Development Of Epidural Simulators: Towards Hybrid Virtual Reality Training
Over 1000 epidurals are performed in the UK daily and the procedure consists of an 8cm long needle being inserted in the lumbar spine. It is a difficult procedure, which leads to 2.8% of patients being injured in procedural mistakes, including permanent neurological damage, paralysis and rarely death. Epidural simulators aim to provide a safe and controlled environment for novices to learn epidural procedure. This Chapter provides an overview of epidural simulation and a background on the use of simulators for training. A review is provided covering the use and development of epidural simulators. In total 34 epidural or lumbar puncture simulators have been developed since 1980, each enables epidural practice utilising a variety of mechanisms and technologies. Epidural simulators can be generally grouped into two categories; manikin based and computer based simulators. Currently there are no commercially available epidural simulators that use virtual reality (VR) as the guiding principle for training; only manikin based models are commonly used. The benefits of both are discussed and compared. Virtual reality simulation allows epidural skills to be objectively quantified for assessment by themeasurement of skill parameters. Virtual reality simulations improve hand-eye coordination, spatial visualization, manual dexterity, and rapid mental processing, which are important in the acquisition of epidural insertion skills. Warm-up training in a virtual reality simulator improves epidural performance for various experience levels. The overall aim is to improve epidural training, reduce cost of litigation to health services and reduce risk of injury to patients. Patient-specific virtual reality concepts can be applied to model epidural needle insertion on any size of patient. This allows training for any body-fat composition especially to target the obesity epidemic which increases the difficulty of epidural procedures. Patient specific simulation can be achieved with accurate haptic feedback which adapts to patient's Body Mass Index (BMI) variations. A novel haptic virtual reality based epidural training simulator was developed which is briefly covered in this Chapter. The simulator is a mixed augmented device containing a physical manikin together with virtual reality underlays based on 3D computer models. Our virtual hybrid simulator allows epiduralists to practice needle insertions viewing virtual reality based anatomic models in stereo whilst their hands manipulate the needle on a physical model. Accurate haptic feedback is based on the clinical trial which measured in-vivo epidural insertion pressures during needle insertion from obstetric patients.Combinations of Magnetic Resonance Images (MRI) and ultrasound images from actual patients are included for various BMIs together with a neural network model to calculate body shape and size from measured data of over 23000 actual patients.