H. Ric Harnsberger

Intralabyrinthine schwannomas: diagnosis, management, and a new classification system.

Objective: To outline the diagnosis and management of intralabyrinthine schwannomas and to propose a new classification system to further define them. Study Design: Retrospective case review. Setting: Tertiary referral center at a university hospital. Patients: Twenty-eight patients seen at the institution with intralabyrinthine schwannomas between 1996 and 2002 were included in the study. Interventions: Diagnosis was made with magnetic resonance imaging in all but one case. Our ability to detect these tumors has been greatly enhanced by the introduction of high-resolution T2-weighted magnetic resonance imaging. Treatment options were observation with serial magnetic resonance imaging versus complete surgical removal via a translabyrinthine or transotic approach. Surgery was indicated for dizziness caused by the tumor or extralabyrinthine growth. Main Outcome Measures: Clinical features, audiology, radiology, and management outcomes were evaluated. Results: Eight patients have undergone successful surgery with removal of their tumors and resolution of symptoms. One patient chose to have stereotactic radiotherapy. Of the 20 patients who were managed with observation and serial magnetic resonance imaging, only 1 has shown significant growth requiring surgical removal. Conclusion: Intralabyrinthine schwannomas are uncommon tumors that mimic the clinical features of many other neurotologic conditions. A high index of suspicion and precise imaging are often required to detect these tumors. Surgical treatment is indicated for specific indications and will be needed in the minority of patients with this disorder. The classification system that we propose is helpful in both the diagnosis and the management of these tumors.

Advanced techniques in magnetic resonance imaging in the evaluation of the large endolymphatic duct and sac syndrome.

The purpose of this report is to compare temporal bone computed tomography (CT) to high‐resolution magnetic resonance (MR) imaging using a novel thin‐section fast spin echo (FSE) pulse sequence in identifying and characterizing patients with large vestibular aqueduct syndrome. Sixteen patients with sensorineural hearing loss and a CT diagnosis of large vestibular aqueduct(s) underwent high‐resolution fast spin echo magnetic resonance imaging with dual, 3‐in phased array receiver coils centered over the external auditory canals. Magnetic resonance imaging parameters included axial and oblique sagittal fast spin echo with an effective slice thickness of 1 mm contiguous. Thirty‐eight patients with 76 normal inner ears who underwent MR imaging using this technique had their endolymphatic duct measured.

Sinus Histiocytosis with Massive Lymphadenopathy (Rosai-Dorfman Disease): Imaging Manifestations in the Head and Neck

OBJECTIVE We present the largest case series in the English-language imaging literature, emphasizing the variety of presentations of Rosai-Dorfman disease in the head and neck. CONCLUSION Rosai-Dorfman disease is a rare disorder with multiple sites of involvement in the head and neck.

Fast spin echo magnetic resonance imaging: Clinical application in screening for acoustic neuroma

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.

Meningioma of the Jugular Foramen: Glomus Jugulare Mimic and Surgical Challenge

Objectives Meningiomas involving the jugular foramen are rare lesions, with approximately 34 cases reported in the English literature. Clinically, these tumors mimic the more common glomus jugulare tumor. After surgical resection, meningiomas have worse cranial nerve outcomes and higher recurrence rates than glomus tumors. There is controversy regarding the selection of surgical approach, particularly with regard to management of the facial nerve. A reliable means of accurate preoperative diagnosis would help surgical planning and patient counseling.

The Impact of Screening Sinus CT on the Planning of Functional Endoscopic Sinus Surgery

The clinical and radiologic records of 500 sequential patients who underwent screening sinus CT as a prelude to possible functional endoscopic sinus surgery (FESS) were reviewed in order to answer three clinical-radiologic questions: (1) Can distinct radiologic patterns of inflammatory disease be identified on screening sinus CT (SSCT)? (2) If so, what are these radiologic patterns? (3) How do the findings seen on SSCT influence the endoscopic surgical plan? Five basic radiologic patterns of sinonasal inflammatory disease were identified among the 500-member patient population. These were based on known patterns of mucociliary drainage correlated with obstructive patterns observed on the CT scans. These radiologic batterns included: (1) Infundibular (129 of 500 or 26%), (2) ostiomeatal unit (126 of 500 or 25%), (3) sphenoethmoidal recess (32 of 500 or 6%), (4) sinonasal polyposis (49 of 500 or 10%), and (5) sporadia (unclassifiable) (121 of 500 or 24%) patterns. Normal SSCT was seen in 133 of the 500 patients (27%). Although the ostiomeatal unit is the central feature in sinonasal inflammatory disease, obstruction of the infundibulum alone or of the sphenoethmoidal recess can cause unique inflammatory patterns of disease that require tailored FESS. The identification of sinonasal polyposis raises a different set of FESS considerations. The sporadic pattern of inflammatory disease, when identified, creates unique FESS challenges, depending on the specific sinus or sinuses involved. Assignment of these patterns to the individual case also assists in patient management by grouping patients into nonsurgical (normal CT), routine (infundibular, ostiomeatal unit, and most sporadic patterns) and complex (sinonasal polyposis and sphenoethmoidal recess) surgical groups.

Ultra high resolution nonenhanced fast spin echo magnetic resonance imaging: Cost-effective screening for acoustic neuroma in patients with sudden sensorineural hearing loss ☆ ☆☆ ★

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.

Apparent cochlear nerve aplasia: to implant or not to implant?

Objective: To describe the imaging findings and clinical outcomes of children with apparent cochlear nerve aplasia undergoing cochlear implantation. Study Design: Retrospective case review. Setting: Tertiary care center. Patients: Three patients with imaging findings consistent with absent cochlear nerve canal on diagnostic imaging and questionable audiometric responses on testing who underwent promontory stimulation and subsequent cochlear implantation. Intervention(s): Magnetic resonance imaging and computed tomography, audiologic assessment, and cochlear implantation. Main Outcome Measure(s): Audiologic performance after cochlear implantation. Results: Three patients were identified to have hearing loss on newborn hearing screening and underwent auditory brainstem response testing revealing absent brainstem responses. ASSR testing was inconclusive when performed. Imaging in all cases identified 1 ear with a small internal auditory canal with 2 nerves present, one of which seems to enter the vestibule in each case and the other is assumed to be the functioning facial nerve. There was a bony plate present over the entrance to the cochlea in 2 of the 3 patients. Over time, 2 of the families reported responses to auditory stimuli with amplification. Promontory stimulation testing showed reproducible responses to electrical stimuli in the ears in question. After cochlear implantation, all 3 patients have shown responses to auditory stimuli. Conclusion: The absence of a visible cochlear nerve or cochlear nerve canal on radiologic imaging does not preclude auditory innervation of the cochlea. Cochlear implantation can be a viable option for patients with apparent cochlear nerve aplasia who have undergone appropriate testing. Electronically evoked auditory brainstem response is critical in the evaluation of this patient group.

Surgical exposure of the petrous internal carotid artery: Practical application for skull base surgery

When exposing the horizontal petrous carotid artery in preparation for intrapetrous carotid by‐pass, the surgeon has no definite landmarks to localize the perimeter of the cochlea. The results of this study provide a practical, consistent, and safe method to maximize carotid artery exposure while minimizing cochlear injury. We measured the carotid‐cochlea distance (mean, 4.3 mm) and the carotid‐cochlear angle (mean, 10.8°) in 33 temporal bones in which the extended middle fossa approach had been performed. We correlated this distance to the width of a Sheehy weapon knife, which can be easily measured intraoperatively. Twenty‐five temporal bones were imaged prior to surgical exposure using a new computed tomography (CT) protocol that can be used for preoperative assessment of the carotid‐cochlear anatomy. The carotid‐cochlea distance and carotid‐cochlear angle measured on CT are compared with postsurgical measurements.

Congenital cholesteatoma of the mastoid temporal bone.

Objective: Congenital mastoid cholesteatomas are rare lesions of the temporal bone. The clinical presentation of these lesions is variable, making them difficult to identify preoperatively. We evaluated our series of mastoid congenital cholesteatomas (CCs) in an effort to better define the clinical presentation, imaging characteristics, and surgical challenges specific to this lesion.