Distally Based Perforator-Plus Sural Neurocutaneous Flap with High or Low Pivot Point: Anatomical Considerations and a Retrospective Study of a Clinical Series of 378 Flaps.

BACKGROUND: This study is to describe the distribution of natural true anastomoses associated with the distally based perforator-plus sural neurocutaneous flap (sural flap), summarize our experience in the flap with high pivot point, and compare the outcomes between the flaps with high and low pivot points. METHODS: Five amputated lower limbs were perfused, and the integuments were radiographed. We retrospectively analyzed 378 flaps, which were divided into two groups: pivot points located ≤8.0 cm (low pivot point group) and >8.0 cm (high pivot point group) proximal to the tip of the lateral malleolus. Partial necrosis rates were compared between two groups. RESULTS: The arterial chain surrounding the sural nerve was linked by true anastomoses from the intermalleolar line to popliteal crease. True anastomoses existed among peroneal perforators and between these perforators and the arterial chain. There were 93 flaps with high pivot point and 285 flaps with low pivot point. Partial necrosis rates were 16 and 9.1% in the high and low pivot point group (p = 0.059), respectively. CONCLUSION: True anastomosis connections among peroneal perforators and the whole arterial chain around sural nerve enable the sural flap to survive with a greater length. The sural flap with high pivot point is a good option for reconstructing soft-tissue defects in the middle and distal leg, ankle, and foot, particularly when the lowest peroneal perforator presents damage, greater distance to the defects, discontinuity with the donor site, or anatomical variation.

Development of an immune-related prognostic index associated with osteosarcoma.

Tumor immunity is closely associated with the prognosis of tumors, including osteosarcoma (OS). The aim of the present study was to construct an immune-related prognostic index (PI) to predict the prognosis of OS. Herein, OS expression data were sourced from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database. We divided the OS patients into nonmetastatic and metastatic groups, allowing differentially immune-related genes (DIRGs) to be selected. After DIRGs were further investigated by enrichment analysis, four keys prognostic IRGs (CD79A, CSF3R, MTNR1B and NPPC) were identified using a Cox proportional hazards model. Then, an immune-related prognostic index was constructed. Finally, gene set enrichment analysis (GSEA) was employed to further explore the underlying mechanisms. The difference in tumor-infiltrating immune cell (TIIC) abundance was also discussed. In our study, eight upregulated genes and 30 downregulated genes were identified. Several Gene Ontology (GO) terms and the most significantly enriched KEGG pathways were immune-associated functions and pathways. Four genes, including CD79A, CSF3R, MTNR1B and NPPC, were used to establish a risk assessment model for evaluating OS prognosis. GSEA revealed that the risk score was related to cytokine receptor interaction and to the chemokine and B cell receptor signaling pathways. Furthermore, high risk markedly related to the infiltration of several immune cell types, including M2 macrophages, naïve CD4 T cells, and CD8 T cells. In sum, we developed a survival model for OS. The underlying molecular mechanisms of the high-risk group may affect immune-related biological processes and TIICs.Abbreviations TARGET: Therapeutically Applicable Research To Generate Effective Treatments; PI: Prognostic index; OS: Osteosarcoma; DIRGs: Differentially immune-related genes; GSEA: Gene set enrichment analysis; TIIC: Tumor-infiltrating immune cell.