Resection in glioblastoma: maximal or safe

Dear Editor
We read the recently published article by Pastor et al. [ 8 ]in Acta Neurochirurgica : “ Role of intraoperative neurophysio- logical monitoring during fluorescence-guided resection surgery ”.

While we fundamentally agree that intraoperative neuro- physiological monitoring (IONM) is useful to avoid neuro- logical deficit, the data shown do not support the conclusion that is also helpful to maximise resection.

In this regard, we found some issues in the paper that should be commented on: Only patients with Karnofsky performance score (KPS) over 70 % were included, so this was a favourably selected patient group, as patients with relevant neurological deficits were excluded.

This is uncommon for series dealing with eloquent area tumours. The authors concluded that monitoring in anaesthetised patients is safe and more comfortable for the patient and team than awake surgery. It is true that this is more comfortable, but the study is underpowered for any comparison, and implying that monitoring in anaesthetised patients is as safe as awake surgery could be misleading.

Nothing is told about speech monitoring, and they did not include any “ cortical ” tumour near speech areas. In their “ semi-oval ” area cases, there was one patient with aphasia at 3 months. It is surprising they did not cite the work by Schucht et al. [ 5 ], dealing with the same issue and including awake cases, a comparison of monitoring methods and results would have been interesting.

CITATION  Acta Neurochir (Wien). 2014 Feb;156(2):325-6. doi: 10.1007/s00701-013-1967-7. Epub 2013 Dec 15