BACKGROUND: Selecting therapeutic options for moyamoya disease (MMD)-associated anterior communicating artery (ACoA) aneurysm, a rare pathology in children, is challenging because its natural course remains unclear.
METHODS: A 4-year-old boy exhibiting transient ischemic attacks was diagnosed with unilateral MMD accompanied by an unruptured ACoA aneurysm. Although superficial temporal artery to middle cerebral artery anastomosis eliminated his symptoms, the aneurysm continued to grow after surgery. Since a previous craniotomy and narrow endovascular access at the ACoA precluded both aneurysmal clipping and coil embolization, the patient underwent a surgical anastomosis incorporating an occipital artery graft between the bilateral cortical anterior cerebral arteries (ACAs). This was intended to augment blood flow in the ipsilateral ACA territory and to reduce the hemodynamic burden on the ACoA complex. The postoperative course was uneventful, and radiological images obtained 12 months after surgery revealed good patency of the bypass and marked shrinkage of the aneurysm in spite of the intact contralateral internal carotid artery.
CONCLUSIONS: Various clinical scenarios should be assessed carefully with regard to this pathology. Bypass surgery aimed at reducing flow to the aneurysm might be an alternative therapeutic option when neither coiling nor clipping is feasible.

BACKGROUND: Giant pituitary macroadenomas with a diameter >4 cm are rare tumors, accounting for only about 5% of pituitary adenomas. They are more difficult to maximally resect safely owing to limited access as well as encasement of adjacent structures. Acidophil stem cell adenomas are rare immature neoplasms proposed to derive from common progenitor cells of somatotroph and lactotroph cells. These adenomas comprise about 4.3% of surgically removed pituitary adenomas. No previous reports have described acidophil stem cell adenomas that grow to the size of giant macroadenomas. This rare entity poses special challenges given the need for maximal safe resection in an immature neoplasm.
METHODS: The authors report a 21-year-old female who presented with 3 years of progressive visual decline and a giant macroadenoma. She underwent endoscopic transsphenoidal surgery for decompression. Given the tumor size and involvement of adjacent critical structures, gross-total resection was not achieved. The authors review the literature on giant pituitary adenomas and provide a discussion on clinical management for this rare entity.
CONCLUSIONS: The authors present a very rare case of a giant pituitary adenoma of acidophil stem cell origin and discuss the technical and management challenges in this rare entity.

BACKGROUND: Limb-shaking transient ischemic attacks (LS-TIAs) are a rare form of TIAs that present as involuntary movements of the limbs and indicate severe cerebral hypoperfusion. LS-TIAs are often reported in patients with carotid artery stenosis but can also affect patients with intracranial artery stenosis and moyamoya disease (MMD).
METHODS: A 72-year-old woman presented with repeated episodes of involuntary shaking movements of the right upper limb. Cerebral angiography revealed complete occlusion of the M1 segment of the left middle cerebral artery (MCA), and the left hemisphere was supplied by moyamoya vessels. She was treated with left direct revascularization without complications, and her involuntary movements subsided. However, she demonstrated involuntary shaking movements of the right lower limb 2 months postoperatively. Cerebral angiography revealed complete occlusion of the A1 segment of the left anterior cerebral artery (ACA). The multiple burr hole opening (MBHO) procedure was performed to improve perfusion in the left ACA territory and after 3 months, the patient\'s symptoms resolved.
CONCLUSIONS: This case demonstrated that LS-TIAs can also develop as ischemic symptoms due to MMD. Moreover, instances of LS-TIA of the upper and lower limbs developed separately in the same patient. The patient\'s symptoms improved with direct revascularization and MBHO.

BACKGROUND: Large pituitary adenomas can rarely cause compression of the cavernous internal carotid artery (ICA) due to chronic tumor compression or invasion. Here, the authors present a case of pituitary apoplexy causing acute bilateral ICA occlusion with resultant stroke. Our middle-aged patient presented with sudden vision loss and experienced rapid deterioration requiring intubation. Computed tomography (CT) angiography revealed a large pituitary mass causing severe stenosis of the bilateral ICAs. CT perfusion revealed a significant perfusion delay in the anterior circulation. The patient was taken for cerebral angiography, and balloon angioplasty was attempted with no improvement in arterial flow. Resection of the tumor was then performed, with successful restoration of blood flow. Despite restoration of luminal patency, the patient experienced bilateral ICA infarcts.
METHODS: Pituitary apoplexy can present as an acute stroke due to flow-limiting carotid compression. Balloon angioplasty is ineffective for the treatment of this type of compression. Surgical removal of the tumor restores the flow and luminal caliber of the ICA.
CONCLUSIONS: Pituitary apoplexy can be a rare presentation of acute stroke and should be managed with immediate surgical decompression rather than attempted angioplasty in order to restore blood flow and prevent the development of cerebral ischemia.

BACKGROUND: The authors report on four clinical cases with intraarterial verapamil administration to resolve vasospasm in patients who underwent surgery for intracranial tumors. Iatrogenic subarachnoid hemorrhage after tumor resection and subsequent vasospasm (an increase in the systolic linear velocity of blood flow through the M1 segment of the middle cerebral artery of more than 250 cm/sec; Lindegaard index: 4.1) were observed in four patients during the early postoperative period after the removal of intracerebral tumors. Each vasospasm case was confirmed by angiography data, was clinically significant, and manifested as the development of a neurological deficit.
METHODS: Resolution of vasospasm with the intraarterial administration of verapamil was achieved in all four cases as confirmed by angiographic data in all four cases and complete regression of neurological symptoms in two cases. In all four presented cases, vasospasm was resolved; unfortunately, the resolution did not always lead to significant clinical improvement. However, lethal outcomes were avoided in two cases, and almost full recoveries were achieved in the other two.
CONCLUSIONS: The authors believe that the removal of intracranial tumors can cause expected and potential complications, such as cerebral vasospasm, which must be diagnosed and treated in a timely manner.

BACKGROUND: Idiopathic dissecting cerebral aneurysms (IDCAs) are male dominant but are extremely rare in children. Many IDCAs in children are located in the posterior cerebral artery and the supraclinoid internal cervical artery. No cases of IDCA of the distal anterior cerebral artery (ACA) have been reported.
METHODS: A previously healthy 7-month-old boy experienced afebrile seizures and presented at the authors\' hospital 1 week after the first seizure. He was not feeling well but had no neurological deficits. The authors diagnosed a ruptured aneurysm of the right distal ACA based on imaging results. He underwent emergency craniotomy to prevent re-rupture of the aneurysm. Using intraoperative indocyanine green videoangiography, the authors confirmed peripheral blood flow and then performed aneurysmectomy. Pathological examination of the aneurysm revealed a thickened intima, fragmentation of the internal elastic lamina, and a hematoma in the aneurysmal wall. The authors ultimately diagnosed IDCA because no cause was indicated, including a history of trauma. The boy recovered after surgery and was subsequently discharged with no complications.
CONCLUSIONS: The authors reported, for the first time, IDCA of the distal ACA in an infant. The trapping technique is often used for giant fusiform aneurysms in infants. Indocyanine green videoangiography is useful for evaluating peripheral blood flow during trapping in this case.

Functional hemispherectomy/hemispherotomy is a disconnection procedure for severe medically refractory epilepsy where the seizure foci diffusely localize to one hemisphere. It is an improvement on anatomical hemispherectomy and was first performed by Rasmussen in 1974. Less invasive surgical approaches and refinements have been made to improve seizure freedom and minimize surgical morbidity and complications. Key anatomical structures that are disconnected include the 1) internal capsule and corona radiata, 2) mesial temporal structures, 3) insula, 4) corpus callosum, 5) parietooccipital connection, and 6) frontobasal connection. A stepwise approach is indicated to ensure adequate disconnection and prevent seizure persistence or recurrence. In young pediatric patients, careful patient selection and modern surgical techniques have resulted in > 80% seizure freedom and very good functional outcome. In this report, the authors summarize the history of hemispherectomy and its development and present a graphical guide for this anatomically challenging procedure. The use of the osteoplastic flap to improve outcome and the management of hydrocephalus are discussed.

Transcranial Doppler (TCD) ultrasonography is an inexpensive, noninvasive means of measuring blood flow within the arteries of the brain. In this review, the authors outline the technology underlying TCD ultrasonography and describe its uses in patients with neurosurgical diseases. One of the most common uses of TCD ultrasonography is monitoring for vasospasm following subarachnoid hemorrhage. In this setting, elevated blood flow velocities serve as a proxy for vasospasm and can herald the onset of ischemia. TCD ultrasonography is also useful in the evaluation and management of occlusive cerebrovascular disease. Monitoring for microembolic signals enables stratification of stroke risk due to carotid stenosis and can also be used to clarify stroke etiology. TCD ultrasonography can identify patients with exhausted cerebrovascular reserve, and after extracranial-intracranial bypass procedures it can be used to assess adequacy of flow through the graft. Finally, assessment of cerebral autoregulation can be performed using TCD ultrasonography, providing data important to the management of patients with severe traumatic brain injury. As the clinical applications of TCD ultrasonography have expanded over time, so has their importance in the management of neurosurgical patients. Familiarity with this diagnostic tool is crucial for the modern neurological surgeon.

Moyamoya syndrome predisposes patients to ischemic or hemorrhagic stroke due to progressive narrowing of intracranial vessels with subsequent small-vessel collateralization. Dural arteriovenous fistulae (DAVFs) are most commonly noted after venous sinus or cortical vein thrombosis and are believed to be primarily due to venous hypertension and elevated sinus pressures, although there is no known association with moyamoya syndrome, or with surgical treatment for moyamoya disease (MMD). The authors present the case of a 14-year-old girl with Down syndrome treated using pial synangiosis for MMD who subsequently was noted to have bilateral DAVFs. This case provides a new perspective on the origins and underlying pathophysiology of both moyamoya syndrome and DAVFs, and also serves to highlight the importance of monitoring the moyamoya population closely for de novo cerebrovascular changes after revascularization procedures.

During the microsurgical clipping of known aneurysms, angiographically occult (AO) aneurysms are sometimes found and treated simultaneously to prevent their growth and protect the patient from future rupture or reoperation. The authors analyzed the incidence, treatment, and outcomes associated with AO aneurysms to determine whether limited surgical exploration around the known aneurysm was safe and justified given the known limitations of diagnostic angiography.
An AO aneurysm was defined as a saccular aneurysm detected using the operative microscope during dissection of a known aneurysm, and not detected on preoperative catheter angiography. A prospective database was retrospectively reviewed to identify patients with AO aneurysms treated microsurgically over a 20-year period.
One hundred fifteen AO aneurysms (4.0%) were identified during 2867 distinct craniotomies for aneurysm clipping. The most common locations for AO aneurysms were the middle cerebral artery (60 aneurysms, 54.1%) and the anterior cerebral artery (20 aneurysms, 18.0%). Fifty-six AO aneurysms (50.5%) were located on the same artery as the known saccular aneurysm. Most AO aneurysms (95.5%) were clipped and there was no attributed morbidity. The most common causes of failed angiographic detection were superimposition of a large aneurysm (type 1, 30.6%), a small aneurysm (type 2, 18.9%), or an adjacent normal artery (type 3, 36.9%). Multivariate analysis identified multiple known aneurysms (odds ratio [OR] 3.45, 95% confidence interval [CI] 2.16-5.49, p < 0.0001) and young age (OR 0.981, 95% CI 0.965-0.997, p = 0.0226) as independent predictors of AO aneurysms.
Meticulous inspection of common aneurysm sites within the surgical field will identify AO aneurysms during microsurgical dissection of another known aneurysm. Simultaneous identification and treatment of these additional undiagnosed aneurysms can spare patients later rupture or reoperation, particularly in those with multiple known aneurysms and a history of subarachnoid hemorrhage. Limited microsurgical exploration around a known aneurysm can be performed safely without additional morbidity.