Spontaneous cerebrospinal fluid leakage and middle ear encephalocele in seven patients.

Isolated cases of spontaneous cerebrospinal fluid (CSF) leakage with and without middle ear encephalocele have been reported. These leaks are usually accompanied by episodes of recurrent meningitis, hearing loss, or chronic headache. In this article, we report seven new cases of spontaneous CSF leakage. Six of these patients had conductive hearing loss and serous otitis media, and three had recurrent meningitis. Prior to a definitive diagnosis, six patients had received myringotomy tubes, which produced profuse clear otorrhea. Three patients had positive beta-2 transferrin assays. Computed tomography and magnetic resonance imaging confirmed a defect in the temporal bone tegmen. A combined transmastoid and middle fossa surgical approach with a three-layer closure was used to repair the tegmen defect. All patients had a lumbar drain placed prior to surgery. In addition to describing the seven new cases, we review the history of CSF leakage and discuss diagnostic methods, surgical findings, and our recommendations for management.

Dexamethasone pharmacokinetics in the inner ear: comparison of route of administration and use of facilitating agents.

There is growing otologic interest in treating inner ear disorders, such as sudden sensorineural hearing loss and acute or unremitting Meniere's disease, with intratympanic dexamethasone (IT-DEX). Although anecdotally reported, there are no scientific clinical papers and few prior laboratory research publications on the subject. This study compares perilymph dexamethasone concentrations after systemic and intratympanic administration and assesses the role of 3 potential transport facilitators of IT-DEX into perilymph. Forty guinea pigs (79 ears) were randomly separated into 5 groups. Dexamethasone levels were measured by radioimmunoassay. IT-DEX resulted in higher perilymph steroid levels than intravenous dexamethasone (P < 0.05). Histamine facilitator resulted in significantly higher perilymph steroid levels than IT-DEX alone (P < 0.05). Neither hyaluronic acid nor dimethylsulfoxide was a potent facilitator. This study demonstrates that IT-DEX administration results in superior perilymph levels within 1 hour of administration and does not result in systemic absorption. Histamine is a potent facilitating agent. The clinical implications are considerable.

Microsurgical removal of a vestibular schwannoma after stereotactic radiosurgery: surgical and pathologic findings.

OBJECTIVE: The objective of this study was to provide objective evidence of the enhanced difficulty of preserving the facial nerve in patients who need microsurgery after failed stereotactic radiosurgery (SRS) of vestibular schwannoma. STUDY DESIGN: This study was a retrospective case review. SETTING: A tertiary care referral center was the setting for the study. PATIENTS: The authors present a case of a young woman with a vestibular schwannoma that enlarged 2 years after treatment with SRS. INTERVENTION: Microsurgery via the translabyrinthine approach was used. RESULTS: At surgery, extensive scarring between the facial nerve and tumor capsule was seen, and the nerve could not be identified at all beyond several millimeters proximal to the porus acusticus. Adhesions of the tumor to the ninth and tenth cranial nerves, the brain stem, and the anterior inferior cerebellar artery were also markedly increased. Histologic examination confirmed fibrotic adhesions surrounding the facial nerve. CONCLUSIONS: The unusual degree of fibrosis, scarring, and adhesions of the tumor to the surrounding structures after SRS made microsurgical removal of the tumor difficult and preservation of the facial nerve impossible.

Complications of gold weight eyelid implants for treatment of fifth and seventh nerve paralysis.

Complications occurred in six patients after gold weights were implanted into the upper eyelid tissues for fifth and seventh nerve palsies. These complications included implant infection without extrusion (in one patient); entropion with trichiasis and presumed inflammatory reaction to the gold weight material (in one patient); upper eyelid distortion and poor eyelid contour with corneal ulceration and scarring (in one patient); significant residual lagophthalmos with exposure keratitis (in one patient); and blepharoptosis obscuring the pupillary access (in two patients). Resolution of the complications required 1. implant removal in four of six patients without reinsertion of a second weight, 2. recession of the retractors of the upper eyelids with medial and lateral canthoplasty (in four patients), and 3. permanent tarsorrhaphy (in one patient). The authors conclude that complications may be minimized by careful preoperative determination of the optimum implant size, weight, and placement within the eyelid as well as meticulous attention to the surgical technique of implantation. The use of other eyelid protective procedures is often necessary to augment corneal protection especially in patients with combined fifth and seventh cranial nerve palsies. Endogenous implant infection without extrusion of the gold weight may be distinguished from presumed inflammation due to gold allergy by clinical response to antibiotics in the former and requirements of steroids or removal of the implant in the latter.

Persistent trigeminal artery as a cause of dizziness.

Complaints of vertigo and dizziness are common problems referred to otolaryngologists for evaluation. Awareness of uncommon causes of dizziness increases the physician's ability to diagnose and treat these patients. We present the case of a middle-aged woman who presented with episodes of vertigo and symptoms suggestive of vertebrobasilar insufficiency. These symptoms were the result of a persistent trigeminal artery (PTA) and occlusive carotid artery disease. A PTA is a carotid-basilar anastomosis that has been reported to be demonstrated on 0.1% to 0.6% of all cerebral angiograms. Persistence of this vessel usually leads to hypoplasia or agenesis of the ipsilateral posterior communicating artery, and leaves the internal carotid artery as the main source of blood supply to the region of the upper brainstem. The appearance and clinical significance of this unusual condition will be discussed.

Endoscopic closure of the eustachian tube for repair of cerebrospinal fluid leak.

Techniques to repair cerebrospinal fluid (CSF) leak through the eustachian tube (ET) include temporary or permanent CSF diversion; middle fossa craniotomy and packing of the ET from above; and packing of the ET from behind, through the middle ear. We report a case of endoscopic closure of the ET in the nasopharynx (the front). A 26-year-old woman underwent a translabyrinthine removal of a 4.5-cm vestibular schwannoma. One year later, she developed CSF rhinorrhea and meningitis. Attempts at control of this leak included traditional approaches mentioned previously (shunting, middle fossa, middle ear packing). The leak recurred 2-3 months after each procedure. An endoscope was used transnasally to expose the ET orifice, which was incised, inverted, and cauterized. She has remained free of leak for 1 year. Our success in this difficult case suggests that this is a useful procedure for treatment of CSF rhinorrhea originating in the posterior fossa. Greater experience is needed to verify its long-term effectiveness and utility as a primary procedure for the treatment of CSF rhinorrhea.

Management of hydrocephalus resulting from acoustic neuromas.

Patients with large acoustic neuromas may have secondary obstructive hydrocephalus and occasionally significant neurologic deficit develops. At the House Ear Clinic, we have managed patients with hydrocephalus by translabyrinthine tumor removal without preoperative ventriculoperitoneal shunting. Forty-three patients with documented hydrocephalus who underwent acoustic neuroma removal have been reviewed. Six patients had neurologic deficit resulting from raised intracranial pressure before surgery. In each of these six cases, the deficit resolved after tumor removed without requiring shunting. Two patients had had ventriculoperitoneal shunts inserted because of neurologic deficit before referral for tumor removal. Two other patients underwent postoperative shunting for neurologic deficit --one at 2 weeks and one at 2 years. Cerebral or cerebellar herniation was not noted in any case. Cerebrospinal fluid leak occurred in five patients (11.6%) and culture-positive meningitis in two patients (4.6%). We conclude that decompression by translabyrinthine tumor removal is a safe method of management for patients with hydrocephalus resulting from large acoustic tumors.

Predicting long-term facial nerve outcome after acoustic neuroma surgery.

Although anatomic preservation of the facial nerve is achieved in nearly 90% of reported cases after acoustic neuroma surgery, postoperative long-term facial function is of most concern to the patient. This study examines long-term facial nerve function in relation to the immediate postoperative function and the function at time of discharge from the hospital. Subjects included 515 patients who underwent primary acoustic neuroma removal at House Ear Clinic from 1982 through 1989 and who had normal preoperative facial function, an intact facial nerve after surgery, and a House-Brackmann facial nerve grade available immediately postoperatively, at time of hospital discharge, and at least 1 year postoperatively. Rate of acceptable facial function (House grades I-IV) differed significantly (p < or = 0.001) at the three postoperative time intervals: 85.2%, immediate; 73.6%, discharge; 93.8%, long-term. Of those with good immediate function (grades I-II), 98.6% had acceptable long-term function. Of those with poor immediate function (grades V-VI), 69.8% had acceptable long-term function. We conclude that facial nerve recovery after acoustic neuroma surgery is characterized by slight deterioration in the immediate postoperative period, but subsequent improvement in the long-term. Patients can be reliably counseled that acceptable function immediately after surgery is associated with a favorable long-term outcome; poor function immediately after surgery, despite an intact nerve, has a more guarded prognosis.

Extended middle fossa and retrolabyrinthine approaches in acoustic neuroma surgery: case reports.

Hearing conservation surgery for small acoustic neuromas is well accepted. At present, two approaches are primarily used: the suboccipital and the middle fossa. The middle fossa approach to the internal auditory canal has the advantage of using bony landmarks to identify and protect the facial nerve. Because of anatomic constraints presented by the superior semicircular canal however, its uses are limited to intracanalicular tumors or tumors protruding only slightly into the cerebellopontine angle. By extending the approach through the superior semicircular canal, a wide access to the cerebellopontine angle can be safely obtained. In this study three procedures, two through the superior semicircular canal and one through the posterior semicircular canal, were utilized for hearing conservation surgery. By immediately sealing off the canal ends, hearing preservation was accomplished in two out of three of these cases. The dictum that labyrinthine opening invariably leads to anacusis should be reconsidered. By utilizing approaches through the semicircular canal, it is possible that morbidity from this surgery may be reduced.

Lipomas of the internal auditory canal.

Intracranial lipomas are rare tumors which may occur in the cerebellopontine angle (CPA) or internal auditory canal (IAC). Although seemingly innocuous in other parts of the body, lipomas within the CPA and IAC often involve the surrounding cranial nerves, making attempts at hearing conservation largely unsuccessful. In an attempt to differentiate the IAC lipoma from the more commonly found acoustic schwannoma, the preoperative imaging studies (magnetic resonance and computerized tomography) on five previously unreported cases of IAC lipomas were evaluated. Based on these studies, features were determined that may allow the surgeon to diagnose IAC lipomas preoperatively. These features will be discussed, as well as the surgical and pathological findings.

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.

Sudden hearing loss due to AIDS-related cryptococcal meningitis--a temporal bone study.

We have presented the clinical history and temporal bone findings in a patient who manifested sudden hearing loss, and who subsequently was found to have cryptococcal meningitis associated with AIDS. The histopathologic findings are similar to earlier reports in patients without AIDS. Because cryptococcal infection is so much more common in AIDS patients than in the general population, it must be considered a causative factor when presented with an AIDS patient with progressive or sudden hearing loss. This offers the patient a chance for timely and effective treatment.

Transcanal infracochlear approach to the petrous apex.

Computerized tomography and magnetic resonance imaging have now made it possible to reliably differentiate cholesteatoma from cholesterol granuloma of the petrous apex. The treatment for cholesteatoma is complete surgical excision when possible, whereas cholesterol granuloma needs only adequate drainage for control. A new transcanal infracochlear approach for drainage of cholesterol granuloma involving the anterior petrous apex is described. Absolute measurements from 10 cadaveric temporal bones were obtained to determine the distances between the cochlea, jugular bulb, carotid artery, and facial nerve. In all specimens the petrous apex was entered without invading the cochlea, carotid, or jugular bulb. Advantages of this technique include a more direct route to the petrous apex, dependent drainage, and preservation of the normal hearing mechanism, including the tympanic membrane. Clinical indications for this technique include failure of other treatment approaches and a high jugular bulb obstructing an infralabyrinthine approach. Experience to date shows that patients experience little difficulty from the procedure.

Middle fossa decompression of the internal auditory canal in acoustic neuroma surgery: a therapeutic alternative.

Unilateral acoustic neuromas in only-hearing ears and bilateral acoustic neuromas (NF-2) are separate entities, but both pose a common problem because surgical removal has the potential to leave the patient totally deafened. A middle fossa decompression of the internal auditory canal (IAC) was performed in 8 patients (5 with NF-2 tumors and 3 with neuromas in an only-hearing ear). In 5 of the 8, the speech discrimination scores at the 6-month follow-up were better than preoperative scores. After 6 months, however, hearing regressed at variable rates. Although not a definitive therapeutic treatment, decompression of the IAC appears to improve and perhaps prolong useful hearing, which gains valuable time for rehabilitation. Rigid follow-up by computed tomography scans or magnetic resonance imaging is essential.

A review of acoustic tumors: 1983-1988.

This is a review of the English literature relative to acoustic tumors from 1983 through 1988. In January of 1984, a similar article was published in this journal which reviewed the literature from 1979 through 1982. We have selected what we consider the most important articles from the hundreds that were published on this subject. Many other significant papers are not discussed. The material is presented in 11 categories: diagnosis, histopathology, treatment, hearing preservation, facial nerve preservation and repair, von Recklinghausen's disease and bilateral tumors, nonacoustic cerebellopontine angle tumors, instrumentation, basic research, complications of surgery, and miscellaneous topics. In each section the articles are briefly reviewed, and sometimes our personal point of view is expressed.