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Congenital cholesteatoma, which arises from embryonic epidermoid tissue, is rare. In the majority of cases the cholesteatoma is acquired. It may develop as a retraction pocket involving the whole membrane, as a result of migration over the perforation edges or as basal cell invasion behind an intact membrane. There is no evidence for a metaplastic process or a Langerhans' cell mediated origin. Treatment modalities include several methods of either conservative or radical surgery, the main aim being one-stage total eradication of cholesteatoma and simultaneous reconstruction. With appropriate surgical methods recurrence figures after 5 years should remain under 10%. The patient's own tissues are the material of choice in the reconstruction.

Normal cochlear function was preserved in a patient after excision of the membranous canal from a huge fistula at revision surgery eight years after the primary procedure. A recurrent cholesteatoma had eroded the entire prominence of the horizontal canal and surrounded its membranous portion. The cholesteatoma, including the membranous canal, was removed in a one-stage procedure. The open ends of the bony canal were sealed with a fascia soaked in fibrin glue. After initial dizziness and severely reduced hearing, the patient quickly recovered, with normal bone conduction and a stable 30-dB hearing level by air conduction. The lumen of the membranous canal was patent, and only the ampullar end was atretic. Presumably, the fistula became separated from fluid spaces by formation of perilymphatic partitions and by collapse of the membranous labyrinth adjacent to the fistula.

Mastoid obliteration is recommended as a routine procedure in all mastoid surgery. Bone chips from the mastoid tip, bone paté from the cortical bone and lyophilized dura can all be employed effectively to fill the epitympanic space and Traumann's triangle. The former annulus is reconstructed using lyodura and periost-bearing bone and the canal wall is fortified and the cavity filled with the metally based postauricular musculoperiosteal flap. Any remaining cavity is filled with bone chips and bone paté.

Revision surgery was performed in 185 ears which had earlier undergone a total of 276 tympanomastoid operations. An open cavity had been made in 98, obliteration in 44 and canal wall up surgery in 43 ears. All ears were now operated upon by the open method combined with ear canal reconstruction and mastoid obliteration. Mastoid cholesteatoma was found in 50% of the open cavities and in 63% of intact canal wall ears, while 80% of the obliterated ears showed mastoid retraction pockets with cholesteatoma. Semicircular canal fistulae occurred in all groups, most frequently in open cavities (11%). During the follow-up period after revision (average 5 years) 3% were reoperated upon because of a new cholesteatoma. In the whole series, average hearing levels were slightly better postoperatively and in 34% of the ears the A-B gap was 20 dB at most. The main reason for failure after primary surgery was inadequate mastoid and epitympanic bone work and failure to obliterate the medial parts of the cavity thoroughly.

On 100 pathological ears with tympanic membrane perforation, eustachian tube functions was measured by using sonotubometry and the negative pressure equalization test in an attempt to compare these two methods. The pressure equalization test did not appear to be a reliable tool for preoperative clinical determination of tube function because sonotubometry showed tubal opening in 85% (myringoplasty group) and in 49% (radical surgery group) of patholoical ears, which were not able to equalize negative middle ear pressure at all during swallowing. The negative pressure equalization test is considered to be unphysiological and may produce a locking phenomenon of the tube. Even a small negative pressure can act like a valve, producing an obstruction that muscle activity of the tube is no longer able to overcome particularly when mucosal changes are present in the tubal orifice. Sonotubometry is a physiological test and as such gives a reliable picture of the opening of the tube during swallowing. Data on tympanic aeration postoperatively will be reported later.

Mucosal biopsy specimens were taken from 75 ears undergoing surgery for chronic ear disease. The specimens were studied for squamous epithelium under the operation microscope, and findings during surgery were recorded for comparison with the results of the histologic examination. In 13 ears (17.3%) the histologic study disclosed squamous epithelium in the biopsy specimens that had been clinically judged to be free of such epithelium. Most specimens contained full-thickness squamous epithelium with some surface keratin. In some specimens up to 3 mm long strips of squamous epithelium without granular cell layer were observed. These areas represented the advancing front of squamous epithelium capable of producing mature squamous epithelium. The positive specimens were all well separated from the clinical cholesteatoma and were either extensions over the perforation edges or from the cholesteatoma epithelium in the middle ear or mastoid. Apparently, this unrecognized and nonremoved squamous epithelium is the main reason for the high incidence of cholesteatoma recurrence reported by some surgeons.

The function of the Eustachian tube was tested preoperatively by sonotubometry in 100 ears subjected to surgery for chronic ear disease. 36 ears showed no tubal passage for sound during swallowing and the surgical intervention revealed cholesteatoma in 17 of these cases. In 64 cases sonotubometry gave positive results preoperatively and among these cholesteatoma was found in 26 ears. One patient had a continuously patent tube with typical symptoms and only cutting of the tensor veli palatini muscle tendon revealed the symptoms after reconstructive ear surgery. In another patient the tube opened well on swallowing, remained patent for some time, and closed slowly. This finding was unexpected and the patient had no complaints associated with the tubal function. The patulous tube is a rare condition (1-2%) in patients with chronic middle ear disease but should be diagnosed before surgery and followed carefully postoperatively.

This cholesteatoma series comprises 84 ears, 81 of which had a labyrinthine fistula and 3 a horizontal semicircular canal opening that arose as a surgical complication. In 49 ears (58.3%), the operation was a primary one; in 35 ears (41.7%), it was a revision. Of all ears, 21 (25%) were deaf preoperatively. The fistula was located in the horizontal canal in 76 ears (90.4%). The matrix was removed in all these ears, and the fistula was covered with fibrin glue and fascia or periosteum. Hearing was preserved in all 57 ears in which matrix removal was carried out as the planned last stage. These included three ears in which the membranous canal was cut deliberately. Surgery that was performed against established rules caused deafness in three ears. Accidental opening of the horizontal canal caused no sensorineural loss in two ears as the fistulas were sealed immediately, while one ear in which the opening was not immediately recognized became deaf.

Three temporal bones were serially sectioned to study the postoperative fate of the meatally based postauricular musculoperiosteal flap. In all three ears, the flap sealed off the middle ear effectively from the mastoid cavity and in one, with resected canal wall, formed a new soft posterior wall with good meatus. All flaps contained viable muscle, fat, collagen, reticulin, and elastin, and were richly vascularized. In two flaps, small granulating foci of infection were noted. In two temporal bones, from a child with hypogammaglobulinemia, small cholesterol cysts formed behind the falp during the delayed healing of the mastoid wounds.

Ceramic stems, their lateral end capped with a modelled ossicle, or ceramic prostheses manufactured with a cap-shaped head were used as a columella from the stapes footplate to the tympanic membrane or a fascia graft in 41 ears operated on during 1982-1985. Six ears had no membrane perforations and no severe disease of the tympanic mucosa. Twelve ears underwent primary operations for cholesteatoma and 23 ears had revision surgery. Good hearing improvement occurred in well-aerated ears while hearing in ears with extensive tympanic disease did not improve after surgery. No tissue reactions to the ceramic prosthesis were observed and no prosthesis was extruded. Ceramic can be regarded as an acceptable alternative to bone for columella grafts used in surgery for chronic middle ear disease when the stapes superstructure is missing.

Aeration of the tympanic cavity was studied after 81 operations were performed on ears with cholesteatoma, in which sonometry was used preoperatively to measure the eustachian tube (ET) function. Twenty-nine of the 44 ears in which all or part of the tympanic mucosa could be preserved had positive sonometric test results, and 25 ears (86%) retained satisfactory aeration. Eight (53%) of the 15 ears with negative test results showed good postoperative aeration while adhesive changes developed in seven ears (47%). In 37 ears after the removal of all tympanic mucosa, aeration was satisfactory in eight (55%) of the 15 ears with positive sonometric test results, whereas only three (14%) of the 22 ears with negative test results developed an aerated tympanum. A positive sonometric test result can be regarded as a fair prognostic indicator of normal ET function. In extensive tympanic disease, there is a clear correlation (86%) between a negative test result and postoperative adhesion.

Opinion differ whether simple myringoplasty should be combined with mastoidectomy, which is claimed to provide a large air reservoir for the middle ear. Data are reported on 61 ears, 55 of which had reasonably normal tympanic mucosa but distinct chronic mastoid or epitympanic ear disease. Obliteration of the cavity was performed, combined with tympanoplasty, and the patients were followed up for an average of three years. Normal aeration of the middle ear was seen in all cases with normal middle ear mucosa regardless of whether the posterior canal wall was saved or reconstructed in connection with obliteration. It is concluded that there is no reason for mastoidectomies in small mastoid cell systems in simple myringoplasties.