Design of an interactive lumbar puncture simulator with tactile feedback

Lumbar puncture for purposes of administering spinal or epidural anesthesia is a complex clinical skill which requires the clinician to precisely correlate a detailed mental map of hidden three-dimensional anatomy with tactile feedback from the spinal needle as it is inserted. To be successful the trainee must create a mental map of the anatomy by integrating atlas illustrations with bony and/or surface landmarks. The placement of the needle must then be guided by the continuous correlation of this mental map and the tactile feedback, or "feel," of the needle as it is being inserted. The simulator consists of a combination of specialized hardware and custom software running on a high-resolution graphics workstation. The major piece of specialized hardware is the force-feedback needle simulator. This is a specialized joystick which resembles a long, thin pen or wand swivel-mounted to a vertical face of a box roughly 12 inches on a side. Position sensors track the insertion angle or trajectory of the device while a programmable motor or actuator will provide variable resistance to insertion depending upon which simulated anatomic structures the virtual needle is penetrating. If an incorrect trajectory is used and bone is contacted the resulting sudden sharp increase in resistance would be conveyed