What is endovascular neurosurgery?
Endovascular Neurosurgery is a subspecialty of neurosurgery in which neurosurgical procedures are performed within blood vessels under fluoroscopic guidance.
Endovascular neurosurgery, also known as interventional neuroradiology, utilizes a thin catheter to perform diagnostic and surgical procedures within blood vessels and spinal vertebrae, while using x-ray guidance.
It is somewhat similar to the treatment carried out in the heart by cardiologists, such as angioplasty or stent placement. In these procedures, very thin catheters or wires are placed through blood vessels in groin and navigated in the blood vessels to the site of the abnormal vessels.
Endovascular surgery is used to treat a variety of cerebrovascular diseases (disorders of the blood vessels of the head and neck) including stroke, aneurysms, tumors, arteriovenous malformations and dural arteriovenous fistulas. Endovascular procedures are performed in the angiographic suite (located in the x-ray department), rather than the operating room.
A team approach involving neurosurgery, neuroradiology, and neurology combined with the use of the highest quality angiographic equipment is essential for optimal results. Endovascular procedures are often used to visualize blood vessels through cerebral angiography, to open clogged or narrowed arteries, to stabilize weak and bulging vessels or to seal specific blood vessels before surgery to minimize bleeding during the operation.
Who performs endovascular neurosurgery?Endovascular procedure is performed by a neurosurgeon or neuroradiologist or interventional neurologist who has specialized training in endovascular surgery. Ask your doctor about their training, especially if your case is complex. As each patient and aneurysm differs, it’s important to seek treatment at a medical center that offers the full range of options—clipping, coiling, and bypass.
Preparatory requirements for a fellowship in INR/NIS include successful completion of a residency in Neurosurgery, Radiology, or Neurology and additional training depending on the given field. Neurologists must complete additional fellowship training in neurovascular diseases/vascular neurology, stroke neurology, or neurocritical care as well as gain experience in neuroangiography in order to qualify to train in a Neurointerventional fellowship. Radiologists usually complete a fellowship in diagnostic neuroradiology prior to a Neurointerventional fellowship. Neurosurgeons must gain experience in neuroangiography prior to a Neurointerventional fellowship.
At present through out world all three subspecialty people (Neurosurgeons, Neuroradiologists, Neurologists) are performing these procedures.
What are the diseases treated by endovascular method?
Endovascular techniques can treat a variety of intracranial disorders. Many of them are curative. Tumour embolization is done for preoperative devascularisation to prevent bleeding during surgery. Few of the endovascular procedures are done with palliative intention.
- Arteriovenous malformations
- Carotid cavernous sinus fistulae
- Dural Fistulas
- Vascular tumors
- Vasospastic arteries(vasospasms)
- Intracranial arterial stenosis for angioplasty and stenting
- Cerebral revascularization after clotting (acute ischemic stroke)
- Carotid diseases (Extracranial atherosclerosis)
- Extracranial (head and neck) and paraspinal vascular malformations
- Intracranial atherosclerosis
- Juvenile nasopharyngeal tumor
- Nose bleeds
- Head and neck tumors
- Spinal vascular malformations
- Traumatic vascular lesions
- Vertebral body tumors
- Vertebral body compression fractures
How is endovascular procedure performed?
Example of aneurysm coiling procedure is described below………..
Endovascular procedures are usually performed in the special procedures room or angiography suite in the radiology department. The procedure has six steps and generally takes 2 to 4 hours.
prepare the patient: You will lie on your back on the x-ray table and be given anesthesia. The type of anesthesia used varies: conscious sedation for those in good condition or general anesthesia for others. Anti-clotting medication (heparin) is injected throughout the procedure to prevent blood clots from forming. Your head is positioned so that it will not move during the procedure.
Figure 2. Coiling is performed during an angiogram. A catheter is inserted into the femoral artery in the groin. It is then guided through the arterial system to the arteries in the brain.
Insert the catheter: After the inner thigh and groin area are shaved and cleansed, a local numbing agent is given to minimize discomfort as the skin incision is made. The femoral artery is located and a hollow needle is inserted into the artery. Next, a long tube made of flexible plastic called a catheter, is passed through the needle to enter the bloodstream. A special dye, called a contrast agent, is injected into the bloodstream through the catheter. The dye makes the blood vessels visible on the x-ray monitor (fluoroscope). Watching the monitor while injecting dye, the doctor carefully guides the catheter from the femoral artery in the leg, up the aorta, past the heart, and to one of four arteries in the neck that lead to the brain (Fig. 2). You may feel brief pain when the catheter is inserted, but most catheter manipulation is painless.
Figure 3. Angiogram shows a catheter in the internal carotid artery. A flush of dye shows blood filling an aneurysm.
locate the aneurysm: When the catheter is placed correctly, the doctor injects the contrast agent while x-ray pictures are taken (Fig. 3). You may feel a hot, flush that lasts 5 to 20 seconds. This procedure may be repeated several times until the doctor can view all necessary arteries and take measurements of the aneurysm, especially its neck.
Figure 4. A microcatheter is inserted into the aneurysm to deliver coils into the dome.
Insert the coils: A second smaller catheter, about the size of a string of spaghetti, is advanced through the first catheter. This microcatheter travels through the arteries and into the aneurysm itself. Next, small platinum coils are advanced through the catheter until they emerge inside the aneurysm (Fig. 4). Once again, contrast agent is injected to allow the doctor to see the coils on the fluoroscope monitor. If the position is good, the doctor releases the coil from a guide wire. Coils are inserted in this manner, one after another, until the aneurysm is packed (Fig. 5). Sometimes an inflatable balloon is used to guide coils into the aneurysm.
Figure 6. A stent is used for aneurysms with a wide neck to help hold the coils in place. Arrow shows bloodflow through artery.
Check the coils: By injecting contrast agent, the doctor inspects the coils to ensure that blood is no longer flowing into the aneurysm (Fig. 7). This technique also verifies that the coils are inside the aneurysm and not narrowing the main artery.
Figure 7. Angiogram shows coils filling the aneurysm.
Remove the catheter : Once the coils have been placed, the catheter is removed. Pressure is applied to the groin area for about 10 to 15 minutes so that the artery won't bleed. A bandage is tightly applied to the incision.
What are the advantages of endovascular procedure?Advantages are
1. No craniotomy, only a small groin needle puncture is needed.
2. Possibility of performing under local anaesthesia.
3. Faster recovery
4. Quicker return to work and activities
5. Reduced blood loss
6. Less pain
7. No brain retraction
8. Decreased postoperative narcotics
9. Shorter hospital stay
What are the complications of endovascular procedures?Kindly see respective disease section for complications of endovascular procedures for a particular disease.
In general complications of endovascular disease are…
1. Groin hematoma
2. Groin puncture site infection
3. Thrombo-embolic complications,
4. Vessel rupture
5. Contrast nephropathy
6. Arteriovenous fistula at the needle puncture site
8. Recurrence of diseases.