August 17, 2016
This video describes performance of a subtemporal craniotomy for repair of the superior semicircular canal dehiscence. This is a 32-year-old female who presented with intractable vertigo and right-sided hearing loss. CT of the skull base and more specifically the temporal bone, revealed semicircular canal dehiscence at the tip of the arrow on the coronal and sagittal images. A lumbar drain was installed. Patient underwent a right-sided temporal craniotomy. In this case, a C-shaped incision was used, although a linear or a horseshoe incision is also acceptable. Following reflection of the scalp and the temporalis muscle, a burr hole was placed at the root of the zygoma. A temporal craniotomy was elevated. The lower edge of the craniotomy was as close to the level of the middle fossa as possible. About 40 cc of CSF was withdrawn from the lumbar drain. The overhanging ledge of bone over the inferior edge of the craniotomy was drilled away. The mastoid air cells were adequately waxed, and the dura was mobilized away from the middle fossa floor. The point of dehiscence over the tegmen was identified. Here, you can see the point of dehiscence with some herniation of the dura. Here is a clear identification of the semicircular canal dehiscence. There are various ways of repairing this dehiscence, including the use of bone paste or bone wax. We prefer to use a piece of bone from the craniotomy bone flap. This piece of bone is used to create a barrier between the dura and the point of dehiscence. In addition, fibrin glue is used to reinforce the reconstruction. For closure, the mastoid air cells are re-waxed. and the bone flap is replaced. And the rest of the closure performed in standard fashion. Thank you.
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