Towards a consensus on a hearing preservation classification system.

CONCLUSION: The comprehensive Hearing Preservation classification system presented in this paper is suitable for use for all cochlear implant users with measurable pre-operative residual hearing. If adopted as a universal reporting standard, as it was designed to be, it should prove highly beneficial by enabling future studies to quickly and easily compare the results of previous studies and meta-analyze their data. OBJECTIVES: To develop a comprehensive Hearing Preservation classification system suitable for use for all cochlear implant users with measurable pre-operative residual hearing. METHODS: The HEARRING group discussed and reviewed a number of different propositions of a HP classification systems and reviewed critical appraisals to develop a qualitative system in accordance with the prerequisites. RESULTS: The Hearing Preservation Classification System proposed herein fulfills the following necessary criteria: 1) classification is independent from users' initial hearing, 2) it is appropriate for all cochlear implant users with measurable pre-operative residual hearing, 3) it covers the whole range of pure tone average from 0 to 120 dB; 4) it is easy to use and easy to understand.

Human experience with canal plugging.

Canal occlusion/plugging is a very effective technique with a low risk to hearing. The series of posterior semicircular canal occlusions described in this review now becomes the largest in the literature to date. It continues to support this procedure as the treatment of choice for intractable benign paroxysmal positional vertigo (BPPV). All 44 operated ears were relieved of BPPV, with one patient having an atypical late recurrence. Of the 40 ears with normal preoperative hearing, one had a delayed (3-month) sudden and permanent profound loss, while one other had a mild (20 dB) loss. Six patients had protracted courses of imbalance and motion sensitivity. Canal plugging has led to several new and innovative developments including the partial labyrinthectomy for difficult-to-access skull base lesions and superior semicircular canal plugging for dehiscence. These new procedures and their development are reviewed in this paper.

Comparison of open, percutaneous, and translaryngeal tracheostomies.

INTRODUCTION: With 3 tracheostomy techniques currently available, controversy exists regarding which is safest and most economical. Percutaneous (PDT) and the new translaryngeal (TLT) tracheostomies are cited as more cost-effective than the traditional open surgical procedure because they are bedside techniques. Our objective was to compare the perioperative and postoperative complications of the 3 techniques. STUDY DESIGN: This was a prospective trial involving 100 consecutive patients who underwent tracheostomy between April and December of 1997 at the London Health Sciences Centre and St Joseph's Health Centre in London, Canada. RESULTS: Fifty open tracheostomies were performed. Indications included prolonged ventilation (n = 42), airway protection (n = 5), pulmonary hygiene (n = 2), and sleep apnea (n = 1). A tension pneumothorax was the one significant intraoperative complication. Fifteen postoperative complications occurred, most notable of which was a 2-L hemorrhage at 24 hours. Thirty-seven TLTs were performed, 20 in patients with coagulopathy. Indications were prolonged intubation (n = 27), airway protection (n = 9), and pulmonary hygiene (n = 1). One intraoperative complication of accidental decannulation occurred. One postoperative complication, a pretracheal abscess, occurred in a decannulated transplant patient 2 weeks after the procedure. Thirteen PDTs were performed. Indications were prolonged intubation (n = 6), airway protection (n = 6), and tracheal toilet (n = 1). No significant complications occurred. CONCLUSIONS: TLT and PDT have fewer complications than the traditional open technique. TLT appears to have the greatest utility in the coagulopathic patient.

Approach to the vestibular patient and driving: A patient perspective.

OBJECTIVES: To learn about the impact of dizziness on driving from a patient perspective and to present an approach to the vestibular patient and driving. DESIGN: An anonymous questionnaire completed by 265 dizzy patients at 3 different centers. RESULTS: The participants were experienced drivers who needed to drive to function normally (83%). Those with constant or severe dizziness comprised a higher risk group of drivers. Although few had ever been warned not to drive, 52% said that if they were warned to stop driving, they would not. Most thought that it was the doctor's role to report unsafe drivers to the authorities (P < 0.001, chi2 = 87.2670). CONCLUSIONS: The diagnosis of a vestibular disorder should not alone be grounds to suspend a patient's driver's license. Legislation should be amended to better reflect the views of doctors and patients alike.

Corticosteroid pharmacokinetics in the inner ear fluids: an animal study followed by clinical application.

OBJECTIVE: Autoimmune disease (e.g., Cogan syndrome) and other inflammatory inner ear diseases may ravage the labyrinth if not treated aggressively with antiinflammatory medication. Corticosteroids are the mainstay of treatment, yet, partly because of the existence of the blood-labyrinthine barrier, the ideal drug, dose, and route of administration are currently unknown. STUDY DESIGN: In the present study, we established cochlear fluid pharmacokinetic profiles of hydrocortisone, methylprednisolone, and dexamethasone in the guinea pig following oral, intravenous, and topical (intratympanic) administration. High-performance liquid chromatography was used to determine the drug concentrations, and comparisons were made with simultaneous pharmacokinetic profiles from blood and cerebrospinal fluid. RESULTS: Our findings demonstrated a much higher penetration of all three drugs into the cochlear fluids following topical application as compared with systemic administration, with methylprednisolone showing the best profile. DISCUSSION: The results suggested that intratympanic administration of corticosteroids might be more efficacious while avoiding high blood levels and therefore the deleterious side effects of systemic use. CLINICAL APPLICATION: Thirty-seven patients with various inner ear disorders causing sensorineural hearing loss were subsequently treated using intratympanic corticosteroids, 20 with dexamethasone, and 17 with methlyprednisolone. Patients with immune-mediated hearing losses showed the best results, with notable improvement also seen in several cases of a "sudden deafness." No benefit was seen in patients with cochlear hydrops or those with sudden deterioration of a preexisting hearing loss. Three patients developed a transient otitis media related to the treatments, easily controlled with antibiotics. There were no cases of treatment-induced hearing loss and no permanent tympanic membrane perforations. CONCLUSIONS: Overall injection of intratympanic corticosteroids for the treatment of hearing loss in inner ear disorders appears to be both safe and highly effective for certain disorders. The concept of this technique is supported by animal experimental data. The findings from the present study warrant further clinical application and experimental investigation.

Intratympanic gentamicin titration therapy for intractable Meniere's disease.

OBJECTIVE: This study aimed to assess the efficacy and morbidity of intratympanic gentamicin titration therapy on patients with intractable unilateral Meniere's disease. STUDY DESIGN: The study design was a retrospective chart review and patient interviews. SETTING: The study was conducted at a tertiary referral ambulatory dizziness clinic at the London Health Sciences Centre, University Campus, from July 1992 to June 1997. INTERVENTION: Eighty-three patients received weekly intratympanic gentamicin injections in their diseased ear. Treatments were terminated after four injections or sooner if patients met clinical or audiologic criteria. Sixty-eight patients were available for detailed follow-up. MAIN OUTCOME MEASURES: Vertigo frequency, hearing status, personal disability ratings, tinnitus level, and caloric responses before and after gentamicin therapy were measured. RESULTS: Eighty-four percent of patients showed complete, and an additional 6% showed substantial, vertigo control. At 24 months, 17% of patients demonstrated a clinically significant (10-dB) reduction in hearing, but 26% showed a significant hearing improvement. Overall, the group showed no combined statistically significant changes in any of the hearing parameters. No patients had an "extreme" drop in hearing (>30 dB). CONCLUSIONS: Intratympanic gentamicin titration therapy provides excellent vertigo control with a low incidence of hearing loss.

Case of the month: June 1997--a 42 year old man with left facial weakness.

A 42 yr old male presented with left facial weakness. MRI showed lesions affecting the distal seventh nerve and third division of the trigeminal nerve. The seventh nerve was biopsied and showed a malignant epithelioid schwannoma. The patient underwent extensive resection followed by irradiation. This is one of very few examples of intracranial malignant peripheral nerve sheath tumors and the first reported example of an intracranial malignant epithelioid schwannoma. The literature is reviewed and completeness of resection appears to be the most pertinent prognostic factor.

Molecular analysis of the POU3F4 gene in patients with clinical and radiographic evidence of X-linked mixed deafness with perilymphatic gusher.

The molecular defect in some patients with X-linked mixed deafness with perilymphatic gusher at stapes surgery (DFN3) was recently attributed to mutations in the POU3F4 gene. In this manuscript we describe the molecular analysis of the POU3F4 gene in 5 patients with clinical and radiographic evidence of DFN3. Novel mutations were found in 2 of the 5 patients analyzed, while 3 had an entirely normal protein coding sequence. The fact that 3 of the 5 patients with clinical histories and radiographic abnormalities characteristic of X-linked mixed deafness with perilymphatic gusher displayed normal POU3F4 gene sequences supports the possibility that not all patients with the characteristic phenotype have involvement of the POU3F4 gene.

Reporting of vestibular patients who are unfit to drive: survey of Canadian otolaryngologists.

OBJECTIVES: The objectives of this study were (1) to learn about the concerns and current practices of Canadian otolaryngologists with regard to the reporting of vestibular patients; and (2) to examine the three different reporting mandates in Canada by surveying otolaryngologists in Ontario, Alberta, and British Columbia, and to assess the level of satisfaction with reporting methods. METHOD: A survey was mailed to all members of the Canadian Society of Otolaryngology-Head and Neck Surgery in Ontario, Alberta, and British Columbia, using a modified version of the "Dillman Total Survey Design Method." RESULTS: The survey had an overall response rate of 62.8%. Although many respondents have considered reporting vestibular patients (82.2%) and have warned patients not to drive without reporting them (84.2%), only 25.3% actually have. The great majority (91.8%) felt that unfit drivers should be brought to the attention of the transportation authority. There was no consensus of opinion on the best method of reporting, but only 23.3% of those surveyed supported mandatory physician reporting. Ontario otolaryngologists were significantly less satisfied with the fitness-to-drive legislation in their province than were those from Alberta or British Columbia (chi 2 = 22.7, p = .001). Almost three times as many Ontario respondents have actually reported a vestibular patient (chi 2 = 6.7, p = .01). CONCLUSIONS: The study results suggest that mandatory physician reporting is not a satisfactory method of reporting unfit-to-drive vestibular patients. It is highly recommended that all physicians become familiar with the reporting guidelines in their province or territory and comply with their legal obligations.

Particulate matter in the posterior semicircular canal.

The pathoetiology of benign paroxysmal positional vertigo (BPPV) is controversial. Particulate matter within the posterior semicircular canal has been identified intraoperatively in patients with BPPV but has also been reported in non-BPPV patients at the time of translabyrinthine surgery (Parnes LS, McClure JA. Free-floating endolymphatic particles: a new operative finding during posterior semicircular canal occlusion. Laryngoscope 1992;102:988-92; Schuknecht HF, Ruby RRF. Cupulolithiasis. Adv Otorhinolaryngol 1973;20: 434-43; Kveton JF, Kashgarian M. Particulate matter within the membranous labyrinth: pathologic or normal? Am J Otol 1994;15:173-6). The nature of the particulate matter remains unknown. The purpose of this study was to prospectively examine the posterior semicircular canal of patients with and without a clinical history of BPPV for the presence of particulate matter. Seventy-three patients without BPPV symptoms undergoing labyrinthine surgery (vestibular schwannoma excision or labyrinthectomy) and 26 patients with BPPV undergoing the posterior semicircular canal occlusion procedure were compared. Additionally, 70 archived temporal bones without a history of BPPV were examined microscopically for the presence of particulate matter within the lumen of the membranous labyrinth. No particles were observed intraoperatively in any of the 73 patients without a history of BPPV. Particulate matter was observed in 8 of 26 patients at the time of the posterior semicircular canal occlusion procedure for intractable BPPV. Of the 70 temporal bones examined, 31 did not show significant postmortem changes and also did not demonstrate cupulolithiasis or canalithiasis. Particulate matter from within the membranous posterior semicircular canal was removed from one patient at the time of posterior semicircular canal occlusion for intractable BPPV symptoms and was examined by scanning electron microscopy. The particulate matter appeared morphologically consistent with degenerating otoconia. These data show a statistically significant association between the presence of particles within the posterior semicircular canal in this study and the symptom complex of BPPV.

Impact of vestibular disorders on fitness to drive: a census of the American Neurotology Society.

BACKGROUND: Legislation for reporting unfit-to-drive patients by physicians varies dramatically among U.S. states and Canadian provinces. The impact of vestibular disease on driving safety is not well described in the literature. OBJECTIVES: (1) to learn more about the critical issues and current practices of neurotologists regarding reporting of vestibular patients and (2) to make recommendations for reporting patients with vestibular disorders. STUDY DESIGN: A mailed census of members of the American Neurotology Society using a questionnaire based on a modified Dillman Total Design Survey Method. RESULTS: Most respondents are aware of the potential safety risks of patients who drive with vestibular diseases, most notably those with Tumarkins' attacks. Although many have counselled patients (94%) and considered reporting vestibular patients (75%), few actually have (14%). There was no consensus of opinion on a method of reporting unfit-to-drive patients. Only 18.9% of respondents supported mandatory physician reporting. Respondents who live in states where reporting is not mandatory and who are aware of this fact are (a) more satisfied with their state's legislation (chi 2 = 60.1, p = 0.001) and (b) less likely to report patients who they consider unfit-to-drive (chi 2 = 10.6, p = 0.03). CONCLUSIONS: In that there is no general consensus amongst respondents and the relative safety risks seem low in comparison to other disorders, at present we do not advocate mandatory reporting of patients with vestibular disorders.

Identification of a hot spot for microdeletions in patients with X-linked deafness type 3 (DFN3) 900 kb proximal to the DFN3 gene POU3F4.

Small mutations in the POU domain gene POU3F4 were recently shown to cause X-linked deafness type 3 (DFN3) in nine unrelated males. The POU3F4 gene was found to be located outside four of five deletions associated with DFN3. Two of these deletions were situated more than 400 kb proximal to POU3F4. Employing PCR analysis of sequence tagged sites from this region we initially identified novel deletions in two DFN3 patients. To investigate this chromosomal segment in more detail, we extended a previously established 850 kb cosmid contig in the centromeric direction to a total size of 1500 kb. Cosmids from this contig were hybridized to DNA of 11 unrelated males with DFN3. In two patients, we identified deletions encompassing the POU3F4 gene and variably sized segments of Xq21.1. In six of the nine remaining patients which lacked mutations in the POU3F4 gene, smaller deletions were identified which, with one exception, overlap in a 8 kb segment 900 kb proximal to the POU3F4 gene. In one patient, we identified several small deletions in the vicinity of the 8 kb DNA segment. Together, deletions account for 56% (13/23) of all known DFN3 mutations, most (10/13) of which do not encompass the POU3F4 gene. The combined molecular data suggest that the deletion hot spot region in Xq21.1 contains another DFN3 gene or, alternatively, a sequence element involved in transcriptional regulation of POU3F4.

Update on posterior canal occlusion for benign paroxysmal positional vertigo.

Most, if not all, cases of BPPV appear to result from free-floating posterior semicircular canal endolymph particles. Particle repositioning alleviates symptoms and findings in the vast majority of patients. For the small intractable group of nonresponders, posterior semicircular canal occlusion remains a safe and highly efficacious procedure. This new technique has also paved the way for even newer and most invasive inner ear procedures.

Comparative perilymph permeability of cephalosporins and its significance in the treatment and prevention of suppurative labyrinthitis.

Cephalosporins are nonototoxic antibiotics that provide excellent coverage for almost all bacteria that can cause suppurative labyrinthitis. In this study we performed comparative perilymph permeability determinations of the three cephalosporins that we deemed to have the most clinical potential in these varied situations. Perilymph pharmacokinetic profiles were established for ceftazidime, cefuroxime, and cefotaxime and its metabolite desacetylcefotaxime in 36 guinea pigs by using the technique of high-performance liquid chromatography. At 1, 2, 3, 4, and 6 hours after intravenous administration of the three cephalosporins at a dose of 100 mg/kg of body weight, ceftazidime consistently exhibited the highest perilymph concentration. Desacetylcefotaxime showed the next highest capacity for penetration into perilymph. Keeping in mind that the choice of drug for the treatment of suppurative labyrinthitis should be based foremost on culture and sensitivity studies, we consider ceftazidime to be the first-line agent for treatment and prevention of both meningogenic labyrinthitis and labyrinthitis complicating acute or chronic otitis media.

Intratympanic gentamicin therapy for Menière's disease: preliminary comparison of two regimens.

Selective chemical ablation of the vestibular endorgan using intratympanic gentamicin is an effective and safe treatment for incapacitating vertigo in patients with unilateral Menière's disease. A major risk of the treatment is sensorineural hearing loss. In this retrospective study, two different regimens of intratympanic gentamicin therapy are compared. In one group, multiple daily doses were administered in hospital over 4 consecutive days. The other group received single treatments at weekly intervals on an outpatient basis, following pretreatment audiometric and clinical assessment. We adopted the weekly protocol to theoretically reduce the incidence of treatment-related hearing loss by a more controlled titration of dosing. Preliminary results indicate that the weekly interval treatment offers equivalent efficacy with considerably less risk to hearing.

Pharmacokinetic profiles of ceftazidime in cochlear perilymph, cerebrospinal fluid and plasma: a high-performance liquid chromatographic study.

A pharmacokinetic profile of the antibiotic ceftazidime was established for perilymph, cerbrospinal fluid (CSF) and plasma in 12 guinea pigs using the technique of high-performance liquid chromatography. The mean peak levels of 13.35 mg/l in perilymph and 140.54 mg/l in plasma were reached within the first hour after a single intravenous dose of 100 mg/kg. The CSF mean peak level of 5.36 mg/l, however, was not attained until 3 h after injection. The half-life was about 4 h in perilymph, more than 6 h in CSF and less than 2 h in plasma. Six hours following administration, the perilymph drug concentration remained higher than the plasma level. The study indicates that ceftazidime has excellent penetration into perilymph. It is concluded that ceftazidime should be a very useful agent in the treatment of bacterial labyrinthitis caused by susceptible organisms.