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.

Patterns of facial laceration from blunt trauma.

The clinical characteristics of craniofacial injuries resulting from various modes of blunt trauma, including motor vehicle accidents, falls, and assault, have been described extensively in the literature. In this study, specifically targeted blunt trauma to selected areas of the face was used to recreate soft-tissue laceration injuries on 19 cadaver heads. The patterns of laceration produced were then examined by location, size, penetrated skin depth, and associated muscle and bony involvement. Results showed reproducible patterns of lacerations on the forehead, bilateral superior orbital rim, nose, perimaxillary region, and chin. Six of 19 cadaver faces were undermined prior to blunt trauma to determine the effects of subcutaneous attachments on laceration patterns. Results showed no consistent difference in laceration patterns between undermined skin and intact skin. Our findings suggest that in response to blunt trauma, the skin breaks along selected lines of least resistance that closely parallel cleavage lines of the face and that the patterns of laceration generated are associated with inherent structural and biomechanical properties of the skin, independent of subcutaneous attachments. Blunt trauma lacerations to the face therefore may occur in a consistent and reproducible manner and may be subject to classification.

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.

Progressive hemifacial atrophy (Parry-Romberg syndrome). Case report.

Progressive hemifacial atrophy (Parry-Romberg syndrome) is a slowly progressing facial atrophy of subcutaneous fat and the wasting of associated skin, cartilage, and bone. This disorder includes an active progressive phase (2 to 10 years) followed by a burning out of the atrophic process with subsequent stability. This article presents a review of the literature and a case report with unique dental involvement as a result of this disease process.

Clinical perspectives on bone grafting. Avoiding the complications of developmental malformations.

Bone graft options are reviewed for various sites in the craniofacial skeleton, as are the mechanical and physiologic requirements for different recipient sites. The potential for complications is discussed, as are the prevention and treatment of complications.

Microcystic adnexal carcinoma (sclerosing sweat duct carcinoma).

Microcystic adnexal carcinoma (MAC) is a recently described malignant neoplasm of the adnexal structures of skin that shows a marked propensity for early infiltrative and locally aggressive growth. Its banal clinical appearance may lead to a delay in diagnosing the tumor by biopsy, and its multifaceted histologic features may lead to an incorrect tissue diagnosis. Confusion with benign tumors and less aggressive malignancies can lead to inadequate initial treatment and extensive recurrences. We describe three cases of microcystic adnexal carcinoma and review the clinical and histologic features, treatment, and prognosis of this neoplasm.

Treatment of avulsion injuries with porcine skin xenografts.

Porcine skin functions efficiently in the treatment of avulsion injuries. It is used as a temporary biologic dressing to prepare sites of avulsions for optimal healing of flaps or autografts. It also contributes to the healing process by preventing desiccation of the wound and by enhancing re-epithelialization.