Reconstruction of total upper eyelid with prefabricated capsule-lined advancement flaps.

BACKGROUND: A total upper eyelid defect is a rare problem that may result from tumor excision, trauma, or burns. Reconstruction of a total upper eyelid defect involves the reconstruction of 2 fundamental elements: anterior and posterior lamellae. Because an expander capsule looks like the palpebral conjunctiva with a moist, smooth, white glistening appearance, its use was investigated in the repair of total upper eyelid defects in rabbits. METHODS: Sixty-six tissue expanders with the autogeneic conchal chondro-grafts were implanted into the foreheads of 66 rabbits. After 6 to 8 weeks, the sandwich-prefabricated advancement flaps were designed to reconstruct rectangular excisions of the upper eyelid. The cartilage was preliminarily inserted in a flap, formed by tissue expansion, and then transferred to an upper eyelid defect in the rabbit. Histopathology was evaluated at 3 days, 1 week, 2 weeks, 1 month, 2 months, and 4 months after reconstruction. The upper palpebral length was measured after 4 months of reconstruction as a 1-dimension reference point of flap contracture. RESULTS: No edema, congestion, infection, corneal damage, or necrosis were observed during the reconstructions. Histopathologic studies revealed that the long-term capsule had a normal conjunctiva-like appearance with a stratified columnar epithelium. The average shortening, measured as the length between inner to outer canthal folds, was inconspicuous. CONCLUSIONS: The expander capsule has the potential to act as an effective posterior lamellar substitute of eyelid in a rabbit model. Further studies should be undertaken to see if this represents a good model for a potential human clinical application.

[Complications of head and neck skin expansion]. / Complications de l'expansion cutanée cervico-faciale.

INTRODUCTION: Skin expansion is a good solution for the reconstruction of head and neck defects. We assessed the complications of cervico-facial skin expansion technique to draft recommendations so as to minimize risks. METHODS: We made a retrospective study from 1990 to 2005. Complications were analyzed according to age, sex, etiology, area to reconstruct, location of the expander, expander volume and number, simultaneous single or repeated technique, type of expander, duration of expansion, and type of flap used for reconstruction. RESULTS: One hundred and thirty-nine tissue expanders were placed in 114 patients. The rate of complications was 60.4%. Age was not a risk factor (P=0.21; Fisher's exact test). The early complications were not related to the expander volume (P=0.32; Fisher's exact test). Infection was the most frequent complication (51.3%). Hypertrophic or large scars, retraction, or cording accounted for 32.4% of sequels. A rate of 6.5% of total and 6.5% of partial failure were recorded. Infection was the cause of 77.8% of total or partial failure. DISCUSSION: The complications of head and neck soft tissue expansion are often minor. The rate of reconstruction failure remains acceptable.

Guided bone generation in a rabbit mandible model after periosteal expansion with an osmotic tissue expander.

OBJECTIVES: To evaluate the space-maintaining capacity of titanium mesh covered by a collagen membrane after soft tissue expansion on the lateral border of the mandible in rabbits, and to assess bone quantity and quality using autogenous particulate bone or bone-substitute (Bio-Oss(®) ), and if soft tissue ingrowth can be avoided by covering the mesh with a collagen membrane. MATERIAL AND METHODS: In 11 rabbits, a self-inflatable soft tissue expander was placed under the lateral mandibular periosteum via an extra-oral approach. After 2 weeks, the expanders were removed and a particulated onlay bone graft and deproteinized bovine bone mineral (DBBM) (Bio-Oss(®) ) were placed in the expanded area and covered by a titanium mesh. The bone and DBBM were separated in two compartments under the mesh with a collagen membrane in between. The mesh was then covered with a collagen membrane. After 3 months, the animals were sacrificed and specimens were collected for histology. RESULTS: The osmotic soft tissue expander created a subperiosteal pocket and a ridge of new bone formed at the edges of the expanded periosteum in all sites. After the healing period of 3 months, no soft tissue dehiscence was recorded. The mean bone fill was 58.1±18% in the bone grafted area and 56.9±13.7% in the DBBM area. There was no significant difference between the autologous bone graft and the DDBM under the titanium mesh with regard to the total bone area or the mineralized bone area. Scanning electron microscopy showed that new bone was growing in direct contact with the DBBM particles and the titanium mesh. There is a soft tissue ingrowth even after soft tissue expansion and protection of the titanium mesh with a collagen membrane. CONCLUSION: This study confirms that an osmotic soft tissue expander creates a surplus of periosteum and soft tissue, and that new bone can subsequently be generated under a titanium mesh with the use of an autologous bone graft or DBBM.

A histologic analysis of three-dimensional versus two-dimensional tissue expansion in the porcine model.

OBJECTIVE: Recently, a two-dimensional Silastic Dacron stretching skin device has been developed for scalp reduction surgery. Attached subgaleally, this device stretches skin over time, while avoiding the visible volumetric distention that is typical of three-dimensional tissue expanders. Unlike three-dimensional expanders, the histological changes observed with a two-dimensional stretching device have not been described in the literature. The present study compares the histological effects of two-dimensional and three-dimensional skin tissue expansion in the porcine model. STUDY DESIGN: A university Institutional Review Board-approved study in which 16 domestic piglets were used. The 16 piglets were divided evenly into four cohorts as follows: 1, 1-week control cohort; 2, 1-week experimental cohort; 3, 4-week control cohort; and 4, 4-week experimental cohort. METHODS: Tissue expanders (three-dimensional) and Dacron Silastic tissue stretchers (two-dimensional) were surgically inserted into the lateral skin of 16 domestic pigs. Animals were killed at either 1 or 4 weeks based on group assignment. Light microscopic ocular micrometry and stereological point counting were used to determine the depth of the epidermis, dermis, and subdermal adipose tissue layer; width of the panniculus muscle; diameter of sweat gland follicles; percentage ratio of dermal collagen, blood vessels, and tissue space; and epidermal mitotic index in 100 specimens. One-way ANOVA was used to evaluate statistical differences. RESULTS: Both tissue expanders yielded increased values compared with control subjects, with respect to epidermal, dermal, and fat widths and blood vessel counts, whereas adnexal structures in the panniculus muscle width were unaltered. CONCLUSIONS: Although statistically the two types of expansion produced histologically similar changes, the degree of change varied according to the type of expander that was used and the duration of tissue expansion. Most notably, three-dimensional expansion produced more tissue gain per unit area expanded at both the 1-week and the 4-week time intervals, and early (1-week) two-dimensional tissue expansion stimulated a greater angiogenic response than three-dimensional expansion. These findings will assist the surgeon in understanding the physical changes that occur with these two forms of tissue expansion, as well as the potential clinical advantages and shortcomings of each method.