The Penn State Stroke Center provides several lifesaving services for vascular malformations and brain disorders. 

What is a vascular malformation?

Vascular malformations are abnormal collections of blood vessels. They are considered neurological problems when they occur in the brain or spinal cord. 

We treat the four major types of vascular malformations of the brain and spinal cord:

We also treat the following brain disorders:

Arteriovenous malformations (AVM)

Arteriovenous malformations, or AVMs (also referred to as high flow AVMs), consist of an abnormal network of blood vessels in the brain or spine. AVMs are thought to arise during fetal (baby) development. They occur in less than 1 percent of the population. 

AVMs can cause bleeding (most common), seizures and problems with nerve, spinal cord or brain function. Bleeding from AVMs usually takes the form of a hemorrhage (known as intraventricular, intraparenchymal or subarachnoid hemorrhage).

If your doctor thinks you may have an AVM because of your medical history or physical exam, he or she will recommend imaging tests. A CT or MRI scan (which take pictures of the inside of the body) will usually show the exact location of a lesion. 

Your doctor will then order an angiogram (X-ray of the blood vessels) to give a more detailed picture of the AVM. An angiogram is essential to planning any treatment for the AVM.

Treatments for arteriovenous malformations

Many AVMs require more than one form of treatment. Penn State Health experts use a multidisciplinary approach to the evaluation and treatment of patients with these lesions. Complex cases are reviewed at a multidisciplinary conference with professionals from all major treatment areas. 

After careful consideration, your care team will develop an individualized treatment plan. They will often use a combination of microsurgery, endovascular embolization and stereotactic radiosurgery to achieve a complete cure.


Microsurgery uses traditional surgical techniques under high magnification and sometimes with computerized guidance to remove the AVM. One of the major advantages of microsurgery is that it can result in an immediate cure. However, some lesions may be too large, too deep or located in too important of an area of the brain for safe microsurgical excision. In such cases, other treatments may be necessary.

Endovascular embolization

With endovascular embolization (or endovascular surgery), treatment is performed from within the affected blood vessel. Your surgeon will guide a specially designed microcatheter (small, thin tubes) using an angiogram (X-ray of the blood vessels) right up and into the AVM itself. The lesion is then sealed from the inside with either particles or glue. This process is called embolization. 

Some forms of endovascular treatment are investigational and require special consent. Although very effective in reducing the size of an AVM or removing AVMs that are very small, endovascular embolization is rarely able to completely destroy large AVMs. Endovascular therapy, therefore, is usually combined with either microsurgery or stereotactic radiosurgery to give the greatest chance of a cure.

Stereotactic radiosurgery

Stereotactic radiosurgery involves the delivery of a highly-focused beam of radiation to the AVM. The two most common forms of radiosurgery are linear accelerator-based radiosurgery (also known as LINAC or photon knife) and gamma ray-based radiosurgery (gamma knife). Radiosurgery may be less risky when compared to microsurgery for patients with AVMs that are deep or located in important brain areas. However, the larger the AVM, the less successful radiosurgery will be. Therefore, radiosurgery is especially appropriate for small lesions that are located in or near critical brain areas or are very deep.

Cavernous angioma

A cavernous angioma (also known as a cavernous malformation or cavernoma) is a type of AVM. These lesions consist of a collection of blood vessels with slow blood flow. The malformations are not visible on a conventional angiogram (X-ray of the blood vessels). For this reason, cavernous angiomas are often referred to as angiographically occult vascular malformations (AOVM). 

AOVMs may cause seizures and frequently bleed or leak blood. Severe or frequent bleeding may lead to the development of a neurological problem. 

Treatment for cavernous angioma

Microsurgery is the treatment of choice for lesions that are causing symptoms and more easily accessible. Removal of these cavernous angioma during surgery eliminates the risk of bleeding. 

In the case of epilepsy, surgery may cure or at least reduce the severity of seizures. Since cavernous angiomas are not visible on an angiogram, endovascular surgery is not possible. 

Stereotactic radiosurgery (delivery of a highly focused beam of radiation to the AVM) may help in the treatment of some deep or inaccessible lesions. 

Specialists at Penn State Health have considerable experience and special training in the treatment of AOVMs of the brain and spinal cord. We are able to safely remove many challenging AOVMs that might previously have been left untreated. We use specialized skull-base microsurgical techniques and a computerized image guidance system.

Carotid cavernous fistula

Carotid cavernous fistula is a type of AVM that occurs between the internal or external carotid arteries and the cavernous sinus.

Dural arteriovenous fistulas

Unlike AVMs and cavernous angiomas, which are usually congenital (arise during baby development), dural arteriovenous fistula (DAVF) develop later in life. 

These lesions consist of abnormal connections between arteries outside of the brain, such as those that supply the scalp or face and nearby veins with blood. Patients with DAVF will often seek medical attention because they hear a “wooshing” sound that follows their heart beat.

Occasionally, DAVF can bleed, causing a stroke. DAVF may be suspected on MRI or CT scans. However, an angiogram (X-ray of the blood vessels) is usually required to confirm the diagnosis. Depending on the severity of symptoms and the exact configuration of the DAVF on an angiogram, the lesion may or may not need to be treated. 

Treatments for dural arteriovenous fistulas

Similar to AVMs, DAVF may be treated with Onyx (endovascular glue embolization), microsurgerystereotactic radiosurgery or a combination. At Penn State Health, our physicians have experience and training in all major forms of treatment for DAVF.