Perilymph fistula--a diagnostic dilemma

Detection of perilymphatic fistula in labyrinthine windows by virtual endoscopy and variation of reconstruction thresholds on CT scan

Background: Perilymphatic fistula (PLF) is a breach in a labyrinthine window. The opening might decrease the radiological density of the window.Aims/objectives: To evaluate the radiological density of the labyrinthine windows by virtual endoscopy on CT scan.Materials and methods: This prospective study included 47 adult patients with PLF and 98 control patients. Diagnosis of PLF was based on a composite radio clinical score and/or intra operative visualization of the fistula and/or resolution of the symptoms after surgery. On routine CT-scan, labyrinthine windows were examined by virtual endoscopy. The reconstruction threshold was gradually increased until a virtual opening appeared (opening threshold [OT]) and compared to the contralateral window (OT difference).Results: The OT difference was higher in patients than in controls (60.2 ± 10.36 (SEM), n = 47 versus 28.0 ± 2.29 Hounsfield units (HUs), n = 98, p < .01 unpaired t-test). A ROC analysis showed that at an OT difference of 31.5 UH had a sensitivity of 75% and a specificity of 75% for the PLF diagnosis.Conclusions: CT-scan virtual endoscopy and threshold variation provided high specificity and sensitivity in the PLF diagnosis.Significance: This post processing of radiological data appears to enhance the diagnostic value of CT scan.

Inner ear barotrauma in divers: an evidence-based tool for evaluation and treatment

OBJECTIVE

To systematically search the literature for studies evaluating the typical presentation and testing that is performed for divers with inner ear symptoms and then to create a tool for clinicians when evaluating a diver with inner ear symptoms.

METHODS

Nine databases, including PubMed/MEDLINE were systematically searched through 31 January 2018. The PRISMA statement was followed.

RESULTS

Three-hundred and two manuscripts were screened, 69 were downloaded and 21 met criteria to be included in this review. The articles were evaluated for symptomatic trends and initial evaluation work-up primarily focusing on inner-ear barotrauma (IEBt) and inner ear decompression sickness (inner ear DCS). The trends for IEBt were compared to typical inner ear DCS presentation based on large study inner ear DCS results consistent with the plethora of research available. Finally, the HOOYAH Tool was developed to assist the receiving provider to better determine the most likely diagnosis and thus initiate appropriate treatment. The HOOYAH Tool is comprised of the following: 1) H: hard to clear; 2) O: onset of symptoms; 3) O: otoscopic exam; 4) Y: your dive profile; 5) A: additional symptoms and 6) H: hearing. For each of these components, the typical presentation is described allowing the provider better to discern the correct diagnosis.

CONCLUSION

The diagnosis of IEBt remains difficult to define short of visualization through surgical exploration. Early treatment is defined by conservative management with a subsequent observational period to determine symptomatic resolution and need for surgery. However, a similar differential diagnosis is inner ear DCS which requires early recompression. The HOOYAH tool provides a method for assisting the provider in forming a more confident decision regarding the underlying pathology and facilitation of the appropriate treatment.

X-ray microtomography study of otic capsule deficiencies: three-dimensional modelling of the fissula ante fenestram

BACKGROUND

The postulated sites of perilymph fistulae involve otic capsule deficiencies, in particular, at the fissula ante fenestram. Histological studies have revealed this to be a channel extending from the middle ear, and becoming continuous with the inner ear medial to the anterior limit of the oval window. The relationship between a patent fissula and symptoms of perilymph fistula is contentious.

OBJECTIVE

The understanding of the anatomy of the fissula ante fenestram is incomplete. Histopathology is inherently destructive to the delicate ultrastructure of the middle and inner ear. Conversely, X-ray microtomography allows non-destructive examination of the otic capsule. In this study, we used X-ray microtomography to characterise the fissula ante fenestram.

MATERIALS AND METHODS

We imaged cadaveric temporal bones with X-ray microtomography. We used the Avizo Fire (Visualization Science Group, Merignac Cedex, France) software to perform post-processing and image analysis.

RESULTS

Three-dimensional modelling of the fissula ante fenestram allowed stratification into four forms: rudimentary pit; partial fissula; complete occluded fissula; and complete patent fissula.

CONCLUSION

X-ray microtomography showed that the fissula ante fenestram is present in various forms from rudimentary pit to complete deficiency of the otic capsule. This understanding may have implications for otologic surgery and clinical diagnosis of perilymph fistula.

Critical evaluation of round window membrane sealing in the treatment of idiopathic sudden unilateral hearing loss

Objectives

Rupture of the round window membrane with consecutive development of a perilymphatic fistula (PLF) is still a matter of controversial debate in the pathogenesis of idiopathic sudden sensorineural hearing loss (SSHL). Until now no consensus exists about whether these patients benefit from performing an exploratory tympanotomy with sealing of the round window. The aim of the present study was to analyze critically the effectiveness of sealing the round window membrane in patients with SSHL.

Methods

The clinical data of 51 patients with SSHL and a mean hearing decline of at least 60 dB over 5 frequencies who were treated with tympanotomy and sealing of the round window membrane were retrospectively analyzed. The results have been compared to the current state of the literature.

Results

Intraoperatively a round window membrane rupture or fluid leak was observed in none of the patients. After performing tympanotomy the mean improvement of hearing level was 32.7 dB. Twenty of 51 examined patients (39.2%) showed a mean improvement of the hearing level of more than 30 dB and a complete remission could be detected in 12 patients (23.5%). Reviewing the literature revealed no standard guidelines for definition or treatment of SSHL as well as for evaluation of hearing loss and its recovery.

Conclusion

The results of the present study and the literature should be discussed critically. It is unclear whether tympanotomy and sealing of the round window membrane may be a meaningful treatment for SSHL. Therefore this procedure should be discussed as a therapeutic option only in selected patients with sudden deafness or profound hearing loss in which PLF is strongly suspicious or conservative treatment failed.

Perilymphatic fistula of the round window

OBJECTIVE

To highlight diagnostic and treatment pitfalls in perilymphatic fistula.

CASE REPORTS

Two cases of round-window fistula are reported, detailing clinical aspect, treatment and outcome. The triad comprising sensorineural hearing loss, tinnitus and vertigo with associated fistula sign is classical but in fact rarely encountered. Imaging is of limited contribution, but may reveal anatomic abnormalities suggestive of perilymphatic fistula. Outcome is improved by early management, especially in case of moderate hearing loss.

DISCUSSION/CONCLUSION

Diagnosis of perilymphatic fistula is challenging, but enables effective treatment. On any suspicion, surgical exploration should be undertaken, being the only reliable guide to diagnosis and etiologically adapted management.

Results of Exploratory Tympanotomy following Sudden Unilateral Deafness and its Effects on Hearing Restoration

In cases of acute unilateral deafness, no consensus exists as to whether tympanotomy and sealing of the round window should be performed routinely. To further address this issue, we conducted a retrospective study of pre-, intra-, and postoperative findings in 97 patients who had undergone exploratory tympanotomy (EXT) after the onset of sudden and severe unilateral deafness. Our goal was to ascertain, if we could, whether the benefits of EXT outweigh the risks. We also took into account the effects of perilymph fistula (PLF) on the etiology of sudden hearing loss and postoperative outcomes. We found that routine EXT was indeed beneficial for these patients. It was associated with a very low surgical complication rate, and its effects on hearing as assessed by objective measures were beneficial. The greatest benefits were seen in patients who underwent EXT within 7 days after the onset of their hearing loss. With respect to PLF, we found that the presence or absence of the “typical history” of PLF (i.e., a sudden unilateral hearing loss within 48 hours after a precipitating trauma or physical exertion) had no bearing on whether a PLF was actually present in our group; nor was vertigo a reliable predictor of PLF. We recommend that EXT be performed on all patients with new-onset acute unilateral deafness, barring any contraindications, of course. The absence of a typical history of PLF should not dissuade the surgeon from proceeding with EXT.

[Exploratory tympanotomy for suspected traumatic perilymphatic fistula]

Firstly reported after stapedectomy, perilymph fistula (PLF), may occur due to trauma.

AIM

Preoperative symptoms and therapeutic results are described and analyzed after exploratory tympanotomy for traumatic PLF.

MATERIAL AND METHODS

Traumatic PLF was investigated in 90 patients (97 examinations) by exploratory tympanotomy at the Nantes University Hospital from 1995 to 1999. Preoperative symptoms were recorded and compared to results of tympanotomy to determine their diagnostic value. Similarly post-operative recovery was compared to results of tympanotomy.

RESULTS

This study showed the value of two symptoms: aural fullness and balance disturbance. During each surgical procedure, systematic grafting was performed even if fistulization was unapparent. The best results were achieved for vestibular symptoms and concerned more vertigo than auditory symptoms. There was no significant difference in postoperative symptoms, between patients with a leak and patients without a leak.

CONCLUSION

This demonstrates that the oval and round window should be grafted with connective tissue when an exploratory tympanotomy is performed.

Perilymphatic fistula

A perilymph fistula is an abnormal connection between the inner and middle ear that allows escape of perilymph fluid into the middle ear compartment. The clinical symptomatology that follows leakage of fluid is by and large indistinguishable from a number of other pathologies that affect inner ear function. Definite diagnostic proof of a perilymph fistula remains elusive, and methods of diagnosis remain controversial. Traumatic tears in the oval or round windows remain a major cause of perilymph fistula, yet an index of suspicion in traumatic brain injury frequently remains low. The diagnosis of perilymph fistula must always be considered in the appropriate clinical setting of head trauma, barotrauma, and in patients with unresolved and undiagnosed episodes of recurrent vertigo or hearing loss. Surgical treatment with patching of oval and round windows remains the mainstay of therapy for this condition.

An unusual case of presumed perilymph fistula

Perilymph fistulae have been described for over 30 years and yet there are no universally accepted diagnostic criteria or treatment regimes for them. This paper describes an unusual case of a presumed traumatic perilymph fistula and discusses its treatment and prognosis in relation to previous studies.

Sudden sensorineural hearing loss after general anesthesia for nonotologic surgery

Sudden sensorineural hearing loss (SNHL) is a well-recognized phenomenon that is attributed to a variety of etiologies. Sudden SNHL after cardiopulmonary bypass surgery has been well reported and is thought to be due to microemboli. However, a review of the English literature revealed only 15 cases of SNHL after general anesthesia for nonotologic surgery. Several etiologies for this loss have been suggested, but no proven pathogenesis is yet available. This report adds to the literature three additional cases of sudden SNHL after general anesthesia for nonotologic surgery. The literature is reviewed and proposed mechanisms of injury are discussed.