Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 55, Num. 2, 2007, pp. 148-150

Neurology India, Vol. 55, No. 2, April-June, 2007, pp. 148-150

Case Report

Spontaneous extrusion of guglielmi detachable coils from anterior communicating artery aneurysm

Choudhari KishorA, Flynn PeterA, McKinstry StevenC

Department of Neurosurgery, Regional Neurosciences Unit, Royal Victoria Hospital, Belfast BT12 6BA
Correspondence Address:Department of Neurosurgery, Regional Neurosciences Unit, Royal Victoria Hospital, Belfast BT12 6BA kchoudhari@hotmail.com

Date of Acceptance: 15-Jan-2007

Code Number: ni07053

Abstract

Keywords: Anterior communicating artery aneurysm, aneurysm embolization, extrusion of coils, guglielmi detachable coils

Introduction

Case Report

Discussion

After ISAT, most ruptured aneurysms in the region of the anterior communicating artery are primarily offered endovascular intervention. Thromboembolic episodes at the time of coiling and delayed coil compaction in the dome of the aneurysm are probably the two most common complications associated with GDC embolization.[2],[3] While the former are mostly self-limiting, the precise significance of coil compaction is not known. Most recent series, however, indicate that the actual re-bleeding rate subsequent to re-growth at the neck and/or coil compaction is small.[4] Perhaps, significant recurrences are diagnosed at the time of radiological follow-up and are treated in a timely fashion before re-rupture occurs.

The interventionalists are familiar with coil protrusion in the parent vessel lumen,[5] occasional distal migration of inadvertently detached coil and minor peri-procedural embolic events that often require short-term anticoagulation. While delayed coil compaction is frequent, complete extrusion of the coil mass out of the aneurysmal confines is rare. The likely mechanism seems to be progressive coil compaction into the dome. If the original aneurysm is thin-walled, the coil mass is gradually pushed through the dome by "water-hammer" effect of the blood flow. Although the exact incidence of neck re-growth resulting from coil compaction is quoted to be as high as 35% in some studies,[4] such extreme compaction leading to complete expulsion of the coils from the aneurysm lumen and subsequent re-bleeding is fortunately rare. This, however, poses a dilemma for the neurovascular team as to at what stage of recurrence should aneurysms be treated and which is the best modality of treatment. In our case, there was early and progressive recanalization of the aneurysm almost to the pretreatment size and the patient was young. All these factors swayed our decision towards early surgical intervention without waiting further, as the cumulative risk of re-bleed was thought to be significant.

Most of the coil loops had migrated outside the aneurysmal wall lying in the arachnoid space, the dome being flimsily sealed by the base of the coil mass. The aneurysm had not healed as one would have hoped after satisfactory coiling. At surgery, it appeared that the coil mass had simply migrated through the dome of the aneurysm due to the water-hammer effect of blood flow. There was minimal fibrous or thrombogenic reaction around the coils that were bathing freely in the CSF. Although subsequent rupture was imminent from these operative findings, the patient did not have sentinel headaches to suggest minor leaks. Dissection of the neck and clipping was as straightforward as that in unruptured aneurysms as the coils had moved distally making reasonable neck and body to facilitate satisfactory clipping. Formation of another small satellite aneurysm was unrelated to coil expulsion, but confirmed an ongoing biological process of active aneurysm formation that was not halted by seemingly satisfactory embolization of the primary aneurysm.

This case emphasizes the importance of careful long-term radiological follow-up of small coiled aneurysms.[3] We do not have a rigid protocol for follow-up of coiled aneurysms. Most cases, however, undergo an MRI/MRA after six months and a DSA after a year following initial coiling. Further radiological follow-up is decided by the results of these investigations on the individual merits of the case. Unfortunately, precise natural history of small neck-remnants and minor coil-compaction remains elusive. Asymptomatic spontaneous coil extrusion as seen in our patient may perhaps be more common than the literature suggests and is likely to be encountered more frequently in future as we continue to embrace the endovascular means of treatment for ruptured aneurysms. Surface modification technology allowing protein-coated platinum is promising to enhance adhesiveness and reduce distal coil migration.[6] From our experience and available literature data, we advocate early re-treatment of aneurysms with coil-extrusion.[7],[8] As this phenomenon seems uncommon and unpredictable, each case of minor coil compaction needs to be followed up and managed on its individual merits. Nevertheless, whether spontaneous extrusion of coil mass from the aneurysm is simply a progression in the natural history and whether it indeed increases the risk of subsequent re-bleed remains unclear at this stage.

References

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