Optokinetic nystagmus (OKN) testing is one method to determine central vestibular dysfunction. OKN may be elicited by partial visual field stimulation with a light bar (OKN‐ENG) or by full visual field stimulation with rotating stripes in a rotational chair test booth (OKN‐RVT). OKN‐ENG and OKN‐RVT were elicited in 36 healthy subjects and 48 patients with known peripheral or central vestibular disorders. Abnormal test results suggested central pathology in 29 of 36 healthy subjects with OKN‐ENG versus 1 of 36 with OKN‐RVT. Twenty‐eight of 33 patients with peripheral pathology demonstrated abnormal OKN‐ENG findings, whereas 4 of 33 had abnormal OKN‐RVT results. Thirteen of 15 patients with central vestibular disorders had abnormal OKN‐ENG, whereas 7 of 15 had abnormal OKN‐RVT. Sensitivity and specificity of OKN‐ENG were 86.7% and 17.4% versus 46.7% and 92.7%, respectively, for OKN‐RVT. These findings were statistically significant ( P < 0.00001). OKN elicited by full visual field stimulation (OKN‐RVT) is a more accurate indicator of central disease than OKN elicited by partial visual field stimulation (OKN‐ENG). The use of OKN‐ENG to identify central vestibular dysfunction is questionable.
An understanding of the complex anatomic relationships within and around the jugular foramen has become increasingly important as neurotologic approaches to the skull base continue to evolve. The jugular foramen and its contents are identified as often to aid in access to other regions of the skull base as to resect lesions that directly involve the area. This review of the anatomy of the contents of the jugular foramen and the surrounding structures via a lateral skull base approach describes the steps necessary to expose the region as well as systematically identifies the contents of the jugular foramen in a manner that resembles actual surgical exposure.
Detailed anatomic analysis of the human temporal bone has been made possible by correlating high-resolution computed tomography (CT) with gross anatomic sections. Serial CT scans of isolated temporal bones were obtained in the transaxial (horizontal), coronal, and sagittal planes at 1.5-mm intervals. The temporal bone was sectioned at 2.0-mm intervals in planes parallel to the CT scans. Based on a correlation of these sections, the facial nerve canal was divided into four segments and the planes in which each is best observed are described and illustrated. The first segment in the internal auditory canal is best visualized in the sagittal plane, the labyrinthine segment and geniculate ganglion in the coronal and transaxial planes, the tympanic portion in the sagittal plane, the genu, between the tympanic and mastoid portion, in the sagittal plane, and the mastoid portion and the stylomastoid foramen in the coronal and sagittal planes.
Patients with localized damage to the taste system often experience no subjective change in real-world taste experience. In an effort to understand this, eight patients who recently underwent acoustic neuroma removal were evaluated for taste loss. Localized taste testing showed that taste intensities decreased in the distribution of cranial nerve VII ipsilateral to tumor removal as expected, but asymmetries occurred for IX. Intensities were greater on the side contralateral to the tumor removal. In addition, palatal taste, also thought to be mediated by VII, was not totally abolished. It is concluded that cranial nerve IX is normally inhibited by cranial nerve VII in the taste network. When VII is damaged, this inhibition is abolished. This release of inhibition serves as a compensation mechanism that preserves normal taste experience.
Objective The objective of this study is to evaluate the efficacy and outcomes of using a transmastoid approach with hydroxyapatite cement to repair lateral skull base cerebrospinal fluid (CSF) leaks. Study Design Retrospective cohort study. Setting Tertiary-level care hospital. Patients Surgical patients 18 years or older between 2013 and 2022 with spontaneous CSF leak. Interventions Trans-mastoid approach for skull base repair using hydroxyapatite cement. Main Outcome Measures Failure rate of repair; location and size of defect, patient demographic factors. Results Of the 60 total defects (55 patients, 5 bilateral repairs) that underwent CSF leak repair using hydroxyapatite cement, the success rate was 91.66% (55 successful repairs). The average defect size in unsuccessful repairs was 1.15 cm compared with 0.71 cm for successful repairs. In addition, 80% (4/5) of the failed repairs were in the tegmen tympani region. Higher failure rate was noted in women (3/5) and in former smokers (4/5). Average time to recurrent symptoms was 1.75 years in the failed repair cohort. Of the patients with failed repairs, 4/5 were prescribed acetazolamide before their second procedure with successful second repair. In addition, five patients experienced postoperative headaches, three (5.4%) of whom required placement of VP shunts to relieve increased intracranial pressure. Two patients (3.6%) had complications of either infection or hearing loss. Conclusions Transmastoid approach utilizing hydroxyapatite is a successful approach for CSF leak repair, with a low complication and failure rate. Women, prior smoking history, and larger defects in the tegmen tympani region may need alternative materials or approach for repair. Long follow-up is warranted as recurrence of symptoms might be delayed. In cases of benign intracranial hypertension, adjuvant treatment with either acetazolamide or VP shunt placement may prevent failures.
Over the past several years the indications for adenoidectomy have become increasingly controversial. Attempts to justify the operation in recurrent otitis media by correlating cultures of the nasopharynx with cultures of middle ear fluid have been inconclusive. Using quantitative bacteriologic techniques, we have studied the levels of aerobic and anaerobic bacteria per gram of tissue in adenoids removed from 48 patients. In seven patients, adenoidectomy was performed for nasal obstruction alone, in 17 patients for chronic serous otitis media, and in 24 patients for recurrent suppurative and serous otitis media. Using the criterion that greater than 10(5) organisms/gm of tissue constitutes infection, we found that 83% (20) of patients in the third group had infected adenoids, as opposed to only 15% (4) in the first and second group combined. Adenoid size measured radiographically did not correlate with the presence of infection. Adenoid size measured radiographically did not correlate with the presence of infection. When recurrent suppurative and serous otitis media are unresponsive to medical therapy including antibiotics and decongestants, adenoidectomy should be considered in addition to myringotomy and ventilation tubes.
