[Amniocentesis under permanent ultrasonic control--advantages of a special procedure]

Advocates of the so-called "free hand technique" in amniocentesis argue against permanent sonographic control as follows: "Free hand technique" is the only method enabling vertical guiding of the puncture needle between abdominal wall and amniotic cavity, and hence to cover the shortest distance with the lowest risk of traumatisation. "Free hand technique" is the only method permitting sensitive guiding of the needle in amniocentesis, since the puncturing doctor can use both hands without requiring one hand for sonographic examination. Amniocentesis under permanent sonographic control is claimed to raise serious problems in guaranteeing the necessary sterility. The authors present a modification of the puncture method with permanent sonographic control. This does away with all of the above arguments against permanent sonographic control, whereas all of its obvious advantages are retained (greater safety, less risk of injury). The method employs a fixation scaffolding and an aiming groove for routine sector scanning (Figures 1 and 2). The entire system is covered in a sterile manner by a pasted-on foil sheeting after having introduced the sonographic contact gel. The only contact medium for the skin is a disinfecting agent enabling satisfactory imaging (Figure 4). This method offers the following advantages over the methods using conventional puncture soundheads: Better possibility of disinfection. No rigid guiding of needle, and hence correction can be effected even during puncture. Adjacent levels can be observed by free displacement of scanner and needle. Modifiable puncture angle in respect of skin and uterus. The fixation scaffolding does away with the need for an assistant, and enables tremor-free fixation of the scanner during puncture.(ABSTRACT TRUNCATED AT 250 WORDS)