The impact of auditory feedback on neuronavigation

Object. We aimed to develop an auditory feedback system to be used in addition to regular neuronavigation, in an attempt to improve the usefulness of the information offered by neuronavigation systems. Instrumentation. Using a serial connection, instrument co-ordinates determined by a commercially available neuronavigation system were transferred to a laptop computer. Based on preoperative segmentation of the images, the software on the laptop computer produced an audible signal whenever the instrument moved into an area the surgeon wanted to avoid. Methods. To evaluate the impact of our setup on volumetric resections, phantom experiments were conducted. CT scans were acquired from eight blocks of floral foam. In each of these scans, a target-volume was segmented. This target-volume was subsequently resected using either regular neuronavigation or neuronavigation extended with auditory feedback. A 'postoperative' CT scan was used to compare the resection cavity to the preoperatively planned target-volume. Findings. The resemblance between the resection cavity and the target-volume was greater each time auditory feedback had been used. This corresponded with more complete removal of the target-volume. However, it also corresponded with the removal of more non-target 'tissue' in two out of four cases. Conclusions. The usefulness of auditory feedback was made plausible and the use of a new type of navigation phantom was illustrated. Based on these results, we recommend incorporation of auditory feedback, in commercially available neuronavigation systems, especially since this is relatively inexpensive