Cancer of the external auditory canal and middle ear in Denmark from 1992 to 2001.

BACKGROUND: In the context of the Danish Head and Neck Cancer Group, nationwide material from 1992-2001 was analyzed to study the extent and nature of the disease, evaluate treatment, compare staging systems, and examine prognosis and survival. METHODS: Review of 68 consecutive cases: 47 squamous cell carcinoma, 10 basal cell carcinoma, and 11 other histologies. Moody (modified Pittsburgh) stages were T1 (26), T2 (9), T3 (8), T4 (23), Tx (2). Sixty-four patients were treated with curative intent: 24 primary radiotherapy, 18 primary surgery, and 22 combined. Surgery was limited to tumor excision and mastoidectomy and in 1 case temporal bone excision. RESULTS: Twenty-seven of 28 recurrences involved primary site. Kaplan-Meier analysis showed 5-year locoregional control of 48%, disease-specific survival 57%, and overall survival 44%. CONCLUSION: This nationwide study confirmed that local failure is the main problem, and future improvements should focus on more aggressive local treatment.

Outcome of mobile ear surgery for chronic otitis media in remote areas.

OBJECTIVES: The Inuit of Greenland, Canada and Alaska suffer from chronic otitis media (COM). In Greenland these patients used to be referred to Denmark for ear surgery. This was expensive and unsatisfactory, and the results were poor. A mobile ear surgery project was developed. DESIGN: The study is longitudinal and prospective with follow-up. SUBJECTS AND METHODS: The 274 patients were selected according to severity of COM and hearing loss. Only air conduction (AC) audiometry was obtained. Median age was 27 years and 55% were females. RESULTS: Closure rates at three weeks, one year, and two years were 67 percent, 72 percent, and 76 percent, respectively. Median AC pure tone average improvement was 15 dB and 12 dB after one year and two years, and 73 percent and 67 percent were satisfied. Outcome was associated with quality of the surgical skills (P < 0.002). We found marked spontaneous fluctuations between the follow-ups. CONCLUSION: The results of mobile ear surgery in Greenland are acceptable. Mobile ear surgery may be implemented in areas with limited access to health care, eg, in developing countries.

Intravital microlesions in the human otic capsule. Detection, classification and pathogenetic significance revisited.

PURPOSE OF THE STUDY: To verify microcracks in human temporal bones by a method which distinguishes intravital lesions from artifacts, to revisit previous information derived from decalcified materials on their morphology and classification and to discuss the possible clinical significance. PROCEDURES: Histological analysis of 210 undecalcified adult human temporal bones bulk-stained by basic fuchsin in ethanol prior to embedding in methyl methacrylate and processing by the cutting and grinding method. RESULTS: Intravital crack lesions appeared in all specimens and could be distinguished from artifacts regardless of crack morphology and size. Particularly, large microfissures were found around the labyrinthine windows, while smaller microfissures originating at the perilymphatic space were found throughout perilabyrinthine bone. Small noncommunicating fatigue microdamage was identified for the first time. All lesions were reorganized according to morphology, topography and possible clinical significance. CONCLUSION: Microfissures accumulate in the adult otic capsule as expected when bone remodeling is low. Any capsular microlesion may introduce a possible barrier in the recently discovered antiresorptive signaling pathway from inner ear structures via the lacunocanalicular osteocytic network to perilabyrinthine bone. For this reason intravital microfissures may interfere with in vivo inhibition of temporal bone remodeling and consequently offer another pathogenetic factor in otosclerosis.

Hearing outcomes after mobile ear surgery for chronic otitis media in Greenland.

OBJECTIVES: Chronic otitis media (COM) with hearing loss (HL) occurs frequently in many populations with limited access to specialized treatment. This article reports on the hearing outcomes following mobile ear surgery in Greenland. STUDY DESIGN: The study was longitudinal and prospective with pre- and post-operative followup data compiled at 1- and 2-year intervals. METHODS: Selection criterion included individuals with COM with or without suppuration (CSOM) and with associated HL. Hearing tests were obtained by using a simple air-conduction (AC) audiometry. The median age of the 274 participants was 27 years (8-60 years), and 45% were males. Sixty-one percent had COM and 34% had CSOM. Myringoplasty or tympanoplasty type I was performed in 88% of the cases. RESULTS: The median pre-operative AC pure-tone average was 38 dB. The follow-up rate was 75% and 61% at 1- and 2-years. Hearing gain was found in 78% at both follow-ups and was > or = 10 dB in 62% and 56%, respectively. The median hearing gain was 15 dB and 12 dB, respectively. Independent predictors of hearing gain were pre-operative tympanic membrane atrophy and closure of perforations. CONCLUSIONS: Long-term hearing gain can be achieved with mobile ear surgery and this, in addition to tympanic membrane closure, is important for hearing rehabilitation in populations with poor access to health care.

Dynamic bone studies of the labyrinthine capsule in relation to otosclerosis.

The pathological perilabyrinthine bone remodelling of otosclerosis is associated with a genetic predisposition and triggered by mechanisms so far unknown. A proposed viral aetiology of otosclerosis originates from a similar concept of Paget's disease. However, at present, it is not clear why a virus should cause otosclerosis, confined to the bony otic capsule with no effects on the general skeleton in some patients, and systemic Paget's disease with only occasional involvement of the bony otic capsule in others. Moreover, the extent and distribution of pathological bone remodelling is different in Paget's disease of the temporal bone and in otosclerosis. Bone resorption and consequently bone remodelling which turns over the general skeleton at a rate of 10% per year is normally highly restricted in perilabyrinthine bone to a minimum of 0.13% per year except in otosclerosis, and systemic remodelling rates are normal even in otosclerotic patients. This suggests the existence of a local inner ear mechanism in control of capsular remodelling activity, which is either overruled, bypassed or most likely defective in otosclerosis, no matter what may have triggered the disease process. We present experimental data related to this mechanism, which may offer a truly local pathogenetic factor in otosclerosis.

Acute otitis media and season of birth.

INTRODUCTION: This study examines the question whether season of birth is associated with acute otitis media (AOM) and recurrent AOM (rAOM) and whether season of birth is associated with early age of AOM onset. METHODS: This was done in a population-based survey of 591 unselected Greenlandic children aged 3-5 and 8 years, living in the two largest towns in Greenland. The overall attendance rate was 86%. Information of AOM episodes was obtained from the parents and cross-checked in medical records available for 95% of the children. In total, 67% reported AOM at least once and 30% of those had rAOM. RESULTS: According to season of birth, the frequency of history of AOM in general varied between 63% and 70% lowest for birth in the autumn and highest for birth in the spring but without any significant statistical difference (p=0.51). The similar variation in rAOM according to season of birth was between 21% and 35%, highest for children born in autumn and winter and lowest for children born in the spring (p=0.09). Additionally, there was no difference in age at onset of the first AOM episode according to season of birth. However, AOM children born in the summer and autumn periods have a significantly higher relative risk (RR=1.44, CI=1.04-1.99) of attracting rAOM than AOM children born in the winter and spring periods. This may be due to a higher risk of being quickly reinfected in the late autumn and winter period with another episode of upper respiratory tract infection. CONCLUSION: Season of birth do not seem to be a predictor of AOM episodes or early onset of AOM but children born in the summer and autumn periods who attracts AOM have a higher risk of developing rAOM.

In vivo observation of dynamic perilymph formation using 4.7 T MRI with gadolinium as a tracer.

OBJECTIVE: To investigate the pharmacokinetics of gadolinium in the perilymphatic fluid spaces of the cochlea in vivo using high-resolution MRI to obtain information concerning perilymph formation. MATERIAL AND METHODS: A Bruker Biospec Avance 47/40 experimental MRI system with a magnetic field strength of 4.7 T was used. Anesthetized pigmented guinea pigs were injected with the contrast agent Gd-diethylenetriaminepentaacetic acid-bismethylamide and placed in the magnet. The signal intensity of Gd in the tissues was used as a biomarker for dynamic changes in the perilymphatic fluid. RESULTS: The most rapid uptake of Gd in the perilymphatic fluid spaces occurred in the lower part of the modiolus, followed by the second turn of the scala tympani. Within the scala tympani, the distribution of Gd in the basal turn was significantly lower than that in the other turns. Destruction of the cochlear aqueduct was followed by an increase in Gd uptake in the perilymph instead of a reduction. CONCLUSIONS: These findings offer further evidence that the pervasive perilymphatic fluid derives from the cochlear blood supply via the cochlear glomeruli, which are in close proximity to the scala tympani within the modiolus, and the capillary in the spiral ligament. Cerebrospinal fluid communicates with perilymph via the cochlear aqueduct but is not the main source of perilymph. These findings are of relevance to the treatment of inner ear diseases, as well as to our understanding of the flow and source of perilymphatic fluid.

Comparison of the protective efficacy of neurotrophins and antioxidants for vibration-induced trauma.

BACKGROUND: Patients undergoing temporal bone surgery or subjects working with vibrating tools may develop vibration-induced hearing loss (VHL). The aim of this study was to characterize the effects of pretreatment with N-acetylcysteine (NAC) or the neurotrophic factors, brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF), on VHL in an animal model. METHODS: Trauma to the cochlea was created with a vibrating probe placed on the bone of the external ear canal. BDNF and CNTF(Ax1) were delivered into the cochlea with mini-osmotic pumps. NAC was delivered into the cochlea by round window membrane (RWM) injection, by RWM permeation, or by oral administration. Hearing was evaluated with electrocochleography (ECoG). RESULTS: For control animals, vibration resulted in an average immediate threshold shift of 42 +/- 26 dB. NAC provided no protective benefit in animals subjected to VHL, regardless of the delivery method, with average threshold shifts varying from 38 to 56 dB across groups. NAC injection through the round window membrane was toxic, causing a ECoG threshold shift of >25 dB. In BDNF+CNTF(Ax1)-treated animals, immediate hearing loss was similar to that in control animals. There was a trend of threshold recovery by 1 day after vibration; however, the improvement was not statistically significant, nor was there a significant difference in 1-day thresholds across groups. CONCLUSIONS: Local infusion of BDNF and CNTF(Ax1) may enhance the rate of recovery from VHL, compared to control animals. In contrast, NAC had no effect on VHL, and when delivered by RWM injection, was actually toxic to the inner ear.

In vivo visualization of endolymphatic hydrops in guinea pigs: magnetic resonance imaging evaluation at 4.7 tesla.

In order to find out whether it is possible to visualize experimental endolymphatic hydrops in the cochlea with magnetic resonance imaging (MRI) at 4.7 T, we used 11 guinea pigs. Five normal guinea pigs were used as controls. Early manifestation of endolymphatic hydrops was evaluated in endolymphatic sac (ES)-intact animals (n = 6), and advanced manifestation in ES-damaged animals (n = 5) by means of MRI with gadolinium-diethylenetriaminepentaacetate-bismethylamide (Gd-DTPA-BMA) contrast agent. Hearing was tested with electrocochleography. The surface area of 3 partitions of the cochlea was used to quantify endolymphatic hydrops. The fine structure of the 3 partitions of the cochlea was visualized with MRI in all animals, as Gd-DTPA-BMA appeared mainly in the scala tympani and scala vestibuli. As early as 5 days after endolymphatic sac surgery, endolymphatic hydrops started to appear as visualized by MRI and also verified with histology. Severe damage to the inner ear barrier with Gd-DTPA-BMA leakage into the scala media was detected with MRI in 1 ES-damaged animal that had a 60-dB hearing loss. To conclude, endolymphatic hydrops can be visualized with high-resolution MRI by means of Gd-DTPA-BMA, and it is possible to quantify the extent of endolymphatic hydrops. Damage to the inner ear barrier or possible rupture of membranes can be shown with the assistance of Gd-DTPA-BMA.

The endolymphatic sac: a scanning and transmission electron microscopy study.

A recent investigation has suggested that the chief cells of the endolymphatic sac produce an endogenous inhibitor of sodium resorption in the kidneys, tentatively named saccin. In the current study, the ultrastructure of the endolymphatic sac and in particular the chief cells are described to demonstrate that this organ fulfils the morphological criteria of a potential endocrine gland. Accordingly, the chief cells are shown to exhibit all the organelles and characteristics of cells that simultaneously synthesize, secrete, absorb and digest proteins.