Ultrasound-based real-time neuronavigated fluorescence-guided surgery for high-grade gliomas: technical note and...

The extent of resection (EOR) plays a fundamental role in the prognosis of patients with high-grade gliomas (HGG). One of the main challenges in achieving a complete resection is the distinction between tumor and normal brain. Nowadays, several technologies are employed to obtain a higher tumor removal rate and respect the normal tissue in glioma surgery and in the last decades, fluorescein sodium (FS) and intraoperative ultrasound (IOUS) have been widely used. The aim of our technical note is to demonstrate how combining these two tools offers an ultrasound-based real-time neuronavigated fluorescence-guided surgery in order to optimize HGG removal.

Five patients (3 males, 2 females; mean age 55.2 years, range 36-68 years) undergoing craniotomies for removal of intraaxial lesions suggestive of high-grade gliomas on preoperative MRI were included in the study. Intraoperative navigated B-mode and CEUS associated with sodium fluorescein were used in all cases; white light appearance, IOUS, and fluorescence findings were recorded immediately after each surgery. Also, extent of resection was evaluated on postoperative Gd-enhanced MRI performed within 72 h.

All tumors effectively stained yellow with fluorescein sodium during the surgical procedure and four were well delineated by IOUS. IOUS was repeated frequently (average 2.6 time) to obtain an orientation of the gross residual tumor with respect to anatomical landmarks as the surgery proceeded. Tumor removal was completed under Yellow 560 filter.

In our technical report, we demonstrate that combining intraoperatively fluorescein sodium and IOUS improves the information and facilitates making decisions during the HGG surgery. Further experience gained in larger studies will help confirm these findings.