1/12. Biophysical basis for inner ear decompression sickness.Isolated inner ear decompression sickness (DCS) is recognized in deep diving involving breathing of helium-oxygen mixtures, particularly when breathing gas is switched to a nitrogen-rich mixture during decompression. The biophysical basis for this selective vulnerability of the inner ear to DCS has not been established. A compartmental model of inert gas kinetics in the human inner ear was constructed from anatomical and physiological parameters described in the literature and used to simulate inert gas tensions in the inner ear during deep dives and breathing-gas substitutions that have been reported to cause inner ear DCS. The model predicts considerable supersaturation, and therefore possible bubble formation, during the initial phase of a conventional decompression. Counterdiffusion of helium and nitrogen from the perilymph may produce supersaturation in the membranous labyrinth and endolymph after switching to a nitrogen-rich breathing mixture even without decompression. Conventional decompression algorithms may result in inadequate decompression for the inner ear for deep dives. Breathing-gas switches should be scheduled deep or shallow to avoid the period of maximum supersaturation resulting from decompression.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
2/12. Horizontal canal type BPPV: bilaterally affected case treated with canal plugging and Lempert's maneuver.A 54-year-old woman complained of positional vertigo. During 3 months' observation, the patient showed mostly geotropic or apogeotropic nystagmus due to right canalolithiasis or cupulolithiasis, however, she sometimes showed nystagmus which suggested left horizontal canalolithiasis. We suspected that she suffered from bilateral horizontal canal type benign paroxysmal positional vertigo (BPPV) and performed Lempert's maneuver for both directions, however, they were ineffective. She underwent canal plugging for right horizontal canal. After surgery she showed no positional nystagmus of right horizontal canal origin. However, apogeotropic nystagmus of the left horizontal canal origin was still observed. This nystagmus changed to geotropic nystagmus and finally disappeared following Lempert's maneuver for the left side. Bilateral horizontal canal BPPV is difficult to be resolved, probably because physical treatment for one side would move debris to the cupula in the other canal. Canal plugging combined with Lempert's maneuver to the other side is one treatment option for intractable bilateral horizontal canal BPPV.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
3/12. Delayed labyrinthine fistula in canal wall down mastoidectomy.PURPOSE OF THE STUDY: This article is a retrospective review of 5 cases of delayed labyrinthine fistula in patients with a longstanding canal wall down mastoidectomy. MATERIAL: All patients had a long-term postoperative follow up with no evidence of complications till they suddenly started to have vertigo. The symptoms were caused by a bony erosion of the lateral semicircular canal detected on physical examination or by a CT-scan. There was no evidence of a recurrent cholesteatoma. RESULTS: The patients underwent surgery in order to close the fistula, with a good result. In all cases, a factor such as an infection or trauma, seems to have triggered off the bone erosion. CONCLUSION: Late complications may occur in the canal wall down mastoidectomy technique, after a long period of follow up in the absence of recurrent cholesteatoma. For this reason, it is advisable to look for a labyrinthine fistula in patient who develop vertigo a long time following mastoid surgery with a resultant radical cavity.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
4/12. The perilymph fistula syndrome defined in mild head trauma.Neurological and neuro-otological studies were carried out on 102 adults with mild cranio-cervical trauma productive of positional vertigo and perilymph fistula as confirmed by laboratory tests, and by the finding of perilymph fistula at tympanotomy in the surgically managed group. In this patient group, all other neurological and neuro-otological diagnoses were excluded, e.g. epilepsy, cerebral palsy, multiple sclerosis, retardation; and for the neuro-otological group those with a history of ototoxicity, labyrinthitis, Meniere's disease, chronic ear infections, or developmental or familial disorders. Emphasis in this study was on mild trauma: fewer than half of the sample had been rendered unconscious in the injury of record, and a third of the cases were of whiplash type, with no loss of consciousness (LOC) and no remembered headstrike. These concomitant lesions comprise the perilymph fistula syndrome (PLFS) with a unique profile of neurological, perceptual, and cognitive deficits resembling a post-concussion injury. A complete description of the clinical picture is given, including psychological, cognitive and diagnostic tests, and the outcome of bedrest vs. surgical management. PLFS can arise from minor trauma, fistula are frequently bilateral (71/102), a mild sensorineural hearing loss is of variable occurrence (53%), secondary hydrops is not uncommon, and women appear more vulnerable than men for developing the syndrome. As based upon combined laboratory techniques and clinical symptomology, fistula were correctly predicted in 61 of 65 laser-operated ears. The positional vertigo component of PLFS was in all cases managed according to a special physical therapy program utilizing exercises for vestibular symptom habituation. Even when diagnosed late, a good-to-excellent outcome was achieved in 70% of treated patients.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
5/12. Otologic and otoneurologic injuries in divers: clinical studies on nine commercial and two sport divers.In the past two decades, we have seen a great increase in the number of injuries from commercial and sport diving. During this time, our knowledge of the physiology and pathophysiology of diving has also increased. As a result, we now can accurately diagnose and successfully treat many of these injuries. Of the commercial and sport divers examined as pateints in the Department of otolaryngology at the University of texas Medical Branch in Galveston, Tex., between September, 1974, and May, 1975, 11 showed positive otologic and otoneurologic findings which are reported herein. One patient was surgically explored for an oval window fistula. In localizing and classifying these injuries, we have utilized extensive and broad-based test batteries, which include complete history, otologic and otoneurologic physical examination, audiometry, a central auditory test battery, and a vestibular test battery. These tests are described. The findings in each of the divers are illustrated and analyzed. This article further describes the use of these test batteries, which were employed to localize otoneurologic pathology in this sample of injured divers. Based on these cases, we have expanded and modified Edmonds' classification of the etiology of vertigo related to diving. We feel that the test batteries which we describe, or similar tests, should be part of the otologic and otoneurologic workup of injuries divers.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
6/12. Intractable vertigo--when not to operate.patients with episodic vertigo--or one severe episode of vertigo--may respond to vestibulosuppressive medications or operations on the labyrinth. In patients with constant incapacitating vertigo or disequilibrium, the clinician should suspect nonlabyrinthine disease. A careful history and physical and neurologic examinations will provide clues to underlying disease and direct the selection of further objective tests.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
7/12. Perilymphatic fistula: a histopathologic study.Over the last two decades, clinical criteria for perilymphatic fistulae have been defined to the extent that differentiation can be made between such fistulae and other balance-affecting disorders such as Meniere's syndrome. On the assumption that the specimens in the temporal bone bank of the University of chicago Medical School that had been obtained from patients having vertigo, hearing loss, or both, before those clinical criteria were so defined might have been classified incorrectly, we proposed a retrospective histopathologic study, with prediction of two independent variables: a clinical history and physical findings consistent with the diagnosis of perilymphatic fistula and communication between the vestibule and the middle ear adjacent to or via the fissula ante fenestram. Eleven pairs of temporal bones with the histologic diagnosis of idiopathic labyrinthine hydrops were evaluated before the clinical histories relevant to those specimens were reviewed. In one specimen, a communication between the vestibule and the middle ear space was identified. In none of the other specimens was there a similar communication. As this study continued, significance was given to the histologic details of the communication between the middle ear and posterior canal ampulla. The temporal bones without these communications did not have clinical histories consistent with the diagnosis of perilymphatic fistula.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
8/12. ataxia and hearing loss secondary to perilymphatic fistula.ataxia is rarely attributed to lesions of the peripheral vestibular system. In 1973, the first case of ataxia and hearing loss secondary to a labyrinthine fistula was reported. Until now, this syndrome has not been reported in patients under the age of 10 years. A case is presented of a 5-year-old boy with symptoms of ataxia and hearing loss as well as vertigo and tinnitus after head trauma. Three physical findings appear to be most characteristic of patients with perilymphatic fistulas: a positive fistula response, positive positional testing with the involved ear down, and evidence of vestibular ataxia when testing station and gait. The absolute diagnosis of perilymphatic fistula can only be established by exploration of the middle ear space. If a fistula is found, it may be sealed with soft tissue and, if this fails, actual stapedectomy may be required.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
9/12. Acoustic tumors: atypical features and recent diagnostic tests.About one-third of patients with acoustic tumor (AT) initially seek medical attention for nonaudiologic complaints. The nonspecific early symptoms of AT require the inclusion of AT in many neurologic differential diagnoses. Advances in electrophysiologic and radiographic tests have allowed earlier diagnosis of AT at a time when abnormal physical findings other than hearing loss are present in less than half of patients. The availability of brainstem auditory evoked response testing, fourth-generation CT, and air-CT cisternography have changed the approach to the diagnosis of AT. Neurologists should be cognizant of recent diagnostic advances.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
10/12. Sudden or fluctuating hearing loss and vertigo in children due to perilymph fistula.Five cases are presented of children with rapid onset of sensorineural hearing loss, disequilibrium, or both, who were found at exploratory tympanotomy to have a perilymph fistula. Four of the children had histories suggesting that antecedent barotrauma or physical exertion contributed to the development of the fistula. One child with congenital unilateral craniosynostosis had a residual temporal bone abnormality on the same side as the perilymph fistula. Two children had identifiable anatomic abnormalities in the middle ear. A classification of perilymph fistula is proposed that describes a congenital, an acquired, and a combined type of fistula. Inner ear fluid dynamics and patency of the cochlear aqueduct appear to be important factors in pathogenesis. Children with unexplained fluctuating or sudden onset of sensorineural hearing loss, and children with unexplained disequilibrium or vertigo should be suspected of having a perilymph fistula. The history can be singularly important in raising the suspicion that a perilymph fistula may be present. Although audiometric, vestibular, and radiographic studies can be helpful, there is no way to prove the presence or absence of a fistula without directly viewing the middle ear. Tympanotomy with repair of the fistula does not assure improvement in hearing.- - - - - - - - - - ranking = 0.2keywords = physical (Clic here for more details about this article) |
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