Initial experience with navigated intraoperative ultrasound for brain tumour surgery

AbstractAimsThe use of intraoperative ultrasound (iUS) has been associated with prolonged survival in patients with high grade glioma. However, iUS remains an under-utilised surgical adjunct in many neurosurgical units due to greater familiarity with CT and MR imaging. Navigated intraoperative ultrasound (NiUS) facilitates co-registration of pre-operative MR imaging with iUS, offering a number of advantages over standard neuronavigation. The aim of this study was to describe our initial experiences with NiUS for brain tumour resection in adults.MethodWe prospectively collected data on patient demographics, tumour location and histology, extent of resection and early post-operative outcome in 9 consecutive patients. Brainlab neuronavigation (BrainLab, Germany) and the BK5000 cranial ultrasound probe (BK Medical, Denmark) were used in all cases. We also collected data on surgical intent and the use of surgical adjuncts including neurophysiology monitoring, DTI and 5ALA.ResultsNiUS was used in 9 patients (6 male, 3 female). iUS scans were successfully co-registered in all cases. Histological diagnoses were GBM (7 patients), melanoma (1 patient) and oligodendroglioma (1 patient). NiUS was used in conjunction with the following techniques and adjuncts – awake craniotomy (2), DTI (all cases), neurophysiology monitoring (4 cases) and 5ALA (7 cases). Gross total resection was achieved in 8 patients. The mean operative time was 4 hours and 7 minutes, which is significantly lower than that reported in a recently published series involving intra-operative MRI. No patients suffered any deterioration in neurological status in the early post-operative period.ConclusionNiUS was rapidly assimilated into our surgical workflow with successful co-registration in all cases. NiUS was used successfully in conjunction with awake craniotomy, neurophysiology monitoring, DTI and 5ALA for both enhancing and non-enhancing tumours. Based on our early experience we offer learning points on patient positioning, set up of equipment and interpretation of iUS. Further studies are required to determine the impact of NiUS on patient outcome.