Feasibility of endoscopic treatment of middle ear myoclonus: a cadaveric study

Abstract

Stapedius and tensor tympani tenotomy is a relatively simple surgical procedure commonly performed to control pulsatile tinnitus due to middle ear myoclonus and for several other indications. We designed a cadaveric study to assess the feasibility of an entirely endoscopic approach to stapedius and tensor tympani tenotomy. We performed this endoscopic ear surgery in 10 cadaveric temporal bones and summarized our experience. Endoscopic stapedius and tensor tympani section is a new, minimally invasive treatment option for middle ear myoclonus that should be considered as the first line surgical approach in patients who fail medical therapy. The use of an endoscopic approach allows for easier access and vastly superior visualization of the relevant anatomy, which in turn allows the surgeon to minimize tissue dissection. The entire operation, including raising the tympanomeatal flap and tendon section, can be safely completed under visualization with a rigid endoscope.

Figure 1

For endoscopic section of the stapedius and tensor tympani, we used the Hopkins rod rigid endoscopes, 2.7 mm diameter, zero and 30° angled, length 14 cm. These endoscopes are commonly used in pediatric endoscopic sinus surgery.

Figure 2

Wide view of the middle ear cavity with clearly visible stapedius and tensor tympani tendons, using a 4.0 mm, 30° rigid endoscope. The tympanomeatal flap is elevated to the level of the malleus but is not separated from the malleus. Single black arrow: stapedius tendon; double white arrow: tensor tympani tendon arises from the cochleariform process and attaches to the underside of the malleus neck.

Figure 3

The best instrument to sever the stapedius tendon is a straight sharp instrument such as a Bellucci microscissors.

Figure 4

The cut ends of the stapedius tendon have memory. Here, the cut ends are deflected away from each other with a pick to create a gap and prevent reanastomosis which could potentially lead to recurrence of symptoms.

Figure 5

In this specimen with a narrow external auditory canal and significant anterior bony bulge, a smaller, 1.9 mm diameter, 30° endoscope was used to raise the tympanomeatal flap and visualize the tensor tympani tendon.

Figure 6

The best instrument to sever the tensor tympani tendon is a curved sharp instrument such as a joint knife used in stapedotomy.