Intraoperative Fluorescence With Second Window Indocyanine Green Enhances Visualization During Vestibular Schwannoma Surgery.

Abstract

To investigate the utility of the so-called "second window" of indocyanine green (ICG) as a near-infrared fluorescent dye for intraoperative visualization. Three patients who underwent surgical resection of vestibular schwannoma (two retrosigmoid and one middle fossa approach). Patients underwent intravenous infusion of ICG at a mean dose of 4.8 mg/kg at a mean of 15.3 hours before surgical incision. Once tumor dissection began, near-infrared fluorescence was used alongside conventional operative microscopy to visualize tumor tissue. Ability to distinguish tumor tissue from adjacent nerves. Intraoperative fluorescence allowed for enhanced visualization of the tumor-nerve plane in all patients. However, the effect varied among patients, and the effect faded with increasing surgical time. ICG, a well-tolerated cyanine dye, demonstrates late fluorescence hours after administration secondary to diffusion into tumor as well as normal tissues (the so-called "second window" of fluorescence). Its fluorescence in the near-infrared spectrum is a promising adjunct for enhancing visualization of tumor planes during vestibular schwannoma surgery.