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

Objective: To investigate the utility of the so-called second window of indocyanine green (ICG) as a near-infrared fluorescent dye for intraoperative visualization. Patients: Three patients who underwent surgical resection of vestibular schwannoma (two retrosigmoid and one middle fossa approach). Intervention(s): 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. Main Outcome Measure(s): Ability to distinguish tumor tissue from adjacent nerves. Results: 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. Conclusions: 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.

Automated summary

This study investigated the utility of ICG as a near-infrared fluorescent dye for intraoperative visualization in vestibular schwannoma surgery. The results showed that ICG fluorescence enhanced visualization of the tumor-nerve plane, but the effect faded with increasing surgical time.