Fluorescein Application in Cranial and Spinal Tumors Enhancing at Preoperative MRI and Operated With a Dedicated Filter on the Surgical Microscope: Preliminary Results in 279 Patients Enrolled in the FLUOCERTUM Prospective Study

Sodium fluorescein and 5-aminolevulinic acid fluorescence- guided biopsy in brain lesions: a systematic review and meta-analysis

PURPOSE

Stereotactic brain biopsies are highly efficient for diagnosing intracerebral pathologies, particularly when surgical resection is infeasible. Fluorescence-based agents such as 5-aminolevulinic acid (5-ALA) and fluorescein sodium (NaFl) can enhance diagnostic accuracy and safety, improving the visualization of lesional tissues. This meta-analysis aimed to evaluate their effect on diagnostic yield and complication rates of brain biopsies.

METHODS

This study adhered to Cochrane and PRISMA guidelines. We assessed studies for diagnostic yield and complication rates. Data was analyzed using a random-effects model in RStudio. Diagnostic accuracy measures such as sensitivity and predictive values were calculated based on fluorescence visibility in biopsy samples.

RESULTS

Thirty-two non-randomized studies were included, comprising 947 patients, with a mean age ranging from 37 to 77 years, and a mean sample number ranging from 1 to 15 specimens. Diagnostic yields were high: 93% for NaFl and 96% for 5-ALA. Major complications occurred in 3% of procedures with both agents, while minor complications were reported in 7% and 5% with NaFl and 5-ALA respectively. The Negative-predictive-value (NPV) of 5-ALA and NaFl were 8-11% and 60-80% respectively. NaFl demonstrates higher sensitivity and specificity at 84% and 100% compared to 5-ALA's 66%. and 85% respectively.

CONCLUSION

5-ALA and NaFl provide high diagnostic yields with acceptable safety profiles in stereotactic biopsies. NaFl showed higher sensitivity and specificity. NaFl outperforms 5ALA in terms of NPV making it more efficient for small lesions near eloquent regions or major blood vessels. The significance of these findings can be further ascertained through randomized trials.

Efficacy, safety, and impact of fluorescein in frameless stereotactic needle biopsies - a case series

Stereotactic needle biopsy stands as a crucial method for diagnosing intracranial lesions unsuitable for surgical intervention. Nonetheless, the potential for sampling errors lead to innovative approaches to enhance diagnostic precision. This study contrasts the outcomes of patients undergoing fluorescein-assisted frameless stereotactic needle biopsy with those receiving traditional biopsies to evaluate the impact on diagnostic accuracy and safety. This study included patients with contrast-enhancing intracranial lesions, comprising a prospective group undergoing fluorescein-assisted biopsies and a retrospective group undergoing conventional biopsies at the same institution. We've collected data on demographics, procedural specifics, diagnostic outcomes, and postoperative events. A comparative analysis involved 43 patients who received fluorescein-assisted biopsies against 77 patients who underwent conventional biopsies. The average age was 60.5 years. The fluorescein group exhibited a 93% success rate in diagnosis, markedly higher than the 70.1% in the non-fluorescein group (OR = 5.67; 95%IC: 1.59-20.24; p < 0.01). The rate of complications was statistically similar across both cohorts. Despite its established value, stereotactic needle biopsy is susceptible to inaccuracies and complications. The application of fluorescence-based adjuncts like 5-ALA and fluorescein has been investigated to improve diagnostic fidelity and reduce risks. These technologies potentially minimize the necessity for multiple biopsies, decrease surgical duration, and provide immediate verification of tumor presence. Fluorescein-assisted stereotactic biopsy emerges as an effective, secure alternative to conventional methods.

Comparative efficacy and safety of sodium fluorescein-guided surgery versus standard white light for resection of brain metastases: a systematic review and meta-analysis

PURPOSE

Recent studies have investigated if the sodium fluorescein-guided (SFg) improves the extent of resection of BMs when compared to standard white light (sWL). Therefore, we aimed to assess the comparative efficacy and safety of SFg and sWL for resection of BMs.

METHODS

We searched Medline, Embase, and Cochrane Library databases following Cochrane and PRISMA guidelines for studies reporting comparative data of SFg and WL resection of BMs. We pooled odds ratios (OR) with 95% confidence intervals under random effects and applied I² statistics and leave-one-out sensitivity analysis to assess heterogeneity. I² > 40% was considered significant for heterogeneity.

RESULTS

Five studies involving 816 patients were included, of whom 390 underwent BMs resection with SFg and 426 with sWL, and ages ranging between 26 and 86.2 years old. Analysis revealed a statistically significant higher likelihood of complete resection in the SFg group when compared to the sWL group (OR = 2.15, 95%CI: 1.18-3.92, p = 0.01; I² = 47%). Sensitivity analysis revealed a consistent result in all five scenarios, with low heterogeneity in two of the five scenarios. Three studies reported significant improvement in OS in the SFg group, and the qualitative assessment of complications and procedure-related mortality did not provide sufficient information for conclusions.

CONCLUSION

This systematic review and meta-analysis identified a higher likelihood of complete resection in the SFg group when compared to the standard sWL group. This study is the first to directly compare the impact of SFg and sWL on resection outcomes for BMs.

A prospective study on the usefulness of high-resolution intraoperative infrared thermography in intracranial tumors

Introduction

Infrared thermography (IT) is a non-invasive real-time imaging technique with potential application in different areas of neurosurgery. Despite technological advances in the field, intraoperative IT (IIT) has been an underestimated tool with scarce reports on its usefulness during intracranial tumor resection. We aimed to evaluate the usefulness of high-resolution IIT with static and dynamic thermographic maps for transdural lesion localization, and diagnosis, to assess the extent of resection, and the occurrence of perioperative acute ischemia.

Methods

In a prospective study, 15 patients affected by intracranial tumors (six gliomas, four meningiomas, and five brain metastases) were examined with a high-resolution thermographic camera after craniotomy, after dural opening, and at the end of tumor resection.

Results

Tumors were transdurally located with 93.3% sensitivity and 100% specificity (p < 0.00001), as well as cortical arteries and veins. Gliomas were consistently hypothermic, while metastases and meningiomas exhibited highly variable thermographic maps on static (p = 0.055) and dynamic (p = 0.015) imaging. Residual tumors revealed non-specific static but characteristic dynamic thermographic maps. Ischemic injuries were significantly hypothermic (p < 0.001).

Conclusions

High-resolution IIT is a non-invasive alternative intraoperative imaging method for lesion localization, diagnosis, assessing the extent of tumor resection, and identifying acute ischemia changes with static and dynamic thermographic maps.

Fluorescein-guided surgery in high-grade gliomas: focusing on the eloquent and deep-seated areas

PURPOSE

The vital function of eloquent and deep brain areas necessitates precise treatment for tumors located in these regions. Fluorescein-guided surgery (FGS) has been widely used for high-grade gliomas (HGGs) resection. Nevertheless, the safety and efficacy of utilizing this technique for resecting brain tumors located in eloquent and deep-seated areas remain uncertain. This study aims to assess the safety and extent of resection of HGGs in these challenging tumors with fluorescein and explore its impact on patient survival.

METHODS

A retrospective analysis was conducted on the clinical and radiological data of 67 consecutive patients with eloquent or deep-seated HGGs who underwent surgery between January 2020 and June 2023. Lacroix functional location grade was used to determine the eloquence of the tumors. The comparison between the fluorescence-guided surgery group (FGS, n = 32) and the conventional white-light microscopic surgery group (non-FGS, n = 35) included assessments of extent of resection (EOR), rates of gross total resection (GTR, 100%) and near-total resection (NTR, 99 to 98%), postoperative Neurologic Assessment in Neuro-Oncology (NANO) scores, overall survival (OS), and progression-free survival (PFS), to evaluate the safety and efficacy of fluorescein-guided technology in tumor resection at these specific locations.

RESULTS

Baseline of demographics, lesion location, and pathology showed no significant difference between the two groups. GTR of the FGS group was higher than the non-FGS group (84.4% vs. 60.0%, OR 3.60, 95% CI 1.18-10.28, p < 0.05). The FGS group also showed higher GTR + NTR (EOR ≥ 98%) than the non-FGS group (93.8% vs. 65.7%, OR 7.83, 95% CI 1.86-36.85, p < 0.01). 87.0% of eloquent tumors (Lacroix grade III) in the FGS group achieved GTR + NTR, compared to 52.2% of control group (OR 6.11, 95% CI 1.50-22.78, p < 0.05). For deep-seated tumors, the rate of GTR + NTR in the two groups were 91.7% and 53.3%, respectively (OR 9.62, 95% CI 1.05-116.50, p < 0.05). No significant difference of the preoperative NANO score of the two groups was found. The postoperative NANO score of the FGS group was significantly lower than the non-FGS group (2.56 ± 1.29 vs. 3.43 ± 1.63, p < 0.05). Median OS of the FGS group was 4.2 months longer than the non-FGS group despite no statistical difference (18.2 months vs. 14.0 months, HR 0.63, 95% CI 0.36-1.11, p = 0.112), while PSF was found significantly longer in FGS patients than those of the non-FGS group (11.2 months vs. 7.7 months, HR 0.59, 95% CI 0.35-0.99, p < 0.05).

CONCLUSION

Sodium fluorescein-guided surgery for high-grade gliomas in eloquent and deep-seated brain regions enables more extensive resection while preserving neurologic function and improve patient survival.

Next-generation agents for fluorescence-guided glioblastoma surgery

Glioblastoma is a fast-growing and aggressive form of brain cancer. Even with maximal treatment, patients show a low median survival and are often subjected to a high recurrence incidence. The currently available treatments require multimodal management, including maximal safe surgical resection, followed by radiation and chemotherapy. Because of the infiltrative glioblastoma nature, intraoperative differentiation of cancer tissue from normal brain parenchyma is very challenging, and this accounts for the low rate of complete tumor resection. For these reasons, clinicians have increasingly used various intraoperative adjuncts to improve surgical results, such as fluorescent agents. However, most of the existing fluorophores show several limitations such as poor selectivity, photostability, photosensitization and high costs. This could limit their application to successfully improve glioblastoma resection. In the present perspective, we highlight the possibility to develop next-generation fluorescent tools able to more selectively label cancer cells during surgical resection.

A light in the darkness: sodium fluorescein-assisted peripheral nerve sheath tumors resection - a comprehensive systematic review and single-arm meta-analysis

The treatment for peripheral nerve sheath tumors (PNSTs) is based on surgical excision and the primary goal is to improve symptoms whilst preserving neurological function. In order to improve this technique, surgeons may use sodium fluorescein (SF) to help visualize the neoplasm and, consequently, facilitate its removal. Aiming to assess the efficacy of this emerging surgical strategy, we conducted a systematic review and single-arm meta-analysis. We conducted a systematic search on the PubMed, Embase, and Web of Science databases, following the PRISMA guidelines. Studies without outcomes of interest, case series with less than four patients, letters, comments, technical notes, editorials, reviews, and basic research papers were excluded. The outcomes considered for this study were: the number of tumors that achieved total resection, subtotal resection, or near total resection, the approach/technique utilized by the surgeon, SF-related complications, and total complications. Five studies, with a total of 175 individuals, were included in our survey. Notably, 70% of the neoplasms presented by the patients were schwannomas. Considering extracranial lesions, we found a proportion of 96% (95% CI: 88 - 100%) in total resection, 0% (95% CI: 0-1%) in near total resection, and 4% (95% CI: 0-12%) in subtotal resection, all linked to an amount of 185 analyzed PNSTs. Furthermore, a proportion of 1% (95% CI: 0 - 2%) in SF-related complications was spotted among 183 patients. Finally, total complications analysis accounted for 11% (95% CI: 0 - 25%) among 183 individuals. We concluded that SF-assisted resection of PNSTs is a suitable and relatively safe technique, linked to minimum complications, of which the majority was not associated with the chemical compound itself. Future research is necessary to increase the number of patients available in the current literature and, therefore, enhance future analyses.

The Application of Sodium Fluorescein in Resection of Medulloblastoma Under YELLOW 560 Filter: Feasibility and Preliminary Results of a Monocentric Cohort and Systematic Review

BACKGROUND

Maximizing surgical resection of medulloblastoma (MB) affects overall survival; nevertheless, surgical resection remains a because of the infiltrative behavior of this tumor. Several dyes have been tested for improving tumor visualization; however, few reports with different protocols of fluorophores use are available and the results are inconsistent. Hence, we report our experience with sodium fluorescein in MB surgery, aiming to assess the role of this technique on the extent of resection. Furthermore, we performed a literature review of this topic.

METHODS

Fluorescence characteristics, extent of resection, and clinical outcome were analyzed in 9 consecutively operated patients with MB. A comprehensive literature search and review for English-language articles concerning fluorescein application in MB was conducted.

RESULTS

In our cohort, no side effect related to fluorescein occurred; all tumors presented with an intense or moderate yellow-green enhancement, and fluorescein was judged fundamental in distinguishing tumors from viable tissue in 7 of 9 cases. Gross total resection or near-total resection (i.e., a residual tumor volume <1.5 cm3) was achieved in 8 patients. The review explored the different techniques and surgical interpretations as well as surgical radicality; we did not find a homogenous protocol for fluorescein injection in the published articles. Fluorescence appeared moderate or intense in almost all cases, with a high percentage of usefulness and consensual achievement of a high rate of gross total resection.

CONCLUSIONS

Based on these results, we can infer that fluorescein-guided surgical resection is a safe and valuable method for patients with MB.

Unraveling the mystery of solvation-dependent fluorescence of fluorescein dianion using computational study

Fluorescein, one of the brightest fluorescent dye molecules, is a widely used fluorophore for various applications from biomedicine to industry. The dianionic form of fluorescein is responsible for its high fluorescence quantum yield. Interestingly, the molecule was found to be nonfluorescent in the gas phase. This characteristic is attributed to the photodetachment process, which out-competes the fluorescence emission in the gas phase. In this work, we show that the calculated vertical and adiabatic detachment energies of fluorescein dianion in the gas and solvent phases account for the drastic differences observed in their fluorescence characteristics. The functional dependence of these detachment energies on the dianion's microsolvation was systematically investigated. The performance of different solvent models was also assessed. The higher thermodynamic stability of fluorescein dianion over the monoanion doublet in the solvent phase plays a crucial role in quenching photodetachment and activating the radiative channel with a high fluorescence quantum yield.

Advancements in Glioma Care: Focus on Emerging Neurosurgical Techniques

BACKGROUND

Despite significant advances in understanding the molecular pathways of glioma, translating this knowledge into effective long-term solutions remains a challenge. Indeed, gliomas pose a significant challenge to neurosurgical oncology because of their diverse histopathological features, genetic heterogeneity, and clinical manifestations. Relevant sections: This study focuses on glioma complexity by reviewing recent advances in their management, also considering new classification systems and emerging neurosurgical techniques. To bridge the gap between new neurosurgical approaches and standards of care, the importance of molecular diagnosis and the use of techniques such as laser interstitial thermal therapy (LITT) and focused ultrasound (FUS) are emphasized, exploring how the integration of molecular knowledge with emerging neurosurgical approaches can personalize and improve the treatment of gliomas.

CONCLUSIONS

The choice between LITT and FUS should be tailored to each case, considering factors such as tumor characteristics and patient health. LITT is favored for larger, complex tumors, while FUS is standard for smaller, deep-seated ones. Both techniques are equally effective for small and superficial tumors. Our study provides clear guidance for treating pediatric low-grade gliomas and highlights the crucial roles of LITT and FUS in managing high-grade gliomas in adults. This research sets the stage for improved patient care and future developments in the field of neurosurgery.

Fluorescein-guided resection of a left frontal pre-rolandic cerebral metastasis: how I do it

BACKGROUND

Cerebral metastases (CM) are the most common intracranial tumors; several studies have underlined the fundamental role of neurosurgical lesion removal.

METHOD

We describe the surgical resection of a left frontal single metastasis. We attempted to achieve a radical resection under the intraoperative guidance of fluorescein, with the aid of intraoperative neurological monitoring. This technique can be applied to each contrast enhancing, intra-axial, infiltrative lesion.

CONCLUSION

Fluorescein-guided surgery is a valuable tool in CM surgery to increase the rate of resection; further prospective evaluation of the role of fluorescein in this field is in planning, aiming to study the prognostic impact.

5-aminolevulinic acid, fluorescein sodium, and indocyanine green for glioma margin detection: analysis of operating wide-field and confocal microscopy in glioma models of various grades

Introduction

Surgical resection remains the first-line treatment for gliomas. Several fluorescent dyes are currently in use to augment intraoperative tumor visualization, but information on their comparative effectiveness is lacking. We performed systematic assessment of fluorescein sodium (FNa), 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX), and indocyanine green (ICG) fluorescence in various glioma models using advanced fluorescence imaging techniques.

Methods

Four glioma models were used: GL261 (high-grade model), GB3 (low-grade model), and an in utero electroporation model with and without red fluorescence protein (IUE +RFP and IUE -RFP, respectively) (intermediate-to-low-grade model). Animals underwent 5-ALA, FNa, and ICG injections and craniectomy. Brain tissue samples underwent fluorescent imaging using a wide-field operative microscope and a benchtop confocal microscope and were submitted for histologic analysis.

Results

Our systematic analysis showed that wide-field imaging of highly malignant gliomas is equally efficient with 5-ALA, FNa, and ICG, although FNa is associated with more false-positive staining of the normal brain. In low-grade gliomas, wide-field imaging cannot detect ICG staining, can detect FNa in only 50% of specimens, and is not sensitive enough for PpIX detection. With confocal imaging of low-intermediate grade glioma models, PpIX outperformed FNa.

Discussion

Overall, compared to wide-field imaging, confocal microscopy significantly improved diagnostic accuracy and was better at detecting low concentrations of PpIX and FNa, resulting in improved tumor delineation. Neither PpIX, FNa, nor ICG delineated all tumor boundaries in studied tumor models, which emphasizes the need for novel visualization technologies and molecular probes to guide glioma resection. Simultaneous administration of 5-ALA and FNa with use of cellular-resolution imaging modalities may provide additional information for margin detection and may facilitate maximal glioma resection.

Intraoperative Fluorescein Sodium in Pediatric Neurosurgery: A Preliminary Case Series from a Singapore Children's Hospital

(1) Background: Fluorescein sodium (Na-Fl) has been described as a safe and useful neurosurgical adjunct in adult neurooncology. However, its use has yet to be fully established in children. We designed a study to investigate the use of intraoperative Na-Fl in pediatric brain tumor surgery. (2) Methods: This is a single-institution study for pediatric brain tumor patients managed by the Neurosurgical Service, KK Women's and Children's Hospital. Inclusion criteria consists of patients undergoing surgery for suspected brain tumors from 3 to 19 years old. A predefined intravenous dose of 2 mg/kg of 10% Na-Fl is administered per patient. Following craniotomy, surgery is performed under alternating white light and YELLOW-560 nm filter illumination. (3) Results: A total of 21 patients with suspected brain tumours were included. Median age was 12.1 years old. For three patients (14.3%), there was no significant Na-Fl fluorescence detected and their final histologies reported a cavernoma and two radiation-induced high grade gliomas. The remaining patients (85.7%) had adequate intraoperative fluorescence for their lesions. No adverse side effects were encountered with the use of Na-Fl. (4) Conclusions: Preliminary findings demonstrate the safe and efficacious use of intraoperative Na-Fl for brain tumors as a neurosurgical adjunct in our pediatric patients.

Sodium Fluorescein-Guided Surgery for Resection of Brain Metastases from Lung Cancer: A Consecutive Case Series Study and Literature Review

(1) Introduction and objective: Surgical resection plays an important role in the multidisciplinary treatment of lung cancer patients with brain metastases (BMs). Precisely distinguishing the tumor border intraoperatively to improve and maximize the extent of resection (EOR) without causing permanent neurological defects is crucial but still challenging. Therefore, we introduced our experience of utilizing sodium fluorescein (SF) in microneurosurgery of BMs from lung cancer. This study aims to evaluate whether the use of SF-guided surgery has a positive impact on postoperative outcomes. (2) Materials and methods: A retrospective study was performed to collect data on a consecutive case series of patients with BMs from lung cancer who underwent surgical resection from January 2020 to December 2021 at the Department of Neuro-Oncology, Chongqing University Cancer Hospital. A total of 52 patients were enrolled, of which 23 received SF-guided surgery and 29 did not. EOR was assessed pre- and postoperatively on T1 contrast-enhanced MRI. Clinical and epidemiological data as well as follow-up were gathered and analyzed. (3) Results: Compared with the non-SF-guided group, the SF-guided group revealed a significantly better EOR (87.0% vs. 62.1%) and a lower incidence of local recurrence (8.7% vs. 34.5%). Survival benefits were seen in patients with NSCLC, patients who were undergoing SF-guided surgery, and patients receiving postoperative systemic therapy. (4) Conclusions: SF-guiding under the YELLOW 560 nm filter is a safe and feasible tool for improving the EOR in patients with BMs from lung cancer, leading to better local recurrence control and prolonged survival.

Assessing the role of sodium fluorescein in peripheral nerve sheath tumors and mimicking lesions surgery: An update after 142 cases

Objective

Peripheral nerve sheath tumors (PNST) include mainly schwannomas and neurofibromas. Surgical resection represents the mainstay of treatment but due to their pathogenesis, distinguishing between intact functional nerve and the fibers from whence the PNST arose may not always be easy to perform, constituting the most relevant risk factor in determining a worsening in neurological condition. The introduction of intraoperative tools to better visualize these tumors could help achieve a gross-total resection. In this study, we analyzed the effect of sodium fluorescein (SF) on the visualization and resection of a large cohort of PNST.

Methods

Between September 2018 and December 2021, 142 consecutive patients harboring a suspected PNST underwent fluorescein-guided surgery at the Department of Neurosurgery of the Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy. All patients presented with a different degree of contrast enhancement at preoperative MRI. SF was intravenously injected after intubation at 1 mg/kg. Intraoperative fluorescein characteristics and postoperative neurological and radiological outcomes were collected, analyzed, and retrospectively compared with a historical series.

Results

142 patients were included (42 syndromic and 100 sporadic); schwannoma was the predominant histology, followed by neurofibroma (17 neurofibroma e 12 plexiform neurofibroma) and MPNST. Bright fluorescence was present in all cases of schwannomas and neurofibromas, although with a less homogeneous pattern, whereas it was significantly less evident for malignant PNST; perineurioma and hybrid nerve sheath tumors were characterized by a faint fluorescence enhancement. The surgical resection rate in the general population and even among the subgroups was about 66.7%; from the comparative analysis, we found a consistently higher rate of complete tumor removal in plexiform neurofibromas, 66% in the "fluorescent" group vs 44% in the "historical" group (p-value < 0.05). The rate of complications and mean surgical time were superimposable among the two populations.

Conclusions

SF is a valuable method for safe fluorescence-guided PNST and mimicking lesions resection. Our data showed a positive effect of fluorescein-guided surgery in increasing the rate of surgical resection of plexiform neurofibromas, suggesting a possible role in improving the functional and oncological outcome of these lesions.

Hemangioblastomas and Other Vascular Origating Tumors of Brain or Spinal Cord

Hemangioblastomas (HBs) are highly vascularized, slow-growing, rare benign tumors (WHO grade I). They account for about 2% of intracranial neoplasms; however, they are the most common primary cerebellar tumors in adults. Another frequent seat is the spinal cord (2-10% of primary spinal cord tumors). HBs are constituted by stromal and capillary vascular cells; macroscopically, HBs appear as nodular tumors, with or without cystic components. Although most of the HBs are sporadic (57-75%), they represent a particular component of von Hippel-Lindau disease (VHL), an autosomal dominant syndrome with high penetrance, due to a germline pathogenic mutation in the VHL gene, which is a tumor suppressor with chromosomal location on the short arm of chromosome three. VHL disease determines a variety of malignant and benign tumors, most frequently HBs, renal cell carcinomas, pheochromocytomas/paragangliomas, pancreatic neuroendocrine tumors, and endolymphatic sac tumors. Up to 20% of cases are due to de novo pathogenic variants without a family history. Many epidemiologic details of these tumors, especially the sporadic forms, are not well known. The median age of patients with sporadic HBS is about 40 years. More than two-third of VHL patients develop one or more central nervous system HBs during their lifetime; in case of VHL, patients at first diagnosis are usually younger than the patients with sporadic tumors. The most common presenting signs and symptoms are related to increased intracranial pressure, cerebellar signs, or spinal cord alterations in case of spinal involvement. Magnetic resonance imaging is the gold standard for the diagnosis, assessment, and follow-up of HBs, both sporadic and syndrome-related; angiography is rarely performed because the diagnosis is easily obtained with magnetic resonance. However, the diagnosis of an asymptomatic lesion does not automatically result in therapeutic actions, as the risks of treatment and the onset of possible neurological deficit need to be balanced, considering that HBs may remain asymptomatic and have a static or slow-growing behavior. In such cases, regular follow-up can represent a valid therapeutic option until the patients remain asymptomatic. There are no actual pharmacological therapies that are demonstrated to be effective for HBs. Surgery represents the primary therapeutic approach for these tumors. Observation or radiotherapy also plays a role in the long-term management of patients harboring HBs, especially in VHL; in few selected cases, endovascular treatment has been suggested before surgical removal. This chapter presents a systematic overview of epidemiology, clinical appearance, histopathological and neuroradiological characteristics of central nervous system HBs. Moreover, the genetic and molecular biology of sporadic and VHL HBS deserves special attention. Furthermore, we will describe all the available therapeutic options, along with the follow-up management. Finally, we will briefly report other vascular originating tumors as hemangioendotheliomas, hemangiomas, or angiosarcomas.

Towards an Established Intraoperative Oncological Favorable Tool: Results of Fluorescein-Guided Resection from a Monocentric, Prospective Series of 93 Primary Glioblastoma Patients

It is commonly reported that maximizing surgical resection of contrast-enhancing regions in patients with glioblastoma improves overall survival. Efforts to achieve an improved rate of resection have included several tools: among those, the recent widespread of fluorophores. Sodium fluorescein is an unspecific, vascular dye which tends to accumulate in areas with an altered blood-brain barrier. In this retrospective analysis of patients prospectively enrolled in the FLUOCERTUM study, we aimed to assess the role of fluorescein-guided surgery on surgical radicality, survival, and morbidity. A retrospective review based on 93 consecutively and prospectively enrolled IDH wild-type glioblastoma patients (2016-2022) was performed; fluorescence characteristics, rate of resection, clinical outcome, and survival were analyzed. No side effect related to fluorescein occurred; all of the tumors presented a strong yellow-green enhancement and fluorescein was judged fundamental in distinguishing tumors from viable tissue in all cases. Gross total resection was achieved in 77 cases out of 93 patients (82.8%). After a mean follow-up time of 17.4 months (3-78 months), the median progression-free survival was 12 months, with a PFS-6 and PFS-12 of 94.2% and 50%, respectively, whereas median overall survival was estimated to be 16 months; survival at 6, 12, and 24 months was 91.8%, 72.3%, and 30.1%, respectively. Based on these results, we can assert that the fluorescein-guided technique is a safe and valuable method for patients harboring a newly diagnosed, untreated glioblastoma.

Diagnostic and surgical management of primary central nervous system angioleiomyoma: A case report and literature review

Angioleiomyoma (ALM) is a benign smooth muscle neoplasm that mainly occurs in lower extremities subcutaneous tissue and generally affects middle-aged adults. This tumor histotype may rarely localize intracranially, although only a few cases have been described in the literature. We report a case of intracranial ALM, whose differential diagnosis has been particularly challenging, and firstly provide a comprehensive radiological and intra-operative evaluation of a such rare entity. This represents also the first report of the use of intraoperative confocal microscopy in ALM and the first documented short-term recurrence. At this regard, a scoping literature review has been conducted with the aim of presenting the major clinical and diagnostic features along with the proposed therapeutic strategies.

The role of sodium fluorescein in pediatric supratentorial intra-axial tumor resection: new insights from a monocentric series of 33 consecutive patients

INTRODUCTION

Surgical resection represents the mainstay of treatment, in pediatric central nervous system (CNS) tumors, and aggressive resection correlates with prognosis for several histotypes. Sodium fluorescein (SF), a green, water-soluble dye, is used as neurosurgical fluorescent tracer thanks to its property to accumulate in cerebral regions of blood-brain barrier disruption, acting as a valid tool to improve the extent of resection in tumors enhancing at preoperative MRI. Brain neoplasms represent a heterogeneous group of tumors in the pediatric age, constituting the most common solid cancers; they typically show a varying degree of contrast enhancement on MRI.

MATERIALS AND METHODS

In March 2016, the authors started a prospective, observational trial to evaluate intraoperative fluorescence's characteristics of CNS tumors, the percentage of extent of resection, thanks to fluorescein aid, and side effects related to fluorescein administration. This report is based on a retrospective analysis of a group of 33 consecutive pediatric patients harboring a supratentorial lesion.

RESULTS

In 17 of 33 (51.5%) procedures, fluorescence was reported as intense; in 14 of 33 (42.4%), moderate; and in 2 of 33 (6.1%), slight. Intraoperative fluorescence corresponds to preoperative-MRI-documented contrast enhancement. In 28 of 33 (84.8%) surgical procedures, SF was considered useful; in 2 of 33 (6.1%), partial useful; and in 3 of 33 (9.1%), not essential because the tumor was already recognizable. No adverse effect to SF administration was registered.

CONCLUSION

Fluorescein-guided surgery with a dedicated filter on the microscope is a safe and effective technique to improve visualization and resection of different pediatric brain tumors.

Sodium fluorescein in pediatric neurosurgery: a systematic review with technical considerations and future perspectives

BACKGROUND

Sodium fluorescein (SF) is routinely used in several centers as a valid intraoperative adjunct in adult oncological neurosurgery. Its use in pediatric neurosurgery is increasing, although its role is not yet well-defined in children. We reviewed the current literature in order to evaluate the use of SF in children with CNS and PNS lesions.

METHODS

For this systematic review, we searched PubMed, Scopus, and Embase databases, and forward and backward citations for studies published between database inception and July 31st, 2022. We included any article type or congress abstract adding at least a new case, without restrictions of language or publication status, concerning the use of SF in neurosurgical procedures in patients under 18 years of age. We excluded studies concerning purely vascular cases and cerebrospinal fluid leaks.

RESULTS

Of 4094 records identified, 19 articles were eligible and included for further analysis. As per July 31st, 2022, at least 119 patients aged from 11 months to 17.9 years underwent surgery with SF. No serious adverse events were reported. A large variety of tumor types was operated, in most cases resected under the specific YELLOW 560 nm filter after a low-dose SF injection (2-5 mg/kg) at the end of anesthesia induction. SF was reported particularly useful in gangliogliomas and pilocytic astrocytomas.

DISCUSSION/CONCLUSION

Given its easy-to-use profile, low cost, and safety, SF seems to be a feasible and valid adjunct in the pediatric population when aiming at individuating a biopsy target or maximizing extent of resection, particularly in some tumor types. Further studies are required to strengthen the evidence on its impact on outcomes.

Sodium fluorescein in pediatric oncological neurosurgery: a pilot study on 50 children

BACKGROUND

Sodium fluorescein (SF) is currently considered a valid intraoperative adjunct in the resection of high-grade brain lesions in adults. Experiences in pediatric groups and in low-grade gliomas and other low-grade lesions are still limited in literature, and subjective evaluation of fluorescence is still a limitation.

MATERIAL AND METHODS

This study retrospectively reviewed all patients with brain or spine lesions operated on from September 2021 to July 2022 in the Pediatric Neurosurgery Unit of Hôpital Femme Mère Enfant, Lyon, who had received 5 mg/kg of 10%. Surgery was performed using a YELLOW560 filter at crucial times. At the end of surgery, the first operator completed a questionnaire, including his opinion on whether SF had been useful in tumor resection, recorded as a binary variable. Post hoc, surgical images were reviewed using ImageJ, an open-source Java image processing platform. In order to compare independent discrete variables, we applied the Student's t test, and we applied the Chi-square or Fisher exact test for binary variables. A threshold of p < 0.05 was set for statistical significance.

RESULTS

We included 50 pediatric patients (0.2-17.6 years old). Forty/50 lesions showed SF uptake (80%). The differentiation between healthy and affected tissue, thanks to SF, subjectively evaluated by the surgeon, had as objective counterpart the statistically significant higher brightness of green in lesions, registered by the software (p < 0.001). SF overall allowed a good differentiation in 33/50 lesions, and overall utility of SF has been noted in 67% of them. When specifically considering gliomas, overall utility reached 75%.

CONCLUSION

SF is a feasible, safe, and useful intraoperative adjunct in pediatric neurosurgery. In particular, it seems to have a promising role in some low-grade infiltrating glial tumors. The subjective evaluation of fluorescence seems to be reliable with respect to image analyses software.

Pediatric Low-Grade Glioma Surgery with Sodium Fluorescein: Efficient Localization for Removal and Association with Intraoperative Pathological Sampling

Low-grade gliomas are among the most common CNS lesions in pediatrics and surgery is often the first-line treatment. Intraoperative tools have been developed to maximize the results of surgery, and in particular dyes such as sodium fluorescein (SF) have been investigated in high-grade adult lesions. The use of SF in pediatric low-grade gliomas is still unclear. We retrospectively reviewed 22 pediatric CNS low-grade gliomas operated on with SF from September 2021 to October 2022. A total of 86% of lesions showed SF uptake, which was helpful intraoperatively (confirmation of initial localization of the tumor, or identification of tumor remnants) in 74% of them. The intraoperative fluorescence seems associated with gadolinium enhancement at the preoperative MRI. Interestingly, the extemporaneous pathological sampling (EPS) was informative in every case showing SF uptake, whereas in cases without SF uptake, the EPS was non-informative, although the tissue was later confirmed as pathological. These findings highlight the interest of SF for perioperative diagnosis of tumor tissue and may suggest in which cases the differentiation of tumor-healthy tissue could be especially blurred, posing difficulties for the pathologist.

Fluorescein sodium in the surgical treatment of pleomorphic xanthoastrocytomas: Results from a retrospective study

OBJECTIVE

Pleomorphic xanthoastrocytoma (PXA) is a rare brain tumor, most commonly affecting children and young adults. Surgical resection represents the mainstay of treatment, and extent of resection is associated with improved survival. In this study, we analyzed the role of sodium fluorescein (SF) in improving intraoperative visualization easing resection.

METHODS

Surgical database of FLUOCERTUM study (Besta Institute, Milan, Italy) was retrospectively reviewed to find pleomorphic xanthoastrocytomas and anaplastic xanthoastrocytomas, according to WHO-2016/2021 classification, surgically removed by a fluorescein-guided technique from March 2016 to February 2022. SF was intravenously injected (5mg/kg) immediately after induction of general anesthesia. Tumors were removed using a microsurgical technique with the YELLOW 560 filter (Carl Zeiss Meditec, Oberkochen, Germany).

RESULTS

Twelve patients (7 males and 5 females; 3 pediatric patients, mean age 10 years, range 5 to 13 years and 9 adult patients, mean age 50.6 years, range 35 to 63 years) underwent fluorescein-guided surgery. No side effects related to SF occurred. In all tumors, contrast enhancement on preoperative MRI correlated with intense, heterogeneous yellow fluorescence with bright fluorescent cystic fluid. Fluorescein was considered helpful in distinguishing tumors from viable tissue in all cases. Gross total resection was achieved in 8 cases (66.7%); in 4 cases, otherwise, the resection was subtotal with fluorescent residual spots to avoid neurological worsening (33.3%).

CONCLUSIONS

The use of SF is a valuable method for safe fluorescence-guided tumor resection. Our data documented a positive effect of fluorescein-guided surgery on intraoperative visualization, suggesting a probable role in improving the extent of resection during yellow surgery of PXA.

Sporadic and von Hippel-Lindau Related Hemangioblastomas of Brain and Spinal Cord: Multimodal Imaging for Intraoperative Strategy

Hemangioblastomas (HBs) are rare, benign tumors often related to von Hippel-Lindau disease. They represent the most frequent primary cerebellar tumors in adults. Neurosurgical procedures aim to obtain a gross-total resection of tumor nodules, avoiding intra-postoperative hemorrhage. The introduction of new intraoperative imaging techniques has considerably changed surgical strategies in neuro-oncology. We present an overview of clinical and radiological data of a mono-institutional retrospective cohort, focusing on the role of intraoperative multimodal imaging in surgical strategy. From 2015 to 2021, we identified 64 (81%) cranial (42 cerebellar, 8 supratentorial, and 14 of the brainstem) HBs and 15 (19%) spinal (4 cervical and 11 dorsal) HBs in 79 patients. Intraoperatively, indocyanine green videoangiography with FLOW800 was used in 62 cases (52 cranial and 10 spinal), intraoperative ultrasound and contrast-enhanced ultrasounds in 22 cases (18 cranial and 4 spinal HBs), and fluorescein in 10 cases (in 6 cranial and 2 spinal cases used as SF-VA). Gross total resection was achieved in 100% of the cases (53 mural nodule removal and 26 complete resections of the solid tumor). No side effects were reported following the combination of these tools. Multimodal intraoperative techniques provide valuable and reliable information to identify the tumor and its vasculature, guiding a more precise and safer resection and reducing the risk of recurrence.

Fluorescein-guided resection of newly diagnosed high-grade glioma: Impact on extent of resection and outcome

Introduction

Maximal resection of high-grade glioma (HGG) improves progression-free survival (PFS) and overall survival (OS). Fluorescein sodium (FL) in combination with the YELLOW 560 ​nm filter (Carl Zeiss Meditec, Germany) is a safe and feasible method of visualizing residual tumor tissue during brain tumor resection.

Research question

We hypothesized that use of FL positively influenced the volumetric extent of resection (EOR), PFS, and OS in patients undergoing resection of a newly diagnosed HGG.

Materials and method

Using a prospective HGG registry, we identified 347 patients (median age 62.4 years; 141 women) with preoperative high-quality magnetic resonance images for volumetric analysis. Resection was performed under white light in n ​= ​151 (43.5%, white-light group) and under FL-guidance in n ​= ​196 (56.5%, FL group). Sex, age, presurgical Karnofsky Performance Index (KPI), O6-Methylguanin-DNA-Methyltransferase-Gene (MGMT) status, and adjuvant treatment modalities were well balanced between the groups. Volumetric analysis was performed by quantifying pre- and postoperative tumor volume based on gadolinium-enhanced T1 sequences in a blinded fashion.

Results

In the FL group, postoperative tumor volume was significantly smaller (p ​= ​0.003); accordingly, quantitative EOR was significantly larger (p ​= ​0.003). Significantly more complete resections were achieved in the FL group than in the white-light group (p ​= ​0.003). The FL group showed significantly longer PFS (p ​= ​0.020) and OS (p ​= ​0.015, log rank testing). Multivariate Cox regression modelling showed age, presurgical KPI, MGMT status, and FL-guided resection to be independent prognostic factors for survival.

Discussion and conclusion

Compared to white-light resection, FL-guided resection of newly diagnosed HGG significantly improved EOR and prolonged OS.

Intraoperative Tumor Detection Using Pafolacianine

Cancer is a leading cause of death worldwide, with increasing numbers of new cases each year. For the vast majority of cancer patients, surgery is the most effective procedure for the complete removal of the malignant tissue. However, relapse due to the incomplete resection of the tumor occurs very often, as the surgeon must rely primarily on visual and tactile feedback. Intraoperative near-infrared imaging with pafolacianine is a newly developed technology designed for cancer detection during surgery, which has been proven to show excellent results in terms of safety and efficacy. Therefore, pafolacianine was approved by the U.S. Food and Drug Administration (FDA) on 29 November 2021, as an additional approach that can be used to identify malignant lesions and to ensure the total resection of the tumors in ovarian cancer patients. Currently, various studies have demonstrated the positive effects of pafolacianine’s use in a wide variety of other malignancies, with promising results expected in further research. This review focuses on the applications of the FDA-approved pafolacianine for the accurate intraoperative detection of malignant tissues. The cancer-targeting fluorescent ligands can shift the paradigm of surgical oncology by enabling the visualization of cancer lesions that are difficult to detect by inspection or palpation. The enhanced detection and removal of hard-to-detect cancer tissues during surgery will lead to remarkable outcomes for cancer patients and society, specifically by decreasing the cancer relapse rate, increasing the life expectancy and quality of life, and decreasing future rates of hospitalization, interventions, and costs.

Fluorescein-guided surgery for the resection of pilocytic astrocytomas: A multicentric retrospective study

Objective

Pilocytic astrocytomas (PAs) are relatively benign tumors, usually enhancing on post-contrast MRI and often characterized by a mural nodule within a cystic component. Surgical resection represents the mainstay of treatment, and extent of resection (EOR) is associated with improved survival. In this study, we analyzed the effect of sodium fluorescein (SF) on the visualization and resection of these circumscribed astrocytic gliomas.

Methods

Surgical databases at two neurosurgical departments (Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy and Department of Neurosurgery, University Medical Center Regensburg, Regensburg, Germany) were retrospectively reviewed to identify the cohort of patients with pilocytic astrocytoma who had undergone fluorescein-guided tumor resection at any of the centers between March 2016 and February 2022. SF was intravenously injected (5 mg/kg) immediately after the induction of general anesthesia. Tumors were removed using a microsurgical technique with the YELLOW 560 filter (Carl Zeiss Meditec, Oberkochen, Germany).

Results

Forty-four patients (25 males and 19 females; 26 pediatric patients, mean age of 9.77 years, range 2 to 17 years; and 18 adult patients, mean age of 34.39 years, range 18 to 58 years) underwent fluorescein-guided surgery. No side effects related to SF occurred. In all tumors, contrast enhancement on preoperative MRI was correlated with intense, heterogeneous yellow fluorescence with bright fluorescent cystic fluid. Fluorescein was considered helpful in distinguishing tumors from viable tissue in all cases except three patients due to faint fluorescein enhancement. Biopsy was intended in two operations, and partial resection was intended in three operations. Gross total resection was achieved in 24 cases out of 39 patients scheduled for tumor removal (61.54%), in five cases a minimal residual volume was highlighted by postoperative MRI despite the intraoperative subjective evaluation of complete tumor removal (12.82%); in the other 10 cases, the resection was subtotal with fluorescent residual spots to avoid neurological worsening (25.64%).

Conclusions

The use of SF is a valuable method for safe fluorescence-guided tumor resection. Our data showed a positive effect of fluorescein-guided surgery on intraoperative visualization during resection of Pas, suggesting a possible role in improving the extent of resection of these lesions.

5-aminolevulinic acid and sodium fluorescein in IV ventricle ependymoma surgery: preliminary experience comparing the two techniques

Purpose

The aim of this study is to compare the use of 5-aminolevulinic acid (5-ALA) and sodium fluorescein (SF) in IV ventricular ependymoma (IVEP) surgical resection.

Methods

In this retrospective study, six patients with IVEP were enrolled. Gender ratio 2:1 male to female, with mean age 38.9 years old. A 5-ALA oral dose of 20 mg/kg and a SF intravenous dose of 2 mg/kg were administered. Telo-velar approach, operative microscope, and intraoperative monitoring were used in all the operations. We retrospectively compared the two fluorescence techniques at four steps during the surgical procedure: step 1: exposure of the tumor; step 2: dissection of the lesion from the cerebellum; step 3: assessment of the tumor borders and differentiation from normal tissue at the base of implants; and step 4: evaluation of possible residual tissue in the surgical cavity.

Results

At the first step, the ependymomas resulted well delineated by both fluorescent agents. In this step, 5-ALA was particularly helpful in the case of recurrent ependymoma. At step 2, 5-ALA provided a better identification of the ependymoma boundaries and distinction from cerebellum hemispheres than SF. In steps 3 and 4, SF was really helpful to detect tumor tissue.

Conclusion

According to our experience, fluorescence-guided surgery of IVEP with 5-ALA and SF is useful to maximize surgical resection with less risk of brainstem injury. Both fluorescence techniques are helpful in different steps of IVEP resection. However, further studies are needed to confirm our preliminary data.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10072-022-06012-z.

Detection improvement of gliomas in hyperspectral imaging of protoporphyrin IX fluorescence - in vitro comparison of visual identification and machine thresholds

BACKGROUND

5-aminolevulinic acid (5-ALA) - precursor of protoporphyrin IX (PpIX) - is utilized in fluorescence guided surgery (FGS) of high-grade gliomas. PpIX is used to identify traces of glioma during resection. Visual inspection of the fluorescence seems inaccurate in comparison to optic techniques such as hyperspectral imaging (HSI).

AIM

To characterize the limits of PpIX fluorescence detection of (i) visual evaluation and (ii) HSI analysis and to (iii) develop a classification system for visible and non-visible PpIX fluorescence.

METHODS

Samples with increasing concentrations (C) of PpIX and non-fluorescent controls were evaluated using a surgical microscope under blue light illumination. Similar samples were imaged with a HSI system tuned to PpIX fluorescence peak wavelength (635 nm) and control (RGB) channels. Samples' intensities were defined, leading to 96 analysed pixels after batching.

RESULTS

Three expert neurosurgeons assessed the PpIX samples (n = 16) and controls (n = 8) with unanimous decisions (ICC = 0.704), resulting in 63% recognition rate, 48% sensitivity, 92% specificity, 92% positive predictive value (PPV) and 47% negative predictive value (NPV). HSI image analysis, comparing mean relative values, resulted in 96%, 100%, 86%, 94%, 100%, respectively. Minimum PpIX concentration detection for experts was 0.6-1.8 μmol/l and HSI's 0.03-0.15 μmol/l.

CONCLUSIONS

PpIX concentrations of low-grade gliomas, and those reported on glioblastoma infiltration zones, are below experts' detection threshold. HSI analysis exceeds the performance of expert's visual inspection nearly by 20-fold. Hybrid FGS-HSI systems should be investigated in parallel to long-term outcomes. Described methods are applicable as a standard for calibration, testing and development of subvisual FGS techniques.

Supraorbital and mini-pterional keyhole craniotomies for brain tumors: a clinical and anatomical comparison of indications and outcomes in 204 cases

OBJECTIVE

The authors' objective was to compare the indications, outcomes, and anatomical limits of supraorbital (SO) and mini-pterional (MP) craniotomies in patients with intra- and extraaxial brain tumors, and to assess approach selection, utility of endoscopy, and surgical field overlap.

METHODS

A retrospective analysis was conducted of all brain tumor patients who underwent an SO or MP approach. The analyzed characteristics included pathology, endoscopy use, extent of resection, length of stay (LOS), and complications. On the basis of preoperative MRI data, tumor heatmaps were constructed to compare surgical access provided by both routes, including coronal projection heatmaps for parasellar tumors.

RESULTS

From 2007 to 2020, 158 patients underwent 173 (84.8%) SO craniotomies and 30 patients underwent 31 (15.2%) MP craniotomies; 71 (34.8%) procedures were reoperations. Of these 204 operations, 110 (63.6%) SO and 21 (67.7%) MP approaches were for extraaxial tumors (meningiomas in 65% and 76.2%, respectively). Gliomas and metastases together represented 84.1% and 70% of intraaxial tumors accessed with SO and MP approaches, respectively. Overall, 56.1% of tumors accessed with the SO approach and 41.9% of those accessed with the MP approach were in the parasellar region. Axial projection heatmaps showed that SO access extended along the entire ipsilateral and medial contralateral anterior cranial fossa, parasellar region, ipsilateral sylvian fissure, medial middle cranial fossa, and anterior midbrain, whereas MP access was limited to the ipsilateral middle cranial fossa, sylvian fissure, lateral parasellar region, and posterior aspect of anterior cranial fossa. Coronal projection heatmaps showed that parasellar access extended further superiorly with the SO approach compared with that of the MP approach. Endoscopy was utilized in 98 (56.6%) SO craniotomies and 7 (22.6%) MP craniotomies, with further tumor resection in 48 (49%) and 5 (71.4%) cases, respectively. Endoscope-assisted tumor removal was clustered in areas that were generally at farther distances from the craniotomy or in angled locations such as the cribriform plate region where microscopic visualization is limited. Gross-total or near-total resection was achieved in 120/173 (69%) SO approaches and 21/31 (68%) MP approaches. Major complications occurred in 11 (6.4%) SO approaches and 1 (3.2%) MP approach (p = 0.49). The median LOS decreased to 2 days in the last 2 years of the study.

CONCLUSIONS

This clinical experience suggests the SO and MP craniotomies are versatile, safe, and complementary approaches for tumors located in the anterior and middle cranial fossae and perisylvian and parasellar regions. The SO route, used in 85% of cases, achieved greater overall reach than the MP route. Both approaches may benefit from expanded visualization with endoscopy.

Application of sodium fluorescein for spinal cord lesions: intraoperative localization for tissue biopsy and surgical resection

Sodium fluorescein (NaFL) has been used to aid in the resection of primary and secondary lesions within the brain. Comparatively, there is limited research on clinical applications for lesions within the spinal cord. Fluorescein-guided microsurgery may increase the ability to localize and safely surgically treat spinal lesions. Twelve patients with spinal cord lesions received fluorescein sodium 10% (Alcon Laboratories INC, Fort Worth, TX, USA) at 3 mg/kg prior to surgical resection. Intraoperative visualization of fluorescence was performed using a Zeiss Pentero (Carl Zeiss AG, Oberkochen, Germany) microscope equipped with a Yellow560 filter or a Leica OH6 (Leica Microsystems, Wetzlar, Germany) equipped with a FL560 filter. Administration of NaFL resulted in lesional fluorescent contrast extravasation and facilitated surgical resection and localization in all twelve patients. In patients with a goal of complete resection, NaFL aided in complete resection of the spinal lesions in seven patients. In surgical resection patients, pathology was consistent with WHO grade I myxopapillary ependymoma in one patient, WHO grade II ependymoma in five patients, and nerve sheath tumor in one patient. In the other five patients, NaFL allowed for intraoperative tissue identification and successful tissue biopsy. In patients undergoing biopsy, tissue samples were positive for an intramedullary abscess, EBV-driven lymphoproliferative disease, and primary glial neoplasms. Fluorescein is a helpful microsurgical tool in guiding surgical resection and in the localization of intramedullary spinal lesions. Further research is necessary to explore fluorescein sodium applications in the resection of spinal cord lesions.

Safe Surgery for Glioblastoma: Recent Advances and Modern Challenges

One of the major challenges during glioblastoma surgery is balancing between maximizing extent of resection and preventing neurological deficits. Several surgical techniques and adjuncts have been developed to help identify eloquent areas both preoperatively (fMRI, nTMS, MEG, DTI) and intraoperatively (imaging (ultrasound, iMRI), electrostimulation (mapping), cerebral perfusion measurements (fUS)), and visualization (5-ALA, fluoresceine)). In this review, we give an update of the state-of-the-art management of both primary and recurrent glioblastomas. We will review the latest surgical advances, challenges, and approaches that define the onco-neurosurgical practice in a contemporary setting and give an overview of the current prospective scientific efforts.

Effect of 5-Aminolevulinic Acid and Sodium Fluorescein on the Extent of Resection in High-Grade Gliomas and Brain Metastasis

Surgery is essential in the treatment of high-grade gliomas (HGG) and gross total resection (GTR) is known to increase the overall survival and progression-free survival. Several studies have shown that fluorescence-guided surgery with 5-aminolevulinic acid (5-ALA) increases GTR considerably compared to white light surgery (65% vs. 36%). In recent years, sodium fluorescein (SF) has become an increasingly popular agent for fluorescence-guided surgery due to numerous utility benefits compared to 5-ALA, including lower cost, non-toxicity, easy administration during surgery and a wide indication range covering all contrast-enhancing lesions with disruption of the blood-brain barrier in the CNS. However, currently, SF is an off-label agent and the level of evidence for use in HGG surgery is inferior compared to 5-ALA. Here, we give an update and review the latest literature on fluorescence-guided surgery with 5-ALA and SF for brain tumors with emphasis on fluorescence-guided surgery in HGG and brain metastases. Further, we assess the advantages and disadvantages of both fluorophores and discuss their future perspectives.

Fluorescein-guided surgery for intradural spinal tumors: A single-center experience

•

Gross total removal has a pivotal role in surgical treatment of intradural spinal tumors.

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Sodium fluorescein prevents vascular injuries also preserving pial vessels in posterior myelotomy.

•

Fluorescence before the durotomy helps to distinguishing tumor from healthy tissue in intradural lesions.

•

Intraoperative fluorescence is safe and effective, also preserving functional anatomy in tumor removal.

Surgical advances in the management of brain metastases

As the epidemiological and clinical burden of brain metastases continues to grow, advances in neurosurgical care are imperative. From standard magnetic resonance imaging (MRI) sequences to functional neuroimaging, preoperative workups for metastatic disease allow high-resolution detection of lesions and at-risk structures, facilitating safe and effective surgical planning. Minimally invasive neurosurgical approaches, including keyhole craniotomies and tubular retractors, optimize the preservation of normal parenchyma without compromising extent of resection. Supramarginal surgery has pushed the boundaries of achieving complete removal of metastases without recurrence, especially in eloquent regions when paired with intraoperative neuromonitoring. Brachytherapy has highlighted the potential of locally delivering therapeutic agents to the resection cavity with high rates of local control. Neuronavigation has become a cornerstone of operative workflow, while intraoperative ultrasound (iUS) and intraoperative brain mapping generate real-time renderings of the brain unaffected by brain shift. Endoscopes, exoscopes, and fluorescent-guided surgery enable increasingly high-definition visualizations of metastatic lesions that were previously difficult to achieve. Pushed forward by these multidisciplinary innovations, neurosurgery has never been a safer, more effective treatment for patients with brain metastases.

A Structure-Activity Relationship Study of Bimodal BODIPY-Labeled PSMA-Targeting Bioconjugates

The aim of this study was to identify a high-affinity BODIPY peptidomimetic that targets the prostate-specific membrane antigen (PSMA) as a potential bimodal imaging probe for prostate cancer. For the structure-activity study, several BODIPY (difluoroboron dipyrromethene) derivatives with varying spacers between the BODIPY dye and the PSMA Glu-CO-Lys binding motif were prepared. Corresponding affinities were determined by competitive binding assays in PSMA-positive LNCaP cells. One compound was identified with comparable affinity (IC50 =21.5±0.1 nM) to Glu-CO-Lys-Ahx-HBED-CC (PSMA-11) (IC50 =18.4±0.2 nM). Radiolabeling was achieved by Lewis-acid-mediated 19 F/18 F exchange in moderate molar activities (∼0.7 MBq nmol-1 ) and high radiochemical purities (>99 %) with mean radiochemical yields of 20-30 %. Cell internalization of the 18 F-labeled high-affinity conjugate was demonstrated in LNCaP cells showing gradual increasing PSMA-mediated internalization over time. By fluorescence microscopy, localization of the high-affinity BODIPY-PSMA conjugate was found in the cell membrane at early time points and also in subcellular compartments at later time points. In summary, a high-affinity BODIPY-PSMA conjugate has been identified as a suitable candidate for the development of PSMA-specific dual-imaging agents.

In Situ Side-to-Side Pericallosal-Pericallosal Artery and Callosomarginal-Callosomarginal Artery Bypasses for Complex Distal Anterior Cerebral Artery Aneurysms: A Technical Note

BACKGROUND

Despite surgical and endovascular technical improvements over the last decades, the treatment of complex aneurysms of the distal anterior cerebral artery (ACA) is very challenging for both vascular neurosurgeons and interventional neuroradiologists. Furthermore, the interpersonal anatomic variability requires, most of the time, a tailored planning.

OBJECTIVE

To describe a novel technique of bypasses in the territory of ACA to protect the brain territory distal to the aneurysm.

METHODS

A 53-yr-old male with a large complex fusiform aneurysm of the left distal A2 segment of the ACA, involving the origin of the callosomarginal and pericallosal arteries, was judged not suitable for a single procedure (endovascular or neurosurgical). Two side-to-side bypasses were performed in a single surgery to connect the pericallosal and callosomarginal arteries of both sides, distally to the aneurysm. Subsequently, an endovascular embolization of the aneurysm was achieved with coils.

RESULTS

The patency of the microanastomoses, performed in the anterior interhemispheric fissure, was positively evaluated intraoperatively with indocyanine green and fluorescein videoangiography. The aneurysm sac, together with proximal A2 segment, was completely occluded with platinum coils. At the last follow-up, computed tomography angiography confirmed the patency of both bypasses, without any sign of aneurysm recanalization. The patients never complained of any focal neurological deficits or worsening of clinical status.

CONCLUSION

We present an elegant and innovative solution to completely protect the distal ACA territory in cases of complex aneurysm involving the origin of both callosomarginal and pericallosal arteries.

Fluorescence-Guided Surgery: A Review on Timing and Use in Brain Tumor Surgery

Fluorescence-guided surgery (FGS) allows surgeons to have improved visualization of tumor tissue in the operating room, enabling maximal safe resection of malignant brain tumors. Over the past two decades, multiple fluorescent agents have been studied for FGS, including 5-aminolevulinic acid (5-ALA), fluorescein sodium, and indocyanine green (ICG). Both non-targeted and targeted fluorescent agents are currently being used in clinical practice, as well as under investigation, for glioma visualization and resection. While the efficacy of intraoperative fluorescence in studied fluorophores has been well established in the literature, the effect of timing on fluorophore administration in glioma surgery has not been as well depicted. In the past year, recent studies of 5-ALA use have shown that intraoperative fluorescence may persist beyond the previously studied window used in prior multicenter trials. Additionally, the use of fluorophores for different brain tumor types is discussed in detail, including a discussion of choosing the right fluorophore based on tumor etiology. In the following review, the authors will describe the temporal nature of the various fluorophores used in glioma surgery, what remains uncertain in FGS, and provide a guide for using fluorescence as a surgical adjunct in brain tumor surgery.

In Silico Mathematical Modelling for Glioblastoma: A Critical Review and a Patient-Specific Case

Glioblastoma extensively infiltrates the brain; despite surgery and aggressive therapies, the prognosis is poor. A multidisciplinary approach combining mathematical, clinical and radiological data has the potential to foster our understanding of glioblastoma evolution in every single patient, with the aim of tailoring therapeutic weapons. In particular, the ultimate goal of biomathematics for cancer is the identification of the most suitable theoretical models and simulation tools, both to describe the biological complexity of carcinogenesis and to predict tumor evolution. In this report, we describe the results of a critical review about different mathematical models in neuro-oncology with their clinical implications. A comprehensive literature search and review for English-language articles concerning mathematical modelling in glioblastoma has been conducted. The review explored the different proposed models, classifying them and indicating the significative advances of each one. Furthermore, we present a specific case of a glioblastoma patient in which our recently proposed innovative mechanical model has been applied. The results of the mathematical models have the potential to provide a relevant benefit for clinicians and, more importantly, they might drive progress towards improving tumor control and patient's prognosis. Further prospective comparative trials, however, are still necessary to prove the impact of mathematical neuro-oncology in clinical practice.

Brain Tumor Resection in Elderly Patients: Potential Factors of Postoperative Worsening in a Predictive Outcome Model

Simple Summary

Brain tumor surgery in older patients is becoming more relevant, considering that the proportion of older adults being treated for cancer is rising, whereas some pivotal studies in neuro-oncology comprised young patients only. The knowledge of possible predictors of outcome should be included in the preoperative assessment to make the best possible decision in terms of management. We present a case series of 143 patients older than 65 years, intending to identify the possible factors predicting the risk of clinical worsening after elective surgical resection of intracranial tumors in elderly patients. We found that postoperative complications occurrence and preoperative surgical complexity significantly influence the outcome in this subgroup of patients, whereas postoperative complications were the only factor with an impact also at long-term follow-up.

Abstract

The decision of whether to operate on elderly patients with brain tumors is complex, and influenced by pathology-related and patient-specific factors. This retrospective cohort study, based on a prospectively collected surgical database, aims at identifying possible factors predicting clinical worsening after elective neuro-oncological surgery in elderly patients. Therefore, all patients ≥65 years old who underwent BT resection at a tertiary referral center between 01/2018 and 12/2019 were included. Age, smoking, previous radiotherapy, hypertension, preoperative functional status, complications occurrence, surgical complexity and the presence of comorbidities were prospectively collected and analyzed at discharge and the 3-month follow-up. The series included 143 patients (mean 71 years, range 65–86). Sixty-five patients (46%) had at least one neurosurgical complication, whereas 48/65 (74%) complications did not require invasive treatment. Forty-two patients (29.4%) worsened at discharge; these patients had a greater number of complications compared to patients with unchanged/improved performance status. A persistent worsening at three months of follow-up was noted in 20.3% of patients; again, this subgroup presented more complications than patients who remained equal or improved. Therefore, postoperative complications and surgical complexity seem to influence significantly the early outcome in elderly patients undergoing brain tumor surgery. In contrast, postoperative complications alone are the only factor with an impact on the 3-month follow-up.

The Management of Brain Metastases-Systematic Review of Neurosurgical Aspects

The multidisciplinary management of patients with brain metastases (BM) consists of surgical resection, different radiation treatment modalities, cytotoxic chemotherapy, and targeted molecular treatment. This review presents the current state of neurosurgical technology applied to achieve maximal resection with minimal morbidity as a treatment paradigm in patients with BM. In addition, we discuss the contribution of neurosurgical resection on functional outcome, advanced systemic treatment strategies, and enhanced understanding of the tumor biology.

Fluorescence guided surgery for pituitary adenomas

PURPOSE

Resection of pituitary adenomas presents a number of unique challenges in neuro-oncology. The proximity of these lesions to key vascular and endocrine structures as well as the need to interpret neuronavigation in the context of shifting tumor position increases the complexity of the operation. More recently, substantial advances in fluorescence-guided surgery have been demonstrated to facilitate the identification of numerous tumor types and result in increased rates of complete resection and overall survival.

METHODS

A review of the literature was performed, and data regarding the mechanism of the fluorescence agents, their administration, and intraoperative tumor visualization were extracted. Both in vitro and in vivo studies were assessed. The application of these agents to pituitary tumors, their advantages and limitations, as well as future directions are presented here.

RESULTS

Numerous laboratory and clinical studies have described the use of 5-ALA, fluorescein, indocyanine green, and OTL38 in pituitary lesions. All of these drugs have been demonstrated to accumulate in tumor cells. Several studies have reported the successful use of the majority of the agents in inducing intraoperative tumor fluorescence. However, their sensitivity and specificity varies across the literature and between functioning and non-functioning adenomas.

CONCLUSIONS

At present, numerous studies have shown the feasibility and safety of these agents for pituitary adenomas. However, further research is needed to assess the applicability of fluorescence-guided surgery across different tumor subtypes as well as explore the relationship between their use and postoperative clinical outcomes.

Sodium Fluorescein for Spinal Intradural Tumors

Technological innovations in spinal intradural tumor surgery simplify treatment. Surgical treatment of cranial benign and malignant pathologies under microscope with sodium (Na)-fluorescein guidance has often been reported, but few studies have focused on spinal intradural tumors. We aimed to investigate the usefulness of Na-fluorescein under yellow filter in intradural spinal tumor surgery by retrospectively reviewing cases involving intramedullary and extramedullary tumors operated under the guidance of Na-fluorescein. Forty-nine adult patients with a diagnosis of spinal intradural tumor operated under a yellow filter (560 nm) microscope using Na-fluorescein dye were included in the study. Demographic data, such as age and sex, neurological status, extent of tumor resection, histopathological diagnosis, Na-fluorescein staining pattern, and its usefulness during surgery were noted and statistically analyzed. Of all recruited patients, 26 women (53.1%) and 23 men (46.9%), were included for analysis. The age range of the patients was 18–64 years, with a mean age of 41.6 ± 13.9. An intradural intramedullary mass was found in 30.6% (n = 15) of the patients, and an intradural extramedullary mass in 69.4% (n: 34). While Na-fluorescein staining was homogeneous in all intradural extramedullary tumors, 73.3% (n: 11) of intradural intramedullary tumors were homogeneous, and 13.3% (n: 2) moderately heterogeneous. In the whole study group, the Na-fluorescein staining pattern was helpful in surgical resection in 47 cases (95.9%). While 34/34 (100%) found it helpful for extramedullary tumors, 13/15 (86.7%) did in intramedullary tumors, and for 2/15 (13.3%) it was not. In conclusion, Na-fluorescein helps in distinguishing tumor from healthy tissue in intradural extramedullary and intramedullary tumor surgery under a yellow filter microscope in most cases, thus providing convenient assistance to surgeons.

Fluorescein Sodium-Guided Neuroendoscopic Resection of Deep-Seated Malignant Brain Tumors: Preliminary Results of 18 Patients

BACKGROUND

Deep-seated intracranial lesions are challenging to resect completely and safely. Fluorescence-guided surgery (FGS) promotes the resection of malignant brain tumors (MBTs). Classically, FGS is performed using microscope equipped with a special filter. Fluorescence-guided neuroendoscopic resection of deep-seated brain tumors has not been reported yet.

OBJECTIVE

To evaluate the feasibility, safety, and effectiveness of the fluorescence-guided neuroendoscopic surgery in deep-seated MBTs.

METHODS

A total of 18 patients with high-grade glioma (HGG) and metastatic tumor (MT) underwent fluorescein sodium (FS)-guided neuroendoscopic surgery. Tumor removal was carried out using bimanual microsurgical techniques under endoscopic view. The degree of fluorescence staining was classified as "helpful" and "unhelpful" based on surgical observation. Extent of resection was determined using magnetic resonance imaging (MRI). Karnofsky Performance Status (KPS) score was used for evaluation of general physical performances of patients.

RESULTS

A total of 11 patients had HGG, and 7 had MT. No technical difficulty was encountered regarding the use of endoscopic technique. "Helpful" fluorescence staining was observed in 16 patients and fluorescent tissue was completely removed. Postoperative MRI confirmed gross total resection (88.9%). In 2 patients, FS enhancement was not helpful enough for tumor demarcation and postoperative MRI revealed near total resection (11.1%). No complication, adverse events, or side effects were encountered regarding the use of FS. KPS score of patients was improved at 3-mo follow-up.

CONCLUSION

FS-guided endoscopic resection is a feasible technique for deep-seated MBTs. It is safe, effective, and allows for a high rate of resection. Future prospective randomized studies are needed to confirm these preliminary data.

Intraoperative Confocal Laser Endomicroscopy Ex Vivo Examination of Tissue Microstructure During Fluorescence-Guided Brain Tumor Surgery

Background

Noninvasive intraoperative optical biopsy that provides real-time imaging of histoarchitectural (cell resolution) features of brain tumors, especially at the margin of invasive tumors, would be of great value. To assess clinical-grade confocal laser endomicroscopy (CLE) and to prepare for its use intraoperatively in vivo, we performed an assessment of CLE ex vivo imaging in brain lesions.

Methods

Tissue samples from patients who underwent intracranial surgeries with fluorescein sodium (FNa)–based wide-field fluorescence guidance were acquired for immediate intraoperative ex vivo optical biopsies with CLE. Hematoxylin-eosin–stained frozen section analysis of the same specimens served as the gold standard for blinded neuropathology comparison. FNa 2 to 5 mg/kg was administered upon induction of anesthesia, and FNa 5 mg/kg was injected for CLE contrast improvement. Histologic features were identified, and the diagnostic accuracy of CLE was assessed.

Results

Of 77 eligible patients, 47 patients with 122 biopsies were enrolled, including 32 patients with gliomas and 15 patients with other intracranial lesions. The positive predictive value of CLE optical biopsies was 97% for all specimens and 98% for gliomas. The specificity of CLE was 90% for all specimens and 94% for gliomas. The second FNa injection in seven patients, a mean of 2.6 h after the first injection, improved image quality and increased the percentage of accurately diagnosed images from 67% to 93%. Diagnostic CLE features of lesional glioma biopsies and normal brain were identified. Seventeen histologic features were identified.

Conclusions

Results demonstrated high specificity and positive predictive value of ex vivo intraoperative CLE optical biopsies and justify an in vivo intraoperative trial. This new portable, noninvasive intraoperative imaging technique provides diagnostic features to discriminate lesional tissue with high specificity and is feasible for incorporation into the fluorescence-guided surgery workflow, particularly for patients with invasive brain tumors.

The Supraorbital Eyebrow Craniotomy for Intra- and Extra-Axial Brain Tumors: A Single-Center Series and Technique Modification

BACKGROUND

The supraorbital (SO) eyebrow craniotomy provides minimally invasive access to the anterior and middle fossae and parasellar region.

OBJECTIVE

To present a series of patients treated with the SO approach to assess outcomes, the impact of endoscopy, and describe a modified pericranial flap aimed at reducing postoperative frontalis paresis and hypesthesia.

METHODS

A retrospective analysis was undertaken of our prospective database of patients who underwent SO craniotomy for tumor/cyst removal. Patients were evaluated based on pathology, utility of endoscopy, extent of resection, complications, and functional/esthetic recovery.

RESULTS

From 2007 to 2018, 129 operations were performed in 117 patients (54% women; mean age 60 ± 16.5 yr). The most common lesions were meningiomas (43%), gliomas (15%), and metastases (15%). Prior surgery and/or radiation had been performed in 37% and 26% of patients, respectively. Endoscopy was used in 76 (61%) operations and allowed more complete tumor removal in 38 (50%). For first-time operations, gross-total removal was achieved in 78%. Major complications included stroke (3%), cranial nerve deficit (3%), acute hematoma (1%), and cerebrospinal fluid leak (1%). The modified pericranial flap technique used in 18 recent patients resulted in a shorter duration of transient frontalis paresis and forehead hypesthesia with complete functional recovery in all 18.

CONCLUSION

The SO craniotomy is an effective keyhole approach for intra- and extra-axial tumors. Endoscopic assistance may allow additional tumor removal in almost 30% of the cases. The modified pericranial flap appears to accelerate functional recovery, although additional patients and follow-up are required to better assess this technique.

Blood-Brain Barrier, Blood-Brain Tumor Barrier, and Fluorescence-Guided Neurosurgical Oncology: Delivering Optical Labels to Brain Tumors

Recent advances in maximum safe glioma resection have included the introduction of a host of visualization techniques to complement intraoperative white-light imaging of tumors. However, barriers to the effective use of these techniques within the central nervous system remain. In the healthy brain, the blood-brain barrier ensures the stability of the sensitive internal environment of the brain by protecting the active functions of the central nervous system and preventing the invasion of microorganisms and toxins. Brain tumors, however, often cause degradation and dysfunction of this barrier, resulting in a heterogeneous increase in vascular permeability throughout the tumor mass and outside it. Thus, the characteristics of both the blood-brain and blood-brain tumor barriers hinder the vascular delivery of a variety of therapeutic substances to brain tumors. Recent developments in fluorescent visualization of brain tumors offer improvements in the extent of maximal safe resection, but many of these fluorescent agents must reach the tumor via the vasculature. As a result, these fluorescence-guided resection techniques are often limited by the extent of vascular permeability in tumor regions and by the failure to stain the full volume of tumor tissue. In this review, we describe the structure and function of both the blood-brain and blood-brain tumor barriers in the context of the current state of fluorescence-guided imaging of brain tumors. We discuss features of currently used techniques for fluorescence-guided brain tumor resection, with an emphasis on their interactions with the blood-brain and blood-tumor barriers. Finally, we discuss a selection of novel preclinical techniques that have the potential to enhance the delivery of therapeutics to brain tumors in spite of the barrier properties of the brain.

Fluorescein-mediated sonodynamic therapy in a rat glioma model

INTRODUCTION

Malignant gliomas have a dismal prognosis and significant efforts are being made to develop more effective treatments. Sonodynamic therapy (SDT) is an emerging modality for cancer treatment which combines ultrasound with sonosensitizers to produce a localized cytotoxic effect. The aim of this study is to demonstrate the efficacy of SDT with fluorescein (FL) and low-intensity focused ultrasound in inhibiting the growth of ectopic gliomas implanted in the rat's subcutaneous tissue.

METHODS

In vivo cytotoxicity of FL-SDT was evaluated in C6 rat glioma cells which were inoculated subcutaneously. Tumor specific extracellular FL extravasation and accumulation was assessed with IVIS imaging in rats receiving systemic FL. Effects of FL-SDT with focused low-intensity ultrasound on tumor growth, and histological features of the rat's tumors were investigated. Treatment related apoptosis and necrosis were analyzed using hematoxylin & eosin, and apoptosis-specific staining.

RESULTS

IVIS imaging revealed a high degree of FL accumulation within the tumor, with a nearly threefold increase in tumoral epifluorescence signal over background. SDT significantly inhibited outgrowth of ectopic C6 gliomas across all three FUS exposure conditions. TUNEL and active caspase-3 staining did not reveal conclusive trends across control and SDT condition for apoptosis.

CONCLUSION

Our results suggest that SDT with FL and low-intensity FUS is effective in inhibiting the growth of ectopic malignant gliomas in rats. The selective FL extravasation and accumulation in the tumor areas where the blood-brain barrier is damaged suggests the tumor-specificity of the treatment. The possibility to use this treatment in intracranial models and in human gliomas will have to be explored in further studies.