Preliminary Single-Center Experience with the Use of ICG in Endoscopic Skull Base Surgery: New Findings and Proposed Indications

Background Endoscopic ICG (e-ICG) is a new technology amenable to skull base surgery. Few reports have presented its benefits in visualization of vascular structures, harvesting the nasoseptal flap and during resection of different skull base pathologies.

Objective To assess the benefit of the ICG in endoscopic skull base surgery while gathering information from previous studies and combining with our experience to provide practical indications for the use of this technology.

Methods In this prospective study, eight patients enrolled including pituitary adenomas (n = 5), dorsum sellae meningiomas (n = 2), and chordoma (n = 1). One vial of ICG is used for each patient. One shot dose (25 mg) or two divided doses (12.5 mg each) are given to each patient in different stages of the operation. For the e-ICG we used a 0° rod-lens endoscope (5.8 mm in diameter,19 cm in length) and Image 1 H3-Z FI three-chip ICG Full HD Camera Head (KARL STORZ). Timing of the carotid fluorescence and the sequence of the structures visualized were reported.

Results Structures visualized by the e-ICG can be categorized into vascular structures, the pituitary gland, and tumors. The aim of e-ICG should be planned before surgery and designed individually for each case in correlation with the radiology of the patients. In the corridor stage, assessing the flaps, localizing the internal carotid artery to plan the extent of sellar drilling or avoid its injury particularly for tumors with close proximity to the vessel. e-ICG helped identify and then cauterize the meningeal feeders of the dural attachment of meningiomas. In addition, it helps identify the pituitary gland aiding to follow a more precise plane for extracapsular dissection, thus avoiding injury of the pituitary gland in adenomas. During the dissection phase, the persistence of the fluorescence guided the dissection toward tumor that maybe hidden by bone, especially in chordoma; following the resection, e-ICG helped confirm the integrity of perforating vessels, identify pituitary gland and its stalk and to identify sources of bleeding.

Conclusion E-ICG is a useful tool in skull base surgeries. In addition to the few previous experiences, findings such as staining of chordomas and meningiomas have the potential to improve the extent of resection and better Simpson grading, respectively.