part training session, each consisting of 20-30 min of individual US-training and performance evaluation based on a biological phantom. The first cadaver was a physiologic sheep brain. After initial familiarization with the US, the residents performed an US on a second cadaveric brain and tried to find a 0.5 cm big (in diameter) echogenic structure. In a third brain they were asked to identify a cyst (Fogarty catheter filled with water).

Results:

Thirteen neurosurgical residents participated in the study. After the first training session, the learning curve improved significantly in the second and the third session. The ability to actuate the US device, the time needed to display crucial anatomic landmarks, and to locate the two different artificial masses increased, and respectively decreased remarkably by up to 80%.

Conclusion:

After 2 months and three training sessions, the handling of the US from the residents was excellent in the operating room. The accuracy and the dexterity in use of the US improved significantly. The participants found the model to be realistic and agreed on the need for further promotion of such courses.

Design of a synthetic simulator for pediatric lumbar spine pathologies

OBJECT

Simulation has become an important tool in neurosurgical education as part of the complex process of improving residents' technical expertise while preserving patient safety. Although different simulators have already been designed for a variety of neurosurgical procedures, spine simulators are still in their infancy and, at present, there is no available simulator for lumbar spine pathologies in pediatric neurosurgery. In this paper the authors describe the peculiarities and challenges involved in developing a synthetic simulator for pediatric lumbar spine pathologies, including tethered spinal cord syndrome and open neural tube defects.

METHODS

The Department of Neurosurgery of the University of Illinois at Peoria, in a joint program with the Mechanical Engineering Department of Bradley University, designed and developed a general synthetic model for simulating pediatric neurosurgical interventions on the lumbar spine. The model was designed to be composed of several sequential layers, so that each layer might closely mimic the tensile properties of the natural tissues under simulation. Additionally, a system for pressure monitoring was developed to enable precise measurements of the degree of manipulation of the spinal cord.

RESULTS

The designed prototype successfully simulated several scenarios commonly found in pediatric neurosurgery, such as tethered spinal cord, retethered spinal cord, and fatty terminal filum, as well as meningocele, myelomeningocele, and lipomyelomeningocele. Additionally, the formulated grading system was able to account for several variables involved in the qualitative evaluation of the technical performance during the training sessions and, in association with an expert qualitative analysis of the recorded sessions, proved to be a useful feedback tool for the trainees.

CONCLUSIONS

Designing and building a synthetic simulator for pediatric lumbar spine pathologies poses a wide variety of unique challenges. According to the authors' experience, a modular system composed of separable layers that can be independently replaced significantly enhances the applicability of such a model, enabling its individualization to distinctive but interrelated pathologies. Moreover, the design of a system for pressure monitoring (as well as a general score that may be able to account for the overall technical quality of the trainee's performance) may further enhance the educational applications of a simulator of this kind so that it can be further incorporated into the neurosurgical residency curriculum for training and evaluation purposes.

Chicken wing training model for endoscopic microsurgery

Objectives To present and validate a chicken wing model for endoscopic endonasal microsurgical skill development. Setting A surgical environment was constructed using a Styrofoam box and measurements from radiological studies. Endoscopic visualization and instrumentation were utilized in a manner to mimic operative setting. Design Five participants were instructed to complete four sequential tasks: (1) opening the skin, (2) exposing the main artery in its neurovascular sheath, (3) opening the neurovascular sheath, and (4) separating the nerve from the artery. Time to completion of each task was recorded. Participants Three junior attendings, one senior resident, and one medical student were recruited internally. Main Outcome Measures Time to perform the surgical tasks measured in seconds. Results The average time of the first training session was 48.8 minutes; by the 10th training session, the average time was 22.4 minutes. The range of improvement was 25.7 minutes to 72.4 minutes. All five participants exhibited statistically significant decrease in time after 10 trials. Kaplan-Meier analysis revealed that an improvement of 50% was achieved by an average of five attempts at the 95% confidence interval. Conclusions The ex vivo chicken wing model is an inexpensive and relatively realistic model to train endoscopic dissection using microsurgical techniques.