Imaging Optimization of Temporal Bones With Cochlear Implant Using a High-resolution Cone Beam CT and the Corresponding Effective Dose.

OBJECTIVE: To evaluate the impact of tube voltage, tube current, pulse number, and magnification factor on the image quality of a novel experimental set-up and the corresponding radiation. MATERIALS AND METHODS: Six human temporal bones with cochlear implant were imaged using various tube voltages, tube currents, pulse numbers, and magnification. The effect of radiation was evaluated using a metaloxide semiconductor field-effect transistor (MOSFET) dosimeter device on an anthropomorphic RANDO RAN102 male head phantom. A copper and aluminum combination filter was used for hardware filtration. RESULTS: Overall, 900 frames, 11 mA, and 88 kV provided the best image quality. In temporal bones imaged with the optimized parameters, the cochlea, osseous spiral lamina, modiolus, stapes, round window niche, and oval window landmarks were demonstrated with anatomic structures still fully assessable in all parts and acceptable image quality. The most dominant contributor to the effective dose was bone marrow (36%-37 %) followed by brain (34%-36%), remainder tissues (12%), extra-thoracic airways (7%), and oral mucosa (5%). CONCLUSIONS: By increasing the number of frames, the image quality of the inner ear details obtained using the novel cone-beam computed tomography improved.

Assessment of radiation-induced otitis media in patients with parotid gland malignancy.

BACKGROUND: Otitis media with effusion (OME) is a known side effect of radiation therapy in patients with head and neck cancer. AIMS/OBJECTIVES: To investigate the incidence rate and clinical course of radiation-induced OME, we have reported on the long-term characteristics of OME in patients with parotid gland malignancy. MATERIAL AND METHODS: This cohort study assessed 200 patients who underwent post-parotidectomy radiation therapy from January 2010 to December 2019 in a tertiary referral center. Postoperative radiation therapy was performed at 6 weeks post-surgery. Serial magnetic resonance images were collected to detect otitis media. Two blinded otologists individually assessed data from radiation therapy initiation to 36 months of post-radiation therapy. RESULTS: A total of 121 patients were enrolled (male, 61 [50.4%]; mean age, 46.98 ± 15.69 years), of which 14 developed otitis media (11.6%) within 6 months after radiation therapy. Spontaneous remission occurred without intervention within 1 year, excluding one patient who sustained otitis media for 2 years. CONCLUSIONS AND SIGNIFICANCE: Radiation-induced OME occurred in 11.6% of patients and it remitted within 1 year without intervention. Therefore, cooperation between otolaryngologists and radiation oncologists is required and invasive intervention should be considered with careful risk-benefit evaluation.

Treatment and outcome of advanced external auditory canal and middle ear squamous cell carcinoma.

This is a retrospective study to evaluate the outcomes and complications of combined treatment, surgery with or without adjunctive intraoperative radiotherapy, of locally advanced temporal bone squamous cell carcinoma. A series of 17 patients with locally advanced squamous cell carcinoma of the temporal bone were treated between September 2002 and February 2007. Eleven patients had primary tumors, and 6 patients had recurrences. According to the University of Pittsburgh staging system, 5 patients were stage II (T2 N0), 6 patients were stage III (5, T3 N0 and 1, T1 N1), and 6 patients were stage IV (5, T3 N2b and 1, T4 N0). All patients underwent lateral temporal bone resection and pedicle flap reconstruction. Eight patients received intraoperative and postoperative radiotherapies, 4 patients underwent postoperative radiation alone, whereas 5 patients did not receive any adjunctive treatment. Median follow-up was 29.5 months. No major complications were observed. No patients were found to have residual gross tumor. Disease-free survival was 73.3%, and overall survival was 75.6%. Radical external auditory canal and/or middle ear canal resection is of utmost importance to obtain a good surgical outcome. Postoperative radiotherapy is necessary to obtain good local control; no major adverse effects were observed in the intraoperative radiotherapy patients. The incidence of major complication is minimal after pedicle flap reconstruction.

Ototoxicity after radiotherapy for head and neck tumors.

PURPOSE: To investigate the incidence of radiation-induced ototoxicity according to the total dose delivered to specific parts of the auditory system, fractionation, and chemotherapy. METHODS AND MATERIALS: Records of 325 patients treated for primary extracranial head and neck tumors with curative intent who received radiotherapy between 1964 and 2000 (median follow-up, 5.4 years) were retrospectively reviewed. Reconstructions of the treatment plans were generated to estimate the doses received by components of the auditory system. RESULTS: Radiotherapy-induced morbidity developed in 41.8% of patients (external ear, 33.2%; middle ear, 28.6%; and inner ear, 26.8%). Univariate/multivariate analyses indicate that total dose received by parts of the auditory system seem to be significant, though fractionation and chemoradiation may contribute to the incidence of ototoxicities. Sensorineural hearing loss (SNHL) was observed in 49 patients (15.1%). Univariate and multivariate analyses indicated that age (p = 0.0177 and p = 0.005) and dose to cochlea (p < 0.0001 and p < 0.0001) were significant, and chemoradiation (p = 0.0281 and p = 0.006) may increase the incidence of SNHL. Five-year and 10-year actuarial risk of clinically overt SNHL increased to 37% (p > 0.0001) above doses of 60.5 Gy compared to 3% at doses below 60.5 Gy. For patients treated with adjuvant chemotherapy, clinically overt SNHL increased to 30% compared to 18% in the no-chemotherapy group at 10 years (p = 0.0281). CONCLUSION: Radiotherapy toxicity was observed in all parts of the auditory system with median doses for incidence varying between 60 Gy to 66 Gy. Total dose to organ seems to be a significant factor though fractionation and chemo-radiation may contribute to ototoxicities.

Analysis of anatomical factors controlling the morbidity of radiation-induced otitis media with effusion.

PURPOSE: To analyze the anatomical factors controlling the morbidity of radiation-induced otitis media with effusion (OME) and determine how to best preserve middle ear function when treating nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: Forty patients with nasopharyngeal carcinoma undergoing 3-D radiotherapy (RT) planning and curative RT were analyzed retrospectively. The difference in dosage over the middle ear cavity and the isthmus of the Eustachian tube (ET) was evaluated. Pure tone audiometry and impedance audiometry tests were performed before and after RT. RESULTS: Mean dosages over the isthmus of the ET for acoustic impedance and pure tone audiometry were recorded. Differences in dosage among the three classifications of unchanged, improved, and worsened ears were statistically significant. CONCLUSION: There was a correlation between the morbidity of radiation-induced OME and the radiation dosage over the middle ear cavities. Decreased OME morbidity was observed when the dosage over the isthmus of the ET was below 52 Gy and the dosage over middle ear cavity was below 46 Gy.

High-resolution numerical model of the middle and inner ear for a detailed analysis of radio frequency absorption.

In order to enable a detailed analysis of radio frequency (RF) absorption in the human middle and inner ear organs, a numerical model of these organs was developed at a spatial resolution of 0.1 mm, based on a real human tissue sample. The dielectric properties of the liquids (perilymph and endolymph) inside the bony labyrinth were measured on samples of ten freshly deceased humans. After inserting this model into a commercially available numerical head model, FDTD-based computations for exposure scenarios with generic models of handheld devices operated close to the head in the frequency range 400-3700 MHz were carried out. For typical output power values of real handheld mobile communication devices the obtained results showed only very small amounts of absorbed RF power in the middle and inner ear organs. Highest absorption in the middle and inner ear was found for the 400 MHz irradiation. In this case, the RF power absorbed inside the labyrinth and the vestibulocochlear nerve was as low as 166 microW and 12 microW, respectively, when considering a device of 500 mW output power operated close to the ear. For typical mobile phone frequencies (900 MHz and 1850 MHz) and output power values (250 mW and 125 mW) the corresponding values of absorbed RF power were found to be more than one order of magnitude lower than the values given above. These results indicate that temperature-related biologically relevant effects on the middle and inner ear, induced by the RF emissions of typical handheld mobile communication devices, are unlikely.

Primary radical radiotherapy for squamous cell carcinoma of the middle ear and external auditory cana--an historical series.

AIMS: To evaluate patients treated with radical radiotherapy alone for squamous cell carcinoma of the middle ear (MEC) and external auditory canal (EAC) in terms of freedom from local recurrence, cancer-specific survival and morbidity. MATERIALS AND METHODS: Between 1965 and 1988, 123 patients were treated, 70 with MEC and 53 with EAC. The median age was 64 years (range 21-86) and 78% presented as late stage. The median dose was 55 Gy (range 39-55) in 16 once daily fractions (range 13-21). RESULTS: At 5 and 10 years, respectively, freedom from local recurrence was 56 and 56%, disease-free survival was 45 and 43%, cancer-specific survival was 53 and 51%, and overall survival was 40 and 21%. Cancer-specific survival was significantly worse with late stage as opposed to early stage (P = 0.0026), as was local recurrence (P = 0.0088). No differences in survival and local control were seen according to site. Radionecrosis developed in 6% of patients. CONCLUSIONS: Combined treatment using radiotherapy and radical surgery is often favoured. This large series shows that radical radiotherapy achieves comparable results in terms of local control and cancer-specific survival. Our radiotherapy regimen is now 55 Gy in 20 daily fractions to reduce late morbidity. Radiotherapy alone remains a viable option, especially as morbidity can be minimised and target volume delineation optimised using computer planning in the future.

Epithelial internalization of superparamagnetic nanoparticles and response to external magnetic field.

Superparamagnetic magnetite nanoparticles (MNP) coated with silica were synthesized and chronically implanted into the middle ear epithelial tissues of a guinea pig model (n=16) for the generation of force by an external magnetic field. In vivo limitations of biocompatibility include particle morphology, size distribution, composition and mode of internalization. Synthesis of MNP was performed using a modified precipitation technique and they were characterized by transmission electron microscopy, X-ray diffractometry and energy dispersive spectroscopy, which verified size distribution, composition and silica encapsulation. The mechanism for internalizing 16+/-2.3 nm diameter MNP was likely endocytosis, enhanced by magnetically force. Using sterile technique, middle ear epithelia of tympanic membrane or ossicles was exposed and a suspension of particles with fluoroscein isothiocyanate (FITC) label applied to the surface. A rare earth, NdFeBo magnet (0.35 T) placed under the animal, was used to pull the MNP into the tissue. After 8 days, following euthanasia, tissues were harvested and confocal scanning laser interferometry was used to verify intracellular MNP. Displacements of the osscicular chain in response to an external sinusoidal electromagnetic field were also measured using laser Doppler interferometry. We showed for the first time a physiologically relevant, biomechanical function, produced by MNP responding to a magnetic field.

Age and Gender Effects on Wideband Absorbance in Adults With Normal Outer and Middle Ear Function.

PURPOSE: This study examined the effects of age and gender on wideband energy absorbance in adults with normal middle ear function. METHOD: Forty young adults (14 men, 26 women, aged 20-38 years), 31 middle-aged adults (16 men, 15 women, aged 42-64 years), and 30 older adults (20 men, 10 women, aged 65-82 years) were assessed. Energy absorbance (EA) data were collected at 30 frequencies using a prototype commercial instrument developed by Interacoustics. RESULTS: Results showed that the young adult group had significantly lower EA (between 400 and 560 Hz) than the middle-aged group. However, the middle-aged group showed significantly lower EA (between 2240 and 5040 Hz) than the young adult group. In addition, the older adult group had significantly lower EA than the young adult group (between 2520 and 5040 Hz). No significant difference in EA was found at any frequency between middle-aged and older adults. Across age groups, gender differences were found with men having significantly higher EA values than women at lower frequencies, whereas women had significantly higher EA at higher frequencies. CONCLUSIONS: This study provides evidence of the influence of gender and age on EA in adults with normal outer and middle ear function. These findings support the importance of establishing age- and gender-specific EA norms for the adult population.

Radiotherapy-induced ear toxicity.

Despite their particular functional consequences, radiotherapy-induced ear injuries remain under-evaluated and under-reported. These reactions may have acute or late character, may affect all structures of the hearing organ, and result in conductive, sensorineural or mixed hearing loss. Up to 40% of patients have acute middle ear side effects during radical irradiation including acoustic structures and about one-third of patients develop late sensorineural hearing loss (SNHL). Total radiotherapy dose and tumour site seem to be among the most important factors associated with the risk of hearing impairment. Thus, reduction in radiation dose to the auditory structures should be attempted whenever possible. New radiotherapy techniques (3-dimensional conformal irradiation, intensity modulated radiotherapy, proton therapy) allow better dose distribution with lower dose to the non-target organs. Treatment of acute and late external otitis is mainly conservative and includes the anti-inflammatory agents (applied topically and systematically). Post-radiation chronic otitis media and the eustachian tube pathology may be managed with tympanic membrane incision with insertion of a tympanostomy tube (grommet), although the benefit of such approach is controversial and some authors advocate a more conservative approach. In these patients the functional deficit can be alleviated by application of bone conduction hearing aids such as, e.g., the bone anchored hearing aid (BAHA). There is no standard therapy for post-irradiation sudden or progressive SNHL yet corticosteroid therapy, rheologic medications, hyperbaric oxygen or carbogen therapy are usually employed (as for idiopathic SNHL), although controversial data on the efficacy of these treatment modalities have been published. In selected cases with bilateral profound hearing loss or total deafness, cochlear implants may prove effective. Further improvements in radiotherapy techniques and progress in otologic diagnostics and therapy may allow better prevention and management of radiation-related acoustic injury.

Radiation-induced otitis media--study of a new test, vestibular-evoked myogenic potential.

PURPOSE: Excluding the radiation history, current physical examination and audiovestibular function tests fail to differentiate radiation-induced otitis media (ROM) from chronic otitis media (COM). This study applied the newly developed vestibular-evoked myogenic potential (VEMP) test to investigate whether the VEMP test can be of help in differentiating between them. METHODS AND MATERIALS: Fourteen irradiated nasopharyngeal carcinoma (NPC) patients with ROM (18 ears) and 14 age-matched, and gender-matched patients with COM (18 ears) were enrolled. Each patient underwent stimulation with a short tone burst initially, and then by tapping the forehead using a tendon hammer. To define the effect of the neck soft tissue on the VEMP response further, an additional two groups (10 non-NPC patients with ROM but no neck fibrosis/edema and 10 non-NPC patients without ROM but with neck fibrosis/edema) were included for comparison. RESULTS: The occurrence of normal VEMPs in the ROM ears (33%) did not differ significantly from that in the COM ears (56%) by tone-burst stimulation. However, using tapping evocation, most (89%) COM ears revealed normal VEMPs, and most (61%) ROM ears demonstrated delayed VEMPs. Furthermore, most (90%) non-NPC patients with ROM but no neck fibrosis/edema revealed delayed or absent VEMPs. In contrast, all non-NPC patients with neck fibrosis/edema but no ROM demonstrated normal VEMPs bilaterally, implying that the effect of neck soft tissue on the VEMP response is less. CONCLUSION: Through tapping evocation, most COM ears revealed normal VEMPs, and most ROM ears demonstrated delayed VEMPs, indicating that ROM is different from COM because of the larger affected areas such as retrolabyrinthine or brainstem involvement. This result can explain why grommet insertion or tympanoplasty is not beneficial to postirradiated ears, possibly because both operations spare the inflammation outside the middle ear cavity.

Delayed effects of ionizing radiation on the ear.

The question of damage to the ear from exposure to ionizing radiation was addressed by exposing groups of chinchillas to fractioned doses of radiation (2 Gy per day) for total doses ranging from 40 to 90 Gy. In order to allow any delayed effects of radiation to become manifest, the animals were sacrificed two years after completion of treatment and their temporal bones were prepared for microscopic examination. The most pronounced effect of treatment was degeneration of sensory and supporting cells and loss of eighth nerve fibers in the organ of Corti. Damage increased with increasing dose of radiation. The degree of damage found in many of these ears was of sufficient magnitude to produce a permanent sensorineural hearing loss.

Acute effects of irradiation on middle ear mucosa.

Single field, fixed irradiation of bilateral tympanic cavities using 200-kV x-rays was administered to five guinea pigs. The irradiation dose was 30 Gy. They were killed immediately after irradiation, and bilateral middle ear mucosa was examined for ciliary activity and epithelial structure. Significant deterioration of the ciliary activity in the middle ear mucosa was observed, proximal as well as distal to the eustachian tube. Electron microscopy showed various changes in the irradiated middle ear mucosa. The most conspicuous findings were hyperreactivity in secretion, vacuolation of ciliated cells, and stomal edema.

Long-term post-irradiation middle ear effusion in nasopharyngeal carcinoma.

This study aimed to find out if there were factors which influenced the development of long-term middle ear effusion (MEE) in patients irradiated for nasopharyngeal carcinoma. Thirty-five patients (70 ears) were studied for 2-8 years (mean 5.5 years) post-radiotherapy. The factors studied were (a) sex (b) age (c) tumour size and (d) presence of pre-radiotherapy MEE. Only the presence of pre-radiotherapy MEE was found to be statistically significant (P = 0.004, Fisher's exact test). Stepwise multiple regression analysis showed the presence of pre-radiotherapy MEE was a predictor of post-radiotherapy MEE with an odds ratio of 0.67. It is postulated that irreversible Eustachian tube dysfunction occurs when the tube which has been damaged by tumour is further damaged by irradiation. This may explain the frequent persistent otorrhea when ventilation tubes are used to treat post-radiotherapy MEE in patients with nasopharyngeal carcinoma. In conclusion, an ear with pre-irradiation MEE was almost seven times more likely to have long-term post-irradiation MEE than an ear without pre-irradiation MEE.

Delayed ultrastructural radiation induced changes in the human mesotympanic middle ear mucosa.

The irradiation-induced changes in the middle ear mucosa of six patients were described and discussed. The epithelium showed marked reduction of the cytoplasmic mass, variable degrees of ciliary loss and widening of the intercellular spaces with disruption of some of the maculae adherentes. The connective tissue stroma showed increased production of collagenous fibrous tissue and increased number of synthetically active fibroblasts. New gland formation has been observed and the glands exhibited reduced activity. The endothelial cells of some blood capillaries were swollen and the basal lamina was duplicated. The lumina of other capillaries were completely obliterated and replaced by a cord of fibrous tissue.

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: X. Results of ear examination.

In the five pocket mice flown on Apollo XVII, no evidence was found that the inner ear had been damaged, though poor fixation precluded detailed study. On the other hand, the middle ear cavity was involved in all the mice, hemorrhage having occurrred in response to excursions in pressure within the canister that housed the mice during their flight. The same occurred in flight control mice which had been subjected to pressure excursions of much the same magnitude. A greater degree of exudation into air cells and greater leukotaxis were noted in the flight animals than in the control animals. There was no increase in leukocyte population along the paths of the 23 cosmic ray particles registered in the subscalp dosimeters that traversed the middle ear cavities of the flight mice. The increased exudation and the greater response by leukocytes in the flight mice may have been causally related to the lesions found in their olfactory mucosa but there were no data in support of this possibility.

[The results of treatment of middle ear carcinoma with radiotherapy]. / Wyniki leczenia napromienianiem chorych na raka ucha srodkowego.

We have described results of treatment patients with an extremely rare disease--a middle ear carcinoma. Through 25 years we have treated 37 patients. We recommend surgical treatment immediately supplemented by radiotherapy--because of anatomical difficulties in gaining enough histological margins. The median of survival time was 7 months in the group of palliatively treated patients and 14 months in the group of radically treated patients. Three patients had following complications: a necrosis of retromandibular space and mandibular joint, a purulent otitis media and an osteoporosis of the temporal bone.

[The role of radiotherapy in the combined treatment of cancer of the middle ear]. / Rola radioterapii w skojarzonym leczeniu raka ucha srodkowego.

The results of treatment of 26 patients with the middle ear cancer were evaluated. Manifestation of the disease is not specific, so it is often diagnosed only in advanced stages. 16 patients were radically treated, 15 of them by radiotherapy and surgery. They received the dose of 60 Gy in 20-30 fractions of megavoltage therapy, with use of oblique beam technique with wedge filters. 10 patients were irradiated with palliative intention. Estimated 5-years survival in radically treated patients equals 47%. Other reports and own observations advocate combined treatment: surgery and irradiation for cancer of the middle ear.

[Malignant neoplasms of the middle ear in Krakow Otolaryngological Clinic in the years 1962-1994]. / Nowotwory zlosliwe ucha srodkowego w materiale Krakowskiej Kliniki Otolaryngologicznej w latach 1962-1994.

In the years 1962-1994, 20 patients were treated with a surgery because of malignant neoplasms of the middle ear. Pathomorphological examination showed rhabdomyosarcoma and squamous carcinoma. After surgery patients were treated supplementary Rtg-th. As a results of treatment 45% asymptomatic 5-years long survivals. A considerable advancement of the disease, late diagnosis and resulting from it nonradicality of the surgery influenced the results. Other reports and own observation advocate combined treatment: surgery and irradiation for radiosensitive malignant neoplasms of the middle ear.

[Middle ear adenoma: a case report]. / Przypadek gruczolaka ucha srodkowego.

Middle ear adenoma (MEA) is a rare neoplasm with benign clinical behavior. The immunohistochemical and ultrastructural studies revealed the mixed, bidirectional mucinous and neuroendocrine character. These tumors have been known by many different names, reflecting the controversies relating to their histogenesis and differentiation. The term middle ear adenoma was proposed by Hyams and Michaels in 1976 and since this time over 100 cases were described in the literature. The most often symptoms of the MEA are the unilateral hearing loss and the tinnitus. MEA should be treated by surgery and very attentive postoperative follow-up. The prognosis of these tumors are good. The histological structure of middle ear adenoma, as well as symptomatology, treatment and clinical behavior are discussed on the basis of the literature. A case of histologically confirmed middle ear adenoma in a 34 year old women is presented.