Calcium sulfate bone void filler: a review and a look ahead.

Bone grafting to augment skeletal healing has become one of the most common techniques in surgical practice. However, the morbidity and limited availability associated with autografts, and the potential for disease transmission, immunogenic response, and variable quality associated with allografts, have engendered a plethora of alternative materials. Such alternatives range from the simple, such as calcium sulfate and calcium phosphate materials, to the complex that contain allograft extracts, bone morphogenetic proteins, or other agents. Calcium sulfate has the distinction of being the alternative that is both one of the simplest as well as that which has the longest clinical history as a synthetic bone graft material--spanning more than 100 years. This article reviews the structure and function of calcium sulfate as a synthetic bone void filler and speculates on its future surgical role. It is anticipated that this foundation will also help assist in the understanding of how other bone graft alternatives may operate.

Hydrogen sulfide and the probabilities of 'inhalation' through a tympanic membrane defect.

We conclude that workers with tympanic membrane defects (perforated eardrums) should not be excluded from working in atmospheres containing concentrations of hydrogen sulfide (H2S). Several existing requirements and recommendations exclude workers with perforated eardrums from working in or around H2S. Such protective measures stem from the belief that H2S can enter the body through the perforation in sufficient measure to compromise the wearer's respiratory protection. However, based on calculations of anticipated leakage of H2S for a variety of eustachian tube conditions and in the absence of either medical literature or personal reports documenting H2S poisoning due to eardrum perforation, the recommendation for excluding workers with such a condition from working in or around H2S is not supported. The anatomy, physiology, and pathology of the eustachian tube are discussed, including the effects such devices as tympanomaxillary shunts might have on contaminant leakage. The National Institute for Occupational Safety and Health (NIOSH) criteria for respirator tests and sources of respirator leakage are examined and NIOSH recommendations for respiratory protection against H2S are outlined.