Diagnostic accuracy of upper gastrointestinal series in children with suspected intestinal malrotation

Intestinal malrotation (IM) results from an altered or incomplete rotation of the fetal midgut around the superior mesenteric artery axis. The abnormal anatomy of IM is associated with risk of acute midgut volvulus which can lead to catastrophic clinical consequences. The upper gastro-intestinal series (UGI) is addressed as the gold standard diagnosis procedure, but a variable failure degree has been described in literature. The aim of the study was to analyze the UGI exam and describe which features are the most reproducible and reliable in diagnosing IM. Medical records of patients surgically treated for suspected IM between 2007 and 2020 at a single pediatric tertiary care center were retrospectively reviewed. UGI inter-observer agreement and diagnostic accuracy were statistically calculated. Images obtained with antero-posterior (AP) projections were the most significant in terms of IM diagnosis. Duodenal-Jejunal Junction (DJJ) abnormal position resulted to be the most reliable parameter (Se = 0.88; Sp = 0.54) as well as the most readable, with an inter-reader agreement of 83% (k = 0.70, CI 0.49-0.90). The First Jejunal Loops (FJL), caecum altered position and duodenal dilatation could be considered additional data. Lateral projections demonstrated an overall low sensitivity (Se = 0.80) and specificity (Sp = 0.33) with a PPV of 0.85 and a NPV of 0.25. UGI on the sole AP projections ensures a good diagnostic accuracy. The position of the third portion of the duodenum on lateral views showed an overall low reliability, therefore it was not helpful but rather deceiving in diagnosing IM.

Hallux varus: a step-wise approach for correction

Iatrogenic hallux varus can be an unfortunate complication of hallux abducto valgus surgery. The correction of hallux varus must be performed in a well planned, step-wise method. The authors present both soft tissue and osseous corrections for hallux varus, with two case reports.

Peripheral nerve block with use of nerve stimulator

The authors describe use of the nerve stimulator in conjunction with a percutaneous exploring needle to achieve peripheral blocks accurately and without injuring the nerve. The nerve stimulator allows accurate nerve blocks without causing paresthesiae and the need for additional anesthetic. This technique decreases the possibility of nerve injury.

Molecular weight distribution of block copolymers by gel permeation chromatography

Molecular weight distributions for block copolymers of polystyrene and polyisoprene have been determined by gel permeation chromatography for a series of well characterized polymers. Universal calibration curves from [η]M against elution volume and by plots of unperturbed dimensions (ro2)� against elution volume have been constructed and examined. Normal-probability curves have been used to calculate the heterogeneity ratio MW/MN and the results compared with values from light scattering measurements and from osmometry.

Conformational transitions in block copolymers in solution from light scattering data

Data obtained from light scattering studies on block copolymers of styrene and isoprene, in the solvent cyclohexane, show a change in apparent radius of gyration as a function of temperature at the same temperature, Tp, as was observed in studies of [η] against T in this solvent. The phenomenon observed in these independent experimental methods is believed to be due to a change in the hydrodynamic volume of the polymer, brought about by an intramolecular rearrangement of the molecule, from a phase-separated to a phase-mixed conformation, as the temperature increases through Tp.