Neuroendoscopic Cylinder Surgery and 5-Aminolevulinic Acid Photodynamic Diagnosis of Deep-Seated Intracranial Lesions

Background Microscopic detection of intracranial brain tumors with 5-aminolevulinic acid (5-ALA) has proven extremely useful, and reports the use of 5-ALA have recently increased. However, few reports have described 5-ALA photodynamic diagnosis (PDD) using a neuroendoscope. We performed neuroendoscopic 5-ALA PDD for various brain lesions and present a procedure using only a neuroendoscope. Methods We describe the diagnosis of 20 intracranial brain lesion cases with a 5-ALA–guided fluorescence endoscope. A light-emitting diode that emitted either white light or 400- to 410-nm violet light was attached to a neuroendoscope. We performed cylinder surgery with a transparent sheath under observation with a rigid neuroendoscope. Results Neuroendoscopic biopsies were performed in 11 patients, and resections were performed in 9 patients. All lesions were observed with a neuroendoscope under sequential white light and violet light. We confirmed the presence of a red fluorescent lesion under violet light in 15 patients, including 4 of 5 glioblastoma cases (80%); 1 of 2 anaplastic astrocytoma cases (50%); 4 of 5 diffuse large B cell lymphoma cases (80%); 2 of 2 metastatic brain tumors; 1 of 1 case each of diffuse astrocytoma, pilocytic astrocytoma, inflammatory change, and germinoma (100%); and no cases of anaplastic ependymoma or cysticercosis. Pretargeted lesions were accurately harvested from all biopsy specimens. Gross total resection was achieved in 5 of 9 patients using a resection procedure. Conclusions Our described method offers a promising technique for achieving precise brain tumor biopsies and safe resection.