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Biomedical subjects

C Shelton

Publications and source records attributed to C Shelton.

At least 55 records · Page 3Linked to original sources
PubMed1993

Hearing preservation in bilateral acoustic neuroma surgery.

Patients with neurofibromatosis type 2 (NF2) develop bilateral acoustic neuromas, but preservation of hearing while achieving tumor removal may present several unique problems. Our philosophy regarding hearing preservation attempts in these cases has evolved over several decades. The outcome of hearing preservation surgery using the middle cranial fossa approach for 13 procedures in 10 patients with NF2 is presented. There were 12 total tumor removals and one partial tumor removal. Two ears retained good postoperative hearing, three had serviceable hearing, four had measurable hearing, and four had no measurable hearing. Both cases with tumors 2 cm or larger retained no hearing. For the 12 total tumor removals, the rate of hearing preservation was 67 percent. Of four total removals with long-term follow-up, two retained good or serviceable hearing. The rate of hearing preservation is similar to that found in our series of unilateral acoustic neuroma surgeries. Based on these findings, hearing preservation surgery is recommended for patients with NF2 who have acoustic neuromas 1.5 cm or smaller.

Adolescent↗
PubMed1992

Middle fossa vestibular neurectomy in retrolabyrinthine neurectomy failures.

Retrolabyrinthine vestibular nerve section is an important treatment option in patients with refractory, incapacitating vertigo. However, an indistinct cleavage plane between the cochlear and vestibular portions of the eighth cranial nerve may result in incomplete sectioning of the superior and inferior vestibular nerve fibers. We describe 11 patients in whom middle fossa vestibular neurectomy was performed following failure of a retrolabyrinthine vestibular neurectomy. A successful postoperative outcome from this revision surgery was obtained in six of 11 patients on follow-up evaluation. Patients in whom infrared video electronystagmography showed persistent function of the inferior vestibular nerve following retrolabyrinthine vestibular nerve section had a better response to middle fossa vestibular neurectomy than those with no measurable residual vestibular function. Because it provides access to the vestibular nerves where there is separation from the cochlear nerves distal to the previous section, we feel that the middle fossa vestibular neurectomy is the procedure of choice in selected patients who fail retrolabyrinthine neurectomy.

Adult↗
PubMed1992

Otosclerosis. Treating progressive hearing loss in young adults.

When a patient presents with bilateral progressive hearing loss and has a family history of hearing loss, otosclerosis should be placed high on the list of possible causes. Primary care physicians should determined whether the hearing loss is conductive or sensorineural with otologic examination and tuning-fork evaluation. Unless there is an obvious reversible cause for the progressive hearing loss, the patient should be referred to an otolaryngologist for more intensive otologic and audiologic examination. The patient's principal concern is the ability to hear and comprehend the spoken word in normal circumstances. Fortunately, most patients can be rehabilitated with surgery or a hearing aid. Fluoride treatment may have a significant role in preventing further hearing loss from otosclerosis.

Adolescent↗
PubMed1992

Selection of surgical approaches for meningiomas affecting the temporal bone.

The varied locations of meningiomas within the temporal bone require a wide array of neurotologic approaches to accomplish complete resection with minimal morbidity. We reviewed 56 consecutive patients with temporal bone meningiomas. The six surgical approaches are described with regard to site of lesion, morbidity of procedure, and long-term patient outcome. Recommendations are made for selection of surgical approach. Hearing preservation was attempted in 25%. Middle fossa tumor removal was performed in nine patients (16%), retrosigmoid (suboccipital) in five patients (9%), translabyrinthine in 24 patients (43%), transcochlear in 15 patients (27%), infratemporal fossa in two patients (4%), and retrolabyrinthine in one patient (2%). Overall, meningioma surgery has higher morbidity, poorer facial nerve outcome, and higher recurrence rates than acoustic neuroma surgery. Thirteen percent of patients were unable to resume full preoperative activities after their surgery. Facial nerve transection occurred in 9% of the cases, and 83% of cases with more than 1 year followup had satisfactory or intermediate facial function (grades I to IV). Meningiomas of the temporal bone are insidious and aggressive lesions. Particular care is required to select the surgical approach appropriate for location, level of hearing, and the anatomic structures involved. Patients must be realistically counseled about the surgical morbidity and long-term outcome associated with each approach.

Facial Nerve↗
PubMed1992

Hearing preservation following surgical removal of meningiomas affecting the temporal bone.

It is a common clinical impression that preservation of hearing is more often achieved when removing a meningioma than a similarly sized acoustic tumor. However, relatively few reports have focused on postoperative hearing results after meningioma removal, and detailed audiometric data are not commonly provided, particularly in the neurosurgical literature. During the past 16 years, 56 meningiomas affecting the temporal bone have been surgically removed at the House Ear Clinic. Hearing preservation was attempted in 16 (29%) of the 56 cases, and these were the focus of this study. The primary presenting symptom was otologic in 67% of these cases, including hearing loss as the primary symptom in 27%. Measurable postoperative hearing was present in 11 (92%) of 12 patients with postoperative audiograms available, and 8 (67%) of 12 patients had good hearing postoperatively. Hearing was preserved near the preoperative level (within 10 dB speech reception threshold and 15% speech discrimination) in 75% of cases.

Aged↗
PubMed1992

Labyrinthotomy with streptomycin infusion: early results of a multicenter study. The LSI Multicenter Study Group.

Early results for hearing and vertigo are reported for 47 labyrinthotomies with streptomycin infusion (LSI) by 13 coinvestigator-surgeons. Sixty-eight percent of patients had worse hearing after surgery (10 dB or 15% word recognition). Patients with a preoperative pure-tone average better than or equal to 40 dB appeared to suffer less postoperative hearing loss than those with a greater preoperative deficit. Severe to profound postoperative hearing loss was experienced by 27 patients (57%), all of whom had preoperative pure-tone averages worse than 40 dB. Opening the endolymphatic space was associated with a deleterious effect on hearing. Because of persistent vertigo, 17 percent of patients required a secondary procedure during the period of observation. These early results indicate that LSI is associated with a significant risk of postoperative hearing loss. Of the 13 coinvestigator-surgeons, four have stopped using LSI, while one considers his results satisfactory. The remaining surgeons have taken an intermediate position and feel it is useful in selected cases. Longer follow-up is required to judge the efficacy of LSI for controlling vertigo. We are currently studying these long-term results.

Adult↗
PubMed1992

Acoustic tumors: effect of surgical removal on tinnitus.

Tinnitus is common in patients with acoustic tumors and may be the initial symptom leading to diagnosis. We might anticipate that tumor removal would alleviate preoperative tinnitus. However, few have studied this systematically. Further, the effect of tumor removal in those with no preoperative tinnitus has rarely been examined. In this study, a questionnaire was sent retrospectively to patients who had undergone surgical removal of an acoustic tumor, addressing the characteristics of tinnitus, and asking whether surgery had directly affected tinnitus. A total of 134 questionnaires were returned. Those who indicated preoperative tinnitus tended to show small but statistically significant improvements in the perceived severity of the tinnitus after surgery, although the symptom rarely resolved entirely. Those with no preoperative tinnitus have an approximately 50 percent chance of developing it following surgery.

Adult↗
PubMed1992

Hearing preservation in acoustic tumor surgery.

Preservation of hearing is a realistic goal, possible through the retrosigmoid or middle fossa surgical approaches. The best candidates have small tumors and good preoperative hearing. Preoperative ABR, ENG, and imaging characteristics may help prognosticate chances for hearing preservation. Hearing rarely improves after surgery, and some have noted a decline in the preserved hearing over time. With the introduction of gadolinium-enhanced magnetic resonance imaging, a larger number of small acoustic tumors are being diagnosed before hearing has been significantly affected. These patients benefit from this early diagnosis and are the best candidates for hearing preservation surgery.

Correction of Hearing Impairment↗
PubMed1992

Middle fossa approach for acoustic tumor removal.

The middle fossa approach is well suited for the removal of small acoustic tumors with possible hearing preservation. The most appropriate candidates have tumors with less than 5 mm extension into the cerebellopontine angle and good preoperative hearing (speech reception threshold less than or equal to 30 dB, speech discrimination score greater than or equal to 70%). Measurable postoperative hearing can be preserved in 31% to 59% of patients, and normal or near normal facial function occurs in 86% to 89%. Serious postoperative complications are rare with this approach. With the advent of gadolinium-enhanced MRI, it is now possible to diagnose acoustic tumors reliably when small and before hearing has been significantly affected. The middle fossa approach provides excellent access for the removal of these small tumors.

Craniotomy↗
PubMed1991

Cochleosacculotomy revisited. Long-term results poorer than expected.

Cochleosacculotomy has been described as a simple, efficacious treatment for relief of vertigo in patients with Meniere's disease in whom medical therapy has failed. We reviewed records of 11 elderly patients with good vestibular function who were thought to be ideal candidates for this procedure. Average follow-up was 17 months. Contrary to previous reports, long-term control of vertigo was poor, and more than 80% of the patients suffered a significant hearing loss from this procedure. Four of 11 patients required a second surgical procedure to control their vertigo. Audiometric measures revealed statistically significant postoperative increases in puretone thresholds at all frequencies and speech reception threshold, and a decrease in discrimination scores. Based on the results of this study, we no longer plan to use cochleosacculotomy for the treatment of elderly patients with Meniere's disease.

Adult↗
PubMed1991

Intratemporal facial nerve hemangiomas.

Facial nerve hemangiomas are benign vascular tumors that arise within the temporal bone and have a histologic appearance similar to both cavernous hemangiomas and vascular malformations. In contrast to facial nerve schwannomas, these are extraneural tumors that cause symptoms by compression and tend to produce deficits when very small in size. We report our experience at the House Ear Clinic with 34 patients having these nonglomus intratemporal vascular tumors. Hemangiomas arising in the internal auditory canal tend to produce a progressive sensorineural hearing loss and are demonstrated with magnetic resonance imaging (MRI), whereas those at the geniculate ganglion are usually first seen with facial nerve symptoms and may require high-resolution computerized tomography (CT) for detection. Facial electromyography is helpful in establishing the diagnosis. Because of their extraneural nature, early diagnosis can permit removal of the tumor with preservation of facial nerves in some patients.

Adult↗
PubMed1991

Tympanoplasty: to stage or not to stage.

No unanimity of opinion exists in regard to staged operations in tympanoplasty. The controversy centers around the degree to which one should attempt to obtain hearing improvement in badly diseased ears. The major factor is the extent of the mucous membrane disease. We review the history of staging, the mucous membrane indications for staging, and the variations involved in canal-wall-down (CWD) procedures. The opinions of nineteen other otologists also are presented, nine of whom do not regularly or ever stage tympanoplasty.

Humans↗
PubMed1991

Facial nerve monitoring in acoustic tumor surgery.

Anatomic and functional preservation of the facial nerve during acoustic tumor surgery remains a primary goal. Intraoperative electromyographic facial nerve monitoring with auditory feedback has enabled the surgeon to more readily achieve this goal. We compared a group of monitored translabyrinthine acoustic tumor removals (N = 89) to a similar unmonitored group (N = 155) in regard to facial nerve function. Function was assessed immediately postoperatively, at time of discharge, and at 1 year postoperatively using the House six-point scale. Results were grouped as satisfactory, intermediate, or poor and were analyzed by tumor size. Facial nerve results were better at all time intervals in the monitored groups, although the difference was not statistically significant at the 1-year interval. There was no difference between monitored and unmonitored patients in the subgroups with tumors smaller than 2.5 cm in diameter. This study supports the usefulness of intraoperative facial nerve monitoring in improving facial nerve results, particularly in larger tumors.

Adult↗
PubMed1991

The treatment of small acoustic tumors: now or later?

Prior to the advent of microneurosurgery, the operative mortality for acoustic tumor removal was high and management often consisted of observation until sufficient symptoms warranted removal. The treatment of these tumors has evolved, and recent introduction of gadolinium-enhanced magnetic resonance imaging (MRI) allows the diagnosis of very small intracanalicular acoustic tumors before hearing has been significantly affected. For such tumors, some surgeons advocate the premicrosurgical philosophy of observation rather than removal. Our results of small acoustic tumor removal with attempt at hearing preservation were reviewed. From 1961 to June 1989, 39 acoustic tumors 0.5 cm or less were removed by the middle fossa approach. Measurable hearing was preserved in 67%, and facial function 1 year postoperatively was normal or nearly normal in 97%. There was no other permanent operative morbidity. Given our results, early surgical removal of small acoustic tumors is advocated.

Adolescent↗
PubMed1991

Glomus tympanicum tumors: a clinical perspective.

Since Guild first discovered glomus bodies in the middle ear, the diagnostic evaluation and therapy of glomus tympanicum tumors have remained challenging. This study describes 73 cases diagnosed as glomus tympanicum tumors over the past 30 years. During this period, imaging techniques have markedly improved, and surgical approaches have evolved and been refined. These 73 cases were reviewed from a clinical perspective involving presentation, diagnostic evaluation, and therapeutic management. Pulsatile tinnitus was the primary symptom in over half the patients, followed by hearing loss in one third. The physical exam rarely revealed a circumferential view of the lesion, emphasizing the necessity of further diagnostic evaluation. High-resolution computerized tomography (CT) is currently the radiographic study of choice. A transmastoid surgical approach with extended facial recess was most commonly employed. Extension to the jugular bulb or internal carotid was rare, and no intraoperative complications of catecholamine secretion were noted. Postoperative complications were few, and the overall residual/recurrence rate was less than 5%. Additional clinical insights may assist in the management of these rare but fascinating tumors.

Adult↗
PubMed1991

Basic principles and clinical applications of tympanometry.

This article presents an overview of tympanometric measures using a 226-Hz probe tone, with an additional focus on complex admittance measures at 678 Hz and an introduction to multiple frequency tympanometry. Basic principles underlying all admittance measures are presented. The clinical implementation and interpretation of tympanometry is discussed.

Acoustic Impedance Tests↗
PubMed1990

Hearing improvement after acoustic tumor removal.

Hearing improvement after removal of an acoustic tumor is an uncommon occurrence. Hearing improvement was observed in 8.5% of acoustic tumor removals performed using the middle fossa approach in an attempt to preserve hearing. Improvement in speech discrimination occurred most frequently and was of greatest magnitude compared with changes in the speech reception threshold or pure-tone average. No preoperative factors were predictive of postoperative hearing improvement. Findings support the conclusion that candidates for hearing preservation surgery should be chosen on the merits of their existing preoperative hearing and not on the basis of anticipated improvement.

Adult↗