The described advancements in surgical possibilities would not be possible without the advancement of technology. The ultrasound, the fetoscope, and also radiofrequency ablation are intricate and imperative aspects of the aforementioned medical procedures. The following section will explain how each of these technologies work, as to provide a more thorough understanding of the complexity and the diversity of foetal surgeries.
Ultrasonography is a medical imaging technique that utilizes high frequency sound waves and their reflected echo waves. Millions of waves are dispersed each second, and as the waves hit a boundary, for example between soft tissue and bone or fluid and soft tissue, they are reflected back to the probe. Some waves continue on and reflect off the next boundary that they hit. As the probe receives the signals form the reflected waves, it can calculate the distance travelled by measuring the elapsed time (distance = velocity/time). As different waves return after travellin different distances, the ultrasound machine can compile a two dimensional image.
The Ultrasonography machine is made up of a transducer probe, which sends and receives the sounds waves, and this is connected the transducer pulse control. The transducer pulse control regulates the amplitude of the sounds waves, and varies them between one and five megahertz. The central processing unit is responsible for collecting the received data, compiling an image, and displaying the image on a screen.
The transducer probe uses quartz crystals, called piezoelectric crystals, to generate the piezoelectric effect. An electric current is applied to the crystals, which causes them to change shape. As the crystals vibrate, or change shape, they produce the sound waves. Conversely, as the echo waves return they vibrate the crystals, which send electrical currents back to the central computer.
Recently, three-dimensional ultrasonography imaging had become possible. The probes of these machines are moved across the body and the central computer compiles the numerous two-dimensional images to create a three dimensional image. This allows for precise monitoring of the foetus for abnormalities and blood flow can also be visualized in the foetus utalizing these images.
The possible dangers of ultrasounds have often been questioned, but research shows that no serious harm can arise due to ultrasonography. The two most persistent side effects include the development of heat inside the foetus, which is generated by the energy carried in the sound waves, and the formation of bubbles as dissolved gases are driven out of solution by the emitted heat. For theses reasons, ultrasounds are only used when necessary.
A fetoscope is a visual tool used by surgeons that allow them to see inside the uterus during surgery by making a tiny incision, dramatically reducing the degree of invasiveness of the surgery. Fetoscopes have drastically improved foetal surgeries by decreasing the number of risks posed to both the mother and the child.
Fetoscopes contain optical fibres that carry light to the area that must be visualized. It is imperative that enough light be transmitted to put the entire field in clear view and allows the surgeons effectively see their working area. The larger the fetoscope, the more cables it contains and therefore the brighter and clearer the image will appear. Fetoscopes range in radius from 13.5 to 6 millimetres. Associated with increased light intensity is the increased intensity of heat. For this reason, surgeons must be very careful not to burn patients while using the fetoscope. A video camera is also attached to the end of the fetoscope, and the entire system is attached to a video monitor, which receives the images.
Necessary sterilization procedures must be used before using the fetoscope. Also, a fetoscope heater is used to heat the apparatus to body temperature. This prevents the machine from fogging.
Radiofrequency Ablation (RFA)
This revolutionary procedure allows for the elimination of cancerous cells with minimal invasiveness. RFA uses extreme temperatures (up to 100 degrees Celsius) to kill caner cells. It has been effectively used in situations when chemotherapy and radiation proved ineffective and requires brief intravenous sedation.
During the procedure, a CT scan or and ultrasonogram are used for guidance as a needle is inserted inside the tumour. The needle contains an electrode which emits high frequency radio waves that generate the intense heat. The procedure occurs over a period of between forty-five and ninety minutes and requires an incision no bigger than a band-aid.
Currently, RFA has been used to treat Sacrococcygeal Teratoma, breast cancer, and also kinder, lung, and bone cancer. Its effectiveness in treating metastatic bone disease is currently being tested.
Click here to see a live RFA preformed by surgeons at the University of Cinncinnati.
A brief summary and demonstration of an RFA procedure can be seen by clicking here.
The Anatomy and Development of the Foetus
Medical Conditions Affecting the Foetus from initial diagnosis to treatment:
Congenital Diaphragmatic Hernia (CDH)
Congenital Cystic Adenomatoid Malformation of the Lung (CCAM)
Sacrococcygeal Teratoma (SCT)
Urinary Tract Obstruction
Radiofrequency Ablation (RFA)
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