Osteomas of the internal auditory canal: a report of two cases.

OBJECTIVES: To determine the optimal medical or surgical treatment of osteomas of the internal auditory canal (IAC) as well as their growth characteristics. STUDY DESIGN: Information was obtained from case histories, images from computed tomography and magnetic resonance imaging, surgical and pathologic findings, and long-term clinical results. METHODS: Two patients, along with 10 additional patients reported in the literature, with osteomas of the IAC with varying symptoms were studied. Clinical history, audiometric and vestibular test results, and radiographic studies were reviewed on all patients. Histopathologic examination of the surgical specimens confirmed the presence of osteomas. The clinical outcomes were studied to determine if the preoperative symptoms had resolved. RESULTS: Eight of 12 patients underwent surgical removal of their IAC osteomas. Three of eight patients had total resolution of all symptoms. Three patients had improvement of their sensorineural hearing loss. Five patients had resolution of their dizziness. Four patients noted resolution of their tinnitus. In the absence of auditory symptoms, vestibular symptoms may be controlled with medical therapy. Long term follow-up of the two patients discussed showed little or no growth over a 4- to 5-year period. CONCLUSIONS: Surgical intervention may be warranted to remove an osteoma of the IAC if symptoms are present. Patients should be made aware that symptoms may or may not improve. Continuation of symptoms may be a result of chronic compression of the auditory and vestibular nerves.

Analysis of patients with persistent dizziness after vestibular nerve section.

Vestibular neurectomy can be an effective operation for the control of persistent dizziness refractory to medical treatment or even endolymphatic sac surgery. Past studies have reported favorable results, creating an almost deceptive impression of the procedure's success rate. However, not all patients will respond favorably. Some will continue to have significant postoperative disequilibrium and, worse yet, persistent vertigo. To analyze the reasons for continued problems, 142 patients undergoing various surgical approaches employed to divide the vestibular nerve (retrolabyrinthine, middle fossa, retrosigmoid and translabyrinthine) were retrospectively, reviewed. Twenty-nine patients (20%) continued to have significant dizziness despite vestibular neurectomy. The reasons for failure were incomplete vestibular nerve section, poor central nervous system compensation, new vestibular disease in the opposite ear, obstructive anatomy, the presence of other central nervous system diseases, and unknown causes. This paper will detail the advantages and disadvantages of various vestibular neurectomy approaches and will present recommendations for further treatment of this difficult-to-manage group of patients.

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.

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.

Transcochlear transtentorial approach for removal of large cerebellopontine angle meningiomas.

Meningiomas of the cerebellopontine angle (CPA) most often arise from the posterior surface of the petrous pyramid and may extend along the dura to involve the tentorium. Petroclival meningiomas often involve Meckel's cavity and the tentorium. It is impossible to completely remove these large lesions with extension to the supratentorial region by conventional surgical approaches to the CPA such as the suboccipital, middle fossa, or translabyrinthine routes. If total tumor resection is not accomplished, recurrence inevitably follows. A transcochlear approach and actual excision of a large portion of the tentorium allows wide exposure to these large CPA and petroclival meningiomas with supratentorial extension. Thirty-three CPA meningiomas were reviewed from 1976 to 1991. Fourteen patients had tumor extension not only into Meckel's cavity but to the supratentorial region. Ten patients had complete tumor removal, whereas subtotal removal was associated with cavernous sinus invasion. The surgical technique is described in detail with accompanying illustrations. Preoperative symptoms, medical imaging scans, results, and complications are discussed.

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.

Hearing loss and pneumococcal meningitis: an animal model.

Clinical studies of predisposing factors in the development of hearing loss secondary to bacterial meningitis have produced conflicting results. An animal model of meningogenic labyrinthitis was developed for more precise study of these parameters. Rabbits were inoculated intrathecally with 10(5) pneumococci to induce meningitis. Hearing thresholds were measured using auditory-evoked responses to 1 kHz, 10 kHz, and click stimuli before infection and every 12 hours thereafter. Profound deafness occurred in all subjects at an average of 48 hours following infection. The incidence and severity of hearing loss was strongly correlated with the duration of meningitis. Temporal bone histology revealed acute inflammation of all perilymphatic spaces including the cochlear aqueduct. This model demonstrated that the risk and severity of hearing loss increase with the duration of meningitis and suggested that the cochlear aqueduct is an anatomic pathway for the extension of infection from the cerebrospinal fluid to the cochlea. The implications for therapy in humans is discussed.

Cranial nerve preservation in lesions of the jugular fossa.

The most significant objection to the proposal of lateral transtemporal cranial base surgery for the treatment of jugular foramen tumors is the perceived lasting morbidity attendant to aggregate cranial nerve loss. As techniques become more standardized and earlier diagnosis generates smaller tumors for treatment, outcome has become more predictable. Surgery has become the recognized management preference for these cranial base lesions. The purpose of this article is to assess the role of surgery in the treatment of jugular foramen lesions, as well as to review some of the technical highlights of conservation surgery, its clinical prerequisites, and reasonable expectations. We review 100 lateral skull base surgical cases of lesions involving the jugular foramen. The majority of these lesions--77 of 100--were paragangliomas. For these glomus tumors, cranial nerve preservation correlated well to tumor size and location. The diversity of the remaining 23 cases prevented any substantive conclusions.

Leiomyosarcoma of the trachea. Case report.

Leiomyosarcoma of the trachea is a rare primary tumor of the upper airway. Twelve cases have been reported in the English-language literature. Our experience with a patient with leiomyosarcoma of the cervical trachea is presented. The classic symptoms, diagnosis, and surgical management of this case are contrasted with those of the previously reported cases. The surgical technique used for our patient, primary tumor resection with skin grafting and placement of a Montgomery Laryngeal Stent, is a unique and effective treatment.

An analysis of the retrolabyrinthine vs. the retrosigmoid vestibular nerve section.

Vestibular neurectomy is gaining widespread acceptance as a primary means of controlling medically refractory vertigo. However, debate continues over the adequacy of vestibular neurectomy within the cerebellopontine angle, long-term control, and the most appropriate surgical approach. To address these issues, we retrospectively reviewed 118 patients who underwent vestibular neurectomy between October 1984 and January 1988. Forty-two patients who underwent a retrolabyrinthine approach and 44 patients who underwent a retrosigmoid approach completed a written questionnaire and provided a recent audiogram. According to American Academy of Otolaryngology-Head and Neck Surgery guidelines, complete or substantial vertigo control was achieved and maintained in 95% of patients in both surgical groups. Hearing, tinnitus, and fullness results over the long term are variable. The advantages and disadvantages of the various vestibular neurectomy approaches will be detailed. On review of our results and surgical experience, we now prefer the retrosigmoid approach.

Conservation surgery for glomus jugulare tumors: the value of early diagnosis.

The results of lateral cranial base surgery for glomus jugulare tumors are gratifying when normal anatomy and function can be preserved. The goal of conservation surgery is to preserve normal ear anatomy and cranial nerve function. In general, conservation surgery is tumor-size dependent. Thus, excellent states of functional recovery depend upon accurate early diagnosis. This paper reviews the technical aspects of transtemporal conservation skull base tumor surgery while also reviewing our experience with nearly 100 glomus jugulare patients. Adjuvants to early diagnosis will be highlighted from a review of presenting symptoms, clinical signs, and related diagnosis. Our objective is to provoke a high index of suspicion in physicians charged with the responsibility of diagnosing these tumors. Diagnostic guidelines are proposed.

Meniere's syndrome and endolymphatic hydrops. Double-blind temporal bone study.

A systematic double-blind assessment of case histories and histopathologic findings in temporal bones in the collection at the Massachusetts Eye and Ear Infirmary was performed to test the hypothesis that clinical Meniere's syndrome is associated with endolymphatic hydrops demonstrated histopathologically at death. Thirteen of 13 cases of clinical Meniere's syndrome were found to have endolymphatic hydrops not attributable to other causes. However, some patients with idiopathic endolymphatic hydrops did not exhibit clinical Meniere's syndrome as revealed in their medical records. These results challenge the dogma that endolymphatic hydrops per se generates the symptoms of Meniere's syndrome.

Radiographic diagnosis, surgical treatment, and long-term follow-up of cholesterol granulomas of the petrous apex.

Cholesterol granuloma is an unusual lesion of the petrous apex. Accurate preoperative differentiation of the various lesions of the petrous apex by computed tomography scanning only has been difficult. We reviewed the clinical findings, computed tomography and magnetic resonance imaging scans, surgical approaches, and long-term follow-up in 10 patients with cholesterol granuloma of the petrous apex who were seen between 1971 and 1988. Headache and deficits of the 5th, 6th, 7th, and 8th cranial nerves were common presenting symptoms. Magnetic resonance imaging with special imaging techniques was accurate in diagnosing cholesterol granuloma in four patients preoperatively and three patients prior to revision surgery. The optimal surgical approach was chosen on the basis of clinical and radiographic findings and included the transsphenoidal, infralabyrinthine, transcochlear, and suboccipital routes. Our review reveals that magnetic resonance imaging is more specific than computed tomography in establishing a preoperative diagnosis and is also the technique of choice in follow-up. The long-term results are discussed.