RESUMEN
OBJECTIVES: We performed a meta-analysis to examine the performance of second-trimester (14-24 weeks' gestation) isolated fetal pyelectasis as a marker for trisomy 21 and to calculate its associated weighted pooled likelihood ratios. METHODS: PubMed, Ovid MEDLINE and Cochrane databases were searched using the terms 'pyelectasis' and 'pelviectasis'. Studies were included if fetuses with isolated pyelectasis were reported separately from fetuses with other soft markers of aneuploidy and/or structural anomalies and if knowledge of the fetal karyotype was unknown at the time of ultrasound examination. RESULTS: Individual study statistics were pooled as weighted positive and negative likelihood ratios with 95% CIs, using a random-effects model. Ten observational studies were included (2148 cases of isolated pyelectasis). Isolated fetal pyelectasis was defined in seven out of 10 studies as a renal pelvis anteroposterior diameter of ≥ 4 mm. Isolated fetal pyelectasis was associated with pooled positive and negative likelihood ratios of 2.78 (95% CI, 1.75-4.43) and 0.99 (95% CI, 0.98-1.00), respectively. CONCLUSIONS: The detection of isolated fetal pyelectasis on mid-trimester ultrasound is associated with an increased likelihood of trisomy 21. If the finding of isolated fetal pyelectasis is used to adjust the trisomy 21 risk from maternal serum screening tests, a positive likelihood ratio of 2.78 should be used in the calculation.
Asunto(s)
Síndrome de Down/epidemiología , Pielectasia/epidemiología , Femenino , Humanos , Pelvis Renal/diagnóstico por imagen , Funciones de Verosimilitud , Embarazo , Segundo Trimestre del Embarazo , Pielectasia/diagnóstico por imagen , Riesgo , Ultrasonografía PrenatalRESUMEN
This article presents a series of 49 km/h sled tests using the Hybrid III 6-year-old dummy in a high-back booster, a low-back booster, and a three-point belt. Although a 10-year review at a level I trauma center showed that noncontact cervical spine injuries are rare in correctly restrained booster-age children, dummy neck loads exceeded published injury thresholds in all tests. The dummy underwent extreme neck flexion during the test, causing full-face contact with the dummy's chest. These dummy kinematics were compared to the kinematics of a 12-year-old cadaver tested in a similar impact environment. The cadaver test showed neck flexion, but also significant thoracic spinal flexion which was nonexistent in the dummy. This comparison was expanded using MADYMO simulations in which the thoracic spinal stiffness of the dummy model was decreased to give a more biofidelic kinematic response. We conclude that the stiff thoracic spine of the dummy results in high neck forces and moments that are not representative of the true injury potential.
Asunto(s)
Accidentes de Tránsito , Vértebras Cervicales/lesiones , Vértebras Cervicales/fisiopatología , Maniquíes , Traumatismos del Cuello/etiología , Traumatismos del Cuello/fisiopatología , Fenómenos Biomecánicos , Niño , Humanos , Equipo Infantil , Modelos Biológicos , Movimiento (Física) , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Medición de RiesgoRESUMEN
This paper presents a series of 49 km/h sled tests using the Hybrid III 6-year-old dummy in a high-back booster, a low-back booster, and a three-point belt. Although it is shown that non-contact cervical spine injuries are rare in correctly restrained children in this age group, neck loads exceeded published injury thresholds in all tests. The dummy kinematics were compared to the kinematics of a 12-year-old cadaver tested in a similar impact environment. This comparison was expanded using MADYMO simulations. It is concluded that the stiff thoracic spine of the dummy results in high neck forces and moments that are not representative of the true injury potential.