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A partially implantable middle ear implant using an ossicular vibrator of a piezoelectric ceramic bimorph has recently been developed in Japan as a new rehabilitative method for hearing. Four patients at the Miyazaki Medical College Hospital were implanted with this device between September 1994 and October 1996. Implantation of the internal component was performed under local anesthesia after confirmation of sufficient sensitivity to the ossicular vibrator in an intraoperative vibratory hearing test. All patients regained socially useful hearing with the middle ear implant without any foreign body reactions or recurrence of otitis media. None of the cases showed any elevations of bone conduction thresholds 2 to 4 years postoperatively. Natural and clear sounds without interference noise and howling due to acoustic feedback were highly satisfactory in all patients. However, the first case, who had an implant in an ear following cholesteatoma surgery using the intact canal wall technique, experienced about a 10dB deterioration of the average hearing level with the implant 2 years after implantation. Gradual deterioration appeared to be caused by the retracted tympanic membrane interfering with the mobility of the ossicular vibrator. The following three cases were implanted in ears previously operated on by radical mastoidectomy, showing stable or improving hearing results with the implant. Closure of the external canal skin at the cartilaginous portion at the time of implantation seemed appropriate to maintain a sufficient middle ear space for the ossicular vibrator to work properly. Our case study confirms that the partially implantable middle ear implant is a safe and useful tool for patients with mixed deafness which cannot be satisfactorily rehabilitated by tympanoplasty and/or a conventional hearing aid.

ウログラフィン治療に対する反応性を見る目的で, 本剤単独療法で治療後一週間以内に治癒ないし著明回復に至った突発性難聴症例を, 早期反応群として臨床的特徴を検討した。発症から治療開始までの期間や年齢には他の群と有意差なかったが, 早期反応群にはめまいの随伴例が1例もなく, 女性より男性に多い傾向が認められた。早期反応群の治療前の聴力像は4000Hzと8000Hzの閾値が比較的保たれる傾向がある一方, 反応不良群との間に有意差を認めた。早期反応群の聴力改善は250Hz, 500Hz, 1000Hzに顕著に見られ, 治療後一週間でほぼ固定時聴力まで達していた。これらの特徴は, 性差を除けば予後良好の突発性難聴一般に共通したものであり, ウログラフィンに反応する内耳病態が特殊なものではないことが示唆された。

This case study describes a therapeutic strategy using a cochlear implant for a bilateral acoustic neuroma deafened patient. The cochlear nerve had previously been sacrificed on one side during tumour removal, but on the remaining side a functioning cochlear nerve was assessed by electric promontory stimulation in spite of a neuroma extending into the vestibular labyrinth. The patient was successfully stimulated with a Nucleus 22- channel implant after removal of the intracanalicular portion of the neuroma via a middle fossa approach.

Takahashi reported that in surgical treatment of cholesteatoma by the canal up method, postoperative aeration of the mastoid cavity depends only on preservation of the mastoid mucosa and not on the ventilation routes made by anterior and/or posterior tympanotomy. Takahashi suggested that aeration of the mastoid is maintained by the gas exchange function of the preserved mucosa. In this paper, my refutation of Takahashi's theory will be described as follows:1. His citation of the literature is limited to papers which support his theory.2. His cases are too few in number to make any negative recommendation regarding the clinical suitability of anterior tympanotomy in cholesteatoma surgery.3. His conclusion is one-sided and ignores data incompatible with his theory.My opinion is that a new ventilation route between the eustachian tube and the epitympanomastoid cavity made by anterior tympanotomy is much more effective than the gas exchange via the mucous membrane for aeration of the postoperative tympano-mastoid cavity after cholesteatoma surgery.

When the intact canal wall technique (ICWT) is applied for patients with a low-lying middle f ossa dura, a very narrow space between the posterosuperior bony ear canal and the low-lying dura occasionally hampers the transmastoidal approach to the attic. In such cases, the minimum removal of the lateral part of the posterosuperior bony canal wall is required to complete safe drilling toward the tympanic tegmen, the posterior tympanotomy and the anterior tympanotomy for total removal of cholesteatomas. Because the medial part of the bony ear canal including the scutum can be preserved in most of the cases, the postoperative condition of the ear canal and reconstructed tympanic membrane following this procedure is identical to that following ICWT. Preoperative CT scan is useful for evaluating the extent of bony removal requiring for surgical access to the attic.

陰イオン性血管造影剤による突発性難聴の治療成績が, 治療的診断に資するに値するものであること, その作用部位は蝸牛血管条血管内壁以外にありえないことから, 本症の病変部位は血管条血管内皮細胞と推論した。 陽性荷電金コロイドを用いた電顕的観察で, 内皮細胞内腔面にシアル酸糖鎖による, 基底膜にピアルロン酸糖鎖による陰性荷電部位を認めた。 また血管条構成細胞は陽性荷電していることから, 血管条にionic charge barrierがありEPを維持しているものと推定した。 突発性難聴はこのバリア-破綻によるEP低下で発症し, 血管条が能動輸送能を残しており, 内腔面が受動的に陽性荷電すると陰性荷電造影剤はイオン性に付着し, 治療効果を発揮するものと推論した。 すなわち突発性難聴は血管条血管内皮細胞の糖鎖代謝障害による関門破綻によるものと結論した。

Using a biochemical technique, the authors characterized and identified the plasminogen activator (PA) derived from tissue extracts of six aural cholesteatomas. The results of fibrin zymography indicated that the tissue extracts of two cholesteatomas demonstrated two lytic zones on fibrin-agarose plates. One of the lytic zones was at about 72 kd, while the other zone was at about 64 kd. Using various goat immunoglobulin G (IgG)-containing antibodies (anti-human uterine tissue type PA (t-PA), anti-human low-molecular-weight (LMW) urokinase, and nonspecific goat IgG) and plasminogen-free fibrin-agarose plates, we confirmed that the cholesteatoma tissue extracts contained 72 kd t-PA and 64 kd urokinase type PA (u-PA). Furthermore, we measured the t-PA and u-PA activities in the tissue extracts selectively by parabolic rate assay. In order to estimate the PA activity, we developed optimal conditions for this assay. The specific t-PA activity ranged from 0.03 to 0.43 mIU/micrograms-protein and the specific u-PA activity ranged from 0 to 0.35 mIU/microgram-protein. The highest percentage of u-PA with respect to the total PA activity was 44.9%. However, in four of the six cases, we failed to detect u-PA activity. In the present study, we thus clarified the presence of PAs in tissue extracts of aural cholesteatomas. Furthermore, we confirmed that measureable u-PA occurred in some tissue extracts. We anticipate that the u-PA in inflammatory tissues plays an important role in the degradation of the extracellular matrix via the formation of plasmin and collagenases.

Intracellular free Ca2+ concentration ([Ca2+]i) in spiral ganglion cells (SGC) of guinea pig was measured using the fura-2 fluorescence method. Application of high-K+ external solution increased [Ca2+]i. [Ca2+]i elevation was suppressed by either depletion of external Ca2+ or application of the dihydropyridine Ca2+ channel antagonist, nicardipine. One of the putative hair cell afferent nerve neurotransmitters, L-glutamate (Glu), induced [Ca2+]i elevation in SGC. Pharmacological studies suggested that the Glu receptor may be a non-NMDA subtype. Glu-induced response was suppressed by either depletion of external Ca2+ or application of nicardipine, indicating that Glu-induced [Ca2+]i elevation is mainly carried out by the voltage-dependent Ca2+ channel in SGC.

To evaluate biochemical changes of inner ear fluid following perilymphatic fistula (PLF), free amino acid (FAA) profiles of perilymph in experimental PLF were determined using high performance liquid chromatography (HPLC). Thirty-five guinea pigs were anesthetized and prepared as PLF models by perforating the round window membrane (RWM) of the left ear. Right ears served as controls. Samples (2 microliters) were aspirated from scala tympani through a RWM perforation. Animals were divided into two groups according to time of sampling following PLF induction: 2-week group (n = 17) and 4-week group (n = 18). Compound action potential (CAP) evoked by 1, 2, 4 and 8 kHz tone bursts were measured using a round window electrode from the left ear before PLF induction and from both ears before final sampling. RWM perforations were completely closed at the time of the final sampling in 8 of 17 animals from the 2-week group, and 15 of 18 animals from the 4-week group. In comparison with that in control ears, concentrations of FAA throughout all profiles was dramatically elevated in the PLF ears with a healed RWM perforation. Most PLF ears with persistent RWM perforation showed minimal differences between 2-week and 4-week groups. No remarkable CAP threshold changes were found at any frequencies tested following PLF induction in both the 2-week and 4-week groups. The unchanged 8 kHz threshold suggests that FAA concentration increases only at the basal end of the cochlea. FAAs accumulate within the basal end of scala tympani in ears with a healed RWM.(ABSTRACT TRUNCATED AT 250 WORDS)

Between 1987 and 1993, 71 ears of attic type cholesteatoma and 20 ears of adhesive type were operated on using the intact canal wall technique combined with anterior tympanotomy. Pre- and postoperative pure tone hearing after the surgery were analyzed, especially to determine whether anterior tympanotomy is harmful to the inner ear. Mean values of 500, 1000 and 2000Hz of air conduction threshold immediately, before and about 1 year after the operation were compared. In attic cholesteatoma, type 1, type 3, and type 4 of ossiculoplasty revealed significant improvement of 8.4dB, 9.3dB, and 8.0dB respectively. In adhesive cholesteatoma, results obtained were 8.4dB, 0.8dB, and -3.0dB. Differences between pre- and postoperative bone conduction threshold at 4000Hz were 1.5dB in type 1, 1.3dB in type 3, and 5.0dB in type 4 in attic cholesteatoma. Those in adhesive cholesteatoma were -2.5dB, -0.2dB, and -10.0dB respectively. From the results obtained, we concluded that (1) our results were satisfactory with regards to hearing ability following all types of ossiculoplasty in attic cholesteatoma and in type 1 in adhesive cholesteatoma, (2) anterior tympanotomy itself is not a harmful procedure to the inner ear in both types of cholesteatoma, (3) an increase in bone threshold in adhesive cholesteatoma is due to the surgical procedure at the stapes and/or the oval window.

The blood-cochlear barrier, which consists of the molecular size and ionic charge barriers, is known to play an important role in production and absorption of inner ear fluids. In this study, we employed poly-L-lysine colloidal gold conjugates (PL-CG) in combination with Lowicryl K4M resin to demonstrate anionic sites in blood capillaries of the cochlear duct. Male ICR mice weighing 30-40 g with a positive Preyer's reflex were used. The basement membranes of blood capillaries of the stria vascularis and the spiral ligament were successfully labeled with PL-CG pH 2.5. The luminal surface of capillaries in the stria vascularis and the spiral ligament intensely reacted with PL-CG pH 2.5. However, PL-CG pH 1.0 stained only the basement membrane of the spiral ligament. Predigestion with several glycosidases nearly eliminated PL-CG labeling. Anionic charge located on the luminal surface of the endothelial cell was mainly caused by the presence of sialic acid. On the contrary, anionic charge of the basement membrane was caused in a substantial degree by chondroitin and heparan sulfate-rich glycosaminoglycans. We obtained histochemical evidence that blood capillaries of the stria vascularis differ from those of the spiral ligament.

Twenty-three patients with bilateral recurrent laryngeal nerve paralysis treated at our clinic over the past 15 years were studied. The vocal cord was fixed in a paramedian position in twelve patients, in a median position in ten patients and in our intermediate position in one patient. No surgical treatment was performed in ten patients, while thirteen patients were surgically treated. Surgical procedures were undertaken as follows: tracheotomy in three patients, endoscopic lateralization of the vocal cord by Kirchner's method in two patients, widening of the anterior glottis combined with Woodman's operation in one patient, arytenoidectomy in five patients, thyroplasty type I (Isshiki's method) in one patient, glottic closure in one patient and laryngectomy in one patient. From our long term observations, we think that arytenoidectomy is the simplest and most reliable method for reducing the laryngeal obstruction in bilateral recurrent nerve paralysis.

Although many theories on the etiology of sudden deafness have been proposed, the main pathological focus remains uncertain. In this study, MR examinations were performed on patients with unilateral sudden deafness to study the relationship between MRI findings and response to treatments, i.e. amidotrizoate, steroid, or both. In 7 out of 30 cases, the cochlea and/or the vestibule showed higher signal intensity on proton density and T2-weighted images on the diseased side (MRI positive cases). These findings suggest changes in the chemical composition of the perilymph and/or the endolymph, since proton density and T2-weighted images reflect water content. It appears that MRI positive sudden deafness is more difficult to cure even with the use of amidotrizoate or steroid than MRI negative sudden deafness. Amidotrizoate seems to be more effective in MRI negative sudden deafness. MRI would help us to further classify the etiology of sudden deafness.

The present study was undertaken to investigate the role of collateral arteries in cochlear circulation by examining the effect of occlusion of branches of the basilar artery on endocochlear DC potential (EP) and cochlear blood flow (CBF). EP and CBF were measured at the basal turn of the cochlea during microclamp occlusion of the basilar artery, its branches and the posterior inferior cerebellar artery (PICA). CBF was measured with a laser Doppler flowmeter. Systemic blood pressure (SBP) increased at occlusion of the basilar artery, but was not influenced by any occlusion of its branches. Changes of EP and CBF at occlusion of the basilar artery were classified into two types: recovery type and non-recovery type. Thirty-five guinea pigs were classified into three groups according to the number of branches of the basilar artery: Group A with one branch in 10 animals (29%), Group B with two branches in 20 animals (57%), and group C with three branches in 5 animals (14%). From the results obtained at successive occlusions of branches of the basilar artery and PICA, it is clear that the anterior inferior cerebellar artery (AICA) supplies blood to the cochlea more or less in all animals, although the reduction of the blood volume by its occlusion is not enough to decrease EP in some animals. When vascular dysfunction occurs in AICA of such animals, other branches of the basilar artery and/or PICA will play an important role to maintain cochlear circulation.

For voice restoration after total laryngectomy, a new surgical procedure of a tracheopharyngeal shunt using an inverted epiglottic mucosa was reported. The epiglottis is conserved with a pedicle at the tongue base. Next, the epiglottic cartilage is extracted submucously, and the mucosal tube is inverted. The posterior margin is sutured with the upper end of the hypopharyngeal mucosa, making the new esophagus. The suture is covered by the sternohyoid and thyreohyoid muscles kept at the hyoid bone, making the new arytenoid. The inverted epiglottic mucosal tube is then anastomosed with the tracheal stump, making the shunt. With this technique, voice can be restored soon after surgery without aspiration. Fluoroscopic studies have revealed that the shunt was located at the tongue base and was covered closely during swallowing.

Superficial siderosis of the central nervous system (SSCN) in a disease characterized by chronic deposition of hemosiderin in the leptomeninges, subpial tissue, spinal cord, and cranial nerves. Previously the diagnosis of SSCN could only be made at autopsy or during a neurosurgical procedure. Now, however, a diagnosis of SSCN can be made non-invasively by magnetic resonance imaging (MRI). We present the case of a 50-year-old male with SSCN accompanied by bilateral sensorineural hearing loss which gradually progressed to total deafness over a seven year period. This patient also had associated bilateral caloric weakness with episodes of severe recurrent headaches over the two preceding years. The deafness and gait disturbance, which were his chief complaints, were followed by other neurological manifestations including pyramidal tract signs, anosmia, and ageusia. High-field MRI on T-2 weighted images of the CNS showed diffuse marginal hypointensity of the cerebrum, brain stem, and cerebellum. Atrophy of the cerebellum and brain stem was also apparent. Low signal intensity along the proximal segment of the acoustic nerve and the facial nerve was noted from the cistern to the internal auditory canal. Neither bilateral transtympanic promontory nor round window electrical stimulation elicited any sound sensation. In this case it was thought that the acoustic nerve alone or both the acoustic nerve and the cochlea were affected by this disease. Consequently, cochlear implantation was not indicated. The source of bleeding into the subarachnoid space could not be detected despite thorough examination. This diagnosis will be made only by physicians who are aware of this rare entity and have knowledge of the characteristic clinical pathology.(ABSTRACT TRUNCATED AT 250 WORDS)

騒音レベル80-100dB (A), 中心周波数250Hz-4kHzの某新聞社輪転機室就業員24人の聴力レベルの変動を8年間にわたり追跡した。 24人中21人は聴力レベルに大きな変化なく, 年齢による生理的聴力損失にほぼ添う経過であった。 3人にc5 dipがみられたが, 難聴の発現, 進展時期に関しては個人差が大きく, 一定の傾向はなかった。 4kHzと8kHzの聴力レベルは, c5 dipのある者で各年ごとのばらつきが大きく, 聴力正常な者ではばらつきが小さかった。 また, 2例にc5 dipの深さに左右差があった。 これらはこの個体が 「c5 dipが始まり固定するまでの期間内」 にあること, 言い換えれば内耳損傷がなお現在進行していることを示すものと思われた。 また, 耳栓使用で騒音性難聴発生が抑制できることが改めて確認できた。

情報化社会といわれる今日の社会構造の変化は, 新たな騒音環境を形成し, 社会医学としての聴覚医学の分野にも新たな問題が生じつつある。 今回我々は, 1977年から1990年までに当科を受診し, 音響外傷・騒音難聴・職業性難聴・c5-dipを含む広義の騒音性難聴の診断をえた316人548耳を対象に, 騒音性難聴の原因の年次的変化の検討を行い, 社会構造の変化と騒音性難聴の出現について若干の考察を加えた。 対象は男性287人499耳, 女性29人49耳。 年齢は6歳から75歳平均47.7歳であった。 患者数はやや増加傾向があり, 高齢者や軽症例の受診増加が原因と考えられた。 また従来の重厚長大型工場騒音による職業性難聴患者は減少し, 代わりに騒音曝露を自覚しない患者の増加を認めた。 これはまだ明らかにされていない原因が潜んでいるためと推測され, 10歳未満の症例の出現や女性の社会進出に伴う患者数の変化とともに, 今後の研究が必要な点であると考えた。

Sixty-three patients with foreign body sensation in the throat showing no marked organic diseases were asked about their complaints, the period of onset, therapeutic efficacy etc. All patients were examined by high-voltage radiographs of the pharyngolarynx and classified into six types. We separated the patients into a treated group and a non-treated group. The drugs used were lysozyme chloride only or alprazolam in addition to it.1. There was no sex difference, the average age was 53.0 years.2. There was no significant difference in improvement rating for subjective symptoms between the treated group and the non-treated group. The spontaneous remission rate in the non-treated group was about 32%.3. There was no significant difference between the radiographic classification groups.4. The longer the period from the onset, the lower the thrapeutic effect.5. It is very important to explain to patients thoroughly that there are no serious diseases in the throat and to show them the results of radiological examinations and to relieve cancer-phobia.

Investigation of Prussak's space and its relationship to adjacent spaces is important in elucidating the cause of retraction pocket and cholesteatoma formation in this space. This study was designed to quantitatively characterize the chronological development of Prussak's space and its relationship to adjacent spaces in temporal bones. One-hundred and forty-nine human temporal bone slides (115 normal, 28 with otitis media with effusion, three with retraction pockets and three with attic type cholesteatoma) including specimens ranging from fetal to adult bones were studied. Prussak's space was formed and sufficient aeration routes established by 4 years of age in normal temporal bones. In temporal bones with otitis media with effusion, however, the growth of Prussak's space was suppressed and few routes for aeration established until 10 years of age. In normal temporal bones, Prussak's space developed with aeration routes sufficient to avert the negative pressure which can result in retraction pocket formation in the pars flaccida of the tympanic membrane.

A new type of stapes prosthesis made of nickel-titanium shape memory alloy wire was developed and its biocompatibility was examined in 24 ears of 12 cats. The prosthesis was implanted at the long crus of the incus. The incus was examined 27–355 days after operation. In 23 ears, the prosthesis was found macroscopically well implanted at the aimed position. In one ear the prosthesis was found to be dislocated and in another the prosthesis was slightly loosened. The incudes were removed and five specimens were prepared for scanning electron microscopy and the other specimens were observed under light microscopy. Histological studies revealed severe bone resorption of the long crus in the dislocated case and moderate bone resorption in the slightly loosened case. These bone resorptions were found to be caused by the inadvertent removal of the mucosal membrane during the implant operations. In seven ears under a light microscope and in one ear under a scanning electron microscope, slight bone resorption as bone erosion was seen at the contact area of the prosthesis. This bone resorption was induced by the mechanical pressure of the prosthesis and was not progressive due to fading of the pressure of the prosthesis. With the exception of pressure induced bone erosions, there was no progressive bone resorption which was prosthesis induced. The biocompatibility of the nickel-titanium alloy stapes prosthesis with the long crus of the incus was proved. The prosthesis should be implanted loosely at the long crus of the incus without removal of the mucosal membrane.

The temporal bone comprises five parts: (1) a squamous portion, (2) a petrous portion, (3) a tympanic portion, (4) a mastoid portion, and (5) a styloid portion. The petrous portion is the most important in radiology for cholesteatoma; it houses all of the inner ear, the epitympanic cavity, and the supratubal recess in the protympanum. Anterolaterally the petrous connects with the the tympanic portion at the petrotympanic fissure (Glaserian fissure), which forms the passage for the chorda tympani and the anterior tympanic artery. Posteriorly, it connects with the squamous portion at the petrosquamous suture, which remains as Koerner’s septum, projecting into the superior portion of the mastoid antrum to form a surgical landmark.

Surgery for cholesteatoma began with radical operations and then conservative radical operations were developed. After proposal of the so-called canal-up technique for chronic otitis media in the 1960s, this technique was used with great expectations even for cholesteatoma. In particular, Jansen’s (1967) posterior tympanotomy technique and Sheehy’s “intact canal wall” technique (Sheehy and Patterson 1967) have tended to the so-called canal-up or “closed” techniques. During the latter half of the 1970s, however, an increasing number of adverse reports began to appear that revealed alarmingly high incidences of both recurrent and residual cholesteatoma. Thus, many improved techniques were presented such as the mastoid obliteration technique (Palva 1973), the combined approach tympanoplasty (Smyth 1976; Sade 1982), osteoplastic epitympanotomy (Wullstein 1974), the canal-down with reconstruction technique (Suzuki, 1982), the lateral tympanotomy technique (Tos 1982; Bhide 1982), and so on. No reliable technique has been reported, however, that makes use of a canal-up method in an operative procedure for cholesteatoma for general use by otologic surgeons.

Diagnostic criteria for recurrent cholesteatoma are as follows: (1) the patient will have undergone a previous surgical procedure to treat attic or adhesive cholesteatoma; (2) the same type of cholesteatoma is then found during reoperation; (3) the cholesteatoma clearly communicates with the retracted pars flaccida or pars tensa.

There are several different theories that attempt to explain the etiology of cholesteatoma. The three most popular original theories are (1) the retraction pocket theory states that cholesteatoma forms by accumulation of debris in retraction pockets arising from Shrapnell’s membrane or from the adhered pars tensa, caused by occlusion of the eustachian tube (Bezold 1908); (2) the migration theory states that squamous epithehum which has migrated into the middle ear through a perforated tympanic membrane proliferates there (Habermann 1889); and (3) the metaplastic theory states that squamous metaplasia of the middle ear mucosa forms following chronic inflammation (Wendt 1873).

In this chapter, surgical findings in anterior tympanotomy on the tympanic diaphragm, especially on the partition attached to cholesteatoma near the supratubal recess, are explained and discussed. As cholesteatoma develops (usually in the poorly pneumatized ear), these intraoperative results can be used in place of anatomical landmarks on the tympanic diaphragm. In this study, we measured the bony partition removed during anterior tympanotomy using angled sounds with tips 3, 4, and 5 mm long. The length of the bony partition, the width of the drilled rough bony surface (indicating thickness of the bony partition at the base), and the size of the supratubal recess were measured.

We present a 76-year-old male patient with adhesive-type cholesteatoma and with metal foreign bodies which were shown to be located in the bony eustachian tube by computed tomography. He sustained a burn injury of the left tympanic membrane when he was struck by a bomb 52 years ago, during World War II. The cannonball fragments that entered the tympanic cavity were apparently transported to and stuck in the eustachian tube isthmus by mucociliary action after spontaneous closure of the tympanic membrane perforation. Persistent tubal obstruction due to the impacted foreign bodies and surrounding granulation tissue seems to have caused chronic adhesive otitis, leading to cholesteatoma which developed in the attic and mastoid antrum. No foreign bodies became visible after cholesteatoma removal by an intact canal wall technique in conjunction with anterior tympanotomy for wide exposure of the supratubal recess and the tympanic osteum of the eustachian tube. Therefore, anterior tympanotomy was further extended anteriorly to open the enlarged bony eustachian tube, allowing visualization and safe removal of two cannonball-fragments firmly impacted within it. We call this surgical approach to the bony eustachian tube "extended anterior tympanotomy". The transmastoidal accessibility of the bony eustachian tube produced by this technique should be assessed by preoperative computed tomography.

The chronological developmental processes of endocochlear potential (EP) and negative endocochlear potential (-EP) were investigated as a function of age from birth in the basal and second cochlear turns in normal ICR-strain mice. The EP of the basal turn developed between 5 and 17 days after birth (DAB). The -EP of the basal turn attained to its mature level on 11 DAB and it increased its absolute value further between 12 and 16 DAB and then, recovered to its mature level again on 20 DAB. The developmental processes of EP and -EP of the second turn followed similar courses to those of the basal turn although they were several millivolts different on each day in detail. The results suggest that the developmental processes of the +EP and the -EP are different. The time of reaching minimum -EP during anoxia were measured and the rate of EP decline were calculated on each animal. The rate of EP decline increased rapidly on 10 DAB, almost coinciding the day which EP began to increase abruptly. Although the rate of EP decline is influenced by several processes, this result showed one of the possibility that the sensitivity of the stria vascularis to hypoxia may develop parallel to the development of the EP.

This study was designed to show MRI findings of postoperative middle ear pathologies and to discuss the usefulness of Gadolinium-enhanced MRI in evaluating the postoperative state of cholesteatoma. Thirty-eight ears which underwent intact canal wall tympanoplasty for cholesteatoma were examined. Recurrent cholesteatoma was detected as an iso-intensity area on T1-weighted images with negative enhancement. Notably, residual cholesteatoma were generally depicted as a round iso-intensity area with negative enhancement. Residual cholesteatoma less than 5mm in diameter were, however, not generally detectable with our MRI scanner. Granulation tissue can be separated from cholesteatoma as an area with positive enhancement. Cholesterol granuloma shows a characteristic high signal pattern on both T1 and T2-weighted images. Hypovascular fibrous tissue and fluid collection may be depicted as a pattern similar to that of cholesteatoma. However, the signal is usually more homogeneous than that of cholesteatoma. We conclude that Gadolinium-enhanced MRI is useful for detecting postoperative cholesteatoma and avoiding unnecessary second-look operations after cholesteatoma surgery, by the canal-up procedure.

Our 11 years of experience of myringoplasty in 87 children aged 3 to 14 years were retrospectively studied. The children were followed up over a period of 3 years. Children in the 3-to-12-year-old age group had a success rate of 57.7 %. Graft-take rate was 100 % in children operated on at the age of 13 and 14 years. Revision surgery was needed in 33 ears, and ultimate success was achieved in 88.9 %. Within the same period, 38 ears were conservatively treated and 20 perforations of them were spontaneously closed. The state of the opposite ear and the perforation size were not a decisive factor in the results of myringoplasty. Children between 7 and 10 years old with small mastoid pneumatization had a statistically lower graft-take rate. We concluded that myringoplasty is warranted for children 13 years of age and older or children aged 7 to 12 years with large mastoid pneumatization.

Rhinocerebral mucormycosis is a rare and fatal deep fungus infection occurring in debilitated patients. Its reports have been recently increased because of the increase of such conditions as uncontrolled diabetics, leukemia, and cancer. A 60-year-old male suffering from continuous headache and fever was diagnosed as meningitis, and repeated culture of cerebrospinal fluid was negative. Antibiotic therapy was ineffective. CT scan revealed brain abscess in the right frontal lobe and bone defect over the right posterior ethmoidal sinuses. Both maxillary and ethmoidal sinuses were operated on 38 years ago. The patient was suspected to have rhinologic brain abscess. We intended to remove the source of infection in the right posterior ethmoidal sinuses beneath the base of the skull and to repair the defect of dura mater. The operation was tried on the 6th hospital day. There was a cyst in the posterior ethmoidal sinuses and an intact denuded dura mater over the cyst. The causative organism was not detected by smear test, bacteriological and fungal culture. He relapsed into lethargy, and died on the 21st hospital day due to the vast cerebral infarction. Autopsy revealed rhinocerebral mucormycosis. The literature on this disease was also reviewed and discussed.

Cochleograms of guinea pig ears were made 30–40 days after exposure to intense pure tones of 300 Hz, 500 Hz, 2 kHz, or 4 kHz at 130–150 dB SPL for 4–24 h. At 4 kHz, hair cells in the basal turn disappeared totally, in the second turn moderately, and were relatively undamaged in the third and apical turns. At 500 Hz, hair cells in the second and third turns were almost completely injured and at 300 Hz moderately damaged in the third and apical turns although the basal turn remained undamaged. At 2 kHz for 9 h, hair cells were almost completely injured in all turns. Negative endocochlear DC potential (negative EP) induced by furosemide was observed in the basal turn but not in the third turn of animals exposed to 300 Hz. Contrarily, negative EP was observed in the third turn but not in the basal turn of animals exposed to 4 kHz. We conclude that the hair cells of Corti's organ play an essential role in the production of negative EP.