Guidance of retrobulbar injection with real-time tomographic reflection.

OBJECTIVE Retrobulbar and peribulbar injections are common ophthalmologic procedures used to deliver anesthetics and other medications for ophthalmic therapy and surgery. These injections, typically performed without any type of guidance, can lead to complications that are rare but visually devastating. The needle may penetrate the optic nerve, perforate the globe, or disperse toxic quantities of drugs intraocularly, causing major visual loss. Sonographic guidance may increase the accuracy of the needle placement, thereby decreasing the incidence of complications. However, difficulties arise in coordinating the relative location of the image, the needle, and the patient. Real-time tomographic reflection is a new method for in situ visualization of sonographic images, permitting direct hand-eye coordination to guide invasive instruments beneath the surface of the skin. METHOD In this preliminary study, real-time tomographic reflection was used to visualize the eye and surrounding anatomic structures in a cadaver during a simulated retrobulbar injection. RESULT The needle tip was easily followed as it was advanced into the retrobulbar space. CONCLUSIONS The images presented in this preliminary study show the use of real-time tomographic reflection to visualize insertion of an invasive instrument into the human body.