ALA-induced fluorescence image guided surgery of meningiomas: A meta-analyses

- Surgical excision of meningiomas in certain situations remains a challenging task and associated with high recurrences and significant morbidity.
- 95% of meningiomas regardless of histological grade fluoresced during surgery (95%CI 91.8-87.7%).
- No significant correlation existed between fluorescence and histological grade (p > 0.05).
- Gross total resection (GTR), Simpson grade 1 & 2, was achieved in 94.5% of all meningiomas using ALA-FIGS (90.9% to 98.2%).
- Using ALA-FIGS, none of WHO grade I recurred after GTR (0/148) compared to six out of 27 (22.2%) of WHO grade II & III meningiomas after GTR.

BackgroundThough meningiomas are often benign and well circumscribed in nature, many are associated with recurrences and poor outcome because of their attachment to neurovascular nearby structures or invasion of adjacent venous sinuses or bone, forcing incomplete excision and deployment of further salvage therapy. Recently, ALA-FIGS has been reported as an aid to increase the chances of complete resection and minimizing collateral damage.MethodsCritical review and meta-analyses of the literature published to date. All studies reporting ALA-FIGS in meningiomas were critically reviewed. Nineteen studies fulfilled the inclusion criteria with a total of 222 patients, of which 206 were included in the meta-analyses.ResultsALA-FIGS was highly specific, and highly sensitive (95%, range 91.8-97.7%). There was no correlation between WHO grading (WHO grade I versus WHO grades II & III) and fluorescence (odds ratio 1.2, p > 0.05). ALA-FIGS altered the surgical plan intraoperatively in 75% of high-grade and 19% of low-grade meningiomas, improving the extent of surgical excision. ALA-FIGS was also highly sensitive and specific in differentiating hypertrophy and tumor invasion of adjacent dura and bone.ConclusionsALA-FIGS in meningiomas is very selective, highly sensitive, and improves the extent of surgical resection in meningiomas. Long-term outcome of these tumors in the future should be categorized into those with and without residual fluorescent tissue. A new surgical resection grading system based on ALA-FIGS is proposed.