Microvascular Cortical Dynamics in Minimal Invasive Deep-Seated Brain Tumour Surgery

Abstract

Background: The tubular retractor-assisted minimally invasive parafascicular approach (trMIPS) is a transsulcal approach to deep-seated brain tumours. It is a safe surgical approach but its impact on the microvascular dynamics of the retracted cortex and its clinical implications are unknown.

Methods: This was a single-centre prospective study including patients with deep-seated brain tumours operated on with a trMIPS (BrainPath Nico System^©). All patients underwent pre- and post-cannulation indocyanine green study using a FLOW 800 module in a KINEVO Zeiss^© microscope. Speed, delay, time-to-peak (TtP) rise-in-time and cerebral blood flow index (CBFI) metrics were assessed.

Results: Thirty-five patients were included, with 144 regions-of-interest (ROIs) selected. The majority of patients were diagnosed with glioblastoma (51.43%), and 37.14% of patients had a preoperative focal neurological deficit (FND) at presentation. A ROI-based analysis concluded that an increase in speed and CBFI was related with a worse neurological outcome when comparing the pre- and post-brain cannulation assessments (speed: deterioration = 43.12 ± 80.60% versus stable = -14.51 ± 57.80% versus improvement = 6.93 ± 31.33%, p < 0.0001; CBFI: deterioration = 50.40 ± 88.17% versus stable = -2.70 ± 67.54% versus improvement = -38.98 ± 26.17%, p = 0.0005). These findings were reproducible in a combined-ROI per patient analysis and confirmed after adjustment for confounding.

Conclusion: Microvascular flow dynamics impact trMIPS outcomes as an increase in the speed and CBFI after decannulation was related with worse neurological outcome.

Keywords: deep-seated lesions; microvascularization; minimal invasive parafascicular surgery; neuro-oncology; transsulcal approach; tubular retractor.

Figure 1

Indocyanine green quantitative assessment with Zeiss Flow 800^© module using Zeiss Kinevo 900^© Microscope—(A–D) show the pre-brain cannulation and post-brain decannulation intensity (A,B) and speed (C,D)—pre-cannulation on the left and post-cannulation on the right. (E,F) show the final diagram that assesses the delay, speed, time to peak and rise time in the selected regions-of-interest before (E) and after (F) brain cannulation.

Figure 2

Region-of-Interest Based Analysis—(Top left): Pre brain cannulation quantitative flow metrics and presence of preoperative focal neurological deficit. (Top right): Post brain decannulation quantitative flow metrics and the postoperative overall neurology. (Bottom left): Pre brain cannulation—post brain decannulation ICG flow metric percentage changes and overall neurology. (Bottom right): Receiver Operating Characteristic Curve Analysis using the flow metrics that showed statistical significance during the uni and multivariate analysis.

Figure 3

Combined Region-of-Interest per Patient Analysis—(Top left): Pre brain cannulation quantitative flow metrics and presence of preoperative focal neurological deficit. (Top right): Post brain decannulation quantitative flow metrics and the postoperative overall neurology. (Bottom left): Pre brain cannulation—post brain decannulation ICG flow metric percentage changes and overall neurology. (Bottom right): Receiver Operating Characteristic Curve Analysis using the flow metrics that showed statistical significance during the uni and multivariate analysis.