Anterolaterally Projecting Clinoid Segment Aneurysm Causing Oculomotor Palsy, with an Anatomical Review of the Clinoid Segment of the Internal Carotid Artery.

We describe a rare case of an anterolaterally projecting clinoid segment aneurysm of the internal carotid artery (ICA) causing oculomotor palsy. A 76-year-old woman was referred to our facility because of right oculomotor palsy that had been found just before surgery to remove bilateral cataracts. Neuroimaging revealed that the patient had an aneurysm at the clinoid segment that projected anterolaterally, eroding the anterior clinoid process. The aneurysm was thought to be compressing the oculomotor nerve, which runs at the upper part of the lateral wall of the cavernous sinus, thereby causing oculomotor palsy. Endovascular coiling of the aneurysm was successfully performed, and the oculomotor palsy was alleviated postoperatively. Anatomically, there exists the carotid collar between the arterial wall of the clinoid segment and the anterior clinoid process, containing the clinoid venous plexus in it. Hence, the anterolateral wall of the clinoid segment, although protected by a stiff bony structure, has an anatomical base that allows it to protrude centrifugally. Once protrusion occurs, the bone may be eroded by remodeling caused by the aneurysm's pulsed beating.

[Cervical Myelopathy Caused by Chronic and Intermittent Cord Compression by Tumors upon Neck Rotation:A Case Report].

A 35-year-old man with neurofibromatosis type I presented with right arm weakness and gait disturbance that had developed gradually. MR imaging revealed bilateral intra-and extradural tumors at the C1-2 level. Although the adjacent spinal cord was narrowed, there was no evident contact between the tumors and the spinal cord. Computed tomography myelography revealed that the tumors compressed the cord only during neck rotation. The tumors were resected to make an abundant subdural space around the affected cord. The patient's neurological symptoms improved postoperatively. Because contact between the masses and spinal cord only occurred upon neck rotation, we believe it is important to consider the possibility of intermittent compression, termed dynamic rotational canal stenosis, in patients with masses at the C1-2 level, even when such masses are not seen to be in contact with the cervical cord on routine radiological examination.

Distal superior cerebellar artery aneurysm located at the newly formed anastomotic site with the long circumferential artery of the posterior cerebral artery: A case report.

We describe a case of a distal superior cerebellar artery (SCA) aneurysm that arose from a unique collateral pathway between the SCA and long circumferential artery (LCA) of the posterior cerebral artery (PCA). The patient was a 69-year-old male who was admitted to our facility for an asymptomatic and incidentally identified cerebellar aneurysm. Magnetic resonance imaging showed a saccular aneurysm arising from the right SCA in the quadrigeminal cistern. Digital subtraction angiography revealed an unusually dilated branch from the aneurysmal sac. Furthermore, this branch had retrograde flow from the quadrigeminal segment to the anterior pontomesencephalic segment, was connected to the PCA at the P1 segment, and exited from the P2 segment. We attributed this unusual angioarchitecture to collateral circulation secondary to severe P1 stenosis. Thus, the dilated unusual branch is an LCA of the PCA for supplying the distal PCA with blood flow. As a result, the aneurysm is probably formed at the junction between the SCA and LCA. Endovascular coiling for the aneurysm was successfully performed with preserved collateral system.

Posterior Inferior Cerebellar Artery Originating from the Jugular Branch of the Ascending Pharyngeal Artery.

The variation in which the posterior inferior cerebellar artery arises from the hypoglossal branch of the ascending pharyngeal artery is thought to be related to the remnant of the primitive hypoglossal artery, and is referred to as a primitive hypoglossal artery variant. Cases in which the posterior inferior cerebellar artery arises from the jugular branch of the ascending pharyngeal artery are extremely rare. The authors present a case of a 50-year-old male with vertebral artery dissection who had this extremely rare variation bilaterally. The patient also had several rare variations of the intracranial vessels. This posterior inferior cerebellar artery arising from the jugular branch of the ascending pharyngeal artery may have developed due to the anastomosis between the meningeal and the pial vessels of the posterior fossa. Alternatively, an unknown primitive anastomotic artery may have passed through the jugular foramen. Genetic factors may play an important role in the presence of this anomalous vessel.

Acceleration of blood flow as an indicator of improved hemodynamics after indirect bypass surgery in Moyamoya disease.

OBJECTIVE: The ultrasonography findings in the superficial temporal artery (STA) in Moyamoya disease patients treated with indirect bypass remain unclear. We evaluated the time-related changes in ultrasonography findings of the STA main trunk and branches in patients with Moyamoya disease who underwent encephalo-duro-arterio-synangiosis (EDAS). PATIENTS AND METHODS: Patients (n=21, 30 sides) with Moyamoya disease who underwent EDAS at Fukuoka University Hospital were prospectively registered between 2008 and 2015. EDAS using the frontal and parietal branches of the STA was adopted in an indirect bypass procedure. Mean velocity (MV) and resistance index (RI) were used as ultrasonography markers, and their changes over time in the STA main trunk and branches were assessed. RESULTS: There was a significant increase in MV in both the STA main trunk (p=0.001) and branches (frontal: p=0.005, parietal: p=0.003) at 3 months after EDAS, whereas there was a decrease in RI at 14days after EDAS (main trunk: p <0.001, frontal: p <0.001, parietal: p=0.014). In subgroup analysis of patients divided by EDAS outcome, compared with before EDAS, there were significant differences at 3 months after EDAS in MV (responders: main trunk: p=0.002, frontal: p=0.001, parietal: p=0.001; non-responders: main trunk: p=0.093, frontal: p=0.24, parietal: p=0.96) and RI (responders: main trunk: p<0.001, frontal: p<0.001, parietal: p=0.006; non-responders: main trunk: p=0.17, frontal: p=0.12, parietal: p=0.17). CONCLUSIONS: Measurement of MV may be useful for predicting outcome at 3 months after EDAS.

Early and noninvasive evaluation using superficial temporal artery duplex ultrasonography after indirect bypass for adult ischemic moyamoya disease.

BACKGROUND: The validity of indirect bypass for adult patients with moyamoya disease is still debatable. Some patients are poor responders to indirect bypass, and additive intervention is occasionally required in these cases. Therefore, it is necessary to evaluate the development of collateral circulation as early as possible postoperatively. METHODS: Fifteen adult patients (>17 years old) with moyamoya disease (22 affected sides) who underwent encephalo-duro-arterio-synangiosis (EDAS) at Fukuoka University Hospital from April 2008 to August 2014 were included. All patients had ischemic symptoms of at least one hemisphere. Superficial temporal artery duplex ultrasonography (STDU) was performed before and 3, 6, and 12 months postoperatively. Digital subtraction angiography was performed 1 year after the operation to evaluate the development of collateral circulation. Hemispheres exhibiting collateral formation of more than one-third of the MCA distribution were defined as good responders, and those with less than one-third were defined as poor responders. RESULTS: EDAS induced the formation of well-developed collaterals in 17 of 22 affected sides (77.3%) of adult patients with ischemic moyamoya disease. Regardless of the degree of collateral formation, the ischemic event subsided eventually with time in all patients. In good responders, the pulsatility index obtained by STDU showed a drastic decrease 3 months after the operation, while it did not change significantly in poor responders. Absence of this decrease in the pulsatility index along with no change in the flow velocity reliably indicated poor responders. CONCLUSIONS: Neovascularization after EDAS can be evaluated noninvasively in early phase using STDU.

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.

Extensive Multilocular Spinal Extradural Meningeal Cyst That Developed 16 Years After Traumatic Brachial Plexus Injury: A Case Report.

BACKGROUND: Symptomatic extensive spinal extradural meningeal cyst (SEMC) developing after traumatic brachial plexus injury (TBPI) is rare. We discuss the mechanism of extensive SEMC development, surgical strategies, and preventive measures against SEMC after TBPI. CASE DESCRIPTION: A 58-year-old man with TBPI 16 years previously developed spastic paraparesis of the lower limbs, sensory disturbance below the periumbilical level, and dysfunction of bladder and bowel over 2 years. The patient couldn't walk and was wheelchair bound. Magnetic resonance imaging (MRI) revealed an extensive multilocular extradural cyst posterior to the spinal cord ranging from the C4 to Th6 level, associated with severe spinal cord compression. On constructive interference in steady-state MRI, the cyst was divided, with many septa, and extended to the root sleeves. During the operation, transdural communication sites of cerebrospinal fluid (CSF) into the cyst were revealed at C5/6, C6/7, and C7/Th1 levels around the nerve root sleeves. Treatment involved unroofing of the cyst wall and closure of the transdural CSF communication without cyst removal. Autologous muscle pieces were placed over the defect to close the transdural communication. Two weeks postoperatively, MRI showed decreased cyst size and reduced spinal cord compression, and the patient could walk without support. It was thought that the patient's daily lifting of heavy weights at work and an excessive exercise regimen increased CSF pressure and cyst size after TBPI. CONCLUSION: For patients with TBPI, it is necessary to prevent greater CSF pressure and to perform long-term follow-up MRI after injury.

Successfully Treated Isolated Posterior Spinal Artery Aneurysm Causing Intracranial Subarachnoid Hemorrhage: Case Report.

There are very few published reports of rupture of an isolated posterior spinal artery (PSA) aneurysm, and consequently the optimal therapeutic strategy is debatable. An 84-year-old man presented with sudden onset of restlessness and disorientation. Neuroradiological imaging showed an intracranial subarachnoid hemorrhage (SAH) with no visible intracranial vascular lesion. Spinal magnetic resonance imaging (MRI) detected a localized subarachnoid hematoma at Th10-11. Both contrast-enhanced spinal computed tomography and enhanced MRI and magnetic resonance angiography revealed an area of enhancement within the hematoma. Superselective angiography of the left Th12 intercostal artery demonstrated a faintly enhanced spot in the venous phase. Thirteen days after the onset of symptoms, a small fusiform aneurysm situated on the radiculopial artery was resected. The patient's postoperative course was uneventful and he was eventually discharged in an ambulatory condition. To our knowledge, this 84-year-old man is the oldest reported case of surgical management of a ruptured isolated PSA aneurysm. This case illustrates both the validity and efficacy of this therapeutic approach.

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

OBJECT: The authors experienced an intriguing phenomenon in 2 adult patients with moyamoya disease. Mouth opening caused reversible occlusion of the donor superficial temporal artery (STA), and the patients exhibited transient cerebral ischemic symptoms. The aim of this study was to assess the incidence of such occlusion and the mechanism of this phenomenon. METHODS: Twelve consecutive adult patients with moyamoya disease (15 affected sides) who underwent STA-middle cerebral artery anastomosis were included in this study. Ultrasound examination was performed more than 3 months postoperatively to determine whether mouth opening affected blood flow of the donor STA and led to any ischemic symptoms within 1 minute. Computed tomography angiography was performed during both mouth opening and mouth closing, when blood flow changes of the donor STA were recognized. RESULTS: Under wide mouth opening, steno-occlusion of the donor STA occurred in 5 of 15 sides (33.3%). On 1 side (6.7%), complete occlusion induced ischemic symptoms. Steno-occlusion occurred by at least 2 mechanisms: either the stretched temporalis muscle pushed the donor STA against the edge of the bone window, or the redundant donor STA kinked when the muscle was stretched. CONCLUSIONS: Even with temporary occlusion of the donor STA, ischemic symptoms seem to rarely occur. However, to avoid the "big bite ischemic phenomenon," the authors recommend securing a sufficient distance between the donor STA and the edge of the bone window and avoiding a redundant course of the donor STA within the muscle layer.

Two cases of subfrontal schwannoma, including a rare case located between the endosteal and meningeal layers of the dura.

Subfrontal schwannomas arising from the olfactory groove are rare and their origin remains uncertain because olfactory bulbs do not possess Schwann cells. We present two cases of subfrontal schwannomas treated with surgical resection. In one case, the tumor was located between the endosteal and meningeal layers of the dura mater. This rare case suggests that subfrontal schwannomas may originate from the fila olfactoria.

Deterioration of glaucoma after carotid endarterectomy.

A 64-year-old man with a long history of untreated diabetes mellitus had suffered from visual disturbance in his right eye. Neovascular glaucoma in the right eye and diabetic retinopathy in both eyes were found, and ischemic ocular syndrome was suspected for the right eye. Neuroimaging revealed severe stenosis of the right internal carotid artery. He was first treated for diabetes and glaucoma, and then, after these conditions were stabilized, right carotid endarterectomy (CEA) was carried out. Although the operation was uneventful, he suffered from headache and his right sight was blurred on the day after surgery. Right intraocular pressure was markedly increased, and corneal edema and increased iris neovascularization were also recognized. Intensive ophthalmologic care was carried out, but his right vision worsened and was eventually lost. Ocular ischemia causes not only neovascularization of the iris, which leads to insufficient resorption of the aqueous humor, but also insufficient production of the aqueous humor. After CEA, production of the humor is immediately activated, but the resorption capacity does not change, which results in an extraordinary increase in intraocular pressure. Neurosurgeons should be aware that CEA not only improves or avoids worsening of vision in patients with ischemic oculopathy, but can also rarely cause paradoxical devastating visual deterioration.

[A pregnant case on which EC-IC bypass was successfully performed in the acute phase of brain infarction].

A 30 year-old, 28 weeks-pregnant woman (gravida 2, para 2) suffered from a sudden onset of aphasia when she was having a chat in the upright position. Although the initial symptom soon disappeared, transient attacks of aphasia combined with weakness in the right arm occurred intermittently, particularly when she uprose. MR image disclosed a small acute infarcted focus at the genu of the left internal capsule, while MRA showed an occlusion of the intracranial portion of the left internal carotid artery. She was treated conservatively, but the transient attack continued and her consciousness was slightly lowered. Since repeated examination revealed no recanalization of the occluded artery, treatment was reinforced by using heparin and dopamine on day 1. However, her consciousness was not improved, and dopamine evoked nausea and vomiting. On day 2, superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis was carried out. Soon after surgery, she regained alertness and the transient attack subsided. Examinations could not clarify the course of the occlusion. She was treated with heparin until she delivered a sound baby in the 37th week. Although STA-MCA anastomosis for acute ischemic stroke is still debatable, it may be a good option even for a pregnant woman when suffering from intractable progressing stroke.

A new transvenous approach to the carotid-cavernous sinus via the inferior petrooccipital vein.

OBJECT: The transvenous approach via the inferior petrosal sinus (IPS) is commonly used as the most appropriate for carotid-cavernous fistula (CCF) or cavernous sinus sampling. However, sometimes the IPS is not accessible because of anatomical problems and/or complications, therefore an alternative route is needed. In this paper, the authors present and discuss the utility of a transvenous approach to the cavernous sinus via the inferior petrooccipital vein. METHODS: Four patients, 3 with dural CCFs and the other with Cushing disease, in whom endovascular surgical attempts failed using a conventional venous approach via the IPS, underwent a transvenous approach to the cavernous sinus via the inferior petrooccipital vein (IPOV). One dural CCF case had only cortical venous drainage, the second CCF also mainly drained into the cortical vein with slight inflow into the superior ophthalmic vein and inferior ophthalmic vein, and the third demonstrated drainage into the superior and inferior ophthalmic veins and IPOV. RESULTS: In all cases, the cavernous sinus could be accessed successfully via this route and without complications. CONCLUSIONS: The transvenous approach to the cavernous sinus via the IPOV should be considered as an alternative in cases when use of the IPS is precluded by an anatomical problem and there are no other suitable venous approach routes.

A patient with a dysembryoplastic neuroepithelial tumor who underwent epilepsy surgery after initial seizure.

BACKGROUND: Since dysembryoplastic neuroepithelial tumors (DNTs) are benign tumors that are frequently associated with long-standing medically intractable epilepsy, it is well known that the surgical strategy is resection of the associated epileptogenic zone as well as the tumor. However, the surgical strategy for DNT with a single seizure has not been fully discussed. METHODS: We report an 8-year-old boy with DNT in the nondominant frontal lobe who underwent epilepsy surgery at 3 months after his initial seizure. RESULTS: An intraoperative electrocorticogram revealed frequent paroxysmal cortical activity lateral to the tumor. Since resection of the tumor resulted in persistent paroxysmal activity in this cortex, additional resection was performed. The histological findings in the cortex revealed the presence of cortical dysplasia (CD) (Palmini type IIA). Lesionectomy alone might have left the epileptogenic CD. CONCLUSION: It is thought that epilepsy surgery should be recommended in patients with typical neuroimaging findings of DNT, even if the patients had only one episode of seizure.

[Growing skullbase fracture--a case report with special reference to its pathogenesis].

This report describes a growing skullbase fracture in a six-year-old girl. She had a history of anterior skullbase fracture three years previously and meningitis two years later. She was referred to our hospital because of bacterial meningoencephalitis. Neuroimaging disclosed a bone defect and meningocele at the same site as the previous fracture. Although a growing skull fracture of the anterior cranial base is extremely rare, the reported cases include not only pediatric patients but also adults. Furthermore, posttraumatic pseudo-meningocele or encephalocele can be considered to be part of the same entity as growing skullbase fracture. Therefore, "weakness of surrounding tissue" seems to be another important factor as well as "the expanding force of the growing brain" and "dural tear", which are well-known to be essential in the growth of a fracture. Since a growing fracture at the anterior skullbase is difficult to identify from the outside, it is very important to follow-up changes in the fracture line from the acute stage of injury.

Somatosensory and spinal evoked potentials in patients with upper cervical neurinoma.

Scalp somatosensory evoked potentials (SEPs) and spinal evoked potentials (SpEP) were simultaneously recorded from the exposed surface of the upper cervical cord after median nerve stimulation in five patients undergoing surgery for upper cervical neurinomas. Two of the neurinomas were localized at C1 nerve root, two at C2, and one at C3. All patients showed good postsurgical recovery, suggesting that the tumors had not progressed to the stage where most of the nerve fibers were irreparably damaged. In patients with unaffected superficial and deep skin sensation, both SEP and SpEP were normal. In patients with more advanced tumor, the superficial sensation was abnormal but the deep skin sensation was intact. In these patients, the action potential propagation slowed down but continued partially through the tumor site on the relatively less affected side contralateral to the tumor; however, it stopped at the site of the tumor on the ipsilateral side. It is possible that full functional recovery becomes more difficult during the next stage of tumor development when the propagation of action potentials ceases bilaterally. The intraoperative monitoring of both SEP and SpEP thus appears useful for inferring details of functional integrity and prognosis of the spinal cord near a space-occupying tumor during the critical first two stages of neoplasm in which the spinal function is normal, or a sufficiently large fraction of ascending and descending nerve fibers are functionally suppressed, but are capable of recovery after a surgical intervention.

Ectopic pituitary adenoma in the cavernous sinus causing oculomotor nerve paresis--case report.

A 24-year-old woman presented with a rare adrenocorticotropic hormone (ACTH)-positive pituitary adenoma in the cavernous sinus, manifesting as sudden onset of oculomotor nerve paresis. Neuroimaging revealed a tumor in the cavernous sinus bulging into the subdural space. There was no continuity between the tumor and the pituitary gland in the sella turcica. Gross total removal of the tumor was performed through the orbitozygomatic approach followed by stereotactic radiosurgery. The oculomotor nerve paresis was resolved. Histological examination revealed an adenoma positive for ACTH. Ectopic pituitary adenoma occurs mostly in the sphenoid sinus or the suprasellar region. This extremely rare case of ectopic macroadenoma in the cavernous sinus manifested as oculomotor nerve paresis without signs of Cushing's syndrome.

Distinctions between pituicytoma and ordinary pilocytic astrocytoma. Case report.

The authors present a rare case of pituicytoma. A dynamic magnetic resonance study performed after Gd injection revealed a markedly, homogeneously enhanced, early-phase pituitary lesion in a 32-year-old woman with a 1-year history of amenorrhea. The tumor bled easily during transsphenoidal resection. The lesion consisted of plump spindle cells and lacked Rosenthal fibers and granular bodies, and thus was different from ordinary pilocytic astrocytoma or any other form of this tumor. Although pituicytoma is often confused with pilocytic astrocytoma when it appears in the sellar region, these two kinds of gliomas should be distinguished on the basis of histological differences.