Selection of cases and classification of tympanoplasty.
Meticulous mastoid surgery does not always result in a dry, stable ear. Eustachian tube malfunction has been accepted as an important factor in chronic and recurrent middle ear infection. There are many parameters of eustachian tube malfunction, which form a complicated problem for investigation and analysis. Of most importance appears to be varying degrees of malformation of the nasopharynx and palate. A gradient from mild to overt deformity appears to be related to the degree of eustachian tube function. Other factors, such as nasal infection and allergy, nasopharyngeal scar tissue and tumors, and general resistance to infection, are of less importance but must be considered in the etiology of chronic ear disease. Tympanoplasty is relatively unsuccessful in a chronic discharging ear, as the infection ultimately destroys a surgical repair. Persistent otorrhea can be caused by either eustachian tube malfunction or a reservoir of chronic infection in the mastoid cavity. A mastoidectomy often controls the infection in the mastoid cells and a tympanoplasty may be done as a secondary procedure when the cavity is stable. A careful preoperative evaluation should be made in every case to determine the responsible factors for persistent ear infection. If possible, attempts should be made to eliminate the causative factors prior to the tympanoplasty. Classification of cases into four groups helps to separate those cases with a good prognosis from those that will continue to suppurate and will have a poor functional result. A dual classification of tympanoplasty has been established in which the type of reconstruction is documented and the stability of the ear against infection is estimated. Classified clinical material forms the basis for a clearer representation of the cases under investigation and the results of tympanoplastic surgery become statistically comparable. Classification of cases also aids in the selection of cases for surgery by identifying preoperatively those cases that will be successful from those that may not have a good result. With this information at hand it is possible to more accurately inform the patient preoperatively regarding hearing improvement and control of infection following a tympanoplasty.