Indocyanine Green (ICG) Use for Ophthalmic Artery Identification and Safe Optic Canal Opening during Expanded Endoscopic Endonasal Approaches

Introduction: Understanding the relationship of the ophthalmic artery (OA) origin from the internal carotid artery (ICA) as well as with the optic nerve (ON) is key to safe endoscopic endonasal approaches to the suprasellar region. Typically, the OA courses medial and inferior to the ON at its entry into the dura of the optic canal before beginning to course lateral to the ON. While this relationship is relatively consistent, noninvasive methods of confirmation are a valuable added layer of certainty. With improved endoscopic camera filters, indocyanine green (ICG) has proven useful for the assessment of nasoseptal flap (NSF) and ON perfusion as well as carotid artery localization. Here we describe the use of ICG for the reliable localization of the OA prior to opening of the dura of the optic canal during endonasal surgery.

Case 1: A 65-year-old female, with headaches and bilateral superior quadrantanopia, was found to have a large tuberculum meningioma ([Fig. 1A]). After NSF elevation, the extradural bone work was completed including removal of the tuberculum and proximal optic canal and medial opticocarotid recess (mOCR) exposure bilaterally. Ten mg of ICG within a 5-mL solution was injected intraoperatively followed by a saline flush to identify the OA course from the ICA and within the optic canal ([Fig. 2]). The optic canal dura was then opened at the superior and medial portion of the canal to prevent injury of the OA. A wide opening allowed visualization and early identification of the ONs during the remainder of tumor resection. The patient had a gross total resection ([Fig. 1B]) and did well postoperatively.

Case 2: A 60-year-old male, with known tuberculum meningioma, had progressive headaches and worsening bitemporal visual field loss ([Fig. 3A]). Similarly, after NSF harvest and extradural exposure of optic canals and mOCRs, 10 mg of ICG within 5 mL ICG was used to visualize the location of OA bilaterally prior to dural opening ([Fig. 4]). Dura of the proximal optic canal was again opened in the superomedial quadrant with preservation of the OA and early ON identification, facilitating a gross total resection ([Fig. 3B]). Additionally, separation of this dural leaflet along the proximal optic canal allowed more detailed inspection for tumor within the canal and also allowed safe dural cauterization.

Conclusion: Use of ICG to confirm the anatomic location of the OA bolsters the anatomic fund of knowledge of the endonasal skull base surgeon and allows more confidence in safe widening of the suprasellar corridor.

Publication History

Article published online:
07 February 2025

• References

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