Successful treatment of glomus jugulare tumours with gamma knife radiosurgery: clinical and physical aspects of management and review of the literature

PURPOSE: To demonstrate the feasibility of treatment and early outcomes for patients treated with gamma knife radiosurgery (GKR), with or without surgical resection, for glomus jugulare tumours. METHODS: Between January 2007 and November 2008, 10 patients with glomus jugulare tumours were treated with GKR. Eight had prior surgical resection, seven subtotal resection and one total resection. In two cases GKR was the only definitive therapy. Baseline neurological deficits were prospectively recorded and present in 90% prior to GKR. The median tumour size and volume were 4 cc (0.7-10.9 cc). The median marginal tumour dose was 14 Gy (12-16 Gy). Clinical and radiographic outcomes are reported with a median follow-up of 9.7 months. RESULTS: Stereotactic frame placement allowed treatment of all 10 lesions, although 3-point fixation was sometimes required to avoid collisions. No patients developed worsening of symptoms or new neurological complaints after GKR; symptom relief was achieved in 50% of cases. No cases of clinical or radiographic progression were identified. Radiographically, 80% of lesions were stable and 20% showed significant shrinkage. CONCLUSIONS: GKR is an excellent option for patients with glomus jugulare tumours after complete or subtotal resection or at recurrence. Appropriately planned frame placement allows successful treatment delivery without difficulty. GKR improved symptoms, prevented neurological progression and achieved radiographic stability or regression in all cases (AU)

Tympanic membrane perforation repair using AlloDerm.

BACKGROUND: Some patients lack quality autologous tissue for tympanic membrane (TM) grafting. AlloDerm (LifeCell Corp, The Woodlands, TX) is a preserved allograft that has been effective in nonotologic applications. OBJECTIVE: The goal of this study was to investigate AlloDerm in the repair of chronic TM perforations. METHODS: Ten adult chinchillas underwent a controlled, 2-stage procedure for creation and repair of bilateral TM perforations. Myringoplasties were performed. The control side (left) was repaired with autologous fascia; AlloDerm was used in all right ears. Grafts were assessed at 3 to 8 weeks. RESULTS: Complete TM perforation closure was noted in 9 of 10 (90%) control ears and 8 of 10 (80%) AlloDerm-treated ears. Fascia and AlloDerm integrated consistently with host tissues. No variables demonstrated statistical significance. CONCLUSIONS: AlloDerm appeared to be an ideal substitute for grafting of the TM. It was equally effective as fascia. Clinical trials in human beings appear warranted. Potential health care savings are discussed.

Otologic injuries caused by airbag deployment.

Airbags are clearly successful at mitigating injury severity during motor vehicle accidents. Deployment unfortunately has introduced new injury-causing mechanisms. A retrospective review of 20 patients who sustained otologic injuries resulting from airbag inflation was conducted. The most common symptoms were hearing loss in 17 (85%) and tinnitus in 17 (85%). Objective hearing loss was documented in 21 of 24 (88%) subjectively affected ears; this included unilateral and bilateral sensorineural, unilateral conductive, and mixed hearing losses. Ten patients (50%) had dysequilibrium. Four subjects (20%) had a tympanic membrane perforation; each required surgical closure. Ear orientation toward the airbag was found to be associated with hearing loss (P = 0.027), aural fullness (P = 0.039), and tympanic membrane perforation (P = 0.0004). A wide variety of airbag-induced otologic injuries occur and may have long-term sequelae. It is important for health care personnel to be aware of these potential problems.

Investigation of endolymphatic hydrops by electrocochleography in patients with Cogan's syndrome.

We compared auditory and vestibular function between a patient with typical Cogan's syndrome and a patient with atypical Cogan's syndrome. Repeat audiograms demonstrated fluctuating sensorineural hearing loss in the affected ear. Brainstem auditory evoked response testing revealed no abnormalities. Hallpike caloric testing showed a decreased response in the affected ear in the typical case and responses within normal limits in the atypical case. Sinusoidal harmonic acceleration was normal in the typical case, and there was an abnormal phase at 0.01 Hz in the atypical case. Endolymphatic hydrops was investigated by electrocochleography. In both patients, there was an enhancement of the summating potential, with an increased ratio of summating potential to action potential amplitude. This finding is consistent with endolymphatic hydrops.

Otitis externa.

Otitis externa is a broad term for a disease state that includes inflammation or infection of the external auditory canal and auricle. It can range from mild inflammation and discomfort to a life-threatening disease. Treatment of otitis externa is dependent on a thorough understanding of anatomy and physiology of the external ear canal, a knowledge of the microbiology of potential pathogens, and familiarity with clinical presentation, so that an accurate and timely diagnosis can be reached.

Evaluation of residual acoustic schwannoma using gadolinium-DTPA enhanced magnetic resonance imaging with the fat suppression technique.

After subtotal resection of acoustic schwannomas, radiographic evaluation is necessary to evaluate tumor growth. With conventional gadolinium-DTPA T1-weighted magnetic resonance imaging, tumor delineation is often obscured by surgically placed fat. This occurs because fat has the same intensity as enhanced acoustic tumor. T1-weighted magnetic resonance fat suppression techniques can be used to eliminate the strong signal of fat tissue. When this technique is used in combination with gadolinium-DTPA, the definition of pathologic structures is improved in those areas containing large amounts of fat. Twelve patients who had subtotal resection of an acoustic schwannoma underwent gadolinium-DTPA enhanced magnetic resonance imaging using the fat suppression technique. Residual tumors were more conspicuous and had improved margin definition using the fat suppression technique compared to conventional gadolinium-DTPA T1-weighted images. These refinements in magnetic resonance imaging represent a significant advance in the assessment of residual acoustic tumors.

Intraoperative electrocochleography during endolymphatic sac surgery: clinical results.

Thirty-eight patients who underwent endolymphatic shunt surgery with intraoperative electrocochleography were questioned regarding control of symptoms. The average follow-up period was 2 years (range, 7 to 40 months). Sixteen (42%) patients showed improvement in the intraoperative electrocochleography potential, 12 (32%) showed worsening, and 10 (26%) showed no change. Complete or substantial control of dizziness was achieved in 36 (95%) patients, and insignificant control in only 2 (5%) patients. Hearing improvement was noted in 4 (11%) patients, and hearing loss in 13 (34%). No correlation was found between intraoperative electrocochleography improvement and dizziness control. However, three of the four patients who had hearing improvement also had the greatest improvement in intraoperative electrocochleography recording. Intraoperative electrocochleography may help the surgeon more accurately identity the true endolymphatic sac and duct.

Ossiculoplasty with composite prostheses. Overview and analysis.

Aeration of a mucosa-lined tympanic cavity is essential for a functioning middle ear. Extrusions of even the best-designed prostheses occur from abnormal middle ear conditions such as atelectasis, middle ear fibrosis, recurrent cholesteatoma, tympanic membrane perforation, and otitis media. Various polymers have been developed in an attempt to maximize prosthetic biocompatibility and ease of use while minimizing the chance of extrusion. One such polymer is a composite of hydroxyapatite and Silastic, known as Flex H/A. This material has been incorporated into two ossicular prostheses, the Universal Plus and the Causse Flex H/A prostheses. Certainly, refinements will continue to be made in the chemical makeup of the bioceramics in order to achieve optimal biocompatibility. In addition to biocompatibility, cost containment issues have influenced the development of ossicular prostheses. A universal prosthesis eliminates the need to stock multiple designs, thereby reducing the cost to institutions. One of the greatest challenges in the future will be to define the appropriate prosthetic design for optimal sound transmission. Consideration of prosthesis weight, head size, and footplate attachment are future research questions that need to be addressed in a scientific biologic model.

Oscillopsia in patients with loss of vestibular function.

Contrary to standard teaching, many patients with bilateral vestibular loss clearly deny oscillopsia or imbalance in darkness. In an attempt to characterize these patients within the larger population of all patients with bilateral vestibular loss, the rotation and posturography test results of 22 patients with bilateral vestibular loss were reviewed. In addition, dynamic visual acuity was assessed with an eye chart test. There was a poor relationship between oscillopsia and dynamic visual acuity or rotation testing. There were three patterns of response on rotation testing, and loss of high-frequency gain was seen in as many patients who reported oscillopsia as did not. There were some patients with normal gain values at all frequencies tested who reported oscillopsia. It may be that the change in the VOR, rather than the absolute VOR loss, is responsible for the production of oscillopsia. On the basis of this and other studies, treatment strategies for patients with bilateral vestibular loss are suggested.

Fluorescein use in the detection of perilymphatic fistula: a study in cats.

A stained or colored perilymph would be a valuable tool to otologists for the detection of a perilymph fistula. We studied the effect of intravenously injected fluorescein on the inner ear in seven cats. Still and video photography was used to clearly document our findings. Intravenously injected fluorescein appeared within the soft tissue in less than 1 minute and stayed there for at least 3 1/2 hours. Fluorescence around the round window niche resulted from soft tissue (mucosal) fluorescence and extravasation of interstitial fluid (transudate). No fluorescence of perilymph was detected. Because of this, we do not believe intravenously injected fluorescein is useful in the detection of perilymph fistula. Intrathecal injection caused quick and intense staining of labyrinthine fluid.

Use of electrocochleography to monitor antigenic challenge in Menière's disease.

Allergy has been reported as a cause of Menière's disease. King et al. have established the validity of the provocative food test (PFT) for the diagnosis of food allergy. When the PFT is used to test patients with Menière's disease, the test is considered positive if the patient develops aural fullness, hearing loss, increased tinnitus, or dizziness during challenge with the offending food and relief of these symptoms during neutralization. Ferraro et al. have shown that electrocochleography (ECoG) provides an objective indication of subjective symptoms in Menière's disease by demonstrating an increased SP/AP amplitude ratio when the symptoms of aural fullness and hearing loss are present. We present several patients with Menière's disease in whom measurement of the SP/AP amplitude ratio was compared with symptom production during antigenic challenge and neutralization.

Management of metastatic glomus jugulare tumors.

METASTATIC GLOMUS JUGULARE TUMORS (JUGULAR PARAGANGLIOMAS) ARE VERY UNCOMMON: consequently, no single report has been able to accurately describe their biologic or clinical behavior, and there are no established guidelines on caring for patients with these tumors. Identification of metastatic paraganglioma can be difficult because these tumors are known to occur synchronously, many other tumor types appear histologically similar to paragangliomas, and histologically the metastasis may not resemble the primary tumor. Immunohistochemistry, using neuroendocrine markers, and electron microscopy are the two most useful techniques available to identify definitely paragangliomas. A few studies have shown differences in the immunohistochemical staining patterns between benign and metastatic paragangliomas. We reviewed the literature and include two additional cases of metastatic glomus jugulare tumors in this article. We discuss the clinical management of these patients, the importance and usefulness of immunohistochemistry in characterizing these tumors, and their clinical outcomes.

Electromagnetic semi-implantable hearing device: phase I. Clinical trials.

Conventional hearing aids have improved significantly in recent years; however, amplification of sound within the external auditory canal creates a number of intrinsic problems, including acoustic feedback and the need for a tight ear mold to increase usable gain. Nonacoustic alternatives which could obviate these encumbrances have not become practical due to inefficient coupling (piezoelectric techniques) or unfeasible power requirements (electromagnetic techniques). Recent technical advances, however, prompted a major clinical investigation of a new electromagnetic, semi-implantable hearing device. This study presents the details of clinical phase I, in which an electromagnetic driver was coupled with a target magnet temporarily affixed onto the lateral surface of the malleus of six hearing aid users with sensorineural losses. The results indicate that the electromagnetic hearing device provides sufficient gain and output characteristics to benefit individuals with sensorineural hearing loss. Significant improvements compared to conventional hearing aids were noted in pure-tone testing and, to a lesser degree, in speech discrimination. Subjective responses were quite favorable, indicating that the electromagnetic hearing device 1. produces no acoustic feedback; 2. works well in noisy environments; and 3. provides a more quiet, natural sound than patients' conventional hearing aids. These favorable results led to phase II of the project, in which patients with surgically amendable mixed hearing losses were implanted with the target magnet incorporated within a hydroxyapatite ossicular prosthesis. The results of this second-stage investigation were also encouraging and will be reported separately.

Evaluation of the monothermal caloric test.

In 1970, Torok reported that patients with labyrinthine disease showed vestibular recruitment and that patients with retrolabyrinthine disease showed vestibular decruitment on the monothermal caloric test. Other investigators have failed to confirm these findings; however, their studies did not precisely replicate Torok's test procedure. Following Torok's procedure exactly, the monothermal caloric test was administered to normal individuals and to patients with well-documented vestibular lesions. Nine of ten normal persons showed normal responses and one person showed borderline decruitment. Six of eight patients who had lesions of the vestibular nerve or central vestibular pathways showed decruitment. Two patients with active Meniere's disease showed recruitment and one showed asymmetry. Two patients with Meniere's disease who had undergone endolymphatic sac operations showed normal responses. These findings support Torok's claim that the monothermal caloric test discriminates between labyrinthine and retrolabyrinthine vestibular pathology.

Use of bacitracin for neurotologic surgery.

Wound infection, cerebrospinal fluid leak, and meningitis are serious potential complications of neurotologic procedures that transgress the posterior cranial fossa dura. A study of 236 patients was made to determine the effect of perioperative intravenous antibiotics and topical bacitracin irrigation on the incidence of these complications. Of the 236 patients, 170 (72%) underwent translabyrinthine resection of acoustic tumors, while 66 (28%) underwent retrolabyrinthine vestibular nerve section. Patients were divided into four groups: those who received no antibiotics, those who received perioperative intravenous antibiotics only, those who received topical bacitracin irrigation only, and those who received a combination of perioperative intravenous antibiotics and topical bacitracin irrigation. There were no untoward effects of either perioperative intravenous antibiotics or topical bacitracin. The results indicate that bacitracin irrigation reduced the incidence of wound infection from 9% to 2% (p less than 0.05); of cerebrospinal fluid leak from 12% to 5% (p less than 0.04); and of all targeted complications combined from 22% to 9% (p less than 0.006). Furthermore, the topical bacitracin irrigation only group showed a statistically significant reduction in wound infections compared to the perioperative intravenous antibiotic only group (p less than 0.02). The incidence of meningitis was statistically unaffected by any of our treatment protocols.

Normal hearing in patients with acoustic neuroma.

We reviewed the cases of 614 patients who had operation for acoustic neuroma. In 38 cases, hearing was either normal or decreased symmetrically. Almost all patients had unilateral otologic complaints. All patients with unilateral otologic complaints should be evaluated for acoustic neuroma even if results of routine audiometry are unremarkable.

Neuromas of the skull base.

Ten skull-base neuromas treated at the Otology Group P.C. are presented. Each case is reported in detail. The method by which preoperative diagnosis was made is reviewed. Specific attention is paid to distinguishing these tumors from chemodectomas. Presenting signs and symptoms are enumerated. Operative--especially postoperative--management is discussed in detail.

Open mastoid procedures: contemporary indications and surgical technique.

The history of the management of chronic ear disease with and without cholesteatoma is dominated by a canal wall down philosophy. The implication is that such an open procedure insures disease control and an uncomplicated future. In point of fact, problem canal wall down procedures can be fraught with as many serious complications as their more controversial canal wall up counterpart is alleged to propagate. Such problem cavities most commonly result from poor execution of basic technique. The objective of this paper is to identify what constitutes a problem cavity and to describe the authors' techniques to avoid such difficulties. A technique has evolved which not only eradicates disease, but which is self-cleansing and of minimal impact on the patient's lifestyle. The authors' experience with canal wall down procedures is reviewed.