Embolization in Pediatric Patients: A Comprehensive Review of Indications, Procedures, and Clinical Outcomes

Embolization in pediatric patients encompasses a large spectrum of indications, ranging from the elective treatment of congenital diseases of the cardiovascular system to the urgent management of acute hemorrhagic conditions. In particular, the endovascular treatment of central and peripheral vascular malformations and hypervascular tumors represents a wide chapter for both congenital and acquired situations. Thanks to the progressive availability of low-profile endovascular devices and new embolic materials, the mini-invasive approach has gradually overtaken surgery. In this review, the main embolization procedures will be illustrated and discussed, with a focus on clinical indications and expected outcomes. The most recent mini-invasive techniques will be described, with hints on the cutting-edge devices and embolic materials

Metamorphic and structural data of the Monte Filau Orthogneiss, SW Sardinia (Italy)

The Monte Filau Orthogneiss represents the southernmost metaigneous body cropping out in the External Zone of the Variscan chain of Sardinia. It derives from an Ordovician granitoid intruded in the Monte Settiballas Micaschist at about 460 Ma. Three different petrographic facies can be distinguished in the orthogneiss: (i) a dark, biotite-rich facies, (ii) a leucocratic coarse-grained facies and (iii) a leucocratic, fine-grained facies (quartz + plagioclase + K-feldspar + muscovite + biotite ± garnet ± sillimanite ± andalusite). The Monte Filau Orthogneiss shows a polyphasic deformation. The first schistosity is recognizable in the field only in the eastern part of the dome and is evidenced by the orientation of mm-thick quartz-feldspar-bearing porphyroblasts or biotite crystals. The main structure in the field is a N-S striking gneissic pervasive foliation dipping toward West and East in the western and eastern part of the dome, respectively. The foliation is marked by a mm-thick quartz-feldspathic layering that changes to a biotite-bearing gneissic structure in the biotite-rich facies and near the contact with the andalusite-bearing micaschists. In the leucocratic, fine-grained facies the foliation is poorly recognizable except for andalusite-bearing facies in which it is marked by the orientation of andalusite crystals. The NNW-SSE striking mineral lineation gently plunging toward north are highlighted by orientation of biotite on the foliation planes. Late deformational structures include asymmetric folds, shear bands, transposition of mineral lineation and NS striking upright folds. Sillimanite, garnet and andalusite were observed mainly in the leucocratic fine-grained facies. Sillimanite in the fibrolite variety as well as andalusite were observed enclosed in the coarse-grained muscovite. Garnet has been observed as isolated single crystals and in clusters of small crystals oriented along the main schistosity. Worthy of note is the occurrence of dark spindles (term after [1]) up to half a centimeter mainly composed of quartz, feldspar, coarse-grained muscovite and andalusite. In the Western side the gneissic foliation is overprinted by low - temperature (greenschist facies) mylonitic fabric characterized by new growth of quartz, albite, muscovite, and chlorite. In conclusion, the history of Monte Filau Orthogneiss consists of different stages of metamorphic evolution and deformative events recorded in different portion of the orthogneiss. A high-grade metamorphic stage, with P-T conditions P= 3-5 kbar and T near 700 °C, and a later stage under low-temperature conditions (T ca. 400°C) were recognized. Our data support a continuous evolution from amphibolite to greenschist facies with local preservation of high metamorphic grade structures, possibly being consistent with an almost completely Variscan history. References: [1] Mazzoli C and Visonà D (1992) In: Carmignani L and Sassi FP (Eds). IGCP No. 276, Newsletter 5, 175-182

Embolisation of the parenchymal tract after percutaneous portal vein catheterization: a retrospective comparison of outcomes with different techniques in two centres

Background: Embolisation of the parenchymal tract is a key step after any other transhepatic or transplenic percutaneous portal vein catheterization since eventual venous bleeding is difficult to control and may require surgical management. Different techniques have been proposed to perform tract embolisation. The aim of this study is to compare the safety and efficacy of different techniques of haemostasis of the parenchymal tract. Materials and methods: All the interventional procedures with percutaneous transhepatic or transplenic access to the portal vein (excluding ipsilateral portal vein embolisation) from January 2010 to July 2020, in two tertiary hospitals, were retrospectively analyzed. The following data were evaluated: access site, the technique of embolisation, technical success in terms of immediate thrombosis of the tract, safety and clinical efficacy in terms of the absence of hemorrhagic and thrombotic complications. Results: One-hundred-sixty-one patients underwent 220 percutaneous transhepatic or transplenic portal vein catheterization procedures. The main indications were pancreatic islet transplantation, portal anastomotic stenosis after liver transplantation, and portal vein thrombosis recanalization. As embolic materials gelfoam was used in 105 cases, metallic micro-coils in 54 cases, and cyanoacrylic glue in 44 cases; in 17 cases the parenchymal tract was not embolized. Technical success was 98% without significant difference among groups (p-value = 0.22). Eighteen post-procedural abdominal bleedings occurred, all grade 3 and were managed conservatively; difference among groups was not significant (p-value = 0.25). We detected 12 intrahepatic portal branch thromboses not related to the embolisation technique; only one case of non-target embolisation was documented after liver tract embolisation with glue, without clinical consequences. Conclusion: Embolisation of the parenchymal tract after percutaneous portal vein catheterization is technically safe and effective. No significant differences were found between coils, glue, and gelfoam in effectiveness and complications rate. Level of evidence: Level 3, Cohort study