Fluorescence-guided resection with 5-aminolevulinic Acid of subependymomas of the fourth ventricle: report of 2 cases: technical case report

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.

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.

The Neurosurgeon's Armamentarium for Gliomas: An Update on Intraoperative Technologies to Improve Extent of Resection

Maximal safe resection is the standard of care in the neurosurgical treatment of high-grade gliomas. To aid surgeons in the operating room, adjuvant techniques and technologies centered around improving intraoperative visualization of tumor tissue have been developed. In this review, we will discuss the most advanced technologies, specifically fluorescence-guided surgery, intraoperative imaging, neuromonitoring modalities, and microscopic imaging techniques. The goal of these technologies is to improve detection of tumor tissue beyond what conventional microsurgery has permitted. We describe the various advances, the current state of the literature that have tested the utility of the different adjuvants in clinical practice, and future directions for improving intraoperative technologies.

Image-Guided Brain Surgery

In neurosurgery, the extent of resection plays a critical role, especially in the management of malignant gliomas. These tumors are characterized through a diffuse infiltration into the surrounding brain parenchyma. Delineation between tumor and normal brain parenchyma can therefore often be challenging. During the recent years, several techniques, aiming at better intraoperative tumor visualization, have been developed and implemented in the field of brain tumor surgery. In this chapter, we discuss current strategies for intraoperative imaging in brain tumor surgery, comprising conventional techniques such as neuronavigation, techniques using fluorescence-guided surgery, and further highly precise developments such as targeted fluorescence spectroscopy or Raman spectroscopy.

Is Visible Aminolevulinic Acid-Induced Fluorescence an Independent Biomarker for Prognosis in Histologically Confirmed (World Health Organization 2016) Low-Grade Gliomas?

BACKGROUND

Approximately 20% of low-grade gliomas (LGG) display visible protoporphyrin fluorescence during surgery after 5-aminolevulinic acid (5-ALA) administration.

OBJECTIVE

To determine if fluorescence represents a prognostic marker in LGG.

METHODS

Seventy-four consecutive patients with LGG (World Health Organization 2016) were operated on with 5-ALA. Fluorescent tissue was specifically biopsied. Tumor size, age, Karnofsky index, contrast-enhancement, fluorescence, and molecular factors (IDH1/IDH2-mutations, Ki67/MIB1 Index, 1p19q codeletions, ATRX, EGFR, p53 expression, and O⁶-methylguanine DNA methyltransferase promotor methylation), were related to progression-free survival (PFS), malignant transformation-free survival (MTFS) and overall survival (OS).

RESULTS

Sixteen of seventy-four LGGs (21.6%) fluoresced. Fluorescence was partially related to weak enhancement on magnetic resonance imaging and increased (positron emission tomography)PET-FET uptake, but not to Karnofsky Performance Score, tumor size, or age. Regarding molecular markers, only EGFR expression differed marginally (fluorescing vs nonfluorescing: 19% vs 5%; P = .057). Median follow-up was 46.4 mo (95% confidence interval [CI]: 41.8-51.1). PFS, MTFS, and OS were shorter in fluorescing tumors (PFS: median 9.8 mo, 95% CI: 1.00-27.7 vs 45.8, 31.9-59.7, MTFS: 43.0 [27.5-58.5] vs 64.6 [57.7-71.5], median not reached, P = .015; OS: 51.6, [34.8-68.3] vs [68.2, 62.7-73.8], P = .002). IDH mutations significantly predicted PFS, MTFS, and OS. In multivariate analysis IDH status and fluorescence both independently predicted MTFS and OS. PFS was not independently predicted by fluorescence.

CONCLUSION

This is the first report investigating the role of ALA-induced fluorescence in histologically confirmed LGG. Fluorescence appeared to be a marker for inherent malignant transformation and OS, independently of known prognostic markers. Fluorescence in LGG might be taken into account when deciding on adjuvant therapies.

5-ALA fluorescence on tumors different from malignant gliomas. Review of the literature and our experience

INTRODUCTION

Fluorescence guided surgery with 5-aminolevulinic acid (5-ALA) is a well-established technique for improving resection of malignant cerebral glioma. In recent years, this technique is being increasingly applied off label to other brain tumor entities such as Low-grade glioma, meningioma, metastases, lymphoma and other central nervous system tumors. In this paper We collected all the data of 5-ALA guided surgery in "not malignant glioma" in literature compared to our experience.

EVIDENCE ACQUISITION

We searched the PubMed/Medline database all clinical series reporting 5-ALA guided-surgery in not malignant glioma. We reviewed all data also showing our experience.

EVIDENCE SYNTHESIS

Fluorescence guided surgery with 5-ALA might be helpful not only in high-grade glioma but also in other brain tumor especially in Low grade glioma with a suspect of anaplastic spot, meningioma with bone invasion or parenchymal infiltration, ependymoma, lymphoma and pediatric tumors.

CONCLUSIONS

Due to the relatively few number or clinical studies, prospective clinical trials are needed to increase the overall level of evidence concerning the usage of 5-ALA in CNS tumors different from high-grade glioma. Furthermore, a greater us of new tools such as, spectroscopy or confocal microscope or the use of combination of other fluorescence could make more effective this technique.

Established and emerging uses of 5-ALA in the brain: an overview

INTRODUCTION

5-aminolevulinic acid (5-ALA) was approved by the FDA in June 2017 as an intra-operative optical imaging agent for patients with gliomas (suspected World Health Organization Grades III or IV on preoperative imaging) as an adjunct for the visualization of malignant tissue during surgery. 5-ALA fluorescence-guided surgery (FGS) has been in widespread use in Europe and other continents since 2007.

METHODS

We reviewed the data available and summarize the most important known uses of 5-ALA FGS and its potential future applications.

RESULTS/CONCLUSIONS

The technique has been extensively studied, and more than 300 papers have been published on this topic. Visualization of high-grade glioma tissue is robust and reproducible, and can impact the extent of tumor resection and patient outcomes. 5-ALA FGS for other kind of tumors needs further development.

Fluorescence Guided Surgery with 5-Aminolevulinic Acid for Resection of Spinal Cord Ependymomas

STUDY DESIGN

A retrospective study.

PURPOSE

We report our experience with 5-aminolevulinic acid (5-ALA)-assisted resection of spinal cord ependymomas in adults.

OVERVIEW OF LITERATURE

Ependymoma is the most frequent primary spinal cord tumor in adults. Surgery is the treatment of choice in most cases. However, while complete resection is achieved in approximately 80% of cases, clinical improvement is achieved in 15% only. Five-ALA fluorescence-guided surgery seems to be useful for this tumor type.

METHODS

We studied 14 patients undergoing 5-ALA fluorescence-guided surgery for spinal cord ependymomas in our service. The modified McCormick classification was used to determine clinical status and the degree of resection was assessed with magnetic resonance imaging.

RESULTS

Of the 14 patients, the tumor showed an intense emission of fluorescence in 12 and the fluorescence was weak and nonuniform in two. Complete resection was achieved in 11 cases. According to the McCormick classification, 10 patients improved, two remained the same, and two deteriorated.

CONCLUSIONS

Our results confirm that 5-ALA fluorescence-guided resection is useful in spinal cord ependymoma resection. Although the rate of complete resections is similar to that in published series without 5-ALA, clinical results are better when using 5-ALA with a lower percentage of clinical deterioration.

Fluorescence guided resection with 5-aminolevulinic acid of a pilomyxoid astrocytoma of the third ventricle

Fluorescence-guided resection with 5-aminolevulinic acid has been shown to be useful in the resection of certain brain tumors other than high grade gliomas, facilitating the intraoperative differentiation of neoplastic tissue. The technique enables the surgeon to ensure that no tumor fragments remain, thereby achieving higher rates of complete resection. Tihan first described pilomyxoid astrocytomas in 1999. They are currently classified as grade II astrocytoma according to the WHO classification system and, because of their tendency to recur and their dissemination through the cerebrospinal fluid pathways, they are considered to be more aggressive than pilocytic astrocytoma. As a result, management of these tumors must be more aggressive, always aiming for complete macroscopic resection whenever possible. In this article, we present a case of pilomyxoid astrocytoma of the third ventricle in which the use of fluorescence-guided resection with 5-ALA facilitated complete resection. Imaging tests performed after five years revealed no signs of recurrence and no adjuvant radiotherapy or chemotherapy was required. This article also comprises a review of the literature concerning the characteristics and management of this tumor, which was recently considered to be a different histopathological entity.

5-ALA fluorescence-guided endoscopic surgery for mixed germ cell tumors

5-Aminolevulinic acid (5-ALA) fluorescence-guided surgery is widely used for detection and planning of resection of malignant gliomas and other brain tumors. However, no reports have described 5-ALA fluorescence-guided surgery or direct visualization of germ cell tumors. Here, we report two cases of germ cell tumors in which a positive 5-ALA fluorescent signal was visualized with a neuroendoscope. Both cases had a tumor in the pineal region that was associated with hydrocephalus. The patients underwent surgery after administration of 5-ALA. After ventricular puncture of the anterior horn, we could observe the ventricular wall and tumor using the Karl Storz Photodynamic diagnosis system endoscope. Then, biopsy of the pineal tumor and endoscopic third ventriculostomy were performed in both cases. In case 1, a 22-year-old man, part of the ventricular wall and tumor tissue showed red fluorescence. In case 2, a 16-year-old man, part of the fornix and infundibular recess showed red fluorescence, and the tumor showed relatively weak red fluorescence. The histopathological diagnosis of both cases was pure germinoma. This is the first report of direct visualization of mixed germinomas with 5-ALA fluorescence-guided endoscopic surgery. This method not only allows visualization of the tumor mass, but may also be useful for detailed observation in the ventricular wall.