**3. History and general principles of fetal surgery**

In 1963 first fetal intervention was performed (**Table 1**), the first fetal transfusion was reported by Liley. He used Tuohy needle (size 16-G) into the fetal peritoneal space. He injected a contrast material into the amniotic cavity to localize the fetal abdomen and the swallowed contrast opacify the fetal bowel. In the 1970s, endoscopy was used for direct visualization of the fetus, and the first fetal blood sampling or biopsy tissue was reported, however because of the limited technical skill, the therapeutic uses were not applicable [1, 2]. After that, with more use of ultrasound as non-invasive diagnostic tool, the use of diagnostic fetoscopy was replaced with percutaneous needle-based techniques under ultrasound guidance. In the 1980s open fetal surgery was started (direct exposure of the fetus by maternal laparotomy and hysterostomy), then open fetal surgery was replaced with a less invasive fetoscopy, where video camera was inserted inside the uterus under ultrasound guides. At first, fetoscopy was performed in amniotic fluid medium, using a single port to enter the uterine cavity and with a side way working channel. However, amniotic fluid medium poses many limitations for many fetal surgeries especially that require dissection and suture. Low quality images in the fluid medium, and any bleeding will prevent an adequate imaging, and it can end the procedure. Moreover, the "fluctuation" of the fetus during the intervention prevent maintenance of the ideal accessible position. In 2010 Kohl et al. use low insufflation pressure carbon dioxide of amniotic cavity which was left with some amount of amniotic fluid [3–6].


#### **Table 1.**

*Time scales for important fetal surgeries.*
