Intuitive intraoperative ultrasound guidance using the Sonic Flashlight: a novel ultrasound display system

The Sonic Flashlight (SF) is a new handheld ultrasound (US) display device being developed at our institution. It replaces the standard monitor on a conventional ultrasound (CUS) system with a miniature monitor and half-silvered mirror to reflect real-time US images into the body. With the SF, the imaged body part appears translucent, with the US image appearing to float below the surface of the anatomy, exactly where it is being scanned. The SF merges the patient, US image, instrument, and operator's hands into the same field of view, allowing the user to operate directly on the US image using normal hand-eye coordination. In contrast, CUS procedures result in displaced hand-eye coordination when the operator looks away from the patient to view the CUS monitor. Intraoperatively, the SF may make localizing and accessing tumors, foreign bodies, hematomas, vascular malformations, and ventricles easier and more accurate, especially for those without extensive CUS training.

In this cadaver study, the SF was used to visualize the brain and guide a needle into an implanted simulated tumor. The needle was inserted both in the US plane and outside of the US plane.

Sonic Flashlight fifth generation research prototype.

The needle was easily and intuitively visualized and guided into the lesion, both within and outside of the US plane. By having the US image appear directly beneath the brain surface, the surgeon can easily and quickly guide the needle or surgical instrument to the lesion. The operator's eyes never have to leave the surgical field, as they do with CUS technology. The impact of this device on neurosurgical procedures could be significant. The ease of use, intuitive function, and small instrument size allow the surgeon to quickly localize lesions, confirm surgical positioning, and assess postoperative results.