Abstracts iii110 NEURO-ONCOLOGY • MAY 2017 shifting, thus not being reliable to assess whether the optimal resection rate has been achieved. One possible solution to this is the acquisition of intra- operative neuroimaging. In this original study, we evaluate the effciency of navigated ultrasound as a potential tool for acquiring intraoperative real time imaging. MATERIALS AND METHODS: Prospective study includ- ing all intracerebral tumors operated with navigated ultrasound at Sant Pau Hospital. Follow up started in July 2015 until present day. RESULTS: N = 70 patients. 38 (54,3%) female and 32 (45,7%) male. Mean age 56,3 (19-79) years. Tumors by histology: glioblastoma 22 (31,4%), metastases 18 (25,7%), low-grade glioma 7 (10%), anaplasic glioma 6 (8,5%), anaplasic oligodendroglioma 5 (7,1%), oligodendroglioma 4 (5,7%), gliosarcoma 2 (2,8%), cavernoma 2 (2,8%), lymphoma 1 (1,4%), pilocytic astrocitoma 1 (1,4%), nonspecifc infammation 1 (1,4%) and demyelinating disease 1 (3%). All lesions were classifed according to the ultrasonographic visibility scale, described in the literature: Grade 3: Lesion clearly identifable and clear border with normal tissue, Grade 2: Lesion clearly identifable but no clear border with normal tissue, Grade 1: Lesion diffcult to visualize and no clear border with normal tissue and Grade 0: Lesion not visible. Of all included cases, 51 (72,8%) where Grade 3 tumors, 16 (22,8%) Grade 2, 2 (2,8%) Grade 1 and 1 (1,4%) Grade 0. Interestingly, the most frequently operated intracranial lesions (metastases and glioblastoma) present a high degree of adequate intraoperative visualization with a mean 94,4% Grade 3 for metastases and 77,2% for glioblastoma. Despite being regularly visual- ized, low-grade gliomas tend to show blurred margins, presenting on our series with a 54,5% Grade 3 and 57,1% grade 2. We need to consider the infltrative nature of low-grade gliomas when interpreting these results. On 11 (15,7%) of all cases, the navigated ultrasound provided imaging informa- tion to lead to further tumor resection. On 5 (7,1%) of all cases, a Doppler study was performed to assess vascular permeability. There were no com- plications associated to the use of navigated ultrasound. CONCLUSIONS: Navigated ultrasound is an effective, economic and secure technique that provides good quality real-time intraoperative images. P16.04 PRACTICAL APPLICATION OF INTRAOPERATIVE TRACTOGRAPHY ON AWAKE BRAIN SURGERY C. de Quintana Schmidt 1 , A. Leidinger 1 , B. Gomez 2 , E. Granell 2 , O. Gallego 3 , J. Craven 4 , L. Salgado 1 , M. Rico 1 , J. Aibar 1 , J. Molet 1 ; 1 Neurosurgery Department, Sant Pau Hospital, Barcelona, Spain., Barcelona, Spain, 2 Neuroradiology Department, Sant Pau Hospital, Barcelona, Spain., Barcelona, Spain, 3 Oncology Department, Sant Pau Hospital, Barcelona, Spain., Barcelona, Spain, 4 Radiotherapy Department, Sant Pau Hospital, Barcelona, Spain., Barcelona, Spain. INTRODUCTION: Tractography is a radiological technique which allows a non-invasive understanding of subcortical brain fber tracts. It is a helpfull technique for presurgical planning and the study of tumoral lesions and their anatomical relationship with adjacent fbers. However, there is an open debate on inter-observer variability, limits in lesion with edema for example, ultimate precision, and its practical beneft during surgery. In our study we analyze the practical beneft of intraoperative tractography in awake brain surgery MATERIALS AND METHODS: Prospective study using intraoperative trac- tography on awake surgery patients at Sant Pau Hospital. Follow up started in 2014 until present day. We compare awake patient surgeries with and without the use of intraoperative tractography after the acquisition of a navigation system that allowed us to apply this technique. Studied variables: surgical time with awake patient in minutes (using the asleep-awake-asleep technique), pain (VAS scale), anxiety (0-10), degree of collaboration (0-10 being 10 maxi- mum punctuation) and percentage of complete resection. RESULTS: N= 36 patients. 25 male (69,4%) and 11 female (30,6%). Mean age: 53,8 (33-75) years. Awake surgery with intraoperative tractography was performed on 19 patients [52,8% IC95% 36,5-69,1%]. On 17 patients, this technique was no available [47,2% IC95% 30,9-63,5%]. Mean surgical time on the trac- tography group was of 93,6 minutes, versus 119,8 minutes for those awake patient surgery without the use of this tool. Mean surgical time reduction was of 26,1 minutes [IC95% 9,3-43 minutes] (p=0.004). The mean degree of patient collaboration scored 7,4 when using intraoperative tractography, versus 6,8 when not, mean pain scores were of 2,6 versus 3 and mean anxiety score of 3,3 versus 3,2 (p=0.403, p=0.394 y p=0.889 respectively). 73,7% of the patients operated with intraoperative tractography had total resec- tions, against 52,9% for those without this tool. (p=0.299). CONCLUSIONS: Intraoperative tractography aids the surgeon reducing the duration of awake patient surgeries, although there is no statistically signifcant repercussion on intraoperative anxiety or pain scores, nor on the degree of collaboration dur- ing the procedure. It seems that a higher rate of full resections is obtained when using intraoperative tractography, despite no statistical signifcance. P16.05 PERCUTANEOUS VERTEBRAL BODY STENTING TO RESTORE STABILITY OF THE ANTERIOR COLUMN IN EXTREME SPINAL OSTEOLYSIS A. Cianfoni 1 , D. Distefano 1 , V. Espeli 2 , G. Bonaldi 3 , P. Scarone 4 , G. Pesce 2 ; 1 Department of Neuroradiology, Neurocenter of Southern Switzerland, Lugano, Switzerland, 2 Oncology Institute of Southern Switzerland, Bellinzona, Switzerland, 3 Department of Neuroradiology, Bergamo, Italy, 4 Departement of Neurosurgery, Neurocenter of Southern Switzerland, Lugano, Switzerland. INTRODUCTION: Extreme neoplastic osteolysis of the vertebral body (VB) determines risk of collapse and instability. The current treatment of extensive VB lesions aims to restore stability with instrumentation gener- ally performed with a combined, anterior and posterior, surgical approach. The anterior part of this operation carries signifcant morbidity related to its invasiveness, long hospitalization and high complication rate. Percutane- ous vertebral augmentation is a palliative treatment of painful or at-risk of- collapse lytic VB lesions, but osteolysis with wide cortical involvement has higher risk of cement leakage, possibly limiting the amount of cement injected, resulting in insuffcient stabilization. Vertebral body stent (VBS) is a barrel-shaped semi-rigid implant with large support surface, that can be inserted with a percutaneous image-guided minimally invasive technique, and allows primary stabilization of anterior column and cement contain- ment. The aim of our work was to assess technical and clinical results and complications of a procedure of kyphoplasty with VBS for pain palliation and spinal stabilization in selected patients with extreme lytic VB lesions. MATERIALS AND METHODS: retrospective review of a prospectively maintained database of 29 consecutive patients with extensive neoplastic osteolysis (>2/3 of the VB with erosion of the cortical boundaries) in one or more VB, from T1 to S1, for a total of 42 spinal levels, treated with kyphoplasty and VBS between March 2013 and September 2016. All target lesions presented morphological criteria of instability based on SINS and/ or Taneichi criteria. Post-procedural CT images were reviewed in consensus by two neuroradiologists and one neurosurgeon to assess the correct place- ment of the devices and the cement flling of the lytic cavities, to evaluate the results in terms of restoration of VB height, stabilization of the target level, and to detect technical complication. Clinical and radiological follow- up was performed at 30 days and patients were followed up clinically and radiologically as per oncology clinical practice. Follow-up ranges between 1 and 24 months. RESULTS: The procedure was deemed technically successful in providing structural stability in 40/42 cases. Epidural or foraminal leaks of cement occurred in 5/42 levels without clinical consequences. In 1 case there was an anterior mobilization of the stents with onset of dysphagia, at 30 days, that gradually resolved, with no further implant mobilization at 3 months. Pain reduction was attributable to the procedure itself in 19 cases, in combination with radiation and/or chemotherapy in 6, while 4 patients reported no signifcant pain amelioration. CONCLUSIONS: Our prelimi- nary results support the use of kyphoplasty with VBS as an effective and safe procedure to restore stability and reduce pain in selected patients with extreme spinal osteolysis. P16.06 MANAGEMENT AND LONG TERM OUTCOME OF INTRACRANIAL SUBEPENDYMOMA D. Giraldi 1 , A. Varma 2 , A. R. Brodbelt 1 , M. D. Jenkinson 1 ; 1 The Walton Centre, Liverpool, United Kingdom, 2 University of Liverpool, Liverpool, United Kingdom. INTRODUCTION: Intracranial subependymoma (WHO grade 1) account for 0.2-0.7% of all central nervous system (CNS) tumours. They are intraventricular tumours and present as incidental fndings or cause hydrocephalus. The study aim was to evaluate the management and outcome following surgical resection of subependymoma. MATERIALS AND METHODS: Retrospective, single centre case note review in adults with WHO grade 1 subependymoma diagnosed between 1990-2015. Ependymomas and subependymal giant cell astrocytomas were excluded. Tumour location, extent of resection (defned as gross total resection (GTR), sub-total resection (STR) or biopsy) and the WHO performance status (PS) were recorded at time of presentation and at follow- up. RESULTS: 13 patients (7 male; 6 female) with a mean age of 47.6 years (range 33-58 years) were included. Mean follow-up was 62.7 months (range 24-216). 5 patients had incidental fndings; 8 patients had sympto- matic tumours (headache, cerebellar ataxia, cranial nerves defcits). PS at diagnosis was 0 (n=8) and 1 (n=5). Tumours were located in the 4 th (n=9), lateral (n=2 left, n=2 right) and 3 rd ventricle (n=1). 12 patients underwent craniotomy for excision (GTR n=11; STR n=1) and 1 craniectomy for co- existing Chiari Malformation (biopsy n=1). Early post- operative PS was 0 (n=3) and 1 (n=10). At last follow-up PS was 0 (n=11) and 1 (n=2). 2 patients developed symptomatic post-operative hydrocephalus (13.3%) and required ventriculoperitoneal shunt. There was no recurrence fol- lowing GTR, and no growth following STR or biopsy. Only 2 patients, remains in PS 1 at last follow- up, while 84.6% are symptom free and PS 0. CONCLUSIONS: Typical neuroradiology appearance is diagnostic of subependymoma. When diagnosis is secure subependymoma are known to be indolent tumours. Whilst modern neurosurgery is safer, surgical resec- tion should be restricted to those with symptomatic tumours given the risk of post-operative hydrocephalus. Incidental subependymoma could be fol- lowed with surveillance MRI without the need for surgery. Downloaded from https://academic.oup.com/neuro-oncology/article/19/suppl_3/iii110/3744224 by guest on 09 December 2021