Bone conduction hearing in the Guinea pig and the effect of artificially induced middle ear lesions.

Although human bone conduction (BC) hearing is well investigated, there is a lack of information about BC hearing in most other species. In humans, the amount of conductive loss is estimated as the difference between the air conduction (AC) and BC thresholds. Similar estimations for animals are difficult since in most species, the normal BC hearing thresholds have not been established. In the current study, the normal BC thresholds in the frequency range between 2 kHz and 20 kHz are investigated for the Guinea pig. Also, the effect of a middle ear lesion, here modelled by severing the ossicles (ossicular discontinuity) and gluing the ossicles to the bone (otosclerosis), is investigated for both AC and BC. The hearing thresholds in the Guinea pigs were estimated by a regression of the amplitude of the compound action potential (CAP) with stimulation level and was found robust and gave a high resolution of the threshold level. The reference for the BC thresholds was the cochlear promontory bone velocity. This reference enables comparison of BC hearing in animals, both intra and inter species, which is independent on the vibrator and stimulation position. The vibration was measured in three orthogonal directions where the dominating vibration directions was in line with the stimulation direction, here the ventral direction. The BC thresholds lay between -10 and 3 dB re 1 µm/s. The slopes of CAP growth function were similar for AC and BC at low and high frequencies, but slightly lower for BC than AC at frequencies between 8 and 16 kHz. This was attributed to differences in the stimulus levels used for the slope estimation and not a real difference in CAP slopes between the stimulation modalities. Two kinds of middle ear lesions, ossicular discontinuity and stapes glued to the surrounding bone, gave threshold shifts of between 23 and 53 dB for AC while it was below 16 dB when the stimulation was by BC. Statistically different threshold shifts between the two types of lesions were found where the AC threshold shifts for a glued stapes at 2 and 4 kHz were 9-18 dB greater than for a severed ossicular chain, and the BC threshold shifts for a glued stapes at 4 and 12 kHz were 8-9 dB greater than for a severed ossicular chain.

Pneumolabyrinth and Recurrent Paroxysmal Positional Vertigo After Traumatic Stapes Fracture.

OBJECTIVES:: The development of pneumolabyrinth without previous head trauma is a rare event; the associated symptoms may be nonspecific, and they can simulate various cochleo-vestibular pathological entities. The aim of the present study is to describe one of these rare occurrences, characterized by a peculiar onset. METHODS:: We report a case of stapes fracture secondary to ear pick penetration into the middle ear with a pneumolabyrinth that caused a recurrent paroxysmal positional vertigo (PPV) mimicking a canalolithiasis. RESULTS:: The patient developed a profound left sensorineural hearing loss and an intractable PPV with "migrant" features. A pneumolabyrinth was visualized with high-resolution computed tomography. A perilymphatic fistula (PLF) with stapes fracture was found while performing an explorative tympanotomy. After the surgical treatment of the PLF, the patient no longer complained of vestibular symptoms. CONCLUSIONS:: To our knowledge, this is the fifth case of traumatic pneumolabyrinth simulating a canalolithiasis without previous history of temporal bone trauma and/or middle ear surgery. A pneumolabyrinth should be suspected in case of patients presenting recurrent intractable PPV after ear trauma.

Tympanometry and isolated fracture of the stapes.

INTRODUCTION: Temporal bone fractures are frequently associated with ossicular dislocations or fractures, most commonly involving the incus. To our knowledge, isolated fracture of the posterior crus of the stapes has not been previously reported. CASE REPORT: A 20-year-old man consulted for persistent left hypoacusis several months after a head injury. Initial computed tomography of the temporal bone showed a simple temporal bone fracture with no other associated abnormalities. The diagnosis of stapes fracture was suggested by increased compliance on tympanometry, leading to a second thin-section temporal bone computed tomography, which suggested a fracture of the posterior crus of the stapes. Endaural surgical exploration confirmed the diagnosis and allowed placement of ionomer cement in the posterior crus. DISCUSSION: The possibility of ossicular dislocation or fracture must be considered in patients with persistent conductive hearing loss associated with increased compliance on tympanometry, even when computed tomography of the temporal bone does not show dislocation of the ossicular chain or ossicular fracture. Hearing rehabilitation can be performed by hearing aid or surgical reconstruction of the ossicles.

Treatment of traumatic stapediovestibular luxation: case report with the introduction of a new technique and review of literature.

OBJECTIVE: Stapediovestibular luxations are rare lesions that are most commonly caused by direct, penetrating trauma to the external ear canal. In this type of ossicular dislocation, disruption of the annular ligament or footplate fracture may lead to a perilymphatic fistula (PLF) presenting with cochleovestibular symptoms including (progressive) sensorineural hearing loss, tinnitus, and vestibular symptoms. The objective of this article is to define the optimal treatment of stapediovestibular luxations and review the literature on this topic. PATIENT: We present a case of internal stapediovestibular dislocation and pneumolabyrinth after penetrating trauma with predominantly conductive hearing loss and incapacitating vertigo. INTERVENTION: Middle ear inspection with removal of the luxated incus, repositioning of the stapes with a "stapedial strut" and closure of the tympanic membrane. MAIN OUTCOME MEASURES: Hearing outcome and vestibular symptoms of this patient are presented, and all comparable cases in the literature are reviewed. RESULTS: Complete resolution of the vestibular symptoms and stabilization of the bone conduction thresholds. CONCLUSION: In patients with pneumolabyrinth after middle ear trauma with mild symptoms, we recommend initial conservative treatment with close monitoring of hearing. In patients with severe, persisting, or progressive vestibulocochlear symptoms, exploratory tympanotomy should be performed to check for and treat PLF. Oval window fistula repair is reported to have variable hearing outcomes but offers complete resolution of vestibular symptoms in most cases. The stapedial strut is one of the possible surgical techniques in case of an internally luxated stapes.

Late pneumolabyrinth after undiagnosed post-traumatic perilymphatic fistula. Case report illustrating the importance of systematic emergency management.

INTRODUCTION: Temporal bone fracture is a common complication of high-energy cranial trauma. Labyrinth involvement is rare, but there is a risk of perilymphatic rupture that is often underestimated on initial clinical examination due to the predominance of neurological and/or somatic symptoms. CASE REPORT: A patient presented with overlooked perilymphatic fistula, decompensated by hyperpressure effort due to poorly adapted management. DISCUSSION: Following a review of the literature on post-traumatic pneumolabyrinth, overall management (from diagnosis to treatment, via prevention advice) was analyzed. A constructive critique of the patient's treatment was thus made. CONCLUSION: We argue for a systematic management protocol in cranial trauma with temporal bone fracture, comprising ENT examination, millimetric-scale cross-sectional imaging of the fracture site, and standardized counseling to prevent late complications.

Hearing loss in Paget's disease: a temporal bone histopathology study.

BACKGROUND: Hearing loss in Paget's disease of bone (PDB) is typically mixed and bilateral. Although different mechanisms have been proposed, the pathophysiology of hearing impairment remains unclear. OBJECTIVE: The purpose of this study is to describe the histopathologic findings of temporal bones in patients with PDB and elucidate possible pathologic mechanisms related to hearing impairment. METHODS: This is an archival human temporal bone study of 8 subjects diagnosed with Paget's disease from the temporal bone collection of the UCL Ear Institute. RESULTS: A fractured stapes footplate was observed in 1 temporal bone and stapes footplate fixation in 2 other specimens. Obliteration of Cotugno's canal by extensive bone remodeling was observed in 78% of temporal bones. An intracochlear vestibular schwannoma was observed in 1 specimen (previously reported in the literature). Other findings include microfissures and microfractures of the otic capsule, bleeding in the scalae, strial atrophy, and cystic lesions in the spiral ligament. CONCLUSION: This study is the first to report a fractured stapes footplate, as a causative lesion of conductive hearing loss in PDB. Extensive bone remodeling around Cotugno canal also was a frequent finding, not reported before in the literature. We hypothesize that sensorineural hearing loss in patients with PDB of the temporal bone may, in some cases, be attributed to obliteration of Cotugno's canal by remodeling pagetoid bone, thus obstructing the venous drainage of the cochlea, with a subsequent effect on the function of stria vascularis and spiral ligament. This seems to be consistent with experimental studies in animals.

Traumatic pneumolabyrinth: air location and hearing outcome.

OBJECTIVE: To describe 3 cases of pneumolabyrinth after penetrating injury to the middle ear and to review previously reported cases, comparing precipitating factors and hearing outcomes. DATA SOURCES: Three cases we encountered and the PubMed and Japan Medical Abstracts Society databases. STUDY SELECTIONS: In addition to our 3 cases, we identified 48 cases from 41 articles regarding pneumolabyrinth. DATA EXTRACTIONS: All articles describing cases of pneumolabyrinth were used for this review. DATA SYNTHESIS: Among the 51 cases, audiologic evaluation was not available in 16 cases. In the remaining 35 cases, hearing outcomes were analyzed focusing on 3 factors: 1) differences in and interval until medical intervention, 2) existence of stapes lesions, and 3) extension of air bubble into the inner ear. We failed to find any significant differences in interventions, although operation less than 2 weeks after injury tended to be associated with a higher rate of hearing recovery (54%) than operation 2 weeks or longer after injury (25%). Furthermore, 11 (48%) of 23 cases with pneumolabyrinth limited to the vestibule or semicircular canals showed improved hearing, whereas none of 6 cases (0%) with pneumolabyrinth extending from the vestibular organs to the cochlea showed hearing recovery. This difference was statistically significant (p < 0.05). CONCLUSION: Assessment of the location and extension of pneumolabyrinth appears important in predicting hearing outcomes and planning the management of middle and inner ear trauma.

Traumatic dislocation of the incudostapedial joint repaired with fibrin tissue adhesive.

We present a case of traumatic dislocation of the incudostapedial joint (ISJ) and a simple method for controlled application of the glue using commercial fibrin tissue adhesive. A 26-year-old female presented to our ENT clinic for hearing impairment to her left ear 2 months after a head trauma due to a motorcycle accident. The audiogram revealed a 40- to 50-dB HL conductive hearing loss with a notch configuration in bone conduction curve on the left ear. Computed tomography of the left temporal bone revealed a longitudinal fracture line. An exploratory tympanotomy was performed under general anesthesia. The ISJ was found dislocated while the incus was trapped by the edges of the bony lateral attic wall fracture. A small bony edge that impeded incus movement was removed and a small amount of the glue was precisely applied to the lenticular process of the incus with an angled incision knife. The long process of the incus was firmly pressed over the stapes for 30 seconds with a 90° hook and 60 seconds after the application of the glue the ISJ was repaired. One year after our patient achieved full airbone gap (ABG) closure (ABG, ≤10 dB HL), while she demonstrated overclosure in frequencies 2 and 4 kHz. Fibrin tissue glue allowed safe, rapid, and accurate repair of the ISJ and resulted in an anatomically normal articulation as the mass and shape of the ossicles was preserved. Moreover, our patient achieved full ABG closure.

Dislocation of stapes with footplate fracture caused by indirect trauma.

We report the first case of isolated stapedial dislocation caused by indirect head trauma, and present imaging and surgical findings in the case of a 25-year-old woman who suffered hearing loss and dizziness after head trauma caused by a traffic accident. The pure tone average was 60 dB, with an air-bone gap of 50 dB. The stapedial reflex was positive with the probe on the affected ear. Computed tomography scans revealed a longitudinal fracture of the temporal bone and a dislocated stapedial superstructure in the tympanic cavity, adhering to the tympanic membrane. During surgery, it was found that the stapes was broken at the base of the posterior crus and at the anterior one third of the footplate and that the stapedial superstructure was dislocated outward and downward, with the anterior one third of the footplate adhering to the tympanic membrane. The stapedial tendon was connected to the superstructure. Ossicular chain reconstruction was performed with success. In the present case, two mechanisms may have acted together: 1) an increase in perilymphatic pressure that caused the footplate to fracture, and 2) a distorting force that broke the posterior crus, disconnecting the incudostapedial joint, and finally dislocating the stapedial superstructure together with the anterior part of the footplate.

Traumatic stapes fracture with rotation and subluxation into the vestibule and pneumolabyrinth.

A 41-year-old man presented after forceful penetrating ear injury. He had incapacitating vestibular symptoms. Computed tomography revealed pneumolabyrinth with a fractured stapes that was >90 degrees rotated and subluxed into the vestibule, such that the crura and capitulum could be seen in the vestibule. Surgical repair reversed the vestibular symptoms, but there was persistent hearing loss. Stapes fractures are unusual and rarely associated with subluxation into the vestibule. When this does occur, there is usually simple footplate depression. This case demonstrates a rare stapes fracture with pneumolabyrinth and >90 degrees stapes rotation, then subluxation into the vestibule. Laryngoscope, 2009.

Oval window perilymph fistula caused by accidental stapedectomy during ear toilet.

Acquired perilymphatic fistulae can be the result of direct or indirect trauma to the temporal bone, barotraumas, infections or a complication of stapedectomy surgery. We report a case of accidental stapedectomy causing a perilymphatic fistula in an ear with inactive chronic noncholesteatomatous otitis media. This patient had an oval window perilymphatic fistula for 6 weeks prior to surgery without significant permanent sensorineural hearing loss.

Stapediovestibular dislocation with pneumolabyrinth.

Traumatic luxation of the stapes into the vestibule is a rare entity, and the disease complicated with pneumolabyrinth is extremely rare. We report the case of a 72-year-old woman with pneumolabyrinth associated with a stapediovestibular dislocation. The patient presented with vertigo and nystagmus following penetrating trauma to the middle ear. High resolution computed tomography scans demonstrated air in the vestibule and dislocation of the stapes. Exploratory tympanotomy demonstrated oozing of the perilymph from the oval window and depression of the stapes into the vestibule. Pneumolabyrinth and stapes luxation detected by high resolution computed tomography should be predictive of a perilymphatic fistula.

[Impact of TORP diameter on fracture of the footplate]. / Zur Gefahr einer Fraktur der Fussplatte durch unterschiedlich grosse TORP-Prothesenfüsse.

BACKGROUND: A columella-prosthesis is the typical reconstruction procedure of the ossicular chain in cases with a destroyed stapedial arch. Lightweight titanium prostheses are commonly used for this type of surgery. The smaller the prosthesis foot the lower the risk of dislocation and friction of the prosthesis with the bony rim of the oval niche. However, using a smaller prosthesis foot, fracture of the footplate and penetration of the prosthesis into the inner ear are conceivable. METHODS: Using fresh temporal bone preparations, lacking the stapedial arch, in conjunction with a load cell, the force needed to fracture the footplate was measured. Different prostheses with different foot diameters (0.2 - 0.8 mm) were used in these experiments. Furthermore, a human stapes was evaluated morphologically by scanning electron microscopy. RESULTS: The forces leading to fracture of the footplate were measured to be between 250 mN and 980 mN. Statistical analysis showed no significant difference between 0.2 mm and 0.8 mm prosthesis foots. Moreover, different forces were attributed to varying thickness of the stapes footplate. In scanning electron microscopy the rough and uneven bony surface of the footplate could be demonstrated. CONCLUSION: Due to the uneven footplate, only punctual contact of the prosthesis foot can be achieved. Hence, the risk of footplate fracture is not considerably higher by using smaller diameters. However, the use of smaller feet in upcoming generations of TORPs seems to be appropriate.

Unusual middle-ear mischief: trans-tympanic trauma from a hair grip resulting in ossicular, facial nerve and oval window disruption.

A case of piercing of the tympanic membrane, resulting in unusual consequences, is described. This is the first reported case of the long process of a dislocated incus resulting in trauma to the horizontal portion of a dehiscent facial nerve. Simultaneous depression of the stapes footplate resulted in a perilymph leak, but with delayed presentation.

Pneumolabyrinth following traumatic luxation of the stapes into the vestibule.

Pneumolabyrinth can result from traumatic luxation of stapes into the vestibule. The diagnosis of stapes luxation following a head injury can be delayed especially if the otoscopic examination is within normal limits. Here a 15-year-old girl presenting with vertigo and nystagmus following a blunt head injury was presented, whose computerized tomography revealed air in the vestibule and cochlea (pneumolabyrinth) and stapes was found to be luxated into the vestibule.

[Traumatic luxation of the stapes: radiology and surgical outcome]. / Luxation traumatique de l'étrier dans le vestibule: aspect radiologique et conduite à tenir.

OBJECTIVES: To describe the value of high resolution computed tomography scan (HRCT scan) in post traumatic hearing loss. METHOD: HRCT scan of the temporal bone in millimetric cut with axial and coronal views was performed. RESULTS: CT scan confirmed pneumolabyrinth with intact stapes depressed deeply into the vestibule. Surgical exploration was performed and the stapes was gently removed from the vestibule. CONCLUSION: CT scan confirmed the diagnosis and studied the stapes integrity. Hearing deteriorated postoperatively is increased in case of stapes fracture. When a luxation of the stapes into the vestibule is suspected, it is important to determine how deeply and whether it is fractured. When such a case is encountered, high resolution CT scan of the temporal bone must be performed to confirm the diagnosis and to confirm integrity of the stapes.

Traumatic fracture of the stapes and perilymph fistula: report of a case.

We herein report a case of traumatic fracture of the stapes accompanying vestibular window rupture with perilymph fistula, and its diagnosis and surgical procedure were discussed. In the present case, a direct force through the external auditory canal damaged not only the ossicular chain but also the vestibular window. On the exploratory tympanotomy, the complete dislocation and fracture of the stapes with a relatively huge rupture was confirmed. Perilymph fistula was repaired with a connective tissue graft, which was inserted between disrupted vestibular window and the long process of the incus. Vestibular dysfunctions disappeared within 3 days, and a satisfactory audiologic result was obtained one month after surgery.