Ultrasound is an integral part of prenatal interventions. Doppler studies and 3-dimensional ultrasound (3DUS) are frequently used to determine whether fetal surgery is required. The operator’s experience remains crucial for reducing procedure-related morbidity. Real-time 3DUS (or 4DUS) can simultaneously display the needle tip in three orthogonal planes, providing reassurance that no fetal parts are in the path. In experienced hands, 4DUS guidance may not be more effective than B-mode, but its value for less-experienced operators remains to be determined. Recent developments in needle, shunt, and video endoscopic technologies may compliment the use of image-guided in utero procedures. Future developments of higher-dimensional transducers and image software may improve the utility of ultrasound for invasive obstetric interventions.

BackgroundTwin reversed arterial perfusion (TRAP) sequence consists of acardiac twin (A) paradoxically perfused by pump twin (P) through an umbilical artery (UA). We proposed characterization of acardiac twins with intrafetal vascular pattern (IVP), and assessed its correlation with morphology and UA Doppler indices.MethodsWe prospectively evaluated 21 cases of TRAP sequence. Morphology (acardia vs hemicardia) and IVP (simple vs complex) of acardiac twins were characterized with ultrasound and color Doppler. Twins weight ratio (A/P Wt) and UA Doppler indices of acardiac and pump twins including (1) difference of systolic/diastolic ratio (UA ∆S/D), (2) difference of resistance index (UA ∆RI), and (3) ratio of pulsatility index (UA PI A/P) were calculated.ResultsThe median (min, max) gestational age at diagnosis was 18 (11, 27) weeks. Acardia (n = 14) were associated with simple IVP (n = 16) (P < .05). After exclusion of acardia with complex IVP (n = 1), the A/P Wt, UA ∆S/D, UA ∆RI, and UA PI A/P of acardia with simple IVP (n = 13), hemicardia with simple IVP (n = 3), and hemicardia with complex IVP (n = 4) were not significantly different (P > .05).ConclusionsMost of acardiac twins were acardia with simple IVP. Morphology and IVP of acardiac twins were not associated with UA Doppler indices.

Aim To assess the impact of laser power and time on interstitial ablation generated by neodymium‐doped yttrium aluminium garnet (Nd:YAG) and diode laser in the human placental model. Methods The experiment was carried out in a simulation model of interstitial laser ablation on ex‐vivo placental tissue. One‐hundred and forty‐four pieces of fresh placentae were interstitially ablated with Nd:YAG or diode laser at various power (15, 20, 25, 30 W)‐time (5, 10, 15 s) combinations. The ablation tissues were evaluated using both sonographic and histopathologic measurements. Results Laser generator, power, and time significantly affected the ablation size (p < 0.001). The coagulation zone continuously increased with extending time at the power of 15, 20, and 25 W. When adjusting to the power of 30 W, increased time from 10 to 15 s did not induce the larger coagulation diameter. The maximal diameter was obtained at the laser power of 20 W for 15 s. The ablation from the diode laser was greater than that from Nd:YAG laser. The sonographic evaluation overestimated the ablation size by an average of 24%. Conclusion Diode laser destroys greater tissue than Nd:YAG laser. Different power settings of interstitial laser ablation produce diverse patterns of correlation between laser time and coagulation size.

Objectives To develop a simulation model and assess the learning curve of fetal shunting. Methods Three staff and three trainees performed fetal shunting on a model using the fetal bladder stent. The model was evaluated according to various sources of validity evidence. The number of procedures to reach competency was determined by the learning curve‐cumulative summation (LC‐CUSUM) and CUSUM analysis. The learning and control phases were defined as the periods before and after passing the level of competency, respectively. Results The model was validated to be constructive in the educational process. A total of 600 procedures were carried out with an overall success rate of 94.2% and no significant difference between staff and trainees. The average number of procedures to reach competency was 47. Total procedural time decreased after passing the level of competency. Although the trainees required a longer procedural time in the learning phase than the staff did, there was no significant between‐group difference in the control phase. Conclusions Using this model, the estimated number of procedures to achieve competency was 47, as substantiated by the increased procedural success and reduced procedural time in the control phase. Training on this simulation model may improve technical performance.

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