Page 82 - Fluorescence-guided cancer surgery

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Chapter 5
light, was technically possible. Possibly tumor resection under continuous NIR uorescence guidance, instead of only checking for tumor remnants at the end of surgery may be the best way to use NIR uorescence guidance in pituitary surgery. From the current study, no optimal interval between ICG administration and peak uorescence signal can be recommended. For all measurements, an interval of 45 seconds was taken to obtain and analyse uorescent signal. In our experience, the uorescent signal and contrast ratio stayed optimal for 1-2 minutes in all patients, and than slowly decreased over time. Timing of ICG administration warrants further systematic study.
For NIR uorescence imaging during pituitary surgery a special endoscope is needed equipped with an excitation light source to excite uorophores, and a detection device to capture emitted uorescence from the exited uorophores. The dimensions and functionality of this scope are otherwise identical with the regular HD Storz endoscope. ICG was readily available at the pharmacy. The technique of imaging was not complicated and was not associated with any sided e ects. In one patient cavernous sinus bleeding prevented assessment of the uorescence. As long as venous bleeding is well controlled, NIR uorescence imaging can be used to remove adenoma tissue from the cavernous sinus. NIR uorescence imaging during endoscopic pituitary surgery is easily implemented in current daily practice. As ICG can be visualized under specially equipped surgical microscopes, which are already clinically available, NIR uorescence imaging is also possible in microscopic transsphenoidal procedures.
Although transsphenoidal surgery is an established, relatively safe procedure, iatrogenic pituitary dysfunction is still a considerable drawback. A postoperative rate of hypopituitarism of 22% is reported4. Diabetes insipidus (DI) and pituitary insu ciency are commonly reported following transsphenoidal surgery. DI can be divided in temporary DI (incidence if 10 - 60%) and the uncommon permanent DI (0.5 – 15%)4. The cause of DI has been ascribed to stalk manipulation during surgery, and is more common after resection of microadenomas. Postoperative pituitary insu ciency is reported in 1-10% of patients; however outliers of 27% are documented4. In a recent structured review and meta-analysis of the available literature, Roelfsema et al. reported the onset of new, surgery-related pituitary insu ciency in 6.9 ± 1.8% of patients treated for prolactinoma, 6.7 +/- 1.6 for acromegaly, 12.5 +/- 4.6 % for NFA and 25.4 +/- 3.6 % for Cushing’s disease5.