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Objective: To define the clinical presentation, treatment options, and outcomes for a subset of meningiomas of the posterior fossa skull base that arise from the posterior petrous face between the region of the porus acousticus and the sigmoid sinus., Study Design and Setting: A retrospective chart review from a large skull base surgery practice at a tertiary care institution., Results: This cohort of patients presented with minimal symptoms, yet large tumors, averaging 3.8 cms and causing significant cerebellar compression. Retrosigmoid craniotomies afforded excellent exposure., Conclusion and Significance: Patients with large tumors emanating from the posterior fossa aspect of the temporal bone should be evaluated on the basis of their site of origin. Patients with tumors emanating from the anterior or ventral portion of the temporal bone have greater symptoms and greater operative complications than those emanating from the posterior petrous face, between the porus acousticus and sigmoid sinus.

We reviewed our experience with 100 children admitted to Children's Hospital of Pittsburgh between 1980 and 1995 with an intratemporal complication of acute otitis media. Seventy-two patients were treated for acute mastoiditis. Of these 72 children, 54 (75.0%) were treated conservatively with broad-spectrum intravenous antibiotics and myringotomy. Eighteen (25.0%) required mastoidectomy for treatment of a subperiosteal or Bezold's abscess or cholesteatoma, or because of poor response to conservative therapy. Twenty-two children presented with facial paralysis, complete in 5 (22.7%) and incomplete in 17 (77.3%). Eighteen (81.8%) were treated conservatively, but four required mastoid surgery. Nineteen patients had adequate follow-up; of these, 15 recovered normal facial function but 4 were left with partial paralysis. Three patients presented with serous labyrinthitis and recovered completely with conservative therapy. Of the two patients who presented with suppurative labyrinthitis, one was treated conservatively, but the other required tympanomastoidectomy with cochleotomy; both patients had permanent, profound sensorineural hearing loss in the affected ear. Four patients presented with acute petrositis, and in all four it resolved with mastoidectomy. In the antibiotic era, intratemporal complications of acute otitis media still occur in otherwise healthy children, often after inadequate treatment of acute otitis media.

The financial burden for the evaluation of patients for acoustic neuroma in an otolaryngology practice is substantial. Patients with sudden sensorineural hearing loss represent a portion of that population seen with unilateral, asymmetric auditory symptoms who require investigation for acoustic neuroma. For these patients, gadolinium-enhanced magnetic resonance imaging is the diagnostic gold standard. Auditory brain stem response testing has been used in the past as a screening test for acoustic neuroma, but its apparent sensitivity has fallen as the ability to image smaller acoustic neuromas has improved. Fast spin echo magnetic resonance imaging techniques without gadolinium have been shown to be as effective in the detection of acoustic neuroma as contrast-enhanced magnetic resonance imaging. Limited nonenhanced fast spin echo magnetic resonance imaging now provides an inexpensive alternative for high-resolution imaging of the internal auditory canal and cerebellopontine angle. Fast spin echo magnetic resonance imaging can now be done at a cost approximating auditory brain stem response testing while providing the anatomic information of contrast-enhanced magnetic resonance imaging. Cost analysis was done in the cases of 58 patients with sudden sensorineural hearing loss by comparing the costs for routine workup and screening of acoustic neuroma with the cost of fast spin echo magnetic resonance imaging with the use of screening protocols based on literature review. The potential cost savings of evaluating patients with sudden sensorineural hearing loss with fast spin echo magnetic resonance imaging for acoustic neuroma was substantial, with a 54% reduction in screening costs. In an era of medical economic scrutiny, fast spin echo magnetic resonance imaging has become the most cost-effective method to screen suspected cases of acoustic tumors at our institution by improving existing technology while reducing the cost of providing that technology and eliminating charges for impedance audiometry, auditory brain stem response testing, and contrast-enhanced magnetic resonance imaging.

Otocephaly is a lethal malformation of the first and second branchial arches, which consists of ventromedial displacement of the external ear structures (synotia), mandibular aplasia (agnathia), absence of the tongue (aglossia), and microstomia. We present the first complete description of the temporal bone findings in a case of otocephalus. A three-dimensional computer-assisted reconstruction of the right temporal bone was performed, allowing a unique graphic analysis. An extremely low-lying middle fossa tegmen was noted with malrotation of the middle ear structures. Severe ossicular malformations were also found. An anomalous course of the internal carotid artery was noted with indentation of the basal turn of the cochlea. All three layers of the otic capsule were incompletely developed. Cochlear bony dehiscences were noted. These findings are consistent with early arrest of fetal development and malrotation caused by lack of growth pressure from the mandibular arch. Implications of these findings in the embryologic development of the ear are discussed.

The advent of magnetic resonance imaging has greatly improved our ability to diagnose acoustic tumors, but it is a relatively expensive imaging modality. In the present climate of medical cost restraints, methods that reduce costs but maintain quality are extremely desirable. We report a new magnetic resonance imaging technique that uses fast spin echo without gadolinium. It provides ultrahigh-resolution images of the internal auditory canal and cerebellopontine angle. The sensitivity of this technique for the detection of acoustic tumors is equivalent to conventional gadolinium-enhanced magnetic resonance imaging, but the global cost is comparable with that of brain stem audiometry. In our practice fast spin echo magnetic resonance imaging has replaced brain stem audiometry as a screening modality to evaluate most acoustic tumor suspects. Also, the intricate detail of the internal auditory canal anatomy provided by this technique is useful in planning surgical removal of acoustic tumors.

We report the presence of a schwannoma within a neurofibroma of the intratemporal facial nerve. This neurofibroma recurred 39 years after its first excision in the parotid gland. Although some believe that schwannomas and neurofibromas represent the same entity, these tumors present distinctive histopathologic and clinical characteristics, which are discussed. The extreme rarity of a schwannoma developing within a neurofibroma is underlined. This is the first report of such an association occurring within a cranial nerve.

Transitory evoked otoacoustic emissions are normal phenomena observed in most persons with hearing levels greater than 35 dB. Further, masking of the contralateral ear produces amplitude reductions in the transitory evoked otoacoustic emissions. We have undertaken a study of transitory evoked otoacoustic emissions in 20 patients with acoustic neuroma. All patients were assessed for transitory evoked otoacoustic emissions bilaterally, with and without contralateral masking with white band noise at 40, 50, and 60 dB. We found that transitory evoked otoacoustic emissions were present in 30% of ears with tumor and that the presence of transitory evoked otoacoustic emissions is associated with improved preoperative hearing levels, but that tumor size is not associated with the presence or absence of transitory evoked otoacoustic emissions. The amplitude of transitory evoked otoacoustic emissions from ears with tumor, when present, is decreased when compared with normal ears of normal patients. Further, with contralateral masking little of the amplitude reduction observed in normal patients is observed in the ears with acoustic neuroma. However, with masking of the contralateral ear, the ear without tumor demonstrated significantly greater amplitude reductions than normal ears from normal patients (p = 0.0006). Pertinent anatomy and possible explanations for these findings are discussed.

Preoperative and postoperative facial nerve and auditory function were reviewed retrospectively in 13 cases of cerebellopontine angle meningiomas. According to their location within the posterior fossa and with special reference to the internal auditory canal, they were classified into a premeatal and a retromeatal group. All the tumors were removed by an otoneurosurgical team by use of a retrosigmoid approach. Postoperative results (1 year after operation) were compared within the two groups with respect to preservation of hearing (normal hearing in 31% and preservation of preoperative hearing in 69% of the cases) and facial nerve function (no or mild postoperative impairment in 69% of the cases). Both preoperative and postoperative impairment of facial nerve and auditory function prevailed in the premeatal group. For preservation of vital vascular and central nervous structures, subtotal resection with consecutive fractionated radiation therapy had to be performed in 30% of the cases. Our results provide substantial evidence that in cerebellopontine angle meningiomas a precise preoperative study of tumor location will assist in improving individual operative strategy and thus postoperative functional results.

Giant cell tumors of the temporal bone are very rare lesions. They should be differentiated from other giant cell lesions of bone, mainly reparative granulomas. A case with a very huge giant cell tumor of the temporal bone extending to the infratemporal fossa, temporomandibular joint, and greater wing of the sphenoid has been presented. Because of their tendency for recurrence, total removal is the treatment of choice for these tumors and was accomplished through the infratemporal fossa approach type B. A follow-up of 2 years and 9 months revealed no evidence of tumor recurrence.

The use of MRI for the evaluation of lesions in the internal auditory canal presents a potential pitfall in the diagnosis of bony lesions of the IAC, because bone is poorly visualized with this method of imaging. The presence of marrow in an osteoma might aid in its detection, since fat in the marrow has a bright signal intensity of T1-weighted imaging. Computed tomography remains the imaging modality of choice for bony lesions of the temporal bone. We demonstrate a case of IAC osteoma in which surgical removal resulted in improvement of symptoms. The gross and microscopic appearance of the IAC osteoma in this case is similar to the characteristic findings of osteomas of the EAC. This suggests that the criteria applied to osteomas and exostoses of the EAC may also be used to differentiate bony lesions of the IAC.

Circumferential growth of parotid neoplasms may involve the external auditory meatus posteriorly, the floor of the middle cranial fossa superiorly, and the neurovascular structures of the jugular foramen medially. Inadequate tumor resection in these anatomically complex regions will result in local disease recurrence at the lateral skull base. A subtotal petrosectomy approach has been combined with a standard total parotidectomy in the management of 27 patients with aggressive parotid tumors. Twenty-two patients had malignant lesions and 10 individuals had recurrent disease. The resultant conductive hearing loss is outweighed by the following advantages of this technique: (1) the ability to obtain tumor-free bony margins, (2) proximal intratemporal facial nerve identification, (3) vascular control of the jugular bulb and petrous carotid artery, and (4) the dissection and protection of cranial nerves IX through XII. Our series of 27 patients will be detailed with an emphasis on surgical technique and overall patient results.

Lipoma of the internal auditory canal is a rare tumor. Clinically, it presents like an acoustic tumor. The diagnosis can be made with the use of a magnetic resonance imaging showing a high intensity on T1- and low intensity on T2-weighted image with no enhancement. Pathologically, this is a soft, smooth, yellow tumor with some fat in it that can resemble grossly any acoustic tumor. The lipoma is intermixed with the eighth nerve and can be adherent to adjacent structures. The growth of a lipoma can be slower than an acoustic tumor. A patient diagnosed with lipoma of the internal auditory canal can often have quite good hearing. As an alternative to surgical removal, another therapeutic option is to watch the growth of the lipoma with periodic magnetic resonance imaging, probably on a yearly basis initially.

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.

Three patients with high-intensity MR signals from one petrous apex, but nonpathologic fine-cut computed tomography are reported. In two of the three patients, normal bone marrow within the petrous apex on one side is believed to have generated the high-intensity signal. In one of the three patients, the etiology of the MR image remains obscure, but may represent the earliest stages of petrous cholesterol granuloma or mucocele. We have reviewed 500 head CT scans performed for non-otologic reasons, in an attempt to establish the frequency of this finding. The literature on MR and CT imaging of the petrous apex and asymmetric pneumatization of the petrous apex is reviewed.