Review of best classification systems for diagnosing and treating thoracolumbar spine trauma

Background: Improved thoracolumbar spine trauma classification (TLSTC) systems can better help diagnose and treat thoracolumbar spine trauma (TLT). Here, we identified the types of injury (rationale and description), instability criteria, and treatment guidelines of TLSTC. Methods: We used the PubMed/MEDLINE database to assess TLSTC according to the following variables: injury morphology, injury mechanism, spinal instability criteria, neurological status, and treatment guidelines. Results: Twenty-one studies, 18 case series and three reviews were included in the study. Treatment guidelines were proposed in 16 studies. The following three major parameters were identified in TLSTC studies: injury morphology (19/21 studies), posterior ligamentous complex (PLC) disruption alone as the main spinal instability criterion (15 studies), and neurological damage (12 studies). Most classification systems neglected the severity of vertebral body comminution. Conclusion: We identified here the 3 main parameters for the evaluation of diagnosis and treatment of TLT: injury morphology, PLC disruption, and neurological damage. Based on our review, we may conclude that further clinical validation studies of TLSTC are warranted.

On the stability and instability criteria for circulatory systems: A review

A survey of the selected published criteria - expressed by the properties of the system matrices - for the stability and instability of linear mechanical systems subjected to potential and circulatory forces is presented. In particular, recent generalizations of the well-known Merkin instability theorem are reported. Several simple numerical examples are used to illustrate the usefulness of the presented criteria and also to compare them.

Doppler Radar Observations of Horizontal Shearing Instability in Quasi-Linear Convective Systems

Dual-Doppler radar observations of two cold-season, wave-propagating quasi-linear convective systems (QLCS), which evolved in high-shear, low-CAPE (HSLC) environments, are analyzed to determine the role that horizontal shearing instability (HSI) plays in the formation of mesovortices. One QLCS occurred on 4 January 2015 and produced two mesovortices within the dual-Doppler region, one of which was associated with an EF-1 tornado with a pathlength of 10 km. The second QLCS occurred on 28 November 2016 and did not produce any mesovortices. Storm characteristics such as the low-level wind speed and wind shift angle are investigated. Rayleigh and Fjørtoft instability criteria, which are required but insufficient for HSI, are also examined. The Rayleigh and Fjørtoft instability criteria are satisfied for the 4 January 2015 QLCS and the 28 November 2016 QLCS, highlighting one of the issues of the “required, but insufficient” characteristic of the criteria. Analysis of the wind shift angle and wind speed agree with previous studies that pronounced wind shifts close to 90° and strong wind speeds were conducive to the formation of mesovortices, while weak wind shift angles and weaker wind speeds were not. It was found that for the 4 January 2015 case, HSI was the likely formation mechanism of the vortices as other features associated with preexisting mesovortexgenesis theories were not observed.