Paroxysmal headache, which is one of the manifestations of cerebral arteriovenous malformation, but not necessarily cerebral arteriovenous malformation, requires examination to determine this.
Cerebral arteriovenous malformation is one of the cerebrovascular malformations. Cerebrovascular malformation is a type of disease in which the number and structure of local blood vessels in the brain are abnormal due to abnormal development of cerebral blood vessels and affect the normal cerebral blood flow. They include arteriovenous malformations, cavernous hemangiomas, capillary dilation, and venous malformations. Cerebral AVMs are caused by abnormal differentiation of the primitive germinal development of cerebral vessels in early embryonic life. It commonly develops at the age of 16-35 years (mean 25.7 years), with an incidence of approximately 0.35%-1.1%. It is more common in males than females and can occur at any site, but is significantly more common supratentorially than infratentorially. In terms of size, AVMs are classified as small (<2cm in diameter), medium (2-4cm in diameter), large (4-6cm in diameter), and extra large (>6cm). This has greater significance in the selection of treatment and in determining healing.
Treatment methods of cerebral AVM
1.Microsurgical resection: Microscopic neurosurgery has developed considerably in the past 20 years, which has significantly improved the surgical cure rate of AVM. For small and medium-sized AVMs with superficial location and non-important functional areas, surgery is relatively easy, with good postoperative results and low complications and mortality. However, surgery is traumatic after all, and still has a certain disability rate and mortality rate. For AVM with deep brain, important functional area and huge volume, surgery is still difficult and dangerous, and the disability rate can be as high as 48%, so surgery should be taken with caution.
2, intravascular embolization therapy: embolization therapy has a history of nearly fifty years, and its indications are.
(1) For AVM of single or few blood supply arteries, especially for patients with recent bleeding, endovascular embolization can achieve the purpose of micro-invasive, less painful and rapid therapeutic effect.
(2) For AVM in large and functional areas, embolization can reduce its volume and improve hemodynamic distribution for microsurgical resection and stereotactic radiosurgery treatment.
(3) Head Gamma Knife: Head Gamma Knife has unique superiority and has become an important method for the treatment of AVM, and is one of the main treatment objects of head Gamma Knife. The smaller the volume of AVM, the higher the rate of occlusion in two years. overall speaking, the rate of complete occlusion in one year after gamma knife treatment of AVM is close to 50%, the rate of complete occlusion in two years reaches 80%, the rate of complete occlusion in three years reaches more than 90%, the rate of epilepsy cessation or remission reaches more than 50%, the rate of headache disappearance or improvement reaches 75%, and the rate of observation period re Bleeding rate of only 3-4%, safe and reliable.
The mechanism of head gamma knife treatment of brain AVM
After the head gamma knife irradiation malformed vascular mass, through a series of biological effects of blood vessels, the malformed blood vessels gradually occlusion and achieve the purpose of treatment. The pathological change is that gamma radiation causes damage to the endothelial cells of the malformed vessels, which then causes repairing thickening of the connective tissue of the vessel wall, thickening of the vessel wall and gradual reduction of the vessel lumen, leading to the closure of the final malformed vessels.
The process of aberrant vessel occlusion after gamma knife treatment has three stages.
1, vascular endothelial or subendothelial injury: mainly manifested as rupture, separation or detachment of vascular endothelial cells from the vessel wall.
2, endothelial smooth muscle cell proliferation: all or most of the smooth muscle cells in the lumen of the vessel proliferate, causing centripetal or eccentric stenosis of the lumen.
3, cell degeneration and stromal increase: most of the malformed vessels are occluded, mainly by cell degeneration with hyaline-like changes.
The indications for head gamma knife treatment of AVM are.
1, small and medium-sized, located in important functional brain areas and deep brain AVM.
2, craniotomy failure and residual AVM after endovascular embolization treatment.
3, Small and medium-sized AVMs after three months of hemorrhage.
4.The elderly and frail or those who cannot tolerate general anesthesia or craniotomy due to serious diseases of other important organs of the body.
5.Some large AVM, AVM that cannot be operated for various reasons or AVM that is still large in volume after repeated embolization, can be considered for head gamma knife fractionation or division treatment.