Answer to: "sodium fluorescein-guided resection under the YELLOW 560-nm surgical microscope filter in malignant brain tumor surgery-a feasibility study"

Dear Editor,
Regarding the article, “ Sodium fluorescein-guided resection under the YELLOW 560-nm surgical microscope filter in malignant brain tumor surgery — a feasibility study ” (April 2013, Volume 155, Issue 4, pp 693 – 69).

We read the article with great interest, as we believe fluorescence-guided surgery (FGS) is a real advance in neurosurgery, and have used it routinely since 2008. Unfortunately, we think this paper could introduce confusion and does not add new information to the field.

There are a number of very important caveats in the article. More important, the authors affirm that fluorescein (FL) was useful in many cases because the identification of the tumor mass and of the tumor margin was significantly better than under white light in many cases, but they do not include any objective standard to validate that conclusion.

It is accept- ed nowadays that the surgeon ’ s intraoperative assessment of the limit of the tumor is not an adequate measure [ 8 ]. This is the reason we use FGS, to begin with. To validate that FL is useful, they would need to correlate it with the pathology. A tool to identify tumor margin must be v alidated through its positive predictive value and negative predictive value and there is not a single biopsy in this paper.

The authors compare the method with 5-ALA FGS. 5-ALA use is supported by a very precise correla- tion between fluorescence and pathology, shown by Stummer [ 6 ], and confirmed later by all the groups who have tried it, including ours [ 1 – 3 , 5 ], with PPV of 100 % for solid tumor and 95 % for infiltration; this is the rationale behind the clinical success.

CITA DEL ARTÍCULO  Acta Neurochir (Wien). 2013 Jul;155(7):1319-20. doi: 10.1007/s00701-013-1752-7. Epub 2013 May 19.