Impact of superior semicircular canal dehiscence on cochlear implant audiologic outcomes.

PURPOSE: Determine whether adult cochlear implant users with radiographic superior semicircular canal dehiscence experience clinically significant differences in audiological outcomes when compared to cochlear implant users with normal temporal bone anatomy. MATERIALS AND METHODS: Retrospective, single institution review. Adult, post-lingual deaf patients implanted between 2010 and 2020. Inclusion criteria included age 18 years or older, available preoperative computed tomography imaging, and preoperative and postoperative AzBio audiological data for at least 6 months of cochlear implant use. Preoperative and postoperative AzBio Sentence Test scores were compared between patients with normal temporal bone anatomy and those with radiographic superior semicircular canal dehiscence or near dehiscence. RESULTS: 110 patients met inclusion criteria. Mean AzBio score for normal temporal bone anatomy group improved from 35.2 % (SD 28.2) preoperatively to 70.3 % (SD 25.7) postoperatively, an improvement of 35.1 % (SD 28.6). Mean AzBio score for near dehiscent temporal bone anatomy group improved from 26.6 % (SD 28.9) preoperatively to 64.5 % (SD 30.6) postoperatively, an improvement of 37.9 % (SD 27.9). Mean AzBio score for dehiscent temporal bone anatomy group improved from 26.3 % (SD 20.4) preoperatively to 65.1 % (SD 27.6) postoperatively, an improvement of 38.7 % (SD 26.9). Utilizing the one-way analysis of variance test, there was no significant difference in audiologic outcomes between the three groups. CONCLUSIONS: Patients with complete or near complete radiographic superior canal dehiscence at the time of cochlear implantation achieve similar improvements in speech perception scores compared to normal anatomy adult cochlear implant users.

Reliability of clinical diagnosis of masses of the cerebellopontine angle: A retrospective multi-institutional study.

OBJECTIVES: To assess the accuracy of pre-operative diagnosis of masses of the cerebellopontine angle (CPA) when compared to surgical pathology. DESIGN: Retrospective chart review. PARTICIPANTS: Patients who underwent surgery for CPA masses at two tertiary care institutions from 2007 to 2017. MAIN OUTCOME MEASURES: Percent concordance between pre-operative and surgical pathologic diagnosis; sensitivity, specificity, positive predictive value, and negative predictive value for predicted diagnoses. RESULTS: Concordance between pre-operative diagnosis and surgical pathology was 93.2% in 411 sampled patients. Concordance was 57.9% for masses other than vestibular schwannoma. Prediction of vestibular schwannoma and meningioma had high positive (0.95 and 0.97, respectively) and negative (0.76 and 0.99, respectively) predictive values. Prediction of facial neuroma had sensitivity of 0.13 and positive predictive value of 0.25. Headache (p = 0.001) and facial weakness (p = 0.003) were significantly associated with different pathologic profiles. Hearing loss was associated with differences in diagnostic prediction (p = 0.02) but not with differences in surgical pathology (p > 0.05). CONCLUSIONS: Comparison between pre-operative predicted diagnosis and surgical pathology for cerebellopontine angle masses is presented. Vestibular schwannoma and meningioma were effectively identified while rarer CPA masses including facial neuroma were rarely identified correctly. Clinicians caring for patients with CPA masses should be mindful of diagnostic uncertainty which may lead to changes in treatment plan or prognosis.

Analysis of non-posterior canal benign paroxysmal positional vertigo in patients treated using the particle repositioning chair: A large, single-institution series.

PURPOSE: Benign paroxysmal positional vertigo (BPPV) involving the horizontal and superior semicircular canals is difficult to study due to variability in diagnosis. We aim to compare disease, treatment, and outcome characteristics between patients with BPPV of non-posterior semicircular canals (NP-BPPV) and BPPV involving the posterior canal only (P-BPPV) using the particle repositioning chair as a diagnostic and therapeutic tool. METHODS: Retrospective review of patients diagnosed with and treated for BPPV at a high volume otology institution using the particle repositioning chair. RESULTS: A total of 610 patients with BPPV were identified, 19.0% of whom had NP-BPPV. Patients with NP-BPPV were more likely to have bilateral BPPV (52.6% vs. 27.6%, p < 0.0005) and Meniere's disease (12.1% vs. 5.9%, p = 0.02) and were more likely to have caloric weakness (40.3% vs. 24.3%, p = 0.01). Patients with NP-BPPV required more treatments for BPPV (average 3.4 vs. 2.4, p = 0.01) but did not have a significantly different rate of resolution, rate of recurrence, or time to resolution or recurrence than patients with posterior canal BPPV. CONCLUSIONS: Comparison of NP-BPPV and P-BPPV is presented with reliable diagnosis by the particle repositioning chair. NP-BPPV affects 19% of patients with BPPV, and these patients are more likely to have bilateral BPPV and to require more treatment visits but have similar outcomes to those with P-BPPV. NP-BPPV is common and should be part of the differential diagnosis for patients presenting with positional vertigo.

Cardiovascular Risk Factors and Sudden Sensorineural Hearing Loss: A Case-Control Study.

OBJECTIVE: To investigate the role of cardiovascular risk factors (specifically hypertension [HTN], hyperlipidemia/dyslipidemia, diabetes mellitus I and II, and body mass index (BMI) on the development of sudden sensorineural hearing loss (SSNHL). STUDY DESIGN: Case-control retrospective chart review. SETTING: A tertiary referral center. PATIENTS: Patients aged 18 to 85 years who presented to the clinic over a 1-year span (September 17, 2020 to September 17, 2021) for evaluation of sudden sensorineural hearing loss. MAIN OUTCOME MEASURE: Comparing the prevalence of the different cardiovascular risk factors (CVRFs) in patients with sudden sensorineural hearing loss compared with when compared with non-SSNHL patients at a neurotology clinic. RESULTS: Two hundred twenty-three patients with SSNHL were compared with age- and gender-matched comparison group to investigate the prevalence of cardiovascular risk factors within each group. There are no statistically significant differences (p > 0.05) in the prevalence of HTN, hyperlipidemia/dyslipidemia, diabetes mellitus I and II, and BMI in patients with sudden sensorineural hearing loss when compared with non-SSNHL patients at a neurotology clinic. CONCLUSIONS: Despite correlation between CVRF and SSNHL found in some other studies, we did not find a significant correlation between CVRF (diabetes, HTN, dyslipidemia, and high BMI) and SSNHL in our retrospective case control study of patients presenting to a nonacademic tertiary neurotology clinic. Although there may be other factors contributing to the pathogenesis of SSNHL, we have not yet identified these factors.

Rate of Development of Venous Thromboembolism in Lateral Skull Base Surgery.

OBJECTIVES: Venous thromboembolism (VTE) is a major cause of morbidity and mortality for surgical patients. This article aims to determine factors that may have contributed to the development of VTE in patients undergoing lateral skull base surgery, to assess the validity of the Caprini Risk Assessment Model (RAM) score in this subset of patients, and to determine the efficacy of mechanical DVT prophylaxis alone in preventing VTE. STUDY DESIGN: Retrospective chart review. METHODS: A retrospective chart review was conducted of patients who underwent skull base surgery for vestibular schwannoma, and the rate of VTE was assessed. Patient demographics, comorbidities, and treatment factors were examined to determine risk factors associated with the development of a postoperative thrombotic event. Caprini RAM scores were compared for patients who developed a VTE. RESULTS: Among 197 patients, the rate of VTE formation was 3.5%. No individual risk factor independently contributed to the development of a thrombotic event. The mean Caprini RAM score was 4.06 in patients who did not develop a VTE and 5.14 in the patients that did develop a VTE (P = .005). The Caprini score was significant for the risk of VTE formation, with an odds ratio of 2.8 (P = .009, 95% CI = 1.3-6.2). CONCLUSION: Venous thromboembolism rates are relatively low following lateral skull base surgery. While there is no individual risk factor associated with increased VTE risk, the Caprini RAM score appears to be a useful predictor of risk. The Caprini score may be useful in identifying high-risk patients who may benefit from chemoprophylaxis for VTE prevention. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:662-667, 2022.

Audiologic Outcomes After Oval and Round Window Reinforcement Surgery.

INTRODUCTION: Oval window (OW) and round window (RW) reinforcement surgery has been used for symptomatic treatment of multiple clinical entities, most commonly perilymphatic fistula and superior semicircular canal dehiscence. Owing to the theoretical acoustically negative effect of stiffening the windows, there has been concern of an unfavorable effect on audiologic outcomes due to the procedure. The purpose of this study is to specifically evaluate audiologic outcomes after OW and RW reinforcement. METHODS: A retrospective review of patients undergoing transcanal OW or RW reinforcement was completed. Patients were evaluated both as a total group and as two groups separated into "third window" and "two-window" groups based on their specific diagnosis. Primary outcomes included changes in individual pure-tone thresholds, pure-tone average (PTA), air-bone gap, speech reception threshold (SRT), and word recognition scores (WRS) between the preoperative and postoperative groups. RESULTS: Seventy-one patients were included in the study. The combined cohort demonstrated a significant postoperative 2.75 dB increase in the air conduction hearing level at 4000 Hz (p < 0.05). This was almost entirely accounted for by a 2.18 dB increase in the air-bone gap at this frequency (p < 0.05). There were no significant changes in PTA, SRT, or WRS between in the combined group or in the subgroup analysis. CONCLUSION: OW and RW tissue reinforcement resulted in a statistically significant but likely clinically insignificant decrease in hearing at the 4000 Hz frequency. There was no worsening of PTA, WRS, or SRT.

Risk Factors for Complications Following Lateral Skull Base Surgery and the Utility of ICU Monitoring.

OBJECTIVE: To examine the role of intensive care unit (ICU) management following lateral skull base surgery for vestibular schwannoma and identify risk factors for complications warranting admission to the ICU. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: Two hundred consecutive patients undergoing lateral skull base surgery for vestibular schwannomas. INTERVENTION: Lateral skull base approach for resection of vestibular schwannoma and postoperative monitoring. MAIN OUTCOME MEASURES: Patients were grouped if they sustained an ICU complication, a non-ICU complication, or no complication. Analysis was performed to determine patient or treatment factors that may be associated with ICU complications. Multivariate and three-way analysis of variance compared groups, and multivariate logistic regression determined adjusted odds ratios (aOR) for analyzed factors. RESULTS: Seventeen of 200 patients sustained ICU complications (8.5%), most commonly hypertensive urgency (n = 15). Forty-six (23%) sustained non-ICU complications, and 137 (68.5%) had no complications. When controlling for age, sex, obesity, and other comorbidities, only hypertension (aOR 5.43, 95% confidence interval (CI) 1.35-21.73, p = 0.017) and tumor volume (aOR 3.29, 95% CI 1.09-9.96, p = 0.035) were independently associated with increased risk of ICU complications. CONCLUSIONS: The necessity of intensive care following lateral skull base surgery is rare, with the primary ICU complication being hypertensive urgency. Preoperative hypertension and large tumor volume (>4500 mm3) were independently associated with increased risk for ICU complications. These findings may allow for risk stratification of patients appropriate for admission to stepdown units following resection of vestibular schwannomas. Further prospective, multi-center, randomized studies are necessary to validate these findings before systematic changes to current postoperative care practices.

Traumatic versus Idiopathic Benign Positional Vertigo: Analysis of Disease, Treatment, and Outcome Characteristics.

OBJECTIVE: To compare characteristics between traumatic and idiopathic benign paroxysmal positional vertigo (BPPV) focusing on outcomes. STUDY DESIGN: Retrospective chart review. SETTING: High-volume tertiary otology center. SUBJECTS AND METHODS: Records of patients with BPPV treated at a single institution from 2007 to 2017 were analyzed. Traumatic BPPV was defined as BPPV symptoms beginning within 30 days following head trauma. Patient, disease, treatment, and outcome characteristics were compared between traumatic and idiopathic BPPV groups. RESULTS: A total of 1378 patients with BPPV were identified, 110 (8%) of which had traumatic BPPV. The overall resolution rate was 76%, and the recurrence rate was 38%. Patients with traumatic BPPV were younger (mean age: 61 vs 65 years, P = .007) and more likely to be male (40% vs 27%, P = .004) than patients with idiopathic BPPV. Traumatic BPPV was more likely to affect both ears (32% vs 19%, P = .009). No significant association was detected between trauma history and resolution rate, recurrence rate, number of treatment visits, or affected semicircular canals. CONCLUSION: Patients with traumatic BPPV are more likely to be young and male than those with idiopathic disease. Although traumatic BPPV is often bilateral, outcomes for traumatic BPPV may be similar to those for idiopathic BPPV, contrary to prior reports.

Causes of Persistent Positional Vertigo Following Posterior Semicircular Canal Occlusion for Benign Paroxysmal Positional Vertigo.

OBJECTIVE: To report causes of persistent recalcitrant positional vertigo (PRPV) after posterior semicircular canal occlusion (PSCO) for benign paroxysmal positional vertigo (BPPV). STUDY DESIGN: Retrospective chart review. SETTING: Single high-volume otology practice. PATIENTS: Patients diagnosed with BPPV from 2007 to 2017. INTERVENTION: PSCO and follow-up care including diagnostic and particle repositioning maneuvers for recurrent BPPV. MAIN OUTCOME MEASURES: PRPV, defined as recalcitrant positional vertigo for any reason following PSCO. RESULTS: Twenty seven PSCO operations were performed in 26 patients. Twenty five patients (96.2%) had resolution of the Dix-Hallpike test in the operated ear. Eleven patients (42.3%) developed BPPV postoperatively, three (11.5%) in the operated ear and eight (30.8%) in the contralateral ear. Five of eight patients (62.5%) who developed contralateral BPPV had unilateral BPPV preoperatively. Eight patients (30.8%) developed BPPV at least twice after surgery or did not resolve, qualifying as PRPV, and all but one of these events occurred in the nonsurgical ear. No instances of cerebrospinal fluid leak, postoperative infection, facial palsy, clinically significant hearing loss, or death occurred. CONCLUSIONS: PSCO is a safe and effective option for recalcitrant BPPV. However, 30.8% of patients, including patients with initially unilateral BPPV, had recalcitrant positional vertigo postoperatively, usually due to contralateral BPPV. Patients considering PSCO should be counseled regarding this risk to ensure realistic expectations.

Recurrence in Benign Paroxysmal Positional Vertigo: A Large, Single-Institution Study.

OBJECTIVE: To report rates of recurrence in benign paroxysmal positional vertigo (BPPV) and associated patient and disease factors. STUDY DESIGN: Retrospective chart review. SETTING: Single high-volume otology practice. PATIENTS: Patients diagnosed with BPPV from 2007 to 2016 with documented resolution of symptoms. INTERVENTION: Diagnostic and particle repositioning maneuvers for BPPV. MAIN OUTCOME MEASURES: BPPV recurrence, time to recurrence, and ear(s) affected at recurrence. RESULTS: A total of 1,105 patients meeting criteria were identified. Of this population, 37% had recurrence of BPPV in either ear or both ears. Overall same-ear recurrence rate was 28%; 76% of recurrences involved the same ear(s) as initial presentation. Recurrences that occurred after longer disease-free intervals were more likely to involve the opposite ear than early recurrences (p = 0.02). Female sex (40.4% versus 32.7%, p = 0.01) and history of previous BPPV (57.5% versus 32.4%, p < 0.0005) were associated with increased risk of recurrence, while history of Menière's disease, diabetes mellitus, and traumatic etiology were not. Approximately, half (56%) of recurrences occurred within 1 year of resolution. CONCLUSIONS: A large single-institution study of recurrence in BPPV is presented along with Kaplan-Meier disease-free survival curves. Female sex and history of previous BPPV were associated with increased recurrence, while previously suspected risk factors for recurrence including history of Menière's disease, diabetes, and trauma were not. Remote recurrence is more likely to involve the contralateral ear than early recurrence. These data solidify the expected course of treated BPPV allowing for improved clinical care and patient counseling.

Patient, disease, and outcome characteristics of benign paroxysmal positional vertigo with and without Meniere's disease.

BACKGROUND: Meniere's disease (MD)-associated benign paroxysmal positional vertigo (BPPV) is complex and difficult to diagnose, and reports of its prevalence, pathologic features and outcomes are sparse and conflicting. OBJECTIVE: Report disease characteristics and outcomes associated with the presence of MD in patients with BPPV. MATERIALS/METHODS: A retrospective study of patients with BPPV between 2007 and 2017 at a single, high-volume institution. RESULTS: Of 1581 patients with BPPV identified, 7.1% had MD and 71.9% of those patients had BPPV in the same ear(s) as MD. Patients with MD were more likely to have lateral semicircular canalithiasis (11.6% vs. 5.5%, p = .009) and multiple canalithiasis (7.1% vs. 2.5%, p = .005). MD was associated with an increased rate of resolution of BPPV (p = .008) but also increased time to resolution (p = .007). There was no association between MD and recurrence of BPPV. CONCLUSIONS: MD is associated with lateral canalithiasis. Contrary to prior reports, BPPV in MD can affect either ear and was not associated with poorer outcomes than idiopathic BPPV. SIGNIFICANCE: The largest series to date investigating disease and outcome characteristics for BPPV in MD is presented. These data inform diagnosis and expectations in the management of these complex patients.

Treatment of Patients With Benign Paroxysmal Positional Vertigo and Severe Immobility Using the Particle Repositioning Chair: A Retrospective Cohort Study.

OBJECTIVE: To report treatment of benign paroxysmal positional vertigo (BPPV) in patients unable to undergo traditional canalith repositioning maneuvers (CRMs) using a particle repositioning chair (PRC). METHODS: A retrospective chart review was conducted at a single high-volume otology practice of patients diagnosed with BPPV from 2007 to 2017 with immobility prohibiting use of traditional CRMs. Patients were diagnosed and treated using a PRC, and outcome measures including resolution, recurrence, and number of treatment visits were recorded. RESULTS: A total of 34 patients meeting criteria were identified, 24 of whom had cervical spine disease and 10 of whom had other prohibitive immobility. Symptoms were present for between 5 days and 11 years at presentation, with mean and median of 552 and 90 days, respectively. Symptoms resolved in 68% of patients and recurred in 13% of those patients. Most patients required 1 treatment visit. CONCLUSIONS: Successful treatment of patients with BPPV and concomitant immobility prohibiting traditional CRMs is reported using the PRC. Benign paroxysmal positional vertigo in the setting of immobility is an indication for treatment with a PRC if available.

Quality-of-life assessment of Ménière's disease patients after surgical labyrinthectomy.

OBJECTIVE: To examine the impact of surgical labyrinthectomy on quality of life of Ménière's disease patients. STUDY DESIGN: Cross-sectional survey. SETTING: Otology subspecialty referral center. PATIENTS: All patients with Ménière's disease who underwent surgical labyrinthectomy between 1998 and 2004 were selected. Fifty-three patients satisfied inclusion criteria. Completed questionnaires were obtained from 44 patients. INTERVENTION(S): The Ménière's Disease Outcomes Questionnaire is a disease-specific quality-of-life questionnaire. It was used to assess the quality of life of patients before and after surgical labyrinthectomy. The questionnaire encompasses physical, mental, and social well-being domains of quality of life. MAIN OUTCOME MEASURE(S): Change in total quality-of-life score was used to assess the overall impact of surgical labyrinthectomy on subjective patient outcome. Individual quality-of-life domains were also assessed. RESULTS: Forty-three of 44 respondents (98%) had improvement in total score after surgery. The one patient who demonstrated deterioration developed latent contralateral disease. Average preoperative and postoperative scores were 34 +/- 14 and 67 +/- 15, respectively (p < 0.001). All questions showed significant improvement with surgery (p < 0.001) except questions pertaining to memory (no change) and hearing loss (nonsignificant decrease in score). CONCLUSION: This study comprises the first patient-directed assessment of quality-of-life outcomes in Ménière's disease patients after labyrinthectomy. Despite the disadvantage of hearing loss, patients consistently reported significant improvement in all quality-of-life domains and do not report a significant loss of quality of life in terms of their hearing loss. Surgical labyrinthectomy remains a highly effective treatment for Ménière's disease patients.

Success of posterior semicircular canal occlusion and application of the dizziness handicap inventory.

OBJECTIVES: To determine the long-term efficacy and patient satisfaction of posterior semicircular canal occlusion (PSCO) as a treatment for intractable benign paroxysmal positional vertigo (BPPV). STUDY DESIGN AND SETTING: Retrospective analysis of patients with BPPV who underwent PSCO was conducted in a tertiary referral center. Demographic data, clinical records, and audiometric data were reviewed. Dix-Hallpike maneuver, dizziness handicap inventory (DHI), and a specific PSCO questionnaire (PCOQ) were used to measure outcome. RESULTS: Twenty-eight patients underwent PSCO. The mean follow-up time was 40 months. All patients had normalization of the Hallpike test. DHI scores of 20 patients were recorded. The mean preoperative score was 70 compared with postoperative mean of 13 (P < 0.001). Mild hearing loss was found in 1 patient. CONCLUSIONS AND SIGNIFICANCE: PSCO is highly successful. The DHI scores postoperatively show significant improvement. The PCOQ revealed an overall 85% patient satisfaction rate. PSCO is a safe and effective intervention for intractable BPPV with a high patient satisfaction rate. EBM RATING: C-4.

Acoustic Reflex Screening of Conductive Hearing Loss for Third Window Disorders.

OBJECTIVE: This study examines the effectiveness of acoustic reflexes in screening for third window disorders (eg, superior semicircular canal dehiscence) prior to middle ear exploration for conductive hearing loss. STUDY DESIGN: Case series with chart review. SETTING: Outpatient tertiary otology center. SUBJECTS AND METHODS: A review was performed of 212 ears with acoustic reflexes, performed as part of the evaluation of conductive hearing loss in patients without evidence of chronic otitis media. The etiology of hearing loss was determined from intraoperative findings and computed tomography imaging. The relationship between acoustic reflexes and conductive hearing loss etiology was assessed. RESULTS: Eighty-eight percent of ears (166 of 189) demonstrating absence of all acoustic reflexes had an ossicular etiology of conductive hearing loss. Fifty-two percent of ears (12 of 23) with at least 1 detectable acoustic reflex had a nonossicular etiology. The positive and negative predictive values for an ossicular etiology were 89% and 57% when acoustic reflexes were used alone for screening, 89% and 39% when third window symptoms were used alone, and 94% and 71% when reflexes and symptoms were used together, respectively. CONCLUSION: Acoustic reflex testing is an effective means of screening for third window disorders in patients with a conductive hearing loss. Questioning for third window symptoms should complement screening. The detection of even 1 acoustic reflex or third window symptom (regardless of reflex status) should prompt further workup prior to middle ear exploration.

Intralabyrinthine schwannomas mimic cochleovestibular disease: symptoms from tumor mass effect in the labyrinth.

OBJECTIVE: To describe symptoms from intralabyrinthine schwannomas specific from more common vestibular schwannomas of the internal auditory canal or cerebellopontine angle resulting from mass effect from the tumor within the labyrinth. PATIENTS: Eight patients diagnosed as having intralabyrinthine schwannomas from 2000 to 2014 were examined retrospectively from two tertiary neurotologic centers. INTERVENTIONS: Diagnosis of intralabyrinthine schwannoma was made with gadolinium-enhanced magnetic resonance imaging scans. Heavily T2-weighted sequences were used to verify mass within the fluid-filled labyrinth. Patients then underwent audiometric and vestibular testing when appropriate. Treatment consisted of observation or surgical resection. MAIN OUTCOME MEASURES: Clinical symptoms, magnetic resonance imaging scans, audiometric and videonystagmography data, and operative findings were reviewed. RESULTS: Five of the eight patients had positional vertigo or nystagmus on testing. One patient's only complaint was positional vertigo without auditory symptoms. Three of the patients demonstrated mixed hearing loss. Two patients underwent resection of their tumors, one because of tumor growth and the other because of intractable vertigo. CONCLUSION: These data show that a high proportion within our series displayed symptoms of positional vertigo and mixed hearing loss, which are symptoms not typical of nonintralabyrinthine schwannomas. One patient's only reported symptom was positional vertigo. These symptoms may arise from the effect of the tumor's mass exerted on the cochlear and vestibular end organs.

Round window gentamicin absorption: an in vivo human model.

OBJECTIVE/HYPOTHESIS: Using a novel human labyrinthine sampling model, in vivo gentamicin absorption through the round window can be measured. STUDY DESIGN: A prospective study. METHODS: Gentamicin was delivered either transtympanically (preoperative) or through a facial recess approach (intraoperative). The lateral semicircular canal and vestibule were opened, and by means of a microsyringe, labyrinthine fluid was aspirated. A sample of serum was also drawn. In all patients cerebrospinal fluid was also drawn. The samples were analyzed using a standard chemistry analyzer. RESULTS: Intratympanic gentamicin diffused through the round window membrane and achieved concentrations in the labyrinthine fluid ranging from 0 to 16 mg/L. Intratympanic gentamicin was absorbed into the systemic circulation in 4 of 11 patients with serum levels ranging from 0.3 to 0.4 mg/L. No gentamicin was detected in the cerebrospinal fluid. CONCLUSIONS: Intratympanic gentamicin diffuses rapidly through the round window membrane and achieves significant levels in the inner ear. Thus, this new model can be used to assess round window permeability to clinically relevant medications such as steroids and ototopical antibiotics.

Benign paroxysmal positional vertigo.

PURPOSE OF REVIEW: To review benign paroxysmal positional vertigo (BPPV) and some of the recent literature. As BPPV is such a common diagnosis, it is important to understand the disorder and treatment considerations. RECENT FINDINGS: Although BPPV is typically an easy diagnosis to make, one must be aware of the differential diagnosis. An unusual entity, convergence spasm, is recently presented and discussed as an addition to the differential diagnosis. The recent literature confirms the efficacy of treatment of BPPV. Large studies of horizontal canal BPPV support the success of the barbeque roll and present the simple head shake as a possible treatment in the apogeotropic form. There is reported success with the less often discussed Gufoni (and its variations) maneuver. The presence of orthoptic nystagmus during treatment has positive predictive value for the success of the maneuver. Although uncommon, canal conversion is important to recognize during treatment as it can be readily treated. SUMMARY: BPPV is a very common cause of dizziness and generally straightforward to identify and treat. Awareness of possible horizontal canal variants and nonvestibular differential diagnosis possibilities is important. Repositioning maneuvers of various types are typically successful and understanding the nuances is important in assuring successful outcomes.