Virtual reality cerebral aneurysm clipping simulation with real-time haptic feedback

Abstract

Background: With the decrease in the number of cerebral aneurysms treated surgically and the increase of complexity of those treated surgically, there is a need for simulation-based tools to teach future neurosurgeons the operative techniques of aneurysm clipping.

Objective: To develop and evaluate the usefulness of a new haptic-based virtual reality simulator in the training of neurosurgical residents.

Methods: A real-time sensory haptic feedback virtual reality aneurysm clipping simulator was developed using the ImmersiveTouch platform. A prototype middle cerebral artery aneurysm simulation was created from a computed tomographic angiogram. Aneurysm and vessel volume deformation and haptic feedback are provided in a 3-dimensional immersive virtual reality environment. Intraoperative aneurysm rupture was also simulated. Seventeen neurosurgery residents from 3 residency programs tested the simulator and provided feedback on its usefulness and resemblance to real aneurysm clipping surgery.

Results: Residents thought that the simulation would be useful in preparing for real-life surgery. About two-thirds of the residents thought that the 3-dimensional immersive anatomic details provided a close resemblance to real operative anatomy and accurate guidance for deciding surgical approaches. They thought the simulation was useful for preoperative surgical rehearsal and neurosurgical training. A third of the residents thought that the technology in its current form provided realistic haptic feedback for aneurysm surgery.

Conclusion: Neurosurgical residents thought that the novel immersive VR simulator is helpful in their training, especially because they do not get a chance to perform aneurysm clippings until late in their residency programs.

Figure 1

A general view of the immersive virtual reality environment being used by a resident. The operator is using haptic devices in both right and left hand which mimic the operating room environment. The virtual image is projected on a screen in front of the resident.

Figure 2

3-D stereoscopic immersive virtual reality model of the skull and head for middle cerebral artery (MCA) aneurysm clipping simulation, based on patient-specific CTA. A. The operator designs the craniotomy for the best surgical approach. B. View after the craniotomy is created and the dura opened. Frontal and temporal lobes are separate volumes that can be retracted independently. C. Virtual head model with skin flap raised and lifted anteriorly. The operator grasps the haptic device stylus, which appears in the VR space as an aneurysm clip holder. The aneurysm clip is suspended in space. D. The operator grasps the clip with the clip holder. This provides a test of 3-D depth perception.

Figure 3

Virtual clipping of patient-specific MCA aneurysm. A. Translucent representation of brain parenchyma reveals the position of the proximal M1 and distal M2 branches within a partially opened sylvian fissure; clip is applied for reference purposes. B. Same view as A with opaque parenchyma shows the M1 to be hidden under the temporal lobe. C. Sufficient visualization of the M1, aneurysm neck, and M2 branches is achieved by greater separation of frontal and temporal lobes. This was the view presented to the neurosurgery residents. D. The operator uses the side of the aneurysm clip to retract aneurysm dome in real time, with sensory haptic feedback. E. The operator presses on the haptic stylus, representing the virtual clip applier, to open the aneurysm clip blades. As the clip is applied across the neck, it produces real deformation of the aneurysm. F. The aneurysm clip is released across the neck and the blades close, causing the aneurysm to deform and collapse. Proximal M1 and distal M2 branches appear to be patent.

Figure 4

The virtual suction tip removes blood from simulated aneurysm rupture. The tool can also be used to retract the brain.

Figure 5

The result of the residents’ assessment, which was based on 5-point Likert scales where 5 represents the highest rank and 1 represents the lowest rank.