Analysis of gluteal subcutaneous and muscle thickness in infants and children for application to intramuscular injection, autologous fat grafting, and gluteal artery perforator flaps.

BACKGROUND: To achieve improvements in intramuscular injection, autologous fat grafting, and gluteal artery perforator flaps in infants and children, the relationships of computed tomography (CT)-determined gluteal muscle thickness (MT) and subcutaneous tissue thickness (SCT) with age and body mass index (BMI) were analyzed. METHODS: Gluteal SCT and MT at ventrogluteal (VG) and dorsogluteal (DG) sites were measured in a standardized manner in 350 patients aged 0 to 6 years who had visited a tertiary hospital and had undergone abdominopelvic CT between January 2005 and December 2016. Recorded measurements were analyzed using one-way analysis of variance and stepwise multiple regression to identify the factors that were most closely related to MT and SCT. RESULTS: Subcutaneous tissue at VG sites was thinner than at DG sites, but not significantly so in any age group. Muscles tended to be thinner at VG sites in 4 to 7-year-old, but thicker at VG sites in 1 to 3-year-old, though the differences were not significant. MT in the VG and DG regions was found to be related to age, and SCT in these regions to be related to age and BMI. CONCLUSIONS: The VG and DG sites should be considered as alternatives for intramuscular injection in infants and children when the anterolateral site is problematic. In addition, considering the gluteal MT and SCT of infants and children should help produce good results in autologous fat grafting and gluteal artery perforator flap harvesting.

Insulin Promotes Adipose-Derived Stem Cell Differentiation after Fat Grafting.

BACKGROUND: Adipose-derived stem cells are used to enhance fat graft survival. However, their mechanism of action when grafted is controversial. The grafted cells can be replaced by connective tissue or survive at the recipient site and differentiate. Insulin is a powerful agent used to induce their differentiation to adipocytes. The purpose of this study was to elucidate the fate of grafted adipose-derived stem cells in nonvascularized fat grafts with or without insulin. METHODS: Fat was harvested from a female human donor who had undergone reduction mammaplasty. The authors also isolated and cultured adipose-derived stem cells expressing green fluorescent protein from transgenic Sprague-Dawley rats. Injection of free fat graft, the adipose-derived stem cells, phosphate-buffered saline, and insulin was performed on the four paravertebral points of the back of each mouse (n = 30) as follows: group A (control group) received adipose tissue and phosphate-buffered saline; group B received adipose tissue and adipose-derived stem cells; group C received adipose tissue, adipose-derived stem cells, and phosphate-buffered saline; and group D received adipose tissue, adipose-derived stem cells, and insulin. Green fluorescent protein expression was evaluated using an in vivo imaging system. The volume of transplanted fat was evaluated at 8 weeks after graft with six histologic parameters. The fat graft was immunostained with green fluorescent protein, 4',6-diamidino-2-phenylindole, and perilipin. Statistical analysis was performed using a one-way analysis of variance test. RESULTS: The fat graft volume was significantly higher in group D (p < 0.05). Histologic examination revealed reduced fibrosis and increased cysts, vacuoles, integrity, and vascularity in group D. The green fluorescent protein and perilipin co-positive area was more apparent in group D compared with groups B and C. CONCLUSION: Insulin could enhance the survival and differentiation of adipose-derived stem cells in nonvascularized fat grafts.

Merkel Cell Carcinoma of the Wrist: A Case Report.

PURPOSE: Merkel cell carcinomas are a rare type of neuroendocrine tumors of the head, neck, and extremities commonly found in older patients. Merkel cell carcinomas present as red-to-purple and nontender nodules with or without surface ulceration, usually measuring 2 cm in diameter. CASE PRESENTATIONS: An 83-year-old woman with a skin-colored nodule on the dorsal aspect of her right wrist was referred to our department for treatment. The regional lymph nodes were not palpable, and the positron emission tomography/computed tomography scan did not reveal any distant metastases. We conducted wide excision of the lesion and sentinel lymph node biopsy. The defect caused by the excision and partial bone resection was reconstructed using a radical forearm rotational flap and a split-thickness skin graft. Postoperatively, the patient received adjuvant radiation therapy. We observed wound healing and an absence of complications such as recurrence at 1-year follow-up. CONCLUSIONS: Merkel cell carcinomas are rare but aggressive neuroendocrine skin cancers, which rarely occur in the upper extremity. Our treatment of nonamputative wide excision and sentinel lymph node dissection, followed by postoperative radiation therapy, showed no local or distant recurrence. Here, we review the current literature on Merkel cell carcinomas and describe our approach of treatment.

Effect of Platelet-Rich Plasma on Ischemia-Reperfusion Injury in a Skin Flap Mouse Model.

Background: Ischemia-reperfusion (I/R) injury is a leading cause of surgical skin flap compromise and organ dysfunction. Platelet-rich plasma (PRP) is an abundant reserve of various growth factors. Activated platelets play a role in endothelial damage during I/R injury; however, exogenous PRP could inhibit the production of reactive oxygen species. The goal of this study was to investigate the effect of PRP on I/R injury. Methods: Four groups (n=30) of C57BL/6N mice with lateral thoracic artery island flaps were used. Group A, the control group, received flap elevation and repositioning. Group B received PRP and repositioning. Group C had 4 hours of ischemia and then were reperfused. Group D received PRP, had 4 hours of ischemia, and then were reperfused. The survival area of flap tissue and blood perfusion were assessed. Histological evaluation included neutrophil counts. Reactive oxygen species and proinflammatory cytokines were measured to evaluate I/R injury. Protein expression of phosphorylated apoptosis signaling regulating kinase-1 (pASK-1), p38MAPK, and pNF-κB was measured by western blot. Results: PRP treatment enhanced the survival area and perfusion of the flap, reduced neutrophil accumulation in mice subjected to I/R injury. PRP treatment also showed a protective effect, with decreases in nitric oxide, myeloperoxidase, malondialdehyde concentrations. Additionally, PRP suppresses monocyte chemotactic protein-1, TNF-α, IL-1ß, and IL-6. Finally, PRP decreased ASK-1 and NF-κB expression in tissues with I/R injury. Conclusion: PRP acts as a protective factor during flap I/R injury by reducing reactive oxygen species level and proinflammatory cytokines via decreased expression of pASK-1 and pNF-κB.

Influence Factor in Thickness of Cyst Wall of Epidermal Cysts.

PURPOSE: An epidermal cyst is one of the most common benign tumors of the skin and its major treatment method is excision. Surgical excision is treatment of choice for epidermal cysts, but the cyst wall may be ruptured during operation, especially when the cyst wall is relatively thin. The incomplete excision of the cyst sometimes occurs because of a rupture of the cyst and incomplete excision may cause recurrence. The purpose of this study is to evaluate the factors that can influence the thickness of the cyst wall of epidermal cysts. METHODS: From December 2008 to November 2013, medical records and tissue pathology slides of 290 patients with an epidermal cyst were reviewed retrospectively. The relationships among the regions, history of infection, the age of patients, and the thickness of the cyst and epidermis were analyzed. RESULTS: There was no difference between thickness of cyst wall and site of occurrence and between thickness of epidermis and site of occurrence. The thickness of epidermal cyst wall with previous infection is thicker than those without infection episode (P = 0.01). However, the difference of thickness of epidermis above the cyst between with and without previous infection is not statistically significant (P = 0.641). The thickness of cyst wall and epidermis showed positive correlation (Pearson correlation coefficient 0.391, P = 0.01). CONCLUSION: From this study, there was a tendency cyst wall with the history of infection or incision and drainage is thicker. When surgical excision, more attention to excise epidermal cyst completely is needed for the prevention of recurrence of the cyst.