Prognosis versus Actual Outcomes in Stereotactic Radiosurgery of Brain Metastases: Reliability of Common Prognostic Parameters and Indices

This study aims to evaluate the clinical outcome of stereotactic radiosurgery as the sole treatment for brain metastases and to assess prognostic factors influencing survival. A total of 108 consecutive patients with 213 metastases were retrospectively analyzed. Treatment was determined with close-meshed MRI follow-up. Various prognostic factors were assessed, and several prognostic indices were compared regarding their reliability to estimate overall survival. Median overall survival was 15 months; one-year overall survival was 50.5%. Both one- and two-year local controls were 90.9%. The rate of new metastases after SRS was 49.1%. Multivariate analysis of prognostic factors revealed that the presence of extracranial metastases, male sex, lower KPI, and progressive extracranial disease were significant risk factors for decreased survival. Of all evaluated prognostic indices, the Basic Score for Brain Metastases (BSBMs) showed the best correlation with overall survival. A substantial survival advantage was found for female patients after SRS when compared to male patients (18 versus 9 months, p = 0.003). SRS of brain metastasis is a safe and effective treatment option when frequent monitoring for new metastases with MRI is performed. Common prognostic scores lack reliable estimation of survival times. Female sex should be considered as an additional independent positive prognostic factor influencing survival.

Cadaveric study of ergonomics and performance using a robotic exoscope with a head-mounted display in spine surgery

The conventional microscope has the disadvantage of a potentially unergonomic posture for the surgeon, which can affect performance. Monitor-based exoscopes could provide a more ergonomic posture, as already shown in pre-clinical studies. The aim of this study was to test the usability and comfort of a novel head-mounted display (HMD)-based exoscope on spinal surgical approaches in a simulated OR setting. A total of 21 neurosurgeons naïve to the device were participated in this prospective trial. After a standardized training session with the device, participants were asked to perform a single-level thoracolumbar decompression surgery on human cadavers using the exoscope. Subsequently, all participants completed a comfort and safety questionnaire. For the objective evaluation of the performance, all interventions were videotaped and analyzed. Twelve men and nine women with a mean age of 34 (range: 24-57) were participating in the study. Average time for decompression was 15 min (IqR 9.6; 24.2); three participants (14%) terminated the procedure prematurely. In these dropouts, a significantly higher incidence of back/neck pain (p = 0.002 for back, p = 0.046 for neck pain) as well as an increased frequency of HMD readjustments (p = 0.045) and decreased depth perception (p = 0.03) were documented. Overall, the surgeons' satisfaction with the exoscope was 84% (IqR 75; 100). Using a standardized, pre-interventional training, it is possible for exoscope-naïve surgeons to perform sufficient spinal decompression using the HMD-based exoscope with a high satisfaction. However, inaccurate HMD setup prior to the start of the procedure may lead to discomfort and unsatisfactory results.

Tumor Location Impacts the Development of Radiation Necrosis in Benign Intracranial Tumors

BACKGROUND

Radiation necrosis (RN) is a possible late complication of stereotactic radiosurgery (SRS), but only a few risk factors are known. The aim of this study was to assess tumor location in correlation to the development of radiation necrosis for skull base (SB) and non-skull base tumors.

METHODS

All patients treated with radiosurgery for benign neoplasms (2004-2020) were retrospectively evaluated. The clinical, imaging and medication data were obtained and the largest axial tumor diameter was determined using MRI scans in T1-weighted imaging with gadolinium. The diagnosis of RN was established using imaging parameters. Patients with tumors located at the skull base were compared to patients with tumors in non-skull base locations.

RESULTS

205 patients could be included. Overall, 157 tumors (76.6%) were located at the SB and compared to 48 (23.4%) non-SB tumors. Among SB tumors, the most common were vestibular schwannomas (125 cases) and meningiomas (21 cases). In total, 32 (15.6%) patients developed RN after a median of 10 (IqR 5-12) months. Moreover, 62 patients (30.2%) had already undergone at least one surgical resection. In multivariate Cox regression, SB tumors showed a significantly lower risk of radiation necrosis with a Hazard Ratio (HR) of 0.252, p < 0.001, independently of the applied radiation dose. Furthermore, higher radiation doses had a significant impact on the occurrence of RN (HR 1.372, p = 0.002).

CONCLUSIONS

The risk for the development of RN for SB tumors appears to be low but should not be underestimated. No difference was found between recurrent tumors and newly diagnosed tumors, which may support the value of radiosurgical treatment for patients with recurrent SB tumors.

A randomized, single ascending dose safety, tolerability and pharmacokinetics study of NicaPlant® in aneurysmal subarachnoid hemorrhage patients undergoing clipping

Introduction

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high morbidity and mortality. Post-hemorrhagic vasospasm with neurological deterioration is a major concern in this context. NicaPlant®, a modified release formulation of the calcium channel blocker nicardipine, has shown vasodilator efficacy preclinically and a similar formulation known as NPRI has shown anti-vasospasm activity in aSAH patients under compassionate use.

Research question

The study aimed to assess pharmacokinetics and pharmacodynamics of NicaPlant® pellets to prevent vasospasm after clip ligation in aSAH.

Material and methods

In this multicenter, controlled, randomized, dose escalation trial we assessed the safety and tolerability of NicaPlant®. aSAH patients treated by clipping were randomized to receive up to 13 NicaPlant® implants, similarly to the dose of NPRIs previous used, or standard of care treatment.

Results

Ten patients across four dose groups were treated with NicaPlant® (3-13 implants) while four patients received standard of care. 45 non-serious and 13 serious adverse events were reported, 4 non-serious adverse events and 5 serious adverse events assessed a probable or possible causal relationship to the investigational medical product. Across the NicaPlant® groups there was 1 case of moderate vasospasm, while in the standard of care group there were 2 cases of severe vasospasm.

Discussion and conclusion

The placement of NicaPlant® during clip ligation of a ruptured cerebral aneurysm raised no safety concern. The dose of 10 NicaPlant® implants was selected for further clinical studies.

Somatostatin receptor subtype expression and radiomics from DWI-MRI represent SUV of [68Ga]Ga-DOTATOC PET in patients with meningioma

OBJECTIVE

This retrospective study aimed to analyse the correlation between somatostatin receptor subtypes (SSTR 1-5) and maximum standardized uptake value (SUVmax) in meningioma patients using Gallium-68 DOTA-D-Phe1-Tyr3-octreotide Positron Emission Tomography ([68Ga]Ga-DOTATOC PET). Secondly, we developed a radiomic model based on apparent diffusion coefficient (ADC) maps derived from diffusion weighted magnetic resonance images (DWI MRI) to reproduce SUVmax.

METHOD

The study included 51 patients who underwent MRI and [68Ga]Ga-DOTATOC PET before meningioma surgery. SUVmax values were quantified from PET images and tumour areas were segmented on post-contrast T1-weighted MRI and mapped to ADC maps. A total of 1940 radiomic features were extracted from the tumour area on each ADC map. A random forest regression model was trained to predict SUVmax and the model's performance was evaluated using repeated nested cross-validation. The expression of SSTR subtypes was quantified in 18 surgical specimens and compared to SUVmax values.

RESULTS

The random forest regression model successfully predicted SUVmax values with a significant correlation observed in all 100 repeats (p < 0.05). The mean Pearson's r was 0.42 ± 0.07 SD, and the root mean square error (RMSE) was 28.46 ± 0.16. SSTR subtypes 2A, 2B, and 5 showed significant correlations with SUVmax values (p < 0.001, R2 = 0.669; p = 0.001, R2 = 0.393; and p = 0.012, R2 = 0.235, respectively).

CONCLUSION

SSTR subtypes 2A, 2B, and 5 correlated significantly with SUVmax in meningioma patients. The developed radiomic model based on ADC maps effectively reproduces SUVmax using [68Ga]Ga-DOTATOC PET.

Temporal muscle thickness has no prognostic relevance in patients with high-grade glioma compared to functional scales

Background

GBM research is constantly assessing potential valuable prognostic biomarkers to better understand the disease and prognosticate future outcomes. Measuring temporal muscle thickness (TMT) has appeared to be a promising new surrogate marker for skeletal muscle mass and sarcopenia, which further indicates frailty and predicts overall survival (OS). The aim of this study was to determine its usefulness as a prognostic marker in patients with high-grade glioma compared to functional status scales.

Methods

TMT was measured in preoperative axial T1-weighted contrast-enhanced magnetic resonance images in 277 patients who received surgical treatment of newly diagnosed WHO III and IV gliomas in our institution between 2015 and 2020. Clinical Frailty Scale (CFS) and Karnofsky Performance Scale (KPS) were assessed preoperatively and during a follow-up visit.

Results

Female gender has shown significant correlation with TMT, while TMT did not correlate with preoperative and follow-up functional scores, age, WHO classification, IDH mutation, MGMT promoter methylation, EGFR and ATRX expression, or 1p/19q co-deletion. No significant prognostic value of TMT could be shown in 6, 12, and 24 months OS, while changes in CFS and KPS proved to have a significant impact.

Conclusion

Only female gender, but no other clinical, histological, or molecular marker showed any interrelation with TMT. Functional scores outclass measuring TMT as a reliable prognostic factor for predicting OS in patients with high-grade glioma.

Same but different. Incidental and symptomatic lower grade gliomas show differences in molecular features and survival

PURPOSE

Data on differences in overall survival and molecular characteristics between incidental (iLGG) and symptomatic lower grade Glioma (sLGG) are limited. The aim of this study was to investigate differences between patients with iLGG and sLGG.

METHODS

All adult patients with a histologically proven diffuse (WHO°II) or anaplastic (WHO°III) glioma who underwent their first surgery at the authors' institution between 2010 and 2019 were retrospectively included. Tumor volume on pre- and postoperative MRI scans was determined. Clinical and routine neuropathological data were gained from patients' charts. If IDH1, ATRX and EGFR were not routinely assessed, they were re-determined.

RESULTS

Out of 161 patients included, 23 (14%) were diagnosed as incidental findings. Main reasons for obtaining MRI were: headache(n = 12), trauma(n = 2), MRI indicated by other departments(n = 7), staging examination for cancer(n = 1), volunteering for MRI sequence testing(n = 1). The asymptomatic patients were significantly younger with a median age of 38 years (IqR28-48) vs. 50 years (IqR38-61), p = 0.011. Incidental LGG showed significantly lower preoperative tumor volumes in T1 CE (p = 0.008), FLAIR (p = 0.038) and DWI (p = 0.028). Incidental LGG demonstrated significantly lower incidence of anaplasia (p = 0.004) and lower expression of MIB-1 (p = 0.008) compared to sLGG. IDH1-mutation was significantly more common in iLGG (p = 0.024). Incidental LGG showed a significantly longer OS (mean 212 vs. 70 months, p = 0.005) and PFS (mean 201 vs. 61 months, p = 0.001) compared to sLGG.

CONCLUSION

Our study is the first to depict a significant difference in molecular characteristics between iLGG and sLGG. The findings of this study confirmed and extended the results of previous studies showing a better outcome and more favorable radiological, volumetric and neuropathological features of iLGG.

Peritumoral ADC Values Correlate with the MGMT Methylation Status in Patients with Glioblastoma

Different results have been reported concerning the relationship of the apparent diffusion coefficient (ADC) values and the status of methylation as the promoter gene for the enzyme methylguanine-DNA methyltransferase (MGMT) in patients with glioblastomas (GBs). The aim of this study was to investigate if there were correlations between the ADC values of the enhancing tumor and peritumoral areas of GBs and the MGMT methylation status. In this retrospective study, we included 42 patients with newly diagnosed unilocular GB with one MRI study prior to any treatment and histopathological data. After co-registration of ADC maps with T1-weighted sequences after contrast administration and dynamic susceptibility contrast (DSC) perfusion, we manually selected one region-of-interest (ROI) in the enhancing and perfused tumor and one ROI in the peritumoral white matter. Both ROIs were mirrored in the healthy hemisphere for normalization. In the peritumoral white matter, absolute and normalized ADC values were significantly higher in patients with MGMT-unmethylated tumors, as compared to patients with MGMT-methylated tumors (absolute values p = 0.002, normalized p = 0.0007). There were no significant differences in the enhancing tumor parts. The ADC values in the peritumoral region correlated with MGMT methylation status, confirmed by normalized ADC values. In contrast to other studies, we could not find a correlation between the ADC values or the normalized ADC values and the MGMT methylation status in the enhancing tumor parts.

Impact of GAP-43, Cx43 and actin expression on the outcome and overall survival in diffuse and anaplastic gliomas

Distant intercellular communication in gliomas is based on the expansion of tumor microtubuli, where actin forms cytoskeleton and GAP-43 mediates the axonal conus growth. We aimed to investigate the impact of GAP-43 and actin expression on overall survival (OS) as well as crucial prognostic factors. FFPE tissue of adult patients with diffuse and anaplastic gliomas, who underwent first surgery in our center between 2010 and 2019, were selected. GAP-43, Cx43 and actin expression was analyzed using immunohistochemistry and semi-quantitatively ranked. 118 patients with a median age of 46 years (IqR: 35-57) were evaluated. 48 (41%) presented with a diffuse glioma and 70 (59%) revealed anaplasia. Tumors with higher expression of GAP-43 (p = 0.024, HR = 1.71/rank) and actin (p < 0.001, HR = 2.28/rank) showed significantly reduced OS. IDH1 wildtype glioma demonstrated significantly more expression of all proteins: GAP-43 (p = 0.009), Cx43 (p = 0.003) and actin (p < 0.001). The same was confirmed for anaplasia (GAP-43 p = 0.028, actin p = 0.029), higher proliferation rate (GAP-43 p = 0.016, actin p = 0.038), contrast-enhancement in MRI (GAP-43 p = 0.023, actin p = 0.037) and age (GAP-43 p = 0.004, actin p < 0.001; Cx43 n.s. in all groups). The intercellular distant communication network in diffuse and anaplastic gliomas formed by actin and GAP-43 is associated with a negative impact on overall survival and with unfavorable prognostic features. Cx43 did not show relevant impact on OS.

The relationship between connexin-43 expression and Ki67 in non-glial central nervous system tumors

BACKGROUND

Advanced intercellular communication is a known oncogenic factor. In the central nervous system, Connexin-43 (Cx43) forms this junctional networking. Moreover, it correlates with the proliferation rate, and thus behavior, of gliomas. We assessed the expression of Cx43 and its relationship to Ki67 in other common central nervous system tumors.

METHODS

The expression of Cx43 and Ki67 were assessed in formalin-fixed paraffin embedded samples of human brain metastases, meningiomas, and neurinomas using immunohistochemistry. Neurinomas and meningiomas were jointly evaluated due to similar non-malignant behavior.

RESULTS

A total of 14 metastases of different extracerebral carcinomas, 6 meningiomas, and 10 neurinomas were evaluated. Five (36%) metastases and 5 (31%) meningiomas/neurinomas showed minor expression, whereas 6 (43%) metastases and 2 (13%) meningiomas/neurinomas showed no Cx43 expression at all. In 3 (21%) metastases and 9 (56%) meningiomas/neurinomas, moderate or strong expression of Cx43 was identified. The higher expression of Cx43 in meningiomas and neurinomas directly correlated with Ki67, r = 0.53 (P = 0.034). For metastases no significant correlation was found. Mitotic index in meningiomas/neurinomas correlated with Ki67 expression, r = 0.74 (P < 0.001), but did not show statistically significant correlation with Cx43 expression in these tumors.

CONCLUSIONS

The expression of Cx43 as a marker of cell-to-cell networking exposed a significant correlation with the Ki67-defined proliferation index in case of primary central nervous system neuroectodermal neoplasms. However, it does not seem to play a comparable role in metastases with extracerebral origin.

Mind the gap-the use of sodium fluoresceine for resection of brain metastases to improve the resection rate

INTRODUCTION AND PURPOSE

Brain metastases appear to be well resectable due to dissectable tumor margins, but postoperative MRI quite often depicts residual tumor with potential influence on tumor control and overall survival. Therefore, we introduced sodium fluoresceine into the routine workflow for brain metastasis resection. The aim of this study was to evaluate whether the use of fluorescence-guided surgery has an impact on postoperative tumor volume and local recurrence.

MATERIAL AND METHODS

We retrospectively included patients who underwent surgical resection for intracranial metastases of systemic cancer between 11/2017 and 05/2021 at our institution. Tumor volumes were assessed pre- and postoperatively on T1-CE MRI. Clinical and epidemiological data as well as follow-up were gathered from our prospective database.

RESULTS

Seventy-nine patients (33 male, 46 female) were included in this study. Median preoperative tumor volume amounted to 11.7cm3 and fluoresceine was used in 53 patients (67%). Surgeons reported an estimated gross total resection (GTR) in 95% of the cases, while early postoperative MRI could confirm GTR in 72%. Patients resected using fluoresceine demonstrated significantly lower postoperative residual tumor volumes with a difference of 0.7cm3 (p = 0.044) and lower risk of local tumor recurrence (p = 0.033). The use of fluorescence did not influence the overall survival (OS). Postoperative radiotherapy resulted in a significantly longer OS (p = 0.001).

DISCUSSION

While GTR rates may be overrated, the use of intraoperative fluorescence may help neurosurgeons to achieve a more radical resection. Fluoresceine seems to facilitate surgical resection and increase the extent of resection thus reducing the risk for local recurrence.

PATH-03. IMPACT OF GAP-43 AND ACTIN EXPRESSION ON THE OUTCOME AND OVERALL SURVIVAL IN DIFFUSE AND ANAPLASTIC GLIOMAS

Background. Distant intercellular communication in gliomas is based on the expansion of tumor microtubuli (TMs), where actin forms cytoskeleton and GAP-43 mediates the axonal conus growth. We aimed to investigate the impact of GAP-43 and actin expression on overall survival (OS) as well as crucial epidemiologic, radiological and neuropathological prognostic factors. Methods. FFPE tissue of adult patients with diffuse and anaplastic gliomas, who underwent first surgery in our center between 2010 and 2019, were selected. GAP-43 and actin expression was analyzed using immunohistochemistry and semi-quantitatively ranked. Clinical, neuropathological as well as follow-up-data were gained from the institutional neuro-oncological database. Results. 118 patients with a median age of 46 years (IqR: 35 – 57) were evaluated. 48 (41%) presented with a diffuse glioma and 70 (59%) revealed anaplasia. 96 (82%) cases presented with intermediate or strong GAP-43 expression and 78 (67%) with no or light actin expression. Tumors with higher expression of GAP-43 (p=0.024, HR=1.71/rank) and actin (p&lt; 0.001, HR=2.28/rank) showed significantly reduced OS. IDH1 wildtype glioma demonstrated significantly more expression of both proteins: GAP-43 (p=0.009) and actin (p&lt; 0.001). The same was confirmed for anaplasia (GAP-43 p=0.028, actin p=0.029), higher proliferation rate (GAP-43 p=0.016, actin p=0.038), contrast-enhancement in MRI (GAP-43 p=0.023, actin p=0.037) and age (GAP-43 p=0.004, actin p&lt;0.001). Conclusions. The intercellular distant communication network in diffuse and anaplastic gliomas formed by actin and GAP-43 is associated with a negative impact on overall survival and with oncologically unfavorable prognostic features.

RADT-29. THE IMPACT OF TUMOR LOCATION AT THE SKULL BASE ON RADIATION NECROSIS IN PATIENTS UNDERGOING STEREOTACTIC RADIOSURGERY: AN ANALYSIS OF 205 PATIENTS

Background

Skull base (SB) surgery and radiosurgery (SRS) are an interdisciplinary concept and represent an individualized treatment option for various skull base tumors. Radiation necrosis (RN) is a possible sequela of SRS, but despite few accepted risk factors, there is very limited data on the influence of tumor location. The aim of this study was to assess tumor location in correlation to the development of radiation necrosis for skull-base tumors.

METHODS

All patients treated with radiosurgery for meningioma, vestibular schwannoma and other benign neoplasms between January 2004 and November 2020 were retrospectively evaluated. The clinical, imaging and medication data were gained from the patients’ charts. The diagnosis of RN was established retrospectively using imaging parameters. Patients with tumors located at the skull base were compared to patients with tumors of other location.

RESULTS

A total of 205 patients could be included in this study. 157 neoplasms (76.6%) were localized at the SB, while the remaining 48 (23.4%) were non-SB. 32 (15.6%) of all patients developed RN after median 10 (IqR 5-12) months during a median follow-up of 24 (IqR 6-62) months. SB-tumors showed a significantly lower risk of radiation necrosis with a Hazard Ratio (HR) of 0.252, p &lt; 0.001, independently of the applied radiation dose. Furthermore, higher radiation doses had a significant impact on the occurrence of RN (HR 1.372, p = 0.002). No significant difference could be shown for age, previous resection or previous radiosurgery. Administered dose of dexamethasone did not correlate with the risk of radiation necrosis.

CONCLUSION

The risk for development of RN for SB-tumors appears to be low. No difference between recurrent and newly diagnosed tumors was found, which may underpin the value of radiosurgical treatment for patients with recurrent SB-tumors. For extensive tumors of the SB, combinations of surgery and radiosurgery represents a valuable approach.

QOL-13. THE ROLE OF EPILEPSY IN ELDERLY PATIENTS WITH GLIOBLASTOMA: AN AUSTRIAN MULTICENTER ANALYSIS

BACKGROUND

With an aging population, acquisition of a better understanding of prognostic factors in elderly patients with Glioblastoma multiforme (GBM) is of utmost importance. Epileptic seizures have been found to correlate with improved overall survival (OS) in low-grade gliomas; however, the impact of epilepsy in GBM patients on outcome parameters is poorly defined. This study aims at specifically evaluating the impact of epilepsy in elderly GBM patients. Material &

METHODS

Two Austrian academic neurosurgical centers retrospectively analyzed all elderly (≥ 65 years) GBM patients with de-novo tumors, who underwent surgery between 09/2006 and 07/2021. Epidemiological, histopathological and survival data were gained from patients’ electronic charts and screened for presence of epilepsy preoperatively or during follow-up. Tumor volume was assessed using standardized software.

RESULTS

391 patients (55% males, 45% females) with a median age at surgery of 73 years (IqR 68.5-77.5) were analyzed. The mean predicted OS was 12.4 months (CI95% 10.9-14.0). Mean follow-up was 10.4 months (CI95% 9.1-11.6) in our cohort. Median tumor volume amounted to 26.47 cm3 (IqR 12.65-43.49). 95 patients (24%) suffered from preoperative epilepsy. 17 (18%) patients showed epilepsy after tumor resection. Four patients (1.0%) showed a worsening of already preoperatively diagnosed seizures. Patients with lower tumor volumes experienced significantly more often seizures compared to patients with larger tumors, p&lt; 0.001. Survival did not correlate with preoperative epilepsy (p &gt; 0.05). However, Cox-regression revealed that multifocal tumor location (HR=1.777, p=0.025) and thalamic involvement (HR=11.121, p=0.030) influenced OS. Surgery-associated complications shortened OS significantly (HR=1.945 [CI95% 1,296-2,916], p=0.025).

CONCLUSION

Even though epilepsy was not found to directly impact survival in elderly GBM patients, we found that surgery led to epilepsy freedom in a significant proportion of our patient cohort, thereby potentially leading to improved QoL. Greatest focus should be set on avoiding any surgery-associated deficits, since these severely influence the OS.

P08.04.B The Clinical Frailty Scale is superior to the Karnofsky Performance Status as predictor of overall survival in patients with surgical treatment of brain metastases

Background

The Clinical Frailty Scale (CFS) evaluates patients’ level of frailty on a scale from 1 (very fit) to 9 (terminally ill) and is commonly used in geriatric medicine, intensive care and orthopaedics but not in patients harboring neuro-oncological diseases. Our study was conducted to reveal if the usage of CFS generates more reliable prediction of overall survival in patients after brain metastases resection rather than Karnofsky Performance Status (KPS).

Material and Methods

All patients which were operated for brain metastatic disease at our department from 2005-2019 were included. CFS and KPS were retrospectively assessed for the timepoints pre- and postoperatively as well during follow-up 3-6 months after resection.

Results

205 patients with mean follow-up of 22.8 months (CI95% 18.4-27.1) were evaluated. Mean estimated OS was 32.1 months (CI95% 25.0-39.1). CFS showed a median of 3 points (IqR 2-4) at all 3 assessment-points which means patients were “managing well”. Median KPS was 80 preoperative (IqR 80-90) and 90 (IqR 80-100) postoperative as well as on follow-up after 3-6 months. CFS strongly correlated with KPS: preoperatively (r=-0.92; p&lt; 0.001), postoperatively (r=-0.85; p&lt;0.001) and at follow-up (r=-0.93; p&lt;0.001). In the same time, CFS pre- and postoperatively showed only weak correlation with CFS at follow-up after 3-6 months (r=0.30, p&lt;0.001; and r=0.37, p&lt;0.001, correspondingly). In multivariate integrated Cox regression model, the CFS predicted the expected reduction of OS superior to KPS at all 3 assessment-points. One point increase of preoperative CFS represented 30% additional hazard to decease (HR=1.30, CI95% 1.15-1.46; p&lt;0.001), correspondingly postoperative CFS provides 39% (HR=1.39, CI95% 1.25-1.54; p&lt;0.001) and at follow-up 42% of hazard (HR= 1.42, CI95% 1.27-1.59; p&lt;0.001). In case of KPS, decrease of 10 points resulted in additional hazards to decease of 26% (HR=0.974/point, CI95% 0.962-0.987; p&lt;0.001) postoperatively 14% (HR=0.986/point, CI95% 0.978-0.993; p&lt;0.001) and 31% (HR=0.969/point, CI95% 0.959-0.978; p&lt;0.001) at follow-up.

Conclusion

CFS is a feasible and reliable performance scoring in patients undergoing brain metastasis resection, that provides better OS prediction as compared to KPS. Whereas, CFS at follow-up after 3-6 months specifies the expected OS most accurately. Due to weak correlation between CFS preoperatively vs. postoperatively and in 3-6 months, initial frailty does not predict the patients’ postoperative frailty score.

P12.05.B Impact of GAP-43 and actin expression on the outcome and overall survival in diffuse and anaplastic gliomas

Background

Distant intercellular communication in gliomas is based on the expansion of tumor microtubuli (TMs), where actin forms cytoskeleton and GAP-43 mediates the axonal conus growth. We aimed to investigate the impact of GAP-43 and actin expression on overall survival (OS) as well as crucial epidemiologic, radiological and neuropathological prognostic factors.

Material and Methods

FFPE tissue of adult patients with diffuse and anaplastic gliomas, who underwent first surgery in our center between 2010 and 2019, were selected. GAP-43 and actin expression was analyzed using immunohistochemistry and semi-quantitatively ranked. Clinical, neuropathological as well as follow-up-data were gained from the institutional neuro-oncological database.

Results

118 patients with a median age of 46 years (IqR: 35 - 57) were evaluated. 48 (41%) presented with a diffuse glioma and 70 (59%) revealed anaplasia. 96 (82%) cases presented with intermediate or strong GAP-43 expression and 78 (67%) with no or light actin expression. Tumors with higher expression of GAP-43 (p=0.024, HR=1.71/rank) and actin (p&lt;0.001, HR=2.28/rank) showed significantly reduced OS. IDH wildtype glioma demonstrated significantly more expression of both proteins: GAP-43 (p=0.009) and actin (p&lt;0.001). The same was confirmed for anaplasia (GAP-43 p=0.028, actin p=0.029), higher proliferation rate (GAP-43 p=0.016, actin p=0.038), contrast-enhancement in MRI (GAP-43 p=0.023, actin p=0.037) and age (GAP-43 p=0.004, actin p&lt;0.001).

Conclusion

The intercellular distant communication network in diffuse and anaplastic gliomas formed by actin and GAP-43 is associated with a negative impact on overall survival and unfavorable prognostic features.

P11.55.B Postoperative MRI is able to detect an unexpected residual tumor after surgery of brain metastases: experience from 5 specialized centers

Background

Brain metastases (BM) constitute the most common central nervous system tumors. The treatment options of BM consist of surgery, radiotherapy, radiosurgery, chemotherapy, and immunotherapy. Regarding surgery in BM, the extent of resection (EOR) represents a crucial factor for patient prognosis. However, first studies using postoperative MRI demonstrated that an unexpected residual tumor after surgery of BM is not uncommon despite these tumors were considered to be well-demarcated. The aim of this study was thus to investigate in a large cohort including multiple neurosurgical centers the EOR following BM resection, potential risk factors for incomplete resection and postsurgical follow-up data.

Material and Methods

In the current retrospective study conducted at 5 specialized neurosurgical centers in Austria, we included patients with BM resection and available postoperative MRI. The EOR following BM resection was determined by postoperative MRI (complete vs incomplete resection). Additionally, the data on the intraoperative judgement of the EOR of the performing neurosurgeon were collected. Moreover, potential factors for incomplete resection including tumor localization, tumor volume, primary tumor, pattern of contrast media enhancement on imaging and tumor eloquence were investigated. Finally, the rate of local progression of BM after initial surgery was analyzed in the follow-up period and overall survival data were collected.

Results

Altogether, 548 patients with 649 surgically treated BM were included. According to postoperative MRI, complete resection was achieved in 407 (66%) of 649 BM and incomplete resection in 176 (29%) of 649 BM. Misjudgment of the EOR by the neurosurgeon was found in 25% of cases and resulted in an unexpected residual tumor which was evident on postoperative MRI in 122 (22%) BM. Preoperative tumor volume was significantly larger in incompletely resected BM. Moreover, local progression was significantly more common in cases with incompletely resected BM and was also associated with shorter overall survival.

Conclusion

Our data of this study including multiple centers indicate that postoperative MRI is capable to detect a relatively high rate of unexpected residual tumors following resection of BM. Since local progression was more common in BM with residual tumors and this was associated with shorter survival, special attention should be paid to achieve a complete tumor resection.

OS02.7.A The role of epilepsy in elderly patients with Glioblastoma: An Austrian multicenter analysis

Background

Higher age is a significant predictor of poor outcome in glioblastoma multiforme (GBM) patients. Thus, acquisition of a better understanding of additional prognostic factors in these often-frail patients is of utmost importance. Epileptic seizures correlate with improved overall survival (OS) in low-grade gliomas; however, the impact of epilepsy in GBM patients on outcome parameters is poorly defined. Furthermore, persisting epilepsy significantly influences the patients’ quality of life (QoL). This study aims at specifically evaluating the impact of epilepsy in elderly GBM patients.

Material and Methods

Two Austrian academic neurosurgical centers retrospectively analyzed all elderly (≥65 years) GBM patients with de-novo tumors, who underwent tumor resections between 09/2006 and 07/2021. Epidemiological, histopathological and survival data were gained from patients’ electronic charts and screened for presence of epilepsy preoperatively or during follow-up.

Results

391 patients (55% males, 45% females) with a median age at surgery of 73 years (Interquartile Range (IqR) 68.5-77.5) were analyzed. The mean predicted OS was recorded to be 12.4 months (CI95% 10.9-14.0). Median preoperative Modified Rankin Scale (mRS) was 2 (IqR 1-3), and median preoperative Karnofsky performance score was 80 (IqR 60-90). Mean follow-up was 10.4 months (CI95% 9.1-11.6) in our cohort. 95/391 patients (24%) suffered from preoperative epilepsy. 17 (18%) patients still suffered from epilepsy after tumor resection with eight patients who developed new postoperative seizures, and four patients (1.0%) showed a worsening of already preoperatively diagnosed seizures. Major surgery-associated neurological complications included new motor deficits in 29 (7%) and new aphasia in 16 (4%) patients. Logistic regression showed, patients with seizures had significantly lower mRS (OR=0.735 [CI95% 0.563 0.961], p=0.032) and less frequently occipital tumor location (OR=0.347 [CI95% 0.152-0.791], p=0.018). Postoperative epilepsy resulted in significantly prolonged hospitalization after the surgery (OR=2.622[CI95% 1.496-3.979], p=0.009). Survival did not correlate with preoperative epilepsy (p&gt;0.05). However, Cox regression revealed that multifocal tumor location (HR=1.777 [CI95% 1.197-2.639], p=0.025) as well as thalamic involvement (HR=11.121 [CI95% 3.431-36,046], p=0.030) negatively influenced OS. Furthermore, surgery-associated complications shortened OS significantly (HR=1.945 [CI95% 1,296-2,916], p=0.025).

Conclusion

Even though epilepsy was not found to directly impact survival in elderly GBM patients, we found that surgery led to epilepsy freedom in a significant proportion of our patient cohort, thereby potentially leading to improved QoL. Greatest focus should be set on avoiding any surgery-associated deficits, since these severely influence the OS.

P11.10.A An assessment of predictive factors for overall survival in glioblastoma - MGMT methylation is solely important for younger patients

Background

Diverse groups of factors - neuropathological characters, tumor position and epidemiological data - have been proposed for outcome evaluation of glioblastoma (GBM). We compared clinical signs, neuropathological features and the locus of the tumor with the follow-up data.

Material and Methods

All adult patients with firstly diagnosed and histologically proven GBM (according to WHO 2016), which were operated in our center between January 2010 and June 2021 were retrospectively assessed. Epidemiological, clinical and neuro-pathological characteristics were acquired from our institutional neuro-oncological database.

Results

A total of 399 patients could be evaluated. The mean follow-up was 13.9 months (CI95 12.2-15.6), within 266 (67%) patients were deceased. Estimated mean OS for entire cohort was 24.2 months (CI95 19.8-28.7). Age, MGMT promoter methylation, brainstem localization or if a patient received biopsy only showed significant impact on OS. Each year of life accounted for 3.4% additional hazard to decease (HR=1.034, CI95 1.020-1.048, p&lt;0.001). If patients were younger than 65 years, mean OS was 34 months (CI95 26.5-41.8) compared to older than 65 years patients with a mean OS of 14.3 months (CI95 10.5-18.1, p&lt;0.001). Generally, an unmethylated MGMT promoter status was linked to 75% higher hazards to decease (HR 1.75, CI95 1.27-2.40, p=0.027). If MGMT promoter status was methylated, mean OS was 25.7 months (CI95 19.9-31.5) or more compared to unmethylated with 14.5 months (CI95 12.0-16.9, p=0.01). Presence of MGMT promoter methylation showed influence on OS only in the younger cohort (&lt;65y, mean OS 38.7 months [CI95 28.9-48.6]; HR 2.60 [CI95 1.55-4.37], p&lt;0.001) as opposed to unmethylated MGMT (mean OS 17.7 months [CI95 14.1-21.2], p&lt;0.001). In the older cohort (&gt;65y) presence of methylated MGMT promoter showed no significant difference (p=0.364). For patients who received only biopsy, 2.4 times more hazards for worse OS were revealed (HR 3.36, CI95% 2.30-4.90, p&lt;0.001). In these cases, mean OS was 7.1 months (CI95 5.3-8.8). Other factors, including gender or preoperative seizures, as well as EGFR, p53, IDH1, ATRX and TERT status did not show impact on OS in our series.

Conclusion

In our cohort, MGMT promoter methylation showed an impact on OS only in younger patients &lt;65 years of age. Biopsy of GBM should only be considered very selected patients when resection is not possible.

P08.02.B The Clinical Frailty Scale as predictor of overall survival after resection of high-grade glioma

Background

The Clinical Frailty Scale (CFS) describes the general level of fitness or frailty and is widely used in geriatric medicine, intensive care and orthopaedic surgery. This study was conducted to analyze, whether CFS could be used for patients with high-grade glioma.

Material and Methods

Patients harboring high-grade gliomas, undergoing first resection at our center between 2015 and 2020 were retrospectively evaluated. Patients’ performance was assessed using the Rockwood Clinical Frailty Scale and the Karnofsky Performance Scale (KPS) preoperatively and 3-6 months postoperatively.

Results

289 patients were included. Pre- as well as postoperative median frailty was 3 CFS points (IqR 2-4) corresponding to “managing well”. CFS strongly correlated with KPS preoperatively (r = -0.85; p &lt; 0.001) and at the 3-6 months follow-up (r = -0.90; p &lt; 0.001). The reduction of overall survival (OS) was 54% per point of CFS preoperatively (HR 1.54, CI95% 1.38-1.70; p &lt; 0.001) and 58% at the follow-up (HR 1.58, CI95% 1.41-1.78; p &lt; 0.001), comparable to KPS. Patients with IDH mutation showed significantly better preoperative and follow-up CFS and KPS (p &lt; 0.05). Age and performance scores correlated only mildly with each other (r = 0.21⋯0.35; p &lt; 0.01), but independently predicted OS (p &lt; 0.001 each).

Conclusion

CFS seems to be a reliable tool for functional assessment of patients suffering from high-grade glioma. CFS includes non-cancer related aspects and therefore is a contemporary approach for patient evaluation. Its projection of survival can be equally estimated before and after surgery. IDH-mutation caused longer survival and higher functionality.

The Routine Application of Tumor-Treating Fields in the Treatment of Glioblastoma WHO° IV

Introduction:

Tumor-treating fields (TTFs) are a specific local oncological treatment modality in glioblastoma multiforme WHO° IV (GBM). Their mechanism of action is based on the effect of electrical fields interfering with the mitotic activity of malignant cells. Prospective studies have demonstrated efficacy, but TTF benefits are still controversially discussed. This treatment was implemented in our center as the standard of care in January 2016. We thus discuss the current state of the art and our long-term experience in the routine application of TTF.

Methods

The data of 48 patients suffering from GBM and treated with TTF were assessed and compared with previously published studies. Up-to-date information from open sources was evaluated.

Results

A total of 31 males and 17 females harboring a GBM were treated with TTF, between January 2016 and August 2021, in our center. In 98% of cases, TTFs were started within 6 weeks after concomitant radiochemotherapy (Stupp protocol). Mean overall survival was 22.6 months (95% CI: 17.3–27.9). Current indications, benefits, and restrictions were evaluated. Future TTF opportunities and ongoing studies were reviewed.

Conclusion

TTFs are a feasible and routinely applicable specific oncological treatment option for glioblastoma multiforme WHO° IV. Further research is ongoing to extend the indications and the efficacy of TTF.

Surgical Management of Malignant Glioma in the Elderly

Background

The median age for diagnosis of glioblastoma is 64 years and the incidence rises with increasing age to a peak at 75-84 years. As the total number of high-grade glioma patients is expected to increase with an aging population, neuro-oncological surgery faces new treatment challenges, especially regarding aggressiveness of the surgical approach and extent of resection. In the elderly, aspects like frailty and functional recovery time have to be taken into account before performing surgery.

Material & Methods

Patients undergoing surgery for malignant glioma (WHO grade III and IV) at our institution between 2015 and 2020 were compiled in a centralized tumor database and analyzed retrospectively. Karnofsky Performance Scale (KPS) and Clinical Frailty Scale (CFS) were used to determine functional performance pre- and postoperatively. Overall survival (OS) was compared between age groups of 65-69 years, 70-74 years, 75-79 years, 80-84 years and >85 years in view of extent of resection (EOR). Furthermore, we performed a literature evaluation focusing on surgical treatment of newly diagnosed malignant glioma in the elderly.

Results

We analyzed 121 patients aged 65 years and above (range 65 to 88, mean 74 years). Mean overall survival (OS) was 10.35 months (SD = 11.38). Of all patients, only a minority (22.3%) received tumor biopsy instead of gross total resection (GTR, 61.2%) or subtotal resection (STR, 16.5%). Postoperatively, 52.9% of patients were treated according to the Stupp protocol. OS differed significantly between extent of resection (EOR) groups (4.0 months after biopsy vs. 8.3 after STR vs. 13.8 after GTR, p < 0.05 and p < 0.001 correspondingly). No significant difference was observed regarding EOR across different age groups.

Conclusion

GTR should be the treatment of choice also in elderly patients with malignant glioma as functional outcome and survival after surgery are remarkably better compared to less aggressive treatment. Elderly patients who received GTR of high-grade gliomas survived significantly longer compared to patients who underwent biopsy and STR. Age seems to have little influence on overall survival in selected surgically extensive treated patients, but high preoperative functional performance is mandatory.

Correction of temporal hollowing after pterional craniotomy by autologous fat grafting. A single-center experience

OBJECTIVE

Aesthetic complications following neurosurgical procedures impact patient quality of life and self-perception. Postoperative temporal hollowing is frequently seen after temporal craniotomy, resulting mainly from atrophy of the temporal muscle. Autologous fat grafting is a tailorable method to correct such approach-related sequelae. We herein present our clinical patient series and discuss pearls and pitfalls of this method.

METHODS

In this retrospective single-center study, correction of postoperative temporal hollowing using autologous fat grafting was performed in 16 patients. Temporal tissue thickness ratio was measured using magnetic resonance tomography images to visualize the graft. Patients, plastic surgeons and neurosurgeons evaluated the results independently using the herein presented scale.

RESULTS

The mean interval between the neurosurgical procedure and fat grafting was 62 months. A mean volume of 11.5 ml autologous fat was injected in an average of 2.5 sessions after initial rigotomy. Temporal tissue thickness was significantly augmented at a mean of 2.2 years after the operation (mean 0.71 ± 0.25, range 0.43-1.1; p=0.0214) as compared to the preoperative finding (mean 0.48 ± 0.1, range 0.32-0.6). Patients were more satisfied with the results than were surgeons, reflecting the significant impact of the deformity on patient self-esteem.

CONCLUSIONS

Autologous fat grafting is a valuable method for correcting postoperative temporal hollowing that provides stable results, high patient and surgeon satisfaction and can be tailored to the patient's individual needs. It should not be considered a merely aesthetic operation, but an important rehabilitation step towards restoring the patient's quality of life.

The Clinical Frailty Scale as predictor of overall survival after resection of high-grade glioma

BACKGROUND

The Clinical Frailty Scale (CFS) describes the general level of fitness or frailty and is widely used in geriatric medicine, intensive care and orthopaedic surgery. This study was conducted to analyze, whether CFS could be used for patients with high-grade glioma.

METHODS

Patients harboring high-grade gliomas, undergoing first resection at our center between 2015 and 2020 were retrospectively evaluated. Patients' performance was assessed using the Rockwood Clinical Frailty Scale and the Karnofsky Performance Scale (KPS) preoperatively and 3-6 months postoperatively.

RESULTS

289 patients were included. Pre- as well as postoperative median frailty was 3 CFS points (IqR 2-4) corresponding to "managing well". CFS strongly correlated with KPS preoperatively (r = - 0.85; p < 0.001) and at the 3-6 months follow-up (r = - 0.90; p < 0.001). The reduction of overall survival (OS) was 54% per point of CFS preoperatively (HR 1.54, CI 95% 1.38-1.70; p < 0.001) and 58% at the follow-up (HR 1.58, CI 95% 1.41-1.78; p < 0.001), comparable to KPS. Patients with IDH mutation showed significantly better preoperative and follow-up CFS and KPS (p < 0.05). Age and performance scores correlated only mildly with each other (r = 0.21…0.35; p < 0.01), but independently predicted OS (p < 0.001 each).

CONCLUSION

CFS seems to be a reliable tool for functional assessment of patients suffering from high-grade glioma. CFS includes non-cancer related aspects and therefore is a contemporary approach for patient evaluation. Its projection of survival can be equally estimated before and after surgery. IDH-mutation caused longer survival and higher functionality.

Surgeon's comfort: The ergonomics of a robotic exoscope using a head-mounted display

Introduction

Conventional microscopes have certain limitations in terms of posture and ergonomics. Monitor-based exoscopes could solve this problem and thereby lead to less work-related sick leave for surgeons.

Research question

The aim of this study was to assess the ergonomics, usability, and neurosurgeon's comfort of a novel three-dimensional head-mounted display-based exoscope in a standardized setting.

Material & Methods

34 neurosurgeons participated in a workshop on the exoscope, which features a head-mounted display and a head gesture-triggered control panel. After completion of a custom-made 10-step microsurgical exercise, image quality and comfort were assessed using a questionnaire. The participants' posture during the exercise was analyzed using a video motion analysis software.

Results

34 participants (median neurosurgical experience: 6 years) were included. The median time to complete the exercise was 12 ​min [IqR 9.4, 15.0]. Younger participants (p ​= ​0.005) and those with video game experience (p ​= ​0.03) had a significantly steeper learning curve. The median overall satisfaction was at 80% in general and 82% for image quality. The median upper body as well as the median head coronal displacement from the neutral axis were 0°. Participants with less microsurgical experience showed less head/body displacement during the exercise (p ​= ​0.01).

Discussion and conclusion

Using the microsurgical training tool, we were able to depict a steep learning curve with a sufficient learnability of the most relevant commands. The exoscope excelled in usability, image quality as well as in ergonomic and favorable posture and could thus become an alternative to conventional microscopes due to the potentially elevated surgeons' comfort.

•

Overall, the participants were satisfied with the exoscope usability (80%) and image quality (82%).

•

The custom-made microsurgical exercise tool is an efficient tool for assessment of the participant's performance with the head-mounted display-based exoscope.

•

Younger participants with video games experience showed a steeper learning curve for the performance of the microsurgical training tool.

•

After performing theexercise, 88% of the participants felt safe to use the HMD-based exoscope in the OR.

Novel microscope-based visual display and nasopharyngeal registration for auditory brainstem implantation: a feasibility study in an ex vivo model

Purpose

An auditory brainstem implant (ABI) represents an alternative for patients with profound hearing loss who are constrained from receiving a cochlear implant. The positioning of the ABI electrode influences the patient’s auditory capacity and, therefore, quality of life and is challenging even with available intraoperative electrophysiological monitoring. This work aims to provide and assess the feasibility of visual-spatial assistance for ABI positioning.

Methods

The pose of the forceps instrument that grasps the electrode was electromagnetically navigated and interactively projected in the eyepieces of a surgical microscope with respect to a target point. Intraoperative navigation was established with an experimental technique for automated nasopharyngeal patient registration. Two ABI procedures were completed in a human specimen head.

Results

An intraoperative usability study demonstrated lower localization error when using the proposed visual display versus standard cross-sectional views. The postoperative evaluations of the preclinical study showed that the center of the electrode was misplaced to the planned position by 1.58 mm and 3.16 mm for the left and the right ear procedure, respectively.

Conclusion

The results indicate the potential to enhance intraoperative feedback during ABI positioning with the presented system. Further improvements consider estimating the pose of the electrode itself to allow for better orientation during placement.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11548-021-02514-x.

Phosphorous Magnetic Resonance Spectroscopy and Molecular Markers in IDH1 Wild Type Glioblastoma

Simple Summary

Gliobastoma is one of the deadliest tumors overall, yet the most common malignant brain tumor. The new World Health Organization Classification of Brain Tumors brought changes in how we look at this type of malignancy. Now we know that glioblastoma is rather a spectrum of similar tumors, but with some distinct characteristics that include molecular footprint, response to therapy and with that overall survival, among others. We hypothesised that by employing phosphorous magnetic resonance we will be able to show differences in cellular energy metabolism in these various subtypes of glioblastoma. For example, we found indices of faster cell reproduction and tumor growth in MGMT-methylated and EGFR-amplified tumors. These tumors also could have reduced energetic state or tissue oxygenation due to the increased necrosis. Tumors with EGFR-amplification could have increased apoptotic activity regardless of their MGMT status. Our study indicated various differences in energetic metabolism in tumors with different molecular characteristics, which could potentially be important in future therapeutic strategies.

Abstract

The World Health Organisation’s (WHO) classification of brain tumors requires consideration of both histological appearance and molecular characteristics. Possible differences in brain energy metabolism could be important in designing future therapeutic strategies. Forty-three patients with primary, isocitrate dehydrogenase 1 (IDH1) wild type glioblastomas (GBMs) were included in this study. Pre-operative standard MRI was obtained with additional phosphorous magnetic resonance spectroscopy (31-P-MRS) imaging. Following microsurgical resection of the tumors, biopsy specimens underwent neuropathological diagnostics including standard molecular diagnosis. The spectroscopy results were correlated with epidermal growth factor (EGFR) and O6-Methylguanine-DNA methyltransferase (MGMT) status. EGFR amplified tumors had significantly lower phosphocreatine (PCr) to adenosine triphosphate (ATP)-PCr/ATP and PCr to inorganic phosphate (Pi)-PCr/Pi ratios, and higher Pi/ATP and phosphomonoesters (PME) to phosphodiesters (PDE)-PME/PDE ratio than those without the amplification. Patients with MGMT-methylated tumors had significantly higher cerebral magnesium (Mg) values and PME/PDE ratio, while their PCr/ATP and PCr/Pi ratios were lower than in patients without the methylation. In survival analysis, not-EGFR-amplified, MGMT-methylated GBMs showed the longest survival. This group had lower PCr/Pi ratio when compared to MGMT-methylated, EGFR-amplified group. PCr/Pi ratio was lower also when compared to the MGMT-unmethylated, EGFR not-amplified group, while PCr/ATP ratio was lower than all other examined groups. Differences in energy metabolism in various molecular subtypes of wild-type-GBMs could be important information in future precision medicine approach.

Repeated 31P-MRS in severe traumatic brain injury: Insights into cerebral energy status and altered metabolism

Phosphorous magnetic resonance spectroscopy (31P-MRS) is suited to non-invasively investigate energy metabolism and to detect molecules containing phosphorus in the human brain. The aim of this longitudinal study was to perform 31P-MRS at two different time points (within 72 hours and between day 10-14) after severe traumatic brain injury (sTBI) to reveal alterations in cerebral energy metabolism. Twenty-six ventilated sTBI patients, aged between 20 to 75 years, with a median initial GCS of 5 were prospectively analyzed. 31P-MRS data of the structurally more affected side were compared to data from contralateral normal appearing areas and to data of age- and gender-matched healthy controls. There were no significant intraindividual differences between the lesioned and the less affected side at either of time points. In the acute phase, PCr/ATP and PCr/Pi were significantly elevated whereas PME/PDE and Pi/ATP were significantly decreased in contrast to healthy controls. In the subacute phase these differences gradually dissipated, remaining lower Pi/ATP ratio, and only partly altered levels of PCr/Pi and PME/PDE. Our data affirm that cerebral metabolism is globally altered after sTBI, demonstrating the diffuse impairment of brain bioenergetics at multiple levels, with resultant developments in terms of time.

Hypofractionated and single-fraction radiosurgery for brain metastases with sex as a key predictor of overall survival

Overall survival (OS) of patients with brain metastases treated with hypofractionated (HFSRT) or single-fraction (SRS) radiosurgery depends on several prognostic factors. The aim of this study was to investigate the potential of sex as an independent predictor of OS and evaluate the predictive accuracy of common prognostic scores. Retrospective analysis of 281 consecutive patients receiving radiosurgery of brain metastases was performed. Kaplan-Meier survival curves and Cox proportional hazards models were used to compare OS between SRS and HFSRT and by sex, before and after propensity-score matching (PSM) on key baseline prognostic covariates. Prognostic scores were evaluated using Harrell's concordance index. Median OS was 11 months after both SRS and HFSRT. After PSM, median OS was 12 months after SRS (95% CI: 7.5-16.5) and 9 months after HFSRT (95% CI: 5.0-13.0; p = 0.77). Independent prognostic factors were sex, primary tumor, KPI, and systemic disease status. Median OS was 16 months for women and 7 months for male patients (p < 0.001). After excluding sex specific tumors, PSM revealed a median OS of 16 months for women and 8 months for male patients (p < 0.01). Evaluation of prognostic indices showed BSBM to be the most accurate (Harrell's C = 0.68), followed by SIR (0.61), GPA (0.60), RPA (0.58), and Rades et al. (0.57). OS after HFSRT and SRS did not differ, although PSM revealed a non-significant advantage for SRS. Female sex was found to be a major independent positive prognostic factor for survival, and thus should be considered in the personalized decision-making of brain metastases treatment.

Case report: successful perioperative management of patients with haemophilia A using an extended half-life factor VIII (Efmoroctocog alfa) during neurosurgical procedures

Patients with haemophilia A (HA) undergoing neurosurgical procedures have a high risk of haemorrhage with potential fatal outcome. Here, we present a successful perioperative haemostatic concept applying an extended half-life factor VIII (EHL FVIII), Efmoroctocog alfa, in two patients with HA undergoing neurosurgery for paramedian right-sided disc herniation (case 1) and astrocytoma (case 2). After adequate EHL FVIII treatment the surgical procedures were performed without any bleeding complications despite the high-risk interventions. Laboratory measurements confirmed stable FVIII levels throughout the hospital stay. We suggest close interdisciplinary collaboration between involved clinicians as mandatory prerequisite for an optimized perioperative management in patients with HA. The presented cases indicate, that the increased stability, safety and fewer injections provide a rationale to use EHL FVIII products in HA patients undergoing surgical interventions with a very high bleeding risk.

The association of patient age with postoperative morbidity and mortality following resection of intracranial tumors

Introduction

The postoperative functional status of patients with intracranial tumors is influenced by patient-specific factors, including age.

Research question

This study aimed to elucidate the association between age and postoperative morbidity or mortality following the resection of brain tumors.

Material and methods

A multicenter database was retrospectively reviewed. Functional status was assessed before and 3–6 months after tumor resection by the Karnofsky Performance Scale (KPS). Uni- and multivariable linear regression were used to estimate the association of age with postoperative change in KPS. Logistic regression models for a ≥10-point decline in KPS or mortality were built for patients ≥75 years.

Results

The total sample of 4864 patients had a mean age of 56.4 ​± ​14.4 years. The mean change in pre-to postoperative KPS was −1.43. For each 1-year increase in patient age, the adjusted change in postoperative KPS was −0.11 (95% CI -0.14 - - 0.07). In multivariable analysis, patients ≥75 years had an odds ratio of 1.51 to experience postoperative functional decline (95%CI 1.21–1.88) and an odds ratio of 2.04 to die (95%CI 1.33–3.13), compared to younger patients.

Discussion

Patients with intracranial tumors treated surgically showed a minor decline in their postoperative functional status. Age was associated with this decline in function, but only to a small extent.

Conclusion

Patients ≥75 years were more likely to experience a clinically meaningful decline in function and about two times as likely to die within the first 6 months after surgery, compared to younger patients.

•

A multicenter database of patients with intracranial tumors is analyzed in this study.

•

Age is associated with a minor decline in the postoperative functional status & mortality.

•

Patients ≥75 years are more likely to experience a clinically meaningful decline in function and to die.

Sector Irradiation vs. Whole Brain Irradiation After Resection of Singular Brain Metastasis-A Prospective Randomized Monocentric Trial

To minimize recurrence following resection of a cerebral metastasis, whole-brain irradiation therapy (WBRT) has been established as the adjuvant standard of care. With prolonged overall survival in cancer patients, deleterious effects of WBRT gain relevance. Sector irradiation (SR) aims to spare uninvolved brain tissue by applying the irradiation to the resection cavity and the tumor bed. 40 were randomized to receive either WBRT (n = 18) or SR (n = 22) following resection of a singular brain metastasis. Local tumor control was satisfactory in both groups. Recurrence was observed earlier in the SR (median 3 months, 1–6) than in the WBRT cohort (median 8 months, 7–9) (HR, 0.63; 95% CI, 0.03–10.62). Seventeen patients experienced a distant intracranial recurrence. Most relapses (n = 15) occurred in the SR cohort, whereas only two patients in the WBRT group had new distant tumor manifestation (HR, 6.59; 95% CI, 1.71–11.49; p = 0.002). Median overall survival (OS) was 15.5 months (range: 1–61) with longer OS in the SR group (16 months, 1–61) than in the WBRT group (13 months, 3–52), without statistical significance (HR, 0.55; 95% CI, 0.69–3.64). Concerning neurocognition, patients in the SR group improved in the follow-up assessments, while this was not observed in the WBRT group. There were positive signals in terms of QOL within the SR group, but no significant differences in the global QLQ and QLQ-C30 summary scores were found. Our results indicate comparable efficacy of SR in terms of local control, with better maintenance of neurocognitive function. Unsurprisingly, more distant intracranial relapses occurred.

Clinical Trial Registration:ClinicalTrials.gov, identifier NCT01667640.

Development and external validation of a clinical prediction model for functional impairment after intracranial tumor surgery

OBJECTIVE

Decision-making for intracranial tumor surgery requires balancing the oncological benefit against the risk for resection-related impairment. Risk estimates are commonly based on subjective experience and generalized numbers from the literature, but even experienced surgeons overestimate functional outcome after surgery. Today, there is no reliable and objective way to preoperatively predict an individual patient's risk of experiencing any functional impairment.

METHODS

The authors developed a prediction model for functional impairment at 3 to 6 months after microsurgical resection, defined as a decrease in Karnofsky Performance Status of ≥ 10 points. Two prospective registries in Switzerland and Italy were used for development. External validation was performed in 7 cohorts from Sweden, Norway, Germany, Austria, and the Netherlands. Age, sex, prior surgery, tumor histology and maximum diameter, expected major brain vessel or cranial nerve manipulation, resection in eloquent areas and the posterior fossa, and surgical approach were recorded. Discrimination and calibration metrics were evaluated.

RESULTS

In the development (2437 patients, 48.2% male; mean age ± SD: 55 ± 15 years) and external validation (2427 patients, 42.4% male; mean age ± SD: 58 ± 13 years) cohorts, functional impairment rates were 21.5% and 28.5%, respectively. In the development cohort, area under the curve (AUC) values of 0.72 (95% CI 0.69-0.74) were observed. In the pooled external validation cohort, the AUC was 0.72 (95% CI 0.69-0.74), confirming generalizability. Calibration plots indicated fair calibration in both cohorts. The tool has been incorporated into a web-based application available at https://neurosurgery.shinyapps.io/impairment/.

CONCLUSIONS

Functional impairment after intracranial tumor surgery remains extraordinarily difficult to predict, although machine learning can help quantify risk. This externally validated prediction tool can serve as the basis for case-by-case discussions and risk-to-benefit estimation of surgical treatment in the individual patient.

Perioperative imaging in patients treated with resection of brain metastases: a survey by the European Association of Neuro-Oncology (EANO) Youngsters committee

BACKGROUND

Neurosurgical resection represents an important treatment option in the modern, multimodal therapy approach of brain metastases (BM). Guidelines for perioperative imaging exist for primary brain tumors to guide postsurgical treatment. Optimal perioperative imaging of BM patients is so far a matter of debate as no structured guidelines exist.

METHODS

A comprehensive questionnaire about perioperative imaging was designed by the European Association of Neuro-Oncology (EANO) Youngsters Committee. The survey was distributed to physicians via the EANO network to perform a descriptive overview on the current habits and their variability on perioperative imaging. Chi square test was used for dichotomous variables.

RESULTS

One hundred twenty physicians worldwide responded to the survey. MRI was the preferred preoperative imaging method (93.3%). Overall 106/120 (88.3%) physicians performed postsurgical imaging routinely including MRI alone (62/120 [51.7%]), postoperative CT (29/120 [24.2%]) and MRI + CT (15/120 [12.5%]). No correlation of postsurgical MRI utilization in academic vs. non-academic hospitals (58/89 [65.2%] vs. 19/31 [61.3%], p = 0.698) was found. Early postoperative MRI within ≤72 h after resection is obtained by 60.8% of the participants. The most frequent reason for postsurgical imaging was to evaluate the extent of tumor resection (73/120 [60.8%]). In case of residual tumor, 32/120 (26.7%) participants indicated to adjust radiotherapy, 34/120 (28.3%) to consider re-surgery to achieve complete resection and 8/120 (6.7%) to evaluate both.

CONCLUSIONS

MRI was the preferred imaging method in the preoperative setting. In the postoperative course, imaging modalities and timing showed high variability. International guidelines for perioperative imaging with special focus on postoperative MRI to assess residual tumor are warranted to optimize standardized management and adjuvant treatment decisions for BM patients.

Results of Phosphorus Magnetic Resonance Spectroscopy for Brain Metastases Correlate with Histopathologic Results

BACKGROUND

Brain metastases (BMs) are classically well-circumscribed lesions. Still, the amount of edema in these neoplasms suggests either mechanisms of infiltration or defense. A better understanding of the mechanisms within the edema of BMs seems reasonable to preoperatively identify areas of potential infiltration and resect them. BMs represent tumors with high energy demand and cell turnover; therefore, they qualify for preoperative investigation with phosphorus-31 magnetic resonance spectroscopy (31PMRS), which reveals information about those characteristics.

METHODS

Ten patients with BMs were included in this trial. All underwent preoperative standard magnetic resonance imaging with additional 31PMRS. In all patients, 1 voxel within the contrast-enhancing tumor (CE+), 1 voxel at the border (including CE+ areas and surrounding T2-hyperintensive [T2+] areas), and 1 distant voxel purely including T2+ areas were determined by a neuroradiologist and a neurosurgeon. A frameless stereotactic biopsy was performed after craniotomy. Subsequently, the metabolites of the 31PMRS were analyzed and compared with the histopathologic results.

RESULTS

Ratios, reflecting resynthesis (CE+/border/T2+: 1.109 ± 0.192/1.112 ± 0.158/1.083 ± 0.097), hydrolysis (0.303 ± 0.089/0.360 ± 0.122/0.321 ± 0.089), energy demand (4.227 ± 2.35/3.453 ± 1.284/3.599 ± 0.833), and membrane turnover (1.239 ± 0.2611/3.453 ± 1.284/3.599 ± 0.283) were calculated and compared intraindividually with a voxel from the contralateral side (resynthesis/hydrolysis/energy demand/membrane turnover: 1.063 ± 0.085/0.335 ± 0.073/3.317 ± 0.7573/0.784 ± 0.186), respectively. Resynthesis showed a trend toward higher ratios in CE+ and border biopsies without reaching statistical significances. This trend was also seen concerning energy demand. Membrane turnover was significantly higher in CE+, border zone, and also in the T2+ areas compared with controls (P > 0.001).

CONCLUSIONS

31PMRS in BMs provides information on metabolic changes in tumor and surrounding edema. There is proof of enhanced metabolism in tissue without histologic tumor manifestation.

Imaging practice in low-grade gliomas among European specialized centers and proposal for a minimum core of imaging

OBJECTIVE

Imaging studies in diffuse low-grade gliomas (DLGG) vary across centers. In order to establish a minimal core of imaging necessary for further investigations and clinical trials in the field of DLGG, we aimed to establish the status quo within specialized European centers.

METHODS

An online survey composed of 46 items was sent out to members of the European Low-Grade Glioma Network, the European Association of Neurosurgical Societies, the German Society of Neurosurgery and the Austrian Society of Neurosurgery.

RESULTS

A total of 128 fully completed surveys were received and analyzed. Most centers (n = 96, 75%) were academic and half of the centers (n = 64, 50%) adhered to a dedicated treatment program for DLGG. There were national differences regarding the sequences enclosed in MRI imaging and use of PET, however most included T1 (without and with contrast, 100%), T2 (100%) and TIRM or FLAIR (20, 98%). DWI is performed by 80% of centers and 61% of centers regularly performed PWI.

CONCLUSION

A minimal core of imaging composed of T1 (w/wo contrast), T2, TIRM/FLAIR, PWI and DWI could be identified. All morphologic images should be obtained in a slice thickness of ≤ 3 mm. No common standard could be obtained regarding advanced MRI protocols and PET.

IMPORTANCE OF THE STUDY

We believe that our study makes a significant contribution to the literature because we were able to determine similarities in numerous aspects of LGG imaging. Using the proposed "minimal core of imaging" in clinical routine will facilitate future cooperative studies.

Accuracy Validation of Neuronavigation Comparing Headholder-Based System with Head-Mounted Array-A Cadaveric Study

BACKGROUND

Neuronavigation is widely used for intracranial neurosurgical procedures and is commonly based on the standard reference array being fixed to the headholder. Some cases require the reference array to be attached directly to the head. The aim of this cadaveric study was to compare operational accuracy of a head-mounted reference array with the standard headholder-based system.

METHODS

Navigation accuracy was evaluated with 10 cadaveric specimens. Each specimen was prepared with 8 titanium microscrews that served as reference points on the external skull, and computed tomography was performed. Registration of all specimens was done using surface matching with infrared laser on three-dimensional reconstructed high-resolution computed tomography. In all 10 specimens, the head-mounted reference array and headholder-based system were compared by 10 repetitive measurements. The deviation was evaluated for each screw and compared using nonparametric Mann-Whitney U test between groups and screws. A Bland-Altman plot was generated for comparison.

RESULTS

A total of 1600 measurements were conducted. Mean deviation was 1.97 mm (95% confidence interval, 1.90-2.03 mm) with the head-mounted reference array and 2.10 mm (95% confidence interval, 2.04-2.18 mm) with the headholder based system. There was no significant difference between methods in 9 of 10 specimens. In 1 specimen, the head-mounted array was superior. The deviation in either method showed a significant correlation, indicating high pertinence for registration (P < 0.001).

CONCLUSIONS

Navigation with the head-mounted reference array demonstrated comparable accuracy to the headholder-based system and can be used without reduced accuracy. Careful registration is mandatory.

Spinal ependymoma in adults: a multicenter investigation of surgical outcome and progression-free survival

OBJECTIVE Spinal ependymomas are rare glial neoplasms. Because their incidence is low, only a few larger studies have investigated this condition. There are no clear data concerning prognosis and therapy. The aim of the study was to describe the natural history, perioperative clinical course, and local tumor control of adult patients with spinal ependymomas who were surgically treated under modern treatment standards. METHODS The authors performed a multicenter retrospective study. They identified 158 adult patients with spinal ependymomas who had received surgical treatment between January 2006 and June 2013. The authors analyzed the clinical and histological aspects of these cases to identify the predictive factors for postoperative morbidity, tumor resectability, and recurrence. RESULTS Gross-total resection (GTR) was achieved in 80% of cases. At discharge, 37% of the patients showed a neurological decline. During follow-up the majority recovered, whereas 76% showed at least preoperative status. Permanent functional deterioration remained in 2% of the patients. Transient deficits were more frequent in patients with cervically located ependymomas (p = 0.004) and in older patients (p = 0.002). Permanent deficits were independently predicted only by older age (p = 0.026). Tumor progression was observed in 15 cases. The 5-year progression-free survival (PFS) rate was 80%, and GTR (p = 0.037), WHO grade II (p = 0.009), and low Ki-67 index (p = 0.005) were independent prognostic factors for PFS. Adjuvant radiation therapy was performed in 15 cases. No statistically relevant effects of radiation therapy were observed among patients with incompletely resected ependymomas (p = 0.079). CONCLUSIONS Due to its beneficial value for PFS, GTR is important in the treatment of spinal ependymoma. Gross-total resection is feasible in the majority of cases, with acceptable rates of permanent deficits. Also, Ki-67 appears to be an important prognostic factor and should be included in a grading scheme for spinal ependymomas.

Structured Evaluation of Glioma Patients by an Occupational Therapist-Is Our Clinical Examination Enough?

BACKGROUND

Preservation of neurologic function is mandatory when offering a surgical intervention to patients with low-grade gliomas (LGGs), given that the goal of any treatment is the patient's return to their normal everyday life.

OBJECTIVE

To determine whether a structured evaluation by an occupational therapist can reveal deficits that might be overseen in routine clinical examination of patients with a surgically treated LGG.

METHODS

A total of 20 patients with radiographically suspected LGG were examined in a standardized fashion at 3 stages: preoperatively, postoperatively, and 3 months thereafter. Results were analyzed descriptively.

RESULTS

A total of 19 patients (95%) showed no postoperative motor deficit; one suffered from akinesia due to supplementary motor area involvement and demonstrated a transient deficit with manifestation on the first postoperative day. Patients with eloquent LGGs, involving speech (n = 6, 30%), exhibited different transient speech disturbances according to the location of the lesion. Structured testing revealed a postoperative worsening of movement mirroring (upper extremity) and finger discrimination (sensory) in 5 of 20 patients (25%). Force meter evaluation of the upper extremity was decreased significantly postoperatively for the affected hemisphere, even though motor deficits were absent in most patients. The action research arm test detected deterioration in more than one half of the patients postoperatively. Patients recovered from these deficits within the first 3 months.

CONCLUSIONS

Routine clinical examination and neuropsychological evaluation fail to detect mild deficits in sensory function, reactivity, and apraxia, which may have a serious impact on patients' ability to return to their normal lives and work.