Keywords
thrombosed - giant fusiform aneurysm - vertebral artery - coils embolization - outcome
Introduction
Giant fusiform aneurysm of the vertebral artery (VA) is one of the rare vascular entities,
describing 4 to 6% of all intracranial giant aneurysm.[1]
[2]
[3]
[4] These fusiform aneurysms usually present with thrombosis because of turbulent blood
flow and gradually become larger causing mass effect on the medulla oblongata resulting
in poor prognosis. Open surgical clipping with decompression by aneurysmectomy could
relieve mass effect earlier. Surgical therapy for such aneurysms is effective; however,
it is challenging in consequence of their location on the medulla oblongata, wide
necked, and intra-aneurysmal thrombosis.[2]
[3]
[5]
[6] With advancement of techniques and tools, endovascular therapies (EVTs) have been
well established for these aneurysm treatments at present date. Furthermore, EVT is
usually applied for unruptured giant fusiform VA aneurysm and could not relieve from
mass effect, which may result in continuous compression causing medulla oblongata
infarction, leading to death.[7] Therefore, we report a case of almost completely thrombosed giant fusiform unruptured
aneurysm of V4 segments of VA that was treated by EVT with complete occlusion of the
aneurysm by coil packing.
Case Presentation
Case Presentation and Endovascular Technique
A 35-year-old young female without any relevant medical or traumatic history visited
our hospital due to mild posterior headache, pain along with numbness, and tingling
sensation over the right posterior neck and shoulder for 1 month, but severe right
posterior neck pain for 1 day before admission. Magnetic resonance imaging (MRI) of
cervical spine was done, which reveled normal cervical spine. Brain MRI was done for
further investigation, which reported an almost complete thrombosed giant dolichoectatic
right VA causing compression upon the adjacent medulla oblongata and inferior pons
([Fig. 1A] and [B]). Digital subtraction angiography (DSA) was also done for further evaluation of
the vascular anatomy, which revealed an almost completely thrombosed giant fusiform
aneurysm of the V4 segment of the right VA measuring 35.55 mm (length) × 7.16 mm (maximum
diameter) × and 4.00 mm (minimum diameter) ([Fig. 1C]). Proximal part of the aneurysm of the VA was normal. Posterior inferior cerebellar
artery (PICA) originated just proximal to the origin of the aneurysm. No any major
branches or perforators were seen around the aneurysm. Patient did not have any other
neurological symptoms except neck pain and numbness. On DSA, the anterior spinal artery,
which has a potential risk of thrombus occlusion, was not seen ([Fig. 1G] and [L]).
Fig. 1 Axial and sagittal section of T2-weighted brain magnetic resonance imaging (MRI)
showing almost complete thrombosed fusiform aneurysm of vertebral artery over the
medullary region (A). Lateral view of the left vertebral artery injection (digital subtraction angiography
[DSA]) and three-dimensional (3D) DSA showing almost completely thrombosed giant aneurysm
of the V4 segment of the right vertebral artery measuring 35.55 mm (length) × 7.16 mm
(maximum diameter) × 4.00 mm (minimum diameter) (B and C). Digital subtraction angiography (D) showing fusiform aneurysm with guiding catheter(yellow arrow), first microcatheter,
SL-10 (blue arrow), and second microcatheter, Phenom-17 (red arrow). DSA (E) showing deployment of the first two coils and yellow arrow showing Sterling Monorail
percutaneous transluminal angioplasty (PTA) balloon dilation catheter, 4F, 4.5 mm × 20 mm.
DSA (F and G) showing complete occlusion of aneurysm with coils with patency of contralateral
vertebrobasilar artery. Postoperative bone and brain window computed tomography (CT)
of head showing complete embolized aneurysm without hemorrhage and infarction (H). Follow-up CT head at 1 month and brain MRI at 3 months showing normal brain, brainstem,
and spinal cord without any infarction (I–L).
EVT was performed under general anesthesia using a monoplane DSA machine (Siemens,
Germany). Bilateral femoral artery accesses were performed with 6F femoral sheath,
and 5,000 IU heparin was given from right femoral sheath. Activated clotting time
(ACT) was measured for the evaluation of anticoagulation. ACT value (> 250 seconds)
was aimed to double the baseline ACT value after heparin injection. Note that 6F distal
access guiding catheter, Envoy (Cerenovus, Johnson & Johnson), was navigated in few
centimeters proximal to the PICA through 0.035 inch gliding wire (Terumo; Cook Medical).
A diluted concentration of 1,000 IU heparin/1,000 mL normal saline was administered
slowly through both guiding sheaths (Envoy) continuously throughout the procedure.
Similarly, 10 mL nimodipine/1,000 mL normal saline was administered slowly with microcatheter
(Excelsior SL-10; Stryker Neurovascular, United States) throughout the procedure.
Envoy (Cerenovus, Johnson & Johnson) was navigated in the left VA to observe patency
of posterior circulation, which was kept till complete occlusion of the aneurysm.
Sterling Monorail percutaneous transluminal angioplasty (PTA) balloon dilation catheter,
4F, 4.5 mm × 20 mm (Boston), was advanced across the vertebrobasilar junction through
left Envoy to prevent distal migration of coils and thrombus till the first two coils
were deployed. Microcatheter (Excelsior SL-10) was advanced near the distal part of
the aneurysm and the second microcatheter Phenom 17 (Medtronic, Irvine, California,
United States) was advanced toward the proximity of the aneurysm through a 0.014 inch
microwire (Synchro 2 soft; Stryker Neurovascular, United States; [Fig. 1D]). Then, the microwire was removed and Target 360 supersoft 10 mm × 30 cm sized coil
(Stryker Neurovascular) was deployed through the first microcatheter (SL-10) and then
Axium Prime Extra Soft 10 mm × 40 cm sized coil (EV3 Neurovascular, Medtronic) was
advanced through Phenom 17, but was not deployed till third coil, Axium Prime Extra
Soft, 25 mm × 50 cm (EV3 Neurovascular) was advanced through SL 10. Axium Prime Extra
Soft 22 mm × 50 cm deployment was done by SL 10. Afterwards, SL-10 was advanced in
the right PICA for supporting coil packing as well as for preventing from the prolapse
of coils into the PICA. Then, Axium Prime Extra Soft 10 mm × 30 cm and 8 mm × 30 cm
and Target 360 super soft 8 mm × 20 cm were deployed one by one through the microcatheter,
Phenom -17, and PTA balloon ([Fig. 1E], yellow arrow) where complete coil embolization was seen ([Fig. 1F] and [G]). Postoperative period went uneventful ([Fig. 1H]). She was discharged well on tablet aspirin 75 mg/day. Patient was counseled to
follow-up at 1, 3, 6, and 12 months following discharge from hospital. Angiographic
evaluation was decided to be obtained at 6 months after the procedure until the patient
had any neurological compromise. She visited the hospital with improvement in her
symptoms without any new symptoms at the first and second follow-up period. So we
advised only computed tomography head at the first follow-up period and brain MRI
was done at the second follow-up period ([Fig. 1I–L]).
Discussion
Giant fusiform aneurysm of the V4 segment of the VA with thrombosis is rarely reported
among giant intracranial aneurysm.[8] The major causative factor of vertebral aneurysm such as trauma, arteriosclerosis,
vasculitis, as well as connective tissue disorder have been reported in previous literatures.[9]
[10] In our report, the patient had no history of trauma, medical illness, and serological
abnormalities, which is consistent with the report of other study.[11] Thrombosed fusiform aneurysm of the VA expand gradually into giant aneurysm resulting
in compressive mass effect on the medulla oblongata.[5] The precise mechanism for growth of VA aneurysm is unclear, even though intra-aneurysmal
thrombosis, repeated hemorrhage and remodeling of the wall of aneurysm,[12] and obvious vasa vasorum development on the occluded parent artery[4] have been explained in previous literature.
Our patient had symptoms including mild occipital headache, severe right posterior
neck pain, numbness, and tingling sensation over the right shoulder, which may be
compression of the brainstem or abnormal pulsation of giant thrombosed aneurysm. Similarly,
the following symptoms such as headache, dizziness, dysarthria, diplopia, dysmetria,
hearing loss, neck pain, dysphasia, gait disturbance, hemi- or tetraparesis, or paraparesis
have been found associated with giant fusiform VA aneurysm.[8]
[13]
[14]
[15] Thrombosed VA aneurysms widen gradually and may rupture, which can be fatal for
the patient, therefore earlier treatment strategies should be thought. Thrombosed
giant aneurysm is one of the troublesome vascular diseases, and these can be managed
by thrombectomy with clip reconstruction or bypass with parent artery occlusion other
than traditional clipping alone.[4]
[15] Surgical treatment is effective for instant relief from mass effect; however, it
is challenging because of the location of the aneurysm near the brainstem and vascular
tortuosity, and for these reasons good experience, knowledge, and skills of skull
base surgery should be necessitated.[16] EVT, internal trapping with coils, and flow diverter stenting for such thrombosed
large or giant fusiform VA aneurysms are the established choice of treatment methods;
however, these EVTs are associated with higher rate of ischemic complications, morbidity,
and mortality compared to anterior circulation aneurysm.[4]
[7]
[17] Occlusion of the ipsilateral VA may lead to ischemic changes of 8% if blood flow
in the contralateral VA is inadequate.[18] Therefore, reconstruction procedure is adopted if VA on the aneurysm side does bear
ischemic changes.[19] In our patient, deconstruction method was contemplated to be sustainable because
the aneurysm of the V4 segment of VA was almost completely thrombosis with no major
neurological symptoms except neck pain and numbness and blood flow to both PICA from
both ipsilateral VA.
Our patient had an almost completely thrombosed giant fusiform unruptured aneurysm
of V4 segments of VA who was treated by EVT with complete coil packing of the aneurysm.
We performed double microcatheter technique. We first deployed coils in more distal
part of the aneurysm and coil packing was done one by one from distal to proximal.
Envoy (Cerenovus, Johnson & Johnson) was navigated in the left VA to observe patency
of posterior circulation during embolization. Sterling Monorail PTA balloon dilation
catheter, 4F, 4.5 mm × 20 mm (Boston), was advanced to the left, Envoy, across the
junction of the vertebrobasilar artery to prevent migration of coils and thrombus
distally. EVT with trapping for the management of thrombosed large or giant VA aneurysm
may be effective for aneurysm at the nonbranching site.[4]
[8] Similarly, Masahiro et al.[8] described the management of thrombosed large fusiform VA aneurysm by short segment
internal trapping using N-butyl-2-cyanoacrylate and platinum coils. Furthermore, internal
trapping for short distance with few coils alone might cause incomplete aneurysm occlusion
when distance between aneurysm and perforator or branching vessels such as PICA is
extremely short, which might be associated with medulla oblongata infarction.[8]
[20]
[21] But, if a large number of coils are placed in fusiform aneurysm to complete trapping
it may get worse by mass effect.[8] In this report, we described a complete occlusion of aneurysm with double microcatheter
technique along with support of PTA balloon maintaining patency of contralateral VA
and PICA and no neurological deficit and infarction was reported after the procedure
in our patient. However, the treatment by endovascular therapy for thrombosed large
or giant VA aneurysm is not only the treatment strategy (destructcive or constructcive)
with device (stent, coils or flow diverter), but also long term occlusion. Even with
internal/external trapping, aneurysm may change and regrow in the long term, so we
can say that the aneurysms have been cured after observation for several years or
more. Therefore, this report has some limitations like it is retrospective, a case
report, and short-term follow-up period. Therefore, long-term clinical and radiological
outcomes are required to assess the effectiveness of this present report.
Conclusion
Giant fusiform aneurysm of the V4 segment of the VA associated with almost completely
thrombosed may mimic symptoms of cervical radiculopathy. Complete occlusion of almost
completely thrombosed giant fusiform V4 segment VA aneurysm by EVT with coil embolization
is safe and effective. To validate this report more investigations and analysis of
further cases and observation of long-term follow-up data are required.
