Is supratotal resection achievable in low-grade gliomas? Feasibility, putative factors, safety, and functional outcome

J Neurosurg 132:1692–1705, 2020

Surgery for low-grade gliomas (LGGs) aims to achieve maximal tumor removal and maintenance of patients’ functional integrity. Because extent of resection is one of the factors affecting the natural history of LGGs, surgery could be extended further than total resection toward a supratotal resection, beyond tumor borders detectable on FLAIR imaging. Supratotal resection is highly debated, mainly due to a lack of evidence of its feasibility and safety. The authors explored the intraoperative feasibility of supratotal resection and its short- and long-term impact on functional integrity in a large cohort of patients. The role of some putative factors in the achievement of supratotal resection was also studied.

METHODS Four hundred forty-nine patients with a presumptive radiological diagnosis of LGG consecutively admitted to the neurosurgical oncology service at the University of Milan over a 5-year period were enrolled. In all patients, a policy was adopted to perform surgery according to functional boundaries, aimed at achieving a supratotal resection whenever possible, without any patient or tumor a priori selection. Feasibility, general safety, and tumor or patient putative factors possibly affecting the achievement of a supratotal resection were analyzed. Postsurgical patient functional performance was evaluated in five cognitive domains (memory, language, praxis, executive functions, and fluid intelligence) using a detailed neuropsychological evaluation and quality of life (QOL) examination.

RESULTS Total resection was feasible in 40.8% of patients, and supratotal resection in 32.3%. The achievement of a supratotal versus total resection was independent of age, sex, education, tumor volume, deep extension, location, handedness, appearance of tumor border, vicinity to eloquent sites, surgical mapping time, or surgical tools applied. Supratotal resection was associated with a long clinical history and histological grade II, suggesting that reshaping of brain networks occurred. Although a consistent amount of apparently MRI-normal brain was removed with this approach, the procedure was safe and did not carry additional risk to the patient, as demonstrated by detailed neuropsychological evaluation and QOL examination. This approach also improved seizure control.

CONCLUSIONS Supratotal resection is feasible and safe in routine clinical practice. These results show that a long clinical history may be the main factor associated with its achievement.

Surgical outcomes of anterior cerebellopontine angle meningiomas using the anterior transpetrosal approach compared with the lateral suboccipital approach

Acta Neurochirurgica (2020) 162:1243–1248

Anterior transpetrosal approach (ATPA) and lateral suboccipital approach (LSO) are the major surgical approaches for cerebellopontine angle (CPA) meningiomas. Particularly, anterior CPA meningiomas are challenging lesions to be treated surgically. To date, only a few studies have directly compared the outcomes of both approaches focusing on the anterior CPA meningiomas.

Methods For the comparative analysis, anterior CPA meningiomas that were eligible for both APTA and LSO were collected in our hospital from April 2005 to March 2017. Anterior CPA meningiomas targeted for this study were defined as follows: (1) without cavernous sinus, clivus, and middle cranial fossa extension, (2) the posterior edge is 1 cm behind the posterior wall of the internal auditory canal, and (3) the inferior edge is above the jugular tuberculum. Based on these criteria, the operative outcomes of 17 patients and 13 patients who were operated via ATPA and LSO were evaluated.

Results The complication rate of the LSO group was significantly higher than that of the ATPA group (30.7% vs. 0%, p = 0.033). The removal rate did not differ between the ATPA and LSO groups (97.35% vs. 99.23%, p = 0.12). The operative time was significantly shorter in the LSO group than in the ATPA group (304.3 min vs. 405.8 min, p = 0.036).

Conclusions Although the LSO is more widely used for CPA meningiomas, ATPA is also considered for these anterior CPA meningiomas.

Petroclival meningiomas: long-term outcomes of multimodal treatments and management strategies based on 30 years of experience at a single institution

J Neurosurg 132:1675–1682, 2020

A thorough investigation of the long-term outcomes and chronological changes of multimodal treatments for petroclival meningiomas is required to establish optimal management strategies. The authors retrospectively reviewed the long-term clinical outcomes of patients with petroclival meningioma according to various treatments, including various surgical approaches, and they suggest treatment strategies based on 30 years of experience at a single institution.

METHODS Ninety-two patients with petroclival meningiomas were treated surgically at the authors’ institution from 1986 to 2015. Patient demographics, overall survival, local tumor control rates, and functional outcomes according to multimodal treatments, as well as chronological change in management strategies, were evaluated. The mean clinical and radiological follow-up periods were 121 months (range 1–368 months) and 105 months (range 1–348 months), respectively.

RESULTS A posterior transpetrosal approach was most frequently selected and was followed in 44 patients (48%); a simple retrosigmoid approach, undertaken in 30 patients, was the second most common. The initial extent of resection and following adjuvant treatment modality were classified into 3 subgroups: gross-total resection (GTR) only in 13 patients; non-GTR treatment followed by adjuvant radiosurgery or radiation therapy (non-GTR+RS/RT) in 56 patients; and non-GTR without adjuvant treatment (non-GTR only) in 23 patients. The overall progression-free survival rate was 85.8% at 5 years and 81.2% at 10 years. Progression or recurrence rates according to each subgroup were 7.7%, 12.5%, and 30.4%, respectively.

CONCLUSIONS The authors’ preferred multimodal treatment strategy, that of planned incomplete resection and subsequent adjuvant radiosurgery, is a feasible option for the management of patients with large petroclival meningiomas, considering both local tumor control and postoperative quality of life.

 

Impact of Extent of Resection on Incidence of Postoperative Complications in PatientsWith Glioblastoma

Neurosurgery 86:625–630, 2020

Extent of resection (EOR) is well established as correlating with overall survival in patients with glioblastoma (GBM). The impact of EOR on reported quality metrics such as patient safety indicators (PSIs) and hospital-acquired conditions (HACs) is unknown.

OBJECTIVE: To perform a retrospective study to evaluate possible associations between EOR and the incidence of PSIs and HACs.

METHODS: We queried all patients diagnosed with GBM who underwent surgical resection at our institution between January 2011 and May 2017. Pre- and postoperative magnetic resonance imageswere analyzed for EOR. Each chart was reviewed to determine the incidence of PSIs and HACs.

RESULTS: A total of 284 patients met the inclusion criteria. EOR ranged from 39.00 to 100%, with a median of 99.84% and a mean of 95.7%. There were 16 PSI, and 13 HAC, events. There were no significant differences in the rates of PSIs or HACs when compared between patients stratified by gross total resection (EOR ≥ 95%) and subtotal resection (EOR < 95%). The odds of encountering a PSI or HAC were 2.5 times more likely in the subtotal resection group compared to the gross total resection group (P = .58). After adjusting for confounders, the odds of encountering a PSI or HAC in the subtotal resection group were 3.9 times greater than for the gross total resection group (P < .05).

CONCLUSION: Gross total resection of GBM is associated with a decreased incidence of PSIs and HACs, as compared to subtotal resection.

Incidental Low-Grade Gliomas: Single-Institution Management Based on Clinical, Surgical, and Molecular Data

Neurosurgery 2019 DOI:10.1093/neuros/nyz114

Incidentally discovered diffuse low-grade gliomas (iLGG) are poorly documented in the literature. They are diagnosed by chance during radiological examinations.

OBJECTIVE: To review a cohort of patients with iLGG surgically treated in our institution, analyzing clinical, molecular, and surgical aspects.

METHODS: Clinical, radiological, and treatment data of iLGGwere retrieved and compared with those of symptomatic diffuse LGGs (sLGG). Histological and molecular review was carried out as well. The extent of resection was evaluated on preoperative and postoperative T2-weighted magnetic resonance imaging.

RESULTS: Thirty-four iLGG cases were identified within a monoinstitutional cohort of 332 patients operated for low-grade gliomas from 2000 to 2017. Clinically, patients with iLGG had higher preoperative karnofsky performance scale (KPS) (P = .003), smaller tumor volume (P=.0001), lower frequency of eloquent areas involvement (P=.0001), and higher rate of complete resection (P = .0001) compared to those with sLGG. No differences in the molecular profile and O6-methylguanine-DNA-methyltransferase promoter methylation were detected between iLGG and sLGG. Importantly, patients with iLGG had longer overall survival than those with sLGG (P = .0001), even when a complete surgical resection was achieved (P = .001).

CONCLUSION: Although the therapeutic strategy of iLGG is still a matter of debate, our data support the safety and the effectiveness of early surgical resection. The favorable prognosis of iLGG may be due to the higher practicability of extensive resection, noneloquent tumor location, and smaller tumor volume.

Staged Laser Interstitial Thermal Therapy (LITT) Treatments to Left Insular Low-Grade Glioma

Neurosurgery 2019 DOI:10.1093/neuros/nyz120

Low-grade insular gliomas remain challenging tumors for aggressive resection because of the numerous functional and vascular structures surrounding them. Because of the potential morbidities associated with open surgical resection, less invasive techniques may confer a more optimal balance between cytoreduction and surgical complications. For this reason, we evaluated the use of laser interstitial thermal therapy (LITT) for resection of a dominant hemisphere oligodendroglioma World Health Organization (WHO) grade II in a 68-yr-old patient by use of multiple staged surgeries for its resection.

CLINICAL PRESENTATION: Patient KK was a 68-yr-old female who was found to have a large, left-sided insular mass that was shown to be an oligodendroglioma WHO grade II, positive for codeletion 1p/19q and IDH1 mutant on biopsy. Over the course of 3 mo, KK underwent 2 stages of LITT, targeting different areas of the 5-cmtumor. The 60-d magnetic resonance imaging (MRI) demonstrated a reduction in size of the tumor from5.2×3.3×2.4 cm to 3.6 × 1.9 × 1.4 cm. She returned for a second stage targeting the anterior portion of the tumor. KK did well postoperatively and went on to postsurgical chemoradiation. At the
2-yr follow-up, the lesion showed near resolution on MRI.

CONCLUSION: This case report demonstrates successful use of LITT for staged surgeries to treat a left hemisphere-dominant insular lesion. This establishes the use of LITT as a viable, minimally invasive option to treat tumors that are difficult to access or pose concerns for increased morbidity through an open surgery.

Is Intraoperative Pathology Needed if 5-Aminolevulinic-Acid-Induced Tissue Fluorescence Is Found in Stereotactic Brain Tumor Biopsy?

Neurosurgery, Volume 86, Issue 3, March 2020, Pages 366–373

Intraoperative histopathology and acquisition of multiple tissue samples in stereotactic biopsies results in a prolonged length of surgery and potentially increased complication rate.
OBJECTIVE
To investigate the clinical benefits of a novel strategy for stereotactic brain tumor biopsies with the assistance of 5-aminolevulinic acid (5-ALA) induced fluorescence.
METHODS
Patients that received 5-ALA prior to stereotactic biopsy of a suspected brain tumor were included. According to our strategy, the procedure was terminated in the case of strong fluorescence of the biopsy samples. In contrast, intraoperative histology was demanded in the case of vague/no fluorescence. Length of surgery, number of biopsy samples, diagnostic rate, and periprocedural complications were compared between these 2 groups.
RESULTS
Altogether, 79 patients were included, and strong fluorescence was present in 62 cases (79%), vague fluorescence was in 4 cases (5%), and no fluorescence was in 13 cases (16%). The diagnostic rate was comparable in biopsies with strong fluorescence without intraoperative histopathology and cases with vague/no fluorescence with intraoperative histopathology (98% vs 100%; P = 1.000). A significantly shorter length of surgery (41 vs 77 min; P < .001) and reduced average number of biopsy samples (3.6 vs 4.9; P = .011) was found in patients with strong compared to vague/no fluorescence. However, no statically significant difference in periprocedural complications between cases with strong and vague/no fluorescence was found (7% vs 18%; P = .166).
CONCLUSION
Our data demonstrate the clinical benefits of a novel strategy for stereotactic brain tumor biopsies with assistance of 5-ALA. Thus, this biopsy strategy will increase the efficiency of this standard neurosurgical procedure in the future.

Surgical management of Tuberculum sellae Meningiomas: Myths, facts, and controversies

Acta Neurochirurgica (2020) 162:631–640

The optimal management of tuberculum sellae (TS) meningiomas, especially the surgical strategy, continues to be debated along with several controversies that persist.

Methods A task force was created by the EANS skull base section committee along with its members and other renowned experts in the field to generate recommendations for the surgical management of these tumors on a European perspective. To achieve this, the task force also reviewed in detail the literature in this field and had formal discussions within the group.

Results The constituted task force dealt with the practice patterns that exist with respect to pre-operative radiological investigations, ophthalmological and endocrinological assessments, optimal surgical strategies, and follow-up management.

Conclusion This article represents the consensually derived opinion of the task force with respect to the surgical treatment of tuberculum sellae meningiomas. Areas of uncertainty where further clinical research is required were identified.

An Online Calculator for the Prediction of Survival in Glioblastoma Patients Using Classical Statistics and Machine Learning

Neurosurgery, Volume 86, Issue 2, February 2020, Pages E184–E192

Although survival statistics in patients with glioblastoma multiforme (GBM) are well-defined at the group level, predicting individual patient survival remains challenging because of significant variation within strata.

OBJECTIVE: To compare statistical and machine learning algorithms in their ability to predict survival in GBM patients and deploy the best performing model as an online survival calculator.

METHODS: Patients undergoing an operation for a histopathologically confirmed GBM were extracted from the Surveillance Epidemiology and End Results (SEER) database (2005-2015) and split into a training and hold-out test set in an 80/20 ratio. Fifteen statistical and machine learning algorithms were trained based on 13 demographic, socioeconomic, clinical, and radiographic features to predict overall survival, 1-yr survival status, and compute personalized survival curves.

RESULTS: In total, 20 821 patients met our inclusion criteria. The accelerated failure time model demonstrated superior performance in terms of discrimination (concordance index = 0.70), calibration, interpretability, predictive applicability, and computational efficiency compared to Cox proportional hazards regression and other machine learning algorithms. This model was deployed through a free, publicly available software interface (https://cnoc-bwh.shinyapps.io/gbmsurvivalpredictor/).

CONCLUSION: The development and deployment of survival prediction tools require a multimodal assessment rather than a single metric comparison. This study provides a framework for the development of prediction tools in cancer patients, as well as an online survival calculator for patients with GBM. Future efforts should improve the interpretability, predictive applicability, and computational efficiency of existing machine learning algorithms, increase the granularity of population-based registries, and externally validate the proposed prediction tool.

A novel robot-guided minimally invasive technique for brain tumor biopsies

J Neurosurg 132:150–158, 2020

As decisions regarding tumor diagnosis and subsequent treatment are increasingly based on molecular pathology, the frequency of brain biopsies is increasing. Robotic devices overcome limitations of frame-based and frameless techniques in terms of accuracy and usability. The aim of the present study was to present a novel, minimally invasive, robot-guided biopsy technique and compare the results with those of standard burr hole biopsy.

METHODS A tubular minimally invasive instrument set was custom-designed for the iSYS-1 robot-guided biopsies. Feasibility, accuracy, duration, and outcome were compared in a consecutive series of 66 cases of robot-guided stereotactic biopsies between the minimally invasive (32 patients) and standard (34 patients) procedures.

RESULTS Application of the minimally invasive instrument set was feasible in all patients. Compared with the standard burr hole technique, accuracy was significantly higher both at entry (median 1.5 mm [range 0.2–3.2 mm] vs 1.7 mm [range 0.8–5.1 mm], p = 0.008) and at target (median 1.5 mm [range 0.4–3.4 mm] vs 2.0 mm [range 0.8–3.9 mm], p = 0.019). The incision-to-suture time was significantly shorter (median 30 minutes [range 15–50 minutes] vs 37.5 minutes [range 25–105 minutes], p < 0.001). The skin incision was significantly shorter (median 16.3 mm [range 12.7–23.4 mm] vs 28.4 mm [range 20–42.2 mm], p = 0.002). A diagnostic tissue sample was obtained in all cases.

CONCLUSIONS Application of the novel instrument set was feasible in all patients. According to the authors’ data, the minimally invasive robot-guidance procedure can significantly improve accuracy, reduce operating time, and improve the cosmetic result of stereotactic biopsies.

5-Aminolevulinic Acid Fluorescence-Guided Resection of 18F-FET-PET Positive Tumor Beyond Gadolinium Enhancing Tumor Improves Survival in Glioblastoma

Neurosurgery 85:E1020–E1029, 2019

The value of early postoperative 18F-FET-PET in patients with glioblastoma (GBM) is unclear. Five-aminolevulinic acid (5-ALA) is used for fluorescence-guided resections in these patients and previous data suggest that fluorescence and 18F-FET-PET both demarcate larger tumor volumes than gadolinium enhanced magnet resonance imaging (MRI).

OBJECTIVE: To correlate fluorescence with enhancing volumes on postoperative MRI and 18F-FET-PET tumor volumes, and determine the value of postoperative 18F-FET-PET for predicting survival through observational study.

METHODS: GBM patients underwent fluorescence-guided resection after administration of 5-ALA followed by early postoperative MRI and 18F-FET-PET for determination of residual tissue volumes. All patients were treated with standard temozolomide radiochemotherapy and monitored for progression-free and overall survival (PFS, OS).

RESULTS: A total of 31 patients were included. For functional reasons, residual 5-ALA derived fluorescent tissue was left unresected in 18 patients with a median 18F-FETPET volume of 17.82 cm3 (interquartile range 6.50-29.19). In patients without residual fluorescence, median 18F-FET-PET volume was 1.20 cm3 (interquartile range 0.87-5.50) and complete resection of gadolinium enhancing tumor was observed in 100% of patients. A 18F-FET-PET volume of above 4.3 cm3 was associated with worse OS (logrank P-value≤.05), also in patients with no residual contrast enhancing tumor on MRI. More patients in whom fluorescencing tissue had been removed completely had postoperative 18F-FET-PET tumor volumes below 4.3 cm3.

CONCLUSION: Postoperative 18F-FET-PET volumes predict OS and PFS. Resection of 5-ALA derived fluorescence beyond gadolinium enhancing tumor tissue leads to lower postoperative 18F-FET-PET tumor volumes and improved OS and PFS without additional deficits.

Upfront Magnetic Resonance Imaging-Guided Stereotactic Laser-Ablation in Newly Diagnosed Glioblastoma: A Multicenter Review of Survival Outcomes Compared to a Matched Cohort of Biopsy-Only Patients

Neurosurgery. 2019 Dec 1;85(6):762-772

Laser ablation (LA) is used as an upfront treatment in patients with deep seated newly diagnosed Glioblastoma (nGBM).

OBJECTIVE: To evaluate the outcomes of LA in patients with nGBM and compare them with a matched biopsy-only cohort.

METHODS: Twenty-four nGBM patients underwent upfront LA at Cleveland clinic, Washington University in St. Louis, and Yale University (6/2011-12/2014) followed by chemo/radiotherapy. Also, 24 out of 171 nGBM patients with biopsy followed by chemo/radiotherapy were matched based on age (< 70 vs ≥ 70), gender, tumor location (deep vs lobar), and volume (<11 cc vs ≥11 cc). Progression-free survival (PFS), overall survival (OS), and disease-specific PFS and OS were outcome measures. Three prognostic groups were identified based on extent of tumor ablation by thermal-damage-threshold (TDT)-lines.

RESULTS: The median tumor volume in LA (n = 24) and biopsy only (n = 24) groups was 9.3 cm3 and 8.2 cm3 respectively. Overall, median estimate of OS and PFS in LA cohort was 14.4 and 4.3 mo compared to 15.8 mo and 5.9 mo for biopsy only cohort. On multivariate analysis, favorable TDT-line prognostic groups were associated with lower incidence of disease specific death (P = .03) and progression (P = .05) compared to other groups including biopsy only cohort. Only age (<70 yr, P=.02) and tumor volume (<11 cc, P=.03) were favorable prognostic factors for OS.

CONCLUSION: Themaximum tumor coverage by LA followed by radiation/chemotherapy is an effective treatment modality in patientswith nGBM, compared to biopsy only cohort. The TDT-line prognostic groups were independent predictor of disease specific death and progression after LA.

Risk factors associated with postoperative recurrence in atypical intracranial meningioma

Acta Neurochirurgica (2019) 161:2563–2570

Atypical meningioma (AM) has a high rate of local recurrence after surgery, and the role of adjuvant radiotherapy in AM remains controversial. We analysed progression-free survival (PFS) and identified the factors associated with postoperative recurrence in AM patients.

Methods Data were obtained from 263 AM patients who underwent surgery at our institution between October 2009 and September 2018. Analyses included factors such as the extent of surgical resection, MIB-1 labelling index, brain invasion and therapy modality. Univariate and multivariate analyses were used to assess recurrence-related prognostic factors.

Result The median follow-up duration was 41 months, and the median PFS was 28 months. Gross total resection (GTR) was achieved in 213 (81.0%) patients, and 86 (32.7%) patients received postoperative radiation therapy (RT). During follow-up, there were 61 (23.2%) tumour recurrences. In a Cox multivariate analysis, MIB-1 labelling index (hazard ratio = 2.637; p < 0.001), secondary tumour (hazard ratio = 3.541; p < 0.001), tumour size (hazard ratio = 1.818; p = 0.032) and extent of resection (hazard ratio = 2.861; p < 0.001) were independent significant predictors of tumour recurrence. RTwas associated with reduced tumour recurrence in subtotal resection (STR) (p = 0.023) but not GTR (p = 0.923). An analysis of 6 meningioma patients who underwent more than 3 operations suggested that the recurrence time became shorter and the MIB-1 labelling index increased as the number of recurrences increased.

Conclusions MIB-1 labelling index, secondary tumour, tumour size and extent of resection were powerful predictors of recurrence in AM patients. Postoperative RT did not decrease the risk of recurrence in GTR patients.

Prospective clinical validation of a meningioma consistency grading scheme

J Neurosurg 131:1356–1360, 2019

The present study aims to assess the clinical utility of a previously validated intraoperative meningioma consistency grading scale and its association with extent of resection (EOR) and various surgical outcomes.

METHODS The previously validated grading system was prospectively assessed in 127 consecutive patients undergoing open craniotomy for meningioma by multiple neurosurgeons at two high-volume academic hospitals from 2013 to 2016. Consistency grading scores ranging from 1 (soft) to 5 (firm/calcified) were retrospectively analyzed to test for association with surgical outcomes and EOR, categorized as gross-total resection (GTR) or subtotal resection, defined by postoperative MRI.

RESULTS One hundred twenty-seven patients were included in the analysis with a tumor consistency distribution as follows: grade 1, 3.1%; grade 2, 14.2%; grade 3, 44.1%; grade 4, 32.3%; and grade 5, 6.3%. The mean tumor diameter was 3.6 ± 1.7 cm. Tumor consistency grades were grouped into soft (grades 1 and 2), average (grade 3), and firm (grades 4 and 5) groups for statistical analysis with distributions of 17.3%, 44.1%, and 38.6%, respectively. There was no association between meningioma consistency and maximal tumor diameter, or location. Mean duration of surgery was longer for tumors with higher consistency: grades 1 and 2, 186 minutes; grade 3, 219 minutes; and grades 4 and 5, 299 minutes (p = 0.000028). There was a trend toward higher perioperative complication rates for tumors of increased consistency: grades 1 and 2, 4.5%; grade 3, 7.0%; and grades 4 and 5, 20.8% (p = 0.047). The proportion of GTR for each consistency group was as follows: grades 1 and 2, 77%; grade 3, 68%; and grades 4 and 5, 43% (p = 0.0062).

CONCLUSIONS In addition to other important meningioma characteristics such as invasiveness, tumor consistency is a key determinant of surgical outcomes, including operative duration and EOR. Future studies predicting tumor consistency based on preoperative neuroimaging will help considerably with preoperative planning for meningiomas.

 

Comparative Analysis of Subventricular Zone Glioblastoma Contact and Ventricular Entry During Resection in Predicting Dissemination, Hydrocephalus, and Survival

Neurosurgery, Volume 85, Issue 5, November 2019, Pages E924–E932

Ventricular entry during glioblastoma resection and tumor contact with the subventricular zone (SVZ) have both been shown to associate with development of hydrocephalus, leptomeningeal dissemination, distant parenchymal recurrence, and decreased survival. However, prior studies did not analyze these variables together in a single-patient population; therefore, it is unknown which is an independent predictor of these outcomes.

OBJECTIVE: To conduct a comparative outcome analysis of surgical ventricular entry and SVZ contact by glioblastoma in a retrospective cohort of 232 patients.

METHODS: Outcomes studied included hydrocephalus, leptomeningeal dissemination, distant tumor recurrences, and progression-free (PFS) and overall (OS) survival. The Cox proportional regression analyses were adjusted for age at diagnosis, preoperative Karnofsky performance status score, extent of resection, temozolomide and radiation treatments, and tumor molecular status (specifically, IDH1/2 mutation and MGMT promoter methylation).

RESULTS: Surgical ventricular entry, SVZ-contacting glioblastoma, hydrocephalus, leptomeningeal dissemination, and distant recurrences were observed in 85 (36.6%), 114 (49.1%), 19 (8.2%), 78 (33.6%), and 59 (25.4%) patients, respectively. Multivariate, adjusted analysis revealed SVZ tumor contact—but not ventricular entry—associated with hydrocephalus (hazard ratio, HR, 4.20 [1.13-15.7], P = .03), leptomeningeal dissemination (HR 1.93 [1.14-3.28], P = .01), PFS (HR 2.10 [1.53-2.88], P < .001), and OS (HR 1.90 [1.35-2.67], P < .001). Distant recurrences were not associated with either. No interaction between the 2 variables was statistically noted.

CONCLUSION: SVZ contact by glioblastoma was independently associated with the development of hydrocephalus, leptomeningeal dissemination, and decreased survival. SVZ tumor contact was associated with ventricular entry during surgical resections, which did not independently correlate with these outcomes.

Growth prediction in asymptomatic meningiomas: the utility of the AIMSS score

Acta Neurochirurgica (2019) 161:2233–2240

Management of asymptomatic meningiomas represents a challenge due to the absence of a solid consensus on which is the best management strategy. There are various known factors predicting meningiomas growth risk. However, the Asian Intracranial Meningioma Scoring System (AIMSS) is the only described score to quantify such risk thus emerging as a potential tool for management decisions. This study aims to validate this score on our series of asymptomatic meningiomas.

Method We performed a retrospective review of asymptomatic meningiomas diagnosed at our institution between January 2008 and October 2016 and followed by an annual cerebral Magnetic Resonance Imaging (MRI). For each lesion, the AIMSS score was calculated thus classifying them in low (0–2), intermediate (3–6) or high risk (7–11) of rapid growth (>2cm 3 /year). We investigated the correlation between the expected Average Growth Rate (AGR) according to the score and the one obtained in our study. The mean growth velocity over the different risk groups was also compared.

Results Overall, 69 asymptomatic meningiomas found incidentally in 46 patients were included in the study; 31 were assigned to the low-risk group, 34 to the intermediate-risk group and 4 to the high-risk group. Attending to the AGR, 0% showed rapid growth in the low-risk group, 12% in the intermediate-risk group, and 25% in the high-risk group. The mean growth velocity showed a significant difference over the different risk groups (p < 0,001).

Conclusions According to our finding, the AIMSS score is a valid tool to estimate the risk of rapid growth of asymptomatic meningiomas. It is especially useful distinguishing between low- and intermediate-risk meningiomas. This feature would allow physicians to adjust the periodicity of radiological and clinical controls. Adding more known risk factors of rapid growth to the score might improve its predictive capabilities with the high-risk group.

Surgical outcomes after reoperation for recurrent non–skull base meningiomas

J Neurosurg 131:1179–1187, 2019

Recurrent meningiomas are primarily managed with radiation therapy or repeat resection. Surgical morbidity after reoperation for recurrent meningiomas is poorly understood. Thus, the objective of this study was to report surgical outcomes after reoperation for recurrent non–skull base meningiomas.

METHODS A retrospective review of patients was performed. Inclusion criteria were patients with recurrent meningioma who had prior resection and supratentorial non–skull base location. Univariate and multivariate logistic regression and recursive partitioning analysis were used to identify risk factors for surgical complications.

RESULTS The authors identified 67 patients who underwent 111 reoperations for recurrent supratentorial non–skull base meningiomas. The median age was 53 years, 49% were female, and the median follow-up was 9.8 years. The most common presenting symptoms were headache, weakness, and seizure. The WHO grade after the last reoperation was grade I in 22% of cases, grade II in 51%, and grade III in 27%. The tumor grade increased at reoperation in 22% of cases. Tumors were located on the convexity (52%), parasagittal (33%), falx (31%), and multifocal (19%) locations. Tumors involved the middle third of the sagittal plane in 52% of cases. In the 111 reoperations, 48 complications occurred in 32 patients (48%). There were 26 (54%) complications requiring surgical intervention. There was no perioperative mortality. Complications included neurological deficits (14% total, 8% permanent), wound dehiscence/infection (14%), and CSF leak/pseudomeningocele/hydrocephalus (9%). Tumors that involved the middle third of the sagittal plane (OR 6.97, 95% CI 1.5–32.0, p = 0.006) and presentation with cognitive changes (OR 20.7, 95% CI 2.3–182.7, p = 0.001) were significantly associated with complication occurrence on multivariate analysis. The median survival after the first reoperation was 11.5 years, and the 2-, 5-, and 10-year Kaplan-Meier survival rates were 91.0%, 68.8%, and 50.0%, respectively.

CONCLUSIONS Reoperation for recurrent supratentorial non–skull base meningioma is associated with a high rate of complications. Patients with cognitive changes and tumors that overlap the middle third of the sagittal plane are at increased risk of complications. Nevertheless, excellent long-term survival can be achieved without perioperative mortality.

Transcortical insular glioma resection: clinical outcome and predictors

J Neurosurg 131:706–716, 2019

Insular lobe gliomas continue to challenge neurosurgeons due to their complex anatomical position. Transcortical and transsylvian corridors remain the primary approaches for reaching the insula, but the adoption of one technique over the other remains controversial. The authors analyzed the transcortical approach of resecting insular gliomas in the context of patient tumor location based on the Berger-Sinai classification, achievable extents of resection (EORs), overall survival (OS), and postsurgical neurological outcome.

METHODS The authors studied 255 consecutive cases of insular gliomas that underwent transcortical tumor resection in their division. Tumor molecular pathology, location, EOR, postoperative neurological outcome for each insular zone, and the accompanying OS were incorporated into the analysis to determine the value of this surgical approach.

RESULTS Lower-grade insular gliomas (LGGs) were more prevalent (63.14%). Regarding location, giant tumors (involving all insular zones) were most prevalent (58.82%) followed by zone I+IV (anterior) tumors (20.39%). In LGGs, tumor location was an independent predictor of survival (p = 0.003), with giant tumors demonstrating shortest patient survival (p = 0.003). Isocitrate dehydrogenase 1 (IDH1) mutation was more likely to be associated with giant tumors (p < 0.001) than focal tumors located in a regional zone. EOR correlated with survival in both LGG (p = 0.001) and higher-grade glioma (HGG) patients (p = 0.008). The highest EORs were achieved in anterior-zone LGGs (p = 0.024). In terms of developing postoperative neurological deficits, patients with giant tumors were more susceptible (p = 0.038). Postoperative transient neurological deficit was recorded in 12.79%, and permanent deficit in 15.70% of patients. Patients who developed either transient or permanent postsurgical neurological deficits exhibited poorer survival (p < 0.001).

CONCLUSIONS The transcortical surgical approach can achieve maximal tumor resection in all insular zones. In addition, the incorporation of adjunct technologies such as multimodal brain imaging and mapping of cortical and subcortical eloquent brain regions into the transcortical approach favors postoperative neurological outcomes, and prolongs patient survival.

Comparison of Motor Outcome in Patients Undergoing Awake vs General Anesthesia Surgery for Brain Tumors Located Within or Adjacent to the Motor Pathways

Neurosurgery, Volume 85, Issue 3, September 2019: E470–E476

Surgical removal of intra-axial brain tumors aims at maximal tumor resection while preserving function. The potential benefit of awake craniotomy over craniotomy under general anesthesia (GA) for motor preservation is yet unknown.

OBJECTIVE: To compare the clinical outcomes of patients who underwent surgery for perirolandic tumors while either awake or under GA.

METHODS: Between 2004 and 2015, 1126 patients underwent surgical resection of newly diagnosed intra-axial tumors in a single institution. Data from 85 patients (44 awake, 41 GA) with full dataset who underwent resections for perirolandic tumors were retrospectively analyzed.

RESULTS: Identification of the motor cortex required significantly higher stimulation thresholds in anesthetized patients (9.1 ± 4 vs 6.2 ± 2.7 mA for awake patients, P = .0008). There was no group difference in the subcortical threshold for motor response used to assess the proximity of the lesion to the corticospinal (pyramidal) tract. High-grade gliomas were the most commonly treated pathology. The extent of resection and residual tumor volume were not different between groups. Postoperative motor deficits were more common in the anesthetized patients at 1 wk (P = .046), but no difference between the groups was detected at 3 mo. Patients in the GA group had a longer mean length of hospitalization (10.3 vs 6.7 d for the awake group, P = .003).

CONCLUSION: Awake craniotomy results in a better early postoperative motor outcome and shorter hospitalization compared with patients who underwent the same surgery under GA. The finding of higher cortical thresholds for the identification of the motor cortex in anesthetized patients may suggest an inhibitory effect of anesthetic agents on motor function.

Elucidating the kinetics of sodium fluorescein for fluorescence-guided surgery of glioma

J Neurosurg 131:724–734, 2019

The use of the optical contrast agent sodium fluorescein (NaFl) to guide resection of gliomas has been under investigation for decades. Although this imaging strategy assumes the agent remains confined to the vasculature except in regions of blood-brain barrier (BBB) disruption, clinical studies have reported significant NaFl signal in normal brain tissue, limiting tumor-to-normal contrast. A possible explanation arises from earlier studies, which reported that NaFl exists in both pure and protein-bound forms in the blood, the former being small enough to cross the BBB. This study aims to elucidate the kinetic binding behavior of NaFl in circulating blood and its effect on NaFl accumulation in brain tissue and tumor contrast. Additionally, the authors examined the blood and tissue kinetics, as well as tumor uptake, of a pegylated form of fluorescein selected as a potential optical analog of gadolinium-based MRI contrast agents.

METHODS Cohorts of mice were administered one of the following doses/forms of NaFl: 1) high human equivalent dose (HED) of NaFl, 2) low HED of NaFl, or 3) pegylated form of fluorescein. In each cohort, groups of animals were euthanized 15, 30, 60, and 120 minutes after administration for ex vivo analysis of fluorescein fluorescence. Using gel electrophoresis and fluorescence imaging of blood and brain specimens, the authors quantified the temporal kinetics of bound NaFl, unbound NaFl, and pegylated fluorescein in the blood and normal brain tissue. Finally, they compared tumor-to-normal contrast for NaFl and pegylated-fluorescein in U251 glioma xenografts.

RESULTS Administration of NaFl resulted in the presence of unbound and protein-bound NaFl in the circulation, with unbound NaFl constituting up to 70% of the signal. While protein-bound NaFl was undetectable in brain tissue, unbound NaFl was observed throughout the brain. The observed behavior was time and dose dependent. The pegylated form of fluorescein showed minimal uptake in brain tissue and improved tumor-to-normal contrast by 38%.

CONCLUSIONS Unbound NaFl in the blood crosses the BBB, limiting the achievable tumor-to-normal contrast and undermining the inherent advantage of tumor imaging in the brain. Dosing and incubation time should be considered carefully for NaFl-based fluorescence-guided surgery (FGS) of glioma. A pegylated form of fluorescein showed more favorable normal tissue kinetics that translated to higher tumor-to-normal contrast. These results warrant further development of pegylated-fluorescein for FGS of glioma.