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Abstract
Background We have previously reported the efficacy of a simulator-based training paradigm for residents in neurosurgery with little or no prior experience in diagnostic cerebral angiography with straightfoward arch anatomy. This study investigates the utility of a simulation-based training curriculum for the acquisition of skills employing a secondary curve catheter to navigate more complex arch anatomy.
Methods Residents at the Medical University of South Carolina (MUSC) with moderate exposure to diagnostic angiography enrolled into a standardized Institutional Review Board-approved training protocol using SimSuite Compass and Simbionix simulators. The task involved (in order) forming the Simmons catheter in the left subclavian artery and then selecting the brachiocephalic, left common carotid and left vertebral arteries.
Results All participants improved their total time to complete the task over the course from the first to last trial. Each milestone within the overall task also demonstrated an improvement across trials for each participant. Following the hands-on experience, participants’ rating of their knowledge of arch anatomy and vessel selection technique improved to that between competence and high competence (values of 3.3±0.49 (p<0.005) and 3.1±0.38 (p<0.01), respectively). Comfort with use of the Simmons catheter improved to a value of 2.9±0.38 (p<0.001), between an experienced learner and competence. Participants rated the usefulness of the training environment as very high (4.1±0.90 out of maximum 5).
Conclusions Residents became more proficient at vessel selection in a type II and bovine arch over a relatively compressed time period, with both objective and subjective data demonstrating acquisition of skill sets and increased confidence.
- Angiography
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Introduction
The use of technology for simulation-based training has been widely accepted throughout medicine and holds great promise in the field of neuroendovascular surgery. Neuroendovascular simulation provides a zero-risk setting in which technical skills can be acquired through repetition and, as the technology progresses and curricula develop, it is likely to become an integral component of resident and fellow training.1 ,2 Training through simulation is further enhanced when expert interventionalists are present to provide feedback and ensure safe techniques are employed and to ensure that poor habits are not formed.3 The fundamental prerequisite skill set required to succeed in neuroendovascular surgery is vessel selection. Prior to developing microcatheter navigation skills and aneurysm coil selection strategies, safe navigation from the aortic arch into the great vessels for the purposes of performing diagnostic angiography and for guide catheter placement is required. Arch and great vessel anatomy can vary widely, requiring comfort and proficiency with a wide selection of catheters to achieve competence.
We have previously reported the efficacy of a simulator-based training paradigm for residents in neurosurgery with little or no prior experience in diagnostic cerebral angiography.4 That pilot program used a simple type I arch as the platform upon which to learn basic vessel selection technique with a primary curve catheter. This study investigates the utility of a simulation-based training curriculum for the acquisition of skills employing a secondary curve catheter to navigate more complex arch anatomy.
Methods
Seven neurosurgical residents in their postgraduate years 1–7 from the Medical University of South Carolina enrolled into a standardized pilot training protocol. The residents all had previous exposure to diagnostic angiography.
Neuroendovascular simulator
The SimSuite Compass (Medical Simulation Corporation, Denver, Colorado, USA) and Simbionix (Simbionix USA Corp, Cleveland, Ohio, USA) simulators were employed. Both simulators provide an interactive biplanar fluoroscopic display to perform both diagnostic and interventional procedures on a number of case scenarios with unique vasculatures. A broad selection of diagnostic catheters and guidewires may be selected and the software incorporates the unique mechanical properties of each. While the behavior of the catheter in the vessel is simulated, actual catheter and wire manipulations are incorporated by motion tracking sensing capabilities. Trainees were randomized to one of the simulators and randomized to either a type II arch or an arch with a shared origin of the brachiocephalic and left common carotid artery (bovine).
Pre-task survey
Participants were asked the number of cerebral angiograms they had observed and performed. They were asked to rate their knowledge of the anatomy of the aortic arch and their level of comfort on vessel selection technique in general as well as in secondary curve catheter vessel selection technique (scale 1–5: 0=no knowledge, 1=novice, 2=experienced learner, 3=competent, 4=high competence, 5=expert).
Training exercise
The training protocol consisted of a didactic, demonstration and hands-on learning environment. The didactic was a 5 min Power Point presentation that covered basic arch anatomy, reviewed vessel selection with a primary curve catheter, introduced the challenges of complex arch anatomy, and finally described the technique and advantages afforded by a secondary curve catheter. Each participant then observed a demonstration of vessel selection technique employing a Simmons 2 catheter of the arch to which they were randomized. Following the demonstration, participants were asked to navigate the arch for the purposes of cerebral angiography five times. The task involved (in order) forming the Simmons catheter in the left subclavian artery and then selecting the brachiocephalic, left common carotid and left vertebral arteries. Total procedure time and time to achieve each of the milestones in the task were recorded.
Post-task survey
Following task completion, participants were asked to rate their level of comfort with arch anatomy, vessel selection technique in general, and with a Simmons catheter using the same 0–5 scale as employed in the pre-task survey. They were asked to rate how useful they found the training exercise as well as to rate the relative usefulness of each component of the exercise.
Results
Pre-task survey
On average, participants had observed 23±5.3 cerebral angiograms, performed 9±7.9 (range 1–25) diagnostic cerebral angiograms and observed 4±5.0 (range 0–11) cerebral angiograms with a Simmons catheter. Knowledge of arch anatomy was rated as 2.6±0.79 (between an experienced learner and competence), knowledge of vessel selection technique in general as 1.8±0.69 (between novice and experienced learner), and comfort with use of the Simmons catheter was rated as 0.7±0.76 (between no knowledge at all and a novice).
Training exercise
All participants improved their total time to complete the task over the course from the first to last trial (figure 1). On average, participants improved the overall time required to complete the task by 232±73 s (61% improvement, p<0.0001). Each milestone within the overall task also demonstrated an improvement across trials for each participant (figure 2). The average time required to place a guidewire into the left subclavian artery improved from trial 1 to 5 (from 123.9 s to 43.9 s; p<0.01) and the average time required to form the Simmons in the left subclavian artery also improved across trials (from 64.4 s to 26.9 s; p=0.064). The average time required to select the right common carotid artery once the Simmons was formed (from 60.7 s to 20.6 s; p=0.04) and to select the left common carotid artery (from 78.1 s to 30.1 s; p=0.017) improved from trial 1 to 5 and the mean time to select the left vertebral artery also improved (from 44.7 s to 18.4 s; p=0.008).
Composition of the total time to complete the simulated procedure for each resident. (A) Postgraduate years (PGY)-1 Simbionix; (B) PGY-2 Simbionix; (C) PGY-3 Simsuite; (D) PGY-3 Simbionix; (E) PGY-4 SimSuite; (F) PGY-5 SimSuite; (G) PGY-7 Simbionix.
Mean time by run number (1–5) it took participants to complete each step in the simulated procedure. (A) Mean time to wire the left subclavian artery (p<0.01). (B) Mean time to form the Simmons catheter (p=0.06). (C) Mean time to catheter the right common carotid artery (p<0.05). (D) Mean time to catheter the left common carotid artery (p<0.05). (E) Mean time to catheter the left vertebral artery (p<0.01). (F) Mean time to complete the entire procedure (p<0.0001).
Post-task survey
Following the didactic and hands-on experience, participants’ rating of their knowledge of arch anatomy and vessel selection technique improved to that between competence and high competence (values of 3.3±0.49 (p<0.005) and 3.1±0.38 (p<0.01), respectively). Comfort with use of the Simmons catheter improved to a value of 2.9 (p<0.001), between an experienced learner and competence. No pre-task survey information correlated with the final time to complete the simulation task.
Participants’ rating of the usefulness of the training environment was a 4.1±90 (range 3–5), with three of the seven participants identifying this exercise as ‘essential’.
Participants rated the hands-on component of the training exercise as most important (85%), followed by the demonstration (15%); no participants found the didactic portion as the most important.
Discussion
Historically, simulation training in the field of neuroendovascular surgery has been restricted to animal laboratories and flow models. The limitation of these is that they are costly and require waste of actual products and devices as well as cumulative radiation exposure. Endovascular training programs throughout the country have begun to adopt the use of high fidelity simulators to improve training, and some have suggested the possibility of using such high fidelity simulators to credential vascular specialties.5 ,6 More recently, sophisticated neuroendovascular simulators employing digital virtual reality have become available and pilot programs incorporating them to train neurosurgical residents have been promising.1 ,2 ,4
The core skill set required to perform neuroendovascular surgery safely and successfully is vessel selection out of the aortic arch. This study builds on our previous work using a simulator-based training environment with simple arch anatomy (type I).4 We found that even residents with little or no prior experience in cerebral angiography could become proficient at selecting vessels with a primary curve catheter. Although time to complete a procedure is not an ideal surrogate for competence and there are instances in which performing a procedure faster could reflect a more dangerous technique, in this training scenario safe technique was emphasized during the demonstration portion and each task was supervised by an experienced interventionalist.7 We therefore believe that time to complete the exercise provides a reasonable metric to detect improvement in technical skill.
The study exposed residents with a moderate exposure to vessel selection techniques to more challenging aortic anatomy to determine if the benefits of simulation training can be extended beyond straightforward anatomy to a novel challenging task requiring more advanced catheter skill sets. Residents became more proficient at vessel selection in a type II and bovine arch over a relatively compressed time period (five trials and <1 h in total), with objective data demonstrating more efficient completion of each milestone of the task. Participants also gained confidence in their skill acquisition, which was reflected in improvements in their subjective ratings of their knowledge of arch anatomy as well as vessel selection technique. Overall, participants found the exercise to be useful, the hands-on component being rated as most useful.
These findings provide preliminary data in support of a stepwise milestone-based training curricululm for neuroendovascular simulation training. To date, very few neurosurgical simulation devices have been rigorously tested with an appropriate curriculum and have demonstrated long-term benefits that warrant incorporation of such simulators in training.8 Future investigations should incorporate a higher number of participants across a broader range of backgrounds from across multiple centers in the USA. We encourage a widespread and uniform effort to build and incorporate a simulation training curriculum into formal neuroendovascular surgery training.
Footnotes
Contributors Each author made a material contribution to the article, revision of the article, and final approval of the article for submission to this journal.
Competing interests None.
Ethics approval The study was approved by the Institutional Review Board at the Medical University of South Carolina.
Provenance and peer review Not commissioned; externally peer reviewed.