Vascular anomalies in patients with growth hormone-secreting pituitary adenomas: illustrative case report and systematic review of the literature.

PURPOSE: Endonasal resection is the first-line treatment for patients harboring growth hormone (GH)-secreting pituitary adenomas. The complexity of the parasellar neurovascular structures makes pre-operative diagnostic imaging essential to understanding the anatomy of this region. We aimed to describe vascular anomalies in acromegalic patients and emphasize their relevance for surgery and preoperative planning. METHODS: A systematic review following the PRISMA statement was performed in July 2021. RESULTS: Thirty-three studies were evaluated. Elevated GH and insulin-like growth factor-1 (IGF-1) levels are linked to the occurrence of cardiovascular risk factors. This is attributed to endothelial dysfunction, mainly caused by changes in flow-mediated dilatation (FMD), which is probably the main cause of vascular anomalies in acromegaly. The occurrence of protrusions of the internal carotid artery (ICA) (35-53%), a narrow intercarotid distance, and an asymmetrical course was described. In 13-18% of acromegalic patients, the presence of an intracerebral aneurysm could be reported (incidence in the general population:0.8-1.3%). The selected studies were however performed with a small patient sample (range:1-257). We present a case report of a 57y/o male patient with anomalies of the ICA ("kissing carotid arteries") harboring a GH-secreting adenoma, which was resected via an endoscopic endonasal approach. CONCLUSIONS: There is an association between acromegaly and endothelial dysfunction, which increases cardiovascular risk factors and vascular anomalies. Preoperative vascular imaging, e.g., CT angiography, should be implemented as a standard to identify patients at risk and estimate surgical morbidity. However, no evidence-based recommendations exist so far, so future studies are necessary.

Applicability of contemporary quality indicators in vestibular surgery-do they accurately measure tumor inherent postoperative complications of vestibular schwannomas?

BACKGROUND: Due to rising costs in health care delivery, reimbursement decisions have progressively been based on quality measures. Such quality indicators have been developed for neurosurgical procedures, collectively. We aimed to evaluate their applicability in patients that underwent surgery for vestibular schwannoma and to identify potential new disease-specific quality indicators. METHODS: One hundred and three patients operated due to vestibular schwannoma were subject to analysis. The primary outcomes of interest were 30-day and 90-day reoperation, readmission, mortality, nosocomial infection and surgical site infection (SSI) rates, postoperative cerebral spinal fluid (CSF) leak, facial, and hearing function. The secondary aim was the identification of prognostic factors for the mentioned primary outcomes. RESULTS: Thirty-day (90-days) outcomes in terms of reoperation were 10.7% (14.6%), readmission 9.7% (13.6%), mortality 1% (1%), nosocomial infection 5.8%, and SSI 1% (1%). A 30- versus 90-day outcome in terms of CSF leak were 6.8% vs. 10.7%, new facial nerve palsy 16.5% vs. 6.1%. Hearing impairment from serviceable to non-serviceable hearing was 6.8% at both 30- and 90-day outcome. The degree of tumor extension has a significant impact on reoperation (p < 0.001), infection (p = 0.015), postoperative hemorrhage (p < 0.001), and postoperative hearing loss (p = 0.026). CONCLUSIONS: Our data demonstrate the importance of entity-specific quality measurements being applied even after 30 days. We identified the occurrence of a CSF leak within 90 days postoperatively, new persistent facial nerve palsy still present 90 days postoperatively, and persisting postoperative hearing impairment to non-serviceable hearing as potential new quality measurement variables for patients undergoing surgery for vestibular schwannoma.

Conventional and advanced imaging throughout the cycle of care of gliomas.

Although imaging of gliomas has evolved tremendously over the last decades, published techniques and protocols are not always implemented into clinical practice. Furthermore, most of the published literature focuses on specific timepoints in glioma management. This article reviews the current literature on conventional and advanced imaging techniques and chronologically outlines their practical relevance for the clinical management of gliomas throughout the cycle of care. Relevant articles were located through the Pubmed/Medline database and included in this review. Interpretation of conventional and advanced imaging techniques is crucial along the entire process of glioma care, from diagnosis to follow-up. In addition to the described currently existing techniques, we expect deep learning or machine learning approaches to assist each step of glioma management through tumor segmentation, radiogenomics, prognostication, and characterization of pseudoprogression. Thorough knowledge of the specific performance, possibilities, and limitations of each imaging modality is key for their adequate use in glioma management.

Evaluation of 311 contemporary cases of stereotactic biopsies in patients with neoplastic and non-neoplastic lesions-diagnostic yield and management of non-diagnostic cases.

Stereotactic biopsies are an established tool for obtaining diagnosis of unclear brain lesions. However, non-diagnostic biopsies still occur. We aimed to analyze the contemporary diagnostic yield of stereotactic biopsies, predictors for non-diagnostic biopsies, outcome, and follow-up strategy after non-diagnostic biopsy. We conducted a single-center retrospective study of 311 adult patients undergoing stereotactic biopsies due to a newly diagnosed lesion at our department between 2012 and 2018. Patient data regarding comorbidities, presenting symptoms, imaging features, and non-invasive diagnostic procedures were obtained. The overall diagnostic yield was 86.2% and differed significantly between the various suspected diagnosis groups and was the highest when suspecting primary brain tumor compared with non-neoplastic lesions (91.2% vs. 73.3%, p > 0.001). Predicators for non-diagnostic biopsies were small lesion size, lack of contrast-enhancement, presence of sepsis, or underlying hemato-oncological disease. In case of non-diagnostic biopsy, a re-biopsy was performed in 12 cases, revealing a final diagnosis in 75%. In 16 cases, empiric therapy was started based on the suspected underlying disease. Close follow-up was performed in the remaining 15 cases. We showed that stereotactic biopsy is a safe procedure with reasonable diagnostic yield even for non-neoplastic lesions, when non-invasive diagnostic was inconclusive. In addition, we developed treatment recommendations for cases of non-diagnostic biopsies.

Virtual reality-based evaluation of neurovascular conflict for the surgical planning of microvascular decompression in trigeminal neuralgia patients.

OBJECTIVE: Trigeminal neuralgia (TN) is a lightning bolt of violent, electrifying, and stinging pain, often secondary to the neurovascular conflict (NVC). The vessels involved in NVC are mostly arteries and rarely veins. Evaluation of NVC in the deep infratentorial region is inseparably connected with cranial imaging. We retrospectively analyzed the potential influence of three-dimensional (3D) virtual reality (VR) reconstructions compared to conventional magnetic resonance imaging (MRI) scans on the evaluation of NVC for the surgical planning of microvascular decompression in patients with TN. METHODS: Medical files were retrospectively analyzed regarding patient- and disease-related data. Preoperative MRI scans were retrospectively visualized via VR software to detect the characteristics of NVC. A questionnaire of experienced neurosurgeons evaluated the influence of VR visualization technique on identification of anatomical structures involved in NVC and on surgical strategy. RESULTS: Twenty-four patients were included and 480 answer sheets were evaluated. Compared to conventional MRI, image presentation using 3D-VR modality significantly influenced the identification of the affected trigeminal nerve (p = 0.004), the vascular structure involved in the NVC (p = 0.0002), and the affected side of the trigeminal nerve (p = 0.005). CONCLUSIONS: In patients with TN caused by NVC, the reconstruction of conventional preoperative MRI scans and the spatial and anatomical presentation in 3D-VR models offers the possibility of increased understanding of the anatomy and even more the underlying pathology, and thus influences operation planning and strategy.

Load-Bearing Capacity and Design Advantages of a Custom-Made, Thin Pure-Titanium Cranioplasty (CranioTop).

BACKGROUND: Adequate and stable coverage of cranial contour and continuity defects of any origin is a common challenge in neurosurgical clinics. This study presents the results of investigations concerning the mechanical load-bearing capacity and design advantages of custom-made implants made from a thin, pure-titanium sheet (CranioTop) (CLinstruments, Attendorn, Germany) for covering complex cranial defects. METHODS: In 9 test series, the stability of three differently shaped and sized thin titanium sheet implants was tested using vertical, uniaxial compression with 3 different compression stamps, to investigate the behaviour of these implants in relation to punctiform as well as planar forces. RESULTS: All 9 model implants showed elastic behavior in the synchronously recorded force/displacement diagrams at an impression of up to 2 mm. The forces at 2 mm deformation were between 170.1 and 702.7 Newton. CONCLUSION: Cranioplasty using CranioTop is a stable procedure for covering skull defects, even those of large dimensions. An added advantage is the significant reduction in effort required to prepare the area of the bone margins compared to other current techniques of cranioplasty.

Validating a new generation filter system for visualizing 5-ALA-induced PpIX fluorescence in malignant glioma surgery: a proof of principle study.

BACKGROUND: The BLUE 400 filter system (Carl Zeiss Meditec, Oberkochen, Germany) has provided visualization of 5-ALA-induced fluorescence-guided surgery for more than 20 years. Nevertheless, constraints, e.g., limited background discrimination during hemostasis, obstruct fluency of surgery. A novel filter with improved background visualization was developed, requiring validation regarding fluorescence discrimination. The aim of this article is to determine diagnostic accuracy and perception of protoporphyrin IX (PpIX) discrimination of a novel filter system with higher background illumination (BLUE 400 AR) compared with the gold standard, BLUE 400. METHODS: A surgical microscope equipped with both BLUE 400 and BLUE 400 AR was used. Comparisons were performed on a biological basis and on the visual perception of margins. High-resolution images were compared during and after surgery by senior neurosurgeons. In a predefined biopsy algorithm, four biopsies per patient at tumor margins of PpIX fluorescence and adjacent brain were acquired using BLUE 400 AR only from regions intended for resection and assessed for cell count and density. RESULTS: Thirty-two patients with malignant gliomas were included in this study. BLUE 400 AR markedly enhanced the brightness of the surgical field, allowing superior discrimination of brain anatomy. A total of 128 biopsies from fluorescence margins were collected. Positive predictive value (PPV) was 98.44% (95% CI, 90.06-99.77%) for malignant glioma. Residual median cell density in non-fluorescent tissue was 13% (IQR 13 to 31). Perception of the location of fluorescent margins on HD images was equivalent for both filter combinations. CONCLUSIONS: BLUE 400 AR demonstrated superior background compared with conventional BLUE 400 in malignant glioma surgery but comparable fluorescence margins and PPV. Therefore, BLUE 400 AR can be considered safe and effective in supporting malignant glioma surgery.

The rise of quality indicators in neurosurgery: 30-day unplanned reoperation rate evaluated in 3760 patients-a single-center experience.

OBJECTIVE: Quality indicators are emerging as tools to evaluate health care outcomes. Few studies have evaluated indicators suitable for neurosurgery so far. Among others, reoperation rate has been suggested as a possible indicator. We aimed to evaluate the reoperation rate in a large neurosurgery adult collective. METHODS: In this exploratory post hoc analysis, we evaluated all patients operated in our service for elective and emergency surgery between January 2014 and May 2016. Planned and unplanned reoperations were filtered and a quantitative analysis, including uni- and multivariate analyses, was performed. RESULTS: A total of 3760 patients were included in this evaluation. From 378 reoperated patients within 30 days (10.1%), 51 underwent planned procedures (1.4%). Three hundred twenty-seven patients (8.7%) represented the analyzed collective of patients having undergone unplanned surgical procedures, causing a total of 409 from 4268 additional procedures (9.6%). Early unplanned 7-day reoperation rate was 4.5% (n = 193), occurring in 4.5% of patients (n = 193). Postoperative hemorrhage (n = 107, 26.2%) and external ventricle drainage-associated infections or dislocation (n = 105, 25.7 %) were the most common indication for unplanned surgery. CONCLUSION: Unplanned re-operation rate of a neurosurgical service can help to internally evaluate health care outcome and improve quality of care. Benchmarking with this indicator however is not recommendable as results can vary distinctly due to the heterogenic patient collective of each institution. We expect unplanned reoperation rates to be higher in large university hospitals and tertiary centers with complex cases, as compared to center with less complex cases treating patients with lower morbidity. In this study, we deliver an authentic portrait of a large neurosurgical center in Germany.

The 30-day readmission rate in neurosurgery-a useful indicator for quality assessment?

BACKGROUND: A shift in how we evaluate healthcare outcomes has driven the introduction of quality indicators as potential parameters to evaluate value-based healthcare delivery. So far, only few studies have been performed evaluating quality indicators in the context of neurosurgery, especially in the European region. The purpose of this study was to evaluate the 30-day readmission rate, identify reasons for readmission regarding the various neurosurgical diagnoses, and discuss the usefulness of this rate as a potential quality indicator. METHODS: During a 6-year period, a total of 8878 hospitalized patients in our neurosurgical department were retrospectively analyzed and included in this study. Reasons for readmission were identified. Patients' diagnoses and baseline characteristics were obtained in order to identify possible risk factors for readmission. RESULTS: The 30-day readmission rate was 2.9%. The most common reason for unplanned readmissions were surgical site infections. The reasons for readmissions varied significantly between the different underlying neurosurgical diseases (p < 0.001). Multivariate logistic regression revealed hydrocephalus (OR, 4) and shorter length of stay during index admission (OR, 0.9) as risk factors for readmission. CONCLUSIONS: We provided an analysis of reasons for readmission for various neurosurgical diseases in a large patient spectrum in Germany. Although readmission rates are easy to track and an attractive tool for quality assessment, the rate alone cannot be seen as an adequate measure for quality in neurosurgery as it lacks a homogenous definition and depends on the underlying health care system. In addition, strategies for risk adjustment are required.

Real-time in vivo kinetics of protoporphyrin IX after administration of 5-aminolevulinic acid in meningiomas and comparative analyses with glioblastomas.

BACKGROUND: The usefulness of 5-aminolevulinic acid (5-ALA)-mediated fluorescence-guided surgery (FGS) in meningiomas is intensely discussed. However, data about kinetics of 5-ALA and protoporphyrin (Pp) IX in meningiomas are lacking. METHODS: As the first study so far, we performed longitudinal intraoperative real-time ex situ measurements of fluorescence intensity and PpIX concentrations during FGS of ten benign and two atypical meningiomas. Kinetics were subsequently compared with data from 229 glioblastomas. RESULTS: Spectroscopy revealed fluorescence (median 2945.65 a.u.) and PpIX accumulation (median 18.31 µg/ml) in all 43 analyzed samples. Fluorescence intensity (2961.50 a.u. vs 118.41 a.u.; p < .001) and PpIX concentrations (18.72 µg/ml vs .98 µg/ml; p < .001) were higher in samples with (N = 30) than without (N = 2) visible intraoperative tumor fluorescence. ROC curve analyses revealed a PpIX cut-off concentration of 3.85 µg/ml (AUC = .992, p = .005) and a quantitative fluorescence cut-off intensity of 286.73 a.u. (AUC = .983, p = .006) for intraoperative visible tumor fluorescence. Neither fluorescence intensity (p = .356) nor PpIX (p = .631) differed between atypical and benign meningiomas. Fluorescence and PpIX peaked 7-8 h following administration of 5-ALA. Meningiomas displayed a higher fluorescence intensity (p = .012) and PpIX concentration (p = .005) than glioblastomas 5-6 h after administration of 5-ALA. Although fluorescence was basically maintained, PpIX appeared to be cleared faster in meningiomas than in glioblastomas. CONCLUSIONS: Kinetics of PpIX and fluorescence intensity differ between meningiomas and glioblastomas in the early phase after 5-ALA administration. Modification of the timing of drug administration might impact visibility of intraoperative fluorescence and helpfulness of FGS and should be investigated in future analyses.

Maximizing safe resections: the roles of 5-aminolevulinic acid and intraoperative MR imaging in glioma surgery-review of the literature.

Malignant glioma surgery involves the challenge of preserving the neurological status of patients harboring these lesions while pursuing a maximal tumor resection, which is correlated with overall and progression-free survival. Presently, several tools exist for assisting neurosurgeons in visualizing malignant tissue. Fluorescence-guided surgery (FGS) with 5-aminolevulinic acid (5-ALA) has increasingly been used during the last decade for identifying malignant glioma. Intraoperative magnetic resonance imaging (iMRI), first introduced in the mid-1990s, is being evaluated as a further tool to maximize the extent of resection. We aimed to evaluate the literature and discuss synergies and differences between FGS with 5-ALA and iMRI. We conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. After excluding non-relevant articles, 16 articles were evaluated and included in the qualitative analysis, comprising 2 (n = 2) reviews of the literatures, 1 (n = 1) book chapter, and 13 (n = 13) clinical articles. ALA-induced fluorescence goes beyond the borders of gadolinium contrast enhancement. Several studies stress the synergy between both tools, enabling increase in extent of resection. We point out advantages of combining both methods. iMRI, however, is not widely available, is expensive, and is not recommended as sole resection control tool in high-grade glioma. For these centers, FGS together with mapping and monitoring techniques, neuronavigation and, when needed, intraoperative ultrasound provides an excellent setting for achieving state-of-the-art gross total resection of high-grade gliomas.

Spectroscopic measurement of 5-ALA-induced intracellular protoporphyrin IX in pediatric brain tumors.

OBJECTIVE: 5-Aminolevulinic acid (5-ALA)-guided resection of gliomas in adults enables better delineation between tumor and normal brain, allowing improved resection and improved patients' outcome. Recently, several reports were published regarding 5-ALA for resection of pediatric brain tumors. The aim of the study was to determine the intracellular fluorescence of protoporphyrin IX (PPIX) in pediatric brain tumors by hyperspectral imaging and to compare it with visually observed intraoperative fluorescence. METHODS: 5-ALA was administered orally 4 h prior to surgery. During tumor resection, the surgeon assessed the fluorescence signal to be strong, weak, or absent. Subsequently, fluorescence intensity of tumor samples was measured via spectroscopy. In addition, clinical data, imaging, and laboratory data were analyzed. RESULTS: Eleven children (1-16 years) were operated. Tumor entities included three (n = 3) medulloblastomas, two (n = 2) pilocytic astrocytomas (PA), two (n = 2) anaplastic ependymomas and one (n = 1) diffuse astrocytoma, anaplastic astrocytoma (n = 1), pilomyxoid astrocytoma (n = 1) and anaplastic pleomorphic xanthoastrocytoma (n = 1). Strong fluorescence was visible in all anaplastic tumors and one PA; one PA demonstrated weak fluorescence. Visible fluorescence was strongly associated with intracellular fluorescence intensity and PPIX concentration (P < 0.05). Within all tumors with visible fluorescence, the intracellular PPIX concentration was greater than 4 µg/ml. Except for moderate and transient elevation of liver enzymes, no 5-ALA related adverse events were reported. CONCLUSION: We demonstrate a strong association between intraoperative observations and spectrometric measurements of PPIX fluorescence in tumor tissue. As in former studies, fluorescence signal was more commonly observed in malignant glial tumors. Further prospective controlled trials should be conducted to investigate the feasibility of 5-ALA-guided resection of pediatric brain tumors.

Intracavitary radioimmunotherapy of high-grade gliomas: present status and future developments.

There is a distinct need for new and second-line therapies to delay or prevent local tumor regrowth after current standard of care therapy. Intracavitary radioimmunotherapy, in combination with radiotherapy, is discussed in the present review as a therapeutic strategy of high potential. We performed a systematic literature search following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). The available body of literature on intracavitary radioimmunotherapy (iRIT) in glioblastoma and anaplastic astrocytomas is presented. Several past and current phase I and II clinical trials, using mostly an anti-tenascin monoclonal antibody labeled with I-131, have shown median overall survival of 19-25 months in glioblastoma, while adverse events remain low. Tenascin, followed by EGFR and variants, or smaller peptides have been used as targets, and most clinical studies were performed with I-131 or Y-90 as radionuclides while only recently Re-188, I-125, and Bi-213 were applied. The pharmacokinetics of iRIT, as well as the challenges encountered with this therapy, is comprehensively discussed. This promising approach deserves further exploration in future studies by incorporating several innovative modifications.

Intraoperative fluorescence diagnosis in the brain: a systematic review and suggestions for future standards on reporting diagnostic accuracy and clinical utility.

BACKGROUND: Surgery for gliomas is often confounded by difficulties in distinguishing tumor from surrounding normal brain. For better discrimination, intraoperative optical imaging methods using fluorescent dyes are currently being explored. Understandably, such methods require the demonstration of a high degree of diagnostic accuracy and clinical benefit. Currently, clinical utility is determined by tissue biopsies which are correlated to optical signals, and quantified using measures such as sensitivity, specificity, positive predictive values, and negative predictive values. In addition, surgical outcomes, such as extent of resection rates and/or survival (progression-free survival (PFS) and overall survival (OS)) have been measured. These assessments, however, potentially involve multiple biases and confounders, which have to be minimized to ensure reproducibility, generalizability and comparability of test results. Test should aim at having a high internal and external validity. The objective of this article is to analyze how diagnostic accuracy and outcomes are utilized in available studies describing intraoperative imaging and furthermore, to derive recommendations for reliable and reproducible evaluations. METHODS: A review of the literature was performed for assessing the use of measures of diagnostic accuracy and outcomes of intraoperative optical imaging methods. From these data, we derive recommendations for designing and reporting future studies. RESULTS: Available literature indicates that potential confounders and biases for reporting the diagnostic accuracy and usefulness of intraoperative optical imaging methods are seldom accounted for. Furthermore, methods for bias reduction are rarely used nor reported. CONCLUSIONS: Detailed, transparent, and uniform reporting on diagnostic accuracy of intraoperative imaging methods is necessary. In the absence of such reporting, studies will not be comparable or reproducible. Future studies should consider some of the recommendations given here.

Establishing risk-adjusted quality indicators in surgery using administrative data-an example from neurosurgery.

BACKGROUND: The current draft of the German Hospital Structure Law requires remuneration to incorporate quality indicators. For neurosurgery, several quality indicators have been discussed, such as 30-day readmission, reoperation, or mortality rates; the rates of infections; or the length of stay. When comparing neurosurgical departments regarding these indicators, very heterogeneous patient spectrums complicate benchmarking due to the lack of risk adjustment. OBJECTIVE: In this study, we performed an analysis of quality indicators and possible risk adjustment, based only on administrative data. METHODS: All adult patients that were treated as inpatients for a brain or spinal tumour at our neurosurgical department between 2013 and 2017 were assessed for the abovementioned quality indicators. DRG-related data such as relative weight, PCCL (patient clinical complexity level), ICD-10 major diagnosis category, secondary diagnoses, age and sex were obtained. The age-adjusted Charlson Comorbidity Index (CCI) was calculated. Logistic regression analyses were performed in order to correlate quality indicators with administrative data. RESULTS: Overall, 2623 cases were enrolled into the study. Most patients were treated for glioma (n = 1055, 40.2%). The CCI did not correlate with the quality indicators, whereas PCCL showed a positive correlation with 30-day readmission and reoperation, SSI and nosocomial infection rates. CONCLUSION: All previously discussed quality indicators are easily derived from administrative data. Administrative data alone might not be sufficient for adequate risk adjustment as they do not reflect the endogenous risk of the patient and are influenced by certain complications during inpatient stay. Appropriate concepts for risk adjustment should be compiled on the basis of prospectively designed registry studies.

Initial psycho-oncological counselling in neuro-oncology: analysis of topics and needs of brain tumour patients.

Diagnosis of a brain tumour is associated with a tremendous disruption of emotional, physical and social well-being. Due to the complexity of the disease and the affection of the central organ, the brain, brain tumour patients differ from other cancer patients. The purpose of this study was to evaluate the concerns and burdens presented by brain tumour patients during their initial psycho-oncological consultation. We performed a retrospective analysis of 53 patients with the diagnosis of either benign or malignant brain tumour, seeking counsel by a neurosurgeon specialised in psycho-oncology. We performed a thematic analysis of the interviews at first consultation identifying themes and patterns and created thematic categories. The main concerns of the patients presented during the first consultations were psychological problems, reported by 40 patients (75.5%). Death and dying was mentioned by more than half of the patients (n = 30, 56.6%). In addition, 62.3% of the patients (n = 33) asked for information regarding the medical treatment and diagnosis. With our study, we created greater awareness of the psychological needs of brain tumour patients in order to define treatment strategies for this important aspect of disease. We showed that there is a need for patients to talk about death even during the initial consultation. Psycho-oncologist in a neuro-oncological setting should be prepared for topics like that and should have a neurosurgical background or collaborate with members of the surgical team in order to provide the patients with medical details and to better understand the impact of the disease.

The Simpson grading in meningioma surgery: does the tumor location influence the prognostic value?

In meningiomas, location-specific differences of the prognostic value of the Simpson classification are sparsely investigated but can influence strategy of surgery. We therefore compared the prognostic value of the Simpson classification in different tumor locations. Progression was compared with Simpson grade in 826 meningioma patients (median age 58 years, female:male ratio 2.4) in location-specific uni- and multivariate analyses. Simpson grade strongly correlated with tumor location (p < .001). Within a median follow-up of 50 months, recurrence was observed in 107 of 803 patients (13%). In general, increasing Simpson grade (p = .002) and subtotal resection (STR, ≥grade III) were correlated with tumor recurrence [hazard ratio (HR): 1.87; p = .004]. In 268 convexity meningiomas, frequency of tumor recurrence correlated with Simpson grade (p = .034). Risk of recurrence was similar after grade I and II resections, tended to increase after grade III (HR: 2.35; p = .087) but was higher after grade IV resections (HR: 7.35; p = .003). Risk of recurrence was higher after STR (HR: 4.21; p = .001) than after gross total resection (GTR, ≤grade II). Contrarily, increasing Simpson grade and STR were not correlated with progression in 102 falx, 38 posterior fossa and nine intraventricular meningiomas. In 325 skull base lesions, risk of recurrence was similar after GTR and STR (p = .198) and was only increased after grade IV resections (HR: 3.26; p = .017). Simpson grading and extent of resection were not equally prognostic in all locations. Lower impact of extent of resection should be considered during surgery for skull base, posterior fossa and falx meningiomas.