Wide-Neck Aneurysms

Abstract

The variability regarding the definition of a “wide-neck” aneurysm is discussed. The “uncoilable” or “difficult-to-coil” nature of the wide-neck aneurysm is the central topic of this chapter. The treatment decision-making flow for different types of wide-neck aneurysms is illustrated with figures. Multiple techniques and new devices for treating wide-neck aneurysms are reviewed. The detailed techniques reported in the literature are described and illustrated in the informative figures. These techniques include the following:

• 1. Long, “fat” coil technique.

• 2. Double-microcatheter technique.

• 3. “Special” coil technique

• 4. Balloon-assisted coiling.

• 5. Stent-assisted coiling with multiple stenting techniques, stent device selections, and stent location consideration.

• 6. New device for wide-neck aneurysm.

Case Presentation

Case 9.1 “Fat” and Long Coil Technique for Wide-Neck Aneurysms

Case Pearls

• 1. “Fat” long coil increases the first coil packing density, which is believed to lead to high chance of complete occlusion of the aneurysm.

• 2. Increase the stability of the framing coil mass to prevent coil collapse associated with additional filling coils.

• 3. More likely to get good and stable neck coverage.

(a, b) Pre-embo 3D and 2D angiograms of a small wide-neck BA tip aneurysm; (c) after first framing coil; (d) final run; (e, f) pre-embo 3D and 2D angiograms of the same patient showing another small AComA aneurysm; (g) after first framing coil; (h) final run; (i) presenting head CT, SAH pattern, as not for sure which aneurysm is the culprit aneurysm; both aneurysms were embolized; (j, k) 1-year follow-up of BA (j) and AComA (k) aneurysms

Case 9.2 Importance of High Framing Coil Percentage (FCP)

Case Pearls

• 1. Higher FCP provides good neck coverage and stable framing coil for wide-neck aneurysm.

• 2. The higher the FCP is, the more stable the framing coil mass is, and the fewer the filling coils needed, and the lesser the chance of coil prolapse/migration.

(a) Pre-embo 3D angiogram showing a small wide-neck aneurysm of terminal ICA bifurcation; (b, c) pre-embo 2D views for the best view of the neck and parent vessels; (d, f) after first framing coil (Target XL soft 2×6) with two different views, inserts: un-subtracted views showing coil contours; (e, g) final run of both views with two small additional filling coils (Target Nano 1×2×2), inserts: un-subtracted views showing coil contours of final angiograms. The high FCP reached. (h) 11-month follow-up angiogram showing the aneurysm remained completely obliterated

Case 9.3 Repeated Reposition of First Framing Coil to Reach Good Neck Coverage for a MCA Aneurysm with the Incorporation of M2 into the Neck

Case Pearls

• 1. Wit h multiple reposition of the first long “fat” framing coil, a good neck coverage avoiding blocking the incorporated branch vessel without SAC and BAC can often be reached.

• 2. Multiple reposition of the same first framing coil is safe and doable.

(a) Pre-embo 3D angiogram showing a wide-neck aneurysm with one M2 incorporated into the neck of the aneurysm; (b) pre-embo 2D views; (c, d) first and second attempted placements of the same framing coil (Target XL 4×12); the neck coverage is not ideal with partial occlusion of takeoff of the PComA (arrow); (e) anther view was chosen to show a better visualization of the M2 takeoff with third attempt with the same coil; still not satisfying (arrow show partial occlusion); (f) fourth attempted placement of the same framing coil reached the ideal neck coverage (arrow); (g) additional coil placement with stable neck coverage (arrow). (h) final run after more finishing coils (Target Nano 1.5×4×2, 1×3×2) placement; (i) 1-year follow-up (the view chosen for best view of the takeoff of M2)

Case 9.4 Multiple Repositions of First Framing Coil to Seek Ideal Neck Coverage for a Wide-Neck AComA Aneurysm

Case Pearls

• 1. Daughter lobes on the side of aneurysm are a more favorable anatomic feature (increase the dome/neck ratio) to help reach stable and good neck coverage.

• 2. Watch the neck coverage when deploying additional coil, stop when noticing the coil protrusion, and either change the catheter tip position to redirect the coil deployment or prepare for BAC or SAC if needed.

(a) Pre-embo 3D angiogram showing a wide-neck AComA aneurysm; (b) pre-embo 2D views for the best view of the neck and relationship to parent vessels; (c) a Target 360 XL 6×20 coil was tried first with protrusion in the AComA; (d) a smaller 5×20 coil used with good neck coverage; (e) three additional filling coils (Target soft, 3×10, 2×6×2) deployed with stable neck coverage; (f) final run post-coiling. Patient moved out of state, lost to follow-up, no long-term follow-up angio available

Case 9.5 Daughter Lobe Management in Ruptured Multiple Lobe Aneurysm Treatment

Case Pearls

• 1. For ruptured aneurysms, all separated lobes need to be secured given they are all likely the site of rupture.

• 2. The daughter lobe close to the neck is preferred to be coiled first and separately as it will be difficult to deal with later with the main framing coil interference.

• 3. The daughter lobe in the fundus normally self-obliterated when the body is occluded.

(a) Presenting head CT: SAH; (b) pre-embo 3D angiogram showing a wide-neck, multiple lobe BA tip aneurysm; (c) pre-embo 2D view for the best view of the neck and relationship to parent vessels; (d) coiling (Target Ultra 3×6 and 1×3) for the left daughter lobe close to aneurysm neck separately; (e) attempted first framing coil for body and two other lobes with protrusion of the coil into basilar artery lumen (Target XL 360 soft 4×8); (f) reposition of the same framing coil to avoid coil protrusion into the lumen; (g) deploy small filling coils into the main body of the aneurysm (Target Ultra 2×6, Nano 1.5×4,1×3×2); (h) finish filling of the neck of aneurysm. (i) Final run. Patient lost to follow-up, no follow-up angio available

Case 9.6 Management of a Long Shape Dumbbell Aneurysm (High Aspect Ratio)

Case Pearls

• 1. Not easy to frame whole aneurysm with good neck coverage for a long shape dumbbell aneurysm.

• 2. Framing the distal and proximal lobe separately with smaller coils may be a better option for long shape aneurysms.

• 3. Coiling the distal lobe first makes the proximal lobe become a regular round shape smaller aneurysm, which is easier to frame with good neck coverage.

(a) Presenting head CT showing SAH; (b) pre-embo 3D angiogram showing a wide-neck, multiple lobe PComA aneurysm with dumbbell long shape; (c) pre-embo 2D views for the best view of the neck and parent vessel; (d) framing the distal lobe with the coil size appropriate for that lobe; (e) framing the proximal lobe with a separate framing coil with excellent neck coverage; (f) final run after finishing coil placement showing complete obliteration of aneurysm and no neck residual

Case 9.7 Irregular Shape, Multilobe Aneurysm Coiling with Separate Framing Strategy

Case Pearls

• 1. Irregular shape aneurysm is difficult to have good neck coverage with one framing coil. Framing plan is needed to be individualized.

• 2. Use of smaller loop diameter coil to frame different lobes separately may be the better option.

• 3. The order of framing different lobes depends on the best chance of the neck coverage.

(a) Presenting head CT: SAH; (b, c) pre-embo 3D, irregular multilobe shape PComA aneurysm; (d) pre-embo 2D working views; (e) given the morphology and size of the lobe close to the neck, it is hard to embolize with good neck coverage, and the first coil is aimed to frame and embolize the distal large lobe; (f) framing and filling the proximal lobe; (g) final run post-coiling; (h) 6-month follow-up angiogram

Case 9.8 SAC as a Rescue Strategy for Coil Protrusion

Case Pearls

• 1. For wide-neck aneurysm, coil prolapse or protrusion after balloon deflation can happen during BAC.

• 2. Rescue with stent placement can prevent further complications.

(a) Pre-embo 3D angiogram showing a wide-neck ophthalmic artery aneurysm; (b) pre-embo 2D view for the best view of the neck and parent vessel; (c) BAC performed, framing coil mass stable after deflating the balloon; (d) tail of framing coil (Target XL 4×15) protruded into the parent artery lumen after second coil (Target Nano 2×4) placement and deflating the balloon; (e) final run after a stent (Neuroform EZ 4×20) was placed, insert: stent and coil contour image; (f) 6-month follow-up showing complete obliteration without recurrence, mild in-stent stenosis noticed, insert: stent and coil contour image

Case 9.9 BA Aneurysm Coiling with One Stent and “Go Through” Technique

Case Pearls

• 1. Distal end of the stent placed in PCA with more neck incorporation for better protection.

• 2. Pushing stent up in the basilar artery makes better neck coverage; often, only one stent instead of “Y” stent is needed for most of BA SAC.

• 3. “Go through” technique is more likely successful in BA tip aneurysm than sidewall aneurysm, given the angle of the microcatheter tip toward the stent interstices.

(a) Pre-embo 3D, small wide-neck BA tip aneurysm; (b, c) pre-embo 2D AP and lateral views (primary coiling was attempted without good framing and ideal neck coverage); (d) single stent placed from left PCA to BA given takeoff of left PCA is more involved in the neck; (e, f) final run post-coiling showing high packing density; (g) high magnification showing coiling catheter (arrows) going through stent interstices with good framing; (h, i) high magnification showing pushing stent (yellow line) up with more angle to narrow the neck (red line); (j, k) 6-month follow-up angiogram with RR Grade I occlusion

Case 9.10 SAC—Failed “Go Through” Technique

Case Pearls

• Different SAC techniques can be used, but “go through” technique has a high chance of success for BA tip aneurysm than side branch aneurysm.

• For side branch aneurysm, catheter tip can easily be caught in the stent cell edge preventing going through interstices given the microcatheter tip angle.

• One of the complications associated with SAC is acute stent occlusion; IA/IV antiplatelet treatment can often quickly recanalize the acute stent occlusion.

• BA tip aneurysm is one of the aneurysm locations with a high chance of recurrence with either primary coiling or SAC.

(a) Initial angiogram, after treatment and 1-year post-embo follow-up angio of a middle-aged female 5 years prior to author’s treatment, respectively; (b, c) 3D and 2D angiograms for work-up of acute headache (CT negative for SAH) showing a large BA tip aneurysm and stable residual of previously coiled left SCA aneurysm; SAC was planned to treat both aneurysms; (d, e) stent placement (Atlas 4×30, Stryker) from left PCA to BA; (f) immediate run after stent placement: acute in-stent occlusion (arrows); (g) recanalization of the stent/left PCA in several minutes after IV Integrilin bolus followed by fusion. (h) Angiogram after embolization of BA tip aneurysm; (i) attempted to catheterize the recurrent SCA aneurysm with going through technique. The tip of catheter (arrow) was incarcerated at the stent interstices. The attempts were unsuccessful with different microcatheters; (j) schematic diagram of microcatheter and stent interaction, insert: incarcerated microcatheter tip; (k) 9-month follow-up angiogram showed early recurrence of BA tip aneurysm and stable SCA recurrence; (l) retreatment of recurrent BA tip aneurysm with recoiling; (m) another 9-month follow-up angiogram with recurrence of BA tip aneurysm again and stable SCA recurrence

Case 9.11 Two-Microcatheter Technique

Case Pearls

• 1. Two-microcatheter technique is effective as an alternative strategy for wide-neck aneurysm.

• 2. The main advantage is to make the initial framing mass stable.

• 3. Pay attention to the order of the two microcatheters.

• 4. May be associated with higher emboli complications given more device in the guiding catheter.

(a) Pre-embo 3D angiogram showing a wide-neck aneurysm with dome/neck ratio ≈1. (b, c) pre-embo 2D views for the best view of the neck and parent vessel. (d, h) two working views of first framing coil (Target XL 3×9) placement through the first microcatheter; (e, i) two working views of second framing coil (Target XL 3×9) placement through the second microcatheter; (f, j) two working views of additional filling coils (Target Nano 1.5×4×2) placement through both microcatheters; (g, k) final run post-coiling

Case 9.12 Persistent Neck Residual with Multiple PEDs

Case Pearls

• 1. Multiple FD devices may be needed for definitive treatment.

• 2. Single FD device at first and add more if needed according to follow-up result.

• 3. Contrast stasis after FD device placement is a sign of high chance of aneurysm thrombosis, but is not definitive.

• 4. Neck residual after FD device treatment is a questionable indication for retreatment.

(a) Pre-embo 3D, ophthalmic artery aneurysm; (b, c) pre-embo 2D views for the best view of the neck and PED landing segments; (d, h) two views of PED embolization: immediate post-PED deployment angiogram (insert: delayed contrast stasis); (e, i) 7-month follow-up angiogram showing still significant contrast filling; (f, j) post second PED placement angiogram showing dimmish contrast filling; (g, k) 16-month follow-up angiogram from second PED with remained tiny neck residual; (l) MRA follow-up in another year showing persistent neck residual

Case 9.13 Reverse of PED In-Stent Stenosis

Case Pearls

• 1. Intravascular flow diversion is a good option for neck residual/recurrence of coiled paraclinoid ICA aneurysms.

• 2. Post-FD embolization in-stent stenosis is a well-recognized phenomenon; it was believed from the intimal hyperplasia. It can be resolved on its own over the time.

• 3. Covered PComA is often occluded if it is not a fetal PCA.

(a) Pre-embo 3D, neck recurrence of previously coiled PComA aneurysm. (b) Pre-embo 2D views for the best view of the neck and FD stent landing segments, PComA noticed (red arrow); (c) post-FD placement subtracted angiogram with PComA occluded (red circle); (d) post-FD placement un-subtracted angiogram; (e) single-shot X-ray showing the FD stent and previously placed coils; (f) 6-month follow-up angiogram showing mild in-stent stenosis likely from intimal hyperplasia (yellow arrow); (i) 3-year follow-up angiogram showing complete resolution of the in-stent stenosis (double arrow)

Case 9.14 Recanalization of a Thrombosed FD-Treated Aneurysm

Case Pearls

• 1. Recurrence after obliteration of the aneurysm by FD treatment is rare.

• 2. The branching point aneurysm has a higher chance of recurrence.

• 3. For large branch point aneurysms, such as fetal PCA, SAC may be a better option than FD.

(a) 3D angiogram showing a wide-neck right PComaA aneurysm with involvement of takeoff of PComA into the neck; (b, c) two views of angiogram immediately post-PED (4.5x20) placement, inserts showing well-opened PED stent; (d, e) 6-month follow-up angiogram showing faint contrast filling with patent PComA (asprin continued, Plavix stayed on for 3 months); (f) posterior circulation angiogram showing PComA/PCA is fetal type; (g–i) 18-month follow-up angiogram including 3D angiogram (g) showed significant recanalization of the previously thrombosed aneurysm

Case 9.15 Microwire “Sphere” Technique for FD Device Deployment

Case Pearls

• 1. Not fully expanded stent with endoleak is commonly seen for FD device deployment.

• 2. Balloon is commonly used for expanding the not fully opened stent.

• 3. “Sphere” technique: the microwire is shaped to form a multiple-loops sphere with a diameter greater than the stent size. The back/forth and rotational movement of the microwire pushes the “sphere” to expand the FD stent. The microcatheter can be advanced over looped wire to enhance the force of the microwire “sphere”.

(a) pre-embo 3D angiogram showing a recurrent wide-neck aneurysm of previously coiled ruptured PComA aneurysm; (b, c) pre-embo 2D views for good visualization of landing zones of the FD stent; (d) microwire shaped to form a “sphere” to open the proximal part in the ectatic cavernous ICA; (e) well-expanded proximal part of FD stent; (f) final run showed good apposition of the FD stent to cavernous ICA wall

Case 9.16 Severe In-Stent Stenosis vs Vasa Vasorum and Rare Type of Endoleak

Case Pearls

• 1. Complete FD stent occlusion is not common and new generated vascular trabecular canal after occlusion versus severe irregular stenosis is seen in this case.

• 2. Endoleak can occur even if initial wall apposition is good, likely from the result of the severe stent stenosis or occlusion.

• 3. Ophthalmic artery flow from endoleak is rare.

(a, b) Pre-embo 3D, unruptured, multilobe wide-neck right paraclinoid ICA aneurysm; (c) right ICA and left ICA angiogram showing no physiological AComA flow; (d) pre-embo 2D angiogram; (e) un-subtracted angiogram after FD stent placement, good wall supposition noticed; (f) single-shot X-ray showing the FD stent; (g–i) 6-month follow-up. AP (g), lateral (h), and left ICA angiogram (i), severe in-stent stenosis vs occlusion with vasa vasorum vessel inside occlusion noticed. It looks like that endoleak from the proximal end provides flow to ophthalmic artery. Right MCA was supplied mainly by contralateral collateral flow through AComA. Inserts showing the relationship of stent (dotted line) with the intra-stent flow and endoleak flow (arrow); (j–l) 22-month follow-up showing slightly worsening of the intra-stent flow and persistent endoleak flow; (m–o) 3-year follow-up angiogram showing significant intra-stent flow improvement noticed and also increased endoleak flow to ophthalmic artery; the AComA collateral flow to right MCA is less than what is seen in previous angiogram; (p) MRA with contrast confirmed the endoleak flow is outside stent and continuous (square dotted line) to the ophthalmic artery

Case 9.17 Two-Stage Strategy for Ruptured Wide-Neck Aneurysm

Case Pearls

• 1. Two-stage strategy for ruptured wide-neck aneurysm is preferred by many providers.

• 2. If there is any unfavorable anatomy for complete occlusion of the aneurysm, quick and simple coiling of dome to secure rupture site, then definitive treatment when recovered from SAH is recommended.

• 3. FD stent is widely used for treating neck residual/recurrence.

• 4. For persistent neck residual after FD stent embolization, is second PED needed?

(a, b) Presenting MRI and CT with SAH and ischemic stroke for acute stroke work-up; (c, d) pre-embo angiograms showing a wide-neck paraclinoid ICA aneurysm and diffuse vasospasm, which was improved after treatment; (e) pre-embo 3D, wide-neck paraclinoid ICA aneurysm; (f) pre-embo 2D views; (g) placement first coil, insert: coil contour; (h) final run post-coiling; the dome was protected, insert: coil contour; (i) 8-month follow-up angiogram showing slightly increased neck residual; (j, k) FD stent placement; (l) 19 months from FD placement follow-up angiogram; (m) 31-month MRA follow-up showing stable neck residual

Case 9.18 Intrasaccular Diverter for Bifurcation Aneurysms

Case Pearls

• 1. Appropriate sizing is the key point for the successful WEB device embolization.

• 2. The size selection is the combination of sizing chart, aneurysm morphology, and experience.

• 3. Concaved proximal end of WEB device is not recurrence or residual according to the WEB device-specific classification of result.

(a) Pre-embo 3D, dome/neck ratio ≈1; (b) pre-embo 2D working view; the takeoff of both PCA incorporating into the neck of the aneurysm; (c, d) 6×3 SL WEB device placed and is undersized with neck residual and fundus contrast filling; (e, f) 7×3 SL WEB device is perfect for the aneurysm, with no contrast filling of fundus and no neck residual; (g) un-subtracted image showing the final shape of WEB device in place; (h, i) 1-year follow-up, no recurrence, but proximal end became more concaved; (j) single-shot X-ray showing the shape of WEB device