gms | German Medical Science

Objective: Spinal cord and brain stem lesions require a judicious approach with an optimized trajectory due to a clustering of functions on their surfaces. Intraoperative mapping helps locate function. To confidently locate such lesions, neuronavigation alone lack the desired accuracy and is of limited use in the spinal cord.Our aim was to evaluate the fluoresceins clinical value for initial delineation of such critically located lesions.

Methods: We evaluated fluorescein-guidance in the surgical resection of lesions with blood-brain-barrier disruption demonstrating contrast-enhancement in magnet resonance imaging in the spinal cord and in the brain stem in three different patients. Two patients harbored each a diffuse cervical and thoracic spinal cord lesion. Another patient suffered metastatic lesions in the brain stem and at the floor of the 4th ventricle. Low-dose fluorescein (4 mg/kg body weight) was applied after anesthesia induction and visualized using the Zeiss Pentero 900 Yellow560 filter.

Results: Fluorescein was helpful for locating lesions and for defining the best possible trajectory. During resection, however, we found unspecific propagation of fluorescein within the brain stem up to 6mm within 3 hours after application. As these lesions were otherwise distinguishable from surrounding tissue, monitoring resection was not an issue.

Conclusion: Fluorescein-guidance is a feasible tool for defining surgical entry zones when aiming for surgical removal of spinal cord and brain stem lesions. Unselective fluorescein extravasation cautions against using such methodology for monitoring completeness of resection. Providing the right timing, a window of pseudoselectivity could increase fluoresceins clinical value in these cases.

Figure 1 [Fig. 1], Figure 2 [Fig. 2]