Silastic sheeting in the middle ear.

We examined a 45-year-old male patient who 9 months earlier had undergone a tympanoplasty and mastoidectomy for removal of a cholesteatoma from the middle ear and mastoid on the left side. Otoscopy revealed that a piece of Silastic sheeting was present behind an intact tympanic membrane graft (figure). The malleus and incus bones had been sacrificed during the surgery, and the stapes was missing because of the disease. The eardrum had been reconstructed with temporal fascia in an overlay fashion. A tongue of fascia was slipped behind the posterior canal wall to prevent lateralization of the graft. The Silastic sheeting was placed between the graft and the promontory to create a middle ear space. The middle ear mucosa was missing in the area of the promontory and diseased around the area of the eustachian tube and in the hypotympanum.

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Placement of Silastic sheeting helps guide the middle-ear mucosa to heal and line the areas where it was missing because of disease or surgery, and it helps prevent the formation a fadhesions between the graft and the promontory. As a result, it creates a middle ear space and ultimately leads to a better functional outcome. Revision surgery is typically undertaken 1 year later to check for residual disease and to reconstruct the ossicular mechanism. At this time, the Silastic sheeting is removed from the middle ear and the ossicular chain is reconstructed with tragal cartilage and either a partial or total ossicular replacement prosthesis, depending on the status of the stapes. Better hearing is achieved when the stapes is present.

Some patients are able to hear through Silastic sheeting, and they may not require a second-stage procedure unless residual disease is suspected. The reasons for staging include mucosal disease, a fixed stapes, and possible residual cholesteatoma.

From the House Ear Clinic, Los Angeles, and the Keck School of Medicine, University of Southern California, Los Angeles.