Langerhans Cell Histiocytosis of the Temporal Bone with Otic Capsule Involvement.

INTRODUCTION: This study is conducted to demonstrate that destructive lesions of the otic capsule by Langerhans cell histiocytosis (LCH) causing both radiographic and audiologic findings can be completely reversed with adequate treatment. Retrospective case review and analysis of clinical and imaging data were obtained as part of the diagnosis and treatment of patients with LCH of the temporal bone. METHODS: With Institutional Review Board (IRB) approval, cases of LCH involving the temporal bone were searched for within the institutional databases. Criteria for inclusion was histologic diagnosis of LCH and pretreatment computed tomography (CT) demonstrating temporal bone and/or otic capsule involvement and posttreatment follow-up CT/magnetic resonance imaging (MRI) scans obtained at least 6 months after starting treatment. RESULTS: We report eight cases of LCH of the temporal bone with three demonstrating otic capsule involvement radiographically and/or clinically. Review of posttreatment imaging revealed all three patients had complete restoration of the bony labyrinthine architecture and near or complete restoration of their hearing. CONCLUSIONS: Though LCH of the temporal bone is a common site within the spectrum of the disease, involvement of the otic capsule remains rare. Here, we report the largest series of otic capsule involvement by LCH and investigate whether both architecture and hearing are recovered with appropriate treatment. Lastly, restoration of the bony architecture of the labyrinth suggests the mechanism of LCH is demineralization and not ablative.

Nanoparticle assisted photothermal deformation of individual neuronal organelles and cells.

Stimulation of the localized surface plasmon of metallic nanoparticles has been shown to be an effective mechanism to induce photothermal damage in biological tissues. However, few studies have focused on single cell or subcellular ablation. Our results show that, upon incubation, gold nanostars are internalized by neurons of acute mouse cerebellar brain slices, clustering inside or close to the nucleus. By stimulating the nanostars' surface plasmon using a femtosecond laser, we show deformation of single nuclei and single cells. Given its precision and extremely localized effect, this is a promising technique for photothermal therapy in areas sensitive to collateral thermal damage such as the nervous system.

Implications of sound levels generated by otologic devices.

OBJECTIVE: Exposure to loud noise can result in sensorineural hearing loss. In otology, a wide variety of devices are used that have significant noise output, both to the operator and the patient. This study quantifies and compares the sound pressure levels (SPL) of a variety of otologic instruments. METHODS: Using a calibrated sound pressure level meter, the peak and impulse sound pressure levels of several otologic instruments were determined at 1 cm from their application to human temporal bones. Devices measured were an air-powered drill with a cutting burr, an electric micro-drill, and KTP, CO(2), and erbium lasers. RESULTS: Impulse sound pressure levels for the KTP laser, CO(2) laser, microdrill, air-powered drill and erbium laser were 67, 71, 90, 105, and 105 dBA, respectively. Peak sound pressure levels were 81, 89, 102, 118, and 132 dBA, respectively. CONCLUSIONS: Use of the KTP laser, CO(2) laser, and microdrill result in impulse levels of less than 100 dBA. Although the impulse levels of the erbium laser and the air-powered drill were equivalent, the peak sound pressure levels of the erbium laser were significantly higher. These high sound pressure levels may increase the chance for hearing loss. Like any tool, lasers and drills have benefits and risks. The results of this study demonstrate significant differences in SPLs of common otologic lasers and drills. Although noise-induced hearing loss is a function of both SPL and duration of exposure, surgeons should consider these differences when selecting and applying these tools, especially when used on or adjacent to the ossicular chain and stapes footplate.

Pulsatile tinnitus in patients with morbid obesity: the effectiveness of weight reduction surgery.

BACKGROUND: Morbid obesity is increasing in the United States population. Morbidly obese patients may have disabling pulsatile tinnitus (PT) secondary to pseudotumor cerebri syndrome and often seek treatment from otolaryngologists because of this symptom. OBJECTIVE: To determine the effectiveness of weight reduction surgery (WRS) for relief of PT in patients with morbid obesity. STUDY DESIGN: Retrospective study of morbidly obese patients with associated PT. SETTING: Academic tertiary referral center. PATIENTS: Sixteen women with morbid obesity and associated PT who underwent WRS. RESULTS: Median age was 34 years (range 24-45 years). Average preoperative body mass index was 45 kg/m2 (range 33-70 kg/m2). Average weight loss was 45+/-17 kg (range 25-99 kg). Average postoperative weight was 75+/-14 kg (range 57-105 kg). The average preoperative cerebrospinal fluid pressure was 344+/-103 mm H2O (range 220-520 mm H2O). Postoperative measurements of cerebrospinal fluid, obtained on 4 patients, revealed an average decrease in pressure of 198 mm H2O (range 120-400 mm H2O). Thirteen patients experienced complete resolution of their PT (81%). Three patients continued to have PT despite significant weight reduction. CONCLUSIONS: Weight reduction surgery was effective in relieving PT in morbidly obese patients with associated pseudotumor cerebri syndrome and should be considered when conservative management has failed.

Partial labyrinthectomy with hearing preservation: an experimental study in guinea pigs.

Recent advances in neurotologic surgery have challenged the traditional belief that violating the labyrinth is incompatible with hearing. Our aim in this study was to define the conditions that result in hearing preservation and hearing loss after surgery on the labyrinth. A guinea pig model was developed. Click-evoked auditory brain stem responses were used to determine hearing thresholds. Animals underwent surgical destruction of part or all of the vestibular labyrinth. Transection and plugging of the lateral semicircular canal resulted in normal hearing. Transection of multiple semicircular canals also resulted in hearing preservation. Intentional suctioning of perilymph from a transected canal led to transient hearing loss with complete recovery. Sequential destruction of the entire lateral semicircular canal resulted in preserved hearing as long as the vestibule was not opened. Wide vestibulotomy resulted in hearing loss. Preliminary histologic studies showed that cochlear hair cells were preserved in most cases. The results of our experiments demonstrate the feasibility of preservation of hearing after partial labyrinthectomy and provide physiologic criteria for developing new operations on the inner ear in human subjects.