Giant Aneurysms
Giant Cerebral or Intracranial Aneurysms are those, which are 2.5cm (25mm or 0.98 in) or larger in diameter. Thought to be rather infrequent, some sources indicate that these lesions represent 5 to 8% of all Intracranial Aneurysms. The most common location, accounting for 60%, of Giant Aneurysm is the Internal Carotid artery. The Anterior Communicating artery and the Middle Cerebral artery account for another 10% each and 15% occur at the top of the Basilar artery and another 5% crop up on the Vertebral artery.
Long associated with a high mortality rate, when compared to smaller Aneurysms, modern techniques and procedure have greatly improved the safety of treatment and likelihood of a successful outcome. One facility has reported that 89% of its patients receiving treatment for Giant Aneurysms have excellent or good results.
Surprisingly, despite the greater size, Subarachnoid Hemorrhage is the presenting symptom in only 25-26% of patients while 70-75% present with Mass Effect such as visual disorders. Another 2-5% suffers Thrombosis and stroke due to blood clot formation within the Aneurysm.
Treatment of these large Aneurysms present unique problems, as each individual case, as with all Aneurysms, must be assessed to determine the best course of treatment. There are several different methods available to treat Giant Aneurysms and a combination of both surgical and Endovascular methods is not uncommon. This combined approach is reporting the highest percentage of favorable outcomes. The treatment a physician chooses or recommends for a particular Aneurysm is based on several factors including the patient’s age, overall health, Aneurysm size, and location among others.
Surgical
Direct surgical treatment includes clipping and proximal occlusion and trapping of the aneurysm using clips or ligature above and below the lesion. Clipping may not always be feasible as a thick, calcified wall might make the use of an Aneurysm Clip impossible. In such cases the opening of the aneurysm and removing intra-aneurismal clot and Aneurysmorrhaphy-the suturing of the Aneurysm sac-may be necessary. If a patient is unable to tolerate the occlusion of the parent vessel, bypass procedures can be performed followed by trapping or occlusion of the vessel. Bypass and reconstruction of the artery with vein grafts is also possible in some situations.
Endovascular
The use of Coiling (Guglielmi detachable coils) a common method of treatment in small Aneurysms is also an option. Though with this procedure there is concern regarding the possibility of coil migration. Other Endovascular techniques include intravascular trapping with balloons above and below the Aneurysm and proximal balloon occlusion.