[Intraoperative fluorescence diagnostics upon recurrent operations for brain gliomas]

The method of fluorescent diagnosis (FD) using 5-ALA has been widely employed in surgery of primary intracerebral tumors over the last years. The issue of FD application in surgery of gliomas with continued growth has remained less studied.

To investigate the efficacy of using FD with 5-ALA and laser spectral analysis in surgery of brain gliomas with continued growth.

19 patients with Grade II-IV (WHO) gliomas with continued growth of different localization were studied. All tumors localized supratentorially. 5-Aminolevulinic acid hydrochloride "Alasens" (SSC "NIOPIK", Moscow, Russia) was used in the study. The equipment used during surgery included an operating microscope with an attachment for fluorescent navigation. Apart from expert qualitative assessment of a fluorescence extent, computer analysis of the fluorescence and light scattering (diffuse reflection) spectra was performed on a LESA-01-BIOSPEK spectrum analyzer (Russia).

Detectable fluorescence was obtained in all the cases. PP IX fluorescence indices from 9.05 to 53.97 (the study was conducted in 12 cases) were determined by quantitative analysis of the spectrograms. The analysis of light scattering revealed its inverse relationship with respect to the fluorescence index. High sensitivity of the method in surgery of gliomas with continued growth requires clarification of method specificity because non-specific accumulation of PP IX in the area of post-radiation necrosis may occur in these patients.

The FD method can be used for intraoperative demarcation of tumor resection boundaries in surgery of cerebral gliomas with continued growth. However, it is necessary to be critical of the high sensitivity of the method in patients with postradiation pathomorphism due to possible non-specific accumulation of PP IX in tissues. A light scattering study may provide additional information about the structure of tissues in the surgical wound.