Therapeutic effect of multiple burr hole operation combined with dural inversion and periosteal synangiosis for moyamoya disease

Revascularisation patterns and characteristics after erythropoietin pretreatment and multiple burr holes in patients who had acute stroke with perfusion impairment

BACKGROUND

Transdural collaterals, originating mainly from the extracalvarial superficial temporal artery and intracalvarial middle meningeal artery via the external carotid artery (ECA), have been observed after revascularisation surgery. However, the origin of these collaterals in patients with stroke with perfusion insufficiency is not yet known. Therefore, we studied the revascularisation patterns and characteristics based on the origin of these collaterals.

METHODS

We employed erythropoietin pretreatment and performed multiple burr holes under local anaesthesia to achieve transdural revascularisation in patients with acute stroke with perfusion insufficiency. After 6 months, we reassessed the transfemoral cerebral angiography to evaluate the revascularisation patterns. The collaterals were categorised into intracalvarial ECA-dominant (originating from the middle meningeal artery), extracalvarial ECA-dominant (originating from the superficial temporal or occipital artery) and balanced groups. We compared various imaging parameters among these groups.

RESULTS

Overall, 87 patients with 103 treated hemispheres were involved. Among them, 57.3% were classified as intracalvarial ECA-dominant, 20.4% as extracalvarial ECA-dominant and 22.3% as balanced. Most of the hemispheres with intracalvarial or extracalvarial collaterals (vs balanced collaterals) showed successful revascularisation (78/80 (97.5%) vs 12/23 (52.1%)), p<0.001). In ultrasonographic haemodynamic changes according to revascularisation pattern, only the intracalvarial ECA-dominant revascularisation was significantly associated with specific changes in ECA blood flow, leading to the conversion to a low-resistance ECA Doppler sonography waveform.

CONCLUSIONS

Our findings suggest that intracalvarial ECA-dominant revascularisation plays a crucial role in the formation of transdural collaterals following combined therapy. These distinct changes in ECA haemodynamics can be non-invasively identified through bedside ultrasound studies.

ASL-MRI-guided evaluation of multiple burr hole revascularization surgery in Moyamoya disease

PURPOSE

Moyamoya (MM) disease is characterized by progressive intracranial arterial stenosis. Patients commonly need revascularization surgery to optimize cerebral blood flow (CBF). Estimation of CBF and cerebrovascular reserve (CVR) is therefore necessary before and after surgery. However, assessment of CBF before and after indirect revascularization surgery with the multiple burr hole (MBH) technique in MM has not been studied extensively. In this study, we describe our initial experience using arterial spin labeling magnetic resonance perfusion imaging (ASL-MRI) for CBF and CVR assessment before and after indirect MBH revascularization surgery in MM patients.

METHODS

Eleven MM patients (initial age 6-50 years, 1 male/10 female) with 19 affected hemispheres were included. A total of 35 ASL-MRI examinations were performed using a 3D-pCASL acquisition before and after i.v. acetazolamide challenge (1000 mg in adults and 10 mg/kg in children). Twelve MBH procedures were performed in seven patients. The first follow-up ASL-MRI was performed 7-21 (mean 12) months after surgery.

RESULTS

Before surgery, CBF was 46 ± 16 (mean ± SD) ml/100 g/min and CVR after acetazolamide challenge was 38.5 ± 9.9 (mean ± SD)% in the most affected territory (middle cerebral artery). In cases in which surgery was not performed, CVR was 56 ± 12 (mean ± SD)% in affected hemispheres. After MBH surgery, there was a relative change in CVR compared to baseline (preop) of + 23.5 ± 23.3% (mean ± SD). There were no new ischemic events.

CONCLUSION

Using ASL-MRI we followed changes in CBF and CVR in patients with MM. The technique was encouraging for assessments before and after revascularization surgery.

Outcomes after superficial temporal artery–middle cerebral artery anastomosis combined with multiple burr hole surgery and dural inversion synangiosis for moyamoya disease in adults

Objective

Several forms of cerebral revascularization have been carried out to treat moyamoya disease, however, the existing methods are accompanied by a variety of complications. In this study, the authors aimed to evaluate the clinical and angiographic outcomes of a new surgical procedure: superficial temporal artery–middle cerebral artery (STA-MCA) anastomosis combined with multiple burr hole (MBH) surgery and dural inversion synangiosis for the treatment of moyamoya disease in adults.

Methods

Patients treated for moyamoya disease from August 2019 to July 2021 were retrospectively reviewed. Clinical data, including perioperative complications and follow-up outcomes, were noted. Preoperative and postoperative angiograms were compared, and the diameters of the frontal branch of the superficial temporal artery (F-STA), the deep temporal artery (DTA), the distal superficial temporal artery (STA) before the bifurcation and the middle meningeal artery (MMA) were measured on preoperative and postoperative angiograms. Meanwhile, a Matsushima score was assigned from postoperative angiograms.

Results

This study included 66 patients (67 hemispheres). During the follow-up period, a median of 18 (IQR, 13–21) months, no stroke or death occurred in any of the patients. The clinical outcomes were excellent in 27 patients (40.9%), good in 34 patients (51.6%), fair in 4 patients (6.0%), and poor in 1 patient (1.5%); the overall rate of favorable clinical outcomes (excellent and good) was 92.5%. The modified Rankin Scale (mRS) score was significantly improved at follow-up (P < 0.001). There were 41 hemispheres imaged by cerebral angiography after the operation, at a median postoperative interval of 9 (IQR, 8–12) months; among them, 34 (82.9%) hemispheres had Matsushima scores of grade A and grade B. The average postoperative diameters in the STA, DTA and MMA were increased significantly in 41 hemispheres at follow-up (P < 0.001). Sixteen (24.2%) patients suffered from perioperative complications, including focal hyperperfusion syndrome (HS) in 8 (12.2%) patients, cerebral infarction in 3 (4.5%) patients (including one case accompanied by wound infection), cerebral hemorrhage in 2 (3.0%) patients, seizures in 2 (3.0%) patients, and subdural effusion in 1 (1.5%) patient.

Conclusions

The procedure of STA-MCA anastomosis combined with MBH surgery and dural inversion synangiosis may be a safe and effective treatment for adult patients with moyamoya disease.

Surgical techniques and indications for treatment of adult moyamoya disease

Moyamoya disease (MMD) is a chronic, progressive cerebrovascular disease involving the occlusion or stenosis of the terminal portion of the internal carotid artery (ICA) and the proximal anterior and middle cerebral arteries. Adults with MMD have been shown to progressively accumulate neurological and cognitive deficits without treatment, with a mortality rate double that of pediatric patients with MMD. Surgical intervention is the mainstay of treatment to prevent disease progression and improve clinical outcomes. Several different types of bypasses can be utilized for revascularization in MMD, including indirect, direct, and combined forms of extracranial-to-intracranial (EC-IC) bypass. Overall, the choice of appropriate technique requires consideration of the age of the patient, preoperative hemodynamics, neurologic status, and territories most at risk and in need of revascularization. Here, we will review the indications and surgical techniques for the treatment of adult MMD. Step-by-step instructions for performing several bypass variants with technical pearls are discussed.

Salvage multiple burr hole surgery in patients with Moyamoya disease: efficacy evaluation using probabilistic independent component analysis of dynamic susceptibility contrast perfusion MRI

PURPOSE

Multiple burr hole surgery is considered to be an option for achieving indirect revascularization in patients with ischemic Moyamoya disease (MMD). We aimed to investigate the efficacy of stand-alone multiple burr hole surgery for salvage revascularization in patients with MMD by assessing the hemodynamic changes via normalized time-to-peak (nTTP) analysis and independent component analysis (ICA) of preoperative and postoperative dynamic susceptibility contrast (DSC) perfusion MRI data.

METHODS

The DSC perfusion MRI data of 25 hemispheres from 21 patients with MMD, who underwent multiple burr hole surgery for salvage revascularization due to persistent or recurrent symptoms after primary revascularization with modified encephaloduroarteriosynangiosis (mEDAS), were analyzed. The nTTP, which was measured using the region of interests covering the entire surgical hemisphere, was compared between the preoperative and postoperative images. ICA was used to compare the relative arterial and venous components of the surgical hemispheres between the respective preoperative and postoperative images.

RESULTS

The median postoperative nTTP (1.80 s) was significantly shorter than the median preoperative nTTP (4.10 s) (P < 0.001). The postoperative relative arterial component of the surgical hemisphere (median: 0.04) was significantly higher than the preoperative relative arterial component (median: - 0.02, P < 0.001). In contrast, the postoperative relative venous component of the surgical hemisphere (median: - 0.05) was significantly lower than the preoperative value (median: 0.05, P < 0.001).

CONCLUSION

The improvement in cerebral perfusion parameters observed on postoperative DSC perfusion MRI demonstrated that stand-alone multiple burr hole surgery could be a favorable salvage revascularization technique after mEDAS failure in patients with ischemic MMD.

Clinical Features and Treatment Outcomes of Cerebral Arteriovenous Malformation Associated With Moyamoya Disease

BACKGROUND

Cerebral arteriovenous malformation (AVM) can rarely occur in conjunction with moyamoya disease (MMD). There is still no consensus on how to treat AVM when accompanied by MMD. In this study, we assessed the clinical features and suggested appropriate management when AVM was combined with MMD.

METHODS

From August 1994 to December 2020, 7 out of 4004 patients with MMD were found to have AVM. The Karnofsky Performance Scale (KPS) was used to evaluate the clinical outcomes of AVM and MMD. KPS greater than 80 was classified as a good outcome. In addition, the radiologic outcomes of the patients were evaluated.

RESULTS

The incidence of AVM with MMD was 1.7 per 1000 persons. Five patients underwent bypass surgery for MMD, and 5 patients underwent Gamma Knife surgery (GKS) for concurrent AVM. Postoperative perfusion magnetic resonance imaging and brain single photon emission computerized tomography showed improved cerebral hemodynamics in 4 out of 7 territories. Postoperative cerebral angiography showed good revascularization in 4 out of 8 territories. After GKS, 4 patients showed complete obliteration, and 1 patient showed a significantly decreased AVM size. Six patients showed favorable clinical outcomes (KPS 80-100), and 1 patient with delayed GKS for AVM had a poor outcome (KPS 20) due to AVM rupture.

CONCLUSIONS

In this study, AVM tended to occur where the angiographic stage of MMD was higher. When AVM is combined with MMD, MMD bypass surgery is recommended based on symptoms and cerebral perfusion status. For AVM, less invasive but effective treatments, such as GKS, should be implemented as soon as possible.

Limits and pitfalls of indirect revascularization in moyamoya disease and syndrome

Moyamoya vasculopathy is a rare chronic cerebrovascular disorder characterized by the stenosis of the terminal branches of the internal carotid arteries and the proximal tracts of anterior and middle cerebral arteries. Although surgical revascularization does not significantly change the underlying pathogenic mechanisms, it plays a pivotal role in the management of affected individuals, allowing to decrease the risk of ischemic and hemorrhagic complications. Surgical approaches may be direct (extracranial-intracranial bypass), indirect, or a combination of the two. Several indirect techniques classifiable according to the tissue (muscle, periosteum, galea, dura mater, and extracranial tissues) or vessel (artery) used as a source of blood supply are currently available. In this study, we reviewed the pertinent literature and analyzed the advantages, disadvantages, and pitfalls of the most relevant indirect revascularization techniques. We discussed the technical aspects and the therapeutical implications of each procedure, providing a current state-of-the-art overview on the limits and pitfalls of indirect revascularization in the treatment of moyamoya vasculopathy.

Treatment strategies of ruptured intracranial aneurysms associated with moyamoya disease

OBJECTIVE

The purpose of this study was to present our experience in the management of ruptured intracranial aneurysms associated with moyamoya disease (MMD), and to discuss their treatment strategies and the timing of revascularization surgery.

PATIENTS AND METHODS

Thirteen patients who had ruptured intracranial aneurysms associated with MMD were enrolled in this study. Different treatment strategies were adopted based on the location of the aneurysms. Their clinical and radiologic features, treatment selection and outcomes were retrospectively reviewed.

RESULTS

Among the five patients with major artery aneurysms in anterior circulation, three were embolized and two clipped. Among the five patients with major artery aneurysms in posterior circulation, three were treated by endovascular coiling. Among the three peripheral aneurysms, one was treated by endovascular embolization, one by aneurysmectomy, and the other one by revascularization alone. For the patients whose aneurysms were treated by endovascular embolization or surgery, a staged revascularization was performed on day 28 to day 87 after the first operation. For the two patients with aneurysms untreated directly, the timing of revascularization was 20 days and 54 days after hemorrhage, respectively. During the follow-up recurrent intracranial hemorrhage occurred in a patient, but not caused by the previous aneurysm. No other patients suffered recurrent intracranial hemorrhage or ischemic stroke. Complete occlusion was achieved in all the 11 aneurysms that had been clipped or embolized. Of the remaining three aneurysms that had not been directly treated, one disappeared spontaneously, whereas the other two remained stable. The direct and indirect bypasses were confirmed patent in the 11 patients who had undergone revascularization.

CONCLUSION

Our current treatment strategies and timing of revascularization may provide a benefit for the patients with MMD accompanied by ruptured intracranial aneurysms.

Preservation of the Arachnoid Membrane During Encephaloduroarteriosynangiosis Reduces Postoperative Complications without Undermining the Surgical Outcome in Pediatric Moyamoya Disease

BACKGROUND

Encephaloduroarteriosynangiosis (EDAS) is a commonly used indirect revascularization operation method to treat pediatric patients with Moyamoya disease (MMD). Arachnoid dissection frequently has been performed during the EDAS operation to promote better revascularization. However, no studies have yet proven its surgical benefits. In this study, we investigated the impact of arachnoid preservation on the surgical outcome and postoperative complication by comparing pediatric patients with MMD who had the arachnoid membrane preserved during EDAS operation with those who had it dissected.

METHODS

This was a retrospective cohort study based on a single surgeon's experience at a single institution. A total of 206 pediatric patients with MMD who underwent EDAS operation at Seoul National University Children's Hospital were recruited for the study. We compared the surgical outcome and the postoperation complication rate of these 2 groups. Furthermore, risk factors for postoperative complication were analyzed.

RESULTS

The overall clinical outcome (P = 0.342) and the extent of revascularization of middle cerebral artery territories (P = 0.736) were not different between the arachnoid dissection group and the arachnoid preservation group. However, the postoperative infarction/hemorrhage rate was significantly greater in the arachnoid dissection group (P = 0.005). Arachnoid dissection (P = 0.011) and young age (<3 years old, P = 0.012) were significantly associated with increased risk of postoperative complications.

CONCLUSIONS

Arachnoid preservation may help to reduce postoperative complications without decreasing the surgical outcome of EDAS. Furthermore, factors such as the patient's age should be taken into account when treating pediatric patients with MMD.

Results of more than 20 years of follow-up in pediatric patients with moyamoya disease undergoing pial synangiosis

OBJECTIVE

There are limited data on the long-term outcomes for children undergoing surgical revascularization for moyamoya disease (MMD) in North America. The authors present a series of pediatric MMD patients who underwent a standard revascularization procedure, pial synangiosis, more than 20 years previously at a single institution by a single surgical team.

METHODS

This study is a retrospective review of all patients aged 21 years or younger treated for MMD at Boston Children's Hospital who were operated on more than 20 years previously by the senior author (R.M.S.). Radiographic and operative reports, outpatient clinical records, and communications with patients and families were reviewed to document current clinical status, ability to perform daily activities, and concurrent or new medical conditions.

RESULTS

A total of 59 patients (38 female [64.4%], 21 male [35.6%]; median age at surgery 6.2 years [IQR 0.5-21 years]) were identified who were diagnosed with MMD and underwent surgical revascularization procedures more than 20 years previously. Clinically, all but 2 patients (96.6%) presented with the following symptoms alone or in combination: 43 (73%) presented with stroke, 22 (37%) with transient ischemic attack, 12 (20%) with seizures, 7 (12%) with headache, 3 (5%) with choreiform movements, and 2 (3%) with hemorrhage; MMD was incidentally detected in 2 patients (3%). Five patients had unilateral MMD at presentation, but 3 of these ultimately progressed to develop bilateral MMD after an average of 16 months; therefore, pial synangiosis was ultimately performed in a total of 116 hemispheres during the study period. Clinical follow-up was available at a median interval of 20.6 years (IQR 16.1-23.2 years). Modified Rankin Scale scores were stable or improved in 43 of 50 patients with evaluable data; 45 of 55 are currently independent. There were 6 patient deaths (10.2%; 3 due to intracranial hemorrhage, 2 due to tumor-related complications, and 1 due to pulmonary artery stenosis), 4 of whom had a history of previous cranial radiation. One patient (1.7%) experienced a late stroke. Synangiosis vessels remained patent on all available late MRI and MRA studies. Four patients reported uneventful pregnancies and vaginal deliveries years following their revascularization procedures.

CONCLUSIONS

Revascularization for MMD by pial synangiosis appears to confer protection from stroke for pediatric patients over long-term follow-up. A history of cranial radiation was present in 4 of the 6 patients who died and in the lone patient with late stroke. Most patients can expect productive, independent lives following revascularization surgery in the absence of significant preoperative neurological deficits and comorbidities.

Multiple Burr-Hole Surgery for the Treatment of Moyamoya Disease and Quasi-Moyamoya Disease in Children: Preliminary Surgical and Imaging Results

OBJECTIVE

Moyamoya disease (MMD) is characterized by a progressive spontaneous occlusion of distal internal carotid arteries and its main branches. It is necessary to promptly diagnose and treat this condition, especially in children, because of the high risk of stroke and consequent severe disability. In this study, we examine the role of multiple burr-hole surgery (MBHS) in the treatment of pediatric patients with MMD and quasi-MMD and the role of perfusion magnetic resonance imaging (MRI) in the surgical indication and during follow-up.

METHODS

We reviewed preoperative, early postoperative, and late postoperative MRI perfusion and digital subtraction angiography images together with clinical and surgical outcomes in 10 children with MMD treated by MBHS.

RESULTS

Fourteen MBHS procedures (6 unilateral, 2 bilateral, and 2 single-setting bilateral) were performed in 10 children. Clinical and radiologic follow-up for all patients ranges from 16 months to 7 years. No ischemic events (transient ischemic attacks or stroke) occurred during the follow-up period. Postoperative digital subtraction angiography showed good revascularization around the burr-hole sites in all patients. The functional efficacy of the surgery was confirmed by dynamic susceptibility contrast perfusion MRI studies in 8 patients.

CONCLUSIONS

Our data underline the good rate of success of MBHS in pediatric MMD and quasi-MMD. This technique results in good collateral revascularization, improved cerebral perfusion and excellent short and long-term symptoms control, with low perioperative risk. Postoperative changes of perfusion parameters and ivy sign MRI finding seem to show a positive correlation and mainly occur in posterior middle cerebral artery territory.

How I do it: operative nuances of multiple burr hole surgery for moyamoya disease and syndrome

BACKGROUND

Burr hole surgery for moyamoya disease and moyamoya syndrome is known to be an effective, versatile, and relatively simple revascularization technique. We will focus on the technical operative aspects of multiple burr hole surgery as we perform it in our center.

METHODS

Periosteal flaps are prepared and placed in a burr hole with beveled edge, after opening the dura and arachnoid membrane, in order to facilitate neovascularization into the ischemic cortex.

CONCLUSIONS

Burr hole surgery is a versatile treatment modality for moyamoya and moyamoya-like disease. Success can be maximized by having a meticulous operative technique.

Indirect revascularization with the dural inversion technique for pediatric moyamoya disease: 20-year experience

OBJECTIVENumerous surgical procedures facilitate revascularization of the ischemic brain in patients with moyamoya disease. Dural inversion is a technique in which flaps of dura mater centered around the middle meningeal artery are inverted, encouraging the formation of a rich collateral blood supply. This procedure has been used in combination with encephaloduroarteriosynangiosis for more than 20 years at the authors' institution for the treatment of pediatric moyamoya disease. The objective of this study was to describe the clinical and radiographic outcomes for a cohort of consecutive pediatric moyamoya patients undergoing dural inversion.METHODSClinical and radiographic data on patients who had undergone dural inversion in the period from 1997 to 2016 were reviewed. Univariate and multivariate logistic regression and Kaplan-Meier analyses were performed to assess the risk of postoperative stroke, functional outcome, and the angiographic degree of revascularization.RESULTSDural inversion was performed on 169 hemispheres in 102 patients. Median follow-up was 4.3 years. Six patients (3.6% of hemispheres) suffered postoperative ischemic or hemorrhagic stroke. Overall mortality was 1.0%. Good postoperative neurological status (modified Rankin Scale [mRS] score ≤ 2) was observed in 90 patients (88%); preoperative and postoperative mRS scores showed significant improvement (p < 0.001). Eighty-six percent of hemispheres had Matsushima grade A or B revascularization. Younger age was associated with postoperative stroke and poor functional outcome. Patients with secondary moyamoya syndrome had a significantly worse radiographic outcome. The cumulative 5-year Kaplan-Meier risk for stroke was 6.4%.CONCLUSIONSDural inversion is a useful technique of cerebral revascularization in pediatric moyamoya disease. A 20-year experience demonstrates the safety and efficacy of this technique with a relatively low rate of postoperative stroke, good functional outcomes, and favorable angiographic results.

Improving Indirect Revascularization for Effective Treatment of Adult Moyamoya Disease: A Prospective Clinical, Cerebral Angiographic, and Perfusion Study

BACKGROUND

Indirect revascularization is simple and safe, but it is not commonly used in adult moyamoya disease owing to its unreliable effect. This prospective study aimed to evaluate the effectiveness of indirect revascularization in treating adult moyamoya disease after refinement of the surgical technique and perioperative care.

METHODS

Adult patients who underwent indirect revascularization as the primary treatment for moyamoya disease between November 2013 and January 2017 were studied. The indirect revascularization procedures included encephalo-duro-arterio-synangiosis and encephalo-myo-synangiosis in the temporal region and encephalo-pericranio-synangiosis in other hypoperfusion areas. The preoperative and postoperative clinical conditions, cerebral angiography findings, and time-to-peak prolongation areas on magnetic resonance perfusion studies were assessed to evaluate the revascularization effect. Refinements of the surgical technique included the selection of surgical area based on perfusion imaging, craniotomy size, and number of affected hemispheres, along with the inclusion of a dural flap in every procedure.

RESULTS

Nineteen patients (17 females and 2 males), and a total of 31 cerebral hemispheres, were included. The mean patient age was 32.7 ± 11.4 years. After a mean follow-up of 38.6 ± 11.5 months, all patients showed clinical improvement or stabilization. Available postoperative angiography demonstrated Matsushima grade A or B in 19 of 21 hemispheres. The mean time-to-peak prolongation index of all 31 hemispheres improved from 24.09 ± 9.83% preoperatively to 12.82 ± 6.75% at 3-6 months after surgery (P < 0.001). The complication rate was 12.9%, and all complications were transient.

CONCLUSIONS

With refinements of surgical techniques and perioperative care, indirect revascularization is more reliable and can be a viable alternative treatment for adult moyamoya disease. In our cohort, outcomes were satisfactory, with mean 38.6-month follow-up.

Moyamoya Disease: Treatment and Outcomes

Although the pathogenesis of moyamoya disease (MMD) has not been fully elucidated, the effectiveness of surgical revascularization in preventing stroke has been addressed by many studies. The main mechanism of surgical revascularization is augmenting the intracranial blood flow using an external carotid system by either direct bypass or pial synangiosis. This can improve resting cerebral blood flow as well as vascular reserve capacity. For direct revascularization, the superficial temporal artery is used as the donor artery in most cases, although the occipital artery may be used in limited cases. Usually, the cortical branch of the middle cerebral artery is selected as the recipient of direct anastomosis. As for indirect revascularization, various techniques using different kinds of connective tissues have been introduced. In some cases, reinforcing the anterior cerebral artery and the posterior cerebral artery territories can be considered. The effectiveness of surgical revascularization for preventing ischemic stroke had been generally accepted by many studies. However, for preventing hemorrhagic stroke, new evidence has been added by a recent randomized controlled trial. The incidence of peri-operative complications such as stroke and hyperperfusion syndrome seems to be high due to the nature of the disease and technical demands for treatment. Preventing and adequately managing these complications are essential for ensuring the benefits of surgery.

Clinical importance of the middle meningeal artery: A review of the literature

The middle meningeal artery (MMA) is a very important artery in neurosurgery. Many diseases, including dural arteriovenous fistula (DAVF), pseudoaneurysm, true aneurysm, traumatic arteriovenous fistula (AVF), moyamoya disease (MMD), recurrent chronic subdural hematoma (CSDH), migraine and meningioma, can involve the MMA. In these diseases, the lesions occur in either the MMA itself and treatment is necessary, or the MMA is used as the pathway to treat the lesions; therefore, the MMA is very important to the development and treatment of a variety of neurosurgical diseases. However, no systematic review describing the importance of MMA has been published. In this study, we used the PUBMED database to perform a review of the literature on the MMA to increase our understanding of its role in neurosurgery. After performing this review, we found that the MMA was commonly used to access DAVFs and meningiomas. Pseudoaneurysms and true aneurysms in the MMA can be effectively treated via endovascular or surgical removal. In MMD, the MMA plays a very important role in the development of collateral circulation and indirect revascularization. For recurrent CDSHs, after burr hole irrigation and drainage have failed, MMA embolization may be attempted. The MMA can also contribute to the occurrence and treatment of migraines. Because the ophthalmic artery can ectopically originate from the MMA, caution must be taken to avoid causing damage to the MMA during operations.