Biomedical subjects

L S Parnes

Publications and source records attributed to L S Parnes.

46 records · Page 3Linked to original sources

PubMed1990

Posterior semicircular canal occlusion for intractable benign paroxysmal positional vertigo.

Benign paroxysmal positional vertigo (BPPV) is most often a self-limited disorder arising from the posterior semicircular canal of the undermost ear in the Hallpike position. Some individuals with this disorder have severe and protracted symptoms requiring more than expectant therapy. We describe two patients with intractable BPPV and profound sensorineural hearing loss in the affected ear treated by transmastoid posterior semicircular canal occlusion. Postoperatively, both were relieved of their BPPV and demonstrated preserved lateral semicircular canal function as measured by electronystagmography. We feel this new procedure provides a simpler and possibly safer alternative to singular neurectomy and should be given future consideration in the treatment of intractable BPPV in a normal-hearing ear.

Adult↗

PubMed1990

Bilateral semicircular canal aplasia with near-normal cochlear development. Two case reports.

Congenital malformations of the vestibular labyrinth (pars superior) are rare. We present two patients with computed tomographic findings of bilateral semicircular canal aplasia with normal or near-normal cochleas. Initial bone conduction thresholds were within normal limits, although both patients had significant conductive hearing losses due to congenital middle ear malformations. Bithermal caloric responses were absent in both. To our knowledge these are the first reports of vestibular aplasia concomitant with normal or near-normal cochlear development. These findings conflict with conventional hypotheses that state that inner ear malformations result from arrested development during the normal stages of inner ear embryogenesis.

Adult↗

PubMed1990

Rotatory recovery nystagmus: an important localizing sign in endolymphatic hydrops.

Localizing the ear responsible for vertigo attacks may be exceedingly difficult in patients with delayed endolymphatic hydrops, vestibular Ménière's disease or bilateral Ménière's disease. This has important clinical implications when planning operative treatment. We present a case of delayed endolymphatic hydrops to exemplify these difficulties and demonstrate the localizing value of recovery nystagmus. We stress the importance when possible of monitoring patients with endolymphatic hydrops for recovery nystagmus during acute vertigo attacks. Monitoring should include direct eye observation as pure rotatory nystagmus escapes detection on electronystagmography.

Aged↗

PubMed1990

Vascular relationships of the vestibulocochlear nerve on magnetic resonance imaging.

Vascular compression of the vestibulocochlear (VIIIth) nerve may cause constant or recurrent positional vertigo, tinnitus, and/or hearing loss. At present the diagnosis is based upon history, physical findings, audiologic assessment, vestibular function testing, and auditory brainstem evoked responses. Delineation of the vascular and neural anatomy within the cerebellopontine angle (CPA) has not been part of the preoperative assessment. We recently treated a patient demonstrating the clinical features of this syndrome. A magnetic resonance imaging (MRI) study revealed a vascular loop of the anterior inferior cerebellar artery intimately associated with the VIIIth nerve at the porus acusticus. To better define the significance of this finding, we retrospectively reviewed the CPA neurovascular anatomy of 100 (200 sides) otherwise normal MRI scans performed for unrelated disorders. Vessels were identified on 59.9 percent of sides while nerves were seen on 40 percent of sides. Contact between vessel and nerve occurred on 12.5 percent of sides and when both nerve and vessels were seen concurrently, they were in contact 50 percent of the time. These findings may preclude the use of MRI as the definitive diagnostic test in the preoperative assessment of vascular VIIIth nerve compression.

Arteries↗

PubMed1989

Mycotic sinusitis: a management protocol.

There has been a recent increase in reported cases of fungal sinusitis. This may be due to better awareness and improved histopathological methods as well as increasing numbers of immunologically compromised patients. We present a case of mycotic sinusitis in an immunocompetent individual to emphasize the clinical features of this disease. The pathology and microbiology are analyzed and a management protocol is discussed.

Aged↗

PubMed1987

Percutaneous embolization for control of nasal blood circulation.

Percutaneous embolization to control the nasal blood circulation was used in 19 patients with vascular nasal disorders. Embolization was the initial treatment for intractable posterior epistaxis in 11 patients, 9 (82%) of whom were controlled without further treatment. Used as an adjunct to surgery on vascular nasal tumors, embolization reduced intraoperative blood loss in four patients to an average of 800 cc. In four patients with Osler-Weber-Rendu disease, treatment with embolization did not significantly alter the course of their disease. Overall, however, this relatively new technique enhances successful management of difficult epistaxis cases.

Embolization, Therapeutic↗

PubMed1987

Perilymph fistula: an important cause of deafness and dizziness in children.

This study underscores the importance of considering a perilymph fistula, an abnormal communication between the inner and middle ear, in any child with a progressive sensorineural hearing loss. A concomitant complaint of intermittent dizziness or observed spells of imbalance (56%) is another indication of the disease. Six of 16 patients (37.5%) with proven fistulas were less than 2 years of age at the onset of symptoms. Unless the fistula is identified and repaired by grafting, the ear may become totally deaf. This would be disastrous in the presence of bilateral fistulas, which occur commonly in children (56% of patients had symptoms of bilateral disease). Our experience in recognizing and treating fistulas and thereby saving and restoring hearing is described.

Adolescent↗

PubMed1985

Effect on brainstem auditory evoked responses of posterior semicircular canal occlusion in guinea pigs.

The site of origin of benign paroxysmal positional vertigo is the posterior semicircular canal and when persistent, the condition is known as cupulolithiasis. Singular neurectomy is the current procedure of choice for the treatment of incapacitating cupulolithiasis. The neurectomy is difficult to learn and carries a significant risk of hearing loss. An alternative procedure, whereby the posterior canal is occluded, is discussed. This was performed on 11 guinea pigs and the effect on hearing was measured using brainstem evoked audiometry. Eight animals showed no hearing loss while the other three had a mild to moderate loss of hearing due to intra-operative complications. The effect of canal plugging on hearing compares favorably with the hearing results obtained with singular neurectomy. Posterior semicircular canal occlusion is suggested as a safer and technically easier treatment for incapacitating cupulolithiasis.

Animals↗

PubMedDate not supplied

Pharmacokinetic profiles of ceftazidime in cochlear perilymph, cerebrospinal fluid and plasma: a high-performance liquid chromatographic study.

A pharmacokinetic profile of the antibiotic ceftazidime was established for perilymph, cerbrospinal fluid (CSF) and plasma in 12 guinea pigs using the technique of high-performance liquid chromatography. The mean peak levels of 13.35 mg/l in perilymph and 140.54 mg/l in plasma were reached within the first hour after a single intravenous dose of 100 mg/kg. The CSF mean peak level of 5.36 mg/l, however, was not attained until 3 h after injection. The half-life was about 4 h in perilymph, more than 6 h in CSF and less than 2 h in plasma. Six hours following administration, the perilymph drug concentration remained higher than the plasma level. The study indicates that ceftazidime has excellent penetration into perilymph. It is concluded that ceftazidime should be a very useful agent in the treatment of bacterial labyrinthitis caused by susceptible organisms.

Animals↗

PubMedDate not supplied

Middle cranial fossa acoustic neuroma excision: results and complications.

The middle cranial fossa surgical approach has been used for the removal of acoustic neuromas in 43 patients at the University of Iowa since 1974. Hearing was maintained in 50% of patients with tumors 1.5 cm or less outside the porus acusticus. Postoperative hearing, facial nerve function, and complications were similar to reports using the suboccipital or retrosigmoid approach to preserve hearing for this size tumor. The character of the tumor appears to dictate the postoperative outcome rather than the surgical approach.

Adult↗