Evidence-based medicine (EBM) has emerged as a process to enable clinicians to improve patient-care. EBM involves a series of guidelines that aim to provide the best clinical management for each patient using the best scientific evidence available. Although medicine has traditionally developed via the accumulation of clinical evidence, there has been an increased demand for clinical practice to be evidence-based. For example, Chinese herbal medicine, which is based on the clinical experience accumulated over more than a thousand years, is considered to be less evidence-based than Western medicine because of its lack of Westernstyle evaluation. The basic principle of EBM is that physicians should apply evidence obtained from studies with large numbers of patients.
Consider first, the issue of clinician-discretion. Most clinicians critically appraise the available evidence for medical procedures applicable to their patients. As Osler noted, medicine is an art based on science. General clinicians and most EBM specialists (who are essentially clinicians) are likely to apply the results of these appraisals flexibly, using their “art” in their clinical practice. However, some EBM specialists are inclined to insist that we should uniformly apply that which is regarded as the best evidence to each patient and then evaluate the outcome. If problems occur, the cause should be found and management should be appropriately modified. However, alternative managemennt cannot always be applied due to the potential morbidity and mortality associated with certain medical conditions. It seems reasonable that the application of evidence on a case-by-case basis i.s a reasonable element of the art in clinical medicine.
Evidence is a means rather than an end-in-itself. However, in some situations evidence is regarded as the objective. For example, some doctors may consider that the outcome of treatment is not their responsibility so long as they have provided management according to the appropriate guidelines.
I suggest that it is the ranking of evidence that is the most essential component of EBM. Clinicians are also required to produce evidence. Randomized controlled trials (RCT) are considered to produce evidence of the highest rank. It is not always possible however, perform RCT, especially in surgical settings because of the following reasons:
1. There are limited opportunities to employ alternative procedures when the initial procedure proves to be ineffective or yields an undesirable outcome.
2. Since patients who undergo surgery are generally more unwell and have less opportunity for alternative treatments, lower numbers research participants are expected.
3. There are currently no standards for evaluating differences between hospitals and surgeons.
4. There is currently limited financial support for performing such studies.
Clinicians should therefore always address any available evidence even if its ranking is considered to be low.

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New clinical-epidemiological idea of Evidence-Based Medicine (EBM), the use of current best evidence in making decisions about individual patients, have been spotlighted recently.
On the other hand, the cause and choice of treatment for idiopathic sudden sensorineural hearing loss (ISSHL) is considered to be still controversial. In such background, a therapy for ISSHL is reviewed from the viewpint of EBM. It is concluded that steroid (Dexamethasone) is the only treatment available with a significant beneficial effect on ISSHL in systematic review.
Recommendations are made with regard to a well designed clinical trial on the treatment of ISSHL. There should be a great challenge to otolaryngologist to explore and use the principles of EBM in everyday practice and we will have to wait for further study in this particular area.

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The prevalence of acoustic neuroma (AN) in unselected temporal bones was 0.8% in a well-conducted study. Whereas the yearly incidence of AN is reported at 1/100, 000. The prevalence would be calculated at 0.07%, if the ANs presented at a constant rate of 1/100, 000 of the population over a seventy-year life span. Presumably, the value of overly aggressive testing strategies for detection of ANs in asymptomatic individuals must be questioned. The aim of this study is to examine the cost-effectiveness and relative performance of numerical clinical examinations to diagnose the AN.
The auditory brainstem response (ABR), as well as associated audiologic and radiographic studies of 743 suspected of having AN were reviewed. From January 1, 1998 to December 31, 1998, these suspected patients presented with asymmetric hearing loss and/or tinnitus at the Department of Otolaryngology or Neurosurgery. ABRs were examined in 174 cases, the equilibrium tests, including caloric test, were in 300 cases, radiographic examinations were in 219 cases, speech audiometries were 104 cases, CT were in 304 cases and MRI were in 359 cases. Eighteen ANs (2.4% in suspected patients) were identified. Of 18 patients with AN, all eight AN patients examined had abnormal ABRs, i.e. no false negative case was revealed in ABR of the present study. Sensitivity and specificity of ABR were 100% and 88.6%, respectively. The sensitivities of CT and MRI were both 100%, whereas those of equilibrium test and radiographic examination were 66.7% and 85.7%, respectively. In the present study, the cost per AN diagnosed was 104, 700 points in the health insurance. Based on a 2.4% rate of AN identification, the cost of diagnosis would be 98, 244 points per neuroma if all suspected patients undergo only MRIs. If all 743 patients are examined with ABRs first and only those with abnormal ABRs (15.5%) receive MRIs, the cost would be 42, 888 points per AN. These results suggest that ABR is the most efficient and economical screening technique to select the cases for CT and/or MRI examinations to diagnose the AN, though we have to take a false negative in ABR into careful consideration.

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For the treatment of patients with Meniere's disease in the acute period, randomized controlled trials showed that anti-vertigo drugs, such as diphenidol and betahistine, are significantly effective. In the chronic period, Meniere's disease is specifically managed by osmotic diuretic, isosorbide. The dose comparative study showed that its opitimal dose is 90ml/day. Despite many controversies against endolymphatic sac surgery, including the Danish sham surgery study suggesting a placebo effect of mastoidectomy, the efficacy of the procedure is widely accepted. However, it is not clear that endolymphatic sac surgery alters the natural history of Meniere's disease in a long term.

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Patients with patulous Eustachian tube (ET) are bothered by the typical symptoms of severe fullness of the ear, autophony, respiratory tinnitus, etc. But the diagnosis was often regarded as stenosis of ET, and the symptoms were regarded as psychosomatic disorders due to the difficulty of diagnosis. Patulous ET was diagnosed by endoscopic video-monitor examination of the tympanic membrane and the pharyngeal orifice, sonotubometry, and the original questionnaire of the characteristic anamnesis. Among 224 patients with patulous ET, 208 patients were treated by therapeutic diagnosis of patulous ET; the cotton-tipped swab soaked in xylocain was inserted into the patulous pharyngeal orifice of the ET under the endoscopic technique. Closing the patulous ET, the bothersome symptoms such as severe fullness of the ear, autophony, and respiratory tinnitus dramatically disappeared and/or decreased, along with the additional symptoms such as stiffness of the neck and shoulder and many other equivocal complaints. It helps to relieve the anxiety troubling the minds of the patients. Furthermore, it is possible that a patient's patulous ET symptoms may be concealed by the retracted tympanic membrane and sensorineural hearing loss.
The therapeutic diagnosis of patulous ET through review of the clinicai cases clarified the clinical evidence of patulous ET, and the results were discussed.

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The effect of proinflammatory cytokines on spiral ligament (SL) fibrocytes was studied in secondary cell cultures. In one experiment, pneumococcal otitis media was induced in mice, and the levels of the two proinflammatory cytokines interleukin (IL)-1βand tumor necrosis factor (TNF)-α were measured in the middle ear effusion (MEE). Both cytokines were elevated 1 day after the inoculation of Streptococcus pneurnoniae into the middle ear cavity; IL -1βlevel decreased notably 3 days postinoculation. In a second experiment, cultures from murine SL fibrocytes were stimulated with IL -1β or TNF-α, at the approximate concentrations detected in the MEE, and the secretion of various mediators was measured. Levels of IL-6, soluble intercellular adhesion molecule-1, monocyte chemoattractant protein-1, macrophage inflammatory protein-2 were elevated after stimulation with TNF-α and IL-1β, but the elevations were significant after stimulation with TNF-α. Because the molecular weight of TNF-α is low enough for it to permeate through the round window membrane, we speculate that TNF-α in the MEE could affect the SL fibrocytes.

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Ginkgo Biloba Extract (EGB761) is a complex mixture of active ingredients prepared from the Ginkgo Biloba tree leaf and has a 24% content of flavonol heterosides and a 6% content of terpenes as ginkolides and bilobalides. EGB761 has been used in the treatment of patients with cardiovascular disorders and vertiginous diseases in European countries, and reported to improve cognitive function in geriatric patients. Previous studies have demonstrated that the administration of EGB761 improves vestibular compensation after VIII th nerve transection in the cat.
To investigate the neuropharmacological effect of EGB761 on the vestibular system, we perfused the vestibular nuclei of alert guinea pigs with EGB761 by the osmotic mini pump method and examined the postural changes by X-ray analysis. Perfusion consistently induced stereotyped reversible postural change that was the mirror image of that provoked by the unilateral lesion of the otolithical receptors. A control study using saline showed that postural change did not occur. These results support the hypothesis that EGB761 has a direct excitatory effect on lateral vestibular nuclei neurons and helps to explain the therapeutic effects of EGB761 on vertiginous disases.

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Otosurgery have been developed with an operative microscope which can give a totalview of the middle ear cavity.In the middle ear, however, there is the retrotympanic region where microscopic observation is difficult because of anatomical feature.This region includes the important structures, such as stapes, stapedial muscle, tympanic part of facial nerve, pyramidal eminence, tympanic sinus, and round window.It is very dangerous to perform otosurgery without adequate observation of these structures.
In order to perform a surgery safely with a full operative view, we introduced a rigid endoscope 4mm in diameter and 15cm in length with 0° and 30° angles of vision.The endoscopic-aided operation was performed in 53 ears for the last two years.With general anaesthesia, the endoscope was introduced into the tympanic cavity through a perforated or elevated tympanic membrane.
The endoscopic observation was monitored on TV screen and recorded in video.The endoscopic imagings were much more clean and widely expanded than those with a microscope with 25cm focus lens, because the endoscope can be introduced closely to a target within 5mm.They could show the detailed and bright views of microscopically invisible structure.
The disadvantages of the endoscope are that a surgeon has to hold the endoscope with his or her left hand and handle forceps or suction tube with the right, and to handle endoscope and surgical tools together in the narrow external canal.In 3 ears, the 4mm-diameter endoscope was difficult to insert in the canal and 3mm endoscope was substituted.Therefore, endoscopic guided ear operation needs some extent of expertise.
The endoscope, however, was very useful in otosurgery, especially to find residual cholesteatoma in tympanic sinus, under the ossicle or to avoid an injury of the facial nerve in stapedectomy.

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In three ears, middle ear surgery was performed with the aid of Er: YAG laser. This laser allowed the resection of the malleus head and incus body avoiding an inadvertent movement of the ossicular chain. In a case of sinus cholesteatoma, this laser facilitated the removal of the matrix together with the stapes superstructure. No vertigo or hearing loss was found during and after surgery. The Er: YAG laser seems to be a useful tool in middle ear surgery.

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We attempted to image the eustachian tube (ET) and its surrounding tissues by high-resolution computed tomography (HR-CT).Twenty-two normal subjects (44 ears) without middle ear problems were studied, and a patient with severe patulous ET was also studied as an abnormal case. In our device of multiplanar reconstruction technique, we were able to obtain the clear reconstructed images of the ET lumen as well as of its surrounding tissues (bone, ET cartilage, tensor veli palatini muscle, levator veli palatini muscle, Ostmann's fat tissue, tensor tympani muscle, internal carotid artery) at any desired portion, either parallel or perpendicular to the long axis of the ET. However, the exact borders between the ET cartilage and the muscles, Ostmann's fat tissue and the tubal gland were not clearly identified.In the severe case of patulous ET, the ET lumen was widely opened at each cross-sectional image from the pharyngeal orifice to the tympanic orifice, in contrast with its being closed at the cartilaginous portion in the normal cases.In addition, the fat tissue and glands around the ET lumen were not clearly identified in this case.We suggest that this method will lead to better understanding of the ET-related diseases such as patulous ET.

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The middle ear surgery with the use of fibrin glue has been commonly applied to the cases with an eardrum perforation, and we can attempt to apply the minimally invasive surgery with diseases in the ear including cholesteatoma. It is considered that middle ear surgery can be successfully performed even in a short stay in the hospital. But some patients have balance disorders after middle ear surgery even if they don't notice themselves. So we investigated body sway after middle ear surgery under local anesthesia by stabilometry. It was concluded as follows: 1) It is able to go home soon after simple myringoplasty. 2) Body sway was persisting about 2 hours after tympanoplasty.

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Twenty-one cases with primary cholesteatoma were treated in the past 12 years.
Primary cholesteatoma was diagnosed according to the following criteria.
1. No acquired chance of transplantation of epithelial cells in the middle ear structure.
2. No connection between the ear drum and the cholesteatoma.
The mean age with primary cholesteatoma included 6 males and 15 females was 9.8 years. The chief complaints of our patients were hearing loss in 12, otalgia in 5, and facial palsy in 2. In half of the patients, a white mass was seen through the ear drum. Pneumatization of the temporal bone was relativery good in 12 cases. The tympano-mastoid type of the primary cholesteatoma was seen in 19 and the petrous pyramid type in 2 patients. The patients with petrous pyramid type exhibited facial palsy.
During the surgery, the destruction of the ossiclular chain was observed mainly at the incudostapedial joint.
Cholesteatoma of the anterior tympanum was seen in only two cases.
The second stage operation was performed in 67% cases. An average hearing level was improved after the tympanoplasty surgery.
When we examine a child with hearing loss, we have to aware the existence of primary cholesteatoma.
However it is difficult to find a petrous pyramid type cholesteatoma in an early stage of the disease.

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There are several and various operative procedures for cholesteatoma, but postoperative problems sometimes occure as recurrence following residual cholesteatoma or postoperative retraction pocket. Our operative procedure is “Open & Closed method”, and we perform staged operation for residual cholesteatoma, and a new surgical approach by using the auricular cartilage for the attic reconstruction for recurrence of cholesteatoma of retraction pocket.
From May 1993 to April 1998 we performed tympanoplasty in 102 ears with fresh cholesteatoma and 36 cases of them underwent second-stage surgery (first stage operation→type III 15 ears & first stage operation→type IV 21 ears), 55 cases underwent single-stage surgery and 11 cases the first-stage alone. We investigated the 36 cases operated by staged tympanoplasty. Residual cholesteatomas were found in 13 cases (36%) at second stage operation and we removed residual cholesteatoma in all cases. After second stage operation there was no evidence of residual cholesteatoma, but in only one case showed recurrence following to retracion pocket.
Respectively the rate of success of hearing was 73% in first stage operation→type III, 81% in first stage operation→type IV and as a whole 78% in staged tympanoplasty.

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Hearing improvement after stapes surgery was investigated retrospectively on 41 ears undergone stapedotomy as an initial treatment by the author between April 1991 and March 1999.
They included otosclerosis (27 ears), congenital foot plate ankylosis (7 ears), stapes-facial canal fixation (3 ears), van der Hoeve syndrome (4 ears), stapes fixation with incus-stapes malformation (2 ears) and stapes fixation with malformation of inner ear (2 ears).
All of them present the stiffness curve hearing impairment in audiograms.
Shuknecht-type Teflon wire pistons (TWPs) were used in the stapes surgery. TWPs had all incus attachments except for two cases of incus-stapes malformation in which malleus attachments were used.
After the stapes surgery, both air and bone thresholds were significantly improved. However, three cases were not improved the hearing level as our expectation.
We also recommended the Skeeter drill for minimal invasive technique to fenestrate the foot plate and amputate the crus.

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A simple technique for closure of a tympanic perforation after tympanoplasty was used in six patients. This technique is characterized by inserting a small fragment of Terudermis^® into the perforation without fibrin glue.We attained successful closure in 5 patients out of 6.In this report, we showed this technique and discussed the details of our cases and results.

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A large cholesterol granuloma was found in the petrous apex by CT and MRI examination in a 14-yearold male. Cholesterol granulama was located surrounding the internal carotid artery, extending laterally and inferiorly. CT indicated the petrous apex lesion was connected to cholesterol granuloma in the middle ear via narrow route. As she had only a slight conductive hearing loss in the right ear, we developed a new transcanal-infrapetrosal approach to the petrous apex lesion in order to preserve the function of the inner ear. The advantages of this new approach were that it will be able to access to the infrapetrosal lesion easily and safely without injuring the internal carotid artery and to make a large communication route for drainage. Additionally, this approach must be very useful for patients with high jugular bulb which make it difficult to access the petrous apex lesion with infralabyrinthine approach.

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A 6-year-old girl was referred to our outpatient clinic for investigation of a conductive hearing impairment from birth on her left ear. She has no hereditary disease and her family showed no ear problem.
Her left tympanic membrane was normal, but a small yellowish mass was seen through the tympanic membrane in the middle ear. Audiogram showed that an averaged hearing level in the left ear was 57 dB with 40 dB air-bone gap and the right one was normal. CT showed the lesion was limited in the middle ear. Exploratory tympanotomy revealed that the mass included several pieces of hair, and the incus and stapes were missing, the round and oval windows were completely absent. After removal of the lesions, TORP was placed for ossicular reconstruction, but hearing improvement remained poor.
Teratoma limited in middle ear has been scarcely reported. Presence of teratoma and absence of the ossicle and inner ear window were thought to be associated developmentally.

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Paget's disease of the bone is a bone disorder characterized by rapid bone remodeling resulting in abnormal bone formations. This disease is common in Europe and North America, though it is rare in Japan. Furthermore, the disease is very uncommon in otholaryongology and only eight cases to date have been reported in Japan in a clear contrast to the field of orthopedic surgery.
A 52-year-old man with Paget's disease of polyostotic type received hemodialysis for chronic renal failure for 23 years. He had been treated his left external otitis for about two years. Left hearing loss, vertigo and left facial nerve palsy occurred during the cource of deterioration of left external otitis. Histopathological examination of his left temporal bone revealed Paget's disease. It was suggested that inflammation of the external auditory meatus expanded to the inner ear and the facial nerve resulted in the outcome, all of which may be closely linked to Pagetic bone changes in his left temporal bone and long-term hemodialysis.

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A 76-year-old male presented with pulsatile tinnitus in April 1998. Angiography revealed a dural arteriovenous fistula at the left transverse-sigmoid sinus fed by abnormal branches of the occipital artery. The distal portion of the left sigmoid sinus was occluded, thereby venous reflux consisted in the transverse sinus and the cortical veins. The patient has been known to have hypertrophic cardiomyopathy. We performed transvenous embolization of the involved left sigmoid and a part of the transvers sinus. The pulsatile tinnitus disappeared immediately and did not recur in four months following the treatment.
Our experience supports that the transvenous embolization is a safe, efficacious and useful method for a poor risk case. Preoperative angiography is recommended for predicting the risk of critical complications of the dural arteriovenous fistula.

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A 8-year-old girl presented with a hearing loss in her left ear. Pure tone audiometry showed sensorinural hearing loss, and her hearing level became worse more than 40 dB for about 2 months. X-ray examination showed enlargement of the left internal auditory meatus, and MRI demonstrated a large mass (about 4 cm) at the left cerebello-pontine angle. Speech discrimination was 85%, with Jerger's type III in Bekesy audiometry, and no response was found in caroric test in the left ear. Only the first wave responce was noted in auditory brain responce. She was operated on by suboccipital approach and histological examination confirmed that it was neuroma. Her hearing was not preserved, but the facial nerve function was preserved.

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