J Korean Neurosurg Soc.  2021 Jan;64(1):39-50. 10.3340/jkns.2020.0028.

Clinical Outcomes of Large (>10 mm) Unruptured Posterior Circulation Aneurysms and Their Predictors

• Byun J
• Park W
• Park JC
• Ahn JS

• KMID: 2510758
• DOI: http://doi.org/10.3340/jkns.2020.0028

Abstract

Objective
: The treatment of large aneurysms of the posterior circulation is complicated and remains challenging. We here analyzed our institutional clinical outcomes of large unruptured aneurysms of the posterior circulation.
Methods
: This study included 56 patients who presented with a large (>10 mm) unruptured aneurysm of the posterior circulation between 2002 and 2018.
Results
: There were 18 (32.1%) male and 38 (67.9%) female patients, with a mean age of 53.4 years. The most common location was the vertebral artery, followed by the basilar tip and posterior cerebral artery. The median follow-up duration was 29 months. Eighteen patients (32.1%) were treated by transcranial surgery and 38 (67.9%) were treated by endovascular treatment (EVT). Posttreatment complications occurred in 16 patients (28.6%), with there being no significant difference between the transcranial surgery and EVT groups. Complete obliteration was achieved in 30 patients (53.6%), with there being no statistically significant difference between the transcranial surgery and EVT groups. Recurrence occurred in 17 patients (30.4%), and the rate of recurrence was higher in the EVT group than in the transcranial surgery group (39.5% vs. 11.1%, p=0.03). Forty-four (84%) of 56 patients showed a favorable functional outcome. In saccular aneurysm, EVT was negative predictor of worsening of functional status.
Conclusion
: Treatment of these aneurysms harbors an inherent high risk of morbidity. No superiority was found between transcranial surgery and EVT in terms of complications and complete obliteration, but transcranial surgery showed a higher treatment durability than EVT.

Keyword

Aneurysm, Large, Unruptured; Surgery; Treatment outcome; Complications; Posterior circulation

Figure

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  Fig. 1. Patient enrollment. A total of 56 patients who presented with a large unruptured posterior circulation aneurysm between January 2002 and December 2018 were enrolled. AVM : arteriovenous malformation.

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  Fig. 2. Representative cases of large unruptured posterior circulation aneurysms. A : Left vertebral artery aneurysm incorporating the posterior inferior cerebellar artery. This aneurysm was partially thrombosed and compressed the brainstem. B : Large vertebrobasilar junction aneurysm incorporating multiple perforators and the posterior inferior cerebellar artery. C : Large basilar trunk aneurysm that severely compressed the brainstem. D : Large bilobed vertebral artery aneurysm. E : Basilar tip aneurysm incorporating both posterior cerebral arteries and superior cerebellar arteries. F : Large posterior cerebral artery P3 segment aneurysm.

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  Fig. 3. Treatment of large unruptured posterior circulation aneurysms. Various treatment strategies were used for large unruptured posterior circulation aneurysms. A and D : Large basilar tip aneurysm treated by coil embolization. A large coil mass can be seen in the aneurysm. B and E : Lage bilobed vertebral artery aneurysm treated by direct clipping through the far-lateral transcondylar approach. C and F : Large partially thrombosed aneurysm that incorporated the posterior inferior cerebellar artery (PICA). An occipital artery-PICA end-to-side anastomosis (red arrow) was performed, and additional coil trapping of the left vertebral artery (blue arrow) was undertaken.

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  Fig. 4. Image findings of posttreatment complication cases. A-C : Case #5 of Table 3. A and B : Patient underwent direct clipping of large thrombosed basilar tip aneurysm. C : In postoperative CT scan, postoperative venous infarction was occurred, low density of right frontal lesion with scattered hematoma were seen. Decreased consciousness and left side motor weakness were noted, patient treated conservatively. D-F : Case #3 of Table 3. D and E : Patient underwent superficial temporal artery-superior cerebellar artery bypass with microsurgical trap of posterior cerebral artery. F : Intracerebral hemorrhage of left thalamus was seen in postoperative computed tomography scan. Right side motor weakness (grade IV) was seen, however patient recovered very well. G-I : Case #14 of Table 3. G and H : Patient underwent coil embolization with parent artery occlusion for right PCA aneurysm, patient was neurologically stable during preoperative balloon test occlusion of PCA. I : Right thalamic infarction was noted in diffusion MRI. Left side motor weakness (grade IV) was seen, however, patient recovered very well. J-L : Case #15 of Table 3. J and K : Patient underwent coil embolization and parent artery occlusion for left PCA aneurysm. L : Postoperative left PCA territory infarction was noted in diffusion MRI. Patient was neurologically stable during preoperative balloon test occlusion of PCA. Patient recovered well except visual field defect. PCA : posterior cerebral artery, MRI : magnetic resonance imaging.

Reference

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