Outcome Analysis of the Flow Diversion with Pipeline Embolization Device for the Surgical Treatment of Unruptured Large and Giant Paraclinoid Carotid Aneurysms

Background: Both the high frequency of recurrence of large or giant paraclinoid aneurysms (PA) of the internal carotid artery and the occurrence of intra- and postoperative complications, leading to unsatisfactory results of surgical treatment of this group of patients, make the stated problem urgent. Flow-diverter embolization devices are actively used in many large international neurosurgical centers for the treatment of cerebral aneurysms of different morphology, size, and localization. Currently, there are very few reports on the effectiveness of the use of flow diverting stents in the surgical treatment of large and giant PA of the internal carotid artery. The results of these studies are controversial and largely contradictory. 

Aim: Outcome analysis of the use of Pipeline embolization device (PED) for the surgical treatment of large and giant carotid PA. Methods: The study enrolled 37 patients (25 women, 12 men; mean age 51.7±10.7 years) who were divided into those treated with the PED alone versus those treated with the PED and concurrent coil embolization. The average follow-up period was 19.7±3.8 months. 

Results: In 56.7% of cases, PA caused the development of an insignificant neurological deficit (Modified Rankin Scale 1−2). In 18.9% of patients, PA provoked a gross neurologic deficit (MRS 3−5). 24.3% of patients with PA did not have any clinical-neurological manifestations. After the surgery, neurologic status improved in 32.4% of patients, remained the same — in 45.9% of cases, and the degree of neurologic deficit increased in 21.6%. PED procedure was performed in 70.2% of patients. In 29.7% of cases, the dislocation of large or giant PA of the internal carotid artery from the systemic blood stream was performed using PED and concurrent coil embolization. At the indicated period of patient observation, complete occlusion of large and giant carotid PA was achieved in 75.6% of cases, almost complete and partial occlusion — in 24.3%. The incidence of thromboembolic and hemorrhagic complications was 10.8% and 8.1%, respectively. Mortality rate among patients was 2.7%. 

Conclusions: The use of PED is an effective method for occluding large or giant PA of the internal carotid artery. Nevertheless, this method of endovascular treatment of PA is associated with a high complication incidence.