The Kresge Hearing Research Institute-3 (KHRI-3) antibody binds to a guinea pig inner ear supporting cell antigen (IESCA) and causes hearing loss. To gain insight into the mechanism of antibody-induced hearing loss, we used antibody immunoaffinity purification to isolate the IESCA, which was then sequenced by mass spectroscopy, revealing 10 guinea pig peptides identical to sequences in human choline transporter-like protein 2 (CTL2). Full-length CTL2 cDNA sequenced from guinea pig inner ear has 85.9% identity with the human cDNA. Consistent with its expression on the surface of supporting cells in the inner ear, CTL2 contains 10 predicted membrane-spanning regions with multiple N-glycosylation sites. The 68 and 72 kDa molecular forms of inner ear CTL2 are distinguished by sialic acid modification of the carbohydrate. The KHRI-3 antibody binds to an N-linked carbohydrate on CTL2 and presumably damages the organ of Corti by blocking the transporter function of this molecule. CTL2 mRNA and protein are abundantly expressed in human inner ear. Sera from patients with autoimmune hearing loss bind to guinea pig inner ear with the same pattern as CTL2 antibodies. Thus, CTL2 is a possible target of autoimmune hearing loss in humans.

Background: The use of intratympanic (IT) steroids for the treatment of inner ear disorders is promising, but the clinical challenges of prolonged middle ear drug application have proven burdensome, and a sustainable delivery system is yet to be developed. Method: In this study, a guinea pig model was used to determine if dexamethasone in combination with a hyaluronic-acid (HA)-based hydrogel is an efficient, stable and sustainable dexamethasone delivery system to the inner ear. For each animal, right and left middle ear bullae were randomly selected to be filled with dexamethasone alone or dexamethasone-HA (Dex-HA) gel. Perilymph samples were collected at different time points and dexamethasone levels were determined using an ELISA. Results: Dexamethasone was measurable in the perilymph samples up to 72 h after treatment. At 24 h after treatment, the perilymph dexamethasone concentrations were significantly higher (p = 0.01) in the ears treated with Dex-HA gel than in those treated with dexamethasone alone. While the perilymph dexamethasone concentration had decreased at 48 h after treatment with Dex-HA gel, the levels were still higher than those observed at 24 h in ears treated with dexamethasone alone. A high variability in dexamethasone concentration was observed between the samples, and the variability between matched ears receiving different treatments was remarkably lower than the variability within each treatment group, suggesting that individual parameters might play a major role in perilymph dexamethasone concentration. There was no statistically significant correlation between dexamethasone concentration and sex, weight or laterality. Conclusions: Our results show that the Dex-HA gel used in this study provides an effective and sustained dexamethasone release mechanism that might be utilized to treat conditions such as sudden sensorineural hearing loss. This could potentially reduce the morbidity and costs associated with IT treatment.

Objective: To discuss the current management options for giant-cell tumors (GCTs) involving the temporal bone and present two case reports and a review of the literature. Method: In a tertiary-care academic medical center, two patients with GCTs of the temporal bone were evaluated and managed. The patients underwent gross total resection and curettage of GCTs involving the temporal bone. Afterward, both patients were evaluated for postoperative complications as well as for recurrence. Results: Two patients underwent operative excision using curettage. Clinical and radiographic studies demonstrated no evidence of recurrence with 3 years of follow-up in one patient and 10 years of follow-up in the second patient. Conclusion: Based on these results, we concluded that gross total removal and curettage of GCTs in the temporal bone is a viable treatment option. This finding is contrary to previous studies. KEYWORDS:Temporal bone, giant-cell tumors, skull base Giant-cell tumors (GCTs) are rare lesions of the temporal bone that are most commonly found at the epiphysis of long bones.1 Two percent of these lesions present in the head and neck, with the most common sites being the sphenoid, ethmoid, and temporal bones.2 The senior author has treated two patients with GCTs involving the temporal bone with long-term follow-up. This article describes their presentation, diagnostic workup, treatment, and follow-up, as well as provides a review of the literature. CASE 1A 42-year-old man presented to an outside physician with a long history of reduced hearing in the right ear. The patient reported progressive deterioration over the last 3 years, and, in the year before presentation, he noted complete loss of useful hearing in his right ear. The patient denied headache, otalgia, facial pain, trismus, facial weakness, and paresthesias. He denied vision changes, difficulty with swallowing and speech, and changes in voice.

The advantages of rigid fixation in adult craniofacial surgery are well documented, and implanted hardware is not routinely removed unless specifically indicated. There is a tendency, however, to remove hardware in children because of concerns with growth restriction, plate migration, and the lack of information on the fate of miniplates when used in pediatric craniofacial surgery. It has been our practice during the past decade not to remove hardware in children unless specifically indicated. Our study included a total of 121 procedures in 96 children, with an average age of 3.9 years and an average follow-up of 5 years. We placed 375 titanium plates and 1944 screws from 3 manufacturers. Complications encountered in children with titanium plates were as follows: 5 cases of delayed growth and 1 instance of restricted growth, 4 screw migrations (none intracranial), 9 palpable plates causing pain, 3 fluid accumulations over plates, 2 cases of meningitis, and 8 instances of plate and screw removal from the above complications. Twenty-two of 96 patients (23%) had a total of 27 complications from 121 procedures (22%). There were 6 cases in which pain precipitated removal of hardware, 1 case of an excessively mobile plate, and 1 case of documented growth restriction requiring removal; therefore our overall reoperation rate for plate removal was 8%, with no intracranial plate or screw migration.

Laser myringoplasty using a KTP laser for pars tensa atelectasis appears to be beneficial in selected patients. Patients should be followed closely for early tube extrusion and recurrent disease.