Carotid artery occlusion for the treatment of symptomatic giant carotid aneurysms: a proposal of classification and surgical protocol

Distal Endovascular Occlusion for Incomplete Occlusion of Cavernous Carotid Aneurysms after High-flow Bypass and Cervical Internal Carotid Artery Ligation

Internal carotid artery (ICA) ligation for placing a high-flow extracranial-intracranial (EC-IC) bypass is used in patients with aneurysms on the cavernous portion of the ICA. Recanalization and rupture after proximal ICA ligation can occur. We present four patients who underwent endovascular distal ICA occlusion and report our surgical technique and treatment results. We ligated the ICA to place an EC-IC bypass using a radial artery (RA) graft. Failure to obtain spontaneous occlusion in the distal region required endovascular treatment an average of 219 days later. A guide catheter was placed in the common carotid artery, a guide or distal access catheter was introduced in the RA graft from the external carotid artery, and a microcatheter was navigated into the cavernous aneurysm through the RA graft. Using detachable coils, endovascular ICA occlusion was from just distal to the aneurysmal neck to a site proximal to the origin of the ophthalmic artery. Aneurysmal occlusion was completed by endovascular occlusion of the distal ICA. Complications were RA graft stenosis and transient consciousness disturbance due to local subarachnoid hemorrhage. Outpatient follow-up for a mean of 109.5 months revealed no recurrences. Distal occlusion of the ICA through the implanted RA graft is simple and presents a low risk for cerebral infarction due to thrombus formation during the procedure. To treat cavernous carotid aneurysms that do not disappear after placing the EC-IC bypass after ICA ligation at the aneurysmal neck, we offer our procedure as a treatment option.

What does computational fluid dynamics tell us about intracranial aneurysms? A meta-analysis and critical review

Despite the plethora of published studies on intracranial aneurysms (IAs) hemodynamic using computational fluid dynamics (CFD), limited progress has been made towards understanding the complex physics and biology underlying IA pathophysiology. Guided by 1733 published papers, we review and discuss the contemporary IA hemodynamics paradigm established through two decades of IA CFD simulations. We have traced the historical origins of simplified CFD models which impede the progress of comprehending IA pathology. We also delve into the debate concerning the Newtonian fluid assumption used to represent blood flow computationally. We evidently demonstrate that the Newtonian assumption, used in almost 90% of studies, might be insufficient to describe IA hemodynamics. In addition, some fundamental properties of the Navier-Stokes equation are revisited in supplementary material to highlight some widely spread misconceptions regarding wall shear stress (WSS) and its derivatives. Conclusively, our study draws a roadmap for next-generation IA CFD models to help researchers investigate the pathophysiology of IAs.

"Clip Anchor-Assisted Coil Embolization" for Endovascular Parent Artery Occlusion of Intracranial Traumatic Aneurysm

Traumatic cerebral aneurysms are histologically dissecting aneurysms or pseudoaneurysms, thus requiring parent artery occlusion for cure. Combination of endovascular parent artery occlusion and extracranial-intracranial bypass is considered optimal to obtain complete obliteration of the aneurysm and to avoid hemodynamic hypoperfusion. However, endovascular parent artery occlusion of the supraclinoid internal carotid artery (ICA) is at risk of ischemic complications due to distal coil protrusion to adjacent perforating arteries or distal embolism of the thrombi generated in the coil mass. A 20-year-old man presented with progressive left optic neuropathy following motor vehicle accident. Radiological examination revealed left supraclinoid ICA aneurysmal formation with dissecting change. We treated this traumatic supraclinoid ICA aneurysm by combination of endovascular parent artery occlusion and high-flow bypass in the hybrid operating room. An aneurysmal clip was applied on the ICA just distal to the aneurysm prior to coil embolization, and worked as a scaffold for subsequent filling coils and as a blockade for the distal emboli. This "clip anchor-assisted coil embolization" technique resulted in optimal parent artery occlusion for the traumatic aneurysm of the supraclinoid ICA with minimal risks of residual blood flow, intraoperative rupture, and thromboembolic complications.

Magnetic Resonance Angiography-based Prediction of the Results of Balloon Test Occlusion

Precautious balloon test occlusion (BTO) is sometimes performed in cases of high-risk intraoperative internal carotid artery injury. We investigated whether magnetic resonance angiography (MRA) findings could predict BTO results to thus avoid the use of precautious BTO. This retrospective study, included 96 patients who underwent BTO, eight of whom underwent bilateral BTO. The relationship between the BTO results for 104 internal carotid arteries and the MRA findings obtained in 96 patients were retrospectively evaluated. On MRA, anterior cerebral artery (A1)–anterior communicating artery–A1 was defined as anterior collateral circulation (ACC), and posterior cerebral artery–posterior communicating artery was defined as posterior collateral circulation (PCC). BTO was tolerated in all 27 sides with thick ACC regardless of PCC thickness. In 31 of 44 cases with a thin ACC, the tested sides were BTO-tolerant (70.5%). Of these 44 tested sides, all five with a thick PCC were BTO-tolerant, but eight with a thin PCC and 31 with an invisible PCC showed results other than tolerance. Among cases with an invisible ACC, 10 of 33 tested sides were BTO-tolerant (30.3%). Among these 33 tested sides, outcomes other than tolerance were observed regardless of PCC thickness. Thick, thin, and invisible ACCs were assigned 3, 1, and 0 points, respectively; and thick, thin, and invisible PCCs were assigned 2, 1, and 0 points, respectively. A sum of 3 points in the ACC and PCC indicated that all sides were BTO-tolerant. In conclusion, a thick ACC or a thin ACC with a thick PCC indicates BTO-tolerance. The BTO prediction score is useful for predicting results of BTO.

Treatment Outcomes of Cerebral Aneurysms Presenting with Optic Neuropathy: A Retrospective Case Series

Background:

Optic neuropathy due to an aneurysm is relatively rare, with only a few small case series on this topic, and no randomized trials having been published until now. As such, the functional prognosis and treatment for aneurysm-induced optic neuropathy remain controversial.

Objective:

We quantified optic nerve injuries using an objective index (the visual impairment score) and evaluated prognostic factors of postoperative visual function.

Materials and Methods:

Of 960 patients treated for an unruptured intracranial aneurysm, 18 (1.9%) patients had optic neuropathy. Visual acuity and visual field were assessed before surgery and 6 months’ postoperatively. Cases were classified on the basis of treatment modality (coil embolization or flow alteration [FA]) and prognostic factors of the two treatment groups.

Results:

Of the 18 patients with an intracranial aneurysm and optic neuropathy, 12 (67%) were treated using coil embolization and 6 (33%) were FA. Visual function improved after surgery in 8 patients (44%), 5 (42%) in the coil embolization group, and 3 (50%) in the FA group. The visual function remained stable after surgery in 6 (33%) patients and worsened in 4 (22%). Patients with an aneurysms <15 mm in size had a favorable outcome (P = 0.05).

Conclusions:

Surgical treatment improved vision in 44% of cases, with no difference in the prognosis of coil embolization and FA and no effect of the duration of symptoms on outcomes. Further, the prognosis of visual function recovery was better for aneurysms <15 mm in diameter.

Emergency Non-occlusive High Capacity Bypass Surgery for Ruptured Giant Internal Carotid Artery Aneurysms

AIM

Managing ruptured giant internal carotid artery (ICA) aneurysms in an emergency situation is very challenging. By reporting two cases, we discuss the role of the Excimer Laser-assisted Non-occlusive Anastomosis (ELANA) technique as an armamentarium for cerebrovascular surgeons dealing with giant ICA aneurysms presenting with subarachnoid hemorrhage (SAH).

MATERIALS AND METHODS

The management of two consecutive patients treated with ELANA bypass during a 6-month period (June- December 2013) for ruptured giant ICA aneurysms in an emergency setting is presented.

RESULTS

The two patients presented with SAH and newly diagnosed giant ICA aneurysms (both Fisher 3; WFNS scores 2 and 4, respectively). Both patients received an emergent high-capacity extra- to intracranial (EC-IC) bypass with interposition of a saphenous vein graft between the external carotid artery (ECA) and the ICA-termination. The intracranial anastomosis was performed by the use of the non-occlusive ELANA technique. The aneurysms were successfully trapped, and there were no major complications and no major persistent morbidity in either patient. A good clinical outcome was obtained with a modified Rankin scale of 2 at the last follow-up in both patients.

CONCLUSION

Emergency ELANA bypass surgery is a useful instrument for managing patients with giant ICA aneurysms presenting with SAH. In experienced hands, the technique does not seem to carry increased risk and may expand the surgical options due to its non-occlusive nature.

Endovascular Modalities for the Treatment of Cavernous Sinus Arteriovenous Fistulas: A Single-Center Experience

BACKGROUND

Cavernous sinus (CS) fistulas are classified into traumatic and spontaneous. Traumatic carotid-cavernous fistulas (CCFs) are usually direct internal carotid artery (ICA) high-flow fistulas; whereas spontaneous CCFs are usually dural, low-flow fistulas and generally possess less severe symptoms than direct carotid-cavernous fistulas.

METHODS

This study involved 34 patients who were classified into 2 groups: Group A included 26 patients with direct carotid-cavernous fistula; and Group B included 8 patients with indirect dural cavernous fistula. All patients had ocular manifestations. One patient had subarachnoid hemorrhage. Coils were used alone in 19 cases of direct fistula and in 1 case of dural fistulas. Coils and Onyx (Covidien, Mansfield, MA, USA) were used in 7 cases of direct fistula and in 2 cases of dural fistulas. Onyx alone was used to treat 5 cases with dural fistulas but none of the cases with direct fistulas. Covered stents and coils were used in 2 cases of direct fistulas.

RESULTS

All patients in both groups showed full recovery of their clinical signs and symptoms. Only 1 procedure-related complication was observed (3%) in which a patient had an embolic event and trigeminal dysesthesia as a result of Onyx reflux through external carotid artery-ICA anastomosis.

CONCLUSION

Coils are superior solid embolic agents used for the treatment of direct high-flow fistulas, while Onyx is more valuable in dural low-flow CCF. Onyx shortens the procedure time and decreases procedure cost. Onyx injection inside the CS proper through the transarterial or transvenous route may be safer than Onyx injected inside dural arteries supplying the CS. However, more cases are needed to determine this.

Prevention of Retrograde Blood Flow Into Large or Giant Internal Carotid Artery Aneurysms by Endovascular Coil Embolization with High-Flow Bypass: Surgical Technique and Long-Term Results

BACKGROUND

Recanalization has been reported in large or giant aneurysms of the internal carotid artery (ICA) addressed by high-flow bypass and endovascular treatment. Aneurysmal recanalization may be attributable to retrograde blood flow into the aneurysm through the ICA branches, such as the ophthalmic artery or the meningohypophyseal trunk, or through the surgically created bypass. We modified the endovascular treatment of aneurysms to prevent retrograde flow and evaluated the long-term efficacy of our method.

METHODS

We used a hybrid operative/endovascular technique to treat 5 patients with large or giant aneurysms arising from the C2-C4 segment of the ICA who presented with visual symptoms due to the mass effect of the aneurysm. To prevent retrograde flow into the aneurysm our modified endovascular treatment involves coil embolization of the aneurysmal orifice and the ICA, including the origin of the ophthalmic artery and meningohypophyseal trunk, and placement of a high-flow bypass using a radial artery graft.

RESULTS

During the 5- to 12-year follow-up period, 4 aneurysms disappeared, and the other decreased in size. There were no subarachnoid hemorrhages. All bypass grafts remained patent. Visual preservation was achieved in 2 patients; 1 patient manifested visual improvement. Although 2 patients experienced transient neurological deficits we encountered no permanent complications in this series. The final modified Rankin scale of the 5 patients was 0 or 1.

CONCLUSIONS

Prevention of retrograde flow into the aneurysm by coil embolization with high-flow bypass is a safe and effective method. It prevents the recanalization of large or giant ICA aneurysms.