A simulation study to investigate the use of concentric tube robots for epilepsy surgery.

PURPOSE: Patients with pharmacoresistant refractory epilepsy may require epilepsy surgery to prevent future seizure occurrences. Conventional surgery consists of a large craniotomy with straight rigid tools with associated outcomes of morbidity, large tissue resections, and long post-operative recovery times. Concentric tube robots have recently been developed as a promising application to neurosurgery due to their nonlinear form and small diameter. The authors present a concept study to explore the feasibility of performing minimally invasive hemispherotomy with concentric tube robots. METHODS: A model simulation was used to achieve the optimal design and surgical path planning parameters of the concentric tube robot for corpus callosotomy and temporal lobectomy. A single medial burr hole was chosen to access the lateral ventricles for both white matter disconnections. RESULTS: The concentric tube robot was able to accurately reach the designated surgical paths on the corpus callosum and the temporal lobe. CONCLUSION: In a model simulation, the authors demonstrated the feasibility of performing corpus callosotomy and temporal lobectomy using concentric tube robots. Further advancements in the technology may increase the applicability of this technique for epilepsy surgery to better patient outcomes.

An MR-based quantitative intraventricular hemorrhage porcine model for MR-guided focused ultrasound thrombolysis.

PURPOSE: Intraventricular hemorrhage (IVH) affects approximately 50% of premature births where 50% further develop post-hemorrhagic ventricular dilation (PHVD). Patients face significant impact to long-term development if PHVD is not managed. Unfortunately, there is no accepted treatment to remove the thrombus caused by IVH. This paper describes an acute and chronic IVH model for use with magnetic resonance-guided focused ultrasound (MRgFUS) thrombolysis. METHODS: A total of 12 pigs (~ 1 month in age) were used in the model (eight acute and four chronic). A pre-operative brain MRI was obtained for ventricular targeting. 1.25 cm3/kg of autologous blood was injected through a burr hole lateral to the midline and anterior of the coronal suture at a rate of 0.6 cm3/min. A craniotomy was performed to simulate a "fontanelle". Post-operative MRI was used to calculate the clot volume. Chronic piglets were recovered, monitored daily with a neurological scoring system (NSS), and MRI scanned for 21 days. RESULTS: The clot injection was well tolerated. The average clot size was 3987 mm3 (median = 4330 mm, standard deviation = 739 mm3). Postmortem examination validated the presence of the clot. In the chronic animals, there was an increase in ventricular volume of 30%. Transient neurological impairment immediately followed clot injection and with onset of hydrocephalus in the chronic animals. CONCLUSIONS: This model establishes a measurable and targetable IVH clot in an MRI-based neonatal porcine model. The progressive post-hemorrhagic ventricular dilation in the chronic model is a potential alterable outcome from MRgFUS thrombolysis.

Design and validation of a hemispherectomy simulator for neurosurgical education.

OBJECTIVE: Early adaptors of surgical simulation have documented a translation to improved intraoperative surgical performance. Similar progress would boost neurosurgical education, especially in highly nuanced epilepsy surgeries. This study introduces a hands-on cerebral hemispheric surgery simulator and evaluates its usefulness in teaching epilepsy surgeries. METHODS: Initially, the anatomical realism of the simulator and its perceived effectiveness as a training tool were evaluated by two epilepsy neurosurgeons. The surgeons independently simulated hemispherotomy procedures and provided questionnaire feedback. Both surgeons agreed on the anatomical realism and effectiveness of this training tool. Next, construct validity was evaluated by modeling the proficiency (task-completion time) of 13 participants, who spanned the experience range from novice to expert. RESULTS: Poisson regression yielded a significant whole-model fit (χ2 = 30.11, p < 0.0001). The association between proficiency when using the training tool and the combined effect of prior exposure to hemispherotomy surgery and career span was statistically significant (χ2 = 7.30, p = 0.007); in isolation, pre-simulation exposure to hemispherotomy surgery (χ2 = 6.71, p = 0.009) and career length (χ2 = 14.21, p < 0.001) were also significant. The mean (± SD) task-completion time was 25.59 ± 9.75 minutes. Plotting career length against task-completion time provided insights on learning curves of epilepsy surgery. Prediction formulae estimated that 10 real-life hemispherotomy cases would be needed to approach the proficiency seen in experts. CONCLUSIONS: The cerebral hemispheric surgery simulator is a reasonable epilepsy surgery training tool in the quest to increase preoperative practice opportunities for neurosurgical education.

Using robotics to move a neurosurgeon's hands to the tip of their endoscope.

A major advantage of surgical robots is that they can reduce the invasiveness of a procedure by enabling the clinician to manipulate tools as they would in open surgery but through small incisions in the body. Neurosurgery has yet to benefit from this advantage. Although clinical robots are available for the least invasive neurosurgical procedures, such as guiding electrode insertion, the most invasive brain surgeries, such as tumor resection, are still performed as open manual procedures. To investigate whether robotics could reduce the invasiveness of major brain surgeries while still providing the manipulation capabilities of open surgery, we created a two-armed joystick-controlled endoscopic robot. To evaluate the efficacy of this robot, we developed a set of neurosurgical skill tasks patterned after the steps of brain tumor resection. We also created a patient-derived brain model for pineal tumors, which are located in the center of the brain and are normally removed by open surgery. In comparison, testing with existing manual endoscopic instrumentation, we found that the robot provided access to a much larger working volume at the trocar tip and enabled bimanual tasks without compression of brain tissue adjacent to the trocar. Furthermore, many tasks could be completed faster with the robot. These results suggest that robotics has the potential to substantially reduce the invasiveness of brain surgery by enabling certain procedures currently performed as open surgery to be converted to endoscopic interventions.

Generation of normative pediatric skull models for use in cranial vault remodeling procedures.

PURPOSE: While the goal of craniofacial reconstruction surgery is to restore the cranial head shape as much towards normal as possible, for the individual patient, there is, in fact, no normal three-dimensional (3D) model to act as a guide. In this project, we generated a library of normative pediatric skulls from which a guiding template could be fabricated for a more standardized, objective and precise correction of craniosynostosis. METHODS: Computed tomography data from 103 normal subjects aged 8-12 months were compiled and a 3D computational model of the skull was generated for each subject. The models were mathematically registered to a baseline model for each month of age within this range and then averaged, resulting in a single 3D point cloud. An external cranial surface was subsequently passed through the point cloud and its shape and size customized to fit the head circumference of individual patients. RESULTS: The resultant fabricated skull models provide a novel and applicable tool for a detailed, quantitative comparison between the normative and patient skulls for preoperative planning and practice for a variety of craniofacial procedures including vault remodeling. Additionally, it was possible to extract the suprafrontal orbit anatomy from the normative model and fabricate a bandeau template to guide intraoperative reshaping. CONCLUSIONS: Normative head shapes for pediatric patients have wide application for craniofacial surgery including planning, practice, standarized operative repair, and standardized measurement and reporting of outcomes.

Associating Surgeon Feedback With Material Physical Properties in the Development Process of a Resective Epilepsy Surgery Simulator.

BACKGROUND: Hands-on neurosurgical simulations, specifically techniques involving white matter disconnection, are underdeveloped owing to the paucity of low indentation materials that can adequately mimic brain dissection. OBJECTIVE: To describe the discovery phase of developing a resective epilepsy surgery simulator by quantifying the physical properties of 6 materials and correlating the scores with surgeon feedback data. METHODS: Six materials, silicone, TissueMatrix, gel support, Synaptive hydrogel, dry SUP706, and moist SUP706 of equal dimension, were evaluated for hardness by measuring their resistance to indentation. Temporal lobe prototypes, 1 for each material, were dissected by 2 neurosurgeons and ordinal ranking assigned. Two null hypotheses were tested: one is that no differences in the indentation properties of the 6 materials analyzed would be elicited and the other is that there would be no correlation between indentation and surgeon feedback scores. Statistical comparison of the means of the different materials was performed using one-way analysis of variance. Surgeon feedback data and indentation score associations were analyzed using the Kendall rank correlation coefficient. RESULTS: A statistically significant effect (P value <.0001; α 0.05) was measured. Gel support and Synaptive hydrogel had the lowest indentation scores and similar physical properties. Moist support material scored lower than dry support (P = .0067). A strong positive correlation (Kendall tau = 0.9333, P < .0001) was ascertained between the surgeon feedback ranking and indentation scores. CONCLUSION: Reasonable material options for developing a resective epilepsy surgery are proposed and ranked in this article. Early involvement of surgeons is useful in the discovery phase of simulator invention.

A robotic magnetic resonance-guided high-intensity focused ultrasound platform for neonatal neurosurgery: Assessment of targeting accuracy and precision in a brain phantom.

BACKGROUND: Intraventricular hemorrhage (IVH) is one of the most serious neurovascular complications resulting from premature birth. It can result in clotting of blood within the ventricles, which causes a buildup of cerebrospinal fluid that can lead to posthemorrhagic ventricular dilation and posthemorrhagic hydrocephalus. Currently, there are no direct treatments for these blood clots as the standard of care is invasive surgery to insert a shunt. Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) has been investigated as a noninvasive treatment to lyse blood clots. However, current MRgHIFU systems are not suitable in the context of treating IVH in neonates. PURPOSE: We have developed a robotic MRgHIFU neurosurgical platform designed to treat the neonatal brain. This platform facilitates ergonomic patient positioning and directs treatment through their open anterior fontanelle while providing a larger treatment volume. The platform is based on an MR-compatible robot developed by our group. Further development of the platform has warranted investigation of its targeting ability to assess its feasibility in the neonatal brain. This study aimed to quantify the platform's targeting accuracy, precision, and repeatability using a brain phantom and clinical MRI system. METHODS: A thermosensitive brain-mimicking phantom was developed to test the platform's targeting accuracy. Rectangular grid patterns were created with HIFU thermal energy "lesions" in the phantoms by targeting specific coordinate points. The intended target locations were demarcated by inserting carbon fiber rods through a targeting assessment template. Coordinates for the intended and actual targets were derived from T2-weighted MRI scans, and the centroid distance between them was measured. Subsequently, the platform's targeting accuracy was quantified according to equations derived from ISO Standard 9283:1998. RESULTS: HIFU ablation resulted in distinct thermal lesions within the thermosensitive phantoms, which appeared as discrete hypointense regions in T2-weighted MR scans. A total of 127 target points were included in the data analysis, which yielded a targeting accuracy of 0.6 mm and targeting precision of 1.2 mm. CONCLUSIONS: The robotic MRgHIFU platform was shown to have a high degree of accuracy, precision, and repeatability. The results demonstrate the platform's functionality when targeting through simulated brain matter. These results serve as an initial verification of the platform targeting ability and showed promise toward the final application in a neonatal brain.

A robotic MR-guided high-intensity focused ultrasound platform for intraventricular hemorrhage: assessment of clot lysis efficacy in a brain phantom.

OBJECTIVE: Intraventricular hemorrhage (IVH) is a neurovascular complication due to premature birth that results in blood clots forming within the ventricles. Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) has been investigated as a noninvasive treatment to lyse clots. The authors designed and constructed a robotic MRgHIFU platform to treat the neonatal brain that facilitates ergonomic patient positioning. The clot lysis efficacy of the platform is quantified using a brain phantom and clinical MRI system. METHODS: A thermosensitive brain-mimicking phantom with ventricular cavities was developed to test the clot lysis efficacy of the robotic MRgHIFU platform. Whole porcine blood was clotted within the phantom's cavities. Using the MRgHIFU platform and a boiling histotripsy treatment procedure (500 W, 10-msec pulse duration, 1.0% duty cycle, and 40-second duration), the clots were lysed inside the phantom. The contents of the cavities were vacuum filtered, and the remaining mass of the solid clot particles was used to quantify the percentage of clot lysis. The interior of the phantom's cavities was inspected for any collateral damage during treatment. RESULTS: A total of 9 phantoms were sonicated, yielding an average (± SD) clot lysis of 97.0% ± 2.57%. Treatment resulted in substantial clot lysis within the brain-mimicking phantoms that were apparent on postsonication T2-weighted MR images. No apparent collateral damage was observed within the phantom after treatment. The results from the study showed the MRgHIFU platform was successful at lysing more than 90% of a blood clot at a statistically significant level. CONCLUSIONS: The robotic MRgHIFU platform was shown to lyse a large percentage of a blood clot with no observable collateral damage. These results demonstrate the platform's ability to induce clot lysis when targeting through simulated brain matter and show promise toward the final application in neonatal patients.

Preliminary Study of a Modular MR-Compatible Robot for Image-Guided Insertion of Multiple Needles.

Percutaneous needle-based interventions such as transperineal prostate brachytherapy require the accurate placement of multiple needles to treat cancerous lesions within the target organ. To guide needle placement, magnetic resonance imaging (MRI) offers excellent visualization of the target lesion without the need for ionizing radiation. To date, multi-needle insertion relies on a grid template, which limits the ability to steer individual needles. This work describes an MR-compatible robot designed for the sequential insertion of multiple non-parallel needles under MR guidance. The 6-DOF system is designed with an articulated arm to extend the reach of the robot. This strategy presents a novel approach enabling the robot to maneuver around existing needles while minimizing the footprint of the robot. Forward kinematics as well as optimization-based inverse kinematics are presented. The impact of the robot on image quality was tested for four sequences (T1w-TSE, T2w-TSE, THRIVE and EPI) on a 3T Philips Achieva system. Quantification of the signal-to-noise ratio showed a 46% signal loss in a gelatin phantom when the system was powered on but no further adverse effects when the robot was moving. Joint level testing showed a maximum error of 2.10 ± 0.72°s for revolute joints and 0.31 ± 0.60 mm for prismatic joints. The theoretical workspace spans the proposed clinical target surface of 10 x 10 cm. Lastly, the feasibility of multi-needle insertion was demonstrated with four needles inserted under real-time MR-guidance with no visible loss in image quality.

Prediction of persistent ventricular dilation by initial ventriculomegaly and clot volume in a porcine model.

OBJECTIVE: While intraventricular hemorrhage (IVH) is associated with posthemorrhagic ventricular dilation (PHVD), not all infants affected by high-grade IVH develop PHVD. The authors aimed to determine clot-associated predictors of PHVD in a porcine model by varying the amount and rate of direct intraventricular injection of whole autologous blood. METHODS: Seven 1-week-old piglets underwent craniectomy and injection of autologous blood into the right lateral ventricle. They survived for a maximum of 28 days. MRI was performed prior to injection, immediately postoperatively, and every 7 days thereafter. T1-weighted, T2-weighted, and susceptibility-weighted imaging (SWI) sequences were used to segment ventricular and clot volumes. Spearman correlations were used to determine the relationship between blood and clot volumes and ventricular volumes over time. RESULTS: The maximum ventricular volume was up to 12 times that of baseline. One animal developed acute hydrocephalus on day 4. All other animals survived until planned endpoints. The interaction between volume of blood injected and duration of injection was significantly associated with clot volume on the postoperative scan (p = 0.003) but not the amount of blood injected alone (p = 0.38). Initial postoperative and day 7 clot volumes, but not volume of blood injected, were correlated with maximum (p = 0.007 and 0.014) and terminal (p = 0.014 and 0.036) ventricular volumes. Initial postoperative ventricular volume was correlated with maximum and terminal ventricular volume (p = 0.007 and p = 0.014). CONCLUSIONS: Initial postoperative, maximum, and terminal ventricular dilations were associated with the amount of clot formed, rather than the amount of blood injected. This supports the hypothesis that PHVD is determined by clot burden rather than the presence of blood products and allows further testing of early clot lysis to minimize PHVD risk.

Effect of Wearing a Face Mask on Hand-to-Face Contact by Children in a Simulated School Environment: The Back-to-School COVID-19 Simulation Randomized Clinical Trial.

Importance: Wearing a face mask in school can reduce SARS-CoV-2 transmission but it may also lead to increased hand-to-face contact, which in turn could increase infection risk through self-inoculation. Objective: To evaluate the effect of wearing a face mask on hand-to-face contact by children while at school. Design, Setting, and Participants: This prospective randomized clinical trial randomized students from junior kindergarten to grade 12 at 2 schools in Toronto, Ontario, Canada, during August 2020 in a 1:1 ratio to either a mask or control class during a 2-day school simulation. Classes were video recorded from 4 angles to accurately capture outcomes. Interventions: Participants in the mask arm were instructed to bring their own mask and wear it at all times. Students assigned to control classes were not required to mask at any time (grade 4 and lower) or in the classroom where physical distancing could be maintained (grade 5 and up). Main Outcomes and Measures: The primary outcome was the number of hand-to-face contacts per student per hour on day 2 of the simulation. Secondary outcomes included hand-to-mucosa contacts and hand-to-nonmucosa contacts. A mixed Poisson regression model was used to derive rate ratios (RRs), adjusted for age and sex with a random intercept for class with bootstrapped 95% CIs. Results: A total of 174 students underwent randomization and 171 students (mask group, 50.6% male; control group, 52.4% male) attended school on day 2. The rate of hand-to-face contacts did not differ significantly between the mask and the control groups (88.2 vs 88.7 events per student per hour; RR, 1.00; 95% CI, 0.78-1.28; P = >.99). When compared with the control group, the rate of hand-to-mucosa contacts was significantly lower in the mask group (RR, 0.12; 95% CI, 0.07-0.21), while the rate of hand-to-nonmucosa contacts was higher (RR, 1.40; 95% CI, 1.08-1.82). Conclusions and Relevance: In this clinical trial of simulated school attendance, hand-to-face contacts did not differ among students required to wear face masks vs students not required to wear face masks; however, hand-to-mucosa contracts were lower in the face mask group. This suggests that mask wearing is unlikely to increase infection risk through self-inoculation. Trial Registration: ClinicalTrials.gov Identifier: NCT04531254.

Application of CAD/CAM prefabricated age-matched templates in cranio-orbital remodeling in craniosynostosis.

Infants with craniosynostosis involving the metopic and coronal sutures require cranio-orbital reshaping to correct craniofacial dysmorphologic feature and to improve facial balance. Currently, surgical techniques to create a balanced fronto-orbital region are based on the surgeon's subjective approach and artistic vision in creating a normal shape to the forehead. To date, the use of age-matched templates and computer-assisted design/computer-assisted manufacturing techniques in optimizing the outcomes of surgical intervention in this area have not been explored. The aim of this article was to describe the process of template generation and application based on age-matched controls using computer-assisted design/computer-assisted manufacturing technology and to present this application in 2 cases.

Application of 3D Printing Support Material for Neurosurgical Simulation.

Brain dissection, an intricate neurosurgical skill, is central to life-saving procedures such as intrinsic brain tumor excision and resective epilepsy surgery. The aims of this manuscript are to outline the selection process of a suitable material for the development of a dissectible brain simulator and to present the use of support material, SUP 706, manufactured by Stratasys Ltd. as a non-waste alternative for sustainably engineering solutions for surgical education. A feasibility study was conducted through qualitative function deployment (QFD) followed by a material selection process. End-user requirements and manufacturing product characteristics were incorporated into the workflow. Three materials, silicone, TissueMatrix™ and support material each formed the primary component of the first two prototypes. Expert feedback, manufacturing cost, safety profiling, functional fidelity and post-processing time data were collected and analyzed. The unique break-away feature of moist support material was found to be more suitable than using silicone or TissueMatrix™ for demonstrating brain dissection techniques. In addition, support material displayed higher functional fidelity by mimicking surgical tissues such as pia mater, gray and white matter, and blood vessels. The cost of the support material prototype was 39% less that of TissueMatrix™ and roughly the same as the silicone model. It took twice as long to post-process the support material prototype than it did the TissueMatrix™ design. Support material lost its ideal dissection properties and began to disintegrate after 30 - 45 minutes. In conclusion 3D printer support material is a low-cost material for a dissectible brain simulator.Clinical Relevance- The use of support material as the primary material in developing a dissectible brain simulator is a promising way of advancing neurosurgical education.

Manual Shunt Connector Tool to Aid in No-Touch Technique.

BACKGROUND: Given the morbidity and cost associated with cerebrospinal fluid shunt infections, many neurosurgical protocols implement "no-touch" technique to minimize infection. However, current surgical tools are not designed specifically for this task and surgeons often resort to using their hands to connect the shunt catheter to the valve. OBJECTIVE: To develop an efficient and effective shunt assembly tool. METHODS: Prototypes were designed using computer assisted software and machined in stainless steel. The amount of time and number of attempts it took volunteers to connect a Bacticel shunt catheter to a Delta valve were recorded using the new tool and standard shodded mosquitos. Scanning electron microscopy (SEM) was done on manipulated catheters to assess potential damage. Practicing neurosurgeons provided feedback. RESULTS: Nonsurgeon (n = 13) volunteers and neurosurgeons (n = 6) both completed the task faster and with fewer attempts with the new tool (mean 7.18 vs 15.72 s and 2.00 vs 6.36 attempts, P < .0001; mean 2.93 vs 5.96 s and 1.06 vs 2.94 attempts, P < .001, respectively). SEM of 24 manipulated catheters showed no microscopic damage. 100% of neurosurgeons surveyed (n = 10) would adapt the tool in their practice, 90% preferred use of the new tool compared to their existing method, and 100% rated it easier to use compared to existing instruments. CONCLUSION: The new tool shortened the time and number of attempts to connect a shunt catheter to a valve. Neurosurgeons preferred the new tool to existing instruments. There was no evidence of catheter damage with the use of this tool.

Design and Comparison of Magnetically-Actuated Dexterous Forceps Instruments for Neuroendoscopy.

Robot-assisted minimally invasive surgical (MIS) techniques offer improved instrument precision and dexterity, reduced patient trauma and risk, and promise to lessen the skill gap among surgeons. These approaches are common in general surgery, urology, and gynecology. However, MIS techniques remain largely absent for surgical applications within narrow, confined workspaces, such as neuroendoscopy. The limitation stems from a lack of small yet dexterous robotic tools. In this work, we present the first instance of a surgical robot with a direct magnetically-driven end effector capable of being deployed through a standard neuroendoscopic working channel (3.2 mm outer diameter) and operate at the neuroventricular scale. We propose a physical model for the gripping performance of three unique end-effector magnetization profiles and mechanical designs. Rates of blocking force per external magnetic flux density magnitude were 0.309 N/T, 0.880 N/T, and 0.351 N/T for the three designs which matched the physical model's prediction within 14.9% error. The rate of gripper closure per external magnetic flux density had a mean percent error of 11.2% compared to the model. The robot's performance was qualitatively evaluated during a pineal region tumor resection on a tumor analogue in a silicone brain phantom. These results suggest that wireless magnetic actuation may be feasible for dexterously manipulating tissue during minimally invasive neurosurgical procedures.

Synthetic Simulator for Surgical Training in Tracheostomy and Open Airway Surgery.

OBJECTIVE(S): To create and validate a synthetic simulator for teaching tracheostomy and laryngotracheal reconstruction (LTR) using anterior costal cartilage and thyroid ala cartilage grafts. METHODS: A late adolescent/adult neck and airway simulator was constructed based on CT scans from a cadaver and a live patient. Images were segmented to create three-dimensional printed molds from which anatomical parts were casted. To evaluate the simulator, expert otolaryngologists - head and neck surgeons performed tracheostomy and LTR using anterior costal cartilage and thyroid ala cartilage grafts on a live anesthetized porcine model (gold standard) followed by the synthetic simulator. They evaluated each model for face validity (realism and anatomical accuracy) and content validity (perceived effectiveness as a training tool) using a five-point Likert scale. For each expert, differences for each item on each simulator were compared using Wilcoxon Signed-Rank tests with Sidak correction. RESULTS: Nine expert faculty surgeons completed the study. Experts rated face and content validity of the synthetic simulator an overall median of 4 and 5, respectively. There was no difference in scores between the synthetic model and the live porcine model for any of the steps of any of the surgical procedures. CONCLUSION: The synthetic simulator created for this study has high face and content validity for tracheostomy and LTR with anterior costal cartilage and thyroid ala cartilage grafts and was not found to be different than the live porcine model for these procedures. LEVEL OF EVIDENCE: 5 Laryngoscope, 131:E2378-E2386, 2021.

A Novel Bipolar Cautery Tool for Minimally-Invasive Neuroendoscopic Procedures.

Electrosurgery is used in the operating room on a daily basis as a means to cut tissue and maintain hemostasis. The principle of this technology lies in the transfer of electricity from an electrosurgical unit to the operating site on a patient's body and modifying the waveform of that electricity to achieve the desired surgical effect. Bipolar cautery uses two electrodes, an active and a return, both at the surgical site to perform electrosurgery. Bipolar cautery can be very useful in helping surgeons to operate; however, current designs are not well suited to a 2.1 mm working channel in endoscopic procedures due to their rigid structure, limited range of motion, and bulky design. This paper describes a novel approach to designing a minimally- invasive bipolar cautery tool suitable for flexible neuroendoscopy. The system features 1.9 mm diameter bipolar tips which resemble grasping forceps, making it easier for surgeons to hold tissue while performing electrosurgery. The electrode wires also function as the actuating cables used to open and close the tips, which require 2.10 mm to open the tips to 30.9 °. The results show that the tool can safely cauterize a porcine brain specimen at various settings on the electrosurgical unit, and increasing the setting increases the area of tissue affected by the electricity. Repeatability was demonstrated and exhaustion was reached after the tool was opened and closed 73 times. Future work will involve improving the current design to increase the number of cycles the tool can survive before losing function.

Live porcine model for surgical training in tracheostomy and open-airway surgery.

OBJECTIVES/HYPOTHESIS: To evaluate the validity of a live porcine model for surgical training in tracheostomy and open-airway surgery. STUDY DESIGN: Prospective observational study. METHODS: Eleven expert otolaryngologists-head and neck surgeons rated a live porcine model's realism/anatomical accuracy (face validity) and perceived effectiveness as a training tool (content validity) for tracheostomy and laryngotracheoplasty using anterior costal cartilage and thyroid ala cartilage grafts using a 53-item post-trial questionnaire with a five-point Likert scale. RESULTS: Experts rated the face validity of the live porcine model a median (interquartile range [IQR]) of 4/5 (4-5) and the content validity a median (IQR) of 5/5 (4-5) for each surgical procedure. Overall, 91% strongly agreed or agreed that the simulator would increase trainee competency for tracheostomy and laryngotracheoplasty using costal cartilage graft, and 82% strongly agreed or agreed that it would increase trainee competency for laryngotracheoplasty using thyroid ala cartilage graft. CONCLUSIONS: The live porcine model has high face and content validity as a training tool for tracheostomy and laryngotracheoplasty using costal cartilage and thyroid ala cartilage grafts. This training model can help surgical trainees practice these complex, low-frequency procedures. LEVEL OF EVIDENCE: NA Laryngoscope, 130: 2063-2068, 2020.

Bone Conduction Headphones for Force Feedback in Robotic Surgery.

Bone conduction headphones (Fig. 1) offer the unique ability to provide auditory information to the user without obstructing external sounds. We apply this technology to robotic surgery to provide the surgeon with force feedback information with minimal distraction. The device is evaluated by pairing it with a force sensor that is attached to a suture pad. Four participants were tasked to complete 25 sutures on the suture pad while either receiving no feedback or audio, visual, or combined feedback that represents the magnitude of their applied force. Trials performed with bone conducting headphones had noticeable improvements compared to previous trials without feedback, while the most noticeable improvements were observed for cases with both visual and auditory feedback. Auditory feedback may have an important role in a robotic surgery setting and bone conduction headphones may enable this form of feedback with minimal distraction.

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.