Vascular tumors (vascular malformations and hemangiomas) of the temporal bone are uncommon, and guidelines for their management have not been published. In an effort to develop an approach to their management, the present study examined the pathological, clinical, and surgical experience with ten of these lesions treated at the Otologic Medical Group, Inc., and St. Vincent Medical Center in Los Angeles from 1960 to 1980. Intratemporal vascular tumors occurred most frequently at two sites, the internal auditory canal and the geniculate ganglion. Histological features and clinical behavior did not correlate. Both vascular malformations and hemangiomata invaded the facial nerve. Surgical excision in these cases required severence and repair of the involved facial nerve. Complete surgical excision is the treatment of choice of vascular lesions of the temporal bone.
This study addresses the question, what difference in hearing between ears puts a patient at sufficient risk of acoustic tumor to warrant further diagnostic tests? The subjects were 210 patients with surgically confirmed unilateral acoustic tumors and a control group comprised of 112 patients referred for audiometry. Hearing thresholds were determined at octave intervals from 250 Hz to 8 kHz. The threshold in the nonsuspect ear was subtracted from the threshold in the suspect ear. The rank order in effectiveness for threshold difference was: 2 kHz, 4 kHz, 1 kHz, 8 kHz, 500 Hz, and 250 Hz. We found that the most effective diagnostic strategy was to refer patients for magnetic resonance imaging if their average threshold difference at 1 to 8 kHz was 20 dB or greater and refer patients for auditory brainstem response testing if their average threshold was 5 to 20 dB.
Comparing 2 pistons designated 0.6 mm in diameter, the Teflon piston produced better hearing results than the titanium device. However, actual piston diameter differed between devices that contributed to the superior results with the larger Teflon piston. In addition, the titanium piston performed better with a small stapes fenestra diameter that suggests an advantage for titanium over Teflon in certain conditions. The clip design was problematic for a few patients.
This study presents the operative results of surgeons with experience in both the translabyrinthine and suboccipital approaches to acoustic tumor removal for the purpose of resolving some of the controversy among centers favoring one approach over the other. The subjects were 171 patients with acoustic tumors who were treated at Virginia Mason Clinic from 1975 to 1986. The translabyrinthine approach was used in 64% of cases, the suboccipital approach in 35%, and the middle fossa approach in 1%. There were minor differences in morbidity and mortality between approaches. These data did not favor one approach over another. In an exploratory analysis, we found that the morbidity with a planned two-stage translabyrinthine-suboccipital removal was greater than the morbidity with a one-stage removal.
Surgical team accounted for more variability in hearing and facial nerve outcome than did approach. Retrosigmoid approach yielded significantly better facial nerve outcome. The trend toward better hearing outcome with the middle fossa approach may never achieve statistical significance across institutions because of high variability among surgical teams and small numbers of teams reporting results.
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