Seventeen consecutive adult patients with 21 wide-necked intracranial saccular aneurysms were included in the study. Prior to treatment, the neurovascular team considered the options of observation, open surgical and endovascular repair in each case. Angiographic studies obtained in all aneurysms were reviewed by the attending endovascular neurosurgeon (D.K.L). All saccular bifurcation aneurysms included in the study had a wide neck, defined as a dome-to-neck ratio of less than 2 or a neck that was 4 mm or wider as measured on angiography [10, 11]. A signed informed consent was obtained for each patient. Demographic data obtained and recorded for each patient included clinical history, aneurysm location and dimensions, technical difficulties, and complications. Immediate post-procedure angiography was performed to determine degree of aneurysm occlusion and parent vessel patency. A frequently updated database with the aforementioned data was retrospectively reviewed. This study was conducted in accordance to and with approval by the Rush University Medical Center Institutional Review Board.

Between June, 2010 and September, 2010, we deployed 30 Neuroform EZ stents in 17 patients (12 women) for treatment of 21 wide-necked cerebral aneurysms. The mean age at the time of treatment was 56.3 years (range 37-79 years). Stents were deployed in an overlapping manner in 7 patients, and a y-stent configuration was used to reconstruct the parent vessels of 2 aneurysms [12, 13]. There were 3 aneurysms located at the cavernous carotid segment, 3 at the origin of the ophthalmic artery, 4 at the superior hypophyseal artery, 4 at the posterior communicating artery, 1 along the posterior carotid wall, 1 on the A1 segment of anterior cerebral artery, 2 at the anterior communicating artery, 2 at the middle cerebral artery bifurcation, and 1 at the basilar bifurcation. The average maximum diameter of the 21 aneurysms was 8.3 mm (range 2.5-24.0 mm) with average neck 5.7 mm (range 2.0-17.9 mm). Three aneurysms initially treated via coiling only were found to have recurrent filling on 6-month follow-up; these were treated via stent-assisted coiling with the Neuroform EZ stent and included in the study. In unruptured and previously treated aneurysms, the Neuroform EZ stent was placed across the neck of the lesion prior to coil embolization. In the case of the one acutely ruptured aneurysm, a Neuroform EZ stent was deployed after coil embolization as post-coiling angiography demonstrated parent artery compromise.

Patients treated electively receive anti-platelet pharmacotherapy (325 mg aspirin and 75 mg clopidogrel daily) starting 5 days before the procedure. The one patient who presented with subarachnoid hemorrhage was loaded with anti-platelet medication following the procedure. Intra-operative heparinization to an activated clotting time of 250 seconds is maintained throughout the procedure. Dual anti-platelet therapy continues for three months after the procedure and for six months when more than one stent is placed.

After diagnostic angiography is performed, working views are obtained for stent delivery. The appropriate Neuroform EZ stent length is selected (lengths available were 10, 15, 20 and 30 mm) to allow the ends of the device to extend at least 5 mm beyond the neck of the aneurysm on each side. All stents deployed were 4.5 mm in width to maximize vessel apposition and increase metal to artery ratio.

A guide catheter is positioned in the cervical segment of the target vessel. A microcatheter (Renegade Hi-flow (Stryker) or Marksman (Covidien)) is navigated as distally as possible beyond the aneurysm neck. The Neuroform EZ stent loading sheath is introduced into a rotating hemostatic valve connected to the microcatheter and continuous heparinized saline flush. Back flow of saline from the valve preps the system through the loading sheath. The loading sheath is inserted to the hub of the microcatheter and the rotating hemostatic valve is tightened around the sheath. The stent is introduced into the microcatheter under direct visualization through the transparent tip of the loading sheath. The stent and delivery system are then advanced beyond the aneurysm neck within the microcatheter; the microcatheter is withdrawn while keeping forward pressure on the stent delivery system, unsheathing the stent across the neck of the aneurysm. The catheter can be manipulated forward and backward to control speed of deployment and expansion of each open cell unit.

Visualization of the four platinum marker bands at each end of the stent confirms proximal and distal placement within the parent vessel. After stent deployment, a Synchro 14 (Stryker) microguidewire and SL 10 microcatheter are advanced through the interstices of the stent into the aneurysm to allow coil embolization.

Patients were evaluated by angiography at the end of the procedure to document aneurysm obliteration. A qualitative assessment of aneurysm occlusion was performed using a 3-point Raymond scale [14]: 1) complete aneurysm occlusion without contrast filling; 2) residual neck; and 3) residual aneurysm sac. In all cases, aneurysm occlusion was interpreted on the basis of the images obtained immediately after placement of the last coil. The senior author evaluated the clinical outcome at discharge and follow-up with modified Rankin score (mRS) [15]. Six-month follow-up angiography was performed on 18 of the 21 treated aneurysms. Two patients with a total of 3 aneurysms are clinically stable but are still awaiting angiographic follow-up.

Technical complications occurred in 4 patients, including prolapsed coils, vasospasm, and parent vessel compromise, all of which had no clinical significance.

In case 5, a Neuroform EZ stent was placed across a wide-necked superior hypophyseal artery aneurysm followed by coiling. Unfortunately, the first coil stretched and prolapsed into the parent vessel. An Enterprise stent (Codman, Miami Lakes, FL, U.S.A.) was deployed, overlapping the Neuroform EZ stent to keep the prolapsed coil segment out of the vessel lumen. In case 8, after deployment of a Neuroform EZ stent across the neck of a carotid ophthalmic artery aneurysm and carotid cavernous aneurysm, coil packing of the two separate aneurysms through the stent initially resulted in partial prolapse of coil mass into the parent vessel. A second Neuroform EZ stent was placed successfully. Post-procedure angiography demonstrated no parent vessel compromise in these two cases, nor were there any clinical sequelae.

In case 13, after coiling a basilar tip aneurysm, post-procedure angiography demonstrated prolapsed coils, occluding the small left posterior cerebral artery. A Neuroform EZ stent was placed from the right posterior cerebral artery to basilar artery. Prior to closure, a left common carotid artery angiogram demonstrated a fetal origin of the left posterior cerebral artery. The patient remained neurologically intact.

In case 14, while treating a wide-necked anterior communicating artery aneurysm, there was iatrogenic vasospasm resulting in mild changes in somatosensory evoked potentials. Potentials returned to baseline after use of intra-arterial nicardipine and blood pressure augmentation. The patient had no new neurologic deficits after the procedure.

Selective embolization was successfully performed and resulted in an excellent clinical outcome in all patients. One patient had a groin hematoma without evidence of pseudoaneurysm or arteriovenous fistula on ultrasound and without clinical sequelae. One patient had elevated troponins post-procedure related to demand ischemia without clinical consequence. There were no treatment-related deaths or clinically evident neurological complications. The one patient who presented in the acute stage of subarachnoid hemorrhage (ruptured basilar tip aneurysm) did well post-operatively and was discharged home on post-operative day 11. All seventeen patients were discharged home with a good clinical status (mRS 0, n = 11; mRS 1, n = 6). All patients were clinically evaluated approximately six months after aneurysm treatment, and none had evidence of treatment-related complications.

Follow-up angiography (Table 1) showed total occlusion in 12, residual neck in 3, and residual aneurysm filling in 3. Retreatment was performed for the three aneurysms with residual filling. Two of these had further coiling for coil compaction without complication; follow-up angiography of these retreatments is pending. The third patient also had further coiling for compaction inside a particularly challenging partially thrombosed large wide-neck aneurysm; there was continued residual filling on his subsequent follow-up. A third procedure involving non-Neuroform stent was performed on this patient which was complicated by a late intracerebral hemorrhage despite Raymond class 1 occlusion on post-intracranial hemorrhage angiography. There was no significant stenosis within the stent constructs of the eighteen aneurysms with follow-up. We continue to follow all patients in this series, and to our knowledge, no others have had aneurysm-related clinical problems.