Brendan P. O’Connell

Electrode Location and Audiologic Performance After Cochlear Implantation: A Comparative Study Between Nucleus CI422 and CI512 Electrode Arrays.

Objectives: 1) Compare rates of scala tympani (ST) insertion between Nucleus CI422 Slim Straight electrodes and Nucleus CI512 Contour Advance electrodes; 2) examine audiometric performance with both electrode arrays, while controlling for electrode location. Setting: Tertiary academic hospital. Patients: Fifty-six post-lingually deafened adults undergoing cochlear implant (CI). Main Outcome Measures: Primary outcome measures of interest were scalar electrode location and postoperative audiologic performance. Results: Fifty-six implants in 49 patients were included; 20 were implanted with Nucleus CI422 Slim Straight electrodes, and 36 were implanted with Nucleus CI512 Contour Advance electrodes. Overall, 62.5% (35 of 56) of implants had all electrodes located within the ST. Significantly, higher rates of ST insertion (90%) were observed for Nucleus CI422 Slim Straight electrodes when compared with Nucleus CI512 Contour Advance electrodes (47.2%) (p = 0.002). In regards to audiologic performance, consonant-nucleus-consonant (CNC) scores were significantly higher for Nucleus CI422 Slim Straight electrodes (55.4%) compared with Nucleus CI512 Contour Advance electrodes (36.5%) (p = 0.005). In addition, AzBio scores were better for Nucleus CI422 Slim Straight electrodes (71.2%) when compared with Nucleus CI512 Contour Advance electrodes (46.7%) (p = 0.004). Controlling for ST insertion, higher AzBio scores were again observed for Nucleus CI422 Slim Straight electrodes (p = 0.02). Conclusions: The results of this study demonstrate that the Nucleus CI422 Slim Straight electrode is more likely to reside entirely within the ST when compared with the Nucleus CI512 Contour Advance electrode. Furthermore, AzBio scores were superior for patients with Nucleus CI422 Slim Straight electrodes in all patients, as well as those with only ST insertions.

Ossiculoplasty With Titanium Prostheses in Patients With Intact Stapes: Comparison of TORP Versus PORP.

Objectives: Inferior rotation of the stapes or a small middle ear cleft can make placement of partial ossicular replacement prostheses (PORP) challenging. This study examines outcomes of total titanium prosthesis (TORP) ossiculoplasty in such patients and compares the results to PORPs. Study Design: Review of prospective database. Setting: Tertiary hospital. Patients: Patients with an intact/mobile stapes undergoing titanium ossicular chain reconstruction from 2002 to 2014. Intervention: Ossicular chain reconstruction. Outcomes: Hearing outcomes included ABG, closure of ABG(&Dgr;ABG), SRT, improvement in SRT(&Dgr;SRT), achievement of ABG ⩽20 dB, and stability over time. Results: Eighty-three patients were included; 56 were PORPs and 27 were TORPs. At initial follow-up (<6 mo), mean ABG and &Dgr;ABG in the TORP group were 20.6 and 11.7 dB, respectively. Postoperative ABG⩽20 dB was achieved in 60.0% of TORPs. At longer-term follow-up (mean 54.0 mo), hearing remained stable in TORPs. Specifically, the mean ABG and &Dgr;ABG were 17.7 and 13.3 dB, respectively. Sixty-three percent of TORPs achieved ABG ⩽20 dB at later follow-up. When compared PORPs at both short and longer-term follow-ups, no differences in hearing outcomes were noted. A small, but statistically significant, deterioration in both ABG and SRT was observed within the PORP group (p = 0.02 and <0.01, respectively). Conclusion: TORP reconstruction in patients with an intact stapes is associated with good short and longer-term hearing results. Furthermore, hearing outcomes within TORPs remain stable at follow-up >12 months postoperatively. Results did not differ when compared with traditional PORP reconstruction, suggesting that TORP through an intact stapes arch is an acceptable alternative to PORP reconstruction in patients with challenging anatomy.

Preliminary Study on the Stability of Beta-2 Transferrin in Extracorporeal Cerebrospinal Fluid

Objective. Detection of beta-2 transferrin in rhinorrhea fluid is a sensitive and specific method for the diagnosis of a cerebrospinal fluid (CSF) leak. Patients may be asked to collect this fluid at home to obtain an adequate volume for detection, and thus the age and storage conditions of these specimens may be variable upon analysis. The purpose of this study is to understand how age, storage temperature, and exposure to mucus affect the ability to detect beta-2 transferrin in CSF. Study Design. Case series with planned data collection. Setting. Tertiary care university hospital. Subjects and Methods. This study consists of 6 patients undergoing endoscopic CSF leak repair. CSF was collected directly from a lumbar drain (n = 4) or from nasal drainage (n = 2). Specimens were stored at 4°C (n = 3) or room temperature (n = 3). Samples were tested for the presence of beta-2 transferrin for up to 7 days using standard immunofixation electrophoresis techniques. Results. Beta-2 transferrin was detected in all specimens through day 7 regardless of storage temperature or collection site (95% exact binomial confidence interval of 0%-46%). Conclusions. Beta-2 transferrin remains detectable in extracorporeal CSF for up to 7 days regardless of storage at room temperature or exposure to nasal mucus. Negative detection in patient specimens up to a week old is therefore not likely to be caused by protein degradation.

Cervical and Ocular VEMP Testing in Diagnosing Superior Semicircular Canal Dehiscence

Objective To determine the sensitivity and specificity of ocular and cervical vestibular evoked myogenic potentials (VEMPs) in the diagnosis of superior semicircular canal dehiscence (SCD) and to describe the VEMP response characteristics that are most sensitive to SCD and compare the findings to previous reports. Study Design Case series with chart review. Setting Two tertiary neurotologic referral centers. Subjects and Methods Cervical and ocular VEMP peak-to-peak amplitudes and thresholds from 39 adult patients older than 18 years with surgically confirmed SCD were compared with 84 age-matched controls. Results Using receiver operating characteristic (ROC) curves, cervical VEMP (cVEMP) amplitudes, cVEMP thresholds, and ocular VEMP (oVEMP) amplitudes had areas under the curve of 0.731, 0.912, and 0.856, respectively, all of which were statistically significant (P < .0001). For cVEMP thresholds, at the clinical equivalent ≤85-dB normalized hearing level (nHL) threshold, the sensitivity and specificity were 97.3% and 31.3%, respectively. At the ≤70-dB nHL threshold, the sensitivity and specificity were 73.0% and 94.0%, respectively. For oVEMP amplitudes >12.0 µV, the sensitivity and specificity were 78.6% and 81.7%, respectively. Conclusion Data from this multicenter study suggest that both cVEMP thresholds and oVEMP amplitudes remain good diagnostic tests for identifying SCD, with each test dependent on a number of factors. The sensitivity and specificity of these individual tests may vary slightly between centers depending on testing parameters used.

The Natural History of Petroclival Meningiomas: A Volumetric Study

OBJECTIVES This study characterizes primary petroclival meningioma growth rates, before intervention, using volumetric analysis. In addition, predictors of growth are analyzed. METHODS Patients with previously untreated petroclival meningiomas were retrospectively reviewed (1999-2015). Image analysis software was used to perform volumetric analyses of tumor size and growth. Three-dimensional segmentation volumetric analyses were compared with volumes estimated utilizing three orthogonal dimensions. Tumor growth was defined as a 15% increase in volume. RESULTS Thirty-four patients who underwent at least two magnetic resonance imaging (MRI) studies before intervention were included. The mean age was 55.2 years, and 65.7% were women. The mean tumor volume at presentation was 5.6 cm (range, 0.1-25.8 cm) as determined from segmentation volumetric analysis. At a mean follow-up of 44.5 months (range, 3.7-125.1 mo), 88.2% of tumors grew. The mean annual volumetric growth rate was 2.38 cm/yr (-0.63 to 25.9 cm/yr). Tumor volume, T2 hyperintensity within the tumor, peritumoral edema, and ataxia and/or cerebellar symptoms at presentation were all significantly associated with greater rates of tumor growth. Ultimately, 10 (29.4%) patients underwent treatment during the follow-up period. CONCLUSION Our experience demonstrates that the vast majority (88%) of untreated petroclival meningiomas grow; the mean volumetric growth rate was noted to be 2.38 cm/yr. We found a significant association between increased growth rate and larger tumor size at diagnosis, T2 hyperintensity within the tumor, peritumoral edema, and the presence of ataxia and/or cerebellar symptoms.

An Easy and Reliable Method to Locate the Dehiscence During Middle Fossa Superior Canal Dehiscence Surgery: It is a (C)inch.

Objective: The middle fossa floor lacks reliable surface landmarks. In cases of superior semicircular canal dehiscence (SSCD), multiple skull base defects may be present, further confounding the location of the labyrinth. Misidentification of the SSCD during surgery may lead to treatment failure or sensorineural hearing loss. Anecdotally, the authors have observed the distance from the lateral edge of the craniotomy to the SSCD to be consistently 1 inch. Herein, we present radiologic evidence of this practical and clinically useful relationship. Patients: All patients at two tertiary care academic referral centers with high-resolution temporal bone computed tomography (CT) evidence of SSCD were retrospectively reviewed. Intervention(s): Review of high-resolution temporal bone CT. Main Outcome Measures: The horizontal distance from the outer cortex of the squama temporalis immediately superior to the bony external auditory canal (approximating lateral edge of craniotomy) to the SSCD was measured in the coronal plane by two independent reviewers. Results: A total of 151 adult ears with SSCD were analyzed. A Shapiro-Wilk goodness-of-fit test confirmed that measurements were normally distributed. Pearson inter-rater correlation was 0.95, confirming very strong agreement. The mean distance between the outer cortex of the squama temporalis and SSCD was 25.9 mm, or 1.02 inches. Sixty-eight percent of the SSCD population would fall between 0.92 and 1.12 inches and 95% would lie between 0.83 and 1.21 inches. Conclusions: The horizontal distance from the outer cortex of the squama temporalis to the SSCD consistently approximates 1 inch. This easily remembered distance can aid surgeons in locating or confirming the SSCD during middle fossa surgery.

Real-Time Intracochlear Electrocochleography Obtained Directly Through a Cochlear Implant

HYPOTHESIS Utilizing the cochlear implant to record electrophysiologic responses during device placement is a feasible and efficacious technique for monitoring near real-time cochlear physiology during and following electrode insertion. BACKGROUND Minimizing intracochlear trauma during cochlear implantation has emerged as a highly researched area to help improve patient performance. Currently, conventional cochlear implant technology allows for the recording of electrically evoked compound action potentials (eCAPs). Acoustically evoked potentials may be more sensitive in detecting physiologic changes occurring as a result of electrode insertion. Electrocochleography obtained from within the cochlea allows hair cell and neural response monitoring along the cochlear spiral at locations where changes most likely would occur. METHODS Intracochlear electrocochleography (ECochG) was recorded from the cochlear implant during surgery in 14 subjects. A long acquisition time (54.5 ms), capable of measuring potentials from the low frequency-serving apical region of the cochlea (125 and 500 Hz) was employed. Two distinct intracochlear processing methods were used and compared in obtaining electrophysiologic data. RESULTS Measureable intracochlear ECochG responses were obtained from all 14 participants. The 1st harmonic distortions (cochlear microphonic and auditory nerve neurophonic) generally increased steadily with electrode insertion. Electrode and frequency scan following insertion revealed that response amplitude varied based on location of recording electrode and frequency of stimulation. Exquisite sensitivity to manipulation during round window muscle packing was demonstrated. CONCLUSION Intracochlear ECochG recorded from the electrode array of the cochlear implant is a highly feasible technique that sheds light on cochlear micromechanics during cochlear implant electrode placement.

Correlation of Superior Canal Dehiscence Surface Area With Vestibular Evoked Myogenic Potentials, Audiometric Thresholds, and Dizziness Handicap.

Objective: To correlate objective measures of vestibular and audiometric function as well as subjective measures of dizziness handicap with the surface area of the superior canal dehiscence (SCD). Study Design: Retrospective chart review and radiological analysis. Setting: Single tertiary academic referral center. Patients: Preoperative computed tomography imaging, patient survey, audiometric thresholds, and vestibular evoked myogenic potential (VEMP) testing in patients with confirmed SCD. Intervention(s): Image analysis techniques were developed to measure the surface area of each SCD in computed tomography imaging. Main Outcome Measure(s): Preoperative ocular and cervical VEMPs, air and bone conduction thresholds, air-bone gap, dizziness handicap inventory scores, and surface area of the SCD. Results: Fifty-three patients (mean age 52.7 yr) with 84 SCD were analyzed. The median surface area of dehiscence was 1.44 mm2 (0.068–8.23 mm2). Ocular VEMP amplitudes (r = 0.61, p <0.0001), cervical VEMP amplitudes (r = 0.62, p <0.0001), air conduction thresholds at 250 Hz (r = 0.25, p = 0.043), and air-bone gap at 500 Hz (r = 0.27, p = 0.01) positively correlated with increasing size of dehiscence. An inverse relationship between cervical VEMP thresholds (r = −0.56, p < 0.0001) and surface area of the dehiscence was observed. No association between dizziness handicap and surface area was identified. Conclusion: Among patients with confirmed SCD, ocular and cervical VEMP amplitudes, cervical VEMP thresholds, and air conduction thresholds at 250 Hz are significantly correlated with the surface area of the dehiscence.

Systematic Review and Meta-analysis of Surgical Complications following Cochlear Implantation in Canal Wall Down Mastoid Cavities:

Objective We sought to assess the complication rates following cochlear implantation in canal wall down mastoid cavities in adults and children. Data Sources A systematic review of English articles from PubMed, Web of Science, EMBASE, and the Cochrane Library. Additional studies were identified by reviewing the reference lists of the originally identified studies. Review Methods Studies were included that reported on surgical outcomes following cochlear implantation in canal wall down mastoid cavities. Two authors, using predefined data fields, independently reviewed all articles while tabulating study quality indicators. A meta-analysis of proportions was conducted on select cohorts to determine weighted complication rates. Results Forty-two articles were included that accounted for 424 patients and described surgical outcomes following cochlear implantation in canal wall down mastoid cavities. In a comparison of the postoperative complication rates, overclosing the external auditory meatus had significantly fewer global complications than did maintaining a canal wall down mastoid cavity (P = .027). In a comparison of the complication rates (1) between staging the cochlear implantation and performing external auditory meatus overclosure simultaneously with cochlear implantation and (2) between pediatric and adult cochlear implantation recipients with external auditory meatus overclosure, there were no significant differences (P = .085 and P = .92, respectively). Conclusion Overclosing the external auditory meatus at the same time of cochlear implantation leads to significantly fewer complications when compared with maintaining a canal wall down mastoid cavity with soft tissue coverage of the electrode array.

Temporal Bone Mucormycosis.

Case Details: We present a case of temporal bone mucormycosis in a 71-year-old female with diabetes mellitus who presented to the emergency department with facial nerve paresis, otorrhea, and contralateral hemiparesis. After undergoing a tympanomastoidectomy, the patient’s pathology exhibited fungal hyphae consistent with mucormycosis. Discussion: To our knowledge, there have been 9 reported cases of temporal bone mucormycosis, 3 of which presented with facial nerve paresis, all with some subsequent improvement. In this case, facial paralysis persisted at the time of last follow-up (2 months) despite surgery and intravenous antifungals. We also review and summarize the temporal bone mucormycosis literature. Conclusion: Temporal bone mucormycosis is a rare and morbid infectious disease, though its outcomes appear to be different for patients who present with isolated temporal bone disease as compared to those individuals who develop temporal bone mucormycosis secondary to a rhinologic source.