Adjuncts for maximizing resection: 5-aminolevuinic acid.

The rationale for maximizing resection in surgery for malignant glioma has become broadly accepted in the neuro-oncology community, and technological adjuncts to facilitate achievement of this goal have incrementally assisted the neurosurgeon. One such adjunct of considerable interest today is 5-aminolevuinic acid (5-ALA)–induced protoporphyrin IX (PpIX) fluorescence. Preoperative oral administration of 5-ALA leads to preferential accumulation of the fluorophore PpIX within tumor cells, and under the violet-blue light illumination of the surgical field with an adapted operating microscope, tumor tissue exhibits visible red and near-infrared fluorescence. A German multi-institutional trial in 2006 demonstrated the potential utility of this technique,1 and although Food and Drug Administration approval in the United States is still pending, Investigational New Drug (IND)-supported experience in this country has furthered our understanding of this technology. This article presents the background for this methodology, the early clinical experience, its practical utility in intraoperative tumor boundary appreciation, its role near the end of resection, the development of quantitative fluorescence techniques, the experience in low-grade gliomas, and the implications of using this technique with respect to the objectives of surgery.