Development of a pin-less reference head frame: An experimental setup and preliminary experiences

Abstract

Objectives: Advantages of image guidance in neurosurgical procedures are undisputed. Although some approaches of flexible technologies already exist, today's gold standard for neuronavigation is the pin-assisted head clamp fixation. A reference tool that is simpler in handling, universally available and non-invasive would be desirable. We introduce two pin-less mobile head frames and investigate their feasibility in a series of exercises. Patients and methods: A head frame, which is originally used as facebow in dentistry, was modified to create 2 head frames. A sequence of exercises was designed to imitate the different movements of a patients head in a real case of emergency. The trial was subdivided in two phases each with 10 healthy participants. The requirement to each participant was to complete the sequence of exercises whilst wearing the frame. Different parameters were collected. Results: The frame-to-head stability was not sufficient for the first frame. It increased significantly for the second frame, mainly due to the flexible forehead- and the occiput-band. The handling of both devices was cumbersome and time-consuming. Conclusion: The sequence of exercises proved to be a suitable approach to investigate the advantages and disadvantages of the frames. The presented devices are not acceptable for emergency clinical practice yet. Further modification is necessary. Invasive pins are not mandatory for a close fit of the frame. The presented trial is superior to the investigation using an immobile skull model. Keywords: Neuronavigation, Reference tool, Frame, Clamp, Pin-less, Non-invasive