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Cureus Aug 2020The use of minimally invasive endovascular procedures has increased, and as such, the frequency of associated vascular complications has also increased. Regardless of... (Review)
Review
The use of minimally invasive endovascular procedures has increased, and as such, the frequency of associated vascular complications has also increased. Regardless of the access site location, rarely, arterial perforation can occur, which can be fatal if not properly managed. Interventionalists should be aware of the risk factors for perforation, commonly perforated vessels, and how different sites of perforation are diagnosed and managed. Rapid recognition and endovascular management reduce the need for open surgical repair, and thus reduce the morbidity and mortality of these complications. This review outlines the presentation, diagnosis, and management of iatrogenic perforations of the subclavian artery, thyrocervical trunk (TT), common carotid artery, superficial femoral artery (SFA), and external iliac artery.
PubMed: 32983713
DOI: 10.7759/cureus.10018 -
Seminars in Plastic Surgery Aug 2020Various types of propeller flaps from multiple donor sites can be used to reconstruct anterior trunk skin defects. The actual selection depends on the condition and... (Review)
Review
Various types of propeller flaps from multiple donor sites can be used to reconstruct anterior trunk skin defects. The actual selection depends on the condition and location of the recipient site, especially if it is to be the chest or abdomen that requires attention. Before surgery commences, it is always important to use an imaging analyses such as computed tomography angiography to examine and identify perforators that could perfuse a perforator-pedicled propeller flap (PPPF), as it is the most multifaceted imaging technique. Clusters of perforators that can be commonly used for the "workhorse" PPPFs for the thoracic and abdominal regions are the internal mammary artery perforator, the musculophrenic artery perforator, and the deep inferior epigastric perforator. These perforators are reliable and large enough to support long and large propeller flaps that will cover most defects in this region, while still allowing primary donor-site closure.
PubMed: 33041687
DOI: 10.1055/s-0040-1714270 -
Seminars in Plastic Surgery Aug 2020Since propeller flaps are elevated as island flaps and most often nourished by a single perforator nearby the defect, it is challenging to change the flap design... (Review)
Review
Since propeller flaps are elevated as island flaps and most often nourished by a single perforator nearby the defect, it is challenging to change the flap design intraoperatively when a reliable perforator cannot be found where expected to exist. Thus, accurate preoperative mapping of perforators is essential in the safe planning of propeller flaps. Various methods have been reported so far: (1) handheld acoustic Doppler sonography (ADS), (2) color duplex sonography (CDS), (3) perforator computed tomographic angiography (P-CTA), and (4) magnetic resonance angiography (MRA). To facilitate the preoperative perforator assessment, P-CTA is currently considered as the gold standard imaging tool in revealing the three-dimensional anatomical details of perforators precisely. Nevertheless, ADS remains the most widely used tool due to its low cost, faster learning, and ease of use despite an undesirable number of false-positive results. CDS can provide hemodynamic characteristics of the perforator and is a valid and safer alternative particularly in patients in whom ionizing radiation and/or contrast exposure should be limited. Although MRA is less accurate in detecting smaller perforators of caliber less than 1.0 mm and the intramuscular course of perforators at the present time, MRA is expected to improve in the future due to the recent developments in technology, making it as accurate as P-CTA. Moreover, it provides the advantage of being radiation-free with fewer contrast reactions.
PubMed: 33041683
DOI: 10.1055/s-0040-1715159 -
Seminars in Plastic Surgery Aug 2020The reconstruction of complex posterior trunk defects remains challenging. But now with an increased knowledge of angiosomes and the practice of perforator flaps, the... (Review)
Review
The reconstruction of complex posterior trunk defects remains challenging. But now with an increased knowledge of angiosomes and the practice of perforator flaps, the posterior trunk offers a new plethora of options for reconstruction. Propeller flaps based on such perforator(s) offer an elegant solution for managing defects while achieving primary donor-site closure without significant morbidity. We will discuss the relevant anatomy and design principles for propeller flaps based on a review of the literature and our experience. Steps beginning with preoperative planning, perforator selection, and intraoperative surgical technique will be discussed, together with pearls on both avoiding and managing complications.
PubMed: 33041688
DOI: 10.1055/s-0040-1714086 -
Advanced Materials (Deerfield Beach,... Oct 2021Developing bistable metamaterials has recently offered a new design paradigm for deployable structures and reusable dampers. While most bistable mechanisms possess...
Developing bistable metamaterials has recently offered a new design paradigm for deployable structures and reusable dampers. While most bistable mechanisms possess inclined/curved struts, a new 3D multistable shellular metamaterial is developed by introducing delicate perforations on the surface of Schwarz's Primitive shellular, integrating the unique properties of shellular materials such as high surface area, stiffness, and energy absorption with the multistability concept. Denoting the fundamental snapping part by motif, certain shellular motifs with elliptical perforations exhibit mechanical bistability. To bring the concept of multistability to a single motif, multistable shellular motifs are developed by introducing multilayer staggered perforations that form hinges and facilitate local instability. Adopting an n-layer staggered perforation (n hinges) design leads to a maximum 2 stable states within one shellular motif during loading and unloading. Three-directional multistable shellulars are attained by extending the perforation design in three orthogonal directions. Harnessing snap-through and snap-back behaviors and self-contact, the introduced multistable perforated shellulars exhibit strong rigidity both in loading and unloading, and enhanced energy dissipation. The introduced design strategy opens up new horizons for creating multidirectional multistable metamaterials with load bearing capabilities for applications in soft robotics, shape-morphing architectures, and reusable and deployable energy absorbers/dampers.
PubMed: 34467581
DOI: 10.1002/adma.202102423 -
RoFo : Fortschritte Auf Dem Gebiete Der... Jul 2019Intracranial atherosclerotic stenosis (ICAS) causes 5 - 10 % of all ischemic strokes in the European population. Indication for endovascular treatment is a... (Review)
Review
BACKGROUND
Intracranial atherosclerotic stenosis (ICAS) causes 5 - 10 % of all ischemic strokes in the European population. Indication for endovascular treatment is a special challenge and the selection of material as well as interventional techniques essentially differs from the treatment of extracranial stenoses. According to recent studies patient selection became evidence based; however the method should not be abandoned. New technical approaches can contribute to avoid complications.
METHOD
We performed a review of the literature with regard to conservative as well as endovascular treatment of ICAS. Different technical approaches are discussed and strategies to avoid complications are stressed. Based on the treatment indication, the positions of the authorities and the professional societies are taken into account.
RESULTS AND CONCLUSION
A single self-expanding stent is approved for the treatment of ICAS. Balloon mounted and other self-expanding Stents are available for off-label use. Anatomical conditions and features of the stenosis determine the choice of material. Distal wire perforations causing intracranial bleedings may occur during exchange manoeuvres and constitute one of the technical complications in the treatment of ICAS. In contrast, there is hardly any efficient way to eliminate the risk of ischemia in the territory of perforating arteries arising from the intracranial posterior circulation and the middle cerebral artery. The results of the randomized prospective trials strengthen the conservative treatment of ICAS. Endovascular treatment should not be withheld from patients with either hemodynamic stenosis, recurrent ischemic events under best medical treatment in the territory of the stenosed vessel or acute occlusions of a stenosis.
KEY POINTS
· Medical therapy and risk reduction constitute the primary treatment of intracranial stenosis.. · Recurrence under best medical treatment and acute occlusions of intracranial stenosis are indications for endovascular treatment.. · Acute occlusions due to intracranial stenosis often are treated by stenting and angioplasty after mechanical thrombectomy.. · Exchange manoeuvres with distal wire perforation can cause intracranial hemorrhage.. · Basal ganglia and brain stem ischemia constitute a specific risk in treatment of vessel segments bearing perforators..
CITATION FORMAT
· Nordmeyer H, Chapot R, Haage P. Endovascular Treatment of Intracranial Atherosclerotic Stenosis. Fortschr Röntgenstr 2019; 191: 643 - 652.
Topics: Angioplasty, Balloon; Brain Ischemia; Endovascular Procedures; Intracranial Arteriosclerosis; Off-Label Use; Prospective Studies; Randomized Controlled Trials as Topic; Risk Assessment; Stents
PubMed: 30947351
DOI: 10.1055/a-0855-4298