Article
5-ALA for the fluorescence-guided resection of primary and secondary brain tumours – observational insights in an augmented reality setting
5-ALA fluoreszenz-kontrollierte Entfernung von primären und sekundären Hirntumorenmit Unterstützungaugmentierter Realität
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Authors
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Phileas Proskynitopoulos
- Kliniken der Stadt Köln, Klinik für Neurochirurgie, Köln, Deutschland
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Makoto Nakamura
- Kliniken der Stadt Köln, Klinik für Neurochirurgie, Köln, Deutschland
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Axel Heimann
- Universitätsmedizin Mainz, Institut für Neurochirurgische Pathophysiologie, Mainz, Deutschland
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Patra Charalampaki
- Kliniken der Stadt Köln, Klinik für Neurochirurgie, Köln, Deutschland
| Published: | June 26, 2020 |
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Outline
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Objective: Fluorescence-guided surgery with the use of five-aminolaevulinic acid (5 -ALA) is the state-of-the-art treatment of high-grade gliomas. However, intraoperative visualization of 5-ALA under violet light remains challenging, especially when blood covers parts of the surgical field, thereby masquing fluorescence. Apart from that, continuous switching between the light modes has a negative effect on operation ergonomy. To overcome these problems and combine the brightness of visible light with the information delivered by 5-ALA fluorescence, we implemented multispectral fluorescence (MFL) in a microscope, a technique that is able to project both information in real-time to the surgeon.
Methods: After observational testing of the software on 3 rats, we examined 25 patients with primary and secondary brain tumors who underwent surgery using the MFL technique. One patient was operated on two different regions and lesions in the same setting. The tumors comprised of 6 glioblastomas, 4 anaplastic astrocytomas, 1 anaplastic oligodendroglioma, 2 meningiomas, 11 metastatic tumors, 1 acoustic neuroma, and 1 ependymoma. The MFL technique with the real-time overlay of 5-ALA fluorescence and white light was compared intraoperatively to the classic blue filter detecting 5-ALA fluorescence.
Results: The lesion was, in all cases, clearly visible and highlighted from the surrounding tissues. The pseudocolor we chose to visualize the lesion was green, representing 5-ALA fluorescence, with the surrounding brain tissue remaining in its original white color. In the cases where blood was covering the surgical field, orientation was easy to maintain, due to the additional information delivered from the white light image.
Conclusion: The MFL technique opens the way for precise and clear visualization of tumor 5-ALA fluorescence in real-time under white light. It can be easily implemented in the resection of all tumors accumulating 5-ALA. Drawbacks of classic 5-ALA fluorescence such as hidden fluorescence because of overlying blood could be overcome with the presence of additional white light and the clear visualization of the exposed brain. Furthermore, this new technique is a promising tool with the potential to significantly improve operation ergonomy.
Figure 1 [Fig. 1]
