Some of the tiniest structures that can be operated on in the human body are in the ear. For example, the eardrum is 0.1 mm thick, and the middle ear bones (ossicles) are the smallest bones in the body.
Indeed, these bones are so small that multiple sets of these ossicles could fit on a dime.
Until relatively recently, ear surgeons have relied exclusively on a specialized microscope to view the ear. Microscopes provide 3D views of structures. However, they are unable to provide a view that is larger than the lens and the cylinder of light that illuminates the subject (see endoscope vs. microscope illustration below).
Because the microscope can view only a cylinder of light, it cannot always see all off the nooks and crannies of the ear.
Microscopes are limited to a single “column” view. The view of an endoscope is markedly wider.
Endoscopic ear surgery is an emerging surgical technique for performing certain types of ear procedures. Endoscopes have a much wider or panoramic view than the traditionally used microscope. Endoscopes are also very long and thin. Thus, they can be maneuvered around small ear structures to provide better views than with a microscope.
Indeed, with angled lenses, the endoscope can even see around corners!
Because of these advantages, endoscopes can enable certain ear procedures to be done entirely through the canal (i.e. transcanal approach). Before endoscopes, ear procedures often required combination transcanal and behind-the-ear incisions. Endoscopes have made it possible to complete some ear surgeries entirely transcanal. This speeds up healing time and decreases pain and risk to the patient.
Microscopes and endoscopes have their roles in ear surgery. A key disadvantage of endoscopes is the monocular (single lens) view. To gain a 3D sense of the operating field, the surgeon must move the endoscope around to get a sense of depth perception.
In contrast, microscopes have binocular, stereo vision. Endoscopes also have other disadvantages. Because one hand must support the scope, there is only one hand that can hold the operating instrument. Microscopes also allow for two handed surgery.
Despite these disadvantages, multiple research studies show endoscopic surgery to be as safe as surgery with a microscope. Thus, many ear surgeries use the endoscope as an adjunct to the microscope. This is called “endoscopically assisted surgery.”
Common ear procedures that use endoscopy are middle ear growths (e.g. cholesteatoma), repairing the middle ear bones, and patching holes in eardrums. Dr. Ruffin uses endoscopic ear surgery in his practice.