Arteriovenous malformations

Arterio-venous malformation is a vascular lesion made up of small vessels linking the arterial side of the circulation to the venous side. These may be widespread, diffuse lesions or they may be localized, focal lesions. The overlying skin may be involved and in these cases, there is a pinkish hue. As with all other vascular malformations, arterio-venous malformations are always present at birth although they may only become evident at a later stage. Slow steady expansion will be seen and the supplying arteries and draining veins will also increase in size as the malformation enlarges. These lesions are fairly firm to palpation and are frequently surrounded by large dilated vessels. They usually do not expand when in a dependant position.

Laser treatment

Laser treatment has a limited role. A laser can be used to reduce the redness of the skin overlying an arterio-venous malformation. A pulse dye laser is used for this.

Embolization

The intentional closing of blood vessels - can be used in the treatment of many conditions. Sometimes embolization can be the sole form of treatment, but it can also be used in conjunction with surgery. An embolizing agent - a material used to seal the blood vessel - is injected through the catheter. There are a variety of embolic agents used depending on the specific requirements. They include: small plastic particles, glue, or foam; each has a specific use depending on the vascular disorder being treated
Embolization is a procedure whereby, through an artery, a catheter is advanced until it reaches the site of the disease. At this point, a substance or particles are placed within the nidus of the AVM until the degree of shunting is reduced or it has been eliminated. Using percutaneous (across skin) access, substances can also be used to block the venous system of the AVM. This is usually followed within 24 – 48 hours by surgical resection of the nidus, unless the treatment plan is directed in utilizing embolization as a sole treatment modality

Surgery

Treatment will usually consist of embolization, followed by surgical excision.
The excision is targeted against the nidus of the malformation and follows the same principals regarding the extent of resection as mentioned in the venous malformations chapter. Many times a reconstruction of the defect is necessary. With the aid of our plastic and reconstructive surgeons we are able to utilize local flaps or free vascularized flaps to reconstruct the defect.

There is a dilemma. If the AVM is extensive, it is important to resect only enough tissue to prevent a recurrence if this is possible.
Resecting too much tissue, especially in the head and neck region will be too disfiguring. It is therefore important to avoid this and err on the side of being conservative.

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