Bradley W. Kesser

Long-term hearing preservation after middle fossa removal of vestibular schwannoma.

OBJECTIVE: We sought to determine long-term hearing preservation in vestibular schwannoma patients after undergoing middle fossa resection. STUDY DESIGN, SETTING, AND OUTCOME MEASURES: We conducted a retrospective chart review of patients undergoing middle fossa resection from 1990 to 1995 at a tertiary care center. Pure-tone thresholds, before resection and at least 5 years after resection, and speech discrimination scores are reported. RESULTS: Seventy percent of patients with immediate postoperative hearing maintained serviceable hearing at more than 5 years after surgery. Pure-tone average in the operative ear changed at the same rate as hearing in the unoperated ear during this follow-up period. CONCLUSIONS: More than two thirds of patients who underwent middle fossa resection of a vestibular schwannoma with some hearing postoperatively maintain that hearing at greater than 5 years of follow-up. Surgery alone does not have a negative impact on long-term hearing preservation. (Otolaryngol Head Neck Surg 2003;129:660-5.)

The Jahrsdoerfer Grading Scale in Surgery to Repair Congenital Aural Atresia

OBJECTIVE To determine the predictive ability of the Jahrsdoerfer grading scale score in congenital aural atresia surgery. DESIGN Retrospective review of medical records. SETTING Tertiary referral center. PATIENTS One hundred eight patients with aural atresia. MAIN OUTCOME MEASURES Demographic data, preoperative Jahrsdoerfer score, and postoperative audiometric outcomes were reviewed. One month postoperative, 4-tone pure-tone averages and speech reception thresholds were compared between ears scoring 6 or lower, 7, and 8 or higher on the Jahrsdoerfer grading scale. The percentage of ears with a speech reception threshold of 30 dB hearing level or lower for each group was calculated and compared between groups. Individual anatomical structures on the Jahrsdoerfer grading scale were evaluated for their ability to predict postoperative audiometric success. RESULTS Of 116 ears evaluated, postoperative 4-tone pure-tone averages and speech reception thresholds were significantly poorer in ears scoring 6 or less on the Jahrsdoerfer grading scale compared with ears scoring 7 or higher (P < .02, t test). Ears scoring 6 or less had a 45% chance of achieving a postoperative speech reception threshold of 30 dB hearing level or lower, while ears scoring 7 or higher had an 89% chance (P < .01, chi(2) test). Lack of middle ear aeration was the only anatomical factor predictive of poor audiometric outcome. CONCLUSIONS Compared with patients with a Jahrsdoerfer score of 6 or lower, patients with a score of 7 or higher had significantly better hearing postoperatively. Middle ear aeration may be the most important predictor of postoperative hearing outcome. The Jahrsdoerfer grading scale is an invaluable tool in the preoperative evaluation of patients with congenital aural atresia.

Time course of hearing loss in an animal model of pneumococcal meningitis.

A leading cause of morbidity from bacterial meningitis is an irreversible, usually profound sensorineural hearing loss, with an incidence as high as 30% in some studies. Bacterial meningitis remains the most common cause of acquired postnatal sensorineural deafness. Although several clinical studies have examined the long-term outcome of hearing in meningitis, few studies have examined the time course of hearing loss during the acute course of the disease. We have developed an animal model of meningogenic hearing loss in the rat and have plotted the time course of that hearing loss. Serial auditory brain stem responses (ABRs) were measured in rats inoculated in the cisterna magna (subarachnoid space) with Streptococcus pneumoniae (10 5 to 10 7 colony-forming units). All rats injected developed meningitis as evidenced by increased cerebrospinal fluid (CSF) white cell counts and positive CSF cultures. Serial ABR measurements taken 6, 12, 15, 18, 21, and 24 hours after inoculation demonstrated significant threshold shifts and eventual loss of the ABR waveform as compared with measurements in control rats injected with sterile culture medium. Hearing loss began approximately 12 to 15 hours after inoculation and progressed to complete loss by 24 hours (17 of 18 animals). No correlation was found between the magnitude of hearing loss and CSF white cell count or bacterial titer. Temporal bone histology of rats with meningitis shows a dense inflammatory cell infiltrate throughout the subarachnoid space. Labyrinthine inflammatory cells were confined to the scala tympani.

Gene Therapy and Stem Cell Transplantation: Strategies for Hearing Restoration

Strategies to restore sensorineural hearing loss focus on the replacement of lost hair cells, the specialized mechanoreceptors in the organ of Corti that convert the mechanical energy of sound into electrical energy. Hair cells in mammalian systems do not have the capacity to regenerate, but two exciting lines of research hold promise in restoring inner ear function. Here we review basic principles of gene therapy and discuss its application in the inner ear. We survey the various viral vectors and routes of delivery into the inner ear. Applications of gene therapy in the inner include hair cell protection in the face of chemical or noise-induced ototoxicity, spiral ganglion cell survival following hair cell death or injury, and hair cell regeneration. More recently, the viability of gene therapy in human inner ear tissue has been reported. Transplantation of progenitor cells that can differentiate into functioning hair cells with the appropriate connections to their corresponding spiral ganglion cells is yet another strategy to restore sensorineural hearing loss. Neonatal or embryonic stem cells, adult mouse inner ear stem cells, and stem cells from the central nervous system have been shown to differentiate into cells containing hair cell markers and proteins. Prospects for stem cell therapy in the inner ear, and its limitations, will also be examined.

Imaging Prevalence of Sigmoid Sinus Dehiscence among Patients with and without Pulsatile Tinnitus

Objective Define the radiographic prevalence of sigmoid sinus diverticulum or dehiscence (SSDD) in patients with and without pulsatile tinnitus (PT). Study Design Case series with chart review. Setting Tertiary care university medical center. Subjects Patients imaged between January 1, 2003, and December 31, 2012. Methods Two groups were evaluated for SSDD. The first (“PT”) included patients whose radiology report indicated a clinical history of PT (n = 37 symptomatic ears in 30 patients). The second (“non-PT”) included all patients undergoing temporal bone high resolution CT (HRCT) between November 2011 and November 2012 (n = 308 ears in 164 patients) for reasons other than pulsatile tinnitus. Primary outcome measure was the radiographic presence of SSDD. Covariates including age, gender, body mass index (BMI), and audiometric data were analyzed by independent t tests and Fisher’s exact test. Results Within the PT group, SSDD was identified in 24% of ears (9/37) and 23% of patients (7/30); all SSDD patients were female (P = .024). Patients with SSDD were significantly younger (P = .037). SSDD more frequently caused objective tinnitus (P = .016). There was no difference in average BMI between those with and those without SSDD. In the non-PT group, SSDD was identified in 2 (both female) of 164 patients (1.2%; 0.6% of ears). The difference in SSDD prevalence between groups was significant (P < .0001). Conclusions The prevalence of SSDD in patients with PT was 23%. Among patients with PT, those with SSDD were younger, exclusively female, and presented with objective tinnitus. The prevalence of SSDD among asymptomatic patients in 1 year was 1.2%.

Microvascular decompression of the vestibulocochlear nerve for disabling positional vertigo: The house ear clinic experience

Objective To review characteristics of and outcome in patients undergoing microvascular decompression of the vestibulocochlear nerve. Patients studied had a diagnosis of disabling positional vertigo caused by a vascular loop compressing the VIIIth cranial nerve. Study Design Retrospective chart review and telephone interview. Setting Private practice tertiary neurotologic referral center. Patients Twenty patients with disabling positional vertigo underwent 25 retrosigmoid craniotomies for microvascular decompression between November 1990 and June 1999. The 4 men and 16 women ranged in age from 30 to 71 years (mean age, 46 yr). Main Outcome Measures Charts were reviewed and patients were contacted by telephone and asked to rate severity of symptoms (tinnitus and dizziness) on a 4-point scale (none = 1, mild = 2, moderate = 3, and severe = 4) before and after surgery. They were also asked to rate their overall disability from their symptoms on the six-point scale established by the American Academy of Otolaryngology–Head and Neck Surgery. Preoperative and postoperative four-frequency (500 Hz, 1 kHz, 2 kHz, and 4 kHz) pure-tone average and speech discrimination scores were calculated and compared. Complications of surgery are also reported. Results Postoperative tinnitus score and dizziness score showed significant improvement from preoperative scores (p ≤ 0.047 and p ≤ 0.001, respectively), with 80% of patients improved in dizziness rating; 85% improved in their overall disability rating, and the difference from preoperative to postoperative was significant (p ≤ 0.001). The mean postoperative pure-tone averages (15.4 dB) and speech discrimination scores (99%) did not differ from preoperative scores (11.9 dB and 98%). One patient lost all vestibular function in the operated ear (hearing remained intact) as the only complication of surgery. When asked, 83% of patients responded that they would have the surgery again. Conclusions Diagnosing disabling positional vertigo secondary to vascular compression of the VIIIth cranial nerve remains the clinical challenge; a clear history plus air-contrast computed tomographic or magnetic resonance imaging make the diagnosis. Microvascular decompression of the vestibulocochlear nerve is a safe and effective operation for these carefully selected patients.

An in vitro model system to study gene therapy in the human inner ear.

The confined fluid-filled labyrinth of the human inner ear presents an opportunity for introduction of gene therapy reagents designed to treat hearing and balance dysfunction. Here we present a novel model system derived from the sensory epithelia of human vestibular organs and show that the tissue can survive up to 5 days in vitro. We generated organotypic cultures from 26 human sensory epithelia excised at the time of labyrinthectomy for intractable Menieres disease or vestibular schwannoma. We applied multiply deleted adenoviral vectors at titers between 105 and 108 viral particles/ml directly to the cultures for 4–24 h and examined the tissue 12–96 h post-transfection. We noted robust expression of the exogenous transgene, green fluorescent protein (GFP), in hair cells and supporting cells suggesting both were targets of adenoviral transfection. We also transfected cultures with a vector that carried the genes for GFP and KCNQ4, a potassium channel subunit that causes dominant-progressive hearing loss when mutated. We noted a positive correlation between GFP fluorescence and KCNQ4 immunolocalization. We conclude that our in vitro model system presents a novel and effective experimental paradigm for evaluation of gene therapy reagents designed to restore cellular function in patients who suffer from inner ear disorders.

Magnetic Resonance Imaging in the Early Diagnosis of Group A β Streptococcal Necrotizing Fasciitis: A Case Report

Early diagnosis of invasive group A beta streptococcal (GABS) infection has been achieved in a patient using magnetic resonance imaging (MRI) complemented by needle aspiration. Life-saving treatments of GABS infection that include immediate surgical debridement along with the administration of i.v. antibiotics, gamma globulin, and hyperbaric oxygen were then implemented successfully to prevent the development of streptococcal toxic shock syndrome. While MRI is valuable in making early diagnosis of GABS, it should not delay surgical intervention.

Revision aural atresia surgery: indications and outcomes.

Objective: To determine the most common indications for revision congenital aural atresia (CAA) surgery and the postoperative healing and hearing outcomes of revision surgery. Study Design: Retrospective case review. Setting: Tertiary care academic otologic practice. Patients: Patients undergoing revision surgery for CAA. Intervention: Revision surgery for CAA. Main Outcome Measures: Indications for revision atresiaplasty, time to revision surgery, postoperative external auditory canal (EAC) patency, incidence of chronic drainage and/or infection, and postoperative speech reception thresholds (SRTs), and air-bone gaps. Results: Indications for 75 ears (69 patients) undergoing 107 revision operations for CAA included 58% for EAC stenosis, 19% for chronic drainage and/or infection, and 20% for conductive hearing loss (CHL) alone. Fifty ears (67%) required a single revision. Twenty-five ears (33%) required more than 1 revision. With follow-up longer than 3 months (mean, 41 mo), 69% of ears revised for EAC stenosis achieved a patent canal (29% required >1 revision); 75% of ears revised for chronic drainage and/or infection (mean follow-up, 53 mo) realized a dry canal (22% required >1 revision). For all revision surgeries with adequate follow-up (n = 80), the mean postoperative short-term SRT of 24 dB HL was a significant improvement from the mean preoperative SRT of 39 dB HL (p < 0.01, paired t test). Conclusion: EAC stenosis is the most common indication for revision atresiaplasty. Despite the challenges of revision surgery, improvement in canal patency, epithelialization, and hearing utcomes can be achieved.

Gene Transfer in Human Vestibular Epithelia and the Prospects for Inner Ear Gene Therapy

Transfer of exogenous genetic material into the mammalian inner ear using viral vectors has been characterized over the last decade. A number of different viral vectors have been shown to transfect the varying cell types of the nonprimate mammalian inner ear. Several routes of delivery have been identified for introduction of vectors into the inner ear while minimizing injury to existing structures and at the same time ensuring widespread distribution of the agent throughout the cochlea and the rest of the inner ear.