Pilot study – A haptic-based virtual reality neurosurgery simulator

Conclusions

An expert neurosurgeon adjusted the characteristics of the anatomical structures to the characteristics of the real tissues. Then, the expert assessed the realism of the 3D models and haptic interaction.

Introduction

Pérez-Pachón L1, Poyade M 2, Brown J 3, Fallon V 4

1 University of Aberdeen, School of Medicine, Medical Sciences and Nutrition 2 University of Glasgow, Glasgow School of Art, Digital Design Studio3 Institute of Neurological Sciences, Queen Elizabeth University Hospital, Glasgow 4 University of Glasgow, School of Medicine

3D anatomical structures were modelled from MRI scans using segmentation algorithms and modelling software.

A virtual patient, frame and biopsy needle were added

to the simulator, which includes controls to adjust

the characteristics of the anatomical tissues.

The 3D models were embedded in a virtual

environment where the user can explore the anatomical structures and learn about

the procedure.

These characteristics can be felt by the user when piercing the tissues with the needle. The latest can be manipulated by using a haptic device.

A trajectory was created for interaction with the haptic device.

Methodology & Development

The mapping of the biopsy needle is affected by the low accuracy of the current haptic device.

The density, boundary characteristics, shape and texture of the anatomical structures are correct.

The insertion of the biopsy needle is more complex than anticipated compared to an actual operative environment.

This tool is a part-task trainer which allows trainee surgeons to practice inserting a needle into a patient’s brain and collecting viable tissue samples in a simulated environment.

Further steps include improvement of the haptic interaction and mapping of the needle, and inclusion of the currently missing procedural steps. In addition, stereoscopy would greatly assist the user in guiding the needle across the 3D space. Finally, validation of the tool would be necessary for its implementation in the training curricula.

Current neurosurgical training methods rely on “hands on” skills acquisition in the operating theatre. 

However, haptic-based virtual reality simulators can recreate the perceptual experience of surgical procedures by simulating the tactile properties of tissues and surgical instrumentation. This in turn, enables the “surgeon in training” to acquire surgical skills in a safe virtual learning environment.

A frame-based stereotactic brain biopsy is a surgical procedure where samples of a brain tissue are extracted for examination. A stereotactic frame is attached to the patient’s head and a CT scan is performed. The stereotactic coordinates of the target tissue are calculated and registered onto the frame which guides the biopsy needle into the target tissue in the planned trajectory.

This pilot study has seen the creation of a prototype haptic-based virtual reality simulator which, with further development, may complement traditional neurosurgery training in stereotactic brain biopsies.

Parameterization & Evaluation

The authors acknowledge the patients for their permission to use clinical data. We thank Daniel Livingstone and the staff at the Digital Design Studio for their technical assistance, and Patricia Littlechild at the Queen Elizabeth University Hospital for her assistance with scanning and image guidance.

Acknowledgements

Some steps are currently missing in the simulation, such as the rotation and depth readjustment of the needle, or the use of a syringe.

The surgical instruments are accurate.