Biologic response to passive dissolution of titanium craniofacial microplates.

The effect of anodization on passive dissolution of titanium was studied by measuring titanium levels in peritoneal leukocytes and tissues of laboratory animals with titanium plates implanted into the peritoneal cavity. Fifteen Sprague-Dawley rats were assigned randomly to three treatment groups of five animals. One group served as controls, the other two groups had an anodized or an unanodized implant placed in the left paracolic gutter. Peritoneal lavage samples and blood samples, organ tissues and tissue surrounding the implants, were removed for histologic examination and titanium levels. Titanium was not detected in any distant organs or in the peritoneal lavage fluid. The capsular tissues surrounding the implants contained titanium at levels ranging from 2610 to 16786 ng/g for unanodized plates, and 888-5933 ng/g for anodized plates. The titanium levels within the peritoneal leukocytes of animals with unanodized implants were significantly elevated (P = 0.01) over time, as compared with controls. The level of titanium in the peritoneal leukocytes of animals with anodized implants was not significantly elevated when compared with controls. Titanium levels in the trace range, as measured in the capsular tissues, are likely a result of corrosion. Surface treatment of titanium by anodization reduces passive dissolution.

Detection of titanium in human tissues after craniofacial surgery.

Generally, titanium fixation plates are not removed after osteosynthesis, because they have high biocompatability and high corrosion resistance characteristics. Experiments with laboratory animals, and limited studies of analyses of human tissues, have reported evidence of titanium release into local and distant tissues. This study summarizes our results of the analysis of soft tissues for titanium in four patients with titanium microfixation plates. Energy dispersive x-ray analysis, scanning electron microscopy, and electrothermal atomic absorption spectrophotometry were used to detect trace amounts of titanium in surrounding soft tissues. A single metal inclusion was detected by scanning electron microscopy and energy dispersive x-ray analysis in one patient, whereas, electrothermal atomic absorption spectrophotometry analyses revealed titanium present in three of four specimens in levels ranging from 7.92 to 31.8 micrograms/gm of dry tissue. Results from this study revealed trace amounts of titanium in tissues surrounding craniofacial plates. At the atomic level, electrothermal atomic absorption spectrophotometry appears to be a sensitive tool to quantitatively detect ultra-trace amounts of metal in human tissue.

Advances in the treatment of lower extremity wounds applied to military casualties.

A review of six patients with severe lower extremity injuries (four of six with grade IIIB tibia fractures), resulting from combat in Somalia, was undertaken to identify patterns of injury, treatment, and problems unique to combat injuries. An AK-47 gunshot was the mechanism of injury in five of six patients. Muscle flaps were required in all patients (four pedicled muscle flaps and three free vascularized flaps), with five of six patients undergoing flap closure during the subacute phase. Ilizarov devices were used in three of four grade IIIB tibia fractures. Five major nerve injuries were identified in three of six patients. The ballistic effect of an AK-47 to the soft tissues of the extremity is not a high-energy wound as seen in civilian blunt trauma. Knowledge of ballistics and the delay in definitive flap coverage secondary to evacuation allowed definition of zones of injury and successful use of local flaps in the majority of our patients. The high number of nerve injuries not commonly described with blunt trauma may prevent full rehabilitation.