Indocyanine Green-Assisted Endoscopic Transorbital Excision of Lateral Orbital Apex Cavernous Hemangioma

Abstract

Orbital apex lesions posed operative difficulties to neurosurgeons and ophthalmologists due to limited surgical corridor and close vicinity to cranial nerves and arteries. Lateral orbital apex lesions were traditionally operated via the transcranial route by neurosurgeons. Recently, only a handful of reports have described the use of endoscope alone for excision of lateral orbital apex lesion. Our group, with both endoscopic skull base neurosurgeons and oculoplastic surgeons, has adopted the endoscopic transorbital approach for orbital apex lesions. We also used an indocyanine green (ICG) endoscope to aid identification and dissection of orbital apex cavernous hemangioma, which otherwise can be difficult to differentiate from surrounding intraconal recti muscles. Video 1 captured the first reported case of excision of lateral orbital apex cavernous hemangioma via endoscopic transorbital approach, using a zero-degree ICG endoscope. This was a 64-year-old Chinese woman who presented with right eye painless blurring of vision with visual acuity of 0.6 and right relative afferent pupillary defect. Fundoscopic examination showed absence of right optic disc swelling, and automated visual field testing confirmed a superior and infratemporal visual field defect in the right eye. On magnetic resonance imaging, there was a 1-cm oval mass that was hypointense on T1-weighted and hyperintense on T2-weighted images, with slow enhancement, suggestive of cavernous hemangioma. Optical coherence tomography of the retinal nerve fiber layer showed evidence of subtle right nerve fiber layer thinning. Right endoscopic transorbital excision of the tumor was performed with an ICG-assisted endoscope. Lateral skin crease incision was followed by crescent-shaped superolateral orbital rim removal. Superior and inferior orbital fissures were identified after stripping off the periorbita. The meningoorbital band was divided to release the orbital apex from the middle fossa dura. The greater wing of sphenoid bone was drilled with a 3-mm high-speed diamond burr under irrigation to create space for dissection. Injection of ICG resulted in delayed enhancement of the lesion at around 1 minute and 30 seconds, in contrast to rapid enhancement of surrounding recti muscles at around 30 seconds. Incision of periorbita was guided by ICG enhancement of lesion. The tumor was dissected from the lateral rectus and superior division of oculomotor nerve and was excised en bloc. The supraorbital rim was reconstructed with 2 miniplates. Pathology confirmed the diagnosis of cavernous hemangioma. Postoperatively, the patient had good recovery, with right eye visual acuity of 0.8 and resolution of the relative afferent pupillary defect.

Keywords: Endoscopic excision; Indocyanine green; Orbital apex cavernous hemangioma.