PubMed Health⌕ Search

Biomedical subjects

M E Glasscock

Publications and source records attributed to M E Glasscock.

At least 19 recordsLinked to original sources
PubMed1996

Mutational spectrum in the neurofibromatosis type 2 gene in sporadic and familial schwannomas.

Using a heteroduplex approach and direct sequencing, we have completed the screening of approximately 88% of the neurofibromatosis type 2 (NF2)-coding sequence of DNA extracted from 33 schwannomas from NF2 patients and from 29 patients with sporadic schwannomas. The extensive screening has resulted in the identification of 33 unique mutations. Similarly to other human genes, we have shown that the CpG sites are more highly mutable in the NF2 gene. The frequency, distribution, and types of mutations were shown to differ between the sporadic and familial tumors. The majority of the mutations resulted in protein truncation and were consistent with more severe phenotype, however three missense mutations were identified during this study and were all associated with milder manifestations of the disease.

Codon↗
PubMed1996

Stapedectomy in profound cochlear loss.

Stapedectomy can be used in certain patients with profound sensorineural hearing loss and stapes fixation to improve hearing to a level at which a hearing aid may be effective. This study reviews the outcomes of 11 patients with profound cochlear loss secondary to otosclerosis who underwent stapes surgery performed by the senior author (M.E.G.) over a 25-year period. Postoperative hearing aid usage was effective in 9 of 11 patients. Preoperatively, these patients derived no benefits from hearing aids. Stapedectomy may be of immense value in patients with the proper history and profound cochlear loss.

Aged↗
PubMed1996

A surgical solution for the difficult chronic ear.

We all encounter them: difficult chronic ears that seem to confound management efforts and that constitute an unrelenting imposition to the patient. Typically these ears have undergone multiple surgeries and are chronically infected. Such cases are commonly associated with residual or recurrent cholesteatoma. Those rare ears that temporarily respond to therapy promptly recur once treatment is withdrawn. Even the most aggressive nonsurgical protocols fail these patients, who exhibit lifelong social and professional incapacity. They seem to ultimately defy resolution. The purpose of this article is to present a surgical solution to the difficult chronic ear dilemma that emphasizes disease control. Treatment outcome is reviewed in 541 cases. Management pitfalls are analyzed with follow-up, in some cases 20 years.

Adolescent↗
PubMed1996

Endolymphatic system shunting: a long-term profile of the Denver Inner Ear Shunt.

Endolymphatic system surgery for Meniere's disease, particularly endolymphatic shunting, remains controversial. In 1988, we presented our findings on the efficacy of the Denver Inner Ear Shunt in 100 patients. These data were accumulated in the short term. The purpose of this article is to review the long-term results of our endolymphatic shunt procedure, highlighting the population of Denver Inner Ear Shunt recipients. Results were analyzed according to both 1972 and 1985 AAO-HNS criteria. We seek corroboration or refutation of our preliminary conclusion that (a) endolymphatic shunt surgery has little efficacy and that (b) the Denver valve does not appear to offer any advantage in this regard.

Adolescent↗
PubMed1995

Twenty-five years of experience with stapedectomy.

The purpose of this report is to review the outcomes of patients undergoing stapes surgery by the senior author during the past 25 years, and to compare these results with those obtained in other series. A retrospective analysis of 902 patients who underwent stapes surgery by the senior author from 1970 to 1994 was performed. Twenty-two patients underwent stapedotomy; the remainder underwent stapedectomy. Pure-tone averages for air and bone conduction, air-bone gap closure, technique, complications, and patient satisfaction were compared with results obtained in other stapedectomy and stapedotomy series.

Adolescent↗
PubMed1995

Ossiculoplasty using the black hydroxylapatite hybrid ossicular replacement prostheses.

The problems of ossicular reconstruction in chronic ear surgery have led to the development of new ossicular replacement prostheses. Improvements in biocompatibility and design led to the development of hydroxylapatite hybrid (HaH) ossicular replacement prostheses. The senior author's (M.E.G.) experience with the Black HaH prostheses is reviewed. Sixty cases are grouped by procedure and prosthesis (19 TORPs and 41 PORPs) with a minimum follow-up of 1 year. Audiometric data are analyzed to determine the success rate in air-bone gap closure. Complication and extrusion rates are reviewed. These results are compared against those obtained using other prostheses using similar criteria, and this report serves as a follow-up on a previous paper on this subject by the senior author.

Adult↗
PubMed1994

The natural history of untreated acoustic neuromas.

The emergence of magnetic resonance imaging with gadolinium has dramatically enhanced our ability to accurately detect the presence of acoustic tumors as small as 2 mm in diameter. Early diagnosis and improved surgical techniques continue to reduce the morbidity associated with surgical removal of these lesions. There exists, however, a select group of patients in whom no treatment may be the most appropriate management. Since 1979, a total of 51 patients with radiographic evidence of an acoustic neuroma have been prospectively followed for tumor growth and progression of symptoms. Patients were chosen for this conservative approach on the basis of age, medical condition, tumor size, audiometric data, and patient preference. This study reveals that a significant number of patients with acoustic tumors can be safely followed with regular imaging studies and may never require treatment. Discussed are tumor growth rates, epidemiology, and the impact of these factors on patient management.

Adult↗
PubMed1994

Facial nerve neuromas presenting as acoustic tumors.

Facial nerve tumors can present as masses in the internal auditory canal or cerebellopontine angle and may mimic an acoustic neuroma. These tumors can occur in any segment of the nerve from the brain stem to the neuromuscular junction. Prior to the advent of computed tomography and magnetic resonance imaging with gadolinium, facial nerve tumors were often difficult to diagnose. Even with these modalities it may be difficult to distinguish preoperatively between an acoustic neuroma and a facial schwannoma. Particular signs and symptoms associated with facial nerve tumors (in the spasms, and a facial tic. These symptoms, combined with modem radiologic studies, should allow for more accurate diagnosis, patient counseling, and treatment. This report presents a series of 32 facial nerve tumors diagnosed and treated at The Otology Group from 1975 to 1992. Of these lesions, 12 (38%) were thought to be acoustic neuromas. Eighteen tumors were correctly identified preoperatively as facial nerve tumors. Two facial nerve tumors were found incidentally.

Adult↗
PubMed1993

Bilateral aberrant internal carotid artery case presentation.

Cases of aberrant internal carotid artery in the middle ear have been well documented. However, bilateral aberrant intratympanic carotid artery presentation, as in this case, is quite rare. In addition, in this case, there was unilateral duplication of the cervical and petrous portions of one internal carotid artery such that the duplicated portion rejoined the normal internal carotid artery in its petrous portion. The purpose of this article is to review the literature regarding aberrant internal carotid artery presentation in the middle ear and to discuss the related embryological and anatomical features as well as diagnosis of this lesion, using a unique case as an example.

Carotid Artery Diseases↗
PubMed1993

Management of carotid artery hemorrhage in middle ear surgery.

Iatrogenic injury to the carotid artery as it traverses the middle ear in its normal anatomic position is a rare but potentially life-threatening event. Predisposing factors include a thin or dehiscent plate of bone, which normally protects the artery at the level of the eustachian tube, erosive middle ear disease, or previous trauma. Prevention and management of carotid artery injuries in the middle ear are discussed with an applicable case report.

Aneurysm↗
PubMed1993

Treatment of an acoustic neuroma in an only-hearing ear: case reports and considerations for the future.

Current options regarding the treatment of acoustic neuroma in an only-hearing ear include: observation, attempted hearing preservation surgery, and stereotactically guided radiation therapy. A patient who had a left labyrinthectomy for Menière's disease presented 15 years later with a large right acoustic neuroma. Due to anticipated profound deafness, he fit the criteria for cochlear implantation. Promontory stimulation of the left ear was positive. He underwent successful left cochlear implantation with the Nucleus 22-channel device and was successfully rehabilitated. He then underwent translabyrinthine removal of his right-sided 2.5-cm acoustic neuroma. This case is used to illustrate a new option available to those faced with treating a patient with acoustic neuroma in an only-hearing ear. How this approach may fit in with other available options will be discussed.

Cochlear Implants↗
PubMed1993

Preservation of hearing in surgery for acoustic neuromas.

Preservation of hearing was attempted in 161 cases of histologically confirmed acoustic neuroma removed by the senior author between January 1, 1970, and September 30, 1991. There were 136 patients with unilateral tumors; 22 patients had bilateral tumors (neurofibromatosis 2) and underwent a total of 25 procedures. Hearing was initially preserved in 35% of patients with unilateral tumors and in 44% of those with bilateral tumors. Results are reported in terms of pre- and postoperative pure tone average and speech discrimination scores. Surgical access to the tumor was obtained via middle cranial fossa and suboccipital approaches. The latter has been used more often over the past 5 years because of a lower associated incidence of transient facial paresis. Persistent postoperative headaches have been the most common complication following the suboccipital approach. The results of preoperative brain-stem auditory evoked response (BAER) studies were useful in predicting the outcome of hearing preservation attempts. Patients with intact BAER waveform morphology and normal or delayed latencies had a higher probability of hearing preservation in comparison to those with abnormal preoperative BAER morphology.

Adolescent↗
PubMed1992

Postoperative radiographic evaluation after acoustic neuroma and glomus jugulare tumor removal.

The role of postoperative radiographic follow-up of patients after acoustic neuroma or glomus jugulare tumor removal is unclear and not standardized. The incidence of both lesions is rare and recurrence thought to be unusual. However, a patient with an acoustic neuroma arising in the same ear afflicted with a glomus jugulare tumor removed 5 years earlier prompted a retrospective review of 999 acoustic neuroma and 98 glomus jugulare tumor patients. This review helps to determine the role and frequency of postoperative follow-up, not only to assess recurrence of these lesions but to monitor for the possible development of potential clinically silent new lesions.

Adult↗
PubMed1992

Avulsion of the anomalous facial nerve at stapedectomy.

Injury to the facial nerve in an anomalous location overlying the oval window at the time of stapedectomy has rarely been reported. The authors recently have encountered three patients with such injuries. The facial nerve was found at the time of reexploration to run directly over the oval window. A fourth patient was explored primarily for a conductive hearing loss and the same anomalous course was discovered. The purpose of this report is to alert the otologic surgeon to this rare but potentially catastrophic anomaly and to review the pertinent embryology and management of these malformations.

Adult↗
PubMed1992

Defect reconstruction and cerebrospinal fluid management in neurotologic skull base tumors with intracranial extension.

Intracranial extension (ICE) is the spread of tumor into the subarachnoid space through dura or along cranial nerve roots. The single-stage removal of the skull base tumor with its ICE has been confounded by cerebrospinal fluid management and defect reconstruction. The purpose of this report is to review a current protocol for managing the cranial base tumor and its ICE as a unit. The ventricular shunting paper of 1987 is retracted. All tumors were managed at a single stage. Defect reconstruction was size dependent. Ninety-eight neurotologic skull base tumors with ICE were managed from 1971 to 1991. The new protocol was initiated in 1987. Results specific to this group are highlighted. For glomus tumors, cerebrospinal fluid leak rates have been dramatically reduced overall from 14.5% to 4%. The leak rates for nonglomus tumors, overall, have improved slightly. Complications are discussed. The development of this surgical approach protocol improves the functional outcome in patients of surgeons who aspire to disease "cure" rather than "control."

Adolescent↗
PubMed1992

Electrical promontory stimulation in patients with intact cochlear nerve and anacusis following acoustic neuroma surgery.

Anacusis following hearing preservation surgery for acoustic neuroma removal in which the cochlear nerve was preserved has been explained on the basis of neural or vascular compromise. In the absence of pathologic evidence for either theory, a physiologic model was chosen. Electrical promontory stimulation with monitoring of subjective and electrically evoked auditory brainstem responses was undertaken. A positive response to stimulation suggests a vascular impairment of the cochlea sparing the cochlear nerve and spiral ganglion. The absence of response suggests loss of neural integrity at the level of the spiral ganglion or cochlear nerve. Six patients who suffered anacusis following hearing preservation surgery for acoustic neuroma were studied. Data regarding electrical promontory stimulation, auditory brainstem responses, and implications of the possible role of cochlear implantation are discussed.

California↗