Occipital artery: Anatomical variations and neurosurgical applications

Background

The occipital artery (OA) is a branch of the external carotid artery. It gives rise to several cutaneous, muscular, and meningeal branches to supply different anatomical areas. The implication of OA in the neurosurgical field is well-established in the literature. Our aim in this study is to draw a complete picture of the anatomical variations and neurosurgical applications of the OA.

Methods

A literature review was conducted in Google Scholar and PubMed to review the studies discussing OA, its anatomical variation, and neurosurgical applications.

Results

We identified 29 articles that discuss the anatomical variations and neurosurgical applications of the OA. Certain variables are used to describe the surgical anatomy of OA. We also discussed certain applications of OA and its importance in neurosurgical bypass, embolization, and aneurysms.

Conclusion

Comprehending the anatomy of the OA is crucial for neurosurgeons to safely and effectively perform procedures such as bypass and embolization. In addition, knowledge of the anatomical variations of the OA can help surgeons anticipate potential challenges and tailor their approach accordingly.

Fully Endoscope-Controlled Clipping Ruptured Intrameatal Anterior Inferior Cerebellar Artery Aneurysm: Report of 2 Cases

ABSTRACT

Aneurysms of the anterior inferior cerebellar artery (AICA) are a rare entity. Purely intrameatal aneurysms are even rarer. The author reported 2 ruptured intrameatal aneurysms that were treated by fully endoscope-controlled clipping. Retrosigmoid craniotomy was performed and the aneurysm was clipped definitely intraoperative without postoperative deficits except hearing loss and slight facial nerve paresis. Follow-up angiography demonstrated exclusion of the aneurysm, confirming preservation of the distal aneurysms of the anterior inferior cerebellar artery. Endoscopic enhancement of the visual field provided by the endoscope may be a safe and effective application to increase the quality of treatment for intrameatal aneurysm, especially for deep aneurysm.

Minimally invasive treatment strategy for partially thrombosed anterior inferior cerebellar artery aneurysm: A case report

Background:

Partially thrombosed anterior inferior cerebellar artery (AICA) aneurysms are extremely rare; thus, no established therapeutic approach exists.

Case Description:

We report a large, partially thrombosed AICA aneurysm and discuss its therapeutic nuances. The aneurysm was asymptomatic; therefore, we aimed to treat it through a minimally invasive procedure. The aneurysm was of fusiform type and the proximal neck of the aneurysm was positioned at midline in front of the brainstem. To approach the neck, posterior transpetrosal approach is recommended. However, this approach can be invasive; thus, we performed distal clipping of the aneurysm using transcondylar fossa approach with occipital artery-AICA bypass to avoid ischemia of the AICA territory. Although the size of the aneurysm initially increased, it subsequently decreased.

Conclusion:

This is a rare case report describing the long-term clinical course after distal clipping in detail. We showed that traditional microsurgical techniques can be applied to treat patients with new, minimally invasive treatment strategies.

Anterior Inferior Cerebellar Aneurysm Treated by Aneurysm Resection and Intracranial Artery Anastomosis in situ: A Case Report and Literature Review

Background: Anterior inferior cerebellar artery (AICA) aneurysms are relatively rare in clinical practice, accounting for <1% of all intracranial arteries. After the diagnosis and location are confirmed by angiography, magnetic resonance, and other imaging examinations, interventional, or surgical treatment is often used, but some complex aneurysms require reconstructive surgery. Case Description: An 8-year-old male child was admitted to the hospital due to sudden disturbance of consciousness for 2 weeks. The head CT showed hematocele in the ventricular system with subarachnoid hemorrhage in the basilar cistern and annular cistern. On admission, he was conscious, answered correctly, had a soft neck, limb muscle strength was normal, and had no cranial nerves or nervous system abnormalities. A preoperative examination showed the right side of the anterior distal arteries class under the circular wide neck aneurysm, the distal anterior inferior cerebellar artery supplying a wide range of blood to the cerebellum, the ipsilateral posterior inferior cerebellar artery absent, and the aneurysm close to the VII, VIII nerves. The aneurysm was successfully treated by aneurysm resection and intracranial artery anastomosis in situ of a2 AICA-a2 AICA. Conclusions: AICA aneurysms are relatively rare; in this case, a complex wide-necked aneurysm was successfully treated by aneurysm resection and anastomosis in situ of a2 AICA-a2 AICA. This case can provide a reference for the surgical treatment of complex anterior cerebellar aneurysms.

Challenges in Using the Posterior Inferior Cerebellar Artery for Revascularization of the Anterior Inferior Cerebellar Artery: A Microsurgical Anatomic Study

BACKGROUND

A bypass is usually required to prevent ischemia during the treatment of anterior inferior cerebellar artery (AICA) aneurysms. The intracranial (IC)-to-IC bypass provides several advantages over the extracranial-to-IC bypass in the posterior fossa. However, there are only 2 case reports about AICA revascularization with the posterior inferior cerebellar artery (PICA). We aimed to investigate the microsurgical anatomical challenges for PICA to AICA anastomosis.

METHODS

Ten cadaveric heads injected with colored silicone were inspected on both sides using a lateral transcondylar approach. After the donor and recipient arteries were examined from the posterior side, neurovascular contents of the posterior fossa were excised and the origin, course, and variations of both arteries were investigated from the anterior view. The diameters of the AICA and PICA segments and the intersegment distance were measured.

RESULTS

PICA variations and posteromedial origins from the vertebral artery were identified in 8 of the 20 right and 6 of the 20 left sides, and the first segment of the PICA was not present in 7 sides. Furthermore, in 18 sides, the PICA was trapped between the lower cranial nerves and dentate ligaments. Therefore the donor artery could not be brought closer than 1 cm to the recipient artery in 19 sides. Moreover, AICA variations were identified in 6 sides, and in 12 sides, the diameter of the recipient artery was <1 mm.

CONCLUSIONS

The mostly PICA-related issues made PICA-to-AICA anastomosis unfeasible in all cadaveric heads included in the study.

Cerebrovascular bypass for ruptured aneurysms: A case series

In patients with aneurysmal subarachnoid hemorrhage (aSAH) unfavorable for endovascular or traditional open surgical techniques, surgical revascularization strategies comprise one of remaining limited options. There is nonetheless a paucity of data on the safety and efficacy of bypass in aSAH. In this study, we aimed to investigate complications and outcomes in a cohort of patients with aSAH treated with bypass. A prospective single-surgeon database of consecutive patients treated for aSAH between 2013 and 2018 was retrospectively analyzed. Complications and functional status at discharge were recorded and analyzed for the patients that underwent bypass surgery. Forty patients with aSAH were treated with bypass surgery (23 extracranial-intracranial; 17 intracranial-intracranial). All-cause perioperative mortality was 13% (6 patients). At discharge and at mean 14-month follow up, respectively, 16/40 (40%) and 16/25 (64%) of patients achieved a Glasgow Outcome Score of 4-5. All-cause, in-hospital complications occurred in 28 patients (70%), of which any ischemic complication occurred in 20 patients (50%), 7 (18%) being open surgical complications. This work represents the largest modern series of bypass for aSAH to date. In cases of aSAH unfavorable for endovascular intervention or traditional open surgical techniques, bypass remains a viable option in this complex group of patients.

[Anatomical bases of brain revascularization: choosing an extra-intracranial bypass option]

Surgical brain revascularization is an important treatment for acute or chronic ischemia, intracranial aneurysms and skull base tumors. Individual anatomy of brain vessels should be clearly understood for this procedure. Variants of collateral cerebral blood flow in patients with cerebrovascular diseases depend on individual characteristics of circle of Willis and reserve mechanisms of collateral circulation. These anatomical variations require careful preoperative planning to choose the optimal revascularization option.

An a3-Anterior Inferior Cerebellar Artery to p3-Posterior Inferior Cerebellar Artery Bypass With Thrombectomy and Trapping of an Anterior Inferior Cerebellar Artery Aneurysm: 3-Dimensional Operative Video

In situ bypasses to the anterior inferior cerebellar artery (AICA) are unusual because, with only one artery in the cerebellopontine angle (CPA), no natural intracranial donors parallel its course. In rare cases, the posterior inferior cerebellar artery (PICA) may have the tortuosity or redundancy to be mobilized to the AICA to serve as a donor. This video demonstrates this p3 PICA-to-a3 AICA in situ side-to-side bypass. A 75-yr-old woman presented with ataxia and hemiparesis from a large thrombotic right AICA aneurysm compressing the brainstem. Strategy consisted of bypass, trapping, and brainstem decompression. Written informed consent for surgery was obtained from the patient. A hockey-stick incision was made to harvest the occipital artery as a backup donor, but its diminutive caliber precluded its use. The bypass was performed through an extended retrosigmoid craniotomy. The aneurysm was trapped completely and thrombectomized to relieve the pontine mass effect. Indocyanine green videoangiography confirmed patency of the bypass, retrograde filling of the AICA to supply pontine perforators, and no residual aneurysmal filling. This unusual in situ bypass is possible when redundancy of the AICA and PICA allow their approximation in the CPA. The anastomosis is performed lateral to the lower cranial nerves in a relatively open and superficial plane. The extended retrosigmoid approach provides adequate exposure for both the bypass and aneurysm trapping. In situ AICA-PICA bypass enables anterograde and retrograde AICA revascularization with side-to-side anastomosis. The occipital artery-to-AICA bypass and the V3 vertebral artery-to-AICA interpositional bypass are alternatives when intracranial anatomy is unfavorable for this in situ bypass.1-6 Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Revascularization of the Posterior Inferior Cerebellar Artery Using the Occipital Artery: A Cadaveric Study Comparing the p3 and p1 Recipient Sites

BACKGROUND

Revascularization of the posterior inferior cerebellar artery (PICA) is typically performed with the occipital artery (OA) as an extracranial donor. The p3 segment is the most accessible recipient site for OA-PICA bypass at its caudal loop inferior to the cerebellar tonsil, but this site may be absent or hidden due to a high-riding location.

OBJECTIVE

To test our hypothesis that freeing p1 PICA from its origin, transposing the recipient into a shallower position, and performing OA-p1 PICA bypass with an end-to-end anastomosis would facilitate this bypass.

METHODS

The OA was harvested, and a far lateral craniotomy was performed in 16 cadaveric specimens. PICA caliber and number of perforators were measured at p1 and p3 segments. OA-p3 PICA end-to-side and OA-p1 PICA end-to-end bypasses were compared.

RESULTS

OA-p1 PICA bypass with end-to-end anastomosis was performed in 16 specimens; whereas, OA-p3 PICA bypass with end-to-side anastomosis was performed in 11. Mean distance from OA at the occipital groove to the anastomosis site was shorter for p1 than p3 segments (30.2 vs 48.5 mm; P < .001). Median number of perforators on p1 was 1, and on p3, it was 4 (P < .001).

CONCLUSION

Although most OA-PICA bypasses can be performed using the p3 segment as the recipient site for an end-to-side anastomosis, a more feasible alternative to conventional OA-p3 PICA bypass in cases of high-riding caudal loops or aberrant anatomy is to free the p1 PICA, transpose it away from the lower cranial nerves, and perform an end-to-end OA-p1 PICA bypass instead.

Retromastoid-transmuscular identification and harvest of the occipital artery during retrosigmoid craniotomy

OBJECTIVE

Harvesting the occipital artery (OA) is challenging. The subcutaneous OA is usually found near the superior nuchal line and followed proximally, requiring a large incision and risking damage to the superficially located OA. The authors assessed the anatomical feasibility and safety of exposing the OA through a retromastoid-transmuscular approach.

METHODS

Using 10 cadaveric heads, 20 OAs were harvested though a 5-cm retroauricular incision placed 5 cm posterior to the external auditory meatus. The underlying muscle layers were sequentially cut and recorded before exposing the OA. Changes in the orientation of muscle fibers were used as a roadmap to expose the OA without damaging it.

RESULTS

The suboccipital segment of the OA was exposed without damage after incising two consecutive layers of muscles and their investing fasciae. These muscles displayed different fiber directions: the superficially located sternocleidomastoid muscle with vertically oriented fibers, and the underlying splenius capitis with anteroposteriorly (and mediolaterally) oriented fibers. The OA could be harvested along the entire length of the skin incision in all specimens. If needed, the incision can be extended proximally and/or distally to follow the OA and harvest greater lengths.

CONCLUSIONS

This transmuscular technique for identification of the OA is a reliable method and may facilitate exposure and protection of the OA during a retrosigmoid approach. This technique may obviate the need for larger incisions when planning a bypass to nearby arteries in the posterior circulation via a retrosigmoid craniotomy. Additionally, the small skin incision can be enlarged when a different craniotomy and/or bypass is planned or when a greater length of the OA is needed to be harvested.

Occipital artery to p3 segment of posterior inferior cerebellar artery bypass in treating a complex fusiform aneurysm

We provide a case report of a 58-year-old man who presented with a ruptured fusiform dissecting aneurysm located at the junction of the vertebral artery and posterior inferior cerebellar artery (PICA). Due to the lesion's complexity, a two-step approach was planned for revascularisation of PICA using the occipital artery (OA) prior to coiling embolisation. An end-to-side OA-PICA bypass was performed with implantation at the caudal loop of the p3 PICA segment. Fifteen days after the procedure, the aneurysm underwent stent-assisted coiling for successful obliteration of the aneurysm. The patient tolerated this procedure well and now at 1.5 years of follow-up remains free from any neurological deficits (modified Rankin Score 0). This case report illustrates one of the unique scenarios where both the vascular territory involved and morphological features of the aneurysm prohibited the use of more conventional means, necessitating the use of an arterial bypass graft for successful treatment of this lesion. As open vascular surgery is becoming less common in the age of endovascular coiling, our article uniquely reports on the combined use of both endovascular and microsurgical techniques to treat a complex aneurysm of the posterior circulation.

Anterior Inferior Cerebellar Artery Bypasses: The 7-Bypass Framework Applied to Ischemia and Aneurysms in the Cerebellopontine Angle

BACKGROUND

Aneurysms of the anterior inferior cerebellar artery (AICA) are rare. Primary clip reconstruction of these lesions is a challenge because of the limited surgical exposure and frequent nonsaccular aneurysm morphology. Endovascular treatment options exist, but outcomes are equivalent to those for open surgery. Historically, AICA aneurysms not amenable to clipping or primary coiling have been treated with parent vessel sacrifice.

OBJECTIVE

To determine whether an AICA revascularization strategy would afford for the safe treatment of AICA aneurysms and other posterior circulation pathologies without compromising perfusion of the AICA territories.

METHODS

We describe a series of AICA bypasses to treat 4 AICA aneurysms and 3 vertebral artery/AICA occlusions.

RESULTS

We used 7 types of bypasses to revascularize the AICA territory. Bypass types included extracranial-to-intracranial (EC-IC) bypass without an interpositional graft, EC-IC with an interpositional graft, in situ bypass, reanastomosis, reimplantation, intracranial-to-intracranial bypass with interpositional graft, and combination bypasses. In particular, we performed the following 7 bypasses: OA-a3 AICA, OA-RAG-a3 AICA, p3 PICA-a3 AICA, a2 AICA reanastomosis, V4 VA-a3 AICA, V3 VA-SVG-a3 AICA, and a combined OA-a3 AICA bypass and p3 PICA reanastomosis. AICA revascularization allows for the safe treatment of AICA aneurysms and other posterior circulation pathologies without compromising perfusion of the AICA territories.

CONCLUSION

All 7 AICA bypasses are feasible for application to AICA aneurysms and ischemic disease. Our experience with the 7-bypass framework demonstrates the utility of the framework as a decision-making tool and the breadth of bypass innovation possible in this anatomically challenging region.

A Classification for the Anterior Inferior Cerebellar Artery-Subarcuate Artery Complex Based on the Embryological Development

Objective  To hierarchize the anterior inferior cerebellar artery (AICA)-subarcuate artery (SAA) complex's variations in the surgical field. Background  The AICA's "subarcuate loop" (SL) presents multiple variations, closely related to the SAA. AICA-SAA complex's variations may represent major issues in cerebellopontine angle (CPA) surgery. As the spectrum of configurations is originated during the development, a systematized classification was proposed based on the interaction between the petrosal bone and the AICA in the embryonic period. Methods  The variations were defined as follow: Grade 0: free, purely cisternal AICA, unidentifiable or absent SAA; Grade 1: purely cisternal AICA, loose SL, SAA > 3 mm; Grade 2: AICA near the subarcuate fossa, pronounced SL, SAA <3 mm; Grade 3: "duralized" AICA, unidentifiable SAA, or included in the petromastoid canal (PMC); and Grade 4: intraosseous AICA, unidentifiable SAA, or included in the PMC. The classification was applied to a series of patients assessed by magnetic resonance constructive interference in steady state sequence. Surgical examples were also provided. Results  Eighty-four patients were evaluated, including 161 CPA. The proportions found in the gradation remained within the range of previous publications (Grade 0: 42.2%; Grade 1: 11.2%; Grade 2: 35.4%; Grade 3: 10.6%; and Grade 4: 0.6%). Moreover, the degrees of the classification were related to the complexity of the anatomical relationships and, therefore, to the difficulty of the maneuvers required to overcome them. Conclusion  The proposed AICA-SAA complex classification allowed to distinguish and objectify pre- and intraoperatively the spectrum of variations, to thoroughly plan the required actions and instrumentation.

Clinical importance of the occipital artery in vascular lesions: A review of the literature

The occipital artery (OA) is a critical artery in vascular lesions. However, a comprehensive review of the importance of the OA is currently lacking. In this study, we used the PubMed database to perform a review of the literature on the OA to increase our understanding of its role in vascular lesions. We also provided our typical cases to illustrate the importance of the OA. The OA has several variations. For example, it may arise from the internal carotid artery or anastomose with the vertebral artery. Therefore, the OA may provide a crucial collateral vascular supply source and should be preserved in these cases. The OA is a good donor artery. Consequently, it is used in extra- to intracranial bypasses for moyamoya disease (MMD) or aneurysms. The OA can be involved in dural arteriovenous fistula (DAVF) and is a feasible artery for the embolisation of DAVF. True aneurysms and pseudoaneurysms can occur in the OA; surgical resection and embolisation are the effective treatment approaches. Direct high-flow AVF can occur in the OA; embolisation treatment is a good option in such cases. The OA can also be involved in MMD and brain arteriovenous malformation (AVM) by forming transdural collaterals. For a patient in the prone position, if occipital and suboccipital craniotomies are performed, the OA can also be used for intraoperative angiography. In brief, the OA is a very important artery in vascular lesions.

Treatment of an Anterior Inferior Cerebellar Artery Aneurysm With Microsurgical Trapping and In Situ Posterior Inferior Cerebellar Artery to Anterior Inferior Cerebellar Artery Bypass: Case Report

BACKGROUND

Anterior inferior cerebellar artery (AICA) aneurysms are rare lesions whose treatment can involve microsurgical and/or endovascular techniques. Such treatment can be challenging and may carry a significant risk of neurological morbidity.

OBJECTIVE

To demonstrate a case involving a complex AICA aneurysm that was treated with a unique microsurgical approach involving trapping the aneurysm and performing in Situ bypass from the posterior inferior cerebellar artery (PICA) to the distal AICA. The nuances of AICA aneurysms and revascularization strategies are discussed.

METHODS

The aneurysm and the distal segments of AICA and PICA were exposed with a retrosigmoid and far lateral approach. A side-to-side anastomosis was performed between the adjacent caudal loops of PICA and AICA. The AICA aneurysm was then treated by trapping the aneurysm-bearing segment of the parent vessel between 2 clips.

RESULTS

A postoperative angiogram demonstrated a patent PICA-AICA bypass and complete occlusion of the AICA aneurysm. There were no complications, and the patient made an excellent recovery.

CONCLUSION

The combination of parent vessel sacrifice and bypass remains an excellent option for certain difficult-to-treat aneurysms. This case involving PICA-AICA bypass to treat an AICA aneurysm serves as an example of the neurosurgeon's ability to develop unique solutions that take advantage of individual anatomy.

Anterior inferior cerebellar artery aneurysms: Segments and results of surgical and endovascular managements

BACKGROUND

Anterior inferior cerebellar artery (AICA) aneurysms are rare and published clinical experience with these aneurysms is limited.

OBJECTIVE

The objective of this article is to report angiographic characteristics and results associated with premeatal, meatal and postmeatal segments, surgical and endovascular therapies.

METHODS

A literature review was performed through PubMed using "anterior inferior cerebellar artery aneurysm" through January 2016. Clinical data, angiograms, management techniques, and patient outcomes were reviewed for 47 collected cases in 30 previous reports.

RESULTS

Of these aneurysms, 21 (44.7%) were associated with meatal segment, 10 (21.3%) were postmeatal and 16 (34.0%) were premeatal. Patients with meatal aneurysms are more likely to present with subarachnoid hemorrhage and hearing loss and facial palsy (77.8%). Patient outcomes of meatal aneurysms presented with more neuropathies (51.7%) and cerebellar symptoms (14.3%) (p = 0.049). Four cases of meatal aneurysm with preoperative cranial nerve deficits (two VII and two VIII) showed improvement after surgery. Endovascular treatment achieved outcomes similar to surgical treatment (p = 0.327).

CONCLUSIONS

AICA aneurysms have a predilection for meatal segment. Patients with meatal aneurysms are more likely to present with subarachnoid hemorrhage and hearing loss and facial palsy. Patient outcomes of meatal aneurysms presented with more neuropathies and cerebellar symptoms. Endovascular treatment achieved outcomes similar to surgical treatment.

Ruptured Total Intrameatal Anterior Inferior Cerebellar Artery Aneurysm

Among the distal anterior inferior cerebellar artery (AICA) aneurysms, a unique aneurysm at the meatal loop inside the internal auditory meatus is extremely rare. The authors report a case of surgically treated total intrameatal AICA aneurysm. A 62-year-old female patient presenting with sudden bursting headache and neck pain was transferred to our department. Computed tomography and digital subtraction angiography showed subarachnoid hemorrhage at the basal, prepontine cistern and an aneurysm of the distal anterior inferior cerebellar artery inside the internal auditory meatus. Surgery was performed by retrosigmoid craniotomy with unroofing of the internal auditory meatus. The aneurysm was identified between the seventh and eighth cranial nerve in the meatus and was removed from the canal and clipped with a small straight Sugita clip. After operation the patient experienced transient facial paresis and tinnitus but improved during follow up.

Ruptured distal AICA pseudoaneurysm presenting years after vestibular schwannoma resection and radiation

Distal anterior inferior cerebellar artery (AICA) pseudoaneurysms are very rare lesions. Although cases have been previously reported, only a few have been reported as a result of vestibular schwannoma (VS) radiation, none have been reported as a result of VS resection, and only one has been reported as treated with parent vessel occlusion (PVO) with n-butyl cyanoacrylate (nBCA). We report a case of a 65-year-old man with a history of right-sided VS surgery and radiation who presented years later with a ruptured pseudoaneurysm of the distal right AICA and was treated with endovascular PVO using nBCA. The aneurysm was completely obliterated and the patient had no worsening of symptoms or neurological exam. The case illustrates a very rare complication of VS surgery and radiation as well as an effective treatment for distal AICA aneurysms.

Ruptured distal AICA pseudoaneurysm presenting years after vestibular schwannoma resection and radiation

Distal anterior inferior cerebellar artery (AICA) pseudoaneurysms are very rare lesions. Although cases have been previously reported, only a few have been reported as a result of vestibular schwannoma (VS) radiation, none have been reported as a result of VS resection, and only one has been reported as treated with parent vessel occlusion (PVO) with n-butyl cyanoacrylate (nBCA). We report a case of a 65-year-old man with a history of right-sided VS surgery and radiation who presented years later with a ruptured pseudoaneurysm of the distal right AICA and was treated with endovascular PVO using nBCA. The aneurysm was completely obliterated and the patient had no worsening of symptoms or neurological exam. The case illustrates a very rare complication of VS surgery and radiation as well as an effective treatment for distal AICA aneurysms.

Genetics and Biomarkers of Moyamoya Disease: Significance of RNF213 as a Susceptibility Gene

Moyamoya disease is characterized by a progressive stenosis at the terminal portion of the internal carotid artery and an abnormal vascular network at the base of the brain. Although its etiology is still unknown, recent genome-wide and locus-specific association studies identified RNF213 as an important susceptibility gene of moyamoya disease among East Asian population. A polymorphism in c.14576G>A in RNF213 was identified in 95% of familial patients with moyamoya disease and 79% of sporadic cases, and patients having this polymorphism were found to have significantly earlier disease onset and a more severe form of moyamoya disease, such as the presentation of cerebral infarction and posterior cerebral artery stenosis. The exact mechanism by which the RNF213 abnormality relates to moyamoya disease remains unknown, while recent reports using genetically engineered mice lacking RNF213 by homologous recombination provide new insight for the pathogenesis of this rare entity. Regarding biomarkers of moyamoya disease, moyamoya disease is characterized by an increased expression of angiogenic factors and pro-inflammatory molecules such as vascular endothelial growth factors and matrix metalloproteinase-9, which may partly explain its clinical manifestations of the pathologic angiogenesis, spontaneous hemorrhage, and higher incidence of cerebral hyperperfusion after revascularization surgery. More recently, blockade of these pro-inflammatory molecules during perioperative period is attempted to reduce the potential risk of surgical complication including cerebral hyperperfusion syndrome. In this review article, we focus on the genetics and biomarkers of moyamoya disease, and sought to discuss their clinical implication.