[Otorhinolaryngological aspects of high altitude medicine]

The World Health Organisation estimates that about 40 million tourists every year climb to high (2,500-5,300 m) and extremely high altitudes (5,300-8,850 m). Thus altitude sickness and other health risks are increasing accordingly and so this fact requires clarification and advice for tourists in order to reduce the risks. That applies to the otolaryngologist, too. The non-traumatic health risks all result from the atmospheric conditions at high altitudes, in particular due to the lower atmospheric pressure. The partial pressure of oxygen (pO2), the temperature and the partial pressure of water vapour decrease continuously with increasing altitude and at the summit of the highest mountain on earth, Mt. Everest, the pO2 is reduced by two-thirds, from 212 to about 70 hPa. The temperature drops on average 6.5 degrees C per 1,000 m and at -20 degrees C 1 m3 of air contains at most just about 1 g of water vapour. The shortage of oxygen above 2500 m cannot be compensated for at once. Respiratory alcalosis, followed by hyperventilation, improves the alveolar loading of red blood cells (RBC) with oxygen, however, it also reduces the ventilatory drive from the central CO2-chemosensors as well from the peripheral O2-chemosensors located in the carotid bodies. Not until the alcalosis has been balanced by a renal secretion of bicarbonate, does the pO2-driven ventilatory stimulus normalize and the relative increase of RBC as a result of altitude diuresis improve and complete the acclimatisation. Up to an altitude of 4,000 m this adaptation takes several days to one week and up to 5,000 m up to 2 weeks. If acclimatisation has not taken place or has been insufficient, acute mountain sickness may develop. It is a harmless disorder, although it noticeably affects people physically and mentally and in some rare cases it might even develop into a life-threatening high-altitude edema in the brain or in the lung. Hematocrit values of up to 58 or even 60% at great altitudes are quite usual. Up to an altitude of 7,500 m the distortion product signals of the otoacustic emissions decrease not only between 1,000 and 1,500 Hz, but also between 3,000 and 4,000 Hz. The reduction of the inner ear signals, however, is reversible and disappears after descent. For the vestibular organ high altitudes do not mean a risk, either. 70% of all infections suffered by trekkers and climbers affect the upper airways. The cold, dry mountain air damages the mucociliary apparatus and thus leads a disposition towards acute recurrences in climbers suffering from chronic inflammations of the tonsils, the paranasal sinuses and the middle ear. In the oxygen-poor air these recurrences do not heal at all, or only very slowly, but also often tend to have a rather more complicated course.

[Audimont--a scientific research expedition to Mount Cho Oyu in the Himalayas]

Even though hearing and vestibular disorders at high altitude have been reported since 1938, their reasons are still unknown. During the Audimont Research Expedition the risk for cochlear and vestibular sensory cells has been quantified by otoacoustic emissions and videonystagmography. Vestibular disorders could not be observed up to 7050 meters. However, the outer hair cells in the inner ear showed a reduction of emissions at increasing height. The pattern of the inner ear reply, depending on the altitude, complies with an increase of the perilymphatic pressure. As the perilymphatic space corresponds directly to the subarachnoid space, the limitation of hearing thus appears to be a direct consequence of raised intracranial pressure.

Efficacy and safety of levocetirizine in seasonal allergic rhinitis

OBJECTIVE

Pharmacodynamic studies have demonstrated that levocetirizine is the active enantiomer of cetirizine. This first therapeutic trial of levocetirizine aimed at determining the dosage with the best benefit/risk ratio in patients with seasonal allergic rhinitis (SAR).

METHODS

Patients with seasonal allergic rhinitis were randomised in a placebo-controlled, double-blind, parallel-group multicentre study 2.5, 5, 10 mg levocetirizine or placebo once daily during 2 weeks. Patients filled in a diary evaluation card every evening before taking study medication using the classical (0-3) scale for assessment of severity of sneezing, rhinorrhea, nasal congestion, nasal pruritus and ocular pruritus over the preceding 24 hours. The Total Four-Symptom Score (T4SS) was calculated by adding the individual symptom scores, excluding nasal congestion.

RESULTS

470 patients were included and constituted the intent-to-treat population. All 3 doses of levocetirizine were significantly superior to placebo in reducing the mean T4SS over the 2 weeks (all P (0.001). Additionally, individual symptom severity scores for sneezing, rhinorrhea, itchy nose, and itchy eyes were also significantly decreased for all doses of levocetirizine. Levocetirizine was significantly superior to placebo in reducing symptom severity with an important global treatment effect (P = 0.0001), except for nasal congestion. Furthermore, there was simple linear relationship between levocetirizine dosages and reduction of T4SS (P = 0.001). All doses were well tolerated, somnolence was higher with 10 mg (10.2%) than 5 mg (1.7%) and other adverse events were more frequent with the highest dose.

CONCLUSION

Levocetirizine 5 mg once daily has an optimal benefit/risk ratio in the treatment of SAR.

[Cochlear and vestibular risk at high altitude]

Exposure to lowered oxygen pressure at high altitude results in various physiological reactions. The most important response besides hyperventilation is the elevation of the oxygen transport capacity, which simply is achieved by plasma diuresis. Hemoconcentration however not only increases oxygen uptake but also raises blood viscosity, serum osmolality and impairs blood flow. Various observations have suggested that hearing and postural properties deteriorate under these conditions at high altitude. Studies in hypobaric chambers and our own data indicate that the elevated hematocrit levels and hypoxemia may impair the central nervous system functions, resulting in altered speech discrimination, directional hearing, and postural control. However, there is no evidence that cochlear and vestibular sensory cells are affected, whether by acute hypoxia, nor by elevated hematocrit levels up to 58 %. Even an greater increase in serum osmolality or an impaired osmoregulation may not interfere with the outer hair cell function resulting in threshold shift and hearing loss.

[A patient with acoustic neuroma--The reason for the functional disorder of his inner ear?]

BACKGROUND

Acoustic neuroma is one of the classic causes of retrocochlear hearing disorders. Auditory brainstem response (ABR) testing with a sensitivity of about 90 % in the diagnosis of acoustic neuroma plays an important role as a screening method.

CASE REPORT

A patient suffering from an acute, unilateral sensorineural hearing loss with tinnitus recovered for a short period of time after being treated with low density lipoprotein (LDL-) apheresis improving hemorheology. Surprisingly, the reason for the sudden hearing loss was a tumor in the cerebellopontine angle with a maximum diameter of 2 cm, which was detected by magnetic resonance imaging (MRI). Auditory brainstem response testing (ABR), audiovestibular tests and other standard tests were negative concerning this diagnosis. There was no previous evidence for an acoustic neuroma in all investigations of cochlear disfunction except MRI.

CONCLUSIONS

The acoustic neuroma caused a compression of the labyrinthine artery in the inner auditory canal resulting in an acute unilateral hearing loss with tinnitus. Low Density Lipoprotein-apheresis was able to achieve a short term improvement of blood supply to the inner ear. Thus the compression of the labyrinthine artery caused by an acoustic neuroma could be compensated for the duration of about one week. Within this time the effect of LDL-apheresis decreased more and more. After a sudden unilateral hearing loss an acoustic neuroma must be ruled out even if the retrocochlear testing by ABR primarily shows no prolonged interpeak latency.

[Possible variations of free autogenous jejunum transplantation for differential reconstruction of the oropharynx]

INTRODUCTION

Resections of extensive tumours, recurrences and radiodermatitides at the neck cause complex defects. Free bowel transplantation enables one-stage reconstruction.

PATIENTS AND METHODS

In 35 out of 57 interdisciplinarily treated patients, small-bowel transplantation was performed for reconstruction. Thirty patients received cylinder grafts, five jejunal patch plastics. In four patients neoglottis formations according to Ehrenberger were performed. To cover soft tissue defects, two patients received scapular free flaps, eight patients a jejunal segment, incised at the anti-mesenteric side, the mucosa stripped and covered by a split skin graft.

RESULTS AND CONCLUSIONS

Thirty-four grafts were viable. One patient received a successful re-transplantation. One postoperative fistula at the hypo-pharyngojejunostomy was closed by a separated jejunal segment which was primarily used as monitor, two others by pectoral flaps. Separation of a jejunal graft into two or three segments enables restoration of swallowing, voice and covering soft tissue in a one-stage procedure. The whole reconstruction necessitates only one arterial and one venous microanastomosis at the neck.

[Coexistence of bilateral paraganglioma of the A. carotis, thymoma and thyroid adenoma: a chance finding?]

Bilateral carotid body tumors are quite rare neoplasms. The coexistence of bilateral carotid body tumor, thyroid gland adenoma and thymoma has not yet been reported in the literature. We report on a 59-year old male who presented with a bilateral cervical mass. After the standard diagnostic procedures and surgical removal the diagnosis of a carotid body tumor was confirmed. On physical examination, the carotid body tumor is usually palpable as a firm, painless cervical mass. Even though carotid body tumors are slow-growing, and from a histological point of view benign, they sometimes attain massive size and therefore compress the surrounding tissue and create clinical pressure symptoms. A hereditary-familial tendency of these tumors has been noted. A common neuroectodermal origin is proposed as an explanation for the coexistence of the carotid body tumor and multiple endocrine tumors.

[Differential diagnosis of parapharyngeal mass]

BACKGROUND

Parapharyngeal lesions are rare. Tumors arising in the parapharyngeal space can be silent clinically for a long period of time. Physical findings like dislocation of the pharyngeal walls or cervical swelling are often recognized by chance.

MATERIAL AND METHODS

Representing three cases of parapharyngeal tumors the differential diagnosis of parapharyngeal masses and the importance of the magnetic resonance imaging will be shown.

CONCLUSIONS

Mostly, parapharyngeal masses are represented by salivary gland tumors (40%-50%). The second most common tumors in the parapharyngeal space are neurogenic tumors (17%-25%). Paragangliomas are the third group of common parapharyngeal lesions (10%-15%). A mixed group of lesions like branchial cleft cysts, lymph nodes and hematogenic tumors represent the remaining part of the parapharyngeal masses (10%-33%). Most of the lesions (80%) are benign. Because of the magnetic response imaging a reliable preoperative diagnosis is possible in more than 80% of the tumors. The surgical management may also be influenced by the location of the tumor shown in the magnetic resonance imaging.

[All sudden hearing losses are not alike. Away from infusion therapy?]

The number of patients requiring treatment for acute functional disorders of the inner ear has increased over the last decades. The diagnosis sudden loss of hearing is made when the cause of a precipitous hearing impairment cannot be determined with clinical diagnostic means. In the large majority of such cases, the pathogenesis is unclear, with vascular, viral and autoimmune processes most commonly being considered. Against this background, numerous polypragmatic therapeutic measures are employed. In general treatment of sudden loss of hearing employs a combination of several drugs with perfusion-promoting or anti-inflammatory effects. However, the efficacy of such an approach has not been established. The present article discusses a number of known ideas on the pathogenesis of this condition, together with the associated therapeutic strategies, and reports on the importance of nitrogen oxide (NO), which as recent studies appear to show, plays an important role in the physiology of the cochlea.

Changes in serum osmolarity influence the function of outer hair cells

Fast motility of outer hair cells (OHC) is thought to be based on a hydromechanic principle. In vitro, the function of OHCs can be disturbed by a change in the osmolarity of the culture medium. Whether changes in the serum osmolarity in vivo can also interfere with OHC motility has not been investigated as yet. Serum osmolarity of New Zealand White rabbits (n = 18) was elevated by a continuous infusion of glucose 40%, decreased by an infusion of aqua dest, or kept constant by an infusion of saline. OHC function was monitored using distortion products of otoacoustic emissions (DPOAE). Input output curves were established between 2 and 5 kHz (geometric mean of f2) with primaries of levels between 35 and 55 dB SPL. Cochlear perfusion was measured using a fluorescence microsphere method. Elevation of the serum osmolarity from 306 +/- 17 mosm/l to 365 +/- 23 induced a decrease of DPOAE between 3 and 12 dB SPL. Cochlear blood flow increased from 0.11 +/- 0.09 to 0.15 +/- 0.10 ml/min/g. When decreasing the serum osmolarity from 303 +/- 9 to 281 +/- 8 mosm/l, only slight changes of the DPOAE could be verified. As in the control group, cochlear perfusion was almost unchanged. In the control group, neither serum osmolarity nor DPOAE changed. Comparable to findings in vitro, increasing the serum osmolarity can lead to a disturbance of OHC function. In patients suffering from sudden hearing loss. dehydration due to physical or mental stress is often observed. This new and promising pathophysiological concept needs further clinical evaluation.

[Exploratory analysis of risk factors of acute inner ear dysfunctions]

Aside from the clinical picture, the frequent occurrence of vascular risk factors favors a vascular pathogenesis of acute sensorineural hearing loss. However, the data on the association of vascular risk factors with sensorineural hearing loss are controversial. Achieving a sufficient number of patients and establishing a suitable control group is difficult. We analyzed the data of 393 patients suffering from acute sensorineural hearing loss. Risk factors, general, audiological, and laboratory parameters were investigated. Mean hearing loss and remission during 10 days of hospital treatment were calculated. The patient group was divided into patients with a certain risk factor and those without this risk factor, and mean remission and hearing loss were compared. Patients suffering from hyperlipidemia or hypotension had substantial and significantly higher mean hearing losses than patients not suffering from these diseases. Thrombosis, embolism, and hypertension were associated with a significantly worse remission of hearing loss. Repeated episodes of sensorineural hearing loss showed a significant worse remission, but less mean hearing loss before therapy. Smoking, diabetes mellitus, infections of the upper airways, and allergies had no influence on remission and mean hearing loss.

Hemoconcentration as a possible pathogenic factor of sudden hearing loss

Hemodilution is considered to be a useful therapy for sudden hearing loss by improving cochlear blood flow (COBF) as a result of decreasing viscosity of the whole blood. The purpose of this investigation was to evaluate whether hemoconcentration actually leads to a diminished COBF and impaired function of the cochlea to thus play a role in the pathogenesis of sudden hearing loss. Ten New Zealand White rabbits were anesthetized and ventilated. Cochlear function was evaluated by measuring distortion products of otoacoustic emissions (DPOAEs) at the beginning of each experiment and after 120 min. In the interim, each test animal's hematocrit was raised by an infusion of packed red cells. Control animals were not infused, so hematocrits were left unchanged. Reproducibility of DPOAE measurements were found to be dependent upon the stimulus level. Correlation coefficients were 0.83 for 65 dB SPL and 0.78 for 45 dB SPL. Although no changes in the absolute level of DPOAEs were observed after raising the hematocrit, correlation coefficients were diminished to 0.68 at 65 dB SPL and 0.58 at 45 dB SPL. Hemoconcentration caused no apparent changes in the cochlear function in our animals. Although these findings may reflect species differences, hemoconcentration might still be a factor causing sudden hearing loss in older, atherosclerotic patients.

[Hypercholesteremia and hyperfibrinogenemia in sudden deafness]

BACKGROUND

The pathogenesis of sudden hearing loss has not been elucidated as yet. Insufficient perfusion of the cochlea due to an increased blood viscosity, microthrombosis, or altered vasomotion are assumed. Hypercholesterolemia and hyperfibrinogenemia are frequently observed in patients with sudden sensorineural hearing loss. The aim of this study was to investigate the incidence of hypercholesterolemia and hyperfibrinogenemia in patients suffering from sudden hearing loss compared to normal controls. In an intervention study the impact of drastic lowering of plasma cholesterol and fibrinogen by a selective extracorporal apheresis was studied.

METHODS

In a case-control study of 23 patients suffering from sudden hearing loss, plasma cholesterol and fibrinogen levels as well as erythrocyte aggregation and plasma viscosity were determined. Seven sudden hearing loss patients from this group were treated with H.E.L.P. apheresis, an extracorporal procedure removing fibrinogen and idl-cholesterol from plasma.

RESULTS

Plasma fibrinogen and cholesterol levels were higher in sudden hearing loss patients, leading to significantly elevated values of erythrocyte aggregation and plasmaviscosity. Six out of the seven patients treated with a single H.E.L.P. apheresis immediately showed an improvement of auditory thresholds.

CONCLUSIONS

We conclude that hyperfibrinogenemia and hypercholesterolemia may contribute to the clinical event of sudden hearing loss. Our study shows for the first time that acute and drastic removal of plasma fibrinogen and low density lipoproteins can be an effective clinical tool in the treatment of patients with sudden hearing loss.

Cetirizine and pseudoephedrine retard, given alone or in combination, in patients with seasonal allergic rhinitis

We compared the efficacy and safety of cetirizine (5 mg), pseudoephedrine retard (120 mg), and the combination of cetirizine (5 mg) with pseudoephedrine retard (120 mg), each given twice daily for two weeks to subjects with pollen-associated allergic rhinitis. The study was multicentre and of randomized, double-blind, parallel-group design. Five rhinitis symptoms were rated according to severity on a scale of 0 - 3, daily by patients and at each clinic visit by investigators. A total of 687 patients, aged 9 - 66 years (mean: 32 years) was randomised to treatment (cetirizine: 231; pseudoephedrine: 226; combination: 230). On entry, the three groups were comparable in relevant respects. The primary outcome measure was based on the five symptoms assessed by the patients over the 2-week treatment period. The combination was more effective, providing at least 20% more "comfortable days" (symptoms absent or at most mild) than cetirizine or pseudoephedrine given alone (median values: 53.3%, 30.8%, and 33.3%, respectively; p < 0.001). For nasal obstruction, the combination (mean score: 1.19) was more effective than cetirizine (mean score: 1.43; p = 0.0005), but there was little difference between the combination and pseudoephedrine (mean score: 1.22; not significant). Sneezing, rhinorrhoea, nasal and ocular pruritus were better controlled by combination (mean 4-symptom score: 0.77) than by pseudoephedrine alone (mean 4-symptom score: 1.12; p < 0.001) and also better than by cetirizine alone (mean 4-symptom score: 0.93; p < 0.001). No unexpected adverse reactions were observed. A combination of cetirizine and pseudoephedrine retard is well tolerated and superior to each given alone for moderate to severe allergic seasonal rhinitis, especially when nasal obstruction is a predominant symptom.

[Piracetam infusions in acute tinnitus and sudden deafness]

In a prospective randomised clinical study on 39 patients with tinnitus and sudden hearing loss the therapeutic efficacy of piracetam/HAES 6% was compared with that of naftidrofuryl/HAES 6%. The two groups of patients were comparable in terms of demographic and audiological baseline data. The parameters evaluated were hearing improvement and the reduction in intensity of tinnitus. Improvement in hearing was 15 dB (piracetam) versus 18.5 dB (naftidrofuryl). The improvement in tinnitus amounted 27 dB (piracetam) and 19.9 dB (naftidrofuryl). Both differences were not significant. Tolerability was very good in both groups. Piracetam, which improves rheology and has a positive effect on metabolism, would appear of particular interest for the treatment of acute tinnitus.

[Middle ear ventilation with the Otovent latex membrane system]

Epidemiological studies have shown that up to 80% of all pre-school children develop Eustachian tube dysfunction with middle ear effusion and corresponding conductive hearing loss. The therapy of choice for hyperplastic adenoids is adenoidectomy, often in combination with paracentesis. The objective of this study was to determine whether regular middle ear aeration (Otovent-system) could obviate the need for paracentesis. To this end treatment of 146 children from four to ten years old was conducted within the guidelines of a study protocol. In one group of children, Otovent-supported middle ear aeration was carried out before and after adenoidectomy. In the control group, adenoidectomy was followed by paracentesis. Parents and children were then assigned to follow-up treatment. As additional supportive therapy, children in both groups received decongestant nose drops and a mucolytic agent for a period of 2 weeks. The success of the treatment was evaluated by tympanometry, tone-wave audiometry and ear microscopy. The patients were followed-up at intervals of two and four weeks after the initiation of treatment. The results show that within the study time frame, Otovent treatment compares well to paracentesis. In summary, regular Otovent-supported aeration of the middle ear in many cases can be an alternative to paracentesis.

[Hearing disorders after Bungee jumping?]

Acceleration forces in bungee jumping acting on the head are different in nature and extent from those in merry-go-round, looping and scooter rides. They act mainly in the vertical plane, horizontal accelerations may develop only during uncontrollable vibrations in different directions after slowing down. According to our present knowledge the risks for injuries of the cervical spine and functional disorders of the inner ear in bungee jumping are lower than in merry-go-round, looping and scooter rides. They seem to be enhanced, however, in individuals suffering from diseases of the cervical spine and disorders of the heart and the blood circulation.

[Microsurgical procedures in reconstructive otorhinolaryngologic surgery]

For reconstruction of bony and soft tissue defects numerous free flaps are available to the head and neck surgeon. Different tissues, as from skin, mucosa, fat, muscle or bone can be transferred by microvascular transplantation. Microvascular tissue transfer has completely replaced tissue transfer from distant donor sites and in daily routine now competes with pedicled tissue transfer. Most of the reconstructive problems can be solved by using a limited number of reliable and versatile flaps, e.g. forearm, scapular, latissimus dorsi and jejunal flap. The scapular flap offers advantages in reconstruction of extensive cervical soft tissue defects. In facial dysplasia, facial contours may be restored satisfactorily with a completely deepithelialised scapular flap. Facial soft tissue defects are closed most satisfactorily by cutaneous forearm flaps. Cutaneous scapular and forearm flaps also can be used as osteocutaneous flaps and are thus suitable for closure of additional mandibular and maxillary bony defects. The closure of large penetrating defects of the cheek is best achieved by the folded forearm flap. It also provides an ideal replacement of intraoral mucosa. For reconstruction of the tongue and the floor of the mouth the musculocutaneous latissimus dorsi flap generally shows the best functional results. In oro- and hypopharyngeal lining and replacement of the cervical oesophagus the jejunal transplant is superior to the forearm flaps.

[Incidence of Doppler ultrasound detectable stenoses of cervical arteries in patients with cochlear-vestibular symptoms]

Doppler ultrasound examination is an easy and non-invasive examination technique to image the anatomical and functional situation of cervical vessels. An increasing number of ENT-specialists has been using Doppler sonography in the diagnosis of cochlear and vestibular disorders. We analysed the frequency of pathological Doppler examination results of 150 patients with vertigo, hearing loss and tinnitus. Especially patients with vertigo bear a greater risk for stenosis of the extracranial arteries (28%) compared to an asymptomatical population (1%). Patients with hearing loss and tinnitus showed a different degree of artery disorders (23% of the patients with hearing loss; 18% of the patients with tinnitus). Patients bearing no risk for atherosclerosis showed in 13% (vertigo) and 8% (hearing loss and tinnitus) stenosis of the cervical arteries. Thus we found by Doppler ultrasound examination more stenoses in patients with cochlear or vestibular symptoms than in an asymptomatical population. The early attribution of stenosis to a malfunction of the inner ear helps to avoid invasive examinations of cervical vessels. In addition to this, imminent cerebral ischaemia can be revealed at an early stage.

[Does the otorhinolaryngologist need Doppler sonography?]

Doppler sonography has not only proved to be a non invasive but also a highly sensitive diagnostic tool for imaging of functional vascular disorders. The otorhinolaryngologist who in future will have to deal with an increasing number of neurootological problems, such as tinnitus, vertigo and hearing loss, should cover the Doppler sonographic examination of the vertebral and carotid artery and its branches. Ultrasound examination of these vessels should be performed in all patients suffering from cochlear or vestibular disorders and bearing risks for arteriostenosis. Early diagnosis does not only point out causative vascular changes but also helps to prevent the patients from invalidising or lethal cerebral events. The combination of (Doppler- and B-mode-sonography Duplex sonography) enables the ENT specialist not only to rule out functional vessel disorders but also to look for morphological vascular changes. Duplex scan imaging is far less risky than angiographic procedures and in many cases it is superior to these invasive techniques too.

[Infratemporal gout tophus--a rare differential diagnosis in primary parotid gland disease]

Soft-tissue tophi can be observed in up to 50% of patients with primary gout. They are firm deposits of monosodium urate in crystal form, which develop from pinhead-size to egg-size in the subcutaneous tissue. In the field of ear, nose, and throat diseases tophi have been described in such rare locations as the wing of the nose, the tongue, the epiglottis, and the arytenoid and thyroid cartilage. Tophus formation at the temporomandibular joint with extension into the fossa infratemporalis has been mentioned only three times in the world literature. -In the present paper, the authors report on the extraordinary location of an urate tophus in the fossa infratemporalis - in this case, there was even destruction of the middle base of the skull - which had been misinterpreted for years, having been diagnosed as a primary disease of the parotid gland.

[Modern radiologic diagnosis of the nasopharynx]

The nasopharynx is one of the most delicate areas of the head and neck for diagnosis and treatment. Biopsies can be taken easily under local anaesthesia; however, since many tumours in this particular region grow in the submucosa, biopsies taken from the superficial tissue layers might not show any signs of malignancy. Thus, diagnostic imaging has become important in evaluating the nasopharyngeal region. Until the early seventies, when computed tomography (CT) was introduced, conventional tomography was commonly used. Since the development of CT and --particularly--the "high-resolution" technique, tumour infiltration of the skull base and parapharyngeal space as well as intracranial extension can be evaluated sufficiently and the different compartments of the soft tissue can be clearly distinguished due to their varying density. Magnetic resonance imaging (MRI)--a new technique introduced a few years ago--yields a much better soft tissue contrast than CT. Contrast enhancement after application of Gd-DTPA provides further information on tumour outlines and architecture. Benign lesions can be distinguished from malignant tumours, as well as recurrent tumours from postoperative fibrosis. MRI can also show large bony defects while minor infiltrations of the skull base are detected by HR-CT. Both MRI and CT are well-established methods in diagnosing diseases of the nasopharynx and its surroundings. For evaluations of the vascular supply prior to operation digital subtraction angiography (DSA) might be necessary in some cases.

[Hormone receptors in the inner ear]

Vasopressin binding sites could be clearly demonstrated in the cochlea. Membrane staining was mainly limited to the apical and ciliar membranes of the cochlear and vestibular hair cells, and hence to membranes in which adenylate cyclase activity could not be demonstrated. In addition to V2-vasopressin receptors that mediate hormonal signals by adenylate cyclase activation and cAMP release, in V1-vasopressin-receptors extracellular vasopressin signal is mediated by the breakdown of inositol phosphates and the release of inositol-triphosphates and diacylglycerol. Inositol triphosphates were found to be responsible for the intracellular mobilization of calcium. The localization of vasopressin binding sites at the hair cell membranes, therefore, suggests that vasopressin contributes to the breakdown and release of phospholipid messenger molecules and is thus probably involved in cochlear and vestibular signal transduction.

[Free microvascular tissue transfer. Clinical significance in reconstructive surgery of the head and neck]

Free microvascular anastomosed tissue transfer has improved the reconstruction of soft tissue defects dramatically. For reconstruction of facial and cervical soft tissue defects numerous free flaps are available to the head and neck surgeon, however, most of the reconstructive problems can be solved by using a limited number of reliable and versatile techniques. In microvascular tissue transfer, the scapular flap offers similar advantages as to reliability and versatility as the pectoralis major flap in pedicled tissue transfer. In contrast to the scapular flap the groin flap is more bulky, its skin is soft and may carry pubic hair on its medial aspect. After partial maxillectomy or in facial dysplasia facial contour may be restored satisfactory with a completely or partially de-epithelialized scapular flap. In total hypopharyngeal and cervicoesophageal defects the jejunum transplant provides an ideal tubular replacement. If after resection of an intraoral carcinoma with partial mandibulectomy an osteocutaneous transfer has to be achieved the mandibular defect may be reconstructed with bone from the iliac crest or from the radius while the intra- and extraoral tissue defect may be closed with the adjacent skin flaps. For the closure of large penetrating defects of the cheek the inferior epigastric abdominal wall flap in particular has proved a versatile and reliable flap. This flap offers both, a cutaneous and a peritoneal surface. Latter is used for the replacement of the intraoral lining.

[Diseases of the lymphatic system of the head and neck region. A comparative study of MRI and CT]

The diagnostic possibilities of magnetic resonance imaging compared with computed tomography in lymphomas and pathological enlargement of the lymph nodes in the head and neck region are presented. Whereas plain MRI examinations showed the same diagnostic sensitivity as CT, application of the paramagnetic contrast medium Gd-DTPA in 50 of 87 patients clearly increased diagnostic accuracy. Signal intensities of T1- or T2-weighted images before therapy (operation, chemotherapy, radiotherapy) and after administration of Gd-DTPA were enhanced, compared with posttherapeutic and plain examinations. An increase after therapy in two patients signalled a relapse or residual tumour tissue; a decrease in three cases was evaluated as response to therapy. Other differential diagnostic processes such as lipomas, neurinomas, glomus tumours etc. were differentiated with the help of signal intensity curves after administration of contrast media and the use of a gradient echo sequence TR/TE = 30/12 msec with a flip angle of 30 degrees. Differentiation of tissue based on morphological criteria such as homogeneity of tumour tissue or the delineation against surrounding tissue structures showed in the case of Hodgkin's disease and inflammatory diseases mainly homogeneous elements without ring-shaped structure. Non-Hodgkin lymphomas had a predominantly homogeneous structure. In squamous cell carcinomas MR revealed in two cases a ring-shaped enhancement.

[Magnetic resonance tomography in tumors of the salivary glands--a diagnostic advantage?]

40 patients with clinically palpable salivary gland masses were included in a prospective study to compare magnetic resonance imaging to computed tomography. MRI has proved superior to CT not only in imaging primary lesions but also in diagnosing local and regional recurrences. In evaluating border structures, signal intensity, T1- and T2-values of space occupying lesions, we can determine the tumour status. Besides, we can define to some extent the internal architecture of the salivary gland or intra-resp. periglandular lymph node masses. Better contrast resolution and more specificity can be obtained by the use of contrast medium gadolinium-DTPA. Even small intraglandular and periglandular masses can be clearly distinguished from the sourrounding structures. At present, magnetic resonance imaging offers the diagnostic potency of both sonography and computed tomography. The advantages of MRI and our present indications in imaging salivary gland masses are discussed.

MR imaging of the oropharynx and tongue: comparison of plain and Gd-DTPA studies

The effect of intravenously administered gadolinium-diethylene-triamine pentaacetic acid (Gd-DTPA) on signal intensity in comparison to plain noncontrast imaging was analyzed. Sixty-one patients with diseases of the oropharynx and tongue base were examined using multiplanar magnetic resonance (MR) imaging. The contrast medium Gd-DTPA was administered in 26 cases. Thirty-eight patients also underwent CT. Forty-one patients had surgery and pathological verification. Plain MR imaging was equal or superior to CT in all except one patient. Marked contrast enhancement produced by Gd-DTPA was observed in carcinomas, sarcomas, inflamed salivary glands, and in normal pharyngeal mucosa. The usefulness of Gd-DTPA may be increased by measuring the enhancement in signal intensity versus time to allow a better differentiation of histological features.