Mitchell S. Marion

Conservative management of acoustic neuroma: an outcome study.

OBJECTIVE This study analyzed selection criteria, clinical outcome, and tumor growth rates in patients with acoustic neuromas in whom the initial management strategy was observation. METHODS A retrospective review of patients with conservatively managed unilateral acoustic neuromas was conducted. Minimum follow-up was 6 months. Patients with neurofibromatosis Type II were excluded. Differences in tumor growth rates were analyzed by use of the Wilcoxon rank sum test. RESULTS Sixty-eight patients (31 men and 37 women) with a mean age of 67.1 years were followed for an average of 3.4 years after diagnosis. The reasons for a trial of observation included advanced age (55%), patient preference (21%), minimal symptoms (9%), poor general medical condition (7%), asymptomatic tumor (4%), and tumor in the only hearing ear (4%). Fifty-eight patients (85%) were successfully managed with observation alone. Ten patients (15%) ultimately required treatment (nine received microsurgical treatment and one patient underwent radiosurgical intervention) at a mean time interval of 4.0 years after diagnosis. Forty-eight tumors (71%) showed no growth and 20 (29%) enlarged during the study period. The mean tumor growth rate at the 1-year follow-up was significantly higher in the group requiring treatment (3.0 mm) than in the group not requiring treatment (0.36 mm) (P < 0.0001). Thus, the tumor growth rate at the 1-year follow-up was a strong predictor of the eventual need for treatment. CONCLUSION Observation is a reasonable management strategy in carefully selected patients with acoustic neuromas. Diligent follow-up with serial magnetic resonance imaging is recommended, because some tumors will enlarge to the point at which active treatment is required.

Labyrinthitis Ossificans: Histopathologic Consideration for Cochlear Implantation

Labyrinthitis ossificans may be a hindrance to cochlear implantation by making electrode insertion difficult. We performed a histopathologic study of 24 temporal bones with labyrinthitis ossificans from multiple causes. The organ of Corti was graphically reconstructed and the degree of obstruction was estimated for each millimeter of the cochlea. Correlations were calculated between the degree of new bone formation and the cause, patients age and sex, and time from the original temporal bone insult. Our results demonstrate that complete cochlear ossification is rare. The scala tympani in the basal turn of the cochlea is the most frequent area of ossification, regardless of the cause of the labyrinthitis ossificans. Meningogenic labyrinthitis, usually a childhood disease, was associated with the greatest amount of ossification. When ossification resulted from tympanogenic labyrinthitis, the scala tympani was completely ossified near the round window niche in all temporal bones. Neo-ossification of the basal turn associated with otosclerosis was limited to the proximal 6 mm of the scala tympani in all cases. Three temporal bones had a patent round window niche and basal turn, but significant apical and middle-turn ossification. Peripheral sensorineural elements were severely degenerated in the region of the ossification in all specimens, and spiral ganglion cell counts were decreased.

Histopathologic evaluation of adipose autografts in a rabbit ear model.

Injection of autologous adipose tissue removed via liposuction has been used clinically for facial contouring, the aging face, furrows, facial atrophy, acne scars, nasolabial folds, chin, and various other surgical defects. Survival rates for autografts of fat have been quoted anywhere from 30% to 80%. Our study uses a reproducible rabbit animal model for autotransplantation of adipose tissue and examines the histopathologic changes that occur to the graft over time. Autogenous subcutaneous fat was removed from a dorsal scapular donor site, treated to stimulate cannula damage as in liposuction, then reinjected at the base of the ear. Histologic examination of the grafts were made at 5, 10, 15, 20, 40, and 100 days after transplantation. Hematoxylin-eosin sections were graded on degree of fibrosis present (0 to 4+), viable fat (1 to 10), degree of inflammation (0 to 4+), and neovascularization (+ or -). Viability of fat decreased from 8.5 to 10 at 5 days to 2 viability at 40 days. Acute inflammation peaked at 10 days, followed by the chronic inflammatory response with macrophages and multinucleated giant cells scavenging the dying fat graft. Neovascularization began at 5 days, peaked at 10 days, and remained constant thereafter only at the edge of the graft. Microcysts appeared at 15 days and increased in number in proportion to the decrease in viable fat. In summary, the temporal histologic events are progressive fibrosis; decreased amount of viable fat; inflammation beginning with a neutrophilic response, later a macrophage and giant cell response; and neovascularization at the periphery of the graft insufficient to maintain graft viability. In our animal model, autografts of fat appear to have limited long-term viability and are replaced by fibrous tissue. This may have clinical implications in autografting of fat in facial plastic and reconstructive surgery.

Aphysiologic performance on dynamic posturography

The remarkable ability of the body to maintain balance is the result of central nervous system integration of sophisticated inputs from the vestibular, visual, and somatosensory systems. Strategies by patients with balance dysfunction are aphysiologic when their performance is relatively better on more difficult conditions of sensory conflict than on easier ones. Twenty-two aphysiologic patterns on computerized dynamic posturography were compared with age-matched normal and vestibular patterns. The aphysiologic group performed significantly better than the patients in the vestibular dysfunction group on the most difficult subtests of computerized dynamic posturography, conditions 5 and 6, yet significantly poorer on the easier subtests, conditions 1 through 4. In addition, patients in the aphysiologic group tended to show greater intertrial variability compared with patients in both normal and vestibular system dysfunction groups. A stepwise linear discriminant analysis was used to determine a set of conditions that had significant value in discriminating between the three patient groups. Case studies are presented to further illustrate the clinical usefulness of computerized dynamic posturography testing in the evaluation of patients suspected of having a functional component to their on-feet balance problems.

Three-dimensional reconstruction of the temporal bone.

Study of the complex anatomy and pathology of the temporal bone has traditionally used microscopy which permits analysis in only two dimensions. Recent advances in bioimaging technology have permitted visualization and reconstruction of computed tomography images in three dimensions. We have developed a technique that applies this technology in the imaging and reconstruction of human temporal bones. Data taken from serial histologic sections of the temporal bone are entered into a computer. The sections are edited and, through the use of specially developed software, a realistic three‐dimensional reconstruction is produced. The reconstructed image can be rotated along any of three axes, and structures within the temporal bone can be isolated for more detailed analysis. Applications for the study of pathologic conditions of the temporal bone will be discussed.

Persistence of the stapedial artery: a histopathologic study.

Persistence of the stapedial artery is a rare event. Fewer than 30 cases have been reported since the discovery of this artery in 1836. We carried out a histopathologic study on three temporal bones from two patients who had this anomaly, and were able to trace the full course of the artery. In two specimens a large stapedial artery persisted and substituted for the middle meningeal artery. In the third, a small, persistent stapedial artery ended in the arterial plexus surrounding the facial nerve. Persistence is discussed in terms of embryogenesis, developmental theories, histologic findings, and clinical significance. The material suggests that the stapedial artery can persist to varying degrees

Temporal bone fractures: a histopathologic study.

Trauma or injury to the skull, if of sufficient force, may produce a temporal bone fracture. However, terms such as basilar skull fracture, labyrinthine hemorrhage, or labyrinthine concussion are inadequate in that they do not describe the precise histopathologic lesion. We carried out a histopathologic study of the 14 ears in seven patients; all the patients suffered at least one temporal bone fracture. Our objective was to review the histopathologic findings of various fracture lines through the base of the skull and correlate these with the history and clinical findings.

Otosclerosis and sensorineural hearing loss: a histopathologic study.

The precise role and mechanism whereby otosclerosis is associated with sensorineural hearing loss remains unclear. Previous histopathologic reports are inconsistent with regard to the location of the otosclerotic focus, invasion of the otic capsule, and the number of remaining peripheral sensorineural elements. From the combined temporal bone collections of the University of Chicago and the Mayo Clinic, we identified a group of 125 ears from 80 patients, all with confirmed otosclerosis. Six of these ears were associated clinically with sensorineural hearing loss without stapes fixation. The histopathology of the otosclerotic focus was reviewed in terms of its location and depth of invasion. The cochlea and spiral ganglion were reconstructed, and the state of the organ of Corti and the presence or absence of peripheral cochlear nerve fibers were noted. Correlations with ganglion cell counts were made. The present study showed that the pattern of degeneration of peripheral sensory and neural elements in the cases presented is very similar to that found in cases of age-related processes such as presbycusis.

TEMPORAL BONE HISTOPATHOLOGY : RESIDENT'S QUIZ

The patient began to lose his hearing as a young child, having multiple ear infections resulting in bilateral chronic otitis media. After death, the patients temporal bones were harvested, fixed, decalcified, and embedded in celloidin. Preparations consisting of horizontal sections cut at 20 μm were stained with hematoxylin-eosin and reviewed

Metastatic Squamous Cell Carcinoma to the Temporal Bone

A 52-year-old female noticed pressure in her right cheek associated with intermittent pain. Intranasal biopsy showed a squamous cell carcinoma of the right antrum. She underwent a right radical maxillectomy. Unfortunately, the tumor recurred locally 8 years later and further surgery was followed by radiation therapy. Four years later, at the age of 64, the patient noticed hearing loss in the right ear, which progressed to profound deafness. Later, the patient became progressively weaker and was admitted to a nursing home where she deteriorated and died. Pathological evaluation of the temporal bone demonstrated metastatic squamous cell carcinoma of the maxilla to the temporal bone [Fig. 1).