Elsevier

World Neurosurgery

Volume 107, November 2017, Pages 211-215
World Neurosurgery

Original Article
The Relationship Between the Direction of Putaminal Intracerebral Hemorrhage and Anterior Cerebral Artery Predominance

https://doi.org/10.1016/j.wneu.2017.07.169Get rights and content

Objective

It is expected that anatomic variations in the circle of Willis have a direct effect on blood flow in the internal carotid artery. Rupture of the lenticulostriate artery of the middle cerebral artery 1st segment (M1) is the most common cause of putaminal intracerebral hemorrhage (ICH), and we hypothesized that this could be related to the anatomic variations of the circle of Willis and the predominance of the anterior cerebral artery 1st segment (A1).

Methods

We retrospectively reviewed the records of 544 patients who were treated for spontaneous ICH between 2013 and 2016 at Yeungnam University Hospital. Among them, 83 patients (49 men and 34 women; mean age, 60.38 years; range, 34–87 years) were admitted for the treatment of putaminal ICH. The circle of Willis was visualized on the basis of computed tomographic (CT) angiographic images with 3-dimensional (3D) reconstruction images. The number of putaminal ICH patients who showed differences in diameter between the right and left A1 segments, with a normal variation of the anterior cerebral artery (ACA), was analyzed.

Results

Among 83 patients with spontaneous ICH, 46 and 37 had left and right putaminal hemorrhages, respectively. Sixty-seven patients were treated conservatively, and 16 patients underwent surgery. The number of patients with a dominant A1 segment on either side was 58 (67.4%). Forty patients had a dominant A1 segment and putaminal ICH located in the same direction (P = 0.007).

Conclusion

It was concluded that putaminal ICHs occur more frequently on the side of the dominant A1 segment. This information can help an understanding of the mechanism of putaminal spontaneous ICH development and may even assist in the treatment of ICH.

Introduction

Intracerebral hemorrhage (ICH) is the most disabling form of stroke. It is a serious public health issue, leading to high rates of death and disability in adults. The annual incidence of ICH is 10 to 30 per 100,000 population.1, 2 ICH may be caused by trauma or may occur spontaneously. Patients with spontaneous ICH typically show hemorrhages in various locations of the brain, particularly the putamen, thalamus, subcortex, pons, and caudate nucleus. Most of these hemorrhages are due to hypertension as a result of ruptured vessels affected by hypertension-related degenerative changes or cerebral amyloid angiopathy.2 Long-standing, poorly controlled hypertension leads to a rupture in the cerebral vessels, such as the lenticulostriate artery of the middle cerebral artery (MCA) or the thalamoperforating artery of the posterior cerebral artery (PCA). Endovascular pressure is directly or indirectly associated with the volume of cerebral blood. In this respect, determination of blood flow (in milliliters per minute) in the intracerebral vessels has been used to evaluate cerebral hemodynamic stress in patients with spontaneous ICH.3, 4

It can be expected that variations in the anatomy of the circle of Willis affect the determination of blood flow in the major feeding arteries of the brain. Generally, the anatomy of the circle of Willis shows no variations, such that the internal carotid arteries (ICAs) distribute flow into the ipsilateral anterior cerebral artery (ACA) and MCA, whereas the basilar artery (BA) distributes flow into both PCAs. However, the results of several studies have shown that up to 50% of healthy control individuals have an anatomic variant of the circle of Willis, such as a missing A1 segment of the ACA or a fetal-type PCA. It is expected that these variations have a direct effect on blood flow in the ICAs and BA.5, 6, 7

This study aimed to retrospectively determine the effect of anatomic variations in the circle of Willis, in terms of circulation, on the cerebral blood flow and direction of putaminal ICH.

Section snippets

Materials and Methods

To determine the correlation between the direction of spontaneous ICH and A1 predominance, we retrospectively reviewed the records of all patients who were treated for spontaneous ICH between 2013 and 2016 at our hospital. The inclusion criteria for the patients in this study included the following: brain computed tomography (CT) scan showing a spontaneous putaminal ICH with no traumatic bleeding, and no vascular abnormality in 3-dimensional (3D) reconstruction images. Thalamic, subcortical,

Results

All patients had a putaminal ICH on the unilateral side. Among 83 patients (49 men and 34 women), 46 of the spontaneous putaminal ICHs were on the left and 37 were on the right. The mean age of the patients was 60.38 years (range, 34–87) years. Sixty-seven patients were treated conservatively, and 16 patients underwent decompressive craniectomy or stereotactic catheter placement for hematoma drainage. Of the 83 patients with a spontaneous putaminal ICH, 58 (67.4%) had a dominant A1 segment,

ACA Variation

An incomplete circle of Willis is frequently observed on conventional cerebral angiograms or CT angiograms. There are several types of ACA variation: bihemispheric (asymmetric) ACA, triple ACA, and unpaired (azygous) ACA. Bihemispheric ACA is constituted by a pericallosal artery supplying the medial portions of both hemispheres.8 This variation is found in 2% to 7% of anatomic specimens. Several terms have been used for the triple ACA, including accessory ACA, the median artery of the corpus

Conclusion

In our study, it was concluded that putaminal ICHs occur more frequently on the side of the dominant A1 segment. This information can help in an understanding of the mechanism of putaminal spontaneous ICH development and may even assist in the treatment of ICH.

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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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