Reconstructive endovascular approach for a cavernous aneurysm in infancy

Reconstructive endovascular approach for a cavernous aneurysm in infancy

Cohen, Jose E

We report a unique case of endovascular arterial reconstruction using stent and coils in a symptomatic cavernous aneurysm presented in infancy. A 3-year-old infant presented with a partial cavernous sinus syndrome secondary to a bilobulate cavernous aneurysm with subarachnoid extension. Direct clipping represented a considerable challenge and trapping after bypass grafting was considered too risky. A combined endovascular approach using stent and coils was performed. A 4 x 18 mm balloon-expandable stent was then placed across the aneurysm orifice allowing the complete obliteration of the remnant with coils implanted through the stent mesh. Digital substraction angiography documented patency of the ICA lumen and complete obliteration of the aneurysm. A 24-months angiographie follow-up was performed confirming persistent aneurysm exclusion and patency of the parent vessel with no signs of in-stent de novo stenosis. Reconstructive endovascular technique using stent and coils allowed the treatment of a complex vascular condition. The cavernous lesion was excluded from the circulation while preserving normal flow through the parent vessel and its branches. Long-tern follow up is a major concern, specially in pediatric patients but the 24 months angiographic follow-up is encouraging. [Neurol Res 2003; 25: 492-496]

Keywords: Cerebral aneurysm; endovascular therapy; embolization; stent

INTRODUCTION

Intracavernous internal carotid artery (ICA) aneurysms represent 3%-5% of all intracranial aneurysms. However as neuroimaging evolved the diagnosis of cavernous aneurysms increased markedly. Their natural history suggests that a large number of such aneurysms will remain asymptomatic and carry low rates of rupture and mortality compared to subarachnoid space aneurysms3,4. Therefore, most asymptomatic aneurysms do not require surgical treatment.

Surgical approaches are challenging and hazardous and are indicated for selected cases of subarachnoid extension and for symptomatic lesions causing considerable morbidity such as pain and cranial nerve deficits, carotid cavernous fistula, epistaxis or subarachnoid hemorrhage or thromboembolic complications2,6. Surgical, endovascular and combined experiences on cavernous aneurysms in infants are very limited, due mainly to the rarity of these lesions in the pediatric age.

Primary coiling is currently restricted for the treatment of aneurysms with a favorable neck-to-body ratio. Most of the cavernous lesions harbor a considerable size at presentation and a wide neck that practically cannot be diferentiated from the underlying deformed cavernous ICA. These result in an unfavorable geometry for primary coiling. When a single therapeutic modality cannot achieve the desired effect without increased risks, the ability to combine techniques may lead to the safe and complete occlusion of the aneurysm. The combination of stents and detachable coils has been suggested for extracranial, as well as intracranial, aneurysms and the combination is currently considered an alternative to single stent placement or other techniques such as remodelling technique or parent vessel occlusion.

We report a case of an infant with a broad-based cavernous aneurysm obliterated with a combined endovascular technique using stent and coils. To our knowledge, this combined endovascular technique was not previously reported in the pediatric age.

CASE REPORT

A 3-year-old girl, with a history of intra-orbital abscess requiring surgical evacuation was brought to neurological consultation because of a sudden onset left eye deviation and ptosis noticed by her parents. The patient was alert and responsive and the physical examination was unremarkable except for a partial left oculomotor palsy that spontaneously recovered after seven days.

A computerized tomography and an MRI scan of the head demonstrated the presence of a bilobulate vascular mass into the left cavernous sinus. Digital substracted angiography revealed details of a bilobulate cavernous aneurysm, broad-necked arising from the anterior bend and horizontal portion of the cavernous ICA (Figure 1). Due to the age of the patient and the requirement of general anesthesia, balloon test occlusion of the left internal carotid artery was not performed but Mattas and Allcok tests suggested adequate collateral filling through both the anterior and posterior communicating arteries.

Operative Technique

After informed consent was obtained, the patient was taken to the endovascular suite for subsequent cerebral angiography and endovascular treatment. General anesthesia was indicated. Unilateral arterial approach after standard Seldinger puncture and catheterization was used and an 8French (8F) introducer sheath in the right femoral was placed under full heparinization. At the start of the procedure the patient received a heparin bolus (2000-IU) and every catheter was constantly flushed with saline and heparin (1U heparin per mililiter of isotonic sodium chloride solution). The patient received uncoated aspirin (100 mg po qd) for three days prior to stenting procedure. Selective angiography was performed and the target lesion was outlined in multiple projections with rotational tridimensional angiography. A 6-Fr guide catheter (Envoy; Cordis, Miami Lakes, FL, USA) was advanced into the left ICA using a standard 0.035 inch guidewire. Pre-procedural measurement of the aneurysm and parent vessel was performed with the use of online quantitative angiography (lntegris, Phillips Medical Systems The Netherlands). The length of the aneurysm neck was 5 mm, and the reference ICA diameter was 3 mm. A Prowler10 microcatheter (Cordis) with a 0.014 inch, 300 [mu]m exchange nitinol guidewire was carefully navigated through the distal supraclinoid ICA beyond the aneurysm and as far as the sphenoidal silvian segment. The microcatheter was removed and exchanged for a balloon-expandable 4 x 18 mm stent (AVE GFX, Arterial Vascular Engineering, Santa Rosa, CA, USA). The stent was navigated under fluoroscopy and positioned across the aneurysm neck (Figure 2A,B). The balloon catheter expanded the stent to 3 mm by using six atmospheres of pressure and was then withdrawn.

The microcatheter was then advanced assisted with a microguidewire and positioned across the interstices of the implanted stent into the right lobule of the aneurysm body. With the stent as a mechanical barrier three 8 x 25 mm J-shape mechanically detachable coils (Cook Inc., Bjaeverskov, Denmark) were deployed within the body and neck. Four additional helical coils (Micrus Corporation, Mountain View, CA, USA) measuring 6 x 20mm, 5 x 20mm, 4 x 10mm and 3 x 10mm were implanted. After a compact cast was achieved the microcatheter was removed and repositioned into the left lobule and through the stent mesh. Three 8 x 25 mm J-shape mechanically detachable coils (Cook Inc.) were deployed within the body and neck. Four additional helical coils (Micrus Corporation) measuring 6 x 20 mm, 5 x 20 mm, 4 x 10 mm and 3 x 10 mm were implanted. An angiogram demonstrated almost complete occlusion of the butterfly aneurysm (Figure 3A,B). After completion of the procedure, the heparin administration was stopped and the drug effects were allowed to wear off gradually. The patient received aspirin (100mg day^sup -1^) for three months.

Neurological and angiographic follow-up

The patient evolved favorably and was discharged after four days with no neurologic sequelae. A follow-up angiogram obtained after two years showed persistent almost complete obliteration of the aneurysm with excellent flow through the supraclinoid ICA and no evidence of angiographie in-stent de novo stenosis (Figure 4).

DISCUSSION

Modern endovascular techniques allow the treatment of intracranial aneurysms in many circumstances when surgery is associated with significant morbidity such as for intracavernous aneurysms. GDC treatment has become an accepted therapy and for certain aneurysms has achieved results equal or superior to surgical clipping7, however every aneurysm shape may not be amenable to endovascular coiling. Wide necked aneurysms, such as most of cavernous aneurysms, will not provide a stable positioning of coils and the spirals are more likely to protrude into the arterial lumen or even migrate. The first endovascular answer to these problematic lesions was the remodeling technique with a nondetachable blocking balloon, a technically demanding procedure requiring the simultaneous use of two microcatheters and usually necessitating the use of a larger guide catheter or the use of an additional one, with additional complications. On the other hand, new different coil designs like the bi-dimensional (2D)-shape and three-dimensional (3D)-shape GDC versions achieved a moderate rate of success. The latter has a secondary structure consisting of a series of omega-like loops that form a complex cage after deployment, thus decreasing the risk of a single loop herniating into the lumen of the parent vessel8.

Technical limitations related to the inability to navigate a stent and the delivery system through tortuous vascular segments have limited their application in intracranial lesions. Recently, newly designed flexible stents are being used with increasing frequency and provide the potential to expand the endovascular treatment of intracranial aneurysms. Theoretically, stent-grafts are the ideal implants for covering arterial aneurysms of the cavernous segment, but at present they are still in technical development. They have several disadvantages, such as increased thrombogenicity and inflammatory reaction with subsequent intimai hyperpiasia9. Moreover, they are less flexible than bare stents.

On the basis of our preliminary experience with the use of intracranial stents for arterial reconstruction we decided to implant a stent in the cavernous carotid segment thus, providing the basis for arterial reconstruction10,11. This step was performed with the aid of adequate proximal support, successful supraclinoid microcatheterization, distal support and a proper selection of a flexible balloon-mounted stent. As expected, only a minor change in the filling of the aneurysm was visible immediately after stent implantation. At this stage, a second overlapping stent could have been placed in order to reduce the final stent porosity12,13 however, due to the unfavorable aneurysm neck/parent vessel diameter this technique is very unlikely to promote a major intra-aneurysmal flow change. Furthermore, the double stent mesh would have limited the placement of a microcatheter for secondary coiling or liquid embolization with the resultant of an inadequate and incomplete treatment. In this instance, we favored the stent-assisted coiling technique, a combined technique that, although technically demanding, gained rapid acceptance in the treatment of widenecked aneurysms, pseudo-aneurysms and dissecting aneurysms not amenable for primary coiling or clipping9-11,14-18. Procedural images demonstrated complete obliteration of the aneurysm and parent artery preservation.

An issue of major concern relates to long-term follow up, specially when dealing with pediatric patients. The implanted stent was selected based on the parent artery dimensions and keeping in mind the standardized measurements of the adult cavernous carotid in order to avoid a future relative segmental stenosis. The two year angiographic follow-up demonstrated a persistent aneurysm occlusion with no signs of in-stent stenosis and constitutes an evidence of long term intracranial stent patency and persistent aneurysm occlusion.

Infants with complex, broad necked, cavernous aneurysms with anticipated surgical difficulty can be successfully treated with a combination stent and coils.

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Jose E. Cohen*, Angel Ferrario, Rosana Ceratto, Carlos Miranda and Pedro Lylyk

Department of Nourosurgery and Interventional Neuroradiology, ENERI, Clinica Medica Belgrano, Buenos Aires, Argentina,

*Department of Neurosurgery and Neuroendovascular Surgery, Hadassah Medical Center, Jerusalem, Israel

Correspondence and reprint requests to: Jose E. Cohen, MD, Department of Neurosurgery and Neuroendovascular Surgery, Hadassah Medical Center, POB 12000, 911 20 Jerusalem, Israel. [jcohenns@yahoo.com] Accepted for publication February 2003.

Copyright Forefront Publishing Group Jul 2003

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