Article
Impact of 5-ALA in meningioma resection grading
Einfluss von 5-ALA auf den Meningiome-Resektionsgrad
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Authors
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Guilherme Ramina Montibeller
- Neurological Institute of Curitiba - INC, Department of Neurosurgery, Curitiba, Brasilien
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Gustavo Simiano Jung
- Neurological Institute of Curitiba - INC, Department of Neurosurgery, Curitiba, Brasilien
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Guilherme Augusto de Souza Machado
- Neurological Institute of Curitiba - INC, Department of Neurosurgery, Curitiba, Brasilien
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Marcela Santos Cavalcanti
- Neopath, Curitiba, Brasilien; Neurological Institute of Curitiba - INC, Department of Neuropathology, Curitiba, Brasilien
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Erasmo Barros da Silva Junior
- Neurological Institute of Curitiba - INC, Department of Neurosurgery, Curitiba, Brasilien
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Ricardo Ramina
- Neurological Institute of Curitiba - INC, Department of Neurosurgery, Curitiba, Brasilien
| Published: | June 4, 2021 |
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Outline
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Objective: Recurrence after meningioma surgery may occur even after complete tumor resection (Simpson grade I). One possible cause may be the presence of remnant tumor cells that were left behind and not identified using microscope`s white light. Almost all meningiomas are aminolevulinic acid (5-ALA) positive. Fluorescence-guided resection of these tumors may discover small tumor remnants in some cases. The objectives of this study are to evaluate the possible advantages of using 5-ALA during meningioma surgery, reconsider the total resection concept and propose an adaptation of the Simpson Grading System.
Methods: Thirty two patients (36 tumors) with intracranial meningiomas in different locations were operated on using 5-ALA administered per os. At the end of the surgery, when total resection was supposed under microscope’s white light, final inspection was carried out using the fluorescence filter. Special attention was paid to remnant 5-ALA positive tissue and these were resected when found. Tumors as well as remnant 5-ALA positive tissue were submitted to histological and immunohistochemical studies. Surgical videos and magnetic resonance imaging were analysed.
Results: All 36 tumors were found to be 5-ALA positive, but there was a difference in the glowing intensity. Inspection of the surgical field, dura and the bone flap was performed. Remnant 5-ALA positive tissue was identified invading the arachnoid plane or over the brain in 22% of the cases after total resection was assumed using the microscope’s regular white light. Positive 5-ALA tissue could be completely removed in all cases. Histological analysis of the remnant 5-ALA positive tissue that was further resected demonstrated the presence of tumor cells.
Conclusion: The use of 5-ALA for meningioma surgeries may improve the chances of total tumor resection. Inspection of the surgical field, dura and the bone flap using 5-ALA should be encouraged. An adaptation of the Simpson Grading System is proposed, so that results in meningioma resection using 5-ALA can be evaluated and compared between different centres.
