Intraoperative cerebral blood flow monitoring in neurosurgery: A review of contemporary technologies and emerging perspectives.

Intraoperative monitoring of cerebral blood flow (CBF) has become an invaluable adjunct to vascular and oncological neurosurgery, reducing the risk of postoperative morbidity and mortality. Several technologies have been developed during the last two decades, including laser-based techniques, videomicroscopy, intraoperative MRI, indocyanine green angiography, and thermography. Although these technologies have been thoroughly studied and clinically applied outside the operative room, current practice lacks an optimal technology that perfectly fits the workflow within the neurosurgical operative room. The different available technologies have specific strengths but suffer several drawbacks, mainly including limited spatial and/or temporal resolution. An optimal CBF monitoring technology should meet particular criteria for intraoperative use: excellent spatial and temporal resolution, integration in the operative workflow, real-time quantitative monitoring, ease of use, and non-contact technique. We here review the main contemporary technologies for intraoperative CBF monitoring and their current and potential future applications in neurosurgery.

Optimization of high-grade glioma resection using 5-ALA fluorescence-guided surgery: A literature review and practical recommendations from the neuro-oncology club of the French society of neurosurgery.

BACKGROUND: When feasible, the surgical resection is the standard first step of the management of high-grade gliomas. 5-ALA fluorescence-guided-surgery (5-ALA-FGS) was developed to ease the intra-operative delineation of tumor borders in order to maximize the extent of resection. METHODS: A Medline electronic database search was conducted. English language studies from January 1998 until July 2018 were included, following the PRISMA guidelines. RESULTS: 5-ALA can be considered as a specific tool for the detection of tumor remnant but has a weaker sensibility (level 2). 5-ALA-FGS is associated with a significant increase in the rate of gross total resection reaching more than 90% in some series (level 1). Consistently, 5-ALAFGS improves progression-free survival (level 1). However, the gain in overall survival is more debated. The use of 5-ALA-FGS in eloquent areas is feasible but requires simultaneous intraoperative electrophysiologic functional brain monitoring to precisely locate and preserve eloquent areas (level 2). 5-ALA is usable during the first resection of a glioma but also at recurrence (level 2). From a practical standpoint, 5-ALA is orally administered 3 hours before the induction of anesthesia, the recommended dose being 20 mg/kg. Intra-operatively, the procedure is performed as usually with a central debulking and a peripheral dissection during which the surgeon switches from white to blue light. Provided that some precautions are observed, the technique does not expose the patient to particular complications. CONCLUSION: Although 5-ALA-FGS contributes to improve gliomas management, there are still some limitations. Future methods will be developed to improve the sensibility of 5-ALA-FGS.

Is fluorescence-guided surgery with 5-ala in eloquent areas for malignant gliomas a reasonable and useful technique?

INTRODUCTION: High-grade gliomas surgery in eloquent areas must achieve two pivotal aims: oncological efficacy and preservation of unimpaired neurological functions or improvement of impaired neurological functions. Here, we evaluated the safety and the usefulness of 5-ALA fluorescence-guided surgery in eloquent areas. MATERIAL AND METHODS: Single center, retrospective and consecutive series of adult patients operated on for a supratentorial glioblastoma between November 2012 and November 2015. RESULTS: Fifty-one patients with a glioblastoma located within an eloquent area were included: 24 patients operated on with 5-ALA (5-ALA group), and 27 patients operated on under white light (control group). Preoperative motor and language deficits were similar in the 5-ALA group (50%, 37.5%) as in the control group (59.3%, 55.6%) (P=0.510; P=0.200). Three-month postoperative motor and language deficits rates were similar in the 5-ALA group (12.5%, 12.5%) as in the control group (29.6%, 14.8%) (P=0.180; P=0.990). The extent of resection did not significantly vary between groups (P=0.280). The overall survival did not significantly vary between groups (P=0.080) but the progression-free survival was significantly higher in the 5-ALA group than in the control group (P=0.020). The 12-month progression-free survival was significantly higher in 5-ALA group (60%) than in control group (21%; P=0.006). In multivariate analysis, the 5-ALA was an independent prognostic factor associated with progression-free survival (P=0.030). CONCLUSION: 5-ALA fluorescence-guided surgery for glioblastoma located in eloquent areas is effective to improve progression-free survival. To preserve functional outcomes, it requires the routine use of intraoperative functional mapping to respect functional boundaries.