Usefulness of Three-Dimensional Modeling in Surgical Planning, Resident Training, and Patient Education.

BACKGROUND: Imaging has a critical impact on surgical decision making and three-dimensional (3D) digital models of patient pathology can now be made commercially. We developed a 3D digital model of a cancer of the head of the pancreas by integrating actual CT data with 3D modeling process. After this process, the virtual pancreatic model was also produced using a high-quality 3D printer. PATIENTS AND METHODS: A 56-year-old female with pancreatic head adenocarcinoma presented with biliary obstruction and jaundice. The CT scan showed a borderline resectable tumor with a clear involvement of the gastroduodenal artery but doubtful relationships with the hepatic artery. Our team in collaboration with the Immersive Touch team used multiple series from the CT and segmented the relevant anatomy to understand the physical location of the tumor. An STL file was then developed and printed. RESULTS: Reconstructing and compositing the different series together enhanced the imaging, which allowed clearer observations of the relationship between the mass and the blood vessels, and evidence that the tumor was unresectable. Data files were converted for printing a 100% size rendering model, used for didactic purposes and to discuss with the patient. CONCLUSIONS: This study showed that (1) reconstructing enhanced traditional imaging by merging and modeling different series together for a 3D view with diverse angles and transparency, allowing the observation of previously unapparent anatomical details; (2) with this new technology surgeons and residents can preobserve their planned surgical intervention, explore the patient-specific anatomy, and sharpen their procedure choices; (3) high-quality 3D printed models are increasingly useful not only in the clinical realm but also for personalized patient education.

Evaluation of Sensory and Motor Skills in Neurosurgery Applicants Using a Virtual Reality Neurosurgical Simulator: The Sensory-Motor Quotient.

OBJECTIVE: Manual skill is an important attribute for any surgeon. Current methods to evaluate sensory-motor skills in neurosurgical residency applicants are limited. We aim to develop an objective multifaceted measure of sensory-motor skills using a virtual reality surgical simulator. DESIGN: A set of 3 tests of sensory-motor function was performed using a 3-dimensional surgical simulator with head and arm tracking, collocalization, and haptic feedback. (1) Trajectory planning: virtual reality drilling of a pedicle. Entry point, target point, and trajectory were scored-evaluating spatial memory and orientation. (2) Motor planning: sequence, timing, and precision: hemostasis in a postresection cavity in the brain. (3) Haptic perception: touching virtual spheres to determine which is softest of the group, with progressive difficulty. Results were analyzed individually and for a combined score of all the tasks. SETTING: The University of Chicago Hospital's tertiary care academic center. PARTICIPANTS: A total of 95 consecutive applicants interviewed at a neurosurgery residency program over 2 years were offered anonymous participation in the study; in 2 cohorts, 36 participants in year 1 and 27 participants in year 2 (validation cohort) agreed and completed all the tasks. We also tested 10 first-year medical students and 4 first- and second-year neurosurgery residents. RESULTS: A cumulative score was generated from the 3 tests. The mean score was 14.47 (standard deviation = 4.37), median score was 13.42, best score was 8.41, and worst score was 30.26. Separate analysis of applicants from each of 2 years yielded nearly identical results. Residents tended to cluster on the better performance side, and first-year students were not different from applicants. CONCLUSIONS: (1) Our cumulative score measures sensory-motor skills in an objective and reproducible way. (2) Better performance by residents hints at validity for neurosurgery. (3) We were able to demonstrate good psychometric qualities and generate a proposed sensory-motor quotient distribution in our tested population.

Usefulness of a Virtual Reality Percutaneous Trigeminal Rhizotomy Simulator in Neurosurgical Training.

BACKGROUND: Simulation-based training may be incorporated into neurosurgery in the future. OBJECTIVE: To assess the usefulness of a novel haptics-based virtual reality percutaneous trigeminal rhizotomy simulator. METHODS: A real-time augmented reality simulator for percutaneous trigeminal rhizotomy was developed using the ImmersiveTouch platform. Ninety-two neurosurgery residents tested the simulator at American Association of Neurological Surgeons Top Gun 2014. Postgraduate year (PGY), number of fluoroscopy shots, the distance from the ideal entry point, and the distance from the ideal target were recorded by the system during each simulation session. Final performance score was calculated considering the number of fluoroscopy shots and distances from entry and target points (a lower score is better). The impact of PGY level on residents' performance was analyzed. RESULTS: Seventy-one residents provided their PGY-level and simulator performance data; 38% were senior residents and 62% were junior residents. The mean distance from the entry point (9.4 mm vs 12.6 mm, P = .01), the distance from the target (12.0 mm vs 15.2 mm, P = .16), and final score (31.1 vs 37.7, P = .02) were lower in senior than in junior residents. The mean number of fluoroscopy shots (9.8 vs 10.0, P = .88) was similar in these 2 groups. Linear regression analysis showed that increasing PGY level is significantly associated with a decreased distance from the ideal entry point (P = .001), a shorter distance from target (P = .05), a better final score (P = .007), but not number of fluoroscopy shots (P = .52). CONCLUSION: Because technical performance of percutaneous rhizotomy increases with training, we proposed that the skills in performing the procedure in our virtual reality model would also increase with PGY level, if our simulator models the actual procedure. Our results confirm this hypothesis and demonstrate construct validity.

The use of a virtual reality surgical simulator for cataract surgical skill assessment with 6 months of intervening operating room experience.

PURPOSE: To evaluate a haptic-based simulator, MicroVisTouch™, as an assessment tool for capsulorhexis performance in cataract surgery. The study is a prospective, unmasked, nonrandomized dual academic institution study conducted at the Wilmer Eye Institute at Johns Hopkins Medical Center (Baltimore, MD, USA) and King Khaled Eye Specialist Hospital (Riyadh, Saudi Arabia). METHODS: This prospective study evaluated capsulorhexis simulator performance in 78 ophthalmology residents in the US and Saudi Arabia in the first round of testing and 40 residents in a second round for follow-up. RESULTS: Four variables (circularity, accuracy, fluency, and overall) were tested by the simulator and graded on a 0-100 scale. Circularity (42%), accuracy (55%), and fluency (3%) were compiled to give an overall score. Capsulorhexis performance was retested in the original cohort 6 months after baseline assessment. Average scores in all measured metrics demonstrated statistically significant improvement (except for circularity, which trended toward improvement) after baseline assessment. A reduction in standard deviation and improvement in process capability indices over the 6-month period was also observed. CONCLUSION: An interval objective improvement in capsulorhexis skill on a haptic-enabled cataract surgery simulator was associated with intervening operating room experience. Further work investigating the role of formalized simulator training programs requiring independent simulator use must be studied to determine its usefulness as an evaluation tool.

Neurosurgical tactile discrimination training with haptic-based virtual reality simulation.

OBJECTIVE: To determine if a computer-based simulation with haptic technology can help surgical trainees improve tactile discrimination using surgical instruments. MATERIAL AND METHODS: Twenty junior medical students participated in the study and were randomized into two groups. Subjects in Group A participated in virtual simulation training using the ImmersiveTouch simulator (ImmersiveTouch, Inc., Chicago, IL, USA) that required differentiating the firmness of virtual spheres using tactile and kinesthetic sensation via haptic technology. Subjects in Group B did not undergo any training. With their visual fields obscured, subjects in both groups were then evaluated on their ability to use the suction and bipolar instruments to find six elastothane objects with areas ranging from 1.5 to 3.5 cm2 embedded in a urethane foam brain cavity model while relying on tactile and kinesthetic sensation only. RESULTS: A total of 73.3% of the subjects in Group A (simulation training) were able to find the brain cavity objects in comparison to 53.3% of the subjects in Group B (no training) (P  =  0.0183). There was a statistically significant difference in the total number of Group A subjects able to find smaller brain cavity objects (size ≤ 2.5 cm2) compared to that in Group B (72.5 vs. 40%, P  =  0.0032). On the other hand, no significant difference in the number of subjects able to detect larger objects (size ≧ 3 cm2) was found between Groups A and B (75 vs. 80%, P  =  0.7747). CONCLUSION: Virtual computer-based simulators with integrated haptic technology may improve tactile discrimination required for microsurgical technique.

Virtual reality spine surgery simulation: an empirical study of its usefulness.

OBJECTIVE: This study explores the usefulness of virtual simulation training for learning to place pedicle screws in the lumbar spine. METHODS: Twenty-six senior medical students anonymously participated and were randomized into two groups (A = no simulation; B = simulation). Both groups were given 15 minutes to place two pedicle screws in a sawbones model. Students in Group A underwent traditional visual/verbal instruction whereas students in Group B underwent training on pedicle screw placement in the ImmersiveTouch simulator. The students in both groups then placed two pedicle screws each in a lumbar sawbones models that underwent triplanar thin slice computerized tomography and subsequent analysis based on coronal entry point, axial and sagittal deviations, length error, and pedicle breach. The average number of errors per screw was calculated for each group. Semi-parametric regression analysis for clustered data was used with generalized estimating equations accommodating a negative binomial distribution to determine any statistical difference of significance. RESULTS: A total of 52 pedicle screws were analyzed. The reduction in the average number of errors per screw after a single session of simulation training was 53.7% (P  =  0.0067). The average number of errors per screw in the simulation group was 0.96 versus 2.08 in the non-simulation group. The simulation group outperformed the non-simulation group in all variables measured. The three most benefited measured variables were length error (86.7%), coronal error (71.4%), and pedicle breach (66.7%). CONCLUSIONS: Computer-based simulation appears to be a valuable teaching tool for non-experts in a highly technical procedural task such as pedicle screw placement that involves sequential learning, depth perception, and understanding triplanar anatomy.

A novel virtual reality simulation for hemostasis in a brain surgical cavity: perceived utility for visuomotor skills in current and aspiring neurosurgery residents.

OBJECTIVE: To understand the perceived utility of a novel simulator to improve operative skill, eye-hand coordination, and depth perception. METHODS: We used the ImmersiveTouch simulation platform (ImmersiveTouch, Inc., Chicago, Illinois, USA) in two U.S. Accreditation Council for Graduate Medical Education-accredited neurosurgical training programs: the University of Chicago and the University of Texas Medical Branch. A total of 54 trainees participated in the study, which consisted of 14 residents (group A), 20 senior medical students who were neurosurgery candidates (group B), and 20 junior medical students (group C). The participants performed a simulation task that established bipolar hemostasis in a virtual brain cavity and provided qualitative feedback regarding perceived benefits in eye-hand coordination, depth perception, and potential to assist in improving operating skills. RESULTS: The perceived ability of the simulator to positively influence skills judged by the three groups: group A, residents; group B, senior medical students; and group C, junior medical students was, respectively, 86%, 100%, and 100% for eye-hand coordination; 86%, 100%, and 95% for depth perception; and 79%, 100%, and 100% for surgical skills in the operating room. From all groups, 96.2% found the simulation somewhat or very useful to improve eye-hand coordination, and 94% considered it beneficial to improve depth perception and operating room skills. CONCLUSION: This simulation module may be suitable for resident training, as well as for the development of career interest and skill acquisition; however, validation for this type of simulation needs to be further developed.

Sensory and motor skill testing in neurosurgery applicants: a pilot study using a virtual reality haptic neurosurgical simulator.

BACKGROUND: Manual skill is important for surgeons, but current methods to evaluate sensory-motor skills in applicants to a surgical residency are limited. OBJECTIVE: To develop a method of testing sensory-motor skill using objective and reproducible virtual reality simulation. METHODS: We designed a set of tests on a 3-dimensional surgical simulator with head and arm tracking, colocalization, and haptic feedback: (1) "trajectory planning in a simulated vertebra," ie, 3-dimensional memory and orientation; "hemostasis in the brain," ie, motor planning, sequence, timing, and precision; and "choose the softest object," ie, haptic perception. We also derived a weighted combined score for all tasks. RESULTS: Of the 55 consecutive applicants to a neurosurgery residency approached, 46 performed at least 1 task, and 36 performed all tasks. For the trajectory planning task, the distance from target ranged from 3 to 30 mm, with 25 of 36 in the 6- to 18-mm range. In the motor planning test, the duration between cauterization attempts ranged between 5 and 22.5 seconds, peaking at 10 to 12.5 seconds in 15 of 36 participants. In the haptic perception test, linear regression demonstrated increased variability in performance with increasing difficulty of task (R = 0.6281). In all tests, performance followed a roughly bell-shaped curve. The combined weighted score of all tests demonstrated a better bell curve distribution, with scores ranging from 0.275 to 0.71 (mean, 0.47; median, 0.4775; SD, 0.1174). CONCLUSION: Our study represents a first step in the direction of an objective, standard, computer-scored test of motor and haptic ability.