Arterial vascularization of occipital scalp: mapping of vascular cutaneous territories and surgical applications

Vertical Levels of the Occipital Artery Origin

Background and Objectives. The occipital artery (OA) is a posterior branch of the external carotid artery (ECA). The origin of the OA is commonly referred to a single landmark. We hypothesized that the origin of the OA could be variable as referred to the hyoid bone and the gonial angle. We thus aimed at patterning the vertical topographic possibilities of the OA origin. Materials and Methods. One hundred archived computed tomography angiograms were randomly selected, inclusion and exclusion criteria were applied, and 90 files were kept (53 males, 37 females). The cases were documented bilaterally for different levels of origin of the OA origin: type 1-infrahyoid; type 2-hyoid; 3-infragonial; 4-gonial; 5-supragonial; 6-origin from the internal carotid artery (ICA). Results. The incidence of unilateral types in the 180 OAs was: type 1-1.11%, type 2-5.56%, type 3-40.56%, type 4-28.33%, type 5-23.33% and type 6, ICA origin of the OA-1.11%. There was found a significant association between the location of the left and right origins of the OAs (Pearson Chi2 = 59.18, p < 0.001), which suggests the presence of a strong symmetry of the origins. Bilateral symmetry of the vertical types of the OA origin was observed in 56.67% of cases; in 43.33% there was bilateral asymmetry. Conclusions. The ICA origin of the OA is an extremely rare variant. For surgical planning or prior to endovascular approaches the topography of the OA origin should be carefully documented, as it may be located from an infrahyoid to a supragonial level.

Are bone erosion and peripheral feeding vessels hallmarks of intracranial solitary fibrous tumor/hemangiopericytoma?

An 86-year-old man sustained progressive motor weakness in the left lower extremity for 1 month. Cranial computed tomography (CT) revealed an isodense mass in the right parietal lobe, with a smooth-contoured focal erosion in the adjacent parietal bone. The extra-axial tumor appeared isointense on T1- and hyperintense on T2-weighted magnetic resonance imaging with intense enhancement. On three-dimensional CT angiography, the ectatic left occipital artery coursed into the right parietal foramina and connected with a dilated meningeal vessel supplying the tumor. The focal erosion formed in the inner parietal bone was located adjacent to the feeding vessel. A total tumor resection was achieved. The microscopic findings of the resected specimen were consistent with a World Health Organization grade III hemangiopericytoma (HPC). Bone erosion and peripheral feeding vessels may be characteristic findings of intracranial solitary fibrous tumor (SFT)/HPC. Careful interpretation of neuroimages could help detect clues for distinguishing an SFT/HPC masquerading as a meningioma from a true meningioma.

Fetal anatomy of the facial nerve trunk and its relationship with posterior auricular artery

PURPOSE

The aims of the study are to define anatomy of the facial nerve (FN) and its main trunks as well as their relationship with the posterior auricular artery in fetal period to evaluate the data for regional surgery in newborns and young infants.

METHODS

Formalin-fixed 34 fetuses from anatomy laboratory collection with a mean gestational age of 26.4 ± 4.6 (20-36) weeks were dissected. Parameters regarding the presence of major or minor trunks, width, length, branching pattern of FN were evaluated according to side, gender and trimester. The positional relationship of posterior auricular artery with the FN trunk was inspected.

RESULTS

On all sides only the major trunk of the FN was detected. For length and width parameters, there was no statistically significant difference for side and gender except for trimester. Linear functions were found as 0.329 + 0.025 × weeks for width and 5.264 + 0.185 × weeks for length. There are statistically significant linear relationships between width and length of the FN trunk and week parameters as r = 0.507, p < 0.001 and r = 0.484, p < 0.001, respectively. Posterior auricular artery crossed FN trunk laterally in 42 of 53 sides, medially in 9 sides while it was puncturing it proximally in 2 sides. In all cases, it was in close contact to the FN trunk. FN trunk showed bifurcation in 82% and trifurcation in 18%.

CONCLUSION

Dimensions of FN trunk, growth ratio and linear functions can be beneficial in understanding the fetal growth of FN trunk and its usage for grafts. Data about the relationship of the posterior auricular artery with FN trunk may be crucial in avoiding iatrogenic injuries during surgery in early ages.

Anatomical and Histological Evaluation of the Retroauricular Fascia Flap for Staged Auricular Reconstruction

OBJECTIVES

The retroauricular fascia flap (RFF) is one of the most commonly used vascularized linings for auriculocephalic sulcus reconstruction in staged total auricular reconstruction. This study aims to investigate the histomorphometric features regarding the retroauricular fascia.

METHODS

Histological evaluation included qualitative observation and quantitative analysis of sections of RFF stained with hematoxylin and eosin, Masson's trichrome, Elastica van Gieson, CD31, and Lyve-1. Ultrasonographic evaluation included measurement of the thickness of the superficial layer of the retroauricular fascia (RFF origin) at three different positions in microtia patients. P < 0.05 was considered statistically significant.

RESULTS

RFF was a thin, highly organized layer with mainly collagen fibers. From its superior to inferior portions, the percentage of collagen fibers differed significantly (superior 87.57 ± 10.85%, middle 68.29 ± 29.02%, inferior 53.31 ± 33.33%, p < 0.05). The percentages of elastic fibers in the superior (4.86 ± 5.17%) and middle (5.05 ± 5.37%) areas were higher than that in the inferior (2.14 ± 2.42%, p < 0.05). RFF blood vessel density (20× magnification) decreased significantly from the superior to inferior portions (superior 6.39 ± 1.18, middle 5.17 ± 1.15, inferior 2.67 ± 0.78, p < 0.05). Lymphatic vessel density (20× magnification) also decreased significantly from the superior to inferior regions (superior 6.80 ± 0.62, middle 5.26 ± 1.17, inferior 2.11 ± 0.46, p < 0.05). Thickness of the superficial layer of retroauricular fascia increased significantly from the superior to inferior regions (superior 0.29 ± 0.06 mm, middle 0.36 ± 0.09 mm, inferior 0.53 ± 0.14 mm, p < 0.001).

CONCLUSIONS

From cranial to caudal, the RFF became thicker, less elastic, and less vascularized, and contained fewer lymphatic vessels. Therefore, when the retroauricular fascia is large enough, the superior portion would be preferred for RFF in auriculocephalic sulcus reconstruction.

NO LEVEL ASSIGNED

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Novel classification of the posterior auricular artery based on angiographical appearance

Purpose

To investigate the length variation of the posterior auricular artery and propose a novel classification of the posterior auricular artery based on angiographical appearance.

Patients and Methods

A series of 234 consecutive patients who had undergone conventional cerebral angiography was analyzed. The posterior auricular artery was examined on the lateral projection of the external carotid or common carotid arteriography. The posterior auricular artery was classified into four groups by length, using the external auditory canal and the top of the helix as radiographical landmarks. Our proposed classification is as follows: Type A, posterior auricular artery terminates between its origin and the center of the external auditory canal; Type B, posterior auricular artery terminates between the center of the external auditory canal and the top of the helix; Type C, posterior auricular artery terminates between the top of the helix and the vertex; and Type D, posterior auricular artery reaches up to the vertex.

Results

A total of 424 (right, 214; left, 210) posterior auricular arteries were analyzed in 111 men and 123 women aged 11 to 91 years (mean, 61.0 years) examined for aneurysms in 78 cases, occlusive vascular diseases in 56, intracranial hemorrhages in 41, tumors in 35, and others in 24. Types A, B, C, and D were found in 15.1%, 34.9%, 48.8%, and 1.2% of the patients, respectively.

Conclusion

A novel classification of the posterior auricular artery identifies four types based on its length on cerebral angiography.

[Scalp flap pedicled on the posterior auricular artery. Anatomical study and clinical application]

INTRODUCTION

Management of scalps defect is a common subject for reconstructive surgery. The use of local flap is better because of the hairy skin.

OBJECTIVE

The auricular posterior artery is often described as an accessory blood supply for the scalp.

METHOD

We present an original case of 16×6 cm scalp flap harvested almost in "vascular island" on the right retro-auricular pedicle to cover an occipital wound.

RESULTS

We have obtained an effective healing in 20 days. Despite its considerable length, no distal necrosis has occurred.

CONCLUSION

Rarely reported in the surgical literature, the posterior auricular vessels are a good blood supply to harvest scalp flap. This procedure adds to overall techniques of reconstructive surgery for scalps defects that plastic surgeons can use.