Search PubMed⌕ Search

Biomedical subjects

E M Monsell

Publications and source records attributed to E M Monsell.

At least 37 records · Page 2Linked to original sources
PubMed1990

Diagnosis and treatment of arachnoid cysts of the posterior fossa.

Arachnoid cysts of the posterior fossa are rare. When arachnoid cysts are encountered, the presenting symptoms are frequently otologic, with hearing loss and imbalance occurring commonly. Three cases are presented with a previously unreported otologic symptom, that of bilateral hearing loss, which in one case was fluctuant. None of the patients had the common symptoms of unilateral hearing loss and headache. With the advent of computed tomography and magnetic resonance imaging, these cysts may be readily identified, usually with diagnostic imaging alone. Unfortunately there is often a delay in diagnosis because of the vague and fleeting nature of the symptoms. Because no single diagnostic symptom pattern is able to characterize all cases, it is believed computed tomography or magnetic resonance imaging or both are indicated in patients with long-standing otologic complaints--even in the absence of unilateral symptoms. Treatment of posterior fossa arachnoid cysts primarily consists of surgical procedures designed to decompress the cyst. In this series, treatment with diuretics alone resulted in improvement of symptoms during several years of followup, with no evidence of enlargement of the cysts.

Adult↗
PubMed1990

Sensorineural hearing loss and the diagnosis of acoustic neuroma.

Sensorineural hearing loss and tinnitus are gradually receiving more attention in medicine due to advances in diagnosis and treatment. Acoustic neuromas can now be detected when they are small, and early microsurgical removal results in the lowest overall morbidity. We examine the historical development of acoustic neuroma management, discuss current diagnosis and treatment, and present illustrative cases from our recent experience. Complaints of tinnitus and hearing loss, especially when unilateral, require appropriate medical evaluation.

Adolescent↗
PubMed1989

Age considerations in acoustic neuroma surgery: the horns of a dilemma.

Experience has shown that early removal of acoustic tumors results in less morbidity because the rate of surgical complications increases with tumor size. Nevertheless, acoustic tumors are benign and grow slowly--facts that support conservatism in elderly patients. We managed 21 patients with acoustic tumors over the age of 65. Eleven patients underwent immediate surgical excision. Ten patients were monitored clinically and with serial magnetic resonance imaging (MRI) or computed tomographic (CT) scans. To date, two of these patients have required surgical excision because of continued tumor growth. Our experience managing these patients both surgically and with "watchful waiting" is the subject of this report.

Adolescent↗
PubMed1988

Why do vestibular destructive procedures sometimes fail?

Vestibular nerve specimens and one temporal bone, from patients with vestibular symptoms after destructive surgery on the vestibular system, were studied by light microscopy. Surviving nerve axons in three specimens that followed retrolabyrinthine vestibular nerve section (RLVNS) were counted and compared to normative data. Results are consistent with persistence of the central processes of primary vestibular neurons in three specimens from patients who had persistent symptoms and ice-water caloric responses after RLVNS. Incomplete neurectomy probably results from anatomic variations in the plane of separation of the vestibular and cochlear portions of the eighth nerve in the posterior fossa. Regeneration neuromas were found in the vestibule after a complete transmastoid labyrinthectomy and a Fick sacculotomy; this indicates that wide degrees of injury to the labyrinth may provoke this response. Disabling unsteadiness after labyrinthectomy may or may not respond to revision surgery (translabyrinthine vestibular nerve section). The indications for revision surgery are discussed. The excision of Scarpa's ganglion by the translabyrinthine route offers the best chance to ensure complete removal of peripheral vestibular tissue, minimize postoperative unsteadiness, and prevent neuroma formation.

Adult↗
PubMed1988

Endolymphatic sac surgery in congenital malformations of the inner ear.

A retrospective analysis of 40 patients (49 ears) with congenital progressive sensorineural hearing loss who underwent endolymphatic sac surgery was performed. The inner ears were radiographically abnormal in 57% of operated ears. In the remaining cases, subtle malformations beyond the resolving power of radiographic studies were suspected. Early postsurgical hearing loss (defined as a loss greater than 10 dB in three-tone average or greater than 15% in speech discrimination score) was found in 29% of operated ears (14/49). However, only two of these patients lost all of their residual hearing postoperatively (2/49 or 4%). An enlarged endolymphatic sac was noted at surgery in 50% of those with significant postoperative hearing losses. Longer-term stability of hearing was assessed in 22 patients with bilateral inner-ear pathology who underwent surgery on one side only. A comparison of the hearing fate of the operated and nonoperated ears suggested no benefit from the surgical intervention when compared to the natural history of the disease. Based upon this experience, endolymphatic sac surgery for the purpose of hearing stabilization in patients with congenital malformations of the inner ear is no longer recommended.

Adolescent↗
PubMed1988

Surgical treatment of vertigo with retrolabyrinthine vestibular neurectomy.

Results for control of vertigo and preservation of hearing in patients who have had a retrolabyrinthine vestibular neurectomy (RVN) by our group were analyzed retrospectively. This procedure consists of selective section of the vestibular nerve in the posterior cranial fossa. Vertigo was completely controlled in all but two of 31 patients, one of whom required revision surgery to control attacks. Analysis of these two cases suggests that the cause of persistent vertigo is incomplete neurectomy. With our current surgical technique in patients with Meniere's disease, hearing results were not statistically different from our results with surgery of the endolymphatic sac. Control of vertigo was much more successful with the RVN than endolymphatic sac surgery.

Adult↗
PubMed1988

Endolymphatic sac surgery: methods of study and results.

Surgery of the endolymphatic sac (ELS) in classical Meniere's disease has fallen under attack and has been abandoned by some surgeons. We studied our results for vertigo and hearing in 83 patients undergoing surgery of the ELS for intractable classical Meniere's disease. Half of the patients were completely free of definitive attacks at 2 years; another quarter experienced substantial control. Three fourths noted an improvement in their level of disability. Results for vertigo were sustained at longer follow-up intervals. Nineteen percent had revision surgery (usually retrolabyrinthine vestibular neurectomy) for intractable vertigo within 2 years of the sac operation. The 1985 reporting method of the American Academy of Otolaryngology--Head and Neck Surgery was found superior to previous methods because it specified a meaningful follow-up interval, used a graded scale accounting for partial success in treatment, and separated results for vertigo and hearing. Nevertheless, optimal use of the method in the future will require prospective reporting and a concerted effort to avoid confusion between definitive attacks of true vertigo and adjunctive vestibular symptoms. Even though the mechanism of the beneficial effect of sac surgery is unknown, we have found it useful in the control of disabling vertigo.

Cost-Benefit Analysis↗
PubMed1987

Congenital malformations of the inner ear: histologic findings in five temporal bones.

The histopathologic findings in five temporal bones from three patients with congenital malformation of the inner ear are described. The external contour of the cochlea was deformed in two temporal bones, while the internal architecture was abnormal in all five temporal bones. Intracochlear abnormalities included defects in the interscalar septum, deficiencies in the modiolus, and a paucity of neural elements. Spiral ganglion cell populations varied, but were substantially diminished in all five temporal bones. Enlargement of the vestibule and semicircular canals (lateral and posterior) was seen in two temporal bones. A large vestibular aqueduct and saccular hydrops were found in one temporal bone each. An attempt was made to relate the histologic patterns of deformity to the proposed clinical classification of inner ear malformations. Radiographic abnormality of the cochlea would have been detectable in two bones (incomplete partition pattern), while two other bones would have appeared as vestibule-semicircular canal syndromes. One bone would have been radiographically normal.

Chromosomes, Human, Pair 13↗
PubMed1987

Brain herniation and space-occupying lesions eroding the tegmen tympani.

Technological advances in neuroradiology and the development of skull base surgery in neurotology have improved diagnosis and management of lesions eroding the tegmen tympani. The diagnosis of brain hernia is to be suspected in patients with a history of complicated chronic ear surgery and a slowly developing pulsatile mass with CSF leak. Patients are best evaluated in the upright position, with an otomicroscope and by magnetic resonance imaging (MRI). Over 6 years, our group has treated seven patients with eight space-occupying lesions eroding the tegmen. Five of the lesions were repaired with a temporalis muscle flap, 2 with fascia and bone, and 1 with Marlex. A review of new technology in the diagnosis of brain hernia and a modification of previous techniques is given.

Adolescent↗
PubMed1987

Surgical approaches to the human cochlear nuclear complex.

Patients with bilateral neural deafness may be candidates for rehabilitation with a device that provides direct electrical stimulation of the central nervous system. The cochlear nuclear complex at the pons-medulla junction is a logical site to implant because it is in the surgical field exposed for acoustic tumor surgery. In this study we compared four surgical approaches commonly used to reach the cerebellopontine angle for ease of access to the cochlear nuclear complex. We found the translabyrinthine approach to be the most satisfactory because the anterior approach facilitates identification of key landmarks, such as the tenia of the choroid plexus and the lateral recess of the fourth ventricle. The suboccipital, or retrosigmoid, approach would be satisfactory after removal of a large acoutic tumor; however, the amount of cerebellar retraction necessary may preclude its use in nontumor cases.

Cochlea↗
PubMed1986

Organization of the motor neuron components of the pallial nerve in octopus.

Following horseradish peroxidase (HRP) and cobalt (CO2+) application to the pallial nerve of two species of octopus, neurons that control various aspects of mantle behaviors were located in several lobes of the three main regions of the central brain. In the subesophageal region, cells were labeled in the anterior chromatophore, posterior chromatophore, palliovisceral, pedal and vasomotor lobes; in the superior buccal lobe of the supraesophageal region; and in the magnocellular lobe of the periesophageal region. Localization of labeled cells in and around both the anterior and posterior chromatophore lobes suggests a modification of the idea that a single functional area is solely located in an anatomically defined brain lobe of a cephalopod.

Animals↗
PubMed1985

Hearing and balance disorders. How to recognize, when to refer.

Nearly one in ten Americans has some degree of hearing loss. The primary care physician is frequently the first to examine patients with hearing and balance disorders. Examination begins with a thorough history and examination and may also include specific tests performed in the office. In many cases, the primary care physician can diagnose and treat disorders successfully. In other cases, referral to a specialist is necessary.

Aminoglycosides↗
PubMed1984

Functional hearing loss presenting as sudden hearing loss: a case report.

A case of functional hearing loss presenting as sudden sensorineural hearing loss in the only hearing ear of a musician is presented. Pure-tone audiometric evaluation showed good intratest and intertest consistency. The pitfalls of diagnosis, ultimately made by brain stem evoked response audiometry, are discussed in light of the literature on sudden and functional hearing loss. Psychiatric evaluation revealed features consistent with hysterical conversion. It is argued that it is important to establish the exact etiologic agent of functional hearing loss despite the difficulty of diagnosis so that the patient may receive appropriate treatment.

Adult↗
PubMed1983

Tumor involvement of the facial nerve.

Tumors involving the facial nerve are rare and challenging in both diagnosis and treatment. In this paper we report 18 cases of benign and malignant neoplasms involving the temporal portion of the facial nerve. The selection of those patients with facial paralysis who require detailed evaluation is discussed. Often, despite thorough evaluation of these patients, a preoperative diagnosis is unavailable or erroneous. An occasional patient may require surgical exposure of the nerve from the middle cranial fossa to the parotid gland.

Adult↗
PubMed1980

Cobalt and horseradish peroxidase tracer studies in the stellate ganglion of octopus.

The connectivity of the stellate ganglion of Octopus was investigated using cobalt and horseradish peroxidase (HRP) tracers applied to severed preganglionic and postganglionic nerves. Centripetal cells, defined as cells in the ganglion which send their axons back toward the brain, were discovered by both methods. Application of HRP to the pallial (preganglionic) nerve labeled the preganglionic fibers which enter the ganglion and spread widely within the neuropil. Application of either tracer to a single stellar (postganglionic) nerve labeled motor neuron cell bodies spread over 1/4 to 1/3 of the ganglion. Since there are 25-40 such stellar nerves per ganglion, it may be inferred that there is only a limited topographic relationship between the location of motor neuron cell bodies in the stellate ganglion and the segment of mantle muscle which they innervate. The axon and many side branches of these motor neurons were also labeled. The smooth, diffuse form of HRP labeling produced in pre- and portganglionic axotomized neurons in Oct0pus is similar in appearance to that produced in damaged mammalian neurons.

Animals↗
PubMed1980

Retrograde intraaxonal transport of horseradish peroxidase by neurons in octopus.

While retrograde axonal transport is the basis of a widely used neuroanatomical method, it has been rigorously demonstrated in vivo only in a few vertebrate species and not yet in an invertebrate. Evidence is presented that motor neurons of the octopus stellate ganglion are capable of retrograde intraaxonal transport of horeseradish peroxidase. This demonstration shows that retrograde transport occurs in widely divergent groups of animals, and may be a general property of neurons.

Animals↗
PubMedDate not supplied

Osteomyelitis of the clavicle.

Osteomyelitis of the clavicle is rare; however, it may occur following head and neck surgery. Risk factors include radiation, long-standing tracheitis, disruption of the periosteum or the cortical bone with interruption of the blood supply to the clavicle. Proper management includes early diagnosis, surgical debridement of soft tissue and bone, appropriate antimicrobial therapy, and coverage of the defect with a myocutaneous flap to protect the great vessels of the upper mediastinum.

Clavicle↗