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February 2017

2016 IEEE/SICE International Symposium on System Integration (SII).

A Viscoelastic Model of Brain Parenchyma for Haptic Brain Surgery Simulations

Xiaoshuai Chen, Kazuya Sase, Atsushi Konno, and Teppei Tsujita

This paper presents a viscoelastic model of brain parenchyma which is based on the generalized Maxwell model but considers also inertial force. The proposed model is implemented in finite element method (FEM). The viscoelastic behavior of brain parenchyma was confirmed by stress relaxation tests using porcine brain parenchyma. The stress relaxation characteristics were measured at strain 0.1, 0.2 and 0.3. the strains were applied by strain rates of 0.1 (s−1) and 1.0 (s−1). Viscoelastic parameters were identified by solving an optimization problem using experimental data and dynamic simulations. In order to verify the consistency and quality of the experimental data and the dynamic simulation, stress relaxation simulations were performed using the identified parameters.

January 2017

RCS Bulletin.

The impact of complications and errors on surgeons

K Turner, C Johnson, K Thomas, H Bolderston, S McDougall

Do surgeons need support – and, if so, what kind?

November 2016

Journal of Surgical Education.

Current Status of Simulation in Otolaryngology: A Systematic Review

Omar Musbahi, BEng, Abdullatif Aydin, BSc, MBBS, Yasser Al Omran, BSc, MBBS, Christopher James Skilbeck, FRCS (ORL-HNS), MPhil (Cantab), Kamran Ahmed, MBBS, MRCS, PhD

OBJECTIVE: Otolaryngology is a highly technical and demanding specialty and the requirements for surgical trainees to acquire proficiency remains challenging. Simulation has been purported to be an effective tool in assisting with this. The aim of this systematic review is to identify the available otolaryngology simulators, their status of validation, and evaluation the level of evidence behind each training model and thereby establish a level of recommendation.

DESIGN: PubMed, ERIC, and Google Scholar databases were searched for articles that described otolaryngology simulators or training models between 1980 and April 2016. Any validation studies for simulators were also retrieved. Titles and abstracts were screened for relevance using the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. Level of evidence (LoE) and Level of recommendation (LoR) was awarded to each study and model, respectively.

RESULTS: A total of 70 studies were identified describing 64 simulators. Out of these, at least 54 simulators had 1 validation study. Simulators for the ear and temporal bone surgery were the most common (n = 32), followed by laryngeal and throat (n = 20) and endoscopic sinus surgery (n = 12). Face validity was evaluated by 29 studies, 20 attempted to show construct, 20 assessed content, 20 transfer, and only 2 assessed concurrent validity. Of the validation assessments, 2 were classified as Level 1b, 10 Level 2a, and 48 Level 2b. No simulators received the highest LoR, but 8 simulators received a LoR of 2.

CONCLUSIONS: Despite the lack of evidence in outcome studies and limited number of high-validity otolaryngology simulators, the role of simulation continues to grow across surgical specialties Hence, it is imperative that the simulators are of high validity and construct for trainees to practice and rehearse surgical skills to develop confidence.

KEYWORDS: otolaryngology; ENT; simulation; training; validation; systematic review



The 4th International Conference on Robotics and Mechatronics. Link.

Phenomenological Contact Model Characterization and Haptic Simulation of an Endoscopic Sinus and Skull Base Surgery Virtual System

Soroush Sadeghnejad, Mojtaba Esfandiari, Farzam Farahmand, G.R. Vossoughi

During the endoscopic sinus and skull base training surgeries, the haptic perception of tool-tissue interaction and even transitions and ruptures in the tissues are fundamental which should be taken into account in a robotic control scheme. However, this problem is extremely complex given the nature and the variety of tissues involved in an ESS procedures. In this article, ex-vivo indentation and relaxation experiments associated with an offline model estimation of the interaction between tissues and a surgical tool are presented. The estimated parameters of the modified Kelvin-Voigt model are then used to provide a realistic tool-tissue interaction dynamic model. Finally, the principle of a virtual reality simulation scheme that would allow better haptic discrimination of tool-tissue interaction is proposed and illustrated.



Journal of Clinical Neuroscience. 

Utilizing virtual and augmented reality for educational and clinical enhancements in neurosurgery

Panayiotis E. Pelargos, Daniel T. Nagasawa, Carlito Lagman, Stephen Tenn, Joanna V. Demos, Seung J. Lee, Timothy T. Bui, Natalie E. Barnette, Nikhilesh S. Bhatt, Nolan Ung, Ausaf Bari, Neil A. Martin, Isaac Yang

Neurosurgery has undergone a technological revolution over the past several decades, from trephination to image-guided navigation. Advancements in virtual reality (VR) and augmented reality (AR) represent some of the newest modalities being integrated into neurosurgical practice and resident education. In this review, we present a historical perspective of the development of VR and AR technologies, analyze its current uses, and discuss its emerging applications in the field of neurosurgery.

KEYWORDS: Augmented reality; Education; History; Innovations; Neurosurgery; Virtual reality

October 2016

Current Otorhinolaryngology Reports.

The Use of Computerised Simulation for the Training of Endoscopic Sinus Surgery

A. Simon Carney, Nuwan Dharmawardana, Karen Reynolds

PURPOSE: This review summarises the progress made in the development of computer–based simulation for the training of endoscopic sinus surgery. What are the current limitations of available simulators? What does the future hold for such technology?

RECENT FINDINGS:  Advances in three-dimensional image processing and highly customisable programming platforms have meant that realistic, haptic feedback enabled, computerised virtual reality simulators are now available. Several simulators have now been validated using scientific methodology. Fidelity of these simulators largely varies from high to low and evidence is lacking as to what the level of fidelity plays in the overall usefulness of a simulator. The range of surgical techniques able to be performed remains limited and introducing anatomical variables remains a challenge within this field.

SUMMARY: Whilst computerised simulation for training endoscopic sinus surgery has made major advances in the last decade, it still has significant limitations. Improvements in haptic removal of sinus tissue, introduction of variable anatomy and bleeding simulation may allow greater acceptance of this technology in the future.

KEYWORDS: Computer simulation; Endoscopic sinus surgery; Nasendoscopy; HapticsValidation; Virtual reality

September 2016


Simulator-Based Angiography and Endovascular Neurosurgery Curriculum: A Longitudinal Evaluation of Performance Following Simulator-Based Angiography Training

J. Scott Pannell, David R. Santiago-Dieppa, Arvin R. Wali, Brian R. Hirshman, Jeffrey A. Steinberg, Vincent J. Cheung, David Oveisi, Jon Hallstrom, Alexander A. Khalessi

This study establishes performance metrics for angiography and neuroendovascular surgery procedures based on longitudinal improvement in individual trainees with differing levels of training and experience.

Over the course of 30 days, five trainees performed 10 diagnostic angiograms, coiled 10 carotid terminus aneurysms in the setting of subarachnoid hemorrhage, and performed 10 left middle cerebral artery embolectomies on a Simbionix Angio Mentor™ simulator. All procedures were nonconsecutive. Total procedure time, fluoroscopy time, contrast dose, heart rate, blood pressures, medications administered, packing densities, the number of coils used, and the number of stent-retriever passes were recorded. Image quality was rated, and the absolute value of technically unsafe events was recorded. The trainees’ device selection, macrovascular access, microvascular access, clinical management, and the overall performance of the trainee was rated during each procedure based on a traditional Likert scale score of 1=fail, 2=poor, 3=satisfactory, 4=good, and 5=excellent. These ordinal values correspond with published assessment scales on surgical technique.

After performing five diagnostic angiograms and five embolectomies, all participants demonstrated marked decreases in procedure time, fluoroscopy doses, contrast doses, and adverse technical events; marked improvements in image quality, device selection, access scores, and overall technical performance were additionally observed (p < 0.05). Similarly, trainees demonstrated marked improvement in technical performance and clinical management after five coiling procedures (p < 0.05). However, trainees with less prior experience deploying coils continued to experience intra-procedural ruptures up to the eighth embolization procedure; this observation likely corresponded with less tactile procedural experience to an exertion of greater force than appropriate for coil placement.

Trainees across all levels of training and prior experience demonstrated a significant performance improvement after completion of our simulator curriculum consisting of five diagnostic angiograms, five embolectomy cases, and 10 aneurysm coil embolizations.

August 2016

Acta Neurochir.

Residency program trainee-satisfaction correlate with results of the European board examination in neurosurgery

Martin N. Stienen, David Netuka, Andreas K. Demetriades, Florian Ringel, Oliver P. Gautschi, Jens Gempt, Dominique Kuhlen, Karl Schaller

INTRODUCTION: Substantial country differences in neurosurgical training throughout Europe have recently been described, ranging from subjective rating of training quality to objective working hours per week. The aim of this study was to analyse whether these differences translate into the results of the written and oral part of the European Board Examination in Neurological Surgery (EBE-NS). 

METHODS: Country-specific composite scores for satisfaction with quality of theoretical and practical training, as well as working hours per week, were obtained from an electronic survey distributed among European neurosurgical residents between June 2014 and March 2015. These were related to anonymous country-specific results of the EBE-NS between 2009 and 2016, using uni- and multivariate linear regression analysis. 

RESULTS: A total of n = 1025 written and n = 63 oral examination results were included. There was a significant linear relationship between the country-specific EBE-NS result in the written part and the country-specific composite score for satisfaction with quality of theoretical training [adjusted regression coefficient (RC) −3.80, 95 % confidence interval (CI) -5.43–7 -2.17, p < 0.001], but not with practical training or working time. For the oral part, there was a linear relationship between the country-specific EBE-NS result and the country-specific composite score for satisfaction with quality of practical training (RC 9.47, 95 % CI 1.47–17.47, p = 0.021), however neither with satisfaction with quality of theoretical training nor with working time. 

CONCLUSION: With every one-step improvement on the country-specific satisfaction score for theoretical training, the score in the EBE-NS Part 1 increased by 3.8 %. With every one-step improvement on the country-specific satisfaction score for practical training, the score in the EBE-NS Part 2 increased by 9.47 %. Improving training conditions is likely to have a direct positive influence on the knowledge level of trainees, as measured by the EBE-NS. The effect of the actual working time on the theoretical and practical knowledge of neurosurgical trainees appears to be insignificant.

KEYWORDS: Residency; Training; Country difference; Board examination; Residency; Quality; EANS; European Board Examination; Neurosurgery education; Trainee satisfaction



World Neurosurgery.

A low-cost passive navigation training system for image-guided spinal intervention

Lorias Espinoza Daniel, PhD, Vicente González Carranza, MD, Fernando Chico Ponce de León, MD, Fernando Pérez Escamirosa, PhD, Arturo Minor Martinez, PhD

BACKGROUND: Navigation technology is used for training in various medical specialties, not least image-guided spinal interventions. Navigation practice is an important educational component that allows residents to understand how surgical instruments interact with complex anatomy and to learn basic surgical skills such as the tri-dimensional mental interpretation of bi-dimensional data. However, inexpensive surgical simulators for spinal surgery are lacking. We therefore designed a low-cost spinal surgery simulator (Spine MovDigSys 01) to allow 3D navigation using 2D images without altering or limiting the surgeon’s natural movement.

METHODS: A training system was developed using an anatomical lumbar model and two webcams to passively digitize surgical instruments under MATLAB software control. A proof-of-concept recognition task (vertebral body cannulation) and a pilot test of the system with 12 neuro- and orthopedic surgeons were performed to obtain feedback on the system. Position, orientation, and kinematic variables were determined and the lateral, posteroanterior, and anteroposterior (AP) views obtained.

RESULTS: The system was tested using a proof-of-concept experimental task. Operator metrics including time of execution (t), intracorporeal length (d), insertion angle (α  ), average speed (View the MathML source), and acceleration (a) were accurately obtained. These metrics were converted into assessment metrics such as smoothness of operation and linearity of insertion. Results from initial testing are shown and the system advantages and disadvantages described.

CONCLUSIONS: This low-cost spinal surgery training system digitized the position and orientation of the instruments and allowed image-guided navigation, the generation of metrics, and graphic recording of the instrumental route. Spine MovDigSys 01 is useful for development of basic, non-innate skills and allows the novice apprentice to quickly and economically move beyond the basics.

KEYWORDS: training in neurosurgery; spine simulator; metric-based teaching; spine trainer simulator

May 2016

Medicine Meets Virtual Reality 22.

An Examination of Metrics for a Simulated Ventriculostomy Part-Task

Ryan Armstrong ; Dayna Noltie ; Roy Eagleson ; Sandrine De Ribaupierre

As one of the most commonly performed neurosurgical procedures, ventriculostomy training simulators are becoming increasingly familiar features in research institutes and teaching facilities. Despite their widespread implementations and adoption, simulators to date have not fully explored the landscape of performance metrics that reflect surgical proficiency. They opt instead for measures that are qualitative or simple to compute and conceptualize. In this paper, we examine and compare the use of various metrics to characterize the performance of users on simulated part-task ventriculostomy scenarios derived from patient data. As an initial study, we examine how our metrics relate to expert classification of scenario difficulty as well as measures of anatomical variation.

KEYWORDS: surgical simulation; ventriculostomy; human performance; performance metrics




A Force-sensing Bipolar Forceps to Quantify Tool-tissue Interaction Forces in Microsurgery

Kourosh Zareinia ; Yaser Maddahi ; Liu Shi Gan ; Ahmad Ghasemoonia ; Sanju Lama ; Taku Sugiyama ; Fang Wei Yang ; Garnette Sutherland

The ability to exert an appropriate amount of force on brain tissue during surgery is an important component of instrument handling. It allows surgeons to achieve the surgical objective effectively while maintaining a safe level of force in tool-tissue interaction. At the present time, this knowledge and hence skill is acquired through experience, and qualitatively conveyed from an expert surgeon to trainees. These forces can be assessed quantitatively by retrofitting surgical tools with sensors, thus providing a mechanism for improved performance and safety of surgery and enhanced surgical training. This paper presents the development of a force-sensing bipolar forceps, with installation of a sensory system, that is able to measure and record interaction forces between the forceps tips and brain tissue in real-time. This research is an extension of a previous research where a bipolar forceps was instrumented to measure dissection and coagulation forces applied in a single direction. Here, a planar forceps with two sets of strain gauges in two orthogonal directions was developed to enable measuring the forces with a higher accuracy. Implementation of two strain gauges allowed compensation of strain values due to deformations of the forceps in other directions (axial stiffening) and provided more accurate forces during microsurgery. An experienced neurosurgeon performed five neurosurgical tasks using the axial setup, and repeated the same tasks using the planar device. The experiments were performed on cadaveric brains. Both setups were shown to be capable of measuring real-time interaction forces. Comparing the two setups, under the same experimental condition, indicated that the peak and mean forces quantified by planar forceps were at least 7% and 10% less than those of axial tool, respectively, therefore utilizing readings of all strain gauges in planar forceps provide more accurate values of both peak and mean forces than axial forceps. Cross correlation analys- s between the two force signals obtained, one from each cadaveric practice, showed a high similarity between the two force signals.

KEYWORDS: Bipolar forceps; cross correlation; neurosurgery; sensors; surgical training; tool-tissue interaction forces



Neurology India.

Simulation in neurosurgery: Past, present, and future

Ashish Suri, Devi Prasad Patra, Rajesh Kumar Meena

Neurosurgery is one of the most technically demanding medical professions that warrants a high level of expertise. In the present context of competitive medical practice, high societal expectations regarding quality of patient care and medicolegal and financial constraints, there are fewer opportunities for a trainee to achieve competency in standard neurosurgical, microsurgical, and operative techniques. Practice on simulation models like cadavers has been a trend since antiquity; however, recent development of newer models with their strategic modifications has given simulation education a new dimension. It has allowed trainees to acquire and improve surgical skills and knowledge in specifically fabricated and controlled settings with no risk to real patients. Simulation also offers the opportunity for deliberate practice and repetition unlimited number of times so that psychomotor skills can be automated. There is ever-growing evidence showing the positive impact of simulation on resident training in various areas of health care. Advances in computer technology and imaging, development of sophisticated virtual reality simulators with haptic feedback and the recent addition of three-dimensional printing technology, have opened a wide arena for the development of high-fidelity patient-specific models to complement current neurosurgical training. Simulation training in neurosurgery in India is still elementary since its inception at the All India Institute of Medical Sciences, New Delhi. A structured modular training program has been developed which is yet to be implemented at a multi-institutional level. Stringent efforts are needed to establish a uniform resident training curriculum where simulators can be used to complement current neurosurgical training.

KEYWORDS: Curriculum; neurosurgery; simulation; skills training; virtual reality

April 2016

Knee Surgery, Sports Traumatology, Arthroscopy.

Validation of the updated ArthroS simulator: face and construct validity of a passive haptic virtual reality simulator with novel performance metrics

Patrick Garfjeld Roberts, Paul Guyver, Mathew Baldwin, Kash Akhtar, Abtin Alvand, Andrew J. Price, Jonathan L. Rees

PURPOSE: To assess the construct and face validity of ArthroS, a passive haptic VR simulator. A secondary aim was to evaluate the novel performance metrics produced by this simulator.

METHODS: Two groups of 30 participants, each divided into novice, intermediate or expert based on arthroscopic experience, completed three separate tasks on either the knee or shoulder module of the simulator. Performance was recorded using 12 automatically generated performance metrics and video footage of the arthroscopic procedures. The videos were blindly assessed using a validated global rating scale (GRS). Participants completed a survey about the simulator’s realism and training utility.

RESULTS: This new simulator demonstrated construct validity of its tasks when evaluated against a GRS (p ≤ 0.003 in all cases). Regarding it’s automatically generated performance metrics, established outputs such as time taken (p ≤ 0.001) and instrument path length (p ≤ 0.007) also demonstrated good construct validity. However, two-thirds of the proposed ‘novel metrics’ the simulator reports could not distinguish participants based on arthroscopic experience. Face validity assessment rated the simulator as a realistic and useful tool for trainees, but the passive haptic feedback (a key feature of this simulator) is rated as less realistic.

CONCLUSION: The ArthroS simulator has good task construct validity based on established objective outputs, but some of the novel performance metrics could not distinguish between surgical experience. The passive haptic feedback of the simulator also needs improvement. If simulators could offer automated and validated performance feedback, this would facilitate improvements in the delivery of training by allowing trainees to practise and self-assess.

KEYWORDS: Simulation; Arthroscopy; Training; Virtual reality


Arch Med Sci. Link

Augmented reality in neurosurgery

Raniel Tagaytayan, Arpad Kelemen, Cecilia Sik-Lanyi

Neurosurgery is a medical specialty that relies heavily on imaging. The use of computed tomography and magnetic resonance images during preoperative planning and intraoperative surgical navigation is vital to the success of the surgery and positive patient outcome. Augmented reality application in neurosurgery has the potential to revolutionize and change the way neurosurgeons plan and perform surgical procedures in the future. Augmented reality technology is currently commercially available for neurosurgery for simulation and training. However, the use of augmented reality in the clinical setting is still in its infancy. Researchers are now testing augmented reality system prototypes to determine and address the barriers and limitations of the technology before it can be widely accepted and used in the clinical setting.

KEYWORDS: augmented reality; neurosurgery; immersive environment

March 2016

Child's Nervous System.

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

Guodao Wen, ZiXiang Cong, KaiDong Liu, Chao Tang, Chunyu Zhong, Liwen Li, XuJie Dai, Chiyuan Ma 

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.

KEYWORDS: The 3D printed simulator; Endoscopic endonasal transsphenoidal surgery; Three basic operational skills; Drilling Curetting; Aspirating


Journal of Medical Systems.

A Review of Simulators with Haptic Devices for Medical Training

Escobar-Castillejos D, Noguez J, Neri L, Magana A, Benes B

Medical procedures often involve the use of the tactile sense to manipulate organs or tissues by using special tools. Doctors require extensive preparation in order to perform them successfully; for example, research shows that a minimum of 750 operations are needed to acquire sufficient experience to perform medical procedures correctly. Haptic devices have become an important training alternative and they have been considered to improve medical training because they let users interact with virtual environments by adding the sense of touch to the simulation. Previous articles in the field state that haptic devices enhance the learning of surgeons compared to current training environments used in medical schools (corpses, animals, or synthetic skin and organs). Consequently, virtual environments use haptic devices to improve realism. The goal of this paper is to provide a state of the art review of recent medical simulators that use haptic devices. In particular we focus on stitching, palpation, dental procedures, endoscopy, laparoscopy, and orthopaedics. These simulators are reviewed and compared from the viewpoint of used technology, the number of degrees of freedom, degrees of force feedback, perceived realism, immersion, and feedback provided to the user. In the conclusion, several observations per area and suggestions for future work are provided.

KEYWORDS: 3D simulators; E-learning; Haptic devices; Medical training; Training


World Neurosurgery.

Using 3D printing to create personalized brain models for neurosurgical training and preoperative planning

Caitlin C. Ploch, B.Sc, Chris S.S.A. Mansi, MRCS, Jayaratnam Jayamohan, FRCS, Ellen Kuhl, Dr.-Ing 

Three-dimensional (3D) printing holds promise for a wide variety of biomedical applications, from surgical planning, practicing, and teaching to creating implantable devices. The growth of this cheap and easy additive manufacturing technology in orthopaedic, plastic, and vascular surgery has been explosive; however, its potential in the field of neurosurgery remains underexplored. A major limitation is that current technologies are unable to directly print ultrasoft materials like human brain tissue. In this technical note, the authors present a new technology to create deformable, personalized models of the human brain. The method combines 3D printing, molding, and casting to create a physiologically, anatomically, and tactilely realistic model based on magnetic resonance images. Created from soft gelatin, the model is easy to produce, cost-efficient, durable, and orders of magnitude softer than conventionally printed 3D models. The personalized brain model cost $50, and its fabrication took 24 hours. In mechanical tests, the model stiffness (E=25.29 ± 2.68kPa) was five orders of magnitude softer than common 3D printed materials, and less than an order of magnitude stiffer than mammalian brain tissue (E=2.64 ± 0.40kPa). In a multicenter surgical survey, model size (100.00%), visual appearance (83.33%), and surgical anatomy (81.25%) were perceived as very realistic. The model was perceived as very useful for patient illustration (85.00%), teaching (94.44%), learning (100.00%), surgical training (95.00%), and preoperative planning (95.00%). With minor refinements, personalized, deformable brain models created via 3D printing will improve surgical training and preoperative planning with the ultimate goal to provide accurate, customized, high precision treatment.

KEYWORDS: Neurosurgery; Training; Clinical Skills; Simulation; 3D Printing

January 2016


Prospective error recording in surgery : an analysis of 1108 elective neurosurgical cases

Stone, Scellig M.D.; Bernstein, Mark M.D., M.H.Sc., F.R.C.S.C.

OBJECTIVE: Surgical error is common and contributes to complications for patients, necessitating detailed prospective collection and analysis of error data that emphasizes prevention.

METHODS: One neurosurgeon prospectively recorded errors and complications for consecutive patients undergoing elective neurosurgical procedures. Each error was scored for type, severity, preventability, and consequence.

RESULTS: Between May 2000 and August 2006, 1108 elective cases were studied, comprising 76.1% cranial, 22.7% spinal, and 1.2% other procedures. There were 2684 errors in 87.1% of cases. The most common errors were technical (27.8%), contamination (25.3%), equipment failure or missing equipment (18.2%), or related to delay (12.5%). Of the errors, 22.6% were considered major and 77.4% were minor, with 2.7% of errors substantially impacting the clinical course of the patient. Of all errors, 78.5% were deemed preventable. Of the complications, 16.7% were related to errors, of which 80.6% were major errors. Of the error-related complications, 74.2% were declared preventable. A propensity for error was identified with cranial procedures and patients with higher American Society of Anesthesiologists scores (P < 0.01).

CONCLUSION: Surgical errors are common, often preventable, and frequently lead to clinical impact. In addition, the type of procedure and characteristics of the patient are important factors to consider when addressing surgical error. For individual surgeons to maintain quality control and contribute to the safety of the health care system, they must track and analyze errors to ensure that systems may be developed to prevent their occurrence.


NMR in Biomedicine.

Neural correlates of motor imagery for elite archers

Yongmin Chang, Jae-Jun Lee, Jee-Hye Seo, Hui-Jin Song, Yang-Tae Kim, Hui Joong Lee, Hye Jung Kim, Jongmin Lee, Woojong Kim, Minjung Woo and Jin Gu Kim

Motor imagery is a mental rehearsal of simple or complex motor acts without overt body movement. It has been proposed that the association between performance and the mental rehearsal period that precedes the voluntary movement is an important point of difference between highly trained athletes and beginners. We compared the activation maps of elite archers and nonarchers during mental rehearsal of archery to test whether the neural correlates of elite archers were more focused and efficiently organised than those of nonarchers. Brain activation was measured using functional MRI in 18 right-handed elite archers and 18 right-handed nonarchers. During the active functional MRI imagery task, the participants were instructed to mentally rehearse their archery shooting from a first-person perspective. The active imagery condition was tested against the nonmotor imagery task as a control condition. The results showed that the premotor and supplementary motor areas, and the inferior frontal region, basal ganglia and cerebellum, were active in nonarchers, whereas elite archers showed activation primarily in the supplementary motor areas. In particular, our result of higher cerebellar activity in nonarchers indicates the increased participation of the cerebellum in nonarchers when learning an unfamiliar archery task. Therefore, the difference in cerebellar activation between archers and nonarchers provides evidence of the expertise effect in the mental rehearsal of archery. In conclusion, the relative economy in the cortical processes of elite archers could contribute to greater consistency in performing the specific challenge in which they are highly practised.

KEYWORDS: motor imagery; fMRI; archery; expertise effects; brain


Journal of Neurosurgery.

Attrition rates in neurosurgery residency: analysis of 1361 consecutive residents matched from 1990 to 1999

Gabrielle Lynch, Karina Nieto, BA, Saumya Puthenveettil, MS, Marleen Reyes, BA, Michael Jureller, BS, Jason H. Huang, MD, M. Sean Grady, MD, Odette A. Harris, MD, MPH, Aruna Ganju, MD, Isabelle M. Germano, MD, Julie G. Pilitsis, MD, PhD, Susan C. Pannullo, MD, Deborah L. Benzil, MD, Aviva Abosch, MD, PhD, Sarah J. Fouke, MD, and Uzma Samadani, MD, PhD

OBJECT: The objective of this study is to determine neurosurgery residency attrition rates by sex of matched applicant and by type and rank of medical school attended.

METHODS: The study follows a cohort of 1361 individuals who matched into a neurosurgery residency program through the SF Match Fellowship and Residency Matching Service from 1990 to 1999. The main outcome measure was achievement of board certification as documented in the American Board of Neurological Surgery Directory of Diplomats. A secondary outcome measure was documentation of practicing medicine as verified by the American Medical Association DoctorFinder and National Provider Identifier websites. Overall, 10.7% (n = 146) of these individuals were women. Twenty percent (n = 266) graduated from a top 10 medical school (24% of women [35/146] and 19% of men [232/1215], p = 0.19). Forty-five percent (n = 618) were graduates of a public medical school, 50% (n = 680) of a private medical school, and 5% (n = 63) of an international medical school. At the end of the study, 0.2% of subjects (n = 3) were deceased and 0.3% (n = 4) were lost to follow-up.

RESULTS: The total residency completion rate was 86.0% (n = 1171) overall, with 76.0% (n = 111/146) of women and 87.2% (n = 1059/1215) of men completing residency. Board certification was obtained by 79.4% (n = 1081) of all individuals matching into residency between 1990 and 1999. Overall, 63.0% (92/146) of women and 81.3% (989/1215) of men were board certified. Women were found to be significantly more at risk (p < 0.005) of not completing residency or becoming board certified than men. Public medical school alumni had significantly higher board certification rates than private and international alumni (82.2% for public [508/618]; 77.1% for private [524/680]; 77.8% for international [49/63]; p < 0.05). There was no significant difference in attrition for graduates of top 10–ranked institutions versus other institutions. There was no difference in number of years to achieve neurosurgical board certification for men versus women.

CONCLUSIONS: Overall, neurosurgery training attrition rates are low. Women have had greater attrition than men during and after neurosurgery residency training. International and private medical school alumni had higher attrition than public medical school alumni.

KEYWORDS: attrition, board certification, sex, neurosurgery residency


World Neurosurgery.

Simulation in Neurosurgery—A Brief Review and Commentary

Mary In-Ping Huang Cobb, Jeffrey M. Taekman, Ali R. Zomorodi, L. Fernando Gonzalez, Dennis A. Turner

Neurosurgery is one of the most technically demanding and liable of all medical professionals. More than 75% of neurosurgical errors are deemed as preventable and technical in nature. Yet in a specialty that requires such high level of technical expertise, with large consequences for error, there are even fewer opportunities for residents in training to practice on the most complicated cases. Although there is no replacement for actual experiences in the operating room, interpersonal mentorship, coaching, and training, there is room to supplement residency education through simulation. Here we review the evidence to support surgical simulation, describe the strengths and weaknesses of existing technologies in direct neurosurgery specific and indirect simulation applications, and advocate for the development of more neurosurgery-specific applications using emerging kinetic technologies.

KEYWORDS: Haptic feedback, Neurostimulation, Neurosurgery simulation, Residency training, Technical skills education


World Neurosurgery.

Neurosurgical Skills Assessment: Measuring Technical Proficiency in Neurosurgery Residents through Intraoperative Video Evaluations

Christopher A. Sarkiss, M.D., Steven Philemond, B.A., James Lee, M.D., Stanislaw Sobotka, Ph.D., Terrell D. Holloway, B.S., Maximillian Moore, Anthony B. Costa, Ph.D., Errol L. Gordon, M.D., Joshua B. Bederson, M.D.

BACKGROUND: Although technical skills are fundamental in neurosurgery, there is little agreement on how to describe, measure, or compare skills among surgeons. The primary goal of this study was to develop a quantitative grading scale for technical surgical performance that distinguishes operator skill when graded by domain experts (residents, attendings, and non-surgeons). Scores provided by raters should be highly reliable with respect to scores from other observers.

METHODS: Neurosurgery residents were fitted with a head-mounted video camera while performing craniotomies under attending supervision. Seven videos, one from each PGY level (1-7), were anonymized and scored by 16 attendings, 8 residents, and 7 non-surgeons using a grading scale. Seven skills were graded; these were incision, efficiency of instrument use, cauterization, tissue handling, drilling/craniotomy, confidence, and training level.

RESULTS: A strong correlation was found between skills score and PGY year (p< .001, ANOVA). Junior residents (PGY 1-3) had significantly lower scores than senior residents (PGY 4-7, p< .001, t-test). Significant variation among junior residents was observed, while senior residents’ scores were not significantly different from one another. Inter-rater reliability, measured against other observers, was high (r= 0.581 ± 0.245, Spearman) as was assessment of resident training level (r= 0.583 ± 0.278, Spearman). Both variables were strongly correlated (r = 0.90, Pearson). Attendings, residents, and non-surgeons did not score differently (p=0.46, ANOVA).

CONCLUSIONS: Technical skills of neurosurgery residents recorded during craniotomy can be measured with high inter-rater reliability. Surgeons and non-surgeons alike readily distinguish different skill levels. This type of assessment could be used to coach residents, to track performance over time, and potentially to compare skill levels. Developing an objective tool to evaluate surgical performance would be useful in several areas of neurosurgery education.

KEYWORDS: neurosurgery simulation, intraoperative evaluations, surgical skills, video-based resident training


ANZ Journal of Surgery.

Comparing surgical experience with performance on a sinus surgery simulator

Laura E. Diment, Greg S. Ruthenbeck, Nuwan Dharmawardana, A. Simon Carney, Charmaine M. Woods, Eng H. Ooi and Karen J. Reynolds

BACKGROUND: This study evaluates whether surgical experience influences technical competence using the Flinders sinus surgery simulator, a virtual environment designed to teach nasal endoscopic surgical skills.

METHODS: Ten experienced sinus surgeons (five consultants and five registrars) and 14 novices (seven resident medical officers and seven interns/medical students) completed three simulation tasks using haptic controllers. Task 1 required navigation of the sinuses and identification of six anatomical landmarks, Task 2 required removal of unhealthy tissue while preserving healthy tissue and Task 3 entailed backbiting within pre-set lines on the uncinate process and microdebriding tissue between the cuts.

RESULTS: Novices were compared with experts on a range of measures, using Mann–Whitney U-tests. Novices took longer on all tasks (Task 1: 278%, P < 0.005; Task 2: 112%, P < 0.005; Task 3: 72%, P < 0.005). In Task 1, novices' instruments travelled further than experts' (379%, P < 0.005), and provided greater maximum force (12%, P < 0.05). In Tasks 2 and 3 novices performed more cutting movements to remove the tissue (Task 2: 1500%, P < 0.005; Task 3: 72%, P < 0.005). Experts also completed more of Task 3 (66%, P < 0.05).

CONCLUSIONS: The study demonstrated the Flinders sinus simulator's construct validity, differentiating between experts and novices with respect to procedure time, instrument distance travelled and number of cutting motions to complete the task.

KEYWORDS: competency-based education; computer simulation; endoscopy; nasal surgical procedure; user–computer interface


Robomech Journal.

GPU-accelerated surgery simulation for opening a brain fissure

Kazuya Sase, Akira Fukuhara, Teppei Tsujita and Atsushi Konno

In neurosurgery, dissection and retraction are basic techniques for approaching the site of pathology. These techniques are carefully performed in order to avoid damage to nerve tissues or blood vessels. However, novice surgeons cannot train in such techniques using the haptic cues of existing training systems. This paper proposes a real-time simulation scheme for training in dissection and retraction when opening a brain fissure, which is a procedure for creating a working space before treating an affected area. In this procedure, spatulas are commonly used to perform blunt dissection and brain tissue retraction. In this study, the interaction between spatulas and soft tissues is modeled on the basis of a finite element method (FEM). The deformation of soft tissue is calculated according to a corotational FEM by considering geometrical nonlinearity and element inversion. A fracture is represented by removing tetrahedrons using a novel mesh modification algorithm in order to retain the manifold property of a tetrahedral mesh. Moreover, most parts of the FEM are implemented on a graphics processing unit (GPU). This paper focuses on parallel algorithms for matrix assembly and matrix rearrangement related to FEM procedures by considering a sparse-matrix storage format. Finally, two simulations are conducted. A blunt dissection simulation is conducted in real time (less than 20 ms for a time step) using a soft-tissue model having 4807 nodes and 19,600 elements. A brain retraction simulation is conducted using a brain hemisphere model having 8647 nodes and 32,639 elements with force feedback (less than 80 ms for a time step). These results show that the proposed method is effective in simulating dissection and retraction for opening a brain fissure.

KEYWORDS: Surgery simulation; Finite element method; GPGPU

December 2015

Australas Phys Eng Sci Med.

Development of a surgical instrument for measuring forces applied to the ossicles of the middle ear.

Sheedy M, Bergin M, Wylie G, Ross P, Dove R, Bird P.

Surgery of the middle ear is a delicate process that requires the surgeon to manipulate the ossicles, the smallest bones in the body. Excessive force applied to the ossicles can easily be transmitted through to the inner ear which may cause a permanent sensorineural hearing loss. An instrument was required to measure the forces applied to cadaveric temporal bone ossicles with the vision of measuring forces in vivo at a later stage. A feasibility study was conducted to investigate a method of measuring force and torque applied to the ossicles of the middle ear. Information from research papers was gathered to determine the expected amplitudes. The study looked at commercially available transducers as well as constructing an instrument using individual axis transducers coupled together. A prototype surgical instrument was constructed using the ATI industrial automation Nano17 six axis transducer. The Nano17 allows for the measurement of force and torque in the X, Y and Z axis to a resolution of 1/320 N. The use of the Nano17 enabled rapid development of the surgical instrument. It meets the requirements for its use on cadaveric models and has the potential to be a useful data collection tool in vivo.


Ann Biomed Eng.

A Smart Haptic Hand-Held Device for Neurosurgical Microdissection.

Payne CJ, Marcus HJ, Yang GZ.

Microneurosurgery requires dexterity, precision and delicate force application in order to be carried out safely and effectively. Neurosurgeons must apply sufficient force in order to carry out microsurgical procedures effectively but not excessive force such that iatrogenic injury occurs. This paper presents a smart hand-held microsurgical instrument that indicates to the surgeon when a force-threshold has been exceeded by providing vibrotactile feedback. Many existing haptic-feedback systems, particularly master-slave robotic platforms, are large, highly complex, and costly. By comparison, the proposed device is compact, fail-safe and low cost. Two psychophysical user studies were carried out to assess the proposed vibrotactile force-threshold feedback system. A cadaveric pilot study was carried out to evaluate the device in a microdissection task. In all the studies performed, the haptic dissector device has shown to be effective in providing real-time feedback in terms of force application during microsurgical tasks.


Otol Neurotol.

Measuring the forces of middle ear surgery; evaluating a novel force-detection instrument.

Bergin M, Sheedy M, Ross P, Wylie G, Bird P.

HYPOTHESIS: The forces applied to the middle ear structures during surgery are measurable.

BACKGROUND: Surgical forces applied to the middle ear are often cited as a cause of postoperative sensorineural hearing loss; however, no literature exists on how much total force is applied during common middle ear procedures.

METHODS: Using our novel middle ear surgical force sensor, we took measurements from 6 temporal bones of common middle ear manipulations.

RESULTS: Temporal bones of 3 males and 3 females yielded 72 measurements for an average peak applied force and 68 measurements for total applied force across 3 levels of operator experience. Statistically significant differences were seen between different levels of operator and how much force was applied, with senior operators using less force.

CONCLUSION: We show it is possible to measure the applied forces in middle ear surgery and that some of these forces are very large. Larger forces are seen in destructive procedures and in procedures performed by inexperienced operators. This project is an important first step in investigating the association between surgically applied middle ear forces and postoperative sensorineural hearing loss.

October 2015

Child's Nervous System.

Neurosurgical training with simulators: a novel neuroendoscopy model

Sebastián G. Jaimovich, Marcela Bailez, Marcelo Asprea, Roberto Jaimovich

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.

KEYWORDS: Neuroendoscopy, Surgical training, Simulation, Live animal model, Neurosurgical education


VRST '15.

A real time haptic simulator of spine surgeries

Qi Xing, Jim X. Chen, Jihui Li, Ali Moshirfar, Mark M. Theiss, Qi Wei

Spine surgeries are high risk operations which require the surgeons to have ample experiences. For young surgeons, effective and extensive training is critical. This paper presents a real time haptic spine surgical simulator that will be used to train residents, fellows and spine surgeons in a hospital training program. It provides a realistic environment for the trainees to practice spine surgeries and has the advantages of being interactive, low-cost, representative, and repeatable over conventional training approaches. Haptic Phantom offers the users force feedback, differentiating our system from other screen-based training systems. Computational efficiency was achieved by developing advanced graphical rendering methods. The volumetric data was classified into surface voxel cloud and inner voxel cloud by the adjacency graph which stored the relationship among voxels. To speed up the collision detection and real time rendering between the virtual surgical tools and the lumbar model, Octree-based algorithms and GPU technique were applied. To enhance the physical realism, three dimensional lumbar vertebrae models were reconstructed from CT images and associated with non-homogeneous bone density such that the rendered model best represents the spine anatomy and mechanics. We demonstrate system performance by conducting pedicle screw insertion.


J Otolaryngol Head Neck Surg.

Face and content validity of a virtual-reality simulator for myringotomy with tube placement

Huang C, Cheng H, Bureau Y, Agrawal SK, Ladak HM

BACKGROUND: Myringotomy with tube insertion can be challenging for junior Otolaryngology residents as it is one of the first microscopic procedures they encounter. The Western myringotomy simulator was developed to allow trainees to practice microscope positioning, myringotomy, and tube placement. This virtual-reality simulator is viewed in stereoscopic 3D, and a haptic device is used to manipulate the digital ear model and surgical tools.

OBJECTIVE: To assess the face and content validity of the Western myringotomy simulator.

METHODS: The myringotomy simulator was integrated with new modules to allow speculum placement, manipulation of an operative microscope, and insertion of the ventilation tube through a deformable tympanic membrane. A questionnaire was developed in consultation with instructing surgeons. Fourteen face validity questions focused on the anatomy of the ear, simulation of the operative microscope, appearance and movement of the surgical instruments, deformation and cutting of the eardrum, and myringotomy tube insertion. Six content validity questions focused on training potential on surgical tasks such as speculum placement, microscope positioning, tool navigation, ear anatomy, myringotomy creation and tube insertion. A total of 12 participants from the Department of Otolaryngology-Head and Neck Surgery were recruited for the study. Prior to completing the questionnaire, participants were oriented to the simulator and given unlimited time to practice until they were comfortable with all of its aspects.

RESULTS: Responses to 12 of the 14 questions on face validity were predominantly positive. One issue of concern was with contact modeling related to tube insertion into the eardrum, and the second was with the movement of the blade and forceps. The former could be resolved by using a higher resolution digital model for the eardrum to improve contact localization. The latter could be resolved by using a higher fidelity haptic device. With regard to content validity, 64 % of the responses were positive, 21 % were neutral, and 15 % were negative.

CONCLUSIONS: The Western myringotomy simulator appears to have sufficient face and content validity. Further development with automated metrics and skills transference testing is planned.

KEYWORDS: Myringotomy, Education, Simulator, Virtual reality, Face validity


Child's Nervous System.

The role of simulation in neurosurgery

Roberta Rehder, Muhammad Abd-El-Barr, Kristopher Hooten, Peter Weinstock, Joseph R. Madsen, Alan R. Cohen

PURPOSE: In an era of residency duty-hour restrictions, there has been a recent effort to implement simulation-based training methods in neurosurgery teaching institutions. Several surgical simulators have been developed, ranging from physical models to sophisticated virtual reality systems. To date, there is a paucity of information describing the clinical benefits of existing simulators and the assessment strategies to help implement them into neurosurgical curricula. Here, we present a systematic review of the current models of simulation and discuss the state-of-the-art and future directions for simulation in neurosurgery.

METHODS: Retrospective literature review.

RESULTS: Multiple simulators have been developed for neurosurgical training, including those for minimally invasive procedures, vascular, skull base, pediatric, tumor resection, functional neurosurgery, and spine surgery. The pros and cons of existing systems are reviewed.

CONCLUSION: Advances in imaging and computer technology have led to the development of different simulation models to complement traditional surgical training. Sophisticated virtual reality (VR) simulators with haptic feedback and impressive imaging technology have provided novel options for training in neurosurgery. Breakthrough training simulation using 3D printing technology holds promise for future simulation practice, proving high-fidelity patient-specific models to complement residency surgical learning.

KEYWORDS: Simulation, Virtual reality, 3D printing, Residency, Duty hours, Neurosurgery

September 2015

Acta Neurochirurgica.

Training for brain tumour resection: a realistic model with easy accessibility

Marcel A. Kamp, Johannes Knipps, Hans-Jakob Steiger, Marion Rapp, Jan F. Cornelius, Stefanie Folke-Sabel, Michael Sabel

BACKGROUND: Resection of intrinsic and extrinsic brain tumours requires an understanding of sulcal and gyral anatomy, familiarity with tissue consistency and tissue manipulation. As yet, these skills are acquired by observation and supervised manipulation during surgery, thus accepting a potential learning curve at the expense of the patient in a live surgical situation. A brain tumour model could ensure optimised manual skills and understanding of surgical anatomy acquired in an elective and relaxed teaching situation. We report and evaluate a brain tumour model, regarding availability, realistic representation of sulcal and gyral anatomy and tissue consistency.

METHOD: Freshly prepared agar-agar solution with different concentrations was added with highlighter ink and injected into fresh sheep brains.

RESULTS: Hardened agar-agar solution formed masses comparable to malignant brain tumours. Variation of the agar-agar concentration influenced diffusion of agar-agar solution in the adjacent brain tissue. Higher concentrated agar-agar solutions formed sharply delimitated masses mimicking cerebral metastases and lower concentrated agar-agar solutions tended to diffuse into the adjacent cerebral tissue. Adding highlighter ink to the agar-agar solution produced fluorescence after blue light excitation comparable to the 5-ALA induced fluorescence of malignant glioma.

CONCLUSIONS: The described in vitro sheep brain tumour model is simple and realistic, available practically everywhere and cheap. Therefore, it could be useful for young neurosurgical residents to acquire basic neuro-oncological skills, experiencing properties of the cerebral brain texture and its haptic perception and to learn handling of neurosurgical equipment.

KEYWORDS: Metastases, Glioma, Brain tumour, Resident training, Skill


Journal of Neurosurgery.

A physical simulator for endoscopic endonasal drilling techniques: technical note

Bruce L. Tai, PhD, Anthony C. Wang, MD, Jacob R. Joseph, MD, Page I. Wang, MD, Stephen E. Sullivan, MD, Erin L. McKean, MD, MBA, Albert J. Shih, PhD, and Deborah M. Rooney, PhD

ABSTRACT: In this paper, the authors present a physical model developed to teach surgeons the requisite drilling techniques when using an endoscopic endonasal approach (EEA) to the skull base. EEA is increasingly used for treating pathologies of the ventral and ventrolateral cranial base. Endonasal drilling is a unique skill in terms of the instruments used, the long reach required, and the restricted angulation, and gaining competency requires much practice. Based on the successful experience in creating custom simulators, the authors used 3

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