A port is made up of two parts: a flexible plastic tube / catheter of 2 to 3 mm in diameter, which is positioned in the venous blood vessel system, and a port chamber made from polyurethane or titanium, which is inserted under the skin in the chest or arm area. The name port comes from the Latin word “porta” (door, gate, entrance).

Ports have several advantages. Firstly they are implanted fully into the patient’s body and therefore generally undetectable when not in use. Secondly they can remain in the patient’s body for a long time, up to several years. Ports are generally implanted for long-term treatments such as chemotherapy or parenteral nutrition. Blood samples can also be taken from ports. Special ports are also available for high-pressure injections (up to 5 ml/s and up to a pressure of 300 psi) of contrast medium used in CT or MRI scans (high-pressure ports).

Figure 1: Schematic diagram and X-ray image of a port system. The port system is made up of a port reservoir / port chamber and the port catheter. In this case, the port reservoir has been implanted in the area of the right rib cage and the access to the vein system is via the internal jugular vein (Vena jugularis interna). The tip of the port system is positioned in the cross-over of the superior vena cava in the right atrium of the heart. The associated X-ray image shows the port reservoir in the right rib cage and part of the catheter tube.

Ports are sited under local anaesthetic and using ultrasound and X-ray guidance. The internal jugular vein or subclavian vein is punctured using a cannula and the catheter is then fed into the vascular system using a guide wire (this is known as the Seldinger technique). The end of the catheter is then connected to the port chamber already inserted in the chest area and secured into place. Both the port catheter and the port chamber lie under the skin and are only detectable externally by a slight swelling of the skin. The port chamber can be punctured through the skin as often as necessary from the outside using a special port needle.

Ports should be regularly flushed with 0.9% saline solution. A port needle can remain in place for up to seven days. It should be changed under sterile conditions in order to prevent a port infection. If a port is not used for some time, it should be flushed with 1,000 IU of heparin in 10 ml of saline solution in order to avoid the formation of blood clots. With suitable care, ports can remain in place for several years.

The combination of ultrasound-guided venepuncture and fluoroscopy-guided (with X-rays) placement of the port catheter means that the potential risks can be reduced to a very low level. Overall, this method is the safest for implanting central venous catheters and ports. Potential risks include bleeding and bruising, the missed puncture of the jugular artery or subclavian artery, infection or the formation of an abscess, thrombosis of the vein or catheter, the introduction of air into the pleural fissure (pneumothorax) or injury to neighbouring organs.

Figure 2: The figure shows the sutured skin incisions in the neck (vein puncture site) and on the chest (position of the port capsule) immediately after the outpatient procedure.

Figure 3: After just a few weeks, the incisions in the skin on the neck and chest have healed to form unnoticeable scars. Depending on the patient’s body habitus, the port capsule and port catheter may be only noticeable as a small swelling under the skin. The penetration of the port capsule with a port needle is generally not painful. After removing the needle from the injection site, a small bruise can form which usually disappears after a few days.

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Minimally Invasive Tumour Therapy (MITT)
Charité Campus Virchow-Klinikum (CVK)
Department of Radiology
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13353 Berlin

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