Fluorescein-aided neurosurgery

Neurosurgery made enormous advances over the last century. Moving from a meticulous anatomical knowledge of the cerebral structures and passing through the “microscope revolution” we arrived in the modern neuronavigation era in which we can render and correlate real-time the preoperative imaging to the patient. Real life, though, is way different from simulation and technological promises. In fact, some tumours are still almost undistinguishable from the brain in normal vision and our individual estimate of vessel patency may be proved way wrong at the ischemic post operative imaging. Sometimes, even with all the best resources, we are blindly performing life-saving procedures. The development of fluorescent intra-operative tracers tried to address these issues. This PhD thesis is, basically, the synthesis of three years of personal clinical experience on the experimental use of intra-operative Fluorescein in Neurosurgery. Briefly, I will describe the optical and pharmaceutical properties of Fluorescein and explain how I assembled a low-cost fluorescence detection system. Then I will go through all the fields of Neurosurgery in which I applied this technology. Firstly, I will report the preliminary results of an ongoing Clinical Trial on the use of Fluorescein as an intra-operative contrast enhancer of the borders of high grade glioma tumours. Then, the potential advantages of fluorescein use in vascular neurosurgery will be discussed. In particular the use of fluorescein for the evaluation of the exclusion of intra-cerebral aneurysms will be illustrated by means of an explicative case. Similarly, I will report the usefulness of intra-operative fluorescence detection in a case of intra-cerebral cavernoma. Lastly, I will describe the experience of fluorescein staining in the field of Hereditary hemorrhagic telangiectasia and explain the potential advantages of this technique in arteriovenous malformations. Eventually, I will describe the usefulness of dedicated endoscopic filters for fluorescein detection in trans-nasal skull base procedures. The rationale and preliminary results of the use of fluorescein as an intra-operative contrast medium in pituitary adenoma surgery will be presented. CSF leak detection and pedicled flaps' perfusion evaluation techniques will be also described in detail.