Tag: Neuro-oncology

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High-grade glioma: combined use of 5-aminolevulinic acid and intraoperative ultrasound for resection and a predictor algorithm for detection

J Neurosurg 143:323–331, 2025

Combining 5-aminolevulinic acid (5-ALA) fluorescence and intraoperative ultrasound (ioUS) significantly improved the sensitivity and specificity for detecting high-grade glioma during surgery, compared to either technique alone. A machine learning algorithm (HGGPredictor) further enhanced intraoperative tumor margin prediction, suggesting a new standard for safer, more effective resections.

• Combining 5-ALA fluorescence and intraoperative ultrasound (ioUS) improves the accuracy of high-grade glioma (HGG) resection compared to using either method alone.

• 5-ALA shows higher sensitivity (84.9%), while ioUS provides higher specificity (84.5%); combined, they reach sensitivity of 91% and specificity of 86%.

• The combined approach is especially valuable for maximizing tumor removal while minimizing neurological damage, particularly near eloquent brain regions.

• A machine learning algorithm (HGGPredictor) was developed to predict tumor presence during surgery based on 5-ALA and ioUS results.

• The study included 72 patients and 301 biopsies, with histological analysis as the reference standard.

• The benefit of combination is greatest for strong fluorescence or hyperechogenicity; ioUS is particularly helpful when 5-ALA fluorescence is weak.

• The combined method is accessible and can be integrated into existing surgical protocols without major additional costs.

• Limitations include single-center design and lack of a control group, but results suggest a new standard for HGG resection.

 

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To scan or not to scan? A retrospective cohort study analysing the efficacy of routine post‑operative CT after brain biopsy

Acta Neurochirurgica (2024) 166:288

Postoperative management following elective cranial surgery, particularly after biopsy procedures, varies significantly across neurosurgical centres. Routine postoperative head CT scans, traditionally performed to detect complications such as intracranial bleeding or cerebral oedema, lack substantial evidence supporting their necessity.

Methods This study is a retrospective cohort analysis conducted at a regional neurosurgical department of 236 patients who underwent brain biopsies between 2018 and 2022. Patient data, including demographics, surgical details, and postoperative outcomes, were collected and analysed. The outcomes investigated were the incidence and impact of postoperative CT scans on time to discharge, management changes, and the influence of preoperative anticoagulation.

Results Out of 236 patients, 205 (86.86%) underwent postoperative CT scans. There was no significant relationship between postoperative hematoma, as detected on a CT scan, and neurological deficit (p = 0.443), or between preoperative anticoagulation and postoperative bleeding on CT scans (p = 0.464). Patients who had postoperative CT scans had a significantly longer length of stay (LOS) compared to those who did not (p < 0.001). Intraoperative bleeding was a predictor of hematoma on postoperative CT (p = 0.017) but not of postoperative neurological deficit. The routine postoperative CT scan showed limited predictive value for symptomatic deficits, with a positive predictive value of 6.67% and a negative predictive value of 96.88%.

Conclusions Routine postoperative CT scans after brain biopsies do not significantly impact management or improve patient outcomes but are associated with longer hospital stays. CT scans should be reserved for patients showing clinical signs of complications rather than used as a routine procedure after a brain biopsy.

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Navigated intraoperative ultrasound in neuro-oncology: volumetric accuracy and correlation with high-field MRI

J Neurosurg 141:79–88, 2024

The use of intraoperative techniques to detect residual tumors has recently become increasingly important. Intraoperative MRI has long been considered the gold standard; however, it is not widely used because of high equipment costs and long acquisition times. Consequently, real-time intraoperative ultrasound (ioUS), which is much less expensive than MRI, has gained popularity. The aim of the present study was to evaluate the capacity of ioUS to accurately determine the primary tumor volume and detect residual tumors.

METHODS A prospective study of adult patients who underwent surgery for intra-axial brain tumors between November 2017 and October 2020 was performed. Navigated intraoperative ultrasound (nioUS) of the brain was used to guide tumor resection and to detect the presence of residual disease. Both convex (5–8 MHz) and linear array (6–13 MHz) probes were used. Tumor volume and residual disease were measured with nioUS and compared with MR images. A linear regression model based on a machine learning pipeline and a Bland-Altman analysis were used to assess the accuracy of nioUS versus MRI.

RESULTS Eighty patients (35 females and 45 males) were included. The mean age was 58 years (range 25–80 years). A total of 88 lesions were evaluated; there were 64 (73%) gliomas, 19 (21.6%) metastases, and 5 (5.7%) other tumors, mostly located in the frontal (41%) and temporal (27%) lobes. Most of the tumors (75%) were perfectly visible on ioUS (grade 3, Mair grading system), except for those located in the insular lobe (grade 2). The regression model showed a nearly perfect correlation (R 2 = 0.97, p < 0.001) between preoperative tumor volumes from both MRI and nioUS. Ultrasonographic visibility significantly influenced this correlation, which was stronger for highly visible (grade 3) tumors (p = 0.01). For residual tumors, the correlation between postoperative MRI and nioUS was weaker (R 2 = 0.78, p < 0.001) but statistically significant. The Bland-Altman analysis showed minimal bias between the two techniques for pre- and postoperative scenarios, with statistically significant results for the preoperative concordance.

CONCLUSIONS The authors’ findings show that most brain tumors are well delineated by nioUS and almost perfectly correlated with MRI-based measurements both pre- and postoperatively. These data support the hypothesis that nioUS is a reliable intraoperative technique that can be used for real-time monitoring of brain tumor resections and to perform volumetric analysis of residual disease.

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Efficacy and Safety of Carmustine Wafer Implantation After Ventricular Opening in Glioblastomas, Isocitrate Dehydrogenase-Wildtype, in Adults

Neurosurgery 94:1227–1236, 2024

We assessed the impact of ventricular opening on postoperative complications and survival of carmustine wafer implantation during surgery of newly diagnosed supratentorial glioblastomas, isocitrate dehydrogenase (IDH)-wildtype in adults.

METHODS: We performed an observational, retrospective, single-center cohort study at a tertiary surgical neurooncological center between January 2006 and December 2021.

RESULTS: One hundred ninety-four patients who benefited from a first-line surgical resection with carmustine wafer implantation were included. Seventy patients (36.1%) had a ventricular opening. We showed that ventricular opening (1) did not increase overall postoperative complication rates (P = .201); (2) did not worsen the early postoperative Karnofsky Performance Status score (P = .068); (3) did not increase the time interval from surgery to adjuvant oncological treatment (P = .458); (4) did not affect the completion of the standard radiochemotherapy protocol (P = .164); (5) did not affect progression-free survival (P = .059); and (6) did not affect overall survival (P = .142).

CONCLUSION: In this study, ventricular opening during first-line surgical resection did not affect the survival and postoperative complications after use of carmustine wafer implantation in adult patients with a newly diagnosed supratentorial glioblastoma, IDH-wildtype. This warrants a prospective and multicentric study to clearly assess the impact of the ventricular opening after carmustine wafer implantation in glioblastoma, IDH-wildtype.

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Surgical Characteristics of Intracranial Biopsy Using a Frameless Stereotactic Robotic Platform: A Single-Center Experience

Operative Neurosurgery 26:502–510, 2024

Cranial robotics are a burgeoning field of neurosurgery. To date, all cranial robotic systems described have been computerized, arm-based instruments that take up significant space in the operating room. The Medtronic Stealth Autoguide robot has a smaller operating room footprint and offers multiaxial, frame-based surgical targeting. The authors set out to define the surgical characteristics of a novel robotic platform for brain biopsy in a large patient cohort.

METHODS: Patients who underwent stereotactic biopsy using the Stealth Autoguide cranial robotic platform from July 2020 to March 2023 were included in this study. Clinical, surgical, and histological data were collected and analyzed.

RESULTS: Ninety-six consecutive patients (50 female, 46 male) were included. The mean age at biopsy was 53.7 ± 18.0 years. The mean target depth was 68.2 ± 15.3 mm. The biopsy diagnostic tissue acquisition rate was 100%. The mean time from incision to biopsy tissue acquisition was 15.4 ± 9.9 minutes. Target lesions were located throughout the brain: in the frontal

lobe (n = 32, 33.3%), parietal lobe (n = 21, 21.9%), temporal lobe (n = 22, 22.9%), deep brain nuclei/thalamus (n = 13, 13.5%),

cerebellum (n = 7, 7.3%), and brainstem (n = 1, 1.0%). Most cases were gliomas (n = 75, 78.2%). Patients were discharged home on postoperative day 0 or 1 in 62.5% of cases. A total of 7 patients developed postoperative complications (7.2%).

CONCLUSION: This cranial robotic platform can be used for efficient, safe, and accurate cranial biopsies that allow for reliable diagnosis of intracranial pathology in a minimally invasive setting.

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A proposed classification system for presigmoid approaches: a scoping review

J Neurosurg 139:965–971, 2023

The “presigmoid corridor” covers a spectrum of approaches using the petrous temporal bone either as a target in treating intracanalicular lesions or as a route to access the internal auditory canal (IAC), jugular foramen, or brainstem. Complex presigmoid approaches have been continuously developed and refined over the years, leading to great heterogeneity in their definitions and descriptions. Owing to the common use of the presigmoid corridor in lateral skull base surgery, a simple anatomy-based and self-explanatory classification is needed to delineate the operative perspective of the different variants of the presigmoid route. Herein, the authors conducted a scoping review of the literature with the aim of proposing a classification system for presigmoid approaches.

METHODS The PubMed, EMBASE, Scopus, and Web of Science databases were searched from inception to December 9, 2022, following the PRISMA Extension for Scoping Reviews guidelines to include clinical studies reporting the use of “stand-alone” presigmoid approaches. Findings were summarized based on the anatomical corridor, trajectory, and target lesions to classify the different variants of the presigmoid approach.

RESULTS Ninety-nine clinical studies were included for analysis, and the most common target lesions were vestibular schwannomas (60/99, 60.6%) and petroclival meningiomas (12/99, 12.1%). All approaches had a common entry pathway (i.e., mastoidectomy) but were differentiated into two main categories based on their relationship to the labyrinth: translabyrinthine or anterior corridor (80/99, 80.8%) and retrolabyrinthine or posterior corridor (20/99, 20.2%). The anterior corridor comprised 5 variations based on the extent of bone resection: 1) partial translabyrinthine (5/99, 5.1%), 2) transcrusal (2/99, 2.0%), 3) translabyrinthine proper (61/99, 61.6%), 4) transotic (5/99, 5.1%), and 5) transcochlear (17/99, 17.2%). The posterior corridor consisted of 4 variations based on the target area and trajectory in relation to the IAC: 6) retrolabyrinthine inframeatal (6/99, 6.1%), 7) retrolabyrinthine transmeatal (19/99, 19.2%), 8) retrolabyrinthine suprameatal (1/99, 1.0%), and 9) retrolabyrinthine trans-Trautman’s triangle (2/99, 2.0%).

CONCLUSIONS Presigmoid approaches are becoming increasingly complex with the expansion of minimally invasive techniques. Descriptions of these approaches using the existing nomenclature can be imprecise or confusing. Therefore, the authors propose a comprehensive classification based on the operative anatomy that unequivocally describes presigmoid approaches simply, precisely, and efficiently.

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Brain metastasis resection: the impact of fluorescence guidance (MetResect study)

Neurosurg Focus 55(2):E10, 2023

Maximal resection of brain metastases (BMs) improves both progression-free survival and overall survival (OS). Fluorescein sodium (FL) in combination with the YELLOW 560-nm filter is a safe and feasible method for visualizing residual tumor tissue during BM resection. The authors of this study aimed to show that use of FL would positively influence the volumetric extent of resection (EOR) and thus the survival outcome in patients undergoing BM resection.

METHODS Analyzing their institution’s prospective brain tumor registry, the authors identified 539 consecutive patients with BMs (247 women, mean age 62.8 years) by using preoperative high-quality MR images for volumetric analysis. BMs were resected under white light (WL) in 293 patients (54.4%; WL group) and under FL guidance in 246 patients (45.6%; FL group). Sex, age, presurgical Karnofsky Performance Status (KPS), recursive partitioning analysis class, and adjuvant treatment modalities were well balanced between the two groups. Volumetric analysis was performed in a blinded fashion by quantifying pre- and postoperative tumor volume based on gadolinium-enhanced T1-weighted sequences.

RESULTS In the FL group, the postoperative tumor volume was significantly smaller (p = 0.01), and hence the quantitative EOR was significantly larger (p = 0.024) and OS was significantly longer (p = 0.0001) (log-rank testing). Multivariate Cox regression modeling showed that age, presurgical KPS, metastasis status, and FL-guided resection are independent prognostic factors for survival.

CONCLUSIONS Compared with WL resection, FL-guided BM resection increased resection quality, significantly improved EOR, and prolonged OS.

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Aggressive pituitary neuroendocrine tumors: current practices, controversies, and perspectives, on behalf of the EANS skull base section

Acta Neurochirurgica (2021) 163:3131–3142

Aggressive pituitary neuroendocrine tumors (APT) account for 10% of pituitary tumors. Their management is a rapidly evolving field of clinical research and has led pituitary teams to shift toward a neuro-oncological-like approach.

The new terminology “Pituitary neuroendocrine tumors” (PitNet) that was recently proposed to replace “pituitary adenomas” reflects this change of paradigm. In this narrative review, we aim to provide a state of the art of actual knowledge, controversies, and recommendations in the management of APT.

We propose an overview of current prognostic markers, including the recent five-tiered clinicopathological classification. We further establish and discuss the following recommendations from a neurosurgical perspective: (i) surgery and multi-staged surgeries (without or with parasellar resection in symptomatic patients) should be discussed at each stage of the disease, because it may potentialize adjuvant medical therapies; (ii) temozolomide is effective in most patients, although 30% of patients are non-responders and the optimal timeline to initiate and interrupt this treatment remains questionable; (iii) some patients with selected clinicopathological profiles may benefit from an earlier local radiotherapy and/or chemotherapy; (iv) novel therapies such as VEGF-targeted therapies and anti-CTLA-4/anti-PD1 immunotherapies are promising and should be discussed as 2nd or 3rd line of treatment.

Finally, whether neurosurgeons have to operate on “pituitary adenomas” or “PitNets,” their role and expertise remain crucial at each stage of the disease, prompting our community to deal with evolving concepts and therapeutic resources.

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Laser Ablation of Abnormal Neurological Tissue Using Robotic Neuroblate System (LAANTERN)

Neurosurgery 86:538–547, 2020

Stereotactic laser ablation (SLA) has demonstrated potential utility for a spectrum of difficult to treat neurosurgical pathologies in multiple small and/or retrospective single-institutional series. Here, we present the safety profile of SLA of intracranial lesions from the Laser Ablation of Abnormal Neurological Tissue using Robotic NeuroBlate System (LAANTERN; Monteris Medical) multi-institutional, international prospective observational registry.

OBJECTIVE: To determine the procedural safety of SLA for intracranial lesions.

METHODS: Prospective procedural safety and hospitalization data from the first 100 treated LAANTERN patients was collected and analyzed.

RESULTS: Mean age and baseline Karnofsky Performance Status (KPS) were 51(±17) yr and 83(± 15), respectively. In total, 81.2% of patients had undergone prior surgical or radiation treatment. Most patients had a single lesion (79%) ablated through 1 burr hole (1.2±0.7 per patient), immediately following a lesion biopsy. In total, >90% of the lesion was ablated in 72% of treated lesions. Average total procedural time was 188.2 ± 69.6 min, and average blood loss was 17.7 ± 55.6 ccs. The average length of intensive care unit (ICU) and hospital stays before discharge were 38.1 ± 62.7 h and 61.1 ± 87.2 h, respectively. There were 5 adverse events (AEs) attributable to SLA (5/100; 5%). After the procedure, 84.8% of patients were discharged home. There was 1 mortality within 30 d of the procedure (1/100; 1%), which was not attributable to SLA.

CONCLUSION: SLA is a safe, minimally invasive procedure with favorable postprocedural ICU and hospital utilization profiles.

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USim: A New Device and App for Case-Specific, Intraoperative Ultrasound Simulation and Rehearsal in Neurosurgery

Operative Neurosurgery 14:572–578, 2018

Intraoperative ultrasound (iUS) is an excellent aid for neurosurgeons to perform better and safer operations thanks to real time, continuous, and high-quality intraoperative visualization. OBJECTIVE: To develop an innovative training method to teach how to perform iUS in neurosurgery.

METHODS: Patients undergoing surgery for different brain or spine lesions were iUS scanned (before opening the dura) in order to arrange a collection of 3-dimensional, US images; this set of data was matched and paired to preoperatively acquired magnetic resonance images in order to create a library of neurosurgical cases to be studied offline for training and rehearsal purposes. This new iUS training approach was preliminarily tested on 14 European neurosurgery residents, who participated at the 2016 European Association of Neurosurgical Societies Training Course (Sofia, Bulgaria).

RESULTS: USim was developed by Camelot and the Besta NeuroSim Center as a dedicated app that transforms any smartphone into a “virtual US probe,” in order to simulate iUS applied to neurosurgery on a series of anonymized, patient-specific cases of different central nervous system tumors (eg, gliomas, metastases, meningiomas) for education, simulation, and rehearsal purposes. USim proved to be easy to use and allowed residents to quickly learn to handle a US probe and interpret iUS semiotics.

CONCLUSION: USim could help neurosurgeons learn neurosurgical iUS safely. Furthermore, neurosurgeons could simulate many cases, of different brain/spinal cord tumors, that resemble the specific cases they have to operate on. Finally, the library of caseswould be continuously updated, upgraded, and made available to neurosurgeons.

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Hypnosis for Awake Surgery of Low-grade Gliomas

Hypnosis for Awake Surgery of Low-grade Gliomas

Neurosurgery 78:53–61, 2016

Awake craniotomy with intraoperative electric stimulation is a reliable method for extensive removal of low-grade gliomas while preserving the functional integrity of eloquent surrounding brain structures. Although fully awake procedures have been proposed, asleep-awake-asleep remains the standard technique. Anesthetic contraindications are the only limitation of this method, which is therefore not reliable for older patients with high-grade gliomas.

OBJECTIVE: To describe and assess a novel method for awake craniotomy based on hypnosis.

METHODS: We proposed a novel hypnosedation procedure to patients undergoing awake surgery for low-grade gliomas in our institution between May 2011 and April 2015. Surgical data were retrospectively recorded. The subjective experience of hypnosis was assessed by 3 standardized questionnaires: the Cohen Perceived Stress Scale, the Posttraumatic Stress Disorder Checklist Scale, the Peritraumatic Dissociative Experience Questionnaire, and a fourth questionnaire designed specifically for this study.

RESULTS: Twenty-eight questionnaires were retrieved from 43 procedures performed on 37 patients. The Peritraumatic Dissociative Experience Questionnaire revealed a dissociation state in 17 cases. The Perceived Stress Scale was pathological in 8 patients. Two patients in this group stated that they would not accept a second hypnosedation procedure. The Posttraumatic Stress Disorder Checklist Scale revealed 1 case of posttraumatic stress disorder. Burr hole and bone flap procedures were the most frequently reported unpleasant events during opening (15 of 52 events).

CONCLUSION: The main findings of our study are the effectiveness of the technique, which in all cases allowed resection of the tumor up to functional boundaries, and the positive psychological impact of the technique in most of the patients.

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The Impact of Sedation on Brain Mapping

Brain Mapping

Neurosurgery 75:117–123, 2014

During awake craniotomies, patients may either be awake for the entire duration of the surgical intervention (awake-awake-awake craniotomy, AAA) or initially sedated (asleep-awake-asleep craniotomy, SAS).

OBJECTIVE: To examine whether prior sedation in SAS may restrict brain mapping, we conducted neuropsychological tests in patients by means of a standardized anesthetic regimen comparable to an SAS.

METHODS: We prospectively examined patients undergoing surgery either under total intravenous anesthesia (TIVA) or under regional anesthesia with slight sedation (RAS). The tests included the DO40 picture-naming test, the digit span, the Regensburg Word Fluency Test, and the finger-tapping test. Each test was conducted 3 times for every patient in the TIVA and RAS groups, once before surgery and twice within about 35 minutes after the end of sedation. Patients undergoing AAA were examined preoperatively and intraoperatively.

RESULTS: In the AAA group, no significant difference was found between preoperative and intraoperative test results. In the TIVA and RAS groups, postoperative tests showed worse results than preoperative tests. In most tests, patients improved from the first to the second postoperative test.

CONCLUSION: Cognitive and motor performance were significantly influenced by prior sedation in the TIVA and RAS groups, but not in the AAA group. Therefore, prior sedation may be assumed to cause a change in the baselines, which may compromise brain mapping and thus endanger a patient’s neurological outcome in the case of an SAS.

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The preoperative use of navigated transcranial magnetic stimulation facilitates early resection of suspected low-grade gliomas in the motor cortex

The preoperative use of navigated transcranial magnetic stimulation facilitates early resection of suspected low-grade gliomas in the motor cortex

Acta Neurochir (2013) 155:1813–1821

Resection is recommended for low-grade gliomas, but often it is not performed if the tumor is suspected of invading the primary motor cortex. The study aim is to assess what influence preoperative navigated transcranial magnetic stimulation (nTMS) has on the treatment strategy and clinical outcome for suspected low-grade gliomas in presumed motor eloquent location.

Methods This paper reports on all our patients with gliomas in the primary motor cortex that were non-enhancing on MRI, since we began using nTMS (n=11). For the comparison group, we identified the 11 most recent such patients just before we started using nTMS.

Results Exact delineation of motor functional versus nonfunctional cortical tissue was provided by nTMS in all cases, also within the area of altered FLAIR signal. In 6 out of 11 cases, the nTMS mapping result changed the treatment plan towards early and more extensive resection. Only one nTMS patient had another seizure within the follow-up period, whereas four patients in the comparison group had further seizures. In the nTMS group, 1 of 4 patients with pre-op neurological deficits improved by one year; whereas the comparison group had increased neurological deficits in 3 of the 8 patients not having surgery. The median (range) change of tumor volume from baseline to 1 year was −83 % (−67 % to −100 %) in the nTMS group, but +12 % (+40 % to −56 %) in the comparison group (p<0.001).

Conclusions nTMS provides accurate motor mapping results also in infiltrative gliomas and enables more frequent and more extensive surgical resection of non-enhancing gliomas in or near the primary motor cortex. The substantial differences observed here in neurological and oncological outcomes suggest that further comparative research is warranted.

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