[Direct observation of the tympanic cavity by the superfine fiberscope]

Transeustachian Middle Ear Endoscopy Using a Steerable Distal-Camera Tipped Endoscope

OBJECTIVE

Demonstrate the ability of a novel steerable distal chip endoscope to traverse the Eustachian tube and provide diagnostic quality images of the human middle ear.

PATIENTS

Three cadaveric temporal bone specimens were used in this work.

INTERVENTION

Diagnostic transeustachian endoscopy of the middle ear was performed.

MAIN OUTCOME MEASURE

Diagnostic image quality.

RESULTS

A novel 1.62 mm steerable endoscope successfully cannulated the Eustachian tube of three human cadaveric temporal bone specimens to reveal intact middle ear anatomy with high optical clarity.

CONCLUSIONS

A steerable endoscope can be designed to traverse the human Eustachian tube and provide diagnostic quality images of middle ear anatomy.

Video endoscopy-assisted vestibular neurectomy: a new approach to the eighth cranial nerve

Disequilibrium, ranging from lightheadedness to severe vertigo, is frequently of great concern to the patients with a variety of inner ear diseases, and may cause occupational and social disability. Vestibular nerve section may be considered when vestibular symptoms are resistant to medical therapy and associated with serviceable hearing in the involved ear. During the last century, numerous authors described several routes for intracranial section of the eighth nerve, such as lateral suboccipital craniotomy, middle cranial fossa approach, and retrolabyrinthine approach to the vestibular fossa. Control of vertigo by all routes to the vestibular nerve has a success rate of 80% to 90%. The potential for endoscopic approach to intracranial cavities was recognized early in this century but, due to technical limitations, was largely abandoned after a few attempts. Advances in optics, and the introduction of very fine instruments made endoscopy worth reconsideration. Since the early 1980s, rigid endoscopes have been used in otorhinolaryngology for paranasal sinus surgery and the visualization of the facial and vestibulocochlear nerves during acoustic tumor surgery. We performed endoscopic section of the vestibular nerve through a retrolabyrinthine approach in two cadavers and in two patients with the symptoms of disequilibrium. In the literature survey, we could find no reports on vestibular neurectomy performed by endoscopic technique. We describe technical details of the approach, and conclude that the technique is safe and effective.

[Mini-endoscopy in the head and neck region]

Minimally invasive, in particular endoscopic treatment modalities are an important topic in medicine today. Over the last 15 years mini-endoscopy (ME) has been introduced and established in different fields of the head and neck region. ME includes endoscopy of the Eustachian tube, middle ear, lacrimal duct system and duct system of the major salivary glands. Direct visualization by endoscopy enables rapid, efficient and accurate diagnosis and treatment planning according to the findings. In the majority of cases simultaneous interventional therapy is possible. This has lead to a fundamental change in treatment regimes which now aim to preserve the anatomic structure and function. In specialized centers the frequency of external dacryocystostomy could be reduced to less than 10% by means of endoscopic surgery of the lacrimal system, while the frequency of parotidectomy was reduced to below 5%. This development allows not only for medical advances, but also for the desired cost reduction on the part of the administrative organs responsible for providing medical care.

Eustachian Tube Function and the Middle Ear

Eustachian tube dysfunction has been linked to causing middle ear pathology. One of the sequelae seen is tympanic membrane retraction. Concern occurs when this physiological state becomes chronic, leading to adhesive otitis media followed by debris collection and fulminate cholesteatoma. This chapter explores the role the eustachian tube plays in regulating middle ear and mastoid aeration, the causes of eustachian tube dysfunction, and the treatment of this disorder.

Virtual endoscopy of the tympanic cavity based on high-resolution multislice computed tomographic data

OBJECTIVE

This study was designed to assess the value of high-resolution multislice computed tomography (MSCT) data of the petrous bone for the virtual endoscopic visualization of the tympanic cavity.

BACKGROUND

The recently introduced MSCT technology has improved spatial resolution in the z axis as well as scan speed in computed tomography. Three-dimensional rendering of high-resolution MSCT data of the petrous bone may be expected to provide endoluminal views of superior image quality, thus competing with transtympanic endoscopy (otoendoscopy).

SETTING

This study was conducted at a university teaching hospital.

MATERIALS AND METHODS

Cadaveric phantom studies in a MSCT scanner were performed to define a data acquisition protocol, combining adequate detail resolution with low tube current. Subsequently, the cadaveric phantom underwent otoendoscopy. The postprocessing parameters of the three-dimensional rendering protocol were chosen to produce views closely resembling the corresponding otoendoscopic images. High-resolution data from 18 patients with pathologic conditions of the middle ear, as suggested by clinical findings and assessment of cross-sectional data, were postprocessed using the volume rendering technique to generate standardized virtual endoscopic views. A total of 36 virtual endoscopic scans of the tympanic cavity were generated.

RESULTS

With regard to intermediate and high-density structures, virtual endoscopic images, based on MSCT data, yielded endoluminal views closely resembling corresponding otoendoscopic views. Virtual endoscopy seems useful for imaging ossicular pathologic conditions such as dysplasia and chain disruption as well as for assessing patient status before and after otosurgery.

CONCLUSION

MSCT data sets allow for generating virtual endoscopic views closely resembling otoendoscopic images. The technique is especially useful when ossicular pathologic changes are present as well as for preoperative and postoperative imaging of otologic procedures.

Analysis of the dysfunctional eustachian tube by video endoscopy

OBJECTIVE

Human eustachian tubes with known pathologic conditions of the ear were inspected endoscopically, and video recordings were made for slow-motion analysis of the pathophysiologic changes.

SETTING

Ambulatory office in a tertiary referral center.

SUBJECTS

Forty-four adults with 64 ears having pathologic conditions.

INTERVENTIONS

Transnasal endoscopic examination of the nasopharyngeal opening of the eustachian tube during rest, swallowing, and yawning to study the dilatory movements of the eustachian tube.

MAIN OUTCOME MEASURES

Slow-motion video analysis of the dilatory movements of the eustachian tube.

RESULTS

Sixty-four ears and eustachian tubes with pathologic changes were studied. Tubal function was graded on (1) the extent of lateral excursion and progression of dilatory wave as estimates of tensor veli palatini and dilator tube muscle function, reduced function being observed in 43 tubes; (2) the degree of mucosal disease, which was significant in 48 tubes; (3) obstructive mucosal changes, which were present in 15 tubes; (4) ease and frequency of tubal dilation with maneuvers-26 tubes opened moderately, 21 opened minimally, and 11 were unable to open; and (5) patulous tubes-all 6 clinically patulous tubes showed concavities in the superior third of the tube, which is convex in normal subjects. All tubes with active pathologic conditions of the ear (otitis media with effusion, tympanic membrane retraction, draining ear, cholesteatoma) had significant abnormalities. A correlation could not be made between the severity of middle ear disease and the severity of observed eustachian tube dysfunction.

CONCLUSIONS

Slow-motion endoscopic video analysis is a potentially useful technique in classifying types of pathologic changes in the eustachian tube. Additional studies of dysfunctional tubes are needed to predict outcomes in operative ear cases and to design intratubal therapy for chronically dysfunctional tubes.