The relationship between post-traumatic ossicular injuries and conductive hearing loss: A 3D-CT study

Endoscopic ossiculoplasty in traumatic conductive hearing loss with intact tympanic membrane: a five-year experience

BACKGROUND

Exploratory tympanotomy in cases of traumatic ossicular disruption with intact tympanic membrane is crucial for both diagnostic and therapeutic purposes. Performing this procedure using the endoscope is gaining popularity. Hence, this study aimed to demonstrate varieties of ossicular pathology and their management in our institution.

METHODS

A retrospective evaluation was conducted of 136 ears in patients with traumatic ossicular disruption with an intact tympanic membrane, who underwent endoscopic exploratory tympanotomy. A proposed algorithm was followed, to incorporate different traumatic ossicular possibilities. Assessment of hearing outcomes and surgical complications was performed six months post-operatively.

RESULTS

Incudostapedial dislocation was the most commonly encountered type of traumatic ossicular disruption (35.3 per cent). Air conduction threshold improved significantly following endoscopic ossiculoplasty, from 50.9 ± 6.35 dB pre-operatively to 22.35 ± 3.27 dB post-operatively, with successful air-bone gap closure.

CONCLUSION

Endoscopic ear surgery is effective in the diagnosis and management of challenging cases of post-traumatic ossicular disruption with an intact tympanic membrane.

CT of Skull Base Fractures: Classification Systems, Complications, and Management

As advances in prehospital and early hospital care improve survival of the head-injured patient, radiologists are increasingly charged with understanding the myriad skull base fracture management implications conferred by CT. Successfully parlaying knowledge of skull base anatomy and fracture patterns into precise actionable clinical recommendations is a challenging task. The authors aim to provide a pragmatic overview of CT for skull base fractures within the broader context of diagnostic and treatment planning algorithms. Laterobasal, frontobasal, and posterior basal fracture patterns are emphasized. CT often plays a complementary, supportive, or confirmatory role in management of skull base fractures in conjunction with results of physical examination, laboratory testing, and neurosensory evaluation. CT provides prognostic information about short- and long-term risk of cerebrospinal fluid (CSF) leak, encephalocele, meningitis, facial nerve paralysis, hearing and vision loss, cholesteatoma, vascular injuries, and various cranial nerve palsies and syndromes. The radiologist should leverage understanding of specific strengths and limitations of CT to anticipate next steps in the skull base fracture management plan. Additional imaging is warranted to clarify ambiguity (particularly for potential sources of CSF leak); in other cases, clinical and CT criteria alone are sufficient to determine the need for intervention and the choice of surgical approach. The radiologist should be able to envision stepping into a multidisciplinary planning discussion and engaging neurotologists, neuro-ophthalmologists, neurosurgeons, neurointerventionalists, and facial reconstructive surgeons to help synthesize an optimal management plan after reviewing the skull base CT findings at hand. Online supplemental material is available for this article. ^©RSNA, 2021.

Outcomes of ossicular disruption in traumatic facial paralysis: a case series

BACKGROUND

As tympanotomy using the transcanal approach was a routine surgical technique for traumatic ossicular disruption, the efficacy of the posterior tympanum approach was rarely explored.

AIM

This study aimed to investigate whether the hearing outcomes improved after simultaneous ossiculoplasty and facial nerve decompression using the posterior tympanum approach compared with the transcanal approach.

MATERIAL AND METHODS

The data of 11 patients who underwent ossiculoplasty and facial nerve decompression using the posterior tympanum approach and 21 patients who underwent ossiculoplasty via transcannal approach were analyzed.

RESULTS

The average air-bone gap (ABG) of patients undergoing posterior tympanotomy showed a statistically significant improvement. Postoperative ABG within 20 dB was observed in 81.8% of patients in the posterior tympanum group and 76.2% of patients in the transcanal group. However, the ABG closure in the two groups was not statistically different.

CONCLUSIONS AND SIGNIFICANCE

Simultaneous ossiculoplasty using the posterior tympanum approach was practical, and the hearing outcomes were promising for the patients with traumatic facial nerve paralysis and ossicular disruption.

Traumatic dislocation of middle ear ossicles: A new computed tomography classification predicting hearing outcome

Objectives

To assess the feasibility of radiologic measurements and find out whether hearing outcome could be predicted based on computer tomography (CT) scan evaluation in patients with temporal bone fractures and suspected ossicular joint dislocation.

Methods

We assessed 4002 temporal bone CT scans and identified 34 patients with reported ossicular joint dislocation due to trauma. We excluded those with no proven traumatic ossicular dislocation in CT scan and patients with bilateral temporal bone fractures. We measured four parameters such as malleus-incus axis distance, malleus-incus angle at midpoints, malleus- incus axis angle and ossicular joint space. The contralateral healthy side served as its own control. Hearing outcome 1–3 months after the index visit was analyzed. We assessed diagnostic accuracy and performed a logistic regression using radiologic measurement parameters for outcome prediction of conductive hearing loss (defined as >20dB air-bone gap).

Results

We found excellent inter-rater agreement on the measurement of axis deviation between incus and malleus in CT scans (interclass correlation coefficient 0.81). The larger the deviation of incus and malleus axis, the higher probability of poor hearing outcome (odds ratio (OR) 2.67 per 0.1mm, p = .006). A cut-off value for the axis deviation of 0.25mm showed a sensitivity of 0.778 and a specificity of 0.94 (p < .001) for discrimination between poor and good hearing outcome in terms of conductive hearing loss.

Conclusion

Adequate assessment of high resolution CT scans of temporal bone in which ossicular chain dislocation had occurred after trauma was feasible. Axis deviations of the incus and the malleus were strongly predictive for poor hearing outcome in terms of air conduction 1–3 months after trauma. We propose a 3-level classification system for hearing outcome prediction based on radiologic measures.

Long-term cochlear implantation outcomes in patients following head injury

OBJECTIVE

In cases of a severe to profound sensorineural hearing loss following head injury, the cochlear implant (CI) is the primary option for auditory rehabilitation. Few studies, however, have investigated long-term CI outcomes in patients following head trauma, including those without temporal bone fracture (TBF). Herein, the aim of this study is to examine CI outcomes following cases of head injury with and without TBF.

METHODS

Audiometric outcomes of patients who received a CI due to a head injury resulting in severe to profound hearing loss at two tertiary care hospitals were analyzed. Patients were divided into those who received a CI in a fractured temporal bone (group A, n = 11 patients corresponding to 15 ears) and those who received a CI in a non-fractured temporal bone (group B, n = 8 patients corresponding to nine ears). Primary outcomes included duration of deafness prior to CI and postoperative consonant-nucleus-constant whole word (CNC) scores.

RESULTS

Nineteen patients (84% male), corresponding to 24 CIs, were identified. Fifteen CI were performed on ears with TBF (group A), and nine CI were performed on ears without TBF (group B). No patients had an enlarged vestibular aqueduct (EVA). The mean duration of deafness was 5.7 and 11.3 years in group A and group B, respectively. The mean duration of CI follow-up (CI experience) was 6.5 years in group A and 2.1 years in group B. The overall mean postoperative CNC score for all subjects was 68.6% (±21.2%, n = 19 with CNC testing). There was no difference in CNC score between group A and group B (69.8% and 66% respectively, P = .639).

CONCLUSION

The study is among the largest series examining long-term outcomes of CI after head injury. CI is an effective method for auditory rehabilitation in patients after head injury.

LEVEL OF EVIDENCE

IV.

Labyrinthine concussion: Historic otopathologic antecedents of a challenging diagnosis

OBJECTIVE

The term "labyrinthine concussion" has evolved to mean audiovestibular dysfunction in the absence of a temporal bone fracture (TBF). Despite a multitude of case descriptions of labyrinthine concussion, the precise pathophysiology remains poorly understood. Herein, we explore the historical otopathologic underpinnings of the diagnosis of labyrinthine concussion with a focus on the auditory pathway during the late 19th to the mid-20th centuries and conclude with a discussion of its contemporary relevance.

METHODS AND DATA SOURCES

A review of primary and secondary medical sources written in English, German, and French on otopathology labyrinthine concussion studies from the late-19th to the mid-20th centuries.

RESULTS

Around the turn of the 20th century, otopathologists identified histologic changes in the temporal bones of individuals that sustained head injury without TBFs. Based on these otopathologic findings in humans, early experiments investigating the pathophysiology of labyrinthine concussion were performed in animals through either the delivery of blows to the head or direct introduction of a pressure wave into the labyrinthine fluid. Collectively, otopathologists hypothesized that predominant mechanisms for labyrinthine concussion included inner ear hemorrhage, cochleovestibular nerve traction injury, direct damage from a labyrinthine fluid pressure wave, or vasomotor dysfunction.

CONCLUSION

Historical study shows a variety of inner ear pathologies potentially responsible for auditory dysfunction following head injury. Understanding the history and otopathology of labyrinthine concussion may help clinicians focus on new pathways toward novel research and improved patient care.

Transcanal endoscopic ear surgery for traumatic ossicular injury

Background: Transcanal endoscopic ear surgery (TEES) for traumatic ossicular injuries (TOI) is not well studied.Objectives: To analyze the treatment outcomes of TEES for TOI.Material and methods: Retrospective case review of fifteen patients (15 ears) with TOI was performed. The patients underwent an either ossiculoplasty or stapes surgery according to status of the ossicular chain using ear endoscopes. Postoperative audiometric results and complications were analyzed.Results: All subjects demonstrated improvement in their air conduction threshold and air-bone gap (ABG). The mean preoperative air conduction threshold and ABG were 55.3 dB (SD: 12.8) and 33.0 dB (SD: 9.5), respectively. Postoperatively, the air conduction threshold and ABG significantly improved to 28.1 dB (SD: 16.0) and 8.1 dB (SD: 4.5), respectively. Separation of the incudomalleolar joint accompanied by defect of the tegmen, which was not discernible on preoperative imaging, could be identified without additional incision or mastoidectomy. No patients experienced complications or a sensorineural hearing loss. Conversion to open approach was not necessary for any of the 15 procedures performed.Conclusion and significance: TEES for TOI yielded favorable audiometric results without any complication. TEES can provide an alternative method to manage TOI with the advantage of avoidance of skin incisions and mastoidectomy.

Traumatic Injury of the Petrous Part of the Temporal Bone: Keys for Reporting a Complex Diagnosis

Fractures of the petrous part of the temporal bone are a common lesion of the base of the skull; most of these fractures result from high-energy trauma. In patients with multiple trauma, these injuries can be detected on CT scans of the head and neck, where the direct and indirect signs are usually sufficient to establish the diagnosis. It is important to these fractures because the temporal bone has critical structures and the complexity of this region increases the risk of error unless special care is taken. This article reviews the key anatomical points, the systematization of the imaging findings, and the classifications used for temporal bone fracture. We emphasize the usefulness of identifying and describing the findings in relation to important structures in this region, of looking for unseen fractures suspected through indirect signs, and of identifying anatomical structures that can simulate fractures. We point out that the classical classifications of these fractures are less useful, although they continue to be used for treatment decisions.

Otopathologic Changes in the Cochlea following Head Injury without Temporal Bone Fracture

Objective

Hearing loss following temporal bone (TB) fracture may result from direct transection of the middle and inner ear. The pathophysiology of hearing loss due to head injury without TB fracture, however, is not well understood. Few reports describe otopathologic findings. Herein, we investigate the pathologic findings of patients who sustained a head injury without evidence of a TB fracture.

Study Design

Otopathology study.

Setting

Otopathology laboratory.

Subjects

Subjects with a history of head injury without TB fracture.

Methods

The TBs of patients with head injury were evaluated by light microscopy. Inner ear anatomy was evaluated, including counts of spiral ganglion cells (SGCs), hair cells, pillar cells, atrophy of the stria vascularis, and the presence of endolymphatic hydrops. SGC counts were compared with those of historical age-matched controls.

Results

All cases (N = 6 TBs) had evidence of inner ear pathology. Of the 6 cases, 2 (33%) had severe loss of hair cells in all 3 turns of the cochlea, and 4 (67%) cases demonstrated moderate to severe loss at the basal turn of the cochlea. Four cases had scattered atrophy of the stria vascularis, and 3 (50%) had cochlear hydrops. The number of total SGCs was decreased, with an average 53% loss (range, 25%-79%) as compared with controls. The SGC count loss was evenly distributed along Rosenthal’s canal.

Conclusions

Patients with a history of head injury without TB fracture demonstrate inner ear pathology. Further studies are necessary to determine if otopathology findings are directly attributable to trauma.