New visualization techniques for in utero surgery: amnioscopy with a three-dimensional head-mounted display and a computer-controlled endoscope.

Abstract

Endoscopic fetal surgery may reduce preterm labor associated with open hysterotomy but is partially limited by current visualization technology. We investigated a three-dimensional (3D) imaging system coupled to a head-mounted display (3D-HMD) and also employed a computer-controlled zoom endoscope for noninsufflated amnioscopy. Pregnant sheep were prepared in aseptic fashion for general anesthesia. Uterine access was obtained following maternal laparoscopy. A 10-mm zoom endoscope (Vista Medical Technologies, Carlsbad, CA) was used to examine the fetus and uterine contents. Fetal limbs were exteriorized for microsurgery. A new system (Vista Medical Technologies) was attached to an operative microscope, permitting projection of a 3D image via an HMD. The fetus and umbilical cord were inspected using the zoom endoscope, which changes the depth of focus under computer control. Basic manipulations of the fetus and cord were easily completed. Real-time 3D fetal imaging was accomplished. The added depth perception enabled detailed fetal and placental examination, fostering manipulation of the fetus and cord. The HMD was adjusted to fit several surgeons, permitting a natural operative posture. This unit has the capacity to display any video, CT, MR, or ultrasound image as a picture-in-picture. The success of minimally invasive fetal surgery is in part dependent on the development of video technologies capable of providing both magnification and optimal resolution. The zoom endoscope affords excellent visibility of multiple surgical targets without instrument repositioning. A 3D HMD system such as this provides greater anatomic detail and an appreciation of fetal movements that may make intrauterine procedures more feasible.