J Cerebrovasc Endovasc Neurosurg.  2019 Dec;21(4):193-198. 10.7461/jcen.2019.21.4.193.

A new definition for wide-necked cerebral aneurysms

• Park HS
• Kwon SC
• Park ES
• Park JB
• Kim MS

• KMID: 2468182
• DOI: http://doi.org/10.7461/jcen.2019.21.4.193

Abstract

BACKGROUND
Endovascular management of wide-necked aneurysms often requires assisted-techniques with adjunctive devices. Wide-necked aneurysm can be defined with a dome-to-neck ratio or aspect ratio; however, clinical definitions of wide-necked aneurysms vary. This study aimed to determine the most useful definition of wide-necked aneurysm to predict the need for an adjunctive device.
METHODS
Among 552 cases of aneurysms, 343 (62.1%) and 209 (37.9%) cases of unruptured and ruptured aneurysms, respectively, were treated in a single institution. For each aneurysm, the (1) dome-to-neck ratio, (2) aspect ratio, and (3) K-ratio (defined as [dome height+maximum dome width]/[2×maximum neck width]) were measured. We statistically analyzed patient data to determine which of the three ratios was most predictive of the need for adjunctive devices.
RESULTS
Among 552 cases of aneurysms, 277 (50.2%) and 275 (49.8%) cases were treated with and without adjunctive techniques, respectively. The mean dome-to-neck ratio, aspect ratio, and K-ratio were 1.17±0.39, 1.58±0.61, and 1.37±0.47, respectively. The K-ratio was the strongest predictor of the use of adjunctive devices (P<0.001), and 1.3 was the most appropriate K-ratio cut-off value (sensitivity, 72.9%; specificity, 63.6%).
CONCLUSIONS
K-ratio was the most useful predictor of the need for adjunctive devices in the treatment of endovascular aneurysms. These results suggest that the K-ratio may be used to define wide-necked aneurysms requiring complicated management via adjunctive devices.

Keyword

Intracranial aneurysm; Endovascular treatment; Wide-necked aneurysm; Definition

MeSH Terms

Aneurysm
Aneurysm, Ruptured
Humans
Intracranial Aneurysm*
Neck
Sensitivity and Specificity

Figure

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  Fig. 1 Definitions of wide-necked cerebral aneurysm.

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  Fig. 2 Reference values of the dome-to-neck ratio (1.0), aspect ratio (1.4), and K-ratio (1.3).

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  Fig. 3 In cases where the maximum dome width is the neck width (cone or rod shape), (A) treatment with the coil alone may not cover the aneurysm neck, or the coil is likely to protrude into the parent artery (B). In such cases, embolization with a stent will allow for successful treatment (C).

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  Fig. 4 If the height of the aneurysm dome is small (A) but the maximum width of the dome is sufficiently larger than the neck width, the coil alone can be used to complete the treatment (B).

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