Background Ultrasound-guided regional anesthesia (UGRA) is increasingly used by emergency physicians to provide safe and effective pain relief for patients. However, one of the factors limiting its widespread use is the lack of realistic models available for learners to train on. There are currently no inexpensive nerve block models available that are injectable and that closely mimic nerves, fascial planes, muscles, and other landmarks. Our aim is to create inexpensive, injectable nerve block models that can be used as effective medical training tools for UGRA. Methods By using a lean cut of pork such as pork loin, yarn soaked in ultrasound gel to simulate peripheral nerves, and drinking straws filled with gel to represent vascular structures, we created various nerve block models. Meat glue applied between sections of meat appears hyperechoic under ultrasound, thereby mimicking fascial planes and has the added benefit of helping to secure the components of the model together. Using these elements, we were able to create realistic peripheral nerve, fascia iliaca compartment, serratus anterior plane, and interscalene brachial plexus models. Results One of the necessary skills in performing UGRA involves placing the needle tip along a fascial plane and visualizing hydrodissection of this plane with the local anesthetic. When meat glue (transglutaminase) is applied between layers of meat such as pork loin, the meat binds together and creates a hyperechoic line that mimics a fascial plane. When meat glue is applied to two apposing fascial layers naturally occurring on the meat, the fascial plane can be injected, and fluid can be seen hydrodissecting in this space. We created several nerve block models using meat glue and other components to mimic normal landmarks. Conclusions We have developed inexpensive and easily reproducible models that create the realistic appearance of tissues, nerves, and fascial planes under ultrasound. They can also accurately simulate hydrodissection of fluid in fascial planes. We hope these nerve block models will allow for the education in UGRA to be more widespread and accessible to learners from all specialties. Electronic supplementary material The online version of this article (10.1186/s12909-019-1591-1) contains supplementary material, which is available to authorized users.

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The rhodium(II)-catalyzed oxidative cyclization of glycal 3-carbamates with in situ incorporation of an alcohol nucleophile at the anomeric position provides access to a range of 2-amino sugars having 1,2-trans-2,3-cis stereochemistry, a structural motif present in compounds of medicinal and biological significance such as the streptothricin group of antibiotics and the Chitinase inhibitor allosamidin. All of the diastereomeric d-glycal 3-carbamates have been investigated, revealing significant differences in anomeric stereoselectivity depending on substrate stereochemistry and protecting groups. In addition, some substrates were prone to forming C3-oxidized dihydropyranone byproducts under the reaction conditions. Allal- and gulal 3-carbamates provided uniformly high stereo- and chemoselectivity, while for glucal substrates, acyclic, electron-withdrawing protecting groups at the 4 O and 6 O positions were required. Galactal 3-carbamates have been the most challenging substrates; formation of their amidoglycosylation products is most effective with an electron-withdrawing 6 O-Ts substituent and a sterically demanding 4 O-TBS group. These results suggest a mechanism whereby conformational and electronic factors determine the partitioning of an intermediate acyl nitrenoid between alkene addition, leading to amidoglycosylation, and C3-H insertion, providing the dihydropyranone byproduct. Along the amidoglycosylation pathway, high anomeric selectivity results when a glycosyl aziridine intermediate is favored over an aziridine-opened oxocarbenium donor.

Ovarian torsion is a surgical emergency that can be difficult to diagnose and can therefore lead to delayed treatment and loss of ovarian function. While the diagnosis of ovarian torsion is based clinically, several sonographic findings can suggest ovarian torsion, including an enlarged ovary, presence of an ovarian cyst or mass, or abnormal ovarian blood flow. Less commonly described is the finding of an abnormal ovarian location in a clinical setting concerning for torsion. We present three cases of ovarian torsion where an ultrasonographic finding of a “double bladder sign” aided in early detection of ovarian torsion.