Reversible occlusion of donor vessel caused by mouth opening after superficial temporal artery-middle cerebral artery anastomosis in adult moyamoya patients

A case of temporary occlusion of donor artery after secondary generalized seizure in a patient with superficial temporal artery-middle cerebral artery bypass

Background

To prevent stroke recurrence, a superficial temporal artery-middle cerebral artery (STA-MCA) bypass for atherosclerotic cerebrovascular occlusive disease is performed. Post stroke epilepsy is known as serious sequelae of stroke. Herein, we present a case of a 60-year-old man who underwent STA-MCA bypass for the prevention of stroke recurrence; however, the donor artery was deemed to be temporally occluded secondary to generalized seizure.

Case Description

A 60-year-old man was referred to our hospital with a diagnosis of the left cervical internal carotid artery occlusion presenting with mild aphasia and right hemiparesis. He underwent STA-MCA bypass to prevent the recurrence of stroke 1 month after the onset of symptoms. On postoperative day 7, patency of the donor artery was confirmed on magnetic resonance imaging (MRI), and no complications were noted. However, on postoperative day 14, he presented with a secondary generalized seizure. MRI was immediately performed and the donor artery was not patent with no new lesions. Several hours thereafter, the blood flow of the donor artery was confirmed using pulse Doppler; however, during mouth opening, the flow of the donor artery decreased. Computed tomography-angiography confirmed donor artery patency. An encephalogram was conducted and revealed a focal epilepsy which was compatible with stroke on MRI.

Conclusion

Post stroke epilepsy caused an unintended and forced mouth opening which led to a temporary occlusion of the donor artery after STA-MCA bypass. Thus, this complication should be recognized, and seizures should be prevented through the administration of prophylactic anti-seizure medication based on risk stratification assessment of post stroke epilepsy.

Temporary Steno-occlusive Change in the Donor Artery During Mouth Opening (Big Bite Ischemic Phenomenon) After Superficial Temporal Artery to Middle Cerebral Artery Bypass in Adult Patients with Moyamoya Disease and Atherosclerosis

BACKGROUND

Superficial temporal artery (STA) to middle cerebral artery (MCA) bypass is one of the most common surgical procedures performed for direct extracranial (EC) to intracranial (IC) bypasses. We describe a temporary steno-occlusive change in the STA that was caused by mouth opening after the STA-MCA bypass (so-called big bite ischemic phenomenon) in an adult patient with moyamoya disease. The aim of this study was to assess the incidence of this phenomenon in patients with atherosclerosis.

METHODS

Adult patients with ischemic cerebrovascular disease who underwent STA-MCA anastomosis were included in this study. Ultrasound examinations were postoperatively performed on 62 sides to determine whether mouth opening affected the blood flow of the donor STA and resulted in any ischemic symptoms within 1 min. Computed tomography angiography was performed during both mouth opening and closing when blood flow changes were recognized in the donor STA.

RESULTS

During wide mouth opening, steno-occlusion of the donor STA occurred in 8 of the 62 affected sides (12.9 %), which included 3 of the 47 sides (6.4 %) in patients with atherosclerosis and 5 of the 15 sides (33.3 %) in patients with moyamoya disease.

CONCLUSION

Steno-occlusion of the donor STA occurred during wide mouth opening in 12.9 % of the sides of adult patients who had undergone STA-MCA anastomosis. This phenomenon was more common in patients with moyamoya disease than in patients with atherosclerosis.

Effect of Adventitial Dissection of Superficial Temporal Artery on the Outcome of Superficial Temporal Artery-Middle Cerebral Artery Bypass in Moyamoya Disease

Superficial temporal artery-middle cerebral artery (STA-MCA) has been used for the treatment of occlusive cerebrovascular disease including moyamoya disease. The effect of STA-MCA bypass depends not only on the patency of anastomosis, but also on integrity and functional capacity of the donor artery. In the present prospective study, we investigated the effect of extensive stripping STA adventitia and fasciae on hemodynamic function in STA-MCA bypass of moyamoya disease patients. Twenty patients (n=8 in control group, n=12 in stripping group) of moyamoya disease were subjected to STA-MCA end-to-side direct anastomosis. Perfusion unit (PU) values of the cortex were measured and recorded using a Laser Doppler flowmetry (LDF) for 5 days. Computed tomography perfusion was performed to determine blood flow before and after bypass. No patient experienced significant neurologic deficits associated with neurosurgical complications. LDF demonstrated that adventitial stripping group had higher cerebral blood flow increase than control group. The adventitia stripping group tends to have higher rate of increased cerebral perfusion after bypass than non-stripping group. Furthermore, the ultrasound examination at 3 days after bypass demonstrated that the adventitial stripping group has a tendency of bigger STA and higher peak systolic velocity than control group. Our result suggests that stripping adventitia of STA improves hemodynamics of STA-MCA bypass in moyamoya disease.

Histopathological features of middle cerebral artery and superficial temporal artery from patients with moyamoya disease and enlightenments on clinical treatment

The histopathological features of the middle cerebral artery (MCA) and superficial temporal artery (STA) from moyamoya disease (MMD) and their relationships with gender, age, angiography stage were explored. The causes and the clinical significance of vasculopathy of STA were also discussed. The clinical data and specimens of MCA and STA from 30 MMD patients were collected. Twelve samples of MCA and STA from non-MMD patients served as control group. Histopathological examination was then performed by measuring the thickness of intima and media, and statistical analysis was conducted. The MCA and STA specimens from MMD group had apparently thicker intima and thinner media than those from the control group. There was no significant pathological difference between the hemorrhage group and non-hemorrhage group, and between the males and females in MMD patients. Neither the age nor the digital subtraction angiography (DSA) stage was correlated with the thickness of intima in MCA and STA. MMD is a systemic vascular disease involving both intracranial and extracranial vessels. Preoperative external carotid arteriography, especially super-selective arteriography of the STA, benefits the selection of donor vessel.

Progress on Complications of Direct Bypass for Moyamoya Disease

Moyamoya disease (MMD) involves progressive occlusion of the intracranial internal carotid artery resulting in formation of moyamoya-like vessels at the base of the brain. It can be characterized by hemorrhage or ischemia. Direct vascular bypass is the main and most effective treatment of MMD. However, patients with MMD differ from those with normal cerebral vessels. MMD patients have unstable intracranial artery hemodynamics and a poor blood flow reserve; therefore, during the direct bypass of superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis, perioperative risk factors and anesthesia can affect the hemodynamics of these patients. When brain tissue cannot tolerate a high blood flow rate, it becomes prone to hyperperfusion syndrome, which leads to neurological function defects and can even cause intracranial hemorrhage in severe cases. The brain tissue is prone to infarction when hemodynamic equilibrium is affected. In addition, bypass vessels become susceptible to occlusion or atrophy when blood resistance increases. Even compression of the temporalis affects bypass vessels. Because the STA is used in MMD surgery, the scalp becomes ischemic and is likely to develop necrosis and infection. These complications of MMD surgery are difficult to manage and are not well understood. To date, no systematic studies of the complications that occur after direct bypass in MMD have been performed, and reported complications are hidden among various case studies; therefore, this paper presents a review and summary of the literature in PubMed on the complications of direct bypass in MMD.