Elsevier

World Neurosurgery

Volume 89, May 2016, Pages 309-319
World Neurosurgery

Original Article
The Microsurgical Anatomy of the Orbitofrontal Arteries

https://doi.org/10.1016/j.wneu.2016.02.024Get rights and content

Objective

The orbitofrontal (or frontobasal) arteries (OFAs) are the medial (MOFA) and lateral (LOFA) orbitofrontal artery, branches of the anterior and middle cerebral artery, respectively. They supply the orbitofrontal cortex. The purpose of this microscopic cadaveric study was the detailed and precise anatomic identification of the OFAs along their course.

Methods

Twenty formalin-fixed, colored latex-injected cadaveric heads were studied with the aid of an operating microscope and microsurgical instrumentation. The anatomy of the OFAs was examined after removing the cerebrum from the cranial vault. Anatomic features of the MOFA and LOFA were investigated and assessed in relation to demographic and anthropometric variables.

Results

The MOFA supplies approximately 15 branches and LOFA almost 16 branches. The MOFA provides 1 branch to the olfactory bulb and 4 branches to the olfactory tract, and there are approximately 2 MOFA-LOFA anastomoses per hemisphere (novel finding). The MOFA origin is located approximately 7.9 mm anterior to the anterior communicating artery and 4.7 cm posterior to the anterior limit of the gyrus rectus. The LOFA origin is located approximately 11.1 mm from the middle cerebral artery bifurcation. Younger, shorter, and lighter individuals have more MOFA-LOFA anastomoses. Finally, the number of MOFA branches for the olfactory bulb is positively correlated with the number of MOFA branches for the olfactory tract, as well as with the number of MOFA-LOFA anastomoses.

Conclusions

The present study provides a detailed description of the OFAs' microsurgical anatomy and can help neurosurgeons to easily identify, manipulate, and preserve these vessels during surgery.

Introduction

The orbitofrontal (or frontobasal) arteries (OFAs) consist of the medial (MOFA) and lateral (LOFA) orbitofrontal arteries. The MOFA is usually the first branch of the A2 segment of the anterior cerebral artery (ACA) and is distributed to the gyrus rectus and medial orbital gyri. The LOFA most frequently branches off the superior (frontal) trunk of the middle cerebral artery (MCA) (M2 segment) and irrigates the lateral orbital gyri.1, 2

Although the OFAs supply the orbital gyri giving rise to many perforators, the arterial vascularization pattern of the orbitofrontal cortex varies significantly. Hence, issues regarding the microsurgical anatomy of the OFAs arise in terms of their respective emerging pattern, distribution area, branching configuration, anastomoses, and the possible anatomic landmarks aiding in their intraoperative identification.

Therefore, the purpose of this microscopic cadaveric study was to address these topics and assess the relation of the OFAs to major neurovascular structures of the frontal base, namely the anterior communicating artery complex (ACoA), the olfactory tract and bulb, and the MCA bifurcation. Anatomic features (branching, length, and anastomoses) of the OFAs were assessed in relation to demographic and anthropometric variables.

Section snippets

Materials

Twenty formalin-fixed, colored latex-injected human cadaveric heads (8 men and 12 women), preserved in a solution of ethyl alcohol (10%), were studied. Their average age was 71.50 ± 13.75 years (range, 38–95 years), height 166.49 ± 11.05 cm (range, 152.40–187.96 cm), weight 65.10 ± 19.77 kg (range, 37.19–115.67 kg), and body mass index 23.77 ± 5.73 kg/m2 (range, 14.29–37.12 kg/m2). Microsurgical instruments and the operating microscope (Carl Zeiss Meditec AG OPMI pico, Oberkochen, Germany) were

Microsurgical Study

During microsurgical dissection, we observed that the MOFA origin (A2 segment) is usually found medially to the gyrus rectus (particularly at its proximal part). Consequently, its access necessitates dissection of the interhemispheric fissure toward the ACoA complex. Slight manipulation of the olfactory tract aids in exposing the MOFA, especially when it lies between the olfactory tact and the orbitofrontal cortex.

During Sylvian fissure dissection to expose the LOFA origin (emerging from M1 or

MOFA: Origin

Our results demonstrate a remarkable variability in the origin of the MOFA, usually located 8 mm anterior to the ACoA complex and almost 5 cm posterior to the anterior limit of the gyrus rectus. Rarely (3% of cases) it was found along the A1 segment of the ACA. The fact that the distance between the MOFA origin and the anterior limit of the gyrus rectus is greater in male, taller, and heavier individuals, is expected as bigger individuals tend to have larger brains.

The MOFA is the first

Conclusions

The MOFA origin is typically located 8 mm anterior to the ACoA and almost 5 cm posterior to the anterior limit of the gyrus rectus. It is the principal supplier of the olfactory tract and bulb and can rarely be the site of interhemispheric arterial anastomosis. The ACoA complex, gyrus rectus, and olfactory sulcus, tract, and bulb are important landmarks for the intraoperative identification of the MOFA and its branches, and for distinguishing it from RAH.

The LOFA origin is found 9.4 mm distal

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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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