A comparison of median hearing thresholds from U.S. Navy and U.S. Army audiometric data bases.

This study examined 1984 monitoring audiometric data from U.S. Navy (military and civilian) employees whose workplace required a mandatory hearing conservation program. Median hearing thresholds were compared in U.S. Navy employees, U.S. Army employees also monitored by a hearing conservation program, and a standard population from the First National Health and Nutrition Survey. Age group and frequency-specific comparisons were included. Results at 4 kHz and 6 kHz demonstrated higher median thresholds in the Navy populations that were significantly higher by clinical and statistical criteria. Possible reasons for the differences are given.

Experimental evaluation of a new implant material in frontal sinus obliteration: a preliminary report.

Frontal osteoplasty with exogenous material has been uniformly unsuccessful both experimentally and clinically. Our experiment was designed to test the long-term behavior of a new poly (tetrafluoroethylene)-carbon fiber implant material (Proplast) in a canine frontal sinus model. Varying conditions such as removal of the sinus mucoperiosteum, closure of the nasofrontal ducts, exposure of dura mater, and cerebrospinal fluid leaks were studied at intervals up to one year. Proplast was 100% successful in obliteration of the canine frontal sinus. The ultraporous nature allowed rapid vascularization, collagen ingrowth, and new bone formation, and led to stabilization rather than sequestration. Frontal obliteration with Proplast may be clinically superior to osteoplasty with any other presently available exogenous material or with osteoneogenesis alone, and may even obviate the few complications encountered with adipose implants. Only longer range experimental and clinical evaluation will provide the answer.