Practice guidelines for prevention of musculoskeletal disorders in obstetric sonography.

Ergonomics and prevention of musculoskeletal disorders in obstetric sonography is a subject seldom discussed. However, 80% of sonographers describe pain when performing these examinations. The consequences of these disorders can range from impaired quality of life to the complete cessation of professional activity. Some diseases may even require surgical treatments such as carpal tunnel syndrome and shoulder rotator cuff injuries. After joint disorders mainly affecting the upper limbs and neck, deterioration of visual acuity is the second most commonly reported condition. A literature review can identify risk factors, particularly arm abduction greater than 30°, repeated isometric maneuvers without compensatory rest, the level of force applied to the probe, abdominal scanning approaches, examination times longer than 25 minutes, and more than 100 sonographic examinations per month. The ergonomics of the operator's workstation and posture are essential to prevent these disorders. Machine, probe, chair, and examination bed designs are already subject to industrial consensus, but sonographers are responsible for configuring their ideal workstations to preserve their professional and physical potential. Therefore, this article proposes rules of good practice and illustrates recommended positions and those to avoid.

Reference ranges and distribution of placental volume by 3-dimensional virtual organ computer-aided analysis between 11 weeks and 13 weeks 6 days.

OBJECTIVES: The purpose of this study was to determine the feasibility, reproducibility, and distribution of placental volume measurements according to the crown-rump length between 11 weeks and 13 weeks 6 days. METHODS: Images were acquired in 128 pregnancies followed in Burgundy during first-trimester screening sonography using an abdominal 3-dimensional transducer. The placental volume was then calculated by the virtual organ computer-aided analysis method with a rotation angle of 30° by a single operator. RESULTS: Placental volumes ranged from 33.3 to 107.6 cm(3) with a mean ± SD of 62.3 ± 14.8 cm(3); the 5th and 10th percentiles were 38.0 and 44.20 cm(3), respectively, whereas the 90th and 95th percentiles were 80.25 and 86.68 cm(3). An exponential relationship was found between placental volume and crown-rump length: ln placental volume = 0.018 × crown-rump length + 2.93425; ln SD = 0.15; r(2) = 0.58. Finally, the mean placental quotient, defined as the ratio of placental volume to crown-rump length, was 1 ± 0.1 cm(3)/mm; the respective percentile values were 0.74, 0.81, 1.18, and 1.29 cm(3)/mm. No associations were found between parity or smoking and the placental quotient or between obesity and the placental quotient. Intraobserver reproducibility was good, with a mean difference of 0.2 cm(3). CONCLUSIONS: Measurement of placental volume between 11 weeks and 13 weeks 6 days is reliable and reproducible and correlates strongly with crown-rump length.