Virtual endoscopy imaging of the middle ear cavity and ossicles.

Ten cadaver temporal bone blocks were studied with high-resolution computed tomography (HRCT) in order to produce topographic images, which are more informative than ordinary CT slices. Virtual endoscopic images were produced with separate, commercially available software, paying attention to the middle ear cavity and ossicles. Four major viewing locations for virtual endoscopy (the ear canal, hypotympanum, attic and eustachian tube) developed images acceptably. The malleus and incus were visualized properly. Small structures such as the lenticular process and the stapes sometimes failed to have good imaging. The eustachian tube and attic virtual views, which are usually not receptive to ordinary endoscopy, gave proper visualization of middle ear structures. Even the smallest structure, the stapes, can produce a virtual image.Virtual endoscopic images, or topographic images, of the middle ear and ossicles contribute to the understanding of the anatomy of the middle ear, thus enhancing the chances for successful surgery.

Comparison of CT and fiberoptic video-endoscopy findings in congenital dysplasia of the external and middle ear.

Twenty-six ears (of 25 patients) with congenital dysplasia of the external and middle ear were studied with two different types of imaging technologies in order to find out if it is possible to improve the anatomical overview of the dysplastic middle ears by combining the imaging methods. All the 26 ears were studied with computed tomography (CT), which gave cross-sectional images of the tympanic cavity. A fiberoptic video-endoscope (FVE) was introduced through the nose and via the Eustachian tube into the middle ear so that the topographic view of the anatomical structures of the middle ear could be visualized. Some structures were visualized better with FVE than with CT and vice versa. We concluded that the combined information obtained from these two imaging technologies provided a better understanding of the structural anatomy of a congenital dysplastic middle ear.

Endoscope-guided round window fistula repair.

OBJECTIVE: Endoscope-guided round window membrane repair was performed to evaluate whether the approach is feasible in the treatment of a round window fistula. STUDY DESIGN: Retrospective case review. SETTING: Tertiary care academic center. PATIENT: A 27-year-old man had been scuba diving 6 days previously in the Australian Great Barrier Reefs. He had poor hearing with tinnitus in the left ear and a vertiginous sensation. INTERVENTION: A myringotomy was incised, and a tympanoscope was introduced into the middle ear cavity. With the patient under general anesthesia, the middle ear and the oval and round window areas were examined with a tympanoscope. In endoscopic visualization, a round perforation could be seen in the round window membrane. After detection of the round window perforation, a small piece of temporal fascia was obtained to seal the membrane perforation. RESULTS: One month after the operation, the patient's hearing was significantly better. The myringotomy had healed. CONCLUSION: A transmyringeal endoscopic procedure for round window fistula repair is feasible and combines the best features of minimally invasive surgery and aural endoscopy.

Tympanoscope-assisted myringoplasty.

Thirty ears of 29 patients with different sized perforation of the tympanic membrane were operated on with the aid of rigid otoendoscopes. The technique has a significant novel feature: endoscopy of the tympanic cavity through a perforation with small tympanoscopes 1.7 mm in diameter with a 0%. The postoperative air-bone gap was less than 10 dB in 90% of the ears. It was concluded that tympanoscope-assisted myringoplasty is a reliable and simple procedure with the benefit of minimal trauma in healthy tissue and that it is a feasible approach for day-case surgery with an ordinary success rate of tympanic membrane closure and hearing results.

Visualization of the middle ear with high resolution computed tomography and superfine fiberoptic videomicroendoscopy.

Ten temporal bone blocks were dissected from fresh postmortem specimens from patients succumbing to diseases unrelated to the ears. A superfine fiberoptic videomicroendoscope (SFV) was introduced through the eustachian tube into the middle ear, and middle ear structures were visualized. The cadaver temporal bone blocks were also studied with high-resolution computed tomography (HRCT). When HRCT gave good results SFV did not succeed well and vice versa. However, SFV provided topographic anatomical information of the middle ear structures while HRCT gave cross-sectional images of the anatomy of the tympanic cavity. The different types of information obtained by the two imaging technologies supplement each other and were found to improve diagnosis in such cases as external ear canal atresia.

Tympanoscopy to increase the accuracy of diagnosis in conductive hearing loss.

The diagnosis of conductive hearing loss is usually based on audiological methods and radiology. The aim of our study was to show that there is a useful additive method to clarify the findings of diseases with conductive hearing loss. Patients (151 ears) with conductive hearing loss were examined using several methods: otomicroscopy, air- and bone-conduction threshold,pure tone average, speech threshold, speech discrimination, tympanometry and stapedial reflex and tympanoscopy. The management of the patients changed in 17 per cent of cases due to tympanoscopy. In a group with normal tympanic membrane the movement of the stapes during endoscopy was compared to stapedial reflex. Stiff stapes were found more often than an abnormal stapedial reflex. Middle ear endoscopy can increase the accuracy of diagnosis of conductive hearing loss thus enhancing decision making in the case of the patient.

Middle ear imaging via the eustachian tube with a superfine fiberoptic videomicroendoscope.

The aim of this study was to systemically evaluate the visualization of the middle ear structures with a superfine fiberoptic videomicroendoscope introduced via the eustachian tube. With the permission of the Finnish Ministry of Health ten temporal bone blocks were dissected from lately succumbed patients. An Olympus AF-8 (0.8 mm outer diameter) angiofiberscope was used. The AF-8 fiberoptic videomicroendoscope is a straightforward-looking endoscope with a 55 degrees field of view. The endoscope tip was introduced through the eustachian tube into the middle ear and the middle ear structures were visualized and counted. Forty-three anatomical structures were listed and the results presented in a categorized table. Nineteen anatomical objects among 43 were never observed in any temporal bone block. The rest of the anatomical structures were visualized to varying degrees.

Endoscopy and otomicroscopy in the estimation of middle ear structures.

In order to study the variation within and between endoscopy and otomicroscopy a Gage repeatability and reproducibility design was created, with which the middle ears were studied of eight cadaver temporal bone blocks through the ear canal three times in random order using both methods. A Zeiss OPMT-1 operating microscope and Olympus endoscopes were used. The data were analysed in accordance with the analysis of variance principle, where the total variation was divided into different components. The anatomical areas were counted and registered via quadrants. There was a distinct difference between the results of the two methods in favour of the endoscopes. Furthermore, the variation between the methods and between the trials was analogous.

Endoscopy of the middle ear structures.

The anatomical structures of the middle ear cleft were investigated with endoscopes of angle of view of 0 degree , 3 degrees and 90 degrees (1.7 mm in diameter). Temporal bone blocks donated by lately succumbed patients were studied 3 times in random order. Forty-three anatomical structures of the middle ear cleft were chosen for inspection. The anatomical structures were counted and registered alternately at the time of endoscopy through 4 quadrants of the tympanic membrane. The study included 12,384 observation pieces. The results are presented in tables. The most suitable quadrant of the tympanic membrane and the angle of endoscope for optimal visualization are presented. The visualization is also presented by anatomical structure and by quadrants of the tympanic membrane. The authors' opinion for selection of the most convenient quadrant of the tympanic membrane and suitable angle of endoscope is presented. The majority of the anatomical structures could be visualized with either a 30 degrees or 90 degrees endoscope. There were difficulties in observing the neck of the malleus, the head of the malleus and the lateral semicircular canal. There was no benefit from the use of a 0 degree angled endoscope in the visualization of the middle ear structures.