8.7\ Myringoplasty

and Tympanoplasty

8.7.1\ Discussion

Myringoplasty is a simple procedure that is limited to tympanic membrane repair without exploration or manipulation of the middle ear space. Myringoplasty is most often applied to very small tympanic membrane defects caused by extruded tympanostomy tubes. In contrast, tympanoplasty involves reconstruction of the tympanic membrane with concurrent middle ear exploration and possible ossicular chain reconstruction. Several types of tympanoplasty procedures can be performed, which are depicted in Figs. 8.13, 8.14, 8.15, 8.16, 8.17, 8.18, 8.19, and 8.20 and described in Table 8.1. Among these, Type 1 and Type 3 tympanoplasties are overwhelmingly the most commonly performed. Some forms of mastoidectomy may be performed concurrent with tympanoplasty if chronic suppurative otitis media and/or cholesteatoma is present.

The most common materials used for tympanoplasty include autologous temporalis fascia and auricular cartilage grafts—with the later gaining

progressive popularity among ear ­surgeons when dealing with chronic middle ear disease due to their resistance to the effects of negative middle ear pressure. Tympanoplasty grafts appear slightly thicker than the normal native tympanic membranes, especially if cartilage is utilized. However, excessive thickness may signify scarring within the middle ear or postoperative myringitis. Silastic sheeting is sometimes implanted during tympanoplasty in order to prevent the formation of adhesions as part of a staged surgical process wherein removal is performed months later during a sec- ond-stage middle ear exploration and ossicular chain reconstruction procedure.

High-resolution CT is the main imaging modality used for studying the architectural changes from tympanoplasty and evaluating suspected causes of graft failure and persistent conductive hearing loss, such as recurrent perforation, middle ear effusion, tympanosclerosis affecting the ossicular chain, tympanic membrane lateralization, and tympanic membrane blunting. The latter two of these are more likely to be encountered if canaloplasty was performed at that same time as tympanic membrane repair or if the malleus has been completely removed.

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Fig. 8.14  Type I tympanoplasty with cartilage graft. Axial CT image shows the reconstructed posterior portion of the left tympanic membrane as a thick sheet (arrow). Note the relative thickness of the normal anterior portion of the tympanic membrane

Fig. 8.16  Iatrogenic intratympanic cholesteatoma following tympanoplasty. Coronal CT image shows expansile soft tissue (arrow) along the inferior tympanic annulus, splaying the tympanic membrane graft

Fig. 8.15  Type I tympanoplasty with silastic implant for preventing adhesions. Axial CT image shows the implant (arrow) inserted into the middle ear cavity, medial to the reconstructed tympanic membrane (arrowhead)

Fig. 8.17  Type II tympanoplasty. Coronal CT image shows the long process of the incus (arrow) in contact with the tympanic membrane graft

Fig. 8.18  Type III tympanoplasty minor columella with bone strut. Coronal CT image shows a bone graft (arrow) interposed between the tympanic membrane and stapes head

Fig. 8.19  Type III tympanoplasty stapes columella. Axial CT image demonstrates a reconstructed tympanic membrane with cartilage graft applied directly to the head of the stapes (encircled)

Fig. 8.20  Type IV tympanoplasty. Coronal CT image shows the tympanic membrane graft applied to the stapes footplate such that the footplate is exteriorized into the mastoid cavity and external auditory canal. Note the small middle ear space (cavum minor) created during Type IV tympanoplasty

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Table 8.1  (continued)

VSame as type IV tympanoplasty except stapes footplate is removed and oval window is sealed with soft tissue graft. Performed when the stapes footplate is ankylosed

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