Fenestration surgery, or in other words, the making of openings in canals, was used to treat otosclerosis during the 1940's, before the invention of the stapes operation for otosclerosis. There are still many patients who have fenestrations. Nearly all of these patients have Tullio's, and all have pressure sensitivity, such as elicited by a Valsalva maneuver.
In fenestration surgery for otosclerosis, an opening was made in the lateral semicircular canal through the mastoid. This image, from Niyazov et al (2000) shows an axial CT scan of an individual with fenestration.
The movie shows the results of Valsalva in a patient with a fenestration: fenestration small. There is a horizontal nystagmus induced by straining.