1150 Improved Detection of 5-Aminolevulinic Acid-Induced Fluorescence in Gliomas Using A Novel Handheld Device

INTRODUCTION: Fluorescence-guided surgery (FGS) with 5-aminolevulinic acid (5-ALA) enables improved intraoperative visualization of gliomas and is performed using a microscope or exoscope (“scope(s)”) with blue wavelength light. However, quality of fluorescence is limited by the scope’s focal length, with the light source placed far away from the tissue of interest. We hypothesized that close-proximity fluorescence excitation using a novel handheld device (“NHD,” Nico Myriad fitted with blue light) held directly over tissue of interest would improve the quality of fluorescence compared to traditional scopes. METHODS: This was a prospective single arm study of 18 patients who underwent FGS for gliomas. During each case, three areas of tumor were inspected in vivo (within the surgical field) and ex vivo (removed from and visualized outside the field) using the scope alone or the scope and the NHD. Fluorescence intensity was scored as none, weak, or strong, and fluorescence character was scored as none, patchy, or uniform. These qualitative descriptions were converted into ordinal scores of 0, 1, and 2, respectively, and compared using Mann Whitney tests. Specimens were evaluated by a neuropathologist to verify presence of tumor cells. RESULTS: The NHD increased rates of positive fluorescence detection among pathologically confirmed tumor samples in vivo (NHD: 100% versus scope: 73%) and ex vivo (NHD: 94% vs. scope: 75%). The NHD improved fluorescence intensity and character in vivo (median intensity: NHD 1.67 vs. scope 1.00, p=0.03; character: NHD 1.33 vs. scope 1.00, p=0.02) and ex vivo (intensity: NHD 1.67 vs. scope 1.00, p=0.04; character: NHD 1.33 vs. scope 1.00, p<0.01). CONCLUSIONS: A handheld fluorescent device tangibly improved visualization of 5-ALA-induced glioma fluorescence compared to traditional operating scopes.