Maintaining the Middle Ear Space

Once the reconstruction is complete, one must take the necessary steps to maintain a good reconstruction. The first step is the maintenance of an air-containing middle ear space during the immediate healing period. There are many options for maintaining this space. By far the most popular in the United States is the use of Gelfoam or Gelfilm.

Gelfoam is a cellulose-based foam that is thought to be enzymatically degraded in 50 to 60 days by the middle ear. Major benefits are its easy insertion into the middle ear, low cost, ability to be cut into any size, and relative stability over the first 3 to 4 weeks postreconstruction. The main drawback of Gelfoam is risk of fibrosis. Animal research utilizing multiple models has shown a propensity of Gelfoam to act as scaffolding for fibroblasts and adhesions when the mucosa is disrupted in the middle ear.26 28

Gelfilm, like Gelfoam, is also a cellulose-based product. Constructed into sheets, this very thin film allows coverage in areas of denuded mucosa to prevent fibrosis and maintain an adequate middle ear space. Unlike Gelfoam, animal studies using Gelfilm fail to show any propensity for fibrosis.26 Unfortunately, this product conforms very poorly to the middle ear space and is not useful as a mechanism to maintain the entire space postoperatively.

Because of the shortcomings of both Gelfilm and Gelfoam, other products have recently been investigated. Currently, the most promising of these is sodium hyaluronate. Studies in both the orthopedic and ophthalmologic literature reveal this product to be a promoter of healing and, because of its natural occurrence in the body, to be well tolerated. In its esterified form, this chemical has been constructed into sheets and into an easily molded powder very similar to Avitene (CR Bard Inc., Murray Hill, NJ) in consistency. The hyaluronate products currently on the market are Epifilm (Medtronic Xomed Surgical Products Inc., Jacksonville, FL), Epidisc (Medtronic Xomed Surgical Products Inc.), Merogel (Medtronic Xomed Surgical Products Inc.), and SepraPak (Gyrus ENT Division). Epifilm and Merogel have been examined in animal models29 and have been advertised to have results superior to those of Gelfoam. Particularly appealing is the fact that these products degrade more rapidly than Gelfoam, thus minimizing fibrosis. The principal drawback of hyaluronate is its inability to conform to the middle ear space, and the increased cost compared to Gelfoam or Gelfilm.

Another product that bears mention, which has been utilized for years to maintain the middle ear cleft, is Silastic sheeting. This biologically inert material can be placed into the middle ear to maintain the needed space until an adequate ossi-culoplasty can be performed at a later date. The main drawback of Silastic sheeting is the lack of degradation of the product when placed into the ear. Because of this, the Silastic sheeting must be removed from the middle ear space at some point. Given the trend to avoid second-stage surgeries, use of this material has been increasingly limited.

Our current technique for the maintenance of the middle ear space is the sparing use of Gelfoam. Given the exceptional stability of the hybrid prosthesis, we typically use no additional material to support the middle ear space when utilizing this prosthesis. We utilize Gelfilm to cover areas of mucosa that have been totally denuded. As the sodium hyaluronate products continue to improve their middle ear conformability, we expect to eliminate our use of Gelfoam altogether.

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