Validation of exposure visualization and audible distance emission for navigated temporal bone drilling in phantoms

BACKGROUND: A neuronavigation interface with extended function as compared with current systems was developed to aid during temporal bone surgery. The interface, named EVADE, updates the prior anatomical image and visualizes the bone drilling process virtually in real-time without need for intra-operative imaging. Furthermore, EVADE continuously calculates the distance from the drill tip to segmented temporal bone critical structures (e.g. the sigmoid sinus and facial nerve) and produces audiovisual warnings if the surgeon drills in too close vicinity. The aim of this study was to evaluate the accuracy and surgical utility of EVADE in physical phantoms. METHODOLOGY/PRINCIPAL FINDINGS: We performed 228 measurements assessing the position accuracy of tracking a navigated drill in the operating theatre. A mean target registration error of 1.33±0.61 mm with a maximum error of 3.04 mm was found. Five neurosurgeons each drilled two temporal bone phantoms, once using EVADE, and once using a standard neuronavigation interface. While using standard neuronavigation the surgeons damaged three modeled temporal bone critical structures. No structure was hit by surgeons utilizing EVADE. Surgeons felt better orientated and thought they had improved tumor exposure with EVADE. Furthermore, we compared the distances between surface meshes of the virtual drill cavities created by EVADE to actual drill cavities: average maximum errors of 2.54±0.49 mm and -2.70±0.48 mm were found. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that EVADE gives accurate feedback which reduces risks of harming modeled critical structures compared to a standard neuronavigation interface during temporal bone phantom drilling

Parkinsonism and dementia are negative prognostic factors for the outcome of subdural hematoma

To determine, among a population with subdural hematoma (SH), whether patients affected by neurodegenerative disorders (parkinsonism and dementia) have a worse clinical outcome. We reviewed the data of patients diagnosed with fall-related SH discharged from the Departments of Neurology/Stroke unit, Neurosurgery, Intensive Care Unit at Brotzu General Hospital (Cagliari, Italy) between January 2010 and December 2013. Patients with severe traumatisms, evidence of spontaneous intracerebral bleeding or aged less than 50 were excluded. 332 patients were selected: 69 with a neurodegenerative parkinsonism or dementia (N-group), 217 with history of chronic non-neurological medical conditions with significant disability, previous falls and/or balance problems (NND-group) and 46 with a history of "minor" chronic non-neurological disorder. (NN-group). The clinical status at admission and discharge was assessed by modified Rankin Scale (mRS). The time-span between trauma and hospital admission was also calculated. At hospital admission we found a significantly longer delay in SH's diagnosis (χ (2) test p < 0.001) and a worse mRS score (Kruskal Wallis p < 0.001) in the N-group compared to both NN and NND-groups. During hospital stay we observed the lack of significant variation in mRS score in N-group (Wilcoxon test p = 0.86), in contrast with NN and NND-groups who significantly improved (Wilcoxon test p < 0.001). Our results demonstrate that the consequences of SH are more severe in the N-group compared to NN and NND-groups. The longer interval between trauma and hospital admittance plays a critical role in worsening the outcome of patients with parkinsonism and dementia compared to subjects without neurodegenerative disorder