Fluorescein guided surgery for malignant brain tumors: case series with a custom made device

Introduction: Gross total resection for malignant brain neoplasms is an important oncological principle and a major part of the treatment with crucial impact on prognosis. It is a challenge due to the heterogeneity of these lesions and its infiltration in eloquent areas. Some resources are useful to maximize the extension with safety and minimal sequelae. Fluorescein guided surgery is a safe, cheap and important tool that improves the rate of total resection. We present a case series in which fluorescein is used in surgeries for malignant gliomas and metastasis.

Methods: We have built a 3D printed device with an excitation and a barrier filter to use in surgical microscopes. The patients received an intravenous dose of 5 mg/kg of sodium fluorescein before skin incision. Surgical view under white light was compared to the use of the light filters.

Results: Fluorescein is an organic dye widely and safely used in humans. It requires a blue light source and an interposition of a yellow filter to see it properly. It is a highly fluorescent molecule and is excited by light with a wavelength between 465 and 490 nm and has a peak emission between 520 and 530 nm. This substance accumulates where the blood brain barrier is broken. It has been used in central nervous system lesions such as metastasis, high grade gliomas and skull base tumors. In all our cases with the use of our device the tumors showed a high fluorescence, but not in the normal surrounding brain. This tool makes easier to identify the lesion and to achieve gross total resection with minimum damage to neighboring tissue.

Conclusion: Fluorescence guided surgery increases the rate of gross total resection of malignant brain tumors to up to 80% in some series. This is an important tool with a potential impact on overall survival of the patients. This is a low-cost option that could make this technology available in low resources areas.