Menière's disease has an episodic course, and certain patients undergo spontaneous remission of their vertigo. A retrospective study of patients treated from 1974 to 1983 was undertaken to evaluate the long-term outcome of patients with Menière's disease for whom surgery was recommended, comparing those who had a surgical procedure with a similar group of patients who declined surgery. The surgical procedures performed were endolymphatic subarachnoid shunt (ELS), retrolabyrinthine vestibular neurectomy (RVN), middle fossa vestibular neurectomy (MFVN), and transmeatal cochleo-vestibular neurectomy (CVN). We used a questionnaire, made up according to the 1985 American Academy of Otolaryngology (AAO) criteria, for reporting results for Menière's disease treatment, and compared patients who were offered surgery but declined (N = 50) with those who underwent surgery (N = 83). The data were analyzed statistically. Initial evaluation, which included air and bone conduction audiometry, speech discrimination, electronystagmography (ENG), frequency of vertigo attacks per month, and disability, showed both groups to be comparable at the outset. Of the non-operated group 57% had complete control of vertigo at 2 years; 71% had complete control after an average of 8.3 years. After an ELS, 40% of patients had complete control of vertigo after 2 years; 70% had complete control after an average of 8.7 years. After a neurectomy (RVN or CVN), 93% had complete control of vertigo (average followup, 4.4 years). These results indicate statistically that the ELS procedure does not alter the long-term natural course of vertigo control in Menière's disease, whereas both the RVN and CVN significantly improve the patient's chance of being permanently free of vertigo attacks.

Connexin26 (Cx26, GJB2) mutations account for >50% of nonsyndromic hearing loss. The deafness is not always congenital. A large group of these patients (~30%) demonstrate a late-onset hearing loss, starting in childhood. They have normal hearing early in life and are therefore good candidates for applying protective and therapeutic interventions. However, the underlying deafness mechanism is unclear. In this study, we used a time-controlled, inducible gene knockout technique to knockout Cx26 expression in the cochlea after birth. We found that deletion of Cx26 after postnatal day 5 (P5) in mice could lead to late-onset hearing loss. Similar to clinical observations, the mice demonstrated progressive, mild to moderate hearing loss. The hearing loss initiated at high frequencies and then extended to the middle- and low-frequency range. The cochlea showed normal development and had no apparent hair cell loss. However, distortion product otoacoustic emission (DPOAE) was reduced. The reduction was also progressive and large at high-frequencies. Consistent with DPOAE reduction, we found that outer hair cell electromotility associated nonlinear capacitance was shifted to the right and the slope of voltage dependence was reduced. The endocochlear potential was reduced in Cx26 conditional knockout (cKO) mice but the reduction was not associated with progressive hearing loss. These data suggest that Cx26 deficiency may impair active cochlear amplification leading to late-onset hearing loss. Our study also helps develop newer protective and therapeutic interventions to this common nonsyndromic hearing loss.

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The results of 33 small fenestra stapedotomies performed using conventional techniques were compared with the results of 33 stapedotomies performed using the argon or KTP laser. The ossicular chain was reconstructed using a Teflon wire piston of 0.6 mm diameter, and follow-up was at least 1 year. Over-closure of the air-bone gap or closure to within 10 dB was accomplished in 91% of the laser-treated group versus 72% of the conventionally treated group (p less than 0.10). The hearing results were statistically better in the laser group (p less than 0.05). Transient delayed vestibular symptoms, lasting from 1 to 3 weeks, were present in 39% of the laser-treated group and in 12% of the patients treated by conventional techniques (p less than 0.05). The KTP laser stapedotomy, using a micromanipulator mounted on the microscope, is a safe, efficient technique that reduces some of the technical difficulties associated with conventional stapes surgery. The main advantage of the laser is that it enables the surgeon to make an atraumatic, bloodless opening in a fixed or mobile stapes footplate without mechanical manipulation of the stapes. Using a lower wattage to vaporize the footplate and waiting several seconds between laser bursts may decrease the incidence of postoperative vestibular symptoms. The use of the KTP laser in stapes surgery represents a major advance in surgery for otosclerosis.

Digenic Connexin26 (Cx26, GJB2) and Cx30 (GJB6) heterozygous mutations are the second most frequent cause of recessive deafness in humans. However, the underlying deafness mechanism remains unclear. In this study, we created different double Cx26 and Cx30 heterozygous (Cx26+/−/Cx30+/−) mouse models to investigate the underlying pathological changes and deafness mechanism. We found that double Cx26+/−/Cx30+/− heterozygous mice had hearing loss. Endocochlear potential (EP), which is a driving force for hair cells producing auditory receptor current, was reduced. However, unlike Cx26 homozygous knockout (Cx26−/−) mice, the cochlea in Cx26+/−/Cx30+/− mice displayed normal development and had no apparent hair cell degeneration. Gap junctions (GJs) in the cochlea form two independent networks: the epithelial cell GJ network in the organ of Corti and the connective tissue GJ network in the cochlear lateral wall. We further found that double heterozygous deletion of Cx26 and Cx30 in the epithelial cells did not reduce EP and had normal hearing, suggesting that Cx26+/−/Cx30+/− may mainly impair gap junctional functions in the cochlear lateral wall and lead to EP reduction and hearing loss. Most of Cx26 and Cx30 in the cochlear lateral wall co-expressed in the same gap junctional plaques. Moreover, sole Cx26+/− or Cx30+/− heterozygous mice had no hearing loss. These data further suggest that digenic Cx26 and Cx30 mutations may impair heterozygous coupling of Cx26 and Cx30 in the cochlear lateral wall to reduce EP, thereby leading to hearing loss.