Retro-orbital intraconal fat injection: an experimental study in rabbits.

PURPOSE: Despite adequate treatment, enophthalmos due to intraconjunctival corticosteroid injection and enlargement of the bony orbit after trauma remains a frequent complication. The use of alloplastic material in addressing this problem is restricted because it may result in allergic reactions and is not cost-effective. The use of retro-orbital intraconal injection is the most effective method for maximum augmentation. An inexpensive and minimally invasive alternative that also allows for reoperation when needed would be a preferred intervention. MATERIALS AND METHODS: We used 24 white rabbits (New Zealand) in our study. The animals were divided into 2 groups: a fat group and a saline solution group. The first group was subjected to retrobulbar fat injection, and the second group underwent physiologic saline solution injection. The volume of the retrobulbar area was measured and statistically evaluated both before and after the injections. Sonographically measured retrobulbar volumes were then statistically analyzed. RESULTS: When the saline solution and fat groups were compared, no significant difference was observed between the preinjection volumes of the orbits. However, after injection, there was a significant difference between volumes. A statistically significant difference was shown between retro-orbital volumes calculated before the injection in the fat group and volumes calculated immediately after injection and in the following 4 months (right retro-orbital volume of 1.291 cm(3) ± 0.031 cm(3) before injection and 2.656 cm(3) ± 0.040 cm(3) in the fourth month, P < .05). CONCLUSIONS: Volume augmentation by fat injection is superior to complicated surgical methods because of the advantages of decreased morbidity, rapid rehabilitation, and ease of reinjection. Using fat tissue as a filling material is more reliable, easier, and cheaper in comparison to other implantable materials.

The effects of thermal injury on immature rat ear cartilage.

The purpose of this study was to research regeneration and growing properties of an immature rat ear cartilage and its adjacent tissue after a thermal injury. Fifteen 30-day-old male Sprague-Dawley rats were used. Burn wounds were created by applying a heated plaque. All the rats, based on their tissue sampling day, were placed in two groups for histopathologic evaluation. In group I (n = 5), the burned right auricles were amputated on the first day,and the left auricles were amputated as a control at the same time. In group II (n = 10), the burned right auricles were amputated on the 30th day, and the left auricles were amputated as a control at the same time. Epithelization of skin was completed in period ranging between 12 and 15 days in all burned ears. The skin appendages were few throughout the affected area.Chondroid tissue regenerated from perichondrium and increased capillary vessels were observed.On the first day of the burn injury, electron microscopic findings were karyopyknosis, karyorrhexis, and karyolysis of the nucleus, and there were also signs of necrosis. New chondroblasts were formed around the collagen fibrils in the scar tissue on the 30th day. CD-31 immunohistochemical staining showed increased capillary vessels in the burned ear. The peripheral nerve fibers decreased and regenerative signs of nerves were shown with the use of S-100 immunohistochemical staining. Differentiation of chondroblasts to chondrocytes occurs in the burned immature ear, and new cartilage tissue regenerates from perichondrium. In addition, regenerative signs of nerves appear.

Bone flap prefabrication: an experimental study in rabbits.

The usual method to prefabricate a bone flap is to harvest a nonvascularized bone graft and to implant the artery and vein bundle between segments of bone graft. The basic problem of this method is sacrificing an artery for prefabrication. Another method for creating flap donor sites without using an artery is venous flap prefabrication. There are a few articles describing bone flap prefabrication, and these include implantation of both artery and vein as a vascular bundle. Also, there is no experimental study in the literature using a vein or an arterialized vein pedicle for bone flap prefabrication. As an experimental model for bone flap prefabrication, the rabbit ear vascular model was chosen. For the experiments 3 groups were formed. Each group contained 5 rabbits. In the first experimental group a vein was implanted between the halves of bone graft. In the second experimental group an arterialized vein was implanted between the halves of bone graft. To compare the viability of the bone graft of the 2 prefabrication groups, a bone graft was implanted into the subcutaneous pocket of the posterior auricular area in the third group. The authors examined 5 rabbits in each group by microangiography at the end of 6 weeks except for group 3. On microangiographic analysis, groups 1 and 2 showed patency of the vascular pedicle. There was no difference between these 2 groups from the point of view of vascular patency and bone appearance. Bone scintigraphy was performed for 5 rabbits in each group. On bone scintigraphic scans, the bone component of the flaps was visualized in groups 1 and 2, but not in group 3. A quantitative analysis of images was performed by drawing symmetric spherical regions of interest (ROIs) over both the implanted area and cranial bone. The uptake ratios were computed by dividing the mean counts in the implanted ROI by mean counts in the cranial bone ROI. The mean value was 0.86 +/- 0.02 in group 1 and 0.86 +/- 0.04 in group 2. A statistically significant uptake difference was not seen between venous and arterialized venous groups (P < 0.01). Histologic examination was performed all rabbits in each group, and demonstrated that the bony component was viable, showing osteocytes containing lacunae, osteoblasts along bony trabeculae, and vascular channels in groups 1 and 2. In group 3, the bony architecture of the graft was still apparent, but all bone within it was dead. There were no significant microangiographic, histologic, and scintigraphic differences between the 2 experimental methods.

Salivary duct carcinoma of the parotid gland metastasizing to the skin: a case report and review of the literature.

Salivary duct carcinomas of parotid gland are rare, as are the skin metastases from them. Four cases are reported with metastases to the skin. We present an additional case, with subcutaneous metastases of the back and leg. To our knowledge, this is the first case reported in the literature in which the nodule on an extremity was the metastasis of a salivary duct carcinoma of parotid gland.

The fate of intramuscularly injected fat autografts: an experimental study in rabbits.

An experimental study was designed to assess the viability and revascularization of intramuscularly injected fat autografts. For the study, 18 rabbits were divided into two groups. In the first group, fat was injected intramuscularly (12 rabbits). Autologous fat was obtained from the inguinal area and subsequently injected into the thigh muscle. In the second group, physiologic saline was injected intramuscularly to determine the effects of cannulation and pressure on muscle tissue (6 rabbits). Fat autografts were performed on the right side of the animal, and the left side was used as the control. Scintigraphic imaging and histopathologic examination of the limbs were performed after injection of adipose tissue on days 15, 30, 45, 60, 90, and 120. On the technetium-99m ((99m)Tc) hexamethylpropylene amine oxime scintigraphy, whereas similar activity distribution was observed between the left and right thigh on days 15, 30, and 45, there was increased uptake at the right thigh on days 60, 90, and 120. This increased uptake indicates that there is viable fat tissue in this region. Histopathologic evaluation showed that microcysts resulting from degeneration of some adipocytes and inflammatory changes on day 15 additionally increased vascularity and fibrosis in some animals on day 30, as well as fibrosis, microcysties, and focal calcification areas in adipose tissue on day 45 and later. It was observed that adipose tissue survived in more than 50% of the graft area in all the animals. These findings show that fat autografts can survive in muscle tissue with less than 50% fibrotic change.