Faculty Bibliography

OBJECTIVE: Factors that play a role in the selection of surgical approach for acoustic neuromas include patient health and age, size of tumor, hearing status, and location of tumor in the internal auditory canal (IAC) and the cerebellopontine angle. Deep extension into the IAC makes hearing preservation extremely difficult when a retrosigmoid craniotomy is used, and the best approach is a middle fossa subtemporal route. Modern gadolinium-enhanced magnetic resonance imaging (MRI) can be inaccurate in identifying the presence of tumor laterally in the IAC. This may affect the selection of a surgical approach. STUDY DESIGN: This study was a retrospective case review. SETTING: Patients were accrued from a tertiary referral otologic practice. PATIENTS: From 1997 through 2000, the authors identified six patients who had undergone acoustic neuroma surgery, had adequate imaging and intraoperative data, and demonstrated a lack of correlation between MRI and intraoperative findings of the lateral IAC. INTERVENTION: The interventions were preoperative MRI of the IAC and surgical resection of an acoustic neuroma. MAIN OUTCOME MEASURE: Comparison of MRI and intraoperative findings of the lateral IAC were the main outcome measures. RESULTS: Six patients demonstrated a lack of correlation between MRI and intraoperative findings of the lateral IAC. CONCLUSIONS: Gadolinium-enhanced T1-weighted MRI findings of the depth of penetration into the lateral aspect of the IAC do not always correlate with intraoperative findings and thus may have implications in the selection of surgical approaches to acoustic neuromas.

OBJECTIVE: The purpose of this study was to examine possible associations between severity of clefting in infants and maxillary growth in children with complete unilateral cleft lip and palate. DESIGN: This was a retrospective study of measurements made on infant maxillary study casts and maxillary cephalometric variables obtained at 5 to 6 years of follow-up. SETTING: The study was performed at the Institute of Reconstructive Plastic Surgery of New York University Medical Center, New York, New York. PATIENTS: Twenty-four consecutive nonsyndromic unilateral complete cleft lip and palate patients treated during the years 1987 to 1994. INTERVENTIONS: All the patients received uniform treatment (i.e., presurgical orthopedics followed by gingivoperiosteoplasty to close the alveolar cleft combined with repair of the lip and nose in a single stage at the age of 3 to 4 months). Closure of the palate was performed at the age of 12 to 14 months. RESULTS: Infant maxillary study cast measurements correlated in a statistically significant manner with maxillary cephalometric measurements at age 5 to 6 years. CONCLUSIONS: The results demonstrate the large variation in the severity of unilateral cleft lip and palate deformity at birth. Patients with large clefts and small arch circumference, arch length, or both demonstrated less favorable maxillary growth than those with small clefts and large arch circumference or arch length at birth

OBJECTIVE: To examine the relationship between histopathology, immunohistochemistry, and clinical behavior in atypical and low-grade malignant vestibular schwannomas. STUDY DESIGN: The study design was a retrospective case review in conjunction with a histopathologic and immunohistochemical proliferation marker study of archival specimens. DATA SOURCES: A tertiary referral center's anatomic pathology and vestibular schwannoma computerized databases. METHODS: The diagnosis of atypical or low-grade malignant vestibular schwannoma was based on the number of mitotic figures present per tumor slide. MIB1 labeling indices were used to compare the proliferative activity of the atypical and low-grade malignant groups with that in an age-matched and size-matched control group. RESULTS: Eight cases of atypical and six cases of low-grade malignant vestibular schwannoma were diagnosed from 1990 to 1998. In the atypical and low-grade malignant groups, respectively, the average patient age was 54.3 years (range, 38-74 yr) and 50 years (range, 38-72 yr), and the average total tumor size was 1.53 cm (range, 0.7-3.5 cm) and 1.55 cm (range, 1.5-2 cm). Two recurrences were identified from the low-grade malignant group, and there was one postoperative House-Brackmann Grade III facial weakness. There were no recurrences or facial palsies in the atypical group. No distant metastasis or aggressive local invasion was observed in either group. MIB1 labeling indices were significantly (p < or = 0.001) higher in the atypical (4.69%) and low-grade malignant (5.23%) groups than in the control group (1.99%). CONCLUSIONS: These findings suggest a tendency for recurrence in proliferative tumors; however, the designation of malignancy should be reconsidered

Malignant lymphoepithelial lesions are rare tumors of the major salivary glands. They most often occur in Asians and Greenland Eskimos and are strongly associated with Epstein-Barr virus infection. We report a case of a malignant lymphoepithelial lesion of the parotid gland that developed in an Italian-American woman whose serology was positive for Epstein-Barr virus antibody. The patient underwent a left total parotidectomy and upper neck dissection, followed by radiation therapy. At the 2-year follow-up, she remained free of disease.

BACKGROUND AND PURPOSE: Only a small percentage of acute-stroke patients receive thrombolytic therapy because of time constraints and the risks associated with thrombolytic therapy. We sought to determine whether xenon-enhanced CT (XeCT) cerebral blood flow (CBF) and/or CT angiography (CTA) in conjunction with CT can distinguish subgroups of acute ischemic stroke victims and thereby better predict the subgroups most likely to benefit and not to benefit from thrombolytic therapy. METHODS: An analysis of 51 patients who had a CT, CTA, and stable XeCT CBF examination within 24 hours of stroke symptom onset was conducted. These initial radiographic studies and National Institutes of Health Stroke Scale score on admission were assessed to determine whether they could predict new infarction on follow-up CT or discharge disposition by use of the Fisher exact test to determine statistical significance. RESULTS: Patients with no infarction on initial CT and normal XeCT CBF had significantly fewer new infarctions and were discharged home more often than those with compromised CBF. The same held true for patients with an open internal carotid artery and middle cerebral artery by CTA and normal CT compared with those with an occluded internal carotid artery and/or middle cerebral artery by CTA. Either was superior to CT and the National Institutes of Health Stroke Scale in prediction of outcome. Both enable the selection of a group of patients not identifiable by CT alone that would do well without being exposed to the risks of thrombolytic therapy. This study included too few patients to statistically assess the role of combining CTA and XeCT CBF information. CONCLUSIONS: The combination of CT, CTA, and Xe/CT CBF does define potentially significant subgroups of patients. The utility of this classification is supported by the observation that CTA and XeCT CBF are superior to CT alone in predicting infarction on follow-up CT and clinical outcome. This information may be useful in selecting patients for acute-stroke treatment

Magnetic relaxation has been used extensively to study and characterize biological tissues. In particular, spin-lattice relaxation in the rotating frame (T(1rho)) of water in protein solutions has been demonstrated to be sensitive to macromolecular weight and composition. However, the nature of the contribution from low frequency processes to water relaxation remains unclear. We have examined this problem by studying the water T(1rho) dispersion in peptide solutions ((14)N- and (15)N-labeled), glycosaminoglycan solutions, and samples of bovine articular cartilage before and after proteoglycan degradation. We find in model systems and tissue that hydrogen exchange from NH and OH groups to water dominates the low frequency water T(1rho) dispersion, in the context of the model used to interpret the relaxation data. Further, low frequency dispersion changes are correlated with loss of proteoglycan from the extra-cellular matrix of articular cartilage. This finding has significance for the noninvasive detection of matrix degradation.

Two of the primary cues used to localize the sources of sounds are interaural level differences (ILDs) and interaural time differences (ITDs). We conducted two experiments to explore how practice affects the human discrimination of values of ILDs and ongoing ITDs presented over headphones. We measured discrimination thresholds of 13 to 32 naive listeners in a variety of conditions during a pretest and again, 2 weeks later, during a posttest. Between those two tests, we trained a subset of listeners 1 h per day for 9 days on a single ILD or ITD condition. Listeners improved on both ILD and ITD discrimination. Improvement was initially rapid for both cue types and appeared to generalize broadly across conditions, indicating conceptual or procedural learning. A subsequent slower-improvement stage, which occurred solely for the ILD cue, only affected conditions with the trained stimulus frequency, suggesting that stimulus processing had fundamentally changed. These different learning patterns indicate that practice affects the attention to, or low-level encoding of, ILDs and ITDs at sites at which the two cue types are processed separately. Thus, these data reveal differences in the effect of practice on ILD and ITD discrimination, and provide insight into the encoding of these two cues to sound-source location in humans

Paragangliomas of the head and neck are derivatives of neural crest cells, comprising part of the diffuse neuroendocrine system. Indeed, paragangliomas encompass a unique subset of tumors of the head and neck. Their biochemistry and physiology are similar to other neuroendocrine tumors unlike tumors based on location. This article discusses their distinct biologic attributes