Summary
We report a series of coil embolizations for small aneurysms solely using GDC ultrasoft coils and discuss the advantages of this method. Seven small aneurysms (<4.0 mm) were embolized solely with ultrasoft coils. Ultrasoft coils were sequentially inserted into aneurysms. Immediately after embolization, five aneurysms were completely occluded, and two exhibited body filling. All cases were treated successfully without any complications. In conclusion, ultrasoft coils were found efficacious for the treatment of small, irregular-shaped, and ruptured aneurysms; their softness and malleability facilitated their compaction into an aneurysm.
Key words: coil embolization, cerebral aneurysm, ultrasoft coil
Introduction
The endovascular treatment of intracranial aneurysms with Guglielmi detachable coils (GDC; Boston Scientific, Fremont, CA) has become widely accepted as a safe and less invasive alterative to standard surgical clipping1. However, using this method for small aneurysms still has a greater risk of rupture during coil embolization than it does for large ones. GDC-10 ultrasoft coils are the softest coils currently available for embolization of cerebral aneurysms. We report our experience of coil embolization for small aneurysms less than 4.0 mm solely using ultrasoft coils.
Material and Methods
Cases
Five consecutive patients with a total of seven aneurysms were treated solely with ultracoils in our institution (table 1). Two were ruptured aneurysms; three were unruptured aneurysms associated with ruptured aneurysms; and two were incidentally found. These aneurysms ranged from 2.5 mm to 4 mm in diameter; their locations were: two at the basilar-superior cerebellar artery (BA-SCA); one at the anterior communicating artery (Acom); one at the basilar artery (BA tip); one at the internal carotid artery (IC); one at the posterior inferior cerebellar artery (PICA distal); and one at the middle cerebral artery (MCA).
Table 1.
Summary of Cases.
| Case | Location | Symptoms | Procedure | Result | Retreatment |
|---|---|---|---|---|---|
| 1 | Acom | SAH (non ruptured) | simple technique | dome filling | + |
| IC | SAH (non ruptured) | simple technique | complete occlusion | _ | |
| 2 | PICA distal | SAH (ruptured) | simple technique | complete occlusion | + |
| 3 | BA-SCA | SAH (ruptured) | simple technique | dome filling | _ |
| 4 | BA-SCA | SAH (non ruptured) | simple technique | complete occlusion | _ |
| 5 | BA tip | incidental | remodelling technique | complete occlusion | _ |
| MCA | incidental | simple technique | complete occlusion | _ | |
Method of Coil Embolization
In this series, we solely used GDC-10 ultrasoft coils, and remodeling was achieved with a balloon, if necessary2. We sequentially inserted ultrasoft coils into the aneurysm until dense packing was achieved. Angiographic results were categorized as follows: complete occlusion; neck remnant; and body filling.
Results
All cases were successfully treated without any complications. Immediately following embolization, five aneurysms were completely oceluded, and two exhibited body filling. The remodeling technique was necessary in one case of an asymptomatie BA aneurysm. Two patients received a repeat procedure. One was an Acom aneurysm, which resulted in body filling after the initial treatment. The other was a PICA distal aneurysm, which resulted in complete occlusion at the initial treatment.
Representative Cases
Case 2
A 52-year-old man with subarachnoid haemorrhage (SAH) due to a ruptured PICA distal aneurysm was treated with coil embolization. Complete occlusion was achieved with a 2 mm x 6 cm and a 2 mm x 4 cm ultrasoft coil, preserving the vermian branch of the PICA (figure 1A,B). However, five months after treatment, the aneurysm was found to be recanalized. The recurrent portion of the aneurysm, including the vermian branch of the PICA, was packed with a 2 mm x 3 cm coil, because it was perfused in retrograde fashion after temporary occlusion at its origin (figure 1C,D).
Figure 1.
Angiogram of the vertebral artery (Case 2). A) Pre-treatment, showing the PICA distal aneurysm. B) Immediately after treatment, showing complete occlusion. C) Five months after the initial treatment, showing recanalizaton of the aneurysm. D) Post-retreatment, showing disappearance of the aneurysm including the vermian branch of the PICA.
Case 5
A 39-year-old woman received treatment for incidental multiple aneurysms. Initially, the BA tip aneurysm was embolized with a 3 mm × 8 cm and a 3 mm × 6 cm ultrasoft coil, using a remodeling technique (figure 2A,B). Subsequently, the MCA aneurysm was packed with a 2.5 mm × 6 cm and a 2.5 mm × 4 cm ultrasoft coil. In similar fashion, the aneurysm was thoroughly embolized.
Figure 2.
Angiogram of the basilar artery Case 5. A) Pretreatment, showing the BA tip aneurysm. B) Post-treatment, showing complete occlusion.
Discussion
Piecemeal Technique Compared to Standard Technique
In the standard technique, the tip of a microcatheter is placed in the center of an aneurysm. Then, a frame is made within the aneurysm using a coil as large as the aneurysm. Subsequently, coils of incrementally decreased size are introduced within the frame to fill the aneurysmal lumen.
In the "piecemeal technique" used in this series, a tip of a microcatheter is placed deeply in the dome, and an initial coil is compacted into the bottom of the aneurysm. The next coil is compacted proximal to the former coil. This method is repeated until dense packing is achieved.
Advantages of the Piecemeal Technique Using Ultrasoft Coils
For small, irregular-shaped, and ruptured aneurysms less than 4.0 mm, GDC-10 soft coils are too rigid to fit into an aneurysm and have a risk of rupture because of stress to the aneurysmal wall. Conversely, GDC-10 ultrasoft coils are about 1.5 times softer than GDC-10 soft coils; thus, facilitating compaction into an aneurysm with minimum stress.
Moreover, in a silicone sidewall aneurysm model, a 40% packing ratio (volume of coils/aneurysm volume) was achieved, solely using ultrasoft coils, compared to a 33% packing ratio with a combination of GDC-10 standard, GDC-10 soft, and GDC-10 ultrasoft coil3,4. Therefore, the safe and thorough embolization of small aneurysms can be accomplished with the sole use of ultrasoft coils.
Conclusions
In this series, we embolized small aneurysms safely and thoroughly with the sole use of ultrasoft coils. Ultrasoft coils were found to be useful for the "piecemeal technique".
References
- 1.Raymond J, Roy D, et al. Safety and efficacy of endovascular treatment of acutely ruptured aneurysms. Neurosurgery. 1997;41:1235–1245. doi: 10.1097/00006123-199712000-00002. [DOI] [PubMed] [Google Scholar]
- 2.Moret J, Cognard C, et al. La technique de reconstruction dans le traitement des aneurisms intracraniens a collet large. Resultant angiographiques et cliniques a long terme. A propos de 56 cas. J Neuroradiol. 1997;24:30–44. [PubMed] [Google Scholar]
- 3.Piotin M, Liebig T, et al. Increasing the packing of small aneurysms with soft coils: an in vitro study. Neuroradiology. 2004;46:935–939. doi: 10.1007/s00234-004-1264-5. [DOI] [PubMed] [Google Scholar]
- 4.Piotin M, Mandai S, et al. Dense packing of cerebral aneurysms: an in vitro study with detachable platinum coils. Am J Neuroradiol. 2000;21:757–760. [PMC free article] [PubMed] [Google Scholar]