PP21. AWAKE CRANIOTOMY FOR RESECTION OF BRAIN TUMOURS: SURVEY OF THE UNITED KINGDOM PRACTICE IN 2015

Abstract

ABSTRACT: Awake craniotomy (AC) is a useful surgical technique to help identify and preserve eloquent areas during cortical and subcortical tumour resections. Here the UK practice of AC in 2015 is reviewed. MATERIAL AND METHODS: An online survey (SurveyMonkey LTD) supported by the British Neuro-Oncology Society (BNOS) regarding AC practice was sent to a neurosurgical consultant with a specialist interest in oncology at all thirty neurosurgical centres in the UK. RESULTS: 100% of units responded to the survey. 27/30 UK neurosurgical units performed AC in 2015. 575 AC were performed by 60 neurosurgical consultants (range 1–4, median 2 per unit). 87 anaesthetic consultants routinely covered AC lists (range 1–6, median 3 per unit). A general anaesthetic/ awake/ general anaesthetic or awake technique was performed in 18 units, while conscious sedation/awake /conscious sedation was performed in 14 units. Dexmedetomidine and Remifentanil were the favoured agents used in 6 units with the rest using Propofol and Remifentanil. Depending on patient factors AC was performed purely under local anaesthetic in 10 units. All neurosurgical units would consider AC for resection of low grade glioma (LGG), 20 units for high grade glioma (HGG), 10 units for metastases, 8 units for epilepsy and 3 units for some vascular indications. Less than half of units use DTI for tractography or fMRI for language localisation. Bipolar stimulation for direct cortical and subcortical mapping was used in 26 units; monopolar stimulation alone was used in 1 unit and both modalities of stimulation were used in 7 units. A third of units routinely measured motor evoked potentials and somatosensory evoked potentials during AC and a quarter routinely measured after discharges. Intra-operative neuropsychological paradigms were tested by either a speech and language specialist (16 units) or neuropsychologist (12 units) and in 4 units, paradigms were routinely tested by the anaesthetic team or nursing staff. Paradigm testing was performed in conjunction with direct cortical or subcortical stimulation and during resective surgery. A post operative MRI head within 48 hours was routinely performed at 22 units, and day case AC was offered at 3 units. DISCUSSION: This is a unique snapshot of how AC was performed predominantly for tumour resection in eloquent cortex in 2015 in the UK. Since 2008 there has been an increase in the number of UK units from 19 to 27 offering AC, and the number of consultant anaesthestists being involved with cases has almost doubled (1). AC is predominantly used and reported for resection of LGG (2). However in our study, 75% of units would consider AC for HGG. With the increasing use of AC by dedicated teams using different techniques, this offers a valuable opportunity to compare results, optimise safety, improve techniques and potentially provide a more unified approach allowing national collaboration.