Study Design: In vitro experimental study.
Objective: This study aimed to evaluate the biomechanical properties of bicortically placed and laterally oriented screws, which may represent an alternative approach for challenging sites during direct vertebral rotation (DVR).
Summary Of Background Data: DVR corrects the transverse plane deformity and the thoracic hump in idiopathic scoliosis. However, instrumentation of the convex side of the scoliosis apex may pose a challenge, not allowing the placement of suitable sized screws in adequate direction.
Methods: Forty-eight calf vertebrae were used and each vertebral body was instrumented with 1 pedicle screw as follows: unicortical group (n=16), a short screw was unicortically placed and directed laterally; bicortical group (n=16), a short screw was bicortically placed again in lateral direction; control group (n=16), a screw with ideal length and direction was placed. Vertebral bodies were rigidly anchored in a custom device. Each screw was rotated using a constant length lever arm while collecting "force to failure" data.
Results: Significantly better results were obtained with bicortical screwing when compared with unicortical screwing (335.4±45.6 vs. 239.5±58.50 N, P<0.001). However, mean "force to failure" was significantly higher in the controls than in the bicortical group (415.8±49.2 vs. 335.4±45.6 N, P<0.001).
Conclusions: Bicortical screw placement may provide a biomechanically superior construct than unicortical screw placement for resisting DVR maneuver during scoliosis correction. This technique may represent an effective and safe approach, particularly for the convex side of the scoliosis apex, with increased resistance to derotational forces and decreased risk of bone failure. Further clinical studies are warranted for firmer conclusions.
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http://dx.doi.org/10.1097/BSD.0b013e31825dd542 | DOI Listing |
World J Gastrointest Surg
February 2020
Department of Hepatobiliary Surgery and Pancreatic Surgery, Queen's Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham NG7 2UH, United Kingdom.
Background: Above and beyond their role in cardiovascular risk reduction, statins appear to have a chemopreventive role in some gastro-intestinal cancers. In the quest for new chemopreventive agents, some existing established drugs such as statins have shown potential for re-purposing as chemoprevention. Probing existing drugs, whose pharmacodynamics are familiar, for novel beneficial effects offers a more cost-effective and less time-consuming strategy than establishing brand new drugs whose pharmacodynamic profile is unfamiliar.
View Article and Find Full Text PDFObjectives: To compare outcomes of care in selected neonatal intensive care units (NICUs) for very low birthweight (VLBW) or preterm infants in Scotland and Australia (study 1) and perinatal care for all VLBW infants in both countries (study 2).
Design: Study 1: risk adjusted cohort study; study 2: population based cohort study.
Subjects: Study 1: all 2621 infants of < 1500 g birth weight or < 31 weeks' gestation admitted to a volunteer sample of hospitals comprising eight of all 17 Scottish NICUs and six of all 12 tertiary NICUs in New South Wales and Queensland in 1993-1994; study 2: all 5986 infants of 500-1499 g birth weight registered as live born in Scotland and Australia in 1993-1994.
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