Jameson K. Mattingly

Effects of Skin Thickness on Cochlear Input Signal Using Transcutaneous Bone Conduction Implants.

Hypothesis Intracochlear sound pressures (PIC) and velocity measurements of the stapes, round window, and promontory (VStap/RW/Prom) will show frequency-dependent attenuation using magnet-based transcutaneous bone conduction implants (TCBCIs) in comparison with direct-connect skin-penetrating implants (DCBCIs). Background TCBCIs have recently been introduced as alternatives to DCBCIs. Clinical studies have demonstrated elevated high-frequency thresholds for TCBCIs as compared with DCBCIs; however, little data exist examining the direct effect of skin thickness on the cochlear input signal using TCBCIs. Methods Using seven cadaveric heads, PIC was measured in the scala vestibuli and tympani with fiber-optic pressure sensors concurrently with VStap/RW/Prom via laser Doppler vibrometry. Ipsilateral titanium implant fixtures were placed and connected to either a DCBCI or a TCBCI. Soft tissue flaps with varying thicknesses (no flap and 3, 6, and 9 mm) were placed successively between the magnetic plate and sound processor magnet. A bone conduction transducer coupled to custom software provided pure-tone stimuli between 120 and 10,240 Hz. Results Stimulation via the DCBCI produced the largest response magnitudes. The TCBCI showed similar PSV/ST and VStap/RW/Prom with no intervening flap and a frequency-dependent nonlinear reduction of magnitude with increasing flap thickness. Phase shows a comparable dependence on transmission delay as the acoustic baseline, and the slope steepens at higher frequencies as flap thickness increases, suggesting a longer group delay. Conclusion Proper soft tissue management is critical to optimize the cochlear input signal. The skin thickness–related effects on cochlear response magnitudes should be taken into account when selecting patients for a TCBCI.

Cochlear Implant Electrode Effect on Sound Energy Transfer Within the Cochlea During Acoustic Stimulation.

Hypothesis: Cochlear implants (CIs) designed for hearing preservation will not alter mechanical properties of the middle and inner ears as measured by intracochlear pressure (PIC) and stapes velocity (Vstap). Background: CIs designed to provide combined electroacoustic stimulation are now available. To maintain functional acoustic hearing, it is important to know if a CI electrode can alter middle or inner ear mechanics because any alteration could contribute to elevated low-frequency thresholds in electroacoustic stimulation patients. Methods: Seven human cadaveric temporal bones were prepared, and pure-tone stimuli from 120 Hz to 10 kHz were presented at a range of intensities up to 110 dB sound pressure level. PIC in the scala vestibuli (PSV) and tympani (PST) were measured with fiber-optic pressure sensors concurrently with VStap using laser Doppler vibrometry. Five CI electrodes from two different manufacturers with varying dimensions were inserted via a round window approach at six different depths (16–25 mm). Results: The responses of PIC and VStap to acoustic stimulation were assessed as a function of stimulus frequency, normalized to sound pressure level in the external auditory canal, at baseline and electrode-inserted conditions. Responses measured with electrodes inserted were generally within approximately 5 dB of baseline, indicating little effect of CI electrode insertion on PIC and VStap. Overall, mean differences across conditions were small for all responses, and no substantial differences were consistently visible across electrode types. Conclusion: Results suggest that the influence of a CI electrode on middle and inner ear mechanics is minimal despite variation in electrode lengths and configurations.

Treatment of Juvenile Recurrent Parotitis of Childhood: An Analysis of Effectiveness

IMPORTANCE Juvenile recurrent parotitis (JRP) is characterized by recurrent painful swelling of the parotid gland that occurs in the pediatric population. Sialendoscopy with and without ductal corticosteroid infusion (DCI) has been found to be effective in the treatment of JRP and autoimmune parotitis. OBJECTIVE To determine the utility of instrumentation vs pharmacotherapy alone for juvenile recurrent parotitis. DESIGN, SETTING, AND PARTICIPANTS A retrospective medical record review of pediatric patients undergoing DCI without sialendoscopy at a tertiary pediatric hospital was conducted. The medical records were reviewed to determine the frequency of parotitis events before and after treatment. A multiquestion telephone survey of patients and their parents who underwent the procedure was then conducted to determine patient satisfaction. INTERVENTIONS Ductal corticosteroid infusion with hydrocortisone through catheter inserted in the parotid duct. MAIN OUTCOMES AND MEASURES Frequency of symptoms before and after treatment and parental satisfaction with the treatment. RESULTS Twelve patients with a mean age of 6.7 years were identified. The mean duration and frequency of symptoms before the procedure were 22 months and every 2 months, respectively. Five patients had a recurrence, on average 4 months after the procedure. Four patients underwent repeated surgical procedures. All had a longer duration between episodes compared with before DCI. Eight parents participated in the survey on satisfaction with the procedure, and 75% reported improvement in their childs life postprocedure. CONCLUSIONS AND RELEVANCE Current literature shows sialendoscopy with corticosteroid application is successful in treating JRP, but it is unclear whether corticosteroid application alone would treat JRP equally. This study shows that DCI alone has similar results as sialendoscopy with corticosteroid application, indicating that it is the corticosteroid application and not the sialendoscopy causing improvement in symptoms. Because JRP must be differentiated from sialolithiasis, we recommend ultrasonography of the involved parotid(s) prior to using DCI alone to ensure no stone is present. Sialendoscopy should be reserved to rule out other parotid ductal pathologic conditions.

A Preliminary Investigation of the Air-Bone Gap: Changes in Intracochlear Sound Pressure With Air- and Bone-conducted Stimuli After Cochlear Implantation.

Hypothesis: A cochlear implant electrode within the cochlea contributes to the air-bone gap (ABG) component of postoperative changes in residual hearing after electrode insertion. Background: Preservation of residual hearing after cochlear implantation has gained importance as simultaneous electric-acoustic stimulation allows for improved speech outcomes. Postoperative loss of residual hearing has previously been attributed to sensorineural changes; however, presence of increased postoperative ABG remains unexplained and could result in part from altered cochlear mechanics. Here, we sought to investigate changes to these mechanics via intracochlear pressure measurements before and after electrode implantation to quantify the contribution to postoperative ABG. Methods: Human cadaveric heads were implanted with titanium fixtures for bone conduction transducers. Velocities of stapes capitulum and cochlear promontory between the two windows were measured using single-axis laser Doppler vibrometry and fiber-optic sensors measured intracochlear pressures in scala vestibuli and tympani for air- and bone-conducted stimuli before and after cochlear implant electrode insertion through the round window. Results: Intracochlear pressures revealed only slightly reduced responses to air-conducted stimuli consistent with previous literature. No significant changes were noted to bone-conducted stimuli after implantation. Velocities of the stapes capitulum and the cochlear promontory to both stimuli were stable after electrode placement. Conclusion: Presence of a cochlear implant electrode causes alterations in intracochlear sound pressure levels to air, but not bone, conducted stimuli and helps to explain changes in residual hearing noted clinically. These results suggest the possibility of a cochlear conductive component to postoperative changes in hearing sensitivity.

Sudden Bilateral Hearing Loss After Cervical and Ocular Vestibular Evoked Myogenic Potentials.

Objective Cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs) are commonly used in evaluation of neurotologic disorders. We present a case of sudden bilateral hearing loss immediately after oVEMP and cVEMP testing. The hearing loss did not recover. To our knowledge, no previous case reports discuss sudden hearing loss, especially bilateral, associated with VEMP testing. Patient A single patient with sudden bilateral hearing loss that has persisted after cVEMP and oVEMP. Intervention The patient had a history of chronic daily dizziness. She underwent vestibular function testing that included cVEMP and oVEMP testing. A significant bilateral sensorineural hearing loss was noted immediately after cVEMP and oVEMP testing and confirmed with audiometric testing. Despite the use of oral steroids, her hearing loss did not recover. Main Outcome Measures Serial audiograms, calculated maximum total sound energies to each ear. Results Pre-VEMP versus post-VEMP audiograms show increased thresholds and decreased word recognition scores; total sound energy delivered to each ear shows significant sound exposure. Conclusion Although VEMP testing is thought to be safe and well tolerated, a significant amount of sound can be delivered to the cochlea, and certain individuals may be susceptible to acoustic trauma at these levels. We recommend limits for VEMP stimuli levels and attention to total sound exposure when multiple trials are used.

Intracochlear Pressure Transients During Cochlear Implant Electrode Insertion.

Hypothesis: Cochlear implant (CI) electrode insertion into the round window induces pressure transients in the cochlear fluid comparable to high-intensity sound transients. Background: Many patients receiving a CI have some remaining functional hearing at low frequencies; thus, devices and surgical techniques have been developed to use this residual hearing. To maintain functional acoustic hearing, it is important to retain function of any hair cells and auditory nerve fibers innervating the basilar membrane; however, in a subset of patients, residual low-frequency hearing is lost after CI insertion. Here, we test the hypothesis that transient intracochlear pressure spikes are generated during CI electrode insertion, which could cause damage and compromise residual hearing. Methods: Human cadaveric temporal bones were prepared with an extended facial recess. Pressures in the scala vestibuli and tympani were measured with fiber-optic pressure sensors inserted into the cochlea near the oval and round windows, whereas CI electrodes (five styles from two manufacturers) were inserted into the cochlea via a round window approach. Results: Pressures in the scala tympani tended to be larger in magnitude than pressures in the scala vestibuli, consistent with electrode insertion into the scala tympani. CI electrode insertion produced a range of pressure transients in the cochlea that could occur alone or as part of a train of spikes with equivalent peak sound pressure levels in excess of 170 dB sound pressure level. Instances of pressure transients varied with electrode styles. Conclusion: Results suggest electrode design, insertion mechanism, and surgical technique affect the magnitude and rate of intracochlear pressure transients during CI electrode insertion. Pressure transients showed intensities similar to those elicited by high-level sounds and thus could cause damage to the basilar membrane and/or hair cells.

Unilateral endonasal transcribriform approach with septal transposition for olfactory groove meningioma: can olfaction be preserved?

BackgroundLoss of olfaction has been considered inevitable in endoscopic endonasal resection of olfactory groove meningiomas. Olfaction preservation may be feasible through an endonasal unilateral transcribriform approach, with the option for expansion using septal transposition and contralateral preservation of the olfactory apparatus.MethodsAn expanded unilateral endonasal transcribriform approach with septal transposition was performed in five cadaver heads. The approach was applied in a surgical case of a 24 × 26-mm olfactory groove meningioma originating from the right cribriform plate with partially intact olfaction.ResultsThe surgical approach offered adequate exposure to the anterior skull base bilaterally. The nasal/septal mucosa was preserved on the contralateral side. Gross total resection of the meningioma was achieved with the successful preservation of the contralateral olfactory apparatus and preoperative olfaction. Six months later, the left nasal cavity showed no disruption of the mucosal lining and the right side was at the appropriate stage of healing for a harvested nasoseptal flap. One year later, the preoperative olfactory function was intact and favorably viewed by the patient. Objective testing of olfaction showed microsomia.ConclusionsOlfaction preservation may be feasible in the endoscopic endonasal resection of a unilateral olfactory groove meningioma through a unilateral transcribriform approach with septal transposition and preservation of the contralateral olfactory apparatus.

Drill-induced Cochlear Injury During Otologic Surgery: Intracochlear Pressure Evidence of Acoustic Trauma

HYPOTHESIS Drilling on the incus produces intracochlear pressure changes comparable to pressures created by high-intensity acoustic stimuli. BACKGROUND New-onset sensorineural hearing loss (SNHL) following mastoid surgery can occur secondary to inadvertent drilling on the ossicular chain. To investigate this, we test the hypothesis that high sound pressure levels are generated when a high-speed drill contacts the incus. METHODS Human cadaveric heads underwent mastoidectomy, and fiber-optic sensors were placed in scala tympani and vestibuli to measure intracochlear pressures (PIC). Stapes velocities (Vstap) were measured using single-axis laser Doppler vibrometry. PIC and Vstap were measured while drilling on the incus. Four-millimeter diamond and cutting burrs were used at drill speeds of 20k, 50k, and 80k Hz. RESULTS No differences in peak equivalent ear canal noise exposures (134-165 dB SPL) were seen between drill speeds or burr types. Root-mean-square PIC amplitude calculated in third-octave bandwidths around 0.5, 1, 2, 4, and 8 kHz revealed equivalent ear canal (EAC) pressures up to 110 to 112 dB SPL. A statistically significant trend toward increasing noise exposure with decreasing drill speed was seen. No significant differences were noted between burr types. Calculations of equivalent EAC pressure from Vstap were significantly higher at 101 to 116 dB SPL. CONCLUSION Our results suggest that incidental drilling on the ossicular chain can generate PIC comparable to high-intensity acoustic stimulation. Drill speed, but not burr type, significantly affected the magnitude of PIC. Inadvertent drilling on the ossicular chain produces intense cochlear stimulation that could cause SNHL.

Cervical bronchogenic cysts: case report and review of the literature.

Pediatric cervical masses can present a diagnostic dilemma given their broad differential diagnosis. We present a 3-year-old girl with a midline anterior neck mass found to have histopathologic findings consistent with a bronchogenic cyst. Although rare, bronchogenic cysts should be considered in the differential diagnosis in both lateral and anterior pediatric cervical masses as their pathophysiology and embryogenesis differ considerably from more common cervical masses. Imaging is an important aspect in the pre-operative work-up, although diagnosis is only made after histopathologic analysis. Complete surgical excision is the definitive treatment.

Semicircular Canal Pressure Changes During High-intensity Acoustic Stimulation

HYPOTHESIS Acoustic stimulation generates measurable sound pressure levels in the semicircular canals. BACKGROUND High-intensity acoustic stimuli can cause hearing loss and balance disruptions. To examine the propagation of acoustic stimuli to the vestibular end-organs, we simultaneously measured fluid pressure in the cochlea and semicircular canals during both air- and bone-conducted sound presentation. METHODS Five full-cephalic human cadaveric heads were prepared bilaterally with a mastoidectomy and extended facial recess. Vestibular pressures were measured within the superior, lateral, and posterior semicircular canals, and referenced to intracochlear pressure within the scala vestibuli with fiber-optic pressure probes. Pressures were measured concurrently with laser Doppler vibrometry measurements of stapes velocity during stimulation with both air- and bone-conduction. Stimuli were pure tones between 100 Hz and 14 kHz presented with custom closed-field loudspeakers for air-conducted sounds and via commercially available bone-anchored device for bone-conducted sounds. RESULTS Pressures recorded in the superior, lateral, and posterior semicircular canals in response to sound stimulation were equal to or greater in magnitude than those recorded in the scala vestibuli (up to 20 dB higher). The pressure magnitudes varied across canals in a frequency-dependent manner. CONCLUSION High sound pressure levels were recorded in the semicircular canals with sound stimulation, suggesting that similar acoustical energy is transmitted to the semicircular canals and the cochlea. Since these intralabyrinthine pressures exceed intracochlear pressure levels, our results suggest that the vestibular end-organs may also be at risk for injury during exposure to high-intensity acoustic stimuli known to cause trauma in the auditory system.