Comparison of Effectiveness, Feasibility, Indications, and Limitations of Different Intraoperative Dyes in Spinal Neuro-Oncologic Surgery. A Systematic Review

Background: Intramedullary spinal cord tumors (IMSCTs) are rare neoplasms and their management involves tumors resection in most cases. Regarding the surgical procedure, adequate identification of tumor boundaries is paramount to achieve an extensive tumor resection. Fluorescence image–guided surgery (FIGS) has become an increasing popular intraoperative technique used in spine neuro-oncology surgery. However, evidence is lacking of their usefulness and their safety in spinal tumors. Therefore, the aim of the present study is to give an update of the existing literature and systematically review all studies that focus on the most-used fluorophores (5 aminolevulinic acid [5-ALA], sodium fluorescein, and indocyanine green [ICG]) in IMSCTs. Methods: Using PubMed and Scopus, we performed a systematic review in accordance with the PRISMA protocol and screened all original studies involving humans treated for neurosurgical conditions and studies evaluating FIGS application in IMSCTs. Results: After the screening phase, 27 articles were found to be relevant. The literature results were grouped according to the used fluorophores, resulting in 3 groups: 5-ALA (10 studies); fluorescein (5 studies), and ICG (12 studies). Conclusions: In intramedullary tumor surgery, 5-ALA has shown its usefulness in identifying the tumor margins and in searching for residues because of its properties as a tumor-specific metabolic marker. Sodium fluorescein and ICG video angiography have shown promising application in ependymoma and hemangioblastomas surgery, respectively. However, the evolving role of fluorescent dyes in guiding surgical strategies in intramedullary spinal tumor has yet to be shown by randomized clinical trials.