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El mecanismo exacto de la neumatizacion del sistema de celulas mastoideas y los factores que influencian este proceso es pobremente comprendido. Factores geneticos, como tambien adquiridos, han sido implicados en el proceso de neumatizacion del sistema de celulas mastoideas. Esta neumatizacion es considerada un factor de importante pronostico en la conduccion de las cirugias reconstructivas de oido. Hemos llevado a cabo un estudio para explicar el rol de dos importantes factores adquiridos en la duracion de las otitis media cronica y el status funcional de la tuba auditiva en la neumatizacion de las celulas mastoideas. En 50 individuos, con otitis media cronica unilateral, se estudio su sistema de celulas aeriferas mastoideas usando la planimetria y las funciones de la tuba auditiva usando fluorescina, via nasofaringoscopia. Los resultados concuerdan con estudios previos, indicando una influencia definida de enfermedades cronicas del oido medio en el proceso de neumatizacion, aunque la duracion de la enfermedad no fue significativa. En contraste con los estudios previos, no se encontro influencia del status funcional de la tuba auditiva en la neumatizacion mastoidea

Objectives: The purpose of this study was to determine the prevalence and characteristics of patients with pneumatized articular eminence (PAT) in a group of Turkish children in order to make a contribution to pneumatization phenomenon in childhood. Methods: 1049 panoramic radiographs were retrospectively evaluated. PAT was defined as nonexpansile, non-destructive cyst-like radiolucency in the zygomatic process of the temporal bone, which appears similar to the mastoid air cells. It was classified as unilocular or multilocular on the radiograph. Statistical comparison of gender, age and localization was performed using a chi-square test (P , 0.05). Results: Twenty-four pneumatized articular eminences were found in 17 patients, representing a prevalence of 1.62%. Patients with pneumatized articular eminence had a mean age of 11.2 (SD 3.13) years with a range of 7‐16 years. Eight cases (47.1%) occurred in girls and nine cases (52.9%) occurred in boys. The results of statistical tests showed no statistically significant differences among the groups with respect to gender, age and localization (P , 0.05). Conclusions: Pneumatization of accessory air cells begins before puberty, contrary to the general opinion and statements. Knowledge about these structures is helpful for the interpretation of imaging such as panoramic radiographs and provides valuable information to understand the spread and differential diagnosis of pathological entities in this region. Dentomaxillofacial Radiology (2006) 35, 365‐370. doi: 10.1259/dmfr/77401728

BACKGROUND : The paranasal sinuses and mastoid air cells vary considerably in size and shape from person to person. The main structures are pneumatic. In this study, we investigated the relationship between right and left sides and evaluated the volume changes according to age and sex. METHODS : Of all patients attending the radiology department, 91 cases without paranasal sinuses and mastoid air cells pathology (i.e., inflammation, operation or trauma) were selected for evaluation. Axial computed tomography (CT) scans were obtained for both paranasal sinuses and temporal bones. In all scans, the volumes of each area (maxillary sinus, frontal sinus, sphenoid sinus and mastoid air cell) were calculated and analyzed statistically. RESULTS : The volumes of paranasal sinuses and mastoid air cells increased with age and women had a lower mean volume. There was a positive correlation between right-left and ipsilateral structures (paranasal sinuses and mastoid air cells). CONCLUSIONS : These results are helpful in understanding the normal and pathological conditions of the paranasal sinuses and the mastoid air cells.

Objectives: To regenerate of the mastoid air cells and their functions for the treatment of incurable otitis media. Materials and Method: In situ tissue-engineered mastoid air cells using three-dimensional hydroxy apatite (3D-HA) of honeycomb-like structure were used as artificial pneumatic bones. This 3D-HA is made of calcium phosphate and has a high ratio of micropores, 90%. Its surface is coated with collagen. Ten patients (4 males, 6 females) for this clinical study were randomly selected among the patients with severe cholesteatoma, adhesive otitis media, and purulent chronic otitis media, and they were to be received a staged operation. At the first stage of tympanoplasty, collagen-coated 3D-HA was put into the newly opened mastoid cavity, and it was fixed by fibrin glue. Recovery of mastoid aeration and regeneration of the pneumatic air cells of the mastoid cavity were estimated by images of high-resolution computed tomography (HRCT) after the first operation. At the second stage of operation, histopathologic examinations of specimens of HA taken from the reopened mastoid cavity were performed. Results: Aerations in the mastoid cavity were observed in 9 of the 10 patients within 12 months after the second operation. Moreover, the pneumatic structure in the mastoid cavity was partially regenerated in five patients. In these successful cases, mucosa with newly formed capillaries was observed on the surface of the implanted HA at the second stage of operation. In the failure cases, however, connective tissues and granulations invaded the space of the 3D-HA. They were observed as soft-tissue density areas in the HRCT scan images. Conclusions: This study indicates that mucosa can grow on the surface of implanted artificial 3D-HA and can have a gas exchange function in the newly opened mastoid cavity. These tissue-engineered mastoid air cells may be a possible treatment for intractable otitis media.

AIM To investigate the contribution of routine review of submillimetric multiplanar reformats to the diagnosis of skull-base fractures. METHODS A prospective analysis was performed of 407 cases referred over a 6-month period for CT of the skull following cranial trauma. The reformatted 5-mm axial sections and subsequently the high-resolution multiplanar reformats (HRMPRs) were viewed on an ADW 4.1 workstation using bone windows and algorithm. All skull-base fractures and related features, recorded by the consensus of two radiologists, were classified as anatomically significant or non-significant on the basis of eight criteria. The clinical features of skull-base injury and any subsequent treatment were noted in all cases of skull-base fracture. RESULTS HRMPRs detected 80 separate skull-base fractures in 36/407 cases. Of these 80 fractures, 57 were visible on 5-mm axial sections. In 8 of the 36 cases, the significant anatomical features were only evident on review of the HRMPRs. In 6 of the 36 cases, none of the skull-base fractures was visible on 5-mm sections, but these individuals had only minor associated clinical features and no therapeutic requirements. Review of HRMPRs could have been confined to patients with skull-base fractures, abnormal intracranial and extracranial air collections or opacified mastoid air cells revealed by 5-mm axial sections. This policy would have led to the detection of 79/80 (99%) of skull-base fractures and all significant anatomical features. CONCLUSION The 5-mm axial sections demonstrated 71% of skull-base fractures and 78% of skull-base fractures with significant anatomical features, using HRMPRs as a gold standard. There were no significant clinical sequelae at short-term follow-up of those fractures only evident on HRMPRs.

The tympanic membrane (TM) and mastoid air cells are measurable pressure buffers of the middle ear (ME).Pressure homeostasis of the ME is maintained approximately atmospheric by mechanisms that neutralize (buffer) pressure fluctuations, two of which are the TM and mastoid.Negative pressures were induced by volume changes in an artificial ME model. Those were recorded directly while using a rigid or a flexible TM with "mastoids" of various sizes.In the rigid TM model, the volume changes correlated linearly with the induced pressures and were confirmed to fit Boyle's law. In the flexible TM model, the pressure/volume correlation was nonlinear up to -50 mmH2O, where the TM was maximally displaced (approximately 25 mm3), became rigid, and constituted 75%, 41%, and 33% of the buffering gained in tandem with the "mastoid" in a model having a "mastoid" of 0, 5, and 10 mL, respectively. Altogether, a large "mastoid" required a greater volume change than a small one to induce the same pressure.The mastoid air volume "dilutes" pressure changes relatively to its size: the volume change required to alter a given pressure in an average (6 mL) mastoid is six-fold that which is needed in a small (1 mL) mastoid. ME volume reduction by TM retraction buffer negative ME pressures. This maximal ME volume change is constant for a "normal" TM. Therefore, it is the ME with the small mastoid that is most vulnerable to pressure changes and may develop compensatory buffering mechanisms, e.g., additional TM retraction (atelectasis) and/or ME volume reduction by fluid accumulation.

Contention exists on the development of pneumatization of temporal bone. Many techniques to measure the volume of pneumatization have been reported, but no techniques for direct surface area measurement. We measured the surface area and volume of human mastoid air cells. Eight normal temporal bones removed at autopsy were analyzed and fixed in formalin fixative, decalcified, and embedded in celloidin, sectioned at 25 microns and stained with H-E for histological examination. Total surface area and the volume of human mastoid air cells were measured using a personal computer. The surface area of pneumatic spaces for the 8 temporal bone specimens ranged from 36.1 cm2 to 163.0 cm2 (mean +/- SD: 89.1 +/- 34.0 cm2). The volume of pneumatic spaces for the 8 specimens ranged from 1.53 ml to 6.03 ml (mean +/- SD: 4.12 +/- 0.97 ml). The surface area of temporal bone pneumatic spaces we determined could serve as useful basic data for determining the physiology of ventilation for the temporal bone and the function of mastoid cells.

Supraarticular, supramastoid and suprameatal crests on the outer surface of the squamous part of the temporal bone are of clinical importance as they are accepted as landmarks for some surgical approaches relating to the temporomandibular joint, the middle cranial fossa and mastoid air cells, respectively. Because of the surgical importance of the crests, their incidence and the relations between them were studied on a total of 442 (250 male, 192 female) dry skulls. In addition, three-dimensional (313) surface renderings of the squamous part of the temporal bone were created from routine axial computed tomographic (CT) images in four cadaver specimens to demonstrate the surface anatomy. Suprameatal crests were observed commonly as a trace type on the male dry skulls (51.2%), though no such crest was seen on most of the female skulls (54.4%). Supramastoid crests were commonly observed as a small crest on male dry skulls (46.6%), but as a trace type on female dry skulls (52.05%). Supraarticular crests were commonly seen as a trace type on both male (58.6%) and female (70.6%) dry skulls. In the light of the above data, it can be concluded that the crests on the male dry skulls were stronger than those on the female skulls. The angles between the crests were also examined. It was observed that the angle between the supraarticular and supramastoid crests was larger in male dry skulls compared with the female dry skulls. On the other hand, no gender difference was observed when the angle between the suprameatal and supraarticular crests was examined.

Perfimttion of the tympanic membrane is nature’s may of maintaining the middle far vntilation under the pressure of inflammatory process in the tempanomastoid cleft. An attempt at reconstruction with the possibility of infection lurking in and around the mastoid air cells may seem futile. Vow the quntinn arises as to whether a cortical Mastoidectomy is essential before an attempt at reconstruction is made. Our experience with one hundred and twenty patients is presented here. Our study shovn that conicul mastoidectomy does not signifieantly improve the results in well-selected ears.

Combined use of an operating microscope and a middle ear endoscope seems to be helpful for selecting an appropriate surgical technique and for identifying more patients in whom cholesteatoma can be removed by a trans-canal approach alone. To investigate whether attic cholesteatoma can be treated by a trans-canal approach alone, a review was performed of patients who had undergone endoscopically assisted tympanoplasty and the outcome of surgery was compared with the preoperative CT findings. Using a rigid endoscope (3 mm in diameter and 6 cm in length with a viewing angle of 30°), twenty eight patients were examined to determine whether total resection of the cholesteatoma was possible by trans-canal atticotomy alone. According to the CT findings, total resection of cholesteatoma was possible by trans-canal atticotomy combined with the use of a rigid endoscope not only in 4 patients with the shadow localized in the epitympanum on preoperative CT scans but also in 18 out of 24 patients with the shadow extending from the epitympanum to the distal mastoid air cells. This study indicates that the trans-canal approach with endoscopic guidance is a useful technique for the treatment of cholesteatoma.

The total surface areas of human mastoid air cells were measured using digital CT scans. Using 24 normal ears, the lining of the mastoid air cells was digitally scanned, traced and analysed. The mean surface area of the mastoid air cell system was 167.0.cm2 and ranged from 74.78 to 330.01 cm2. The volume was also measured, the mean being 10.43.cm3 ranging from 6.25 to 20.52.cm3. The correlation coefficient between surface area and volume was 0.95. These results indicate that well pneumatized mastoid air cells serve to provide an extremely large surface area in the temporal bone which in normal mastoid air cells is proportional to the volume.

The aim of this study was to determine the prevalence of incidental findings in MRI of the temporomandibular joint (TMJ).MRI reports of 730 patients were assessed. The reports were analysed by one consultant and one clinical lecturer in dental and maxillofacial radiology. The prevalence of intracranial and extracranial incidental findings was recorded and categorized.There were 53 (7.3%) incidental findings, of which 11 (1.5%) were intracranial and 42 (5.7%) were extracranial (divided into paranasal sinuses, mastoid air cells, muscle hypertrophy, lymphadenopathy and salivary glands). A total number of eight intracranial findings needed further dedicated imaging and/or specialist clinical opinion. Only one tumour (a meningioma) was found and required surgical intervention.Incidental findings on TMJ MRI are rare but not unheard of. The clinical relevance of incidental findings can be significant, and it is therefore important to ensure that the full data set of images is inspected, including any scout slices. A close working relationship between the areas of dental and maxillofacial radiology and neuroradiology is essential in expediting a second opinion relating to intracranial findings. All incidental findings should be communicated to referring clinicians in a timely manner, based on their urgency and clinical significance.

To examine whether gas exchange occurs in the middle ear air cell system independent of the eustachian tube (ET), we occluded the middle ear clefts of piglets, whose tympanic bullae closely resemble the human mastoid air cell system, and investigated subsequent changes in the air cell system. We anticipated that pneumatization and development of the air cell system would continue if gas were exchanged through the mucosa lining the air cell system. If, on the other hand, mastoid air cells depend on the ET, mastoid development would be impaired or arrested. In noninflamed ears, pneumatization was maintained, and development of the air cell system continued after the middle ear cleft had been occluded with an acrylate adhesive and the bullar air cell system was thus excluded from any communication with the ET. These results indicate that the normal middle ear air cell system has the capacity to perform gas exchange independently of the ET, with gas exchange appearing to occur through the submucosal capillary network.

The effect of mastoidectomy on mastoid pneumatization was investigated in an animal model. Experimental mastoidectomy was performed on the air cell system of the tympanic bullae in 10 four-week-old piglets. The developmental process of this structure is very similar to that of the human mastoid air cell system. Two piglets each were decapitated at 1 and 2 weeks, and 1, 3 and 5 months after the operation, and hematoxylin and eosin sections of the bullae were examined histopathologically. The development of the tympanic bulla itself was not affected by the operation. However, inside the bulla, a great amount of bone tissue had proliferated peripheral to the surgical cavity without new formation of normal pneumatized cells. When mastoidectomy was performed in the course of the pneumatization, subsequent pneumatization did not occur in this animal model. This result suggests that mastoidectomy in childhood may arrest the new formation of mastoid air cells in humans.

Intracranial epidural abscess is an uncommon but potentially life-threatening condition requiring prompt recognition and management. Most commonly it arises secondary to infection in the paranasal sinuses, mastoid air cells or the middle ear. It has also been described following craniotomy and trauma. This report describes three cases reported to our institution over a 15 month period, two associated with frontal sinusitis and one with no obvious predisposing factor.

A series of 221 ears with chronic suppurative otitis media without cholesteatoma is presented--84% of the cases were treated using one-stage tympanomastoidectomy and 15% underwent cortical mastoidectomy with planned second-stage tympanoplasty. Mean follow-up period was 6.3 years. Control of infection succeeded in 92% after the primary operation. Failures were most common in ears infected with Pseudomonas aeruginosa. Postoperative cholesteatoma developed in 5 ears (2.2%). Hearing results were unsatisfactory; a postoperative air-bone gap within 20 dB was achieved in only 62%. In revision operations, retained mastoid air cells were found in 64% of ears with recurrent or persistent discharge. Thirty-seven percent of patients with unsuccessful outcome were observed to have a possible underlying or concomitant disease. The importance of intensive preoperative conservative treatment and careful surgical technique is stressed.

The ventilation mechanism of the middle ear is very important as regards the pathogenesis of middle ear disease, but its mode of function is still obscure. Therefore, we tried to measure the ventilation and clearance of the middle ear using radio-isotope imaging techniques and 133Xe in order to gain a clearer picture of the ventilation mechanism. In normal Eustachian tube cases, approximately 10% of the initially insufflated gas immediately entered into the middle ear cavity and mastoid air cells. The gas introduced into the middle ear diminished at a rate of 8% of volume per hour in the normal resting state. Two hours after the first procedure, air was insufflated, and gas volume in the middle ear cavity immediately diminished by 30%. In stenotic tube cases, it proved difficult to insufflate the gas into the middle ear, however, its diminishing rate with the passage of time was slightly faster than in normal tube cases. From this data, it was evident that air could easily and quickly enter into even the periphery of the mastoid air cells by insufflation via the Eustachian tube, despite the fact that the middle ear and mastoid air cells form a closed cavity. In the resting state, moreover, the air in the middle ear was thought to be absorbed mainly into the middle ear mucosa at a regular rate. It was confirmed that the insufflation procedure as a therapy for tubal stenosis and OME is very useful for the ventilation of the middle ear.

Pulsatile tinnitus is an uncommon condition. We describe a case of pulsatile tinnitus and visually demonstrate a pulsating tympanic membrane caused by a postoperative cerebrospinal leak into the mastoid air cells following resection of a left temporal petrous meningioma. To our knowledge, this is the first case in the literature where an objective pulsatile tinnitus has been captured on video (see www.laryngoscope.com).

Background Idiopathic inflammatory medial meatal fibrotizing otitis (IMFO) is rare. Only a few cases with unknown cause have been reported. Objective To report 3 cases of IMFO as a specific diagnostic entity. Patients and Methods Two adults and 1 child with bilateral IMFO were observed for several years at the Department of Otorhinolaryngology of Helsinki University Hospital, Helsinki, Finland. Results Only the osseous part of the external ear canals was affected by IMFO. The skin and skin organs over the lateral cartilage of the ear canals remained rigorously and constantly uninflamed through the active, relentless progression of the disease over several years, resulting in the formation of a fibrous plug of the medial meatal canal. The middle ears and mastoid air cells were not affected during the active inflammatory phase. Conclusion IMFO has its own specific pathophysiologic characteristics, and perhaps also etiopathologic characteristics, which are still unknown.

A case is described where a cranium from an unknown individual is identified by comparison of antemortem and postmortem computerized tomographic (CT) images of the bony structure of the skull. While on at least one occasion CT scans of individual cranial landmarks have been used to identify unknown remains, this study is remarkable because positive identification of a deceased individual was accomplished by performing a CT scan on an unidentified cranium and comparing multiple landmarks and images with corresponding features in an antemortem CT scan of a missing man. Bony details of the frontal and sphenoid sinuses, ethmoid and mastoid air cells, sagittal cranial suture, and the torcula (the internal occipital protuberance) were exactly the same on both CT scans, confirming them as the same person.

The mortality pattern of women who began employment as luminizers in the radium dial industry before 1930 was followed through 1990. Hazard models with time-dependent covariates were used on mortality data either organized by individual death times or grouped into cross-classified person-year tables. These models were used to quantify trends in mortality associated with either death from or diagnosis of bone sarcoma or head carcinoma. The accumulation of skeletal doses from 226Ra and 225Ra was an important predictor of the risk of death from bone sarcoma. Women exposed to 226Ra at ages associated with active bone growth were at greater risk of bone sarcoma than women receiving even larger exposures at an age when their skeletons would have been fully developed. Exposure to only 226Ra was found to be an important predictor of risk for carcinoma of the mastoid air cells and paranasal sinuses. For the cranial sites, where adult dimensions are attained early in life, an effect of age at exposure could not be detected.

A case of mixed type adenoma of the middle ear and mastoid is presented in which CT showed complete opacification of the middle ear and mastoid air cells with bulging of the tympanic membrane but without ossicular or bony destruction.

The ventilation and clearance of the middle ear were measured by radioisotope imaging techniques in order to gain a clear picture of the mechanism of ventilation. Radioactive xenon gas was insufhated into the middle ear of 9 normal subjects via the Eustachian tube, and observed by scinti camera. The volume was calculated with the passage of time. Approximately 11% of the insufflated gas immediately entered into the middle ear cavity and mastoid air cells in spite of the fact that the middle ear and mastoid air cells are a closed cavity. The gas in the middle ear diminished at a rate of 6% of volume per hour and it was thought to be absorbed mainly into the middle ear mucosa at a regular rate in the resting state.

A case of benign intracranial hypertension occurring in an 11-year-old boy, and due to lateral sinus obstruction, is reported. Computerized tomographic scan was conclusive, revealing a normal ventricular system and no evidence of a neoplastic lesion. Disappearance of the mastoid air cells and disruption of the trabecular pattern were also shown on the affected side. The diagnosis was confirmed at operation, and the course was favourable. In accordance with other studies cited, our findings suggest that patients suspected of benign intracranial hypertension can be spared invasive neuroradiological procedures if the computerized tomographic scan of the head is normal.

The function of the Eustachian tube under atmospheric pressure, on the grounds of our studies, is discussed as follows: (1) Criteria of natural valvular function of the auditory tube under a normal pressure environment. (2) Opening action of the Eustachian tube and mode of swallowing movement in comparison with soft palate movement. (3) High pressure environment and (opening action of) Eustachian tube. (4) Children undergoing tubing and their Eustachian tube function. (5) Ventilatory function of the Eustachian tube under normal pressure conditions. (6) Factors influencing changes in pressure in the tympanic cavity.

In 69 ears with chronic otitis media and nine ears with traumatic perforations tubal function, the size of the mastoid air cell system measured planimetrically on roentgenograms and the functional volume of the air filled ear spaces were studied for any correlations. The roentgenographic area and the functional volume were also studied for any variation in the duration of the disease. A correlation was found between abnormally small volumes and impaired tubal function, probably due to mucosal damage of the whole system, i.e. Eustachian tube, middle ear and mastoid air cells. No such association was found between area and tubal function. The volume, but not the area, decrease with the duration of the disease.

In order to clarify the factors influencing the prognosis of otitis media with effusion in children, we correlated the duration of middle ear effusions with five items: sex, age, laterality, the area of the mastoid air cells and the hearing level of air conduction. We examined 317 ears of 250 children with otitis media with effusion. Each ear was decided to have improved or not improved on the basis of tympanometric findings. No significant difference was found between the two sexes. Younger children showed less improvement than older ones, and those with bilateral involvement had poorer results than those with unilateral otitis media. No correlation was found between the area of mastoid air cells and the duration of effusion. Ears with severe hearing impairment were less apt to recover. It was concluded that age, laterality and the hearing level at the first visit can be used as prognostic factors in this disease.

In a material of healthy ears and ears with chronic otitis media the distribution of the air cell system has been measured with a direct volumetrical method and a planimetrical-roentgenological method. A high correlation between the two methods of measurement has been established.

A report of a case of atypical mastoiditis with Bezold’s abscess has been given. X-ray examination of the mastoid has been found to be very helpful. After exenteration of the diseased mastoid air cells and clearing the middle ear of the granulations a tympanomyoplasty has been performed which imparted significant improvement in hearing.

Teleological reasoning would conclude the existence of a destined function of the mastoid air cells. The function is alleged to be well established in man. The demonstration of its existence is attempted in different ways. Hypothetically, functions of varying nature may be ascribed to the mastoid air-cell system. A weight-reducing effect in birds is obvious. An insulating effect against differing climatic conditions may plausibly be considered. This may be of importance for all elements of the inner ear or for only one of them. Furthermore, the addition of the air cube to the middle-ear spaces may serve for an adjustment of air-pressure variations caused by the exchange of air through the open or partially closed tubal canal and by resorption. This may be of importance for the movement of the drum membrane and the hearing. Judging from the otological literature, a sound-silencing effect has been ascribed to the mastoid air

FLUID WHICH has accumulated in the mastoid and middle ear cleft, behind an intact tympanic membrane, theoretically, might find an escape from the confines of these spaces by two possible routes: down a patent eustachian tube, or by absorption into the submucosal plexus of lymph and blood vessels. The method whereby the eustachian tube may serve as a channel for the egress of fluids which have accumulated in the middle ear cleft has been studied. 2 It was noted that in order for the tube to act as an escape route, the pressure within the mastoid and middle ear spaces must be at least equal to the pressure in the nasopharynx. If, however, the pressure within the mastoid air cells and tympanum is lower than the pressure in the nasopharynx, then any fluid which is partially filling these spaces may remain for an undetermined period of time. Some authors feel

✓ A case of a large intracranial pneumatocele arising from mastoid air cells is reported. The patient became symptomatic after multiple coughing spells and required craniotomy for repair of the dural hiatus. The possible etiology of such a large spontaneous pneumatocele is discussed in the context of a review of the pertinent literature.

The middle ear is part of a functional system composed of the nasopharynx and the eustachian tube (anteriorly) and the mastoid air cells (posteriorly). The only active muscle that opens the eustachian tube is the tensor veli palatini, which promotes ventilation of the middle ear. The eustachian tube also functions to protect the middle ear from excessive sound pressure, and nasopharyngeal secretions. The eustachian tube helps drain the middle ear during opening and closing by pumping secretions from the middle ear; clearance of secretions also occurs. An understanding of the anatomy and physiology of the system can aid the clinician in understanding the role of eustachian tube dysfunction in the cause and pathogenesis of middle ear disease and the possible contribution of allergy to this disease.

Late biological effects of radium deposited in the human skeleton have manifested themselves unequivocally as osteogenic sarcomas or carcinomas of the mastoid air cells or paranasal sinuses. On the basis of current estimated risk factors, it might be expected that an excess of certain other malignancies could occur in a population of the size of the group exposed to radium (some 3500 cases located, which more than 2000 have measured 226Ra and 228Ra burdens), compared with the incidence in the population at large. An increased incidence of breast cancer has already been reported in female dial workers and it was related to the initial radium intake. On the other hand, very little information is available on the induction of leukaemia by alpha-radiation in human bone marrow. This paper therefore reports an investigation of the incidence of leukaemia among the radium workers. This covers a very wide range of radium burdens and has been done in the light of reasonable estimates of the mean alpha-particle dose received by the skeletal haemopoietic marrow. The number of leukaemia cases is identified and compared with (a) the expected number in a comparable population of the same size and age distribution and (b) predictions based on the risk factor proposed for protection purposes by the ICRP and on the estimated bone marrow doses.

It has been demonstrated that in most ears with middle ear effusion the mastoid air cells may be involved as well. The mucosal changes and the secretion extends into all cavities of the ear including the mastoid air cells. In most ears insertion of a ventilating tube through the tympanic membrane is adequate for proper aeration of the middle ear as well as of the mastoid air cell system. The draining usually stops and the mucosa gradually changes into its normal condition. In a small percentage of these, the ear will continue to drain and the mastoid will not clear up. Antibiotics and decongestants fail to cure the ear. Surgical intervention of the mastoid may be indicated in the rare cases where conventional treatment fails to control the condition. The aim of this report is to 1) focus attention to the fact that the mastoid is an integral part of the middle ear cavity; 2) discuss the pathogenesis in stubborn ears with middle ear effusion; and 3) demonstrate the surgical procedure commonly used in our department in order to reestablish aeration of the mastoid air cell system. Early recognition and proper treatment of ears with middle ear effusion will hopefully reduce the incidence of stubborn cases and also decrease the number of those cases which end up with chronic otitis media and cholesteatoma. It is hoped that the screening programs involving school and even preschool children, as well as new preventative programs, will diminish the frequency of cases which need extensive surgery as discussed in this paper.

A child aged 3 1/2 died from a cardiac condition after many and prolonged antibiotic courses: bilateral glue ear had been treated for the previous 18 months. Histopathology showed cholesterol granulomata in the mastoid air cells, with evidence of old hemorrhage, and of former inflammation of bone. The exudate was histiocytic with some giant cells. An 'orange spot' on the tympanic membrane was hyperaemic middle-ear mucosa, heavily infiltrated by plasma cells, lymphocytes and histiocytes. There was no evidence of hypersecretion. Some of the most abnormal areas were around the stapedial niche and the round window.

We investigated the development of mastoid air cells in cases of otitis media with effusion (OME) contracted during the fastgrowth period of childhood. It was considered that, if a comparative study of these cases against subjects in normal health was conducted on what types of effects of chronic inflammation of the middle ear in a child has on the development of the mastoid air cells from the time of onset until adulthood, it might reveal a major clue to the causal relationship between chronic inflammatory conditions of the middle ear and inhibited pneumatization of the temporal bone.

Carcinoma of the middle ear is rare, arising in association with chronic suppuration. It may begin in the altered epithelium of the middle ear, in the mastoid air cells, or deep in the external auditory meatus and, with a ruptured tympanic membrane, finds no difficulty in spreading to the middle ear (1). Cases of carcinoma of the external auditory canal which are limited to the canal are not included in this discussion. For a time the disease is confined by the bone which it later invades and has a tendency to spread into the middle cranial fossa. By more superficial extension, it perforates the cartilaginous canal and spreads on the exterior surface of the skull. The patient presents with an exacerbation of his discharge which may be blood-stained, or with continuous deep boring pain from bone invasion, or with facial paralysis. The lymph nodes in the neck become involved, and finally, if the patient survives, uncured, distant metastases to the liver and lung become apparent. The diagnostic problem is on...

OBJECTIVE To investigate the utility of lower contrast medium doses for the detection and conspicuity of acoustic schwannomas. MATERIALS AND METHODS The L/B (L, lesion; B, background) ratios or lesion contrast of 17 pathologically proven acoustic schwannomas studied with a standard dose (0.1 mmol/kg) of gadopentetate dimeglumine was measured. In addition, 22 patients with acoustic schwannomas were studied prospectively with fractional doses using the incremental dose technique. Each patient received an initial bolus injection of one-eight the standard dose (0.0125 mmol/kg) followed by an injection of one-eighth, one-fourth, and one-half the standard dose at 5 min intervals to achieve a cumulative dose of one-fourth, one-half and full dose, respectively. Imaging was performed immediately after each injection. RESULTS Standard dose--The L/B ratios of pathologically proven acoustic schwannomas to mastoid air cells ranged from 14.8 to 41.2 (mean +/- SEM, 28.0 +/- 1.95), which were approximately 17 times more than those of intraparenchymal lesions. Fractional cumulative dose--Qualitative visual analysis demonstrated that all acoustic schwannomas showed apparent enhancement at one-fourth dose. Intense enhancement was noted at one-half and full dose. Quantitative analysis demonstrated the mean L/B ratios between the acoustic schwannomas and mastoid air cells of the precontrast and one-eighth, one-fourth, one-half, and full dose studies were 8.33 +/- 0.52, 11.21 +/- 0.75, 13.02 +/- 0.83, 15.38 +/- 0.98, and 18.03 +/- 1.36, respectively. CONCLUSION The L/B ratios or lesion contrast of acoustic schwannomas at various fractional contrast medium doses was significantly higher compared with that of intraparenchymal lesions. Thus, the standard contrast medium dose may not be necessary for detection of acoustic schwannomas, and a fractional dose may be sufficient. Although the optimal fractional dose remains to be determined, one-half of the standard dose (0.05 mmol/kg) appears to be sufficient because of intense enhancement at this dose.

The authors report a case of a gas-filled epidural cyst communicating with the mastoid air cells, causing fluctuating but progressive amaurosis. No prior report of a similar finding could be found in the literature.

Among 1474 women employed in the United States radium dial-painting industry before 1930, there are 61 known cases of bone sarcoma and 21 cases of carcinoma of the paranasal sinuses or the mastoid air cells (''head carcinomas''). The relative effectiveness of /sup 226/Ra and /sup 228/Ra and dose-incidence relationships were examined for the 759 of these women whose radium body burden has been determined; there are 38 cases of bone sarcoma and 17 cases of head carcinoma in this group. Incidence (I) was expressed as tumor cases per person-year and the dose parameter (D) was the quantity (microcuries) of radium that entered the blood during the period of exposure. To the observed data for each type of tumor were fitted equations that can be formulated from the general form I = (C + alpha dD+ ..beta..D/sup 2/)e-..gamma../sup D/, where C, the natural incidence for this population, was about 10-/sup 5/ per person-year. For each equation, the best values of the dose coefficients were found by a least-squares fitting procedure. An equation of the form I = (C + BD/sup 2/)e-/sup ..gamma..D/ provided the best fit for the bone sarcomas, when the dose was expressed as microcuries of /sup 226/Ra plusmore » 2.5 times microcuries of /sup 228/Ra. An acceptable fit to the head carcinoma data was provided by the linear equation I = C + d alpha ..gamma.. with D equal to microcuries of /sup 226/Ra. As a test of bias due to selection of cases with known symptoms of malignancy, the analyses were repeated after removal of all cases for whom radium was determined only after exhumation, and no significant changes in the fitted coefficients were found. The dose-incidence equations obtained when the dose was expressed as average skeletal dose in rad are also given.« less

A case of pseudoepitheliomatous hyperplasia involving the external, middle ear, and mastoid air cells and labyrinth resulting from long standing irrigations with alcohol is described for the first time.

In the course of routine autopsies we have observed occasional cases of subdural suppuration (figs. 1 and 2) which is apparently secondary to an underlying leptomeningitis. We wish to eliminate from this discussion all cases of subdural infection secondary to causes other than underlying disease of the leptomeninges. Specifically, we exclude subdural suppuration secondary to extension from diseased paranasal sinuses, mastoid air cells and the middle ear. Similarly, we exclude from consideration subdural infection arising from a penetrating cranial injury, infected subdural hematoma and osteomyelitis of the skull. REVIEW OF LITERATURE A diligent search of the literature failed to reveal any papers on this subject except for a single article by Bateman, in 1929. 1 In this report there is a passing reference to subdural suppuration secondary to involvement of the pacchionian granulations in cases of purulent leptomeningitis. PRESENTATION OF CASES In a series of 95 consecutive cases of leptomeningitis