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Definitions
Complex ovarian cysts: any ovarian cyst with morphology other than simple.
Ectopic pregnancy: pregnancy located anywhere outside the normal endometrial location.
Extraembryonic coelom: portion of an early pregnancy located between the amniotic cavity but still within the chorion.
Multifetal pregnancy reduction: procedure utilized to reduce the number of fetuses in a given pregnancy to a lower, more desirable number.
Peritoneal inclusion cyst: usually large, multiloculated fluid and pelvic adhesions collection.
Simple ovarian cysts: ovarian cysts that are anechoic, thin, and smooth walled, without septation or wall irregularities.
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Previously, ultrasound-guided procedures were essentially exclusively performed abdominally. With the recent improvement in vaginal ultrasound equipment and technique, vaginal ultrasonographically guided puncture procedures have replaced abdominally guided puncture in many cases. Certainly, procedures such as amniocentesis will always be performed abdominally, but marked changes in assisted reproductive technologies, specifically in vitro fertilization and human egg retrieval, have paved the way for vaginally guided techniques. The aim of this chapter is to describe the various vaginally guided puncture procedures, both those being presently performed and those being studied experimentally, and the experience gained thus far.
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Ever since Smith and Bartrum1 performed percutaneous aspiration of intraabdominal abscesses in 1974 and Gerzof et al used an abdominal catheter placed sonographically to drain purulent pelvic collections,2,3 ultrasound-guided puncture procedures have been used to achieve both diagnostic and therapeutic goals. The advantages of these procedures over traditional surgical means are multiple: ease of technical mastery, accurate needle placement, rare injury to adjacent organs, portability, low cost, speed of administration, and, probably above all, patient satisfaction and comfort. Possible risks, although quite rare, include bleeding, infection, inadvertent puncture of organs, and, in the case of multifetal reductions, miscarriage.
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Puncture procedures necessarily traverse three-dimensional space, not only the two-dimensional view of an ultrasound machine screen. This third dimension, because of the properties of ultrasound, is thinnest at the focal range of the probe and is inversely proportional to the operating frequency of the transducer crystal. This concept is called the slice thickness artifact and means that the operator must take the third dimension of the image into account: At times the tip of the needle used for puncture procedures appears to be within the structure at which it is aimed, but in reality it is in front of or behind the structure imaged.
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When puncture procedures are performed abdominally, 1 of 2 techniques is employed: needle guide or free hand. Often, an operator uses a transabdominal needle guide when a needle has to be directed into a body part. With increasing experience, the free-hand approach has been successfully practiced, with the ease of handling the needle and keeping it in the scanning plane. The limitation of this technique is that occasionally the transverse section of the needle, excluding the tip, is what is ...